WorldWideScience

Sample records for hippocampus abdominalis choosy

  1. Anti-fatigue activity of a mixture of seahorse (Hippocampus abdominalis hydrolysate and red ginseng

    Directory of Open Access Journals (Sweden)

    Nalae Kang

    2017-03-01

    Full Text Available Abstract Seahorse, a syngnathidae fish, is one of the important organisms used in Chinese traditional medicine. Hippocampus abdominalis, a seahorse species successfully cultured in Korea, was validated for use in food by the Ministry of Food and Drug Safety in February 2016; however. the validation was restricted to 50% of the entire composition. Therefore, to use H. abdominalis as a food ingredient, H. abdominalis has to be prepared as a mixture by adding other materials. In this study, the effect of H. abdominalis on muscles was investigated to scientifically verify its potential bioactivity. In addition, the anti-fatigue activity of a mixture comprising H. abdominalis and red ginseng (RG was evaluated to commercially utilize H. abdominalis in food industry. H. abdominalis was hydrolyzed using Alcalase, a protease, and the effect of H. abdominalis hydrolysate (HH on the muscles was assessed in C2C12 myoblasts by measuring cell proliferation and glycogen content. In addition, the mixtures comprising HH and RG were prepared at different percentages of RG to HH (20, 30, 40, 50, 60, 70, and 80% RG, and the anti-fatigue activity of these mixtures against oxidative stress was assessed in C2C12 myoblasts. In C2C12 myoblasts, H2O2-induced oxidative stress caused a decrease in viability and physical fatigue-related biomarkers such as glycogen and ATP contents. However, treatment with RG and HH mixtures increased cell viability and the content of fatigue-related biomarkers. In particular, the 80% RG mixture showed an optimum effect on cell viability and ATP synthesis activity. In this study, all results indicated that HH had anti-fatigue activity at concentrations approved for use in food by the law in Korea. Especially, an 80% RG to HH mixture can be used in food for ameliorating fatigue.

  2. Genetic monogamy despite social promiscuity in the pot-bellied seahorse (Hippocampus abdominalis).

    Science.gov (United States)

    Wilson, A B; Martin-Smith, K M

    2007-06-01

    Sexual selection theory predicts a positive correlation between relative parental investment and mate choice. In syngnathid fishes (seahorses and pipefish), males brood offspring in specialized brooding structures. While female-female mating competition has been demonstrated in some pipefishes, all seahorses (genus Hippocampus) studied to date have been found to have conventional sex roles with greater male-male competition for access to mates despite possessing the most complex brood structures in the family. Although multiple mating is common in pipefish, seahorses are again exceptional, exhibiting strict genetic monogamy. Both demographic and behavioural explanations have been offered to explain the lack of multiple mating in seahorse species, but these hypotheses have not yet been explicitly addressed. We investigated mating systems and brood parentage of the pot-bellied seahorse, Hippocampus abdominalis, a temperate-water species that is socially promiscuous with conventional sex roles in laboratory populations. We observed promiscuous courtship behaviour and sex-role reversal in high density, female-biased field populations of H. abdominalis. We hypothesize that sex roles are plastic in H. abdominalis, depending on local population density and sex ratio. Despite promiscuous courtship behaviour, all assayed male seahorses were genetically monogamous in both laboratory and wild populations. Physiological limitations associated with embryo incubation may explain the absence of multiple mating in seahorses and may have played an important role in the development of the unique reproductive behaviour typical in these species.

  3. The complete mitochondrial genome of the big-belly seahorse, Hippocampus abdominalis (Lesson 1827).

    Science.gov (United States)

    Wang, Lei; Chen, Zaizhong; Leng, Xiangjun; Gao, Jianzhong; Chen, Xiaowu; Li, Zhongpu; Sun, Peiying; Zhao, Yuming

    2016-11-01

    In this study, the complete mitogenome sequence of the big-belly seahorse, Hippocampus abdominalis (Lesson, 1827) (Syngnathiformes: Syngnathidae), has been sequenced by the next-generation sequencing method. The assembled mitogenome is 16 521 bp in length which includes 13 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs genes. The overall base composition of the seahorse is 31.1% for A, 23.6% for C, 16.0% for G, 29.3% for T and shows 87% identities similar to tiger tail seahorse, Hippocampus comes. The complete mitogenome of the big-belly seahorse provides essential and important DNA molecular data for further phylogeography and evolutionary analysis for seahorse family.

  4. Molecular characterization, transcriptional profiling, and antibacterial potential of G-type lysozyme from seahorse (Hippocampus abdominalis).

    Science.gov (United States)

    Ko, Jiyeon; Wan, Qiang; Bathige, S D N K; Lee, Jehee

    2016-11-01

    Lysozymes are a family of enzymes that catalyze the hydrolysis of bacterial cell wall, acting as antimicrobial effectors of the innate immune system. In the present study, an ortholog of goose-type lysozyme (ShLysG) from the big-belly seahorse (Hippocampus abdominalis) was identified and characterized structurally and functionally. The full-length cDNA sequence (1213 bp) of ShLysG is comprised of an open reading frame made up of 552 bp, encoding a polypeptide of 184 amino acid (aa) with a predicted molecular mass of 20 kDa. In silico analysis of ShLysG revealed the absence of signal peptide and the presence of a characteristic bacterial soluble lytic transglycosylase (SLT) domain bearing three catalytic residues (Glu 71 , Asp 84 , and Asp 95 ) and seven N-acetyl-d-glucosamine binding sites (Glu 71 , Asp 95 , Tyr 98 , His 99 , Ile 117 , Tyr 145 , and Asn 146 ). Homology analysis demonstrated that the aa sequence of ShLysG shared 60.7-67.4% identity and 72.6-79.3% similarity with the orthologs of other teleosts. Phylogenetic analysis of ShLysG indicated a closest relationship with the ortholog from Gadus morhua. In healthy seahorse, ShLysG mRNA showed a constitutive expression in all the tissues examined, with the highest expression in kidney and the least expression in liver. The ShLysG mRNA levels were also shown significant elevation upon the bacterial and pathogen-associated molecular pattern (PAMPs) challenges. Furthermore, lytic activities of ShLysG recombinant protein were detected against several Gram-negative and Gram-positive bacterial species. Taken together, these results suggest that ShLysG might possess a potential immune defensive role against invading microbial pathogens in seahorse. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Molecular and functional characterization of caspase-8 from the big-belly seahorse (Hippocampus abdominalis).

    Science.gov (United States)

    Oh, Minyoung; Elvitigala, Don Anushka Sandaruwan; Bathige, S D N K; Lee, Seongdo; Kim, Myoung-Jin; Lee, Jehee

    2016-11-01

    Apoptosis is a physiological process that can also participate in host immune defense mechanisms, including tumor growth suppression along with homeostasis and maturation of immune cells. Caspases are known to be involved in cellular apoptotic signaling; among them, caspase-8 plays an important role in the initiation phase of the apoptotic death cascade. In the current study, we molecularly characterized a caspase-8 homolog (designated as HaCasp-8) from Hippocampus abdominalis. The HaCasp-8 gene harbors a 1476 bp open reading frame (ORF) that codes for a protein of 492 amino acids (aa) with a predicted molecular mass of 55 kDa. HaCasp-8 houses the typical domain architecture of known initiator caspases, including the death effector domain and the carboxyl-terminal catalytic domain. As expected, phylogenetic analysis reflected a closer evolutionary relationship of HaCasp-8 with its teleostean similitudes. The results of our qPCR assays confirmed the ubiquitous expression of HaCasp-8 in physiologically important tissues examined, with pronounced expression levels in ovary tissues, followed by blood cells. HaCasp-8 expression at the mRNA level was found to be significantly modulated by lipopolysaccharide, polyinosinic:polycytidylic acid, Streptococcus iniae, and Edwardsiella tarda injection. Overexpression of HaCasp-8 could trigger a significant level of cell death in HEK293T cells, suggesting its putative role in cell death. Taken together, our findings suggest that HaCasp-8 is an important component in the caspase cascade, and its expression can be significantly modulated under pathogen stress conditions in the big-belly seahorse. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Morphology of brood pouch formation in the pot-bellied seahorse Hippocampus abdominalis.

    Science.gov (United States)

    Kawaguchi, Mari; Okubo, Ryohei; Harada, Akari; Miyasaka, Kazuki; Takada, Kensuke; Hiroi, Junya; Yasumasu, Shigeki

    2017-01-01

    The reproductive strategies of vertebrates are diverse. Seahorses (Pisces: Syngnathidae) possess the unique characteristic of male pregnancy; i.e., males, not females, incubate embryos in a specialized structure called a 'brood pouch'. The brood pouch is formed along the ventral midline of the tail. The lumen of the brood pouch is surrounded by loose connective tissue, called pseudoplacenta, and dermis. We visualized and evaluated the morphology of brood pouch formation in Hippocampus abdominalis to gain generalizable insights into this process in seahorses. First, we employed several staining methods to characterize the pseudoplacenta and dermis of the brood pouch of mature male seahorses. The pseudoplacenta is composed mainly of reticular fibers, while the dermis is composed mainly of collagenous fibers. Further observations showed that pouch formation is initiated by linear projections of epithelia on both ventrolateral sides of the body. These projections elongated toward the ventral midline, eventually fused together, and then formed a baggy structure composed of a single dermis layer with neither smooth muscle nor pseudoplacenta. Finally, the pseudoplacenta was formed, together with two layers of dermis and smooth muscle. Thus, a fully developed brood pouch was established. The morphology of the luminal epithelium also changed during pouch formation. We analyzed the localization of C-type lectins as markers; haCTL II was localized in both the outer and luminal epithelia of the brood pouch throughout development in the male seahorse, whereas haCTL IV, which was not detected in the early stage of seahorse development, became localized only in the luminal epithelium as development proceeded. We categorized the processes of brood pouch formation during male seahorse development into three stages: (1) the early stage, characterized by formation of a baggy structure from the primordium; (2) the middle stage, characterized by the differentiation and establishment of

  7. Diseases of captive yellow seahorse Hippocampus kuda Bleeker, pot-bellied seahorse Hippocampus abdominalis Lesson and weedy seadragon Phyllopteryx taeniolatus (Lacépède).

    Science.gov (United States)

    LePage, V; Young, J; Dutton, C J; Crawshaw, G; Paré, J A; Kummrow, M; McLelland, D J; Huber, P; Young, K; Russell, S; Al-Hussinee, L; Lumsden, J S

    2015-05-01

    Seahorses, pipefish and seadragons are fish of the Family Syngnathidae. From 1998 to 2010, 172 syngnathid cases from the Toronto Zoo were submitted for post-mortem diagnostics and retrospectively examined. Among the submitted species were yellow seahorses Hippocampus kuda Bleeker (n=133), pot-bellied seahorses Hippocampus abdominalis Lesson (n=35) and weedy seadragons Phyllopteryx taeniolatus (Lacépède; n=4). The three most common causes of morbidity and mortality in this population were bacterial dermatitis, bilaterally symmetrical myopathy and mycobacteriosis, accounting for 24%, 17% and 15% of cases, respectively. Inflammatory processes were the most common diagnoses, present in 117 cases. Seven neoplasms were diagnosed, environmental aetiologies were identified in 46 cases, and two congenital defects were identified. © 2014 John Wiley & Sons Ltd.

  8. Identification and molecular profiling of DC-SIGN-like from big belly seahorse (Hippocampus abdominalis) inferring its potential relevancy in host immunity.

    Science.gov (United States)

    Jo, Eunyoung; Elvitigala, Don Anushka Sandaruwan; Wan, Qiang; Oh, Minyoung; Oh, Chulhong; Lee, Jehee

    2017-12-01

    Dendritic-cell-specific ICAM-3-grabbing non-integrin (DC-SIGN) is a C-type lectin that functions as a pattern recognition receptor by recognizing pathogen-associated molecular patterns (PAMPs). It is also involved in various events of the dendritic cell (DC) life cycle, such as DC migration, antigen capture and presentation, and T cell priming. In this study, a DC-SIGN-like gene from the big belly seahorse Hippocampus abdominalis (designated as ShDCS-like) was identified and molecularly characterized. The putative, complete ORF was found to be 1368 bp in length, encoding a protein of 462 amino acids with a molecular mass of 52.6 kDa and a theoretical isoelectric point of 8.26. The deduced amino acid sequence contains a single carbohydrate recognition domain (CRD), in which six conserved cysteine residues and two Ca 2+ -binding site motifs (QPN, WND) were identified. Based on pairwise sequence analysis, ShDCS-like exhibits the highest amino acid identity (94.6%) and similarity (97.4%) with DC-SIGN-like counterpart from tiger tail seahorse Hippocampus comes. Quantitative real-time PCR revealed that ShDCS-like mRNA is transcribed universally in all tissues examined, but with abundance in kidney and gill tissues. The basal mRNA expression of ShDCS-like was modulated in blood cell, kidney, gill and liver tissues in response to the stimulation of healthy fish with lipopolysaccharides (LPS), Edwardsiella tarda, or Streptococcus iniae. Moreover, recombinant ShDCS-like-CRD domain exhibited detectable agglutination activity against different bacteria. Collectively, these results suggest that ShDCS-like may potentially involve in immune function in big belly seahorses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Characterization of a 1-cysteine peroxiredoxin from big-belly seahorse (Hippocampus abdominalis); insights into host antioxidant defense, molecular profiling and its expressional response to septic conditions.

    Science.gov (United States)

    Godahewa, G I; Perera, N C N; Elvitigala, Don Anushka Sandaruwan; Jayasooriya, R G P T; Kim, Gi-Young; Lee, Jehee

    2016-10-01

    1-cysteine peroxiredoxin (Prx6) is an antioxidant enzyme that protects cells by detoxifying multiple peroxide species. This study aimed to describe molecular features, functional assessments and potential immune responses of Prx6 identified from the big-belly seahorse, Hippocampus abdominalis (HaPrx6). The complete ORF (666 bp) of HaPrx6 encodes a polypeptide (24 kDa) of 222 amino acids, and harbors a prominent peroxiredoxin super-family domain, a peroxidatic catalytic center, and a peroxidatic cysteine. The deduced amino acid sequence of HaPrx6 shares a relatively high amino acid sequence similarity and close evolutionary relationship with Oplegnathus fasciatus Prx6. The purified recombinant HaPrx6 protein (rHaPrx6) was shown to protect plasmid DNA in the Metal Catalyzed Oxidation (MCO) assay and, together with 1,4-Dithiothreitol (DTT), protected human leukemia THP-1 cells from extracellular H2O2-mediated cell death. In addition, quantitative real-time PCR revealed that HaPrx6 mRNA was constitutively expressed in 14 different tissues, with the highest expression observed in liver tissue. Inductive transcriptional responses were observed in liver and kidney tissues of fish after treating them with bacterial stimuli, including LPS, Edwardsiella tarda, and Streptococcus iniae. These results suggest that HaPrx6 may play an important role in the immune response of the big-belly seahorse against microbial infection. Collectively, these findings provide structural and functional insights into HaPrx6. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Molecular cloning, biochemical characterization, and expression analysis of two glutathione S-transferase paralogs from the big-belly seahorse (Hippocampus abdominalis).

    Science.gov (United States)

    Tharuka, M D Neranjan; Bathige, S D N K; Lee, Jehee

    2017-12-01

    Glutathione S-transferases (GSTs, EC 2.5.1.18) are important Phase II detoxifying enzymes that catalyze hydrophobic, electrophilic xenobiotic substance with the conjugation of reduced glutathione (GSH). In this study, GSTμ and GSTρ paralogs of GST in the big belly seahorse (Hippocampus abdominalis; HaGSTρ, HaGSTμ) were biochemically, molecularly, functionally characterized to determine their detoxification range and protective capacities upon different pathogenic stresses. HaGSTρ and HaGSTμ are composed of coding sequences of 681bp and 654bp, which encode proteins 225 and 217 amino acids, with predicted molecular masses of 26.06kDa and 25.74kDa respectively. Sequence analysis revealed that both HaGSTs comprise the characteristic GSH-binding site in the thioredoxin-like N-terminal domain and substrate binding site in the C-terminal domain. The recombinant HaGSTρ and HaGSTμ proteins catalyzed the model GST substrate 1-chloro-2, 4-dinitrobenzene (CDNB). Enzyme kinetic analysis revealed different K m and V max values for each rHaGST, suggesting that they have different conjugation rates. The optimum conditions (pH, temperature) and inhibitory assays of each protein demonstrated different optimal ranges. However, HaGSTμ was highly expressed in the ovary and gill, whereas HaGSTρ was highly expressed in the gill and pouch. mRNA expression of HaGSTρ and HaGSTμ was significantly elevated upon lipopolysaccharide, Poly (I:C), and Edwardsiella tarda challenges in liver and in blood cells as well as with Streptococcus iniae challenge in blood cells. From these collective experimental results, we propose that HaGSTρ and HaGSTμ are effective in detoxifying xenobiotic toxic agents, and importantly, their mRNA expression could be stimulated by immunological stress signals in the aquatic environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Manganese-superoxide dismutase (MnSOD), a role player in seahorse (Hippocampus abdominalis) antioxidant defense system and adaptive immune system.

    Science.gov (United States)

    Perera, N C N; Godahewa, G I; Lee, Seongdo; Kim, Myoung-Jin; Hwang, Jee Youn; Kwon, Mun Gyeong; Hwang, Seong Don; Lee, Jehee

    2017-09-01

    Manganese superoxide dismutase (MnSOD) is a metaloenzyme that catalyzes dismutation of the hazardous superoxide radicals into less hazardous H 2 O 2 and H 2 O. Here, we identified a homolog of MnSOD from big belly seahorse (Hippocampus abdominalis; HaMnSOD) and characterized its structural and functional features. HaMnSOD transcript possessed an open reading frame (ORF) of 672 bp which codes for a peptide of 223 amino acids. Pairwise alignment showed that HaMnSOD shared highest identity with rock bream MnSOD. Results of the phylogenetic analysis of HaMnSOD revealed a close proximity with rock bream MnSOD which was consistent with the result of homology alignment. The intense expression of HaMnSOD was observed in the ovary, followed by the heart and the brain. Further, immune related responses of HaMnSOD towards pathogenic stimulation were observed through bacterial and viral challenges. Highest HaMnSOD expression in response to stimulants Edwardsiella tarda, Streptococcus iniae, lipopolysaccharide (LPS), and polyinosinic-polycytidylic acid (Poly I:C) was observed in the late stage in the blood tissue. Xanthine/xanthine oxidase assay (XOD assay) indicated the ROS-scavenging ability of purified recombinant HaMnSOD (rHaMnSOD). The optimum conditions for the SOD activity of rHaMnSOD were pH 9 and the 25 °C. Collectively, the results obtained through the expressional analysis profiles and the functional assays provide insights into potential immune related and antioxidant roles of HaMnSOD in the big belly seahorse. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. The impact of sex-role reversal on the diversity of the major histocompatibility complex: insights from the seahorse (Hippocampus abdominalis).

    Science.gov (United States)

    Bahr, Angela; Wilson, Anthony B

    2011-05-10

    Both natural and sexual selection are thought to influence genetic diversity, but the study of the relative importance of these two factors on ecologically-relevant traits has traditionally focused on species with conventional sex-roles, with male-male competition and female-based mate choice. With its high variability and significance in both immune function and olfactory-mediated mate choice, the major histocompatibility complex (MHC/MH) is an ideal system in which to evaluate the relative contributions of these two selective forces to genetic diversity. Intrasexual competition and mate choice are both reversed in sex-role reversed species, and sex-related differences in the detection and use of MH-odor cues are expected to influence the intensity of sexual selection in such species. The seahorse, Hippocampus abdominalis, has an exceptionally highly developed form of male parental care, with female-female competition and male mate choice. Here, we demonstrate that the sex-role reversed seahorse has a single MH class II beta-chain gene and that the diversity of the seahorse MHIIβ locus and its pattern of variation are comparable to those detected in species with conventional sex roles. Despite the presence of only a single gene copy, intralocus MHIIβ allelic diversity in this species exceeds that observed in species with multiple copies of this locus. The MHIIβ locus of the seahorse exhibits a novel expression domain in the male brood pouch. The high variation found at the seahorse MHIIβ gene indicates that sex-role reversed species are capable of maintaining the high MHC diversity typical in most vertebrates.Whether such species have evolved the capacity to use MH-odor cues during mate choice is presently being investigated using mate choice experiments. If this possibility can be rejected, such systems would offer an exceptional opportunity to study the effects of natural selection in isolation, providing powerful comparative models for understanding the

  13. The impact of sex-role reversal on the diversity of the major histocompatibility complex: Insights from the seahorse (Hippocampus abdominalis

    Directory of Open Access Journals (Sweden)

    Wilson Anthony B

    2011-05-01

    Full Text Available Abstract Background Both natural and sexual selection are thought to influence genetic diversity, but the study of the relative importance of these two factors on ecologically-relevant traits has traditionally focused on species with conventional sex-roles, with male-male competition and female-based mate choice. With its high variability and significance in both immune function and olfactory-mediated mate choice, the major histocompatibility complex (MHC/MH is an ideal system in which to evaluate the relative contributions of these two selective forces to genetic diversity. Intrasexual competition and mate choice are both reversed in sex-role reversed species, and sex-related differences in the detection and use of MH-odor cues are expected to influence the intensity of sexual selection in such species. The seahorse, Hippocampus abdominalis, has an exceptionally highly developed form of male parental care, with female-female competition and male mate choice. Results Here, we demonstrate that the sex-role reversed seahorse has a single MH class II beta-chain gene and that the diversity of the seahorse MHIIβ locus and its pattern of variation are comparable to those detected in species with conventional sex roles. Despite the presence of only a single gene copy, intralocus MHIIβ allelic diversity in this species exceeds that observed in species with multiple copies of this locus. The MHIIβ locus of the seahorse exhibits a novel expression domain in the male brood pouch. Conclusions The high variation found at the seahorse MHIIβ gene indicates that sex-role reversed species are capable of maintaining the high MHC diversity typical in most vertebrates. Whether such species have evolved the capacity to use MH-odor cues during mate choice is presently being investigated using mate choice experiments. If this possibility can be rejected, such systems would offer an exceptional opportunity to study the effects of natural selection in isolation

  14. First comparative characterization of three distinct ferritin subunits from a teleost: Evidence for immune-responsive mRNA expression and iron depriving activity of seahorse (Hippocampus abdominalis) ferritins.

    Science.gov (United States)

    Oh, Minyoung; Umasuthan, Navaneethaiyer; Elvitigala, Don Anushka Sandaruwan; Wan, Qiang; Jo, Eunyoung; Ko, Jiyeon; Noh, Gyeong Eon; Shin, Sangok; Rho, Sum; Lee, Jehee

    2016-02-01

    Ferritins play an indispensable role in iron homeostasis through their iron-withholding function in living beings. In the current study, cDNA sequences of three distinct ferritin subunits, including a ferritin H, a ferritin M, and a ferritin L, were identified from big belly seahorse, Hippocampus abdominalis, and molecularly characterized. Complete coding sequences (CDS) of seahorse ferritin H (HaFerH), ferritin M (HaFerM), and ferritin L (HaFerL) subunits were comprised of 531, 528, and 522 base pairs (bp), respectively, which encode polypeptides of 177, 176, and 174 amino acids, respectively, with molecular masses of ∼20-21 kDa. Our in silico analyses demonstrate that these three ferritin subunits exhibit the typical characteristics of ferritin superfamily members including iron regulatory elements, domain signatures, and reactive centers. The coding sequences of HaFerH, M, and L were cloned and the corresponding proteins were overexpressed in a bacterial system. Recombinantly expressed HaFer proteins demonstrated detectable in vivo iron sequestrating (ferroxidase) activity, consistent with their putative iron binding capability. Quantification of the basal expression of these three HaFer sequences in selected tissues demonstrated a gene-specific ubiquitous spatial distribution pattern, with abundance of mRNA in HaFerM in the liver and predominant expression of HaFerH and HaFerL in blood. Interestingly, the basal expression of all three ferritin genes was found to be significantly modulated against pathogenic stress mounted by lipopolysaccharides (LPS), poly I:C, Streptococcus iniae, and Edwardsiella tarda. Collectively, our findings suggest that the three HaFer subunits may be involved in iron (II) homeostasis in big belly seahorse and that they are important in its host defense mechanisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Insights into the multifunctional role of natural killer enhancing factor-A (NKEF-A/Prx1) in big-belly seahorse (Hippocampus abdominalis): DNA protection, insulin reduction, H2O2 scavenging, and immune modulation activity.

    Science.gov (United States)

    Godahewa, G I; Perera, N C N; Lee, Jehee

    2018-02-05

    Natural killer enhancing factor A (NKEF-A), also known as peroxiredoxin 1 (Prx1), is a well-known antioxidant involved in innate immunity. Although NKEF-A/Prx1 has been studied in different fish species, the present study broadens the knowledge of NKEF-A gene in terms of molecular structure, function, and immune responses in fish species. Hippocampus abdominalis NKEF-A (HaNKEF-A) cDNA encoded a putative protein of 198 amino acids containing a thioredoxin_2 domain, VCP motifs, and three conserved cysteine residues including peroxidatic and resolving cysteines. Amino acid sequence comparison and phylogenetic breakdown showed the higher sequence identity and closer evolutionary position of HaNKEF-A to those of other fish counterparts. A recombinant protein of HaNKEF-A was shown to i) protect supercoiled DNA against mixed catalyzed oxidation, ii) reduce insulin disulfide bonds, and iii) scavenge extracellular H 2 O 2 . Results of in vitro assays demonstrated the concentration dependent antioxidant function of recombinant HaNKEF-A. In addition, qPCR assessments revealed that the HaNKEF-A transcripts were constitutively expressed in fourteen tissues with the highest expression in liver. As an innate immune response, HaNKEF-A transcripts were up-regulated in liver post injection of LPS, Edwardsiella tarda, Streptococcus iniae, and polyinosinic-polycytidylic acid. Thus, HaNKEF-A can safeguards big-belly seahorse from oxidative damage and pathogenic infections. This study provides insight into the functions of NKEF-A/Prx1 in fish species. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Copper-zinc-superoxide dismutase (CuZnSOD), an antioxidant gene from seahorse (Hippocampus abdominalis); molecular cloning, sequence characterization, antioxidant activity and potential peroxidation function of its recombinant protein.

    Science.gov (United States)

    Perera, N C N; Godahewa, G I; Lee, Jehee

    2016-10-01

    Copper-zinc-superoxide dismutase (CuZnSOD) from Hippocampus abdominalis (HaCuZnSOD) is a metalloenzyme which belongs to the ubiquitous family of SODs. Here, we determined the characteristic structural features of HaCuZnSOD, analyzed its evolutionary relationships, and identified its potential immune responses and biological functions in relation to antioxidant defense mechanisms in the seahorse. The gene had a 5' untranslated region (UTR) of 67 bp, a coding sequence of 465 bp and a 3' UTR of 313 bp. The putative peptide consists of 154 amino acids. HaCuZnSOD had a predicted molecular mass of 15.94 kDa and a theoretical pI value of 5.73, which is favorable for copper binding activity. In silico analysis revealed that HaCuZnSOD had a prominent Cu-Zn_superoxide_dismutase domain, two Cu/Zn signature sequences, a putative N-glycosylation site, and several active sites including Cu(2+) and Zn(2+) binding sites. The three dimensional structure indicated a β-sheet barrel with 8 β-sheets and two short α-helical regions. Multiple alignment analyses revealed many conserved regions and active sites among its orthologs. The highest amino acid identity to HaCuZnSOD was found in Siniperca chuatsi (87.4%), while Maylandia zebra shared a close relationship in the phylogenetic analysis. Functional assays were performed to assess the antioxidant, biophysical and biochemical properties of overexpressed recombinant (r) HaCuZnSOD. A xanthine/XOD assay gave optimum results at pH 9 and 25 °C indicating these may be the best conditions for its antioxidant action in the seahorse. An MTT assay and flow cytometry confirmed that rHaCuZnSOD showed peroxidase activity in the presence of HCO3(-). In all the functional assays, the level of antioxidant activity of rHaCuZnSOD was concentration dependent; metal ion supplementation also increased its activity. The highest mRNA expressional level of HaCuZnSOD was found in blood. Temporal assessment under pathological stress showed a delay

  17. Aneurysm of the A. hepatica propria as cause of Angina abdominalis

    International Nuclear Information System (INIS)

    Rieser, R.; Hauger, W.

    1988-01-01

    The aetiology of a. hepatica aneurysm can be manifold. Among all the complications, rupture of the vessel is the most dangerous one. We report on a case which was noticed clinically due to an angina abdominalis. In this paper we outline the symptoms, all diagnostic steps and the therapeutic approach. (orig.) [de

  18. Penggunaan Antibiotika Pada Pasien Anak Penderita Tifus Abdominalis Di Instalasi Rawat Inap RSUD Banyumas Periode Agustus 2009 – Juli 2010

    OpenAIRE

    Sapmaimy, Desy; Kusumawati, Anis; Hapsari, Indri

    2011-01-01

    Typhus abdominalis is the systemic infectious disease with significant morbidity almost throughout the year. It is still a common health problem in developing countries, especially children in Indonesia. The objective of this study is to investigate the utilization of antibiotics in hospitalized children patient with Typhus abdominalis at RSUD Banyumas during the period of August 2009-July 2010. This was a retrospective study using medical record data that analysed and compared with therapy s...

  19. New aspects in the diagnosis of angina abdominalis using digital substraction angiography

    International Nuclear Information System (INIS)

    Mahmalat, M.O.; Beyer, H.K.

    1985-01-01

    Selective intra-arterial digital substraction angiography (DSA) is important in the demonstration of the visceral abdominal vessels in angina-abdominalis patients. DSA allows to accurately determine the location of stenoses, vascular occlusions or plaque formations as does conventional angiography; in addition, it provides for simultaneous direct observation which is a major advantage over the conventional technique since suspected lesions can be better focussed in several planes. (orig.) [de

  20. Direct detection of male quality can facilitate the evolution of female choosiness and indicators of good genes: Evolution across a continuum of indicator mechanisms.

    Science.gov (United States)

    Dhole, Sumit; Stern, Caitlin A; Servedio, Maria R

    2018-04-01

    The evolution of mating displays as indicators of male quality has been the subject of extensive theoretical and empirical research for over four decades. Research has also addressed the evolution of female mate choice favoring such indicators. Yet, much debate still exists about whether displays can evolve through the indirect benefits of female mate choice. Here, we use a population genetic model to investigate how the extent to which females can directly detect male quality influences the evolution of female choosiness and male displays. We use a continuum framework that incorporates indicator mechanisms that are traditionally modeled separately. Counter to intuition, we find that intermediate levels of direct detection of male quality can facilitate, rather than impede, the evolution of female choosiness and male displays in broad regions of this continuum. We examine how this evolution is driven by selective forces on genetic quality and on the display, and find that direct detection of male quality results in stronger indirect selection favoring female choosiness. Our results imply that displays maybe more likely to evolve when female choosiness has already evolved to discriminate perceptible forms of male quality. They also highlight the importance of considering general female choosiness, as well as preference, in studies of "good genes." © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  1. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri.

    Science.gov (United States)

    Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V P; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species.

  2. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri

    OpenAIRE

    Shrestha, Govinda; Skovg?rd, Henrik; Reddy, Gadi V. P.; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitizatio...

  3. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri.

    Directory of Open Access Journals (Sweden)

    Govinda Shrestha

    Full Text Available Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38% compared to N. ribisnigri (30%. Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84% and female-biased sex ratio (> 83% were found irrespective of the aphid species.

  4. Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri

    Science.gov (United States)

    Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V. P.; Steenberg, Tove; Enkegaard, Annie

    2017-01-01

    Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species. PMID:28854232

  5. The role of selected soil fauna as predators of Apethymus abdominalis Lep. (Hymenoptera: Tenthredinidae) in oak forests in the District Caiuti, Romania

    Science.gov (United States)

    C. Ciornei; N. Popa; L. Ciuca; C. Rang

    2003-01-01

    The present study was initiated in 2001 in the oak forests from Trotus valley (Forest District Caiucti - Bacau, Romania) which were heavily infested by oak sawflies Apethymus abdominalis Lep. (Hymenoptera: Tenthredinidae), in order to understand better the role of soil-inhabitating predators in population regulation of this pest.

  6. Neoplasia of captive yellow sea horses (Hippocampus kuda) and weedy sea dragons (Phyllopteryx taeniolatus).

    Science.gov (United States)

    LePage, Véronique; Dutton, Christopher J; Kummrow, Maya; McLelland, David J; Young, Karrie; Lumsden, John S

    2012-03-01

    Syngnathidae is the family of fish that includes sea horses, pipefish, and sea dragons. To date, only a single publication has described neoplasia in syngnathids, a fibrosarcoma of the brood pouch in an aquarium-reared lined sea horse (Hippocampus erectus). From 1998 until 2010, the Toronto Zoo submitted 172 syngnathids for postmortem; species included the spotted or yellow sea horse (Hippocampus kuda), the pot-bellied sea horse (Hippocampus abdominalis) and the weedy sea dragon (Phyllopteryx taeniolatus). Seven neoplasms and two neoplastic-like lesions were identified from these cases. Under light microscopy, the neoplasms had morphological characteristics of a cardiac rhabdomyosarcoma, renal adenocarcinoma, renal adenoma, renal round cell tumors, which were likely lymphomas, exocrine pancreatic carcinoma, and intestinal carcinoma. Of these neoplasms, four had clear evidence of metastasis: the pancreatic and intestinal carcinomas and both round cell tumors. As syngnathids are highly fastidious animals, they can be difficult to maintain in captivity. In order to improve their husbandry, preventative and palliative care, as well as treatment, it is important to investigate and document the types of diseases affecting syngnathids.

  7. Choosy moral punishers.

    Directory of Open Access Journals (Sweden)

    Christine Clavien

    Full Text Available The punishment of social misconduct is a powerful mechanism for stabilizing high levels of cooperation among unrelated individuals. It is regularly assumed that humans have a universal disposition to punish social norm violators, which is sometimes labelled "universal structure of human morality" or "pure aversion to social betrayal". Here we present evidence that, contrary to this hypothesis, the propensity to punish a moral norm violator varies among participants with different career trajectories. In anonymous real-life conditions, future teachers punished a talented but immoral young violinist: they voted against her in an important music competition when they had been informed of her previous blatant misconduct toward fellow violin students. In contrast, future police officers and high school students did not punish. This variation among socio-professional categories indicates that the punishment of norm violators is not entirely explained by an aversion to social betrayal. We suggest that context specificity plays an important role in normative behaviour; people seem inclined to enforce social norms only in situations that are familiar, relevant for their social category, and possibly strategically advantageous.

  8. Hippocampus at 25

    Science.gov (United States)

    Eichenbaum, Howard; Amaral, David G.; Buffalo, Elizabeth A.; Buzsáki, György; Cohen, Neal; Davachi, Lila; Frank, Loren; Heckers, Stephan; Morris, Richard G. M.; Moser, Edvard I.; Nadel, Lynn; O'Keefe, John; Preston, Alison; Ranganath, Charan; Silva, Alcino; Witter, Menno

    2017-01-01

    The journal Hippocampus has passed the milestone of 25 years of publications on the topic of a highly studied brain structure, and its closely associated brain areas. In a recent celebration of this event, a Boston memory group invited 16 speakers to address the question of progress in understanding the hippocampus that has been achieved. Here we present a summary of these talks organized as progress on four main themes: (1) Understanding the hippocampus in terms of its interactions with multiple cortical areas within the medial temporal lobe memory system, (2) understanding the relationship between memory and spatial information processing functions of the hippocampal region, (3) understanding the role of temporal organization in spatial and memory processing by the hippocampus, and (4) understanding how the hippocampus integrates related events into networks of memories. PMID:27399159

  9. Hippocampus discovery First steps

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    Full Text Available The first steps of the discovery, and the main discoverers, of the hippocampus are outlined. Arantius was the first to describe a structure he named "hippocampus" or "white silkworm". Despite numerous controversies and alternate designations, the term hippocampus has prevailed until this day as the most widely used term. Duvernoy provided an illustration of the hippocampus and surrounding structures, considered the first by most authors, which appeared more than one and a half century after Arantius' description. Some authors have identified other drawings and texts which they claim predate Duvernoy's depiction, in studies by Vesalius, Varolio, Willis, and Eustachio, albeit unconvincingly. Considering the definition of the hippocampal formation as comprising the hippocampus proper, dentate gyrus and subiculum, Arantius and Duvernoy apparently described the gross anatomy of this complex. The pioneering studies of Arantius and Duvernoy revealed a relatively small hidden formation that would become one of the most valued brain structures.

  10. Evaluation of the internal oblique, external oblique, and transversus abdominalis muscles in patients with ankylosing spondylitis: an ultrasonographic study.

    Science.gov (United States)

    Üşen, Ahmet; Kuran, Banu; Yılmaz, Figen; Aksu, Neşe; Erçalık, Cem

    2017-11-01

    The objectives of the study are to compare abdominal muscle thickness in ankylosing spondylitis (AS) patients with healthy subjects and determine the factors affecting these muscle thickness. Thirty-five male patients with a previous diagnosis of AS according to the Modified New York criteria and a control group consisting of 35 healthy male individuals were included in this cross-sectional and case-control study. Thicknesses of the internal oblique (IO), external oblique (EO), and transversus abdominalis (TrA) muscles were measured with ultrasound (US). AS patients were classified according to the International Physical Activity Questionnaire (IPAQ). There were 35 AS patients with a mean age of 35.17 ± 8.05 years and 35 healthy subjects with a mean age 32.57 ± 7.05 years. No significant difference was observed between the groups in terms of abdominal muscle thicknesses (p > 0.005). When the AS patients were classified according to the IPAQ scores, thicknesses of the IO and TrA muscles were significantly lower in patients who had the low level of IPAQ scores (p < 0.05). In the light of our first and preliminary results, muscle thickness of the IO, EO, and TrA muscles were similar in AS patients to healthy subjects. However, AS patients who had lower level of physical activity have also reduced thickness of IO and TrA muscles.

  11. Two distinct CXC chemokine receptors (CXCR3 and CXCR4) from the big-belly seahorse Hippocampus abdominalis: Molecular perspectives and immune defensive role upon pathogenic stress.

    Science.gov (United States)

    Priyathilaka, Thanthrige Thiunuwan; Oh, Minyoung; Bathige, S D N K; De Zoysa, Mahanama; Lee, Jehee

    2017-06-01

    CXC chemokine receptor 3 (CXCR3) and 4 (CXCR4) are members of the seven transmembrane G protein coupled receptor family, involved in pivotal physiological functions. In this study, seahorse CXCR3 and CXCR4 (designated as HaCXCR3 and HaCXCR4) cDNA sequences were identified from the transcriptome library and subsequently molecularly characterized. HaCXCR3 and HaCXCR4 encoded 363 and 373 amino acid long polypeptides, respectively. The HaCXCR3 and HaCXCR4 deduced proteins have typical structural features of chemokine receptors, including seven transmembrane domains and a G protein coupled receptors family 1 profile with characteristic DRY motifs. Amino acid sequence comparison and phylogenetic analysis of these two CXC chemokine receptors revealed a close relationship to their corresponding teleost counterparts. Quantitative real time PCR analysis revealed that HaCXCR3 and HaCXCR4 were ubiquitously expressed in all the tested tissues, with highest expression levels in blood cells. The seahorse blood cells and kidney HaCXCR3 and HaCXCR4 mRNA expressions were differently modulated when challenged with Edwardsiella tarda, Streptococcus iniae, lipopolysaccharide, and polyinosinic:polycytidylic acid, confirming their involvement in post immune responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. The hippocampus - pictorial essay

    International Nuclear Information System (INIS)

    Whan, A.; Mitchell, L.A.

    2002-01-01

    Full text: We aim to demonstrate the anatomy and pathology of the hippocampus. It is important that radiologists distinguish normal and abnormal hippocampal hippocampal MR appearances, since hippocampal sclerosis is the commonest cause of surgically treatable temporal lobe epilepsy. The detailed anatomy of the hippocampus is reviewed and correlated with normal MR appearances. Our radiology database was reviewed to determine both common and unusual pathologies affecting the hippocampus. Most scans were performed for our large Comprehensive Epilepsy Program, for investigation of epilepsy of possible seizures. Less frequent indications included memory loss (acute or chronic), stroke, headache, and altered conscious state. Hippocampal sclerosis was the commonest MR abnormality. This was occasionally bilateral or associated with other pathology. Other common findings included mild hippocampal asymmetry, bilateral atrophy, or normal variants such as choroid fissure cysts. Other pathologies included cortical developmental malformations, infarction, posttraumatic gliosis, herpes, simplex encephalitis, paraneoplastic limbic encephalitis, vascular malformations, sarcoidosis, benign tumours such as gangliogliomas and dysembyoplastic neuroepithelial tumours (DNET) and malignant tumours. The hippocampus has a complex anatomy visible on high resolution MRI. In the clinical context of epilepsy, hippocampal sclerosis is an important pathology, but a range of conditions may affect the hippocampus, readily demonstrated by MRI. Copyright (2002) Blackwell Science Pty Ltd

  13. Serotonin Receptors in Hippocampus

    Science.gov (United States)

    Berumen, Laura Cristina; Rodríguez, Angelina; Miledi, Ricardo; García-Alcocer, Guadalupe

    2012-01-01

    Serotonin is an ancient molecular signal and a recognized neurotransmitter brainwide distributed with particular presence in hippocampus. Almost all serotonin receptor subtypes are expressed in hippocampus, which implicates an intricate modulating system, considering that they can be localized as autosynaptic, presynaptic, and postsynaptic receptors, even colocalized within the same cell and being target of homo- and heterodimerization. Neurons and glia, including immune cells, integrate a functional network that uses several serotonin receptors to regulate their roles in this particular part of the limbic system. PMID:22629209

  14. Unusual arrangement and behaviour of the sex chromosomes of Aphodius (Agolius abdominalis Bonelli, 1812, and comparison with A. (A. bonvouloiri Harold, 1860 (Coleoptera: Aphodiidae

    Directory of Open Access Journals (Sweden)

    Robert Angus

    2009-12-01

    Full Text Available Aphodius abdominalis Bonelli, 1812 is shown to have a karyotype comprising nine pairs of autosomes and sex chromosomes which are X0 (male, XX (female. At first metaphase of meiosis the X chromosome is linked to an autosomal bivalent by a darkly staining area of the cytoplasm, resembling the Xy p arrangement typical of Aphodius species, but giving nine, rather than 10, elements in the nucleus. C-banding, which shows the centromeres, confirms this unusual arrangement. A. bonvouloiri, the only other known species of subgenus Agolius Mulsant et Rey, 1869, has a male karyotype with nine pairs of autosomes and Xy sex chromosomes. No preparations of its meiosis are available.

  15. Job shop fails choosy nurses.

    Science.gov (United States)

    1993-10-13

    Only 181 people have used the Clearing House set up to find jobs for redundant London nurses. And almost a quarter have rejected the posts which it says are suitable for them, with 21 per cent of employers turning down candidates selected by the initiative.

  16. The hippocampus and visual perception

    Science.gov (United States)

    Lee, Andy C. H.; Yeung, Lok-Kin; Barense, Morgan D.

    2012-01-01

    In this review, we will discuss the idea that the hippocampus may be involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes. This suggestion is based on a number of recent neuropsychological and functional neuroimaging studies that have demonstrated that the hippocampus is involved in the visual discrimination of complex spatial scene stimuli. We argue that these findings cannot be explained by long-term memory or working memory processing or, in the case of patient findings, dysfunction beyond the medial temporal lobe (MTL). Instead, these studies point toward a role for the hippocampus in higher-order spatial perception. We suggest that the hippocampus processes complex conjunctions of spatial features, and that it may be more appropriate to consider the representations for which this structure is critical, rather than the cognitive processes that it mediates. PMID:22529794

  17. The hippocampus and visual perception

    Directory of Open Access Journals (Sweden)

    Andy C. H. Lee

    2012-04-01

    Full Text Available In this review, we will discuss the idea that the hippocampus may be involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes. This suggestion is based on a number of recent neuropsychological and functional neuroimaging studies that have demonstrated that the hippocampus is involved in the visual discrimination of complex spatial scene stimuli. We argue that these findings cannot be explained by long-term memory or working memory processing or, in the case of patient findings, dysfunction beyond the medial temporal lobe. Instead, these studies point towards a role for the hippocampus in higher-order spatial perception. We suggest that the hippocampus processes complex conjunctions of spatial features, and that it may be more appropriate to consider the representations for which this structure is critical, rather than the cognitive processes that it mediates.

  18. Stress, memory, and the hippocampus.

    Science.gov (United States)

    Wingenfeld, Katja; Wolf, Oliver T

    2014-01-01

    Stress hormones, i.e. cortisol in human and cortisone in rodents, influence a wide range of cognitive functions, including hippocampus-based declarative memory performance. Cortisol enhances memory consolidation, but impairs memory retrieval. In this context glucocorticoid receptor sensitivity and hippocampal integrity play an important role. This review integrates findings on the relationships between the hypothalamus-pituitary-adrenal (HPA) axis, one of the main coordinators of the stress response, hippocampus, and memory. Findings obtained in healthy participants will be compared with selected mental disorders, including major depressive disorder (MDD), posttraumatic stress disorder (PTSD), and borderline personality disorder (BPD). These disorders are characterized by alterations of the HPA axis and hippocampal dysfunctions. Interestingly, the acute effects of stress hormones on memory in psychiatric patients are different from those found in healthy humans. While cortisol administration has failed to affect memory retrieval in patients with MDD, patients with PTSD and BPD have been found to show enhanced rather than impaired memory retrieval after hydrocortisone. This indicates an altered sensitivity to stress hormones in these mental disorders. © 2014 S. Karger AG, Basel

  19. Hippocampus in health and disease: An overview

    Directory of Open Access Journals (Sweden)

    Kuljeet Singh Anand

    2012-01-01

    Full Text Available Hippocampus is a complex brain structure embedded deep into temporal lobe. It has a major role in learning and memory. It is a plastic and vulnerable structure that gets damaged by a variety of stimuli. Studies have shown that it also gets affected in a variety of neurological and psychiatric disorders. In last decade or so, lot has been learnt about conditions that affect hippocampus and produce changes ranging from molecules to morphology. Progresses in radiological delineation, electrophysiology, and histochemical characterization have made it possible to study this archicerebral structure in greater detail. Present paper attempts to give an overview of hippocampus, both in health and diseases.

  20. Working memory and the hippocampus.

    Science.gov (United States)

    Baddeley, Alan; Jarrold, Christopher; Vargha-Khadem, Faraneh

    2011-12-01

    A number of studies suggest an important role for the hippocampus in tasks involving visuospatial or relational working memory. We test the generality of this proposal across tasks using a battery designed to investigate the various components of working memory, studying the working memory performance of Jon, who shows a bilateral reduction in hippocampal volume of approximately 50%, comparing him to a group of 48 college students. We measure performance on four complex working memory span measures based on combining visuospatial and verbal storage with visuospatial or verbal concurrent processing as well as measuring Jon's ability to carry out the component storage and processing aspects of these tasks. Jon performed at a consistently high level across our range of tasks. Possible reasons for the apparent disparity between our own findings and earlier studies showing a hippocampal deficit are discussed in terms of both the potential differences in the demands placed on relational memory and of the proposed distinction between egocentric and allocentric visuospatial processing.

  1. Chewing Maintains Hippocampus-Dependent Cognitive Function.

    Science.gov (United States)

    Chen, Huayue; Iinuma, Mitsuo; Onozuka, Minoru; Kubo, Kin-Ya

    2015-01-01

    Mastication (chewing) is important not only for food intake, but also for preserving and promoting the general health. Recent studies have showed that mastication helps to maintain cognitive functions in the hippocampus, a central nervous system region vital for spatial memory and learning. The purpose of this paper is to review the recent progress of the association between mastication and the hippocampus-dependent cognitive function. There are multiple neural circuits connecting the masticatory organs and the hippocampus. Both animal and human studies indicated that cognitive functioning is influenced by mastication. Masticatory dysfunction is associated with the hippocampal morphological impairments and the hippocampus-dependent spatial memory deficits, especially in elderly. Mastication is an effective behavior for maintaining the hippocampus-dependent cognitive performance, which deteriorates with aging. Therefore, chewing may represent a useful approach in preserving and promoting the hippocampus-dependent cognitive function in older people. We also discussed several possible mechanisms involved in the interaction between mastication and the hippocampal neurogenesis and the future directions for this unique fascinating research.

  2. Why avoid the hippocampus? A comprehensive review

    International Nuclear Information System (INIS)

    Gondi, Vinai; Tome, Wolfgang A.; Mehta, Minesh P.

    2010-01-01

    In this review article, we provide a detailed and comprehensive discussion of the rationale for using modern IMRT techniques to spare the subgranular zone of the hippocampus during cranial irradiation. We review the literature on neurocognitive effects of cranial irradiation; discuss clinical and preclinical data associating damage to neural progrenitor cells located in subgranular zone of the hippocampus with radiation-induced neurocognitive decline, specifically in terms of short-term memory formation and recall; and present a review of our pilot investigations into the feasibility and risks of sparing the subgranular zone of the hippocampus during whole-brain radiotherapy for brain metastases. We also introduce our phase II cooperative group clinical trial (RTOG 0933) designed to prospectively evaluate the postulated neurocognitive benefit of hippocampal subgranular zone sparing and scheduled to open in 2010.

  3. Andrographolide Stimulates Neurogenesis in the Adult Hippocampus

    Directory of Open Access Journals (Sweden)

    Lorena Varela-Nallar

    2015-01-01

    Full Text Available Andrographolide (ANDRO is a labdane diterpenoid component of Andrographis paniculata widely used for its anti-inflammatory properties. We have recently determined that ANDRO is a competitive inhibitor of glycogen synthase kinase-3β (GSK-3β, a key enzyme of the Wnt/β-catenin signaling cascade. Since this signaling pathway regulates neurogenesis in the adult hippocampus, we evaluated whether ANDRO stimulates this process. Treatment with ANDRO increased neural progenitor cell proliferation and the number of immature neurons in the hippocampus of 2- and 10-month-old mice compared to age-matched control mice. Moreover, ANDRO stimulated neurogenesis increasing the number of newborn dentate granule neurons. Also, the effect of ANDRO was evaluated in the APPswe/PS1ΔE9 transgenic mouse model of Alzheimer’s disease. In these mice, ANDRO increased cell proliferation and the density of immature neurons in the dentate gyrus. Concomitantly with the increase in neurogenesis, ANDRO induced the activation of the Wnt signaling pathway in the hippocampus of wild-type and APPswe/PS1ΔE9 mice determined by increased levels of β-catenin, the inactive form of GSK-3β, and NeuroD1, a Wnt target gene involved in neurogenesis. Our findings indicate that ANDRO stimulates neurogenesis in the adult hippocampus suggesting that this drug could be used as a therapy in diseases in which neurogenesis is affected.

  4. Does the endangered Knysna seahorse, Hippocampus capensis ...

    African Journals Online (AJOL)

    Abstract. The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour- intensive. The aim of this study was to establish if Knynsa seahorses are ...

  5. Coordinating different representations in the hippocampus

    Czech Academy of Sciences Publication Activity Database

    Kelemen, Eduard; Fenton, A.A.

    2016-01-01

    Roč. 129, Mar 2016 (2016), s. 50-59 ISSN 1074-7427 R&D Projects: GA ČR(CZ) GA14-03627S Institutional support: RVO:67985823 Keywords : dynamic functional grouping * multiple representations * cognitive control * hippocampus * overdispersion Subject RIV: FH - Neurology Impact factor: 3.543, year: 2016

  6. Endogenous synthesis of corticosteroids in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Shimpei Higo

    Full Text Available BACKGROUND: Brain synthesis of steroids including sex-steroids is attracting much attention. The endogenous synthesis of corticosteroids in the hippocampus, however, has been doubted because of the inability to detect deoxycorticosterone (DOC synthase, cytochrome P450(c21. METHODOLOGY/PRINCIPAL FINDINGS: The expression of P450(c21 was demonstrated using mRNA analysis and immmunogold electron microscopic analysis in the adult male rat hippocampus. DOC production from progesterone (PROG was demonstrated by metabolism analysis of (3H-steroids. All the enzymes required for corticosteroid synthesis including P450(c21, P450(2D4, P450(11β1 and 3β-hydroxysteroid dehydrogenase (3β-HSD were localized in the hippocampal principal neurons as shown via in situ hybridization and immunoelectron microscopic analysis. Accurate corticosteroid concentrations in rat hippocampus were determined by liquid chromatography-tandem mass spectrometry. In adrenalectomized rats, net hippocampus-synthesized corticosterone (CORT and DOC were determined to 6.9 and 5.8 nM, respectively. Enhanced spinogenesis was observed in the hippocampus following application of low nanomolar (10 nM doses of CORT for 1 h. CONCLUSIONS/SIGNIFICANCE: These results imply the complete pathway of corticosteroid synthesis of 'pregnenolone →PROG→DOC→CORT' in the hippocampal neurons. Both P450(c21 and P450(2D4 can catalyze conversion of PROG to DOC. The low nanomolar level of CORT synthesized in hippocampal neurons may play a role in modulation of synaptic plasticity, in contrast to the stress effects by micromolar CORT from adrenal glands.

  7. Traveling Theta Waves in the Human Hippocampus

    Science.gov (United States)

    Zhang, Honghui

    2015-01-01

    The hippocampal theta oscillation is strongly correlated with behaviors such as memory and spatial navigation, but we do not understand its specific functional role. One hint of theta's function came from the discovery in rodents that theta oscillations are traveling waves that allow parts of the hippocampus to simultaneously exhibit separate oscillatory phases. Because hippocampal theta oscillations in humans have different properties compared with rodents, we examined these signals directly using multielectrode recordings from neurosurgical patients. Our findings confirm that human hippocampal theta oscillations are traveling waves, but also show that these oscillations appear at a broader range of frequencies compared with rodents. Human traveling waves showed a distinctive pattern of spatial propagation such that there is a consistent phase spread across the hippocampus regardless of the oscillations' frequency. This suggests that traveling theta oscillations are important functionally in humans because they coordinate phase coding throughout the hippocampus in a consistent manner. SIGNIFICANCE STATEMENT We show for the first time in humans that hippocampal theta oscillations are traveling waves, moving along the length of the hippocampus in a posterior–anterior direction. The existence of these traveling theta waves is important for understanding hippocampal neural coding because they cause neurons at separate positions in the hippocampus to experience different theta phases simultaneously. The theta phase that a neuron measures is a key factor in how that cell represents behavioral information. Therefore, the existence of traveling theta waves indicates that, to fully understand how a hippocampal neuron represents information, it is vital to also account for that cell's location in addition to conventional measures of neural activity. PMID:26354915

  8. Impact of video games on plasticity of the hippocampus.

    Science.gov (United States)

    West, G L; Konishi, K; Diarra, M; Benady-Chorney, J; Drisdelle, B L; Dahmani, L; Sodums, D J; Lepore, F; Jolicoeur, P; Bohbot, V D

    2017-08-08

    The hippocampus is critical to healthy cognition, yet results in the current study show that action video game players have reduced grey matter within the hippocampus. A subsequent randomised longitudinal training experiment demonstrated that first-person shooting games reduce grey matter within the hippocampus in participants using non-spatial memory strategies. Conversely, participants who use hippocampus-dependent spatial strategies showed increased grey matter in the hippocampus after training. A control group that trained on 3D-platform games displayed growth in either the hippocampus or the functionally connected entorhinal cortex. A third study replicated the effect of action video game training on grey matter in the hippocampus. These results show that video games can be beneficial or detrimental to the hippocampal system depending on the navigation strategy that a person employs and the genre of the game.Molecular Psychiatry advance online publication, 8 August 2017; doi:10.1038/mp.2017.155.

  9. Neurobiological toxicity of radiation in hippocampus

    Energy Technology Data Exchange (ETDEWEB)

    Son, Yeong Hoon; Kim, Joong Sun [Research center, Dongnam institute of radiological and Medical Sciences (DIRAMS), Busan (Korea, Republic of); Kim, Sung Ho; Moon, Chang Jong [College of Veterinary Medicine, Chonnam National University, Gwangju (Korea, Republic of)

    2014-11-15

    Ionizing radiation affects multiple organs, which differ in their apparent response. Nevertheless, the adult brain is less vulnerable to radiation than other radiosensitive organs. Clinically, patients receive partial large-field or whole-brain irradiation for cancer treatment yearly, long-term survivors increases, and thus, radiation induced side effects, including cognitive impairment, will become a major health problem. Although the most commonly reported noxious effects of irradiation occur via damage to DNA and consequent disruption of protein synthesis, there are also specific effects on biochemical pathways that have indirect effects on DNA transcription. The hippocampus dependent memory dysfunction is consistent with the changes in neurogenesis after 1 and 3 dyas after irradiation. At 30 and 90 days following irradiation, mice displayed significant depression-like behaviors. Hippocampal dysfunction during the chronic phase following cranial irradiation may be associated with decreases in the neurogenesis and synaptic plasticity related signals, concomitant with microglial reduction in the hippocampus.

  10. Development of short-snouted seahorse (Hippocampus hippocampus, L. 1758): osteological and morphological aspects.

    Science.gov (United States)

    Novelli, B; Otero-Ferrer, F; Socorro, J A; Caballero, M J; Segade-Botella, A; Molina Domínguez, L

    2017-06-01

    Information about early development after male release lags behind studies of juveniles and adult seahorses, and newborn seahorses, similar in shape to adults, are considered juveniles or fry. During early life, Hippocampus hippocampus present behavioural (shift in habitat, from planktonic to benthic) and morphological changes; for this reasons, the aims of this study are to define the stage of development of H. hippocampus after they are expelled from the male brood pouch and to establish direct or indirect development through an osteological analysis. The ossification process was studied in 120 individuals, from their release to 30 days after birth. To analyse the osteological development, Alcian Blue-Alizarin Red double staining technique for bone and cartilage was adapted to this species. At birth, H. hippocampus presents a mainly cartilaginous structure that ossifies in approximately 1 month. The bony armour composed of bony rings and plates develops in 10 days. The caudal fin, a structure absent in juveniles and adult seahorses, is present at birth and progressively disappears with age. The absence of adult osteological structure in newborns, like coronet, bony rings and plates, head spines and components allowing tail prehensile abilities, suggests a metamorphosis before the juvenile stage. During the indirect development, the metamorphic stage started inside brood pouch and followed outside and leads up to reconsider the status of H. hippocampus newborns.

  11. The investigation of biometric characteristics of seahorse species [Hippocampus hippocampus (Linnaeus,

    Directory of Open Access Journals (Sweden)

    Şule Gürkan

    2015-12-01

    Full Text Available Bu çalışma, İzmir Körfezi’nde dağılım gösteren Syngnathidae familyasına ait denizatı türlerini ve bu türlerin biyometrik özelliklerini belirlemek amacıyla yapılmıştır. Şubat 2000 tarihinde bölgede avlanan balıkçılardan 29 adet Hippocampus hippocampus, ve 200 adet Hippocampus guttulatus örneği temin edilmiştir. Elde edilen örneklerin metrik ve meristik özellikleri ve boy-ağırlık ilişkileri ile boy ve ağırlık frekans değerleri verilmiştir

  12. When is the hippocampus involved in recognition memory?

    OpenAIRE

    Barker, Gareth R. I.; Warburton, Elizabeth C.

    2011-01-01

    The role of the hippocampus in recognition memory is controversial. Recognition memory judgments may be made using different types of information, including object familiarity, an object's spatial location, or when an object was encountered. Experiment 1 examined the role of the hippocampus in recognition memory tasks that required the animals to use these different types of mnemonic information. Rats with bilateral cytotoxic lesions in the hippocampus or perirhinal or prefrontal cortex were ...

  13. Circadian Oscillations within the Hippocampus Support Hippocampus-dependent Memory Processing

    Directory of Open Access Journals (Sweden)

    Kristin Lynn Eckel-Mahan

    2012-04-01

    Full Text Available The ability to sustain memories over long periods of time, sometimes even a lifetime, is one of the most remarkable properties of the brain. Much knowledge has been gained over the past few decades regarding the molecular correlates of memory formation. Once a memory is forged, however, the molecular events that provide permanence are as of yet unclear. Studies in multiple organisms have revealed that circadian rhythmicity is important for the formation, stability, and recall of memories [1]. The neuronal events that provide this link need to be explored further. This article will discuss the findings related to the circadian regulation of memory-dependent processes in the hippocampus. Specifically, the circadian-controlled MAP kinase and cAMP signal transduction pathway plays critical roles in the consolidation of hippocampus-dependent memory. A series of studies have revealed the circadian oscillation of this pathway within the hippocampus, an activity that is absent in memory-deficient, transgenic mice lacking Ca2+-stimulated adenylyl cyclases. Interference with these oscillations proceeding the cellular memory consolidation period impairs the persistence of hippocampus-dependent memory. These data suggest that the persistence of long-term memories may depend upon reactivation of this signal transduction pathway in the hippocampus during the circadian cycle. New data reveals the dependence of hippocampal oscillation in MAPK activity on the SCN, again underscoring the importance of this region in maintaining the circadian physiology of memory. Finally, the downstream ramification of these oscillations in terms of gene expression and epigenetics should be considered, as emerging evidence is pointing strongly to a circadian link between epigenetics and long term synaptic plasticity.

  14. Hippocampus and amygdala volumes in patients with vaginismus.

    Science.gov (United States)

    Atmaca, Murad; Baykara, Sema; Ozer, Omer; Korkmaz, Sevda; Akaslan, Unsal; Yildirim, Hanefi

    2016-06-22

    To compare hippocampus and amygdala volumes of patients with vaginismus with those of healthy control subjects. Magnetic resonance imaging was performed on ten patients with vaginismus and ten control subjects matched for age and gender. Volumes of the hippocampus and amygdala were blindly measured. We found that the mean right amygdala volume of patients with vaginismus were smaller than that of the healthy controls. With regard to hippocampus volumes, the mean left and right hippocampus volumes were smaller than those of the healthy controls. Our present findings suggest that there have been hippocampus and amygdala structural abnormalities in patients with vaginismus. These changes provide the notion that vaginismus may be a fear-related condition.

  15. Creating a false memory in the hippocampus.

    Science.gov (United States)

    Ramirez, Steve; Liu, Xu; Lin, Pei-Ann; Suh, Junghyup; Pignatelli, Michele; Redondo, Roger L; Ryan, Tomás J; Tonegawa, Susumu

    2013-07-26

    Memories can be unreliable. We created a false memory in mice by optogenetically manipulating memory engram-bearing cells in the hippocampus. Dentate gyrus (DG) or CA1 neurons activated by exposure to a particular context were labeled with channelrhodopsin-2. These neurons were later optically reactivated during fear conditioning in a different context. The DG experimental group showed increased freezing in the original context, in which a foot shock was never delivered. The recall of this false memory was context-specific, activated similar downstream regions engaged during natural fear memory recall, and was also capable of driving an active fear response. Our data demonstrate that it is possible to generate an internally represented and behaviorally expressed fear memory via artificial means.

  16. Association between income and the hippocampus.

    Directory of Open Access Journals (Sweden)

    Jamie L Hanson

    2011-05-01

    Full Text Available Facets of the post-natal environment including the type and complexity of environmental stimuli, the quality of parenting behaviors, and the amount and type of stress experienced by a child affects brain and behavioral functioning. Poverty is a type of pervasive experience that is likely to influence biobehavioral processes because children developing in such environments often encounter high levels of stress and reduced environmental stimulation. This study explores the association between socioeconomic status and the hippocampus, a brain region involved in learning and memory that is known to be affected by stress. We employ a voxel-based morphometry analytic framework with region of interest drawing for structural brain images acquired from participants across the socioeconomic spectrum (n = 317. Children from lower income backgrounds had lower hippocampal gray matter density, a measure of volume. This finding is discussed in terms of disparities in education and health that are observed across the socioeconomic spectrum.

  17. Resistance exercise improves hippocampus-dependent memory

    Directory of Open Access Journals (Sweden)

    R.C. Cassilhas

    2012-12-01

    Full Text Available It has been demonstrated that resistance exercise improves cognitive functions in humans. Thus, an animal model that mimics this phenomenon can be an important tool for studying the underlying neurophysiological mechanisms. Here, we tested if an animal model for resistance exercise was able to improve the performance in a hippocampus-dependent memory task. In addition, we also evaluated the level of insulin-like growth factor 1/insulin growth factor receptor (IGF-1/IGF-1R, which plays pleiotropic roles in the nervous system. Adult male Wistar rats were divided into three groups (N = 10 for each group: control, SHAM, and resistance exercise (RES. The RES group was submitted to 8 weeks of progressive resistance exercise in a vertical ladder apparatus, while the SHAM group was left in the same apparatus without exercising. Analysis of a cross-sectional area of the flexor digitorum longus muscle indicated that this training period was sufficient to cause muscle fiber hypertrophy. In a step-through passive avoidance task (PA, the RES group presented a longer latency than the other groups on the test day. We also observed an increase of 43 and 94% for systemic and hippocampal IGF-1 concentration, respectively, in the RES group compared to the others. A positive correlation was established between PA performance and systemic IGF-1 (r = 0.46, P < 0.05. Taken together, our data indicate that resistance exercise improves the hippocampus-dependent memory task with a concomitant increase of IGF-1 level in the rat model. This model can be further explored to better understand the effects of resistance exercise on brain functions.

  18. Life history and ecology of the elusive European short-snouted seahorse Hippocampus hippocampus.

    Science.gov (United States)

    Curtis, J M R; Santos, S V; Nadeau, J L; Gunn, B; Bigney Wilner, K; Balasubramanian, H; Overington, S; Lesage, C-M; D'entremont, J; Wieckowski, K

    2017-12-01

    To improve the understanding of the life history and ecology of one of Europe's most elusive fishes, the short-snouted seahorse Hippocampus hippocampus, data from wild populations in a shallow coastal lagoon in southern Portugal were analysed. The data were collected from 17 tagged seahorses on a focal-study grid as well as from >350 seahorses encountered during underwater visual surveys and a fishery-independent study using beach seines. These populations of settled juveniles and adults had a mean population density of 0·009 m -2 . During the study period (2000-2004), reproduction peaked in July and August. Juveniles recruited to the lagoon at c. 66 mm standard length (L S ) and 0·5 years of age and established small home ranges (0·8 to 18·2 m 2 ). First reproduction was estimated at 100 mm and 1 year of age. Based on a fitted von Bertalanffy model, H. hippocampus grew quickly (growth coefficient K = 0·93) to a maximum theoretical size L ∞  = 150 mm and have a maximum lifespan of c. 3·2 years. Courtship behaviours were consistent with the maintenance of pair bonds and males brooded multiple batches of young per year. Estimated annual reproductive output averaged 871 young (±632). Together these analyses provide the first life-history parameters for this species and indicate that H. hippocampus bears characteristics of opportunist and intermediate strategists. Such populations are predicted to exhibit large fluctuations in abundance, making them vulnerable to extended periods of poor recruitment. © 2017 The Fisheries Society of the British Isles.

  19. Role of the hippocampus in memory functioning: modern view

    Directory of Open Access Journals (Sweden)

    D. O. Assonov

    2017-12-01

    Full Text Available The purpose of this review was to develop the comprehensive conception of the hippocampus role in the functioning of human memory, based on data obtained by analysis of the latest scientific literature on the topic and make recommendations for further ways of researches in this topic. The scientific literature of the last 5 years on the role of the hippocampus in memory functioning was analyzed. Based on the reviewed literature, we made the next conclusions: the hippocampus is an extremely important for memory structure with various connections for different types of memory; the hippocampus is affected by a variety of substances, most studied now are glucocorticosteroids, whose effect on memory differs depending on the start time of action; the hippocampus volume in mental disorders affecting memory is less than normal, which makes it an important diagnostic criterion; at the moment, various promising methods that can help in the therapy of PTSD, depression, phobias and other disorders associated with memory impairment and based on the knowledge of the hippocampus for the treatment of memory disorders are being developed. Based on these conclusions and data, which were analyzed, we offered the following recommendations: to implement the hippocampal function examination in the diagnostics of mental disorders, which are accompanied by a violation of its work; to use the size of the hippocampus as one of the prognostic factors for the severity of the memory-associated disorders and the therapy progress; to carefully investigate the difference in the effect of various psychotherapies and pharmacotherapies on the hippocampus to determine exactly which of the therapies is the most morphologically reasonable; to find out how significant the decrease in the hippocampal volume is for the memory functioning; to use pathogenetically and morphologically based methods to improve the function of the hippocampus in the treatment of disorders that are

  20. Alterations in right posterior hippocampus in early blind individuals

    DEFF Research Database (Denmark)

    Chebat, Daniel-Robert; Chen, Jan-Kai; Schneider, Fabien

    2007-01-01

    This study compares hippocampal volumes of early blind and sex/age-matched sighted controls through volumetric and localization analyses. Early blind individuals showed a significantly smaller right posterior hippocampus compared with controls. No differences in total hippocampal volumes were fou...... of the posterior hippocampus in early blind individuals suggests the implication of this region in visual spatial memory. Udgivelsesdato: 2007-Mar-5......This study compares hippocampal volumes of early blind and sex/age-matched sighted controls through volumetric and localization analyses. Early blind individuals showed a significantly smaller right posterior hippocampus compared with controls. No differences in total hippocampal volumes were found...

  1. Somatostatin receptors in rat hippocampus: localization to intrinsic neurons

    International Nuclear Information System (INIS)

    Palacios, J.M.; Reubi, J.C.; Maurer, R.

    1986-01-01

    The effect of neurotoxic chemical and electrolytical lesions on somatostatin (SS) receptor binding in the septo-hippocampal afferents, pyramidal and granule cells of the rat hippocampus was examined by autoradiography using the stable SS analogue 125 I-204-090 as radioligand. Electrolytical lesions of the septum did not result in modification of SS binding in the hippocampus. In contrast, both granule cell lesion with colchicine and pyramidal or pyramidal and granule cell lesions with increasing kainic acid doses did result in a specific decrease of binding in the dentate gyrus and hippocampus (CA 1 and CA 3 ). These results suggest that SS receptors in the hippocampus are probably associated with elements from intrinsic neurons. (Author)

  2. Hippocampus and amygdala morphology in attention-deficit/hyperactivity disorder

    DEFF Research Database (Denmark)

    Plessen, Kerstin J; Bansal, Ravi; Zhu, Hongtu

    2006-01-01

    CONTEXT: Limbic structures are implicated in the genesis of attention-deficit/hyperactivity disorder (ADHD) by the presence of mood and cognitive disturbances in affected individuals and by elevated rates of mood disorders in family members of probands with ADHD. OBJECTIVE: To study the morphology...... of the hippocampus and amygdala in children with ADHD. DESIGN: A cross-sectional case-control study of the hippocampus and amygdala using anatomical magnetic resonance imaging. SETTINGS: University research institute. PATIENTS: One hundred fourteen individuals aged 6 to 18 years, 51 with combined-type ADHD and 63...... healthy controls. MAIN OUTCOME MEASURES: Volumes and measures of surface morphology for the hippocampus and amygdala. RESULTS: The hippocampus was larger bilaterally in the ADHD group than in the control group (t = 3.35; P

  3. Role of the hippocampus in contextual modulation of fear extinction

    Institute of Scientific and Technical Information of China (English)

    Lingzhi Kong; Xihong Wu; Liang Li

    2008-01-01

    Fear extinction is an important form of emotional learning, and affects neural plasticity. Cue fear extinction is a classical form of inhibitory learning that can be used as an exposure-based treatment for phobia, because the long-term extinction memory produced during cue fear extinction can limit the over-expression of fear. The expression of this inhibitory memory partly depends on the context in which the extinction learning occurs. Studies such as transient inhibition, electrophysiology and brain imaging have proved that the hippocampus - an important structure in the limbic system - facilitates memory retrieval by contextual cues.Mediation of the hippocampus-medial prefrontal lobe circuit may be the neurobiological basis of this process.This article has reviewed the role of the hippocampus in the learning and retrieval of fear extinction.Contextual modulation of fear extinction may rely on a neural network consisting of the hippocampus, the medial prefrontal cortex and the amygdala.

  4. Hippocampus, delay discounting, and vicarious trial-and-error.

    Science.gov (United States)

    Bett, David; Murdoch, Lauren H; Wood, Emma R; Dudchenko, Paul A

    2015-05-01

    In decision-making, an immediate reward is usually preferred to a delayed reward, even if the latter is larger. We tested whether the hippocampus is necessary for this form of temporal discounting, and for vicarious trial-and-error at the decision point. Rats were trained on a recently developed, adjustable delay-discounting task (Papale et al. (2012) Cogn Affect Behav Neurosci 12:513-526), which featured a choice between a small, nearly immediate reward, and a larger, delayed reward. Rats then received either hippocampus or sham lesions. Animals with hippocampus lesions adjusted the delay for the larger reward to a level similar to that of sham-lesioned animals, suggesting a similar valuation capacity. However, the hippocampus lesion group spent significantly longer investigating the small and large rewards in the first part of the sessions, and were less sensitive to changes in the amount of reward in the large reward maze arm. Both sham- and hippocampus-lesioned rats showed a greater amount of vicarious trial-and-error on trials in which the delay was adjusted. In a nonadjusting version of the delay discounting task, animals with hippocampus lesions showed more variability in their preference for a larger reward that was delayed by 10 s compared with sham-lesioned animals. To verify the lesion behaviorally, rat were subsequently trained on a water maze task, and rats with hippocampus lesions were significantly impaired compared with sham-lesioned animals. The findings on the delay discounting tasks suggest that damage to the hippocampus may impair the detection of reward magnitude. © 2014 Wiley Periodicals, Inc.

  5. Sleep-dependent directional coupling between human neocortex and hippocampus.

    Science.gov (United States)

    Wagner, Tobias; Axmacher, Nikolai; Lehnertz, Klaus; Elger, Christian E; Fell, Jürgen

    2010-02-01

    Complex interactions between neocortex and hippocampus are the neural basis of memory formation. Two-step theories of memory formation suggest that initial encoding of novel information depends on the induction of rapid plasticity within the hippocampus, and is followed by a second sleep-dependent step of memory consolidation. These theories predict information flow from the neocortex into the hippocampus during waking state and in the reverse direction during sleep. However, experimental evidence that interactions between hippocampus and neocortex have a predominant direction which reverses during sleep rely on cross-correlation analysis of data from animal experiments and yielded inconsistent results. Here, we investigated directional coupling in intracranial EEG data from human subjects using a phase-modeling approach which is well suited to reveal functional interdependencies in oscillatory data. In general, we observed that the anterior hippocampus predominantly drives nearby and remote brain regions. Surprisingly, however, the influence of neocortical regions on the hippocampus significantly increased during sleep as compared to waking state. These results question the standard model of hippocampal-neocortical interactions and suggest that sleep-dependent consolidation is accomplished by an active retrieval of hippocampal information by the neocortex. Copyright 2009 Elsevier Srl. All rights reserved.

  6. Glucose, relational memory, and the hippocampus.

    Science.gov (United States)

    Stollery, Brian; Christian, Leonie

    2015-06-01

    Many studies suggest that glucose can temporarily enhance hippocampal-dependent memories. As the hippocampus plays a key role in associative learning, we examined the influence of glucose on verbal paired associate memory. This study examines how glucose modifies performance on a relational memory task by examining its influence on learning, subsequent forgetting and relearning. A selective reminding procedure was used to show high and low imagability paired associates to 80 participants, who were seen twice. On the first session, they received 25 g glucose pre-learning, 25 g glucose post-learning or placebo. On the second session, 1 week later, they received 25 g glucose or placebo. Cued-recall was evaluated after each learning trial, 1 week later to assess forgetting and after an opportunity to relearn the material forgotten. Glucose did not influence paired associate acquisition. Those given glucose pre-learning tended to forget less material the following week, and independently, glucose at retrieval facilitated cued-recall. Both forms of facilitation were equally apparent on low and high imagability pairs. The benefit of glucose pre-learning was eliminated once the paired associates had been seen again, but the benefit of glucose at retrieval extended into the second relearning trial. The discussion considers the cognitive processes and hippocampal basis for paired associate learning and retention and the implications for glucose's mode of action. It is proposed that glucose during encoding serves to make the delayed memories initially more available, whereas its influence during delayed retrieval makes available memories temporarily more accessible.

  7. Evolution of the hippocampus in reptiles and birds.

    Science.gov (United States)

    Striedter, Georg F

    2016-02-15

    Although the hippocampus is structurally quite different among reptiles, birds, and mammals, its function in spatial memory is said to be highly conserved. This is surprising, given that structural differences generally reflect functional differences. Here I review this enigma in some detail, identifying several evolutionary changes in hippocampal cytoarchitecture and connectivity. I recognize a lepidosaurid pattern of hippocampal organization (in lizards, snakes, and the tuatara Sphenodon) that differs substantially from the pattern of organization observed in the turtle/archosaur lineage, which includes crocodilians and birds. Although individual subdivisions of the hippocampus are difficult to homologize between these two patterns, both lack a clear homolog of the mammalian dentate gyrus. The strictly trilaminar organization of the ancestral amniote hippocampus was gradually lost in the lineage leading to birds, and birds expanded the system of intrahippocampal axon collaterals, relative to turtles and lizards. These expanded collateral axon branches resemble the extensive collaterals in CA3 of the mammalian hippocampus but probably evolved independently of them. Additional examples of convergent evolution between birds and mammals are the loss of direct inputs to the hippocampus from the primary olfactory cortex and the general expansion of telencephalic regions that communicate reciprocally with the hippocampus. Given this structural convergence, it seems likely that some similarities in the function of the hippocampus between birds and mammals, notably its role in the ability to remember many different locations without extensive training, likewise evolved convergently. The currently available data do not allow for a strong test of this hypothesis, but the hypothesis itself suggests some promising new research directions. © 2015 Wiley Periodicals, Inc.

  8. Episodic Memory and Beyond: The Hippocampus and Neocortex in Transformation.

    Science.gov (United States)

    Moscovitch, Morris; Cabeza, Roberto; Winocur, Gordon; Nadel, Lynn

    2016-01-01

    The last decade has seen dramatic technological and conceptual changes in research on episodic memory and the brain. New technologies, and increased use of more naturalistic observations, have enabled investigators to delve deeply into the structures that mediate episodic memory, particularly the hippocampus, and to track functional and structural interactions among brain regions that support it. Conceptually, episodic memory is increasingly being viewed as subject to lifelong transformations that are reflected in the neural substrates that mediate it. In keeping with this dynamic perspective, research on episodic memory (and the hippocampus) has infiltrated domains, from perception to language and from empathy to problem solving, that were once considered outside its boundaries. Using the component process model as a framework, and focusing on the hippocampus, its subfields, and specialization along its longitudinal axis, along with its interaction with other brain regions, we consider these new developments and their implications for the organization of episodic memory and its contribution to functions in other domains.

  9. Interplay of hippocampus and prefrontal cortex in memory

    Science.gov (United States)

    Preston, Alison R.; Eichenbaum, Howard

    2013-01-01

    Recent studies on the hippocampus and the prefrontal cortex have considerably advanced our understanding of the distinct roles of these brain areas in the encoding and retrieval of memories, and of how they interact in the prolonged process by which new memories are consolidated into our permanent storehouse of knowledge. These studies have led to a new model of how the hippocampus forms and replays memories and how the prefrontal cortex engages representations of the meaningful contexts in which related memories occur, as well as how these areas interact during memory retrieval. Furthermore, they have provided new insights into how interactions between the hippocampus and prefrontal cortex support the assimilation of new memories into pre-existing networks of knowledge, called schemas, and how schemas are modified in this process as the foundation of memory consolidation. PMID:24028960

  10. Hippocampus is place of interaction between unconscious and conscious memories.

    Directory of Open Access Journals (Sweden)

    Marc Alain Züst

    Full Text Available Recent evidence suggests that humans can form and later retrieve new semantic relations unconsciously by way of hippocampus-the key structure also recruited for conscious relational (episodic memory. If the hippocampus subserves both conscious and unconscious relational encoding/retrieval, one would expect the hippocampus to be place of unconscious-conscious interactions during memory retrieval. We tested this hypothesis in an fMRI experiment probing the interaction between the unconscious and conscious retrieval of face-associated information. For the establishment of unconscious relational memories, we presented subliminal (masked combinations of unfamiliar faces and written occupations ("actor" or "politician". At test, we presented the former subliminal faces, but now supraliminally, as cues for the reactivation of the unconsciously associated occupations. We hypothesized that unconscious reactivation of the associated occupation-actor or politician-would facilitate or inhibit the subsequent conscious retrieval of a celebrity's occupation, which was also actor or politician. Depending on whether the reactivated unconscious occupation was congruent or incongruent to the celebrity's occupation, we expected either quicker or delayed conscious retrieval process. Conscious retrieval was quicker in the congruent relative to a neutral baseline condition but not delayed in the incongruent condition. fMRI data collected during subliminal face-occupation encoding confirmed previous evidence that the hippocampus was interacting with neocortical storage sites of semantic knowledge to support relational encoding. fMRI data collected at test revealed that the facilitated conscious retrieval was paralleled by deactivations in the hippocampus and neocortical storage sites of semantic knowledge. We assume that the unconscious reactivation has pre-activated overlapping relational representations in the hippocampus reducing the neural effort for conscious

  11. Impact of schizophrenia on anterior and posterior hippocampus during memory for complex scenes

    Directory of Open Access Journals (Sweden)

    J.D. Ragland

    2017-01-01

    Conclusions: Results suggest a gradient of hippocampal dysfunction in which posterior hippocampus – which is necessary for processing fine-grained spatial relationships – is underactive, and anterior hippocampus – which may process context more globally - is overactive.

  12. Roles of the basolateral amygdala and hippocampus in social recognition

    NARCIS (Netherlands)

    Gispen, W.H.; Maaswinkel, H.; Baars, A.M.; Spruijt, B.M.

    1996-01-01

    Lesions of the amygdala or hippocampus have a large impact on social behavior of rats. In this study we investigated whether a social recognition test was also affected by those lesions. An NMDA-induced lesion of the basolateral amygdala did not impair the ability to distinguish a familiar from an

  13. Amygdala and hippocampus enlargement during adolescence in autism.

    NARCIS (Netherlands)

    Groen, W.B.; Teluij, M.; Buitelaar, J.K.; Tendolkar, I.

    2010-01-01

    OBJECTIVE: The amygdala and hippocampus are key components of the neural system mediating emotion perception and regulation and are thought to be involved in the pathophysiology of autism. Although some studies in children with autism suggest that there is an enlargement of amygdala and hippocampal

  14. Stress Effects on the Hippocampus: A Critical Review

    Science.gov (United States)

    Kim, Eun Joo; Pellman, Blake; Kim, Jeansok J.

    2015-01-01

    Uncontrollable stress has been recognized to influence the hippocampus at various levels of analysis. Behaviorally, human and animal studies have found that stress generally impairs various hippocampal-dependent memory tasks. Neurally, animal studies have revealed that stress alters ensuing synaptic plasticity and firing properties of hippocampal…

  15. The role of the hippocampus in recognition memory.

    Science.gov (United States)

    Bird, Chris M

    2017-08-01

    Many theories of declarative memory propose that it is supported by partially separable processes underpinned by different brain structures. The hippocampus plays a critical role in binding together item and contextual information together and processing the relationships between individual items. By contrast, the processing of individual items and their later recognition can be supported by extrahippocampal regions of the medial temporal lobes (MTL), particularly when recognition is based on feelings of familiarity without the retrieval of any associated information. These theories are domain-general in that "items" might be words, faces, objects, scenes, etc. However, there is mixed evidence that item recognition does not require the hippocampus, or that familiarity-based recognition can be supported by extrahippocampal regions. By contrast, there is compelling evidence that in humans, hippocampal damage does not affect recognition memory for unfamiliar faces, whilst recognition memory for several other stimulus classes is impaired. I propose that regions outside of the hippocampus can support recognition of unfamiliar faces because they are perceived as discrete items and have no prior conceptual associations. Conversely, extrahippocampal processes are inadequate for recognition of items which (a) have been previously experienced, (b) are conceptually meaningful, or (c) are perceived as being comprised of individual elements. This account reconciles findings from primate and human studies of recognition memory. Furthermore, it suggests that while the hippocampus is critical for binding and relational processing, these processes are required for item recognition memory in most situations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Incomplete inversion of the hippocampus - a common developmental anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Bajic, Dragan; Wang, Chen; Raininko, Raili [Uppsala University Hospital, Department of Radiology, Uppsala (Sweden); Kumlien, Eva; Mattsson, Peter [Uppsala University Hospital, Department of Neurology, Uppsala (Sweden); Lundberg, Staffan; Eeg-Olofsson, Orvar [Uppsala University Hospital, Department of Child Neurology, Uppsala (Sweden)

    2008-01-15

    Incomplete inversion of the hippocampus, an imperfect fetal development, has been described in patients with epilepsy or severe midline malformations. We studied this condition in a nonepileptic population without obvious developmental anomalies. We analyzed the coronal MR images of 50 women and 50 men who did not have epilepsy. Twenty of them were healthy volunteers and 80 were patients without obvious intracranial developmental anomalies, intracranial masses, hydrocephalus or any condition affecting the temporal lobes. If the entire hippocampus (the head could not be evaluated) were affected, the incomplete inversion was classified as total, otherwise as partial. Incomplete inversion of the hippocampus was found in 19/100 subjects (9 women, 10 men). It was unilateral, always on the left side, in 13 subjects (4 women, 9 men): 9 were of the total type, 4 were partial. It was bilateral in six subjects (five women, one man): four subjects had total types bilaterally, two had a combination of total and partial types. The collateral sulcus was vertically oriented in all subjects with a deviating hippocampal shape. We conclude that incomplete inversion of the hippocampus is not an unusual morphologic variety in a nonepileptic population without other obvious intracranial developmental anomalies. (orig.)

  17. Aerobic Exercise During Encoding Impairs Hippocampus-Dependent Memory.

    Science.gov (United States)

    Soga, Keishi; Kamijo, Keita; Masaki, Hiroaki

    2017-08-01

    We investigated how aerobic exercise during encoding affects hippocampus-dependent memory through a source memory task that assessed hippocampus-independent familiarity and hippocampus-dependent recollection processes. Using a within-participants design, young adult participants performed a memory-encoding task while performing a cycling exercise or being seated. The subsequent retrieval phase was conducted while sitting on a chair. We assessed behavioral and event-related brain potential measures of familiarity and recollection processes during the retrieval phase. Results indicated that source accuracy was lower for encoding with exercise than for encoding in the resting condition. Event-related brain potential measures indicated that the parietal old/new effect, which has been linked to recollection processing, was observed in the exercise condition, whereas it was absent in the rest condition, which is indicative of exercise-induced hippocampal activation. These findings suggest that aerobic exercise during encoding impairs hippocampus-dependent memory, which may be attributed to inefficient source encoding during aerobic exercise.

  18. Amygdala and Hippocampus Enlargement during Adolescence in Autism

    Science.gov (United States)

    Groen, Wouter; Teluij, Michelle; Buitelaar, Jan; Tendolkar, Indira

    2010-01-01

    Objective: The amygdala and hippocampus are key components of the neural system mediating emotion perception and regulation and are thought to be involved in the pathophysiology of autism. Although some studies in children with autism suggest that there is an enlargement of amygdala and hippocampal volume, findings in adolescence are sparse.…

  19. Adult Neurogenesis in the Mammalian Hippocampus: Why the Dentate Gyrus?

    Science.gov (United States)

    Drew, Liam J.; Fusi, Stefano; Hen, René

    2013-01-01

    In the adult mammalian brain, newly generated neurons are continuously incorporated into two networks: interneurons born in the subventricular zone migrate to the olfactory bulb, whereas the dentate gyrus (DG) of the hippocampus integrates locally born principal neurons. That the rest of the mammalian brain loses significant neurogenic capacity…

  20. Intrauterine growth restriction affects the preterm infant's hippocampus.

    Science.gov (United States)

    Lodygensky, Gregory A; Seghier, Mohammed L; Warfield, Simon K; Tolsa, Cristina Borradori; Sizonenko, Stephane; Lazeyras, François; Hüppi, Petra S

    2008-04-01

    The hippocampus is known to be vulnerable to hypoxia, stress, and undernutrition, all likely to be present in fetal intrauterine growth restriction (IUGR). The effect of IUGR in preterm infants on the hippocampus was studied using 3D magnetic resonance imaging at term-equivalent age Thirteen preterm infants born with IUGR after placental insufficiency were compared with 13 infants with normal intrauterine growth age matched for gestational age. The hippocampal structural differences were defined using voxel-based morphometry and manual segmentation. The specific neurobehavioral function was evaluated by the Assessment of Preterm Infants' Behavior at term and at 24 mo of corrected age by a Bayley Scales of Infant and Toddler Development. Voxel-based morphometry detected significant gray matter volume differences in the hippocampus between the two groups. This finding was confirmed by manual segmentation of the hippocampus with a reduction of hippocampal volume after IUGR. The hippocampal volume reduction was further associated with functional behavioral differences at term-equivalent age in all six subdomains of the Assessment of Preterm Infants' Behavior but not at 24 mo of corrected age. We conclude that hippocampal development in IUGR is altered and might result from a combination of maternal corticosteroid hormone exposure, hypoxemia, and micronutrient deficiency.

  1. Comparison of neurodegeneration between right and left hippocampus area in rats

    Directory of Open Access Journals (Sweden)

    Arezo Nahavandi

    2015-02-01

    Conclusion: Our study showed different manifestations of depression after UCMS. It showed that UCMS could lead to mental depression. This study showed that the right hippocampus was more sensitive to stress than the left hippocampus. In fact, UCMS resulted in depression. The study showed that the right hippocampus was more sensitive to stress than the left hippocampus. Therefore, the main function of the right hemisphere, which is adaptation to the new environment, is disturbed more.

  2. The vasopressin receptor of the blood-brain barrier in the rat hippocampus is linked to calcium signalling

    DEFF Research Database (Denmark)

    Hess, J.; Jensen, Claus V.; Diemer, Nils Henrik

    1991-01-01

    Neuropathology, vasopressin receptor, VI subtype, blood-brain barrier, cerebral endothelium, hippocampus, Fura-2......Neuropathology, vasopressin receptor, VI subtype, blood-brain barrier, cerebral endothelium, hippocampus, Fura-2...

  3. Dorsal hippocampus is necessary for visual categorization in rats.

    Science.gov (United States)

    Kim, Jangjin; Castro, Leyre; Wasserman, Edward A; Freeman, John H

    2018-02-23

    The hippocampus may play a role in categorization because of the need to differentiate stimulus categories (pattern separation) and to recognize category membership of stimuli from partial information (pattern completion). We hypothesized that the hippocampus would be more crucial for categorization of low-density (few relevant features) stimuli-due to the higher demand on pattern separation and pattern completion-than for categorization of high-density (many relevant features) stimuli. Using a touchscreen apparatus, rats were trained to categorize multiple abstract stimuli into two different categories. Each stimulus was a pentagonal configuration of five visual features; some of the visual features were relevant for defining the category whereas others were irrelevant. Two groups of rats were trained with either a high (dense, n = 8) or low (sparse, n = 8) number of category-relevant features. Upon reaching criterion discrimination (≥75% correct, on 2 consecutive days), bilateral cannulas were implanted in the dorsal hippocampus. The rats were then given either vehicle or muscimol infusions into the hippocampus just prior to various testing sessions. They were tested with: the previously trained stimuli (trained), novel stimuli involving new irrelevant features (novel), stimuli involving relocated features (relocation), and a single relevant feature (singleton). In training, the dense group reached criterion faster than the sparse group, indicating that the sparse task was more difficult than the dense task. In testing, accuracy of both groups was equally high for trained and novel stimuli. However, both groups showed impaired accuracy in the relocation and singleton conditions, with a greater deficit in the sparse group. The testing data indicate that rats encode both the relevant features and the spatial locations of the features. Hippocampal inactivation impaired visual categorization regardless of the density of the category-relevant features for

  4. Neural dynamics of the cognitive map in the hippocampus.

    Science.gov (United States)

    Wagatsuma, Hiroaki; Yamaguchi, Yoko

    2007-06-01

    The rodent hippocampus has been thought to represent the spatial environment as a cognitive map. In the classical theory, the cognitive map has been explained as a consequence of the fact that different spatial regions are assigned to different cell populations in the framework of rate coding. Recently, the relation between place cell firing and local field oscillation theta in terms of theta phase precession was experimentally discovered and suggested as a temporal coding mechanism leading to memory formation of behavioral sequences accompanied with asymmetric Hebbian plasticity. The cognitive map theory is apparently outside of the sequence memory view. Therefore, theoretical analysis is necessary to consider the biological neural dynamics for the sequence encoding of the memory of behavioral sequences, providing the cognitive map formation. In this article, we summarize the theoretical neural dynamics of the real-time sequence encoding by theta phase precession, called theta phase coding, and review a series of theoretical models with the theta phase coding that we previously reported. With respect to memory encoding functions, instantaneous memory formation of one-time experience was first demonstrated, and then the ability of integration of memories of behavioral sequences into a network of the cognitive map was shown. In terms of memory retrieval functions, theta phase coding enables the hippocampus to represent the spatial location in the current behavioral context even with ambiguous sensory input when multiple sequences were coded. Finally, for utilization, retrieved temporal sequences in the hippocampus can be available for action selection, through the process of reverting theta rhythm-dependent activities to information in the behavioral time scale. This theoretical approach allows us to investigate how the behavioral sequences are encoded, updated, retrieved and used in the hippocampus, as the real-time interaction with the external environment. It may

  5. File list: His.Neu.20.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available 300,SRX216301,SRX216299 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.20.AllAg.Hippocampus.bed ... ...His.Neu.20.AllAg.Hippocampus mm9 Histone Neural Hippocampus SRX1430120,SRX1430132,S

  6. File list: His.Neu.05.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available 455,SRX248469,SRX216301 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.05.AllAg.Hippocampus.bed ... ...His.Neu.05.AllAg.Hippocampus mm9 Histone Neural Hippocampus SRX1430132,SRX1430128,S

  7. File list: His.Neu.10.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available 302,SRX216299,SRX216301 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.10.AllAg.Hippocampus.bed ... ...His.Neu.10.AllAg.Hippocampus mm9 Histone Neural Hippocampus SRX1430128,SRX1430120,S

  8. File list: His.Neu.50.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available 07,SRX1430117,SRX216299 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.50.AllAg.Hippocampus.bed ... ...His.Neu.50.AllAg.Hippocampus mm9 Histone Neural Hippocampus SRX1430120,SRX1430132,S

  9. File list: ALL.Neu.50.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.50.AllAg.Hippocampus hg19 All antigens Neural Hippocampus SRX1177282,SRX117...7284,SRX1177283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.50.AllAg.Hippocampus.bed ...

  10. File list: ALL.Neu.05.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.05.AllAg.Hippocampus hg19 All antigens Neural Hippocampus SRX1177283,SRX117...7282,SRX1177284 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.05.AllAg.Hippocampus.bed ...

  11. File list: InP.Neu.05.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Neu.05.AllAg.Hippocampus mm9 Input control Neural Hippocampus SRX769389,SRX2484...70,SRX216313,SRX517457,SRX248471,SRX517454 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Neu.05.AllAg.Hippocampus.bed ...

  12. File list: Unc.Neu.20.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.20.AllAg.Hippocampus hg19 Unclassified Neural Hippocampus SRX1177282,SRX117...7284,SRX1177283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Neu.20.AllAg.Hippocampus.bed ...

  13. File list: Unc.Neu.50.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.50.AllAg.Hippocampus hg19 Unclassified Neural Hippocampus SRX1177282,SRX117...7284,SRX1177283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Neu.50.AllAg.Hippocampus.bed ...

  14. File list: InP.Neu.10.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Neu.10.AllAg.Hippocampus mm9 Input control Neural Hippocampus SRX248470,SRX7693...89,SRX216313,SRX517457,SRX517454,SRX248471 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Neu.10.AllAg.Hippocampus.bed ...

  15. File list: ALL.Neu.05.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.05.AllAg.Hippocampus mm9 All antigens Neural Hippocampus SRX1057076,SRX1057...17455,SRX248469,SRX216301 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.05.AllAg.Hippocampus.bed ...

  16. File list: Unc.Neu.05.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.05.AllAg.Hippocampus hg19 Unclassified Neural Hippocampus SRX1177283,SRX117...7282,SRX1177284 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Neu.05.AllAg.Hippocampus.bed ...

  17. File list: ALL.Neu.20.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.20.AllAg.Hippocampus hg19 All antigens Neural Hippocampus SRX1177282,SRX117...7284,SRX1177283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.20.AllAg.Hippocampus.bed ...

  18. File list: ALL.Neu.20.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.20.AllAg.Hippocampus mm9 All antigens Neural Hippocampus SRX1430120,SRX1430...16300,SRX216301,SRX216299 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.20.AllAg.Hippocampus.bed ...

  19. File list: InP.Neu.20.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Neu.20.AllAg.Hippocampus mm9 Input control Neural Hippocampus SRX248470,SRX7693...89,SRX517454,SRX517457,SRX216313,SRX248471 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Neu.20.AllAg.Hippocampus.bed ...

  20. File list: ALL.Neu.10.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.10.AllAg.Hippocampus hg19 All antigens Neural Hippocampus SRX1177282,SRX117...7284,SRX1177283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Neu.10.AllAg.Hippocampus.bed ...

  1. File list: Unc.Neu.10.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Neu.10.AllAg.Hippocampus hg19 Unclassified Neural Hippocampus SRX1177282,SRX117...7284,SRX1177283 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Neu.10.AllAg.Hippocampus.bed ...

  2. File list: InP.Neu.50.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Neu.50.AllAg.Hippocampus mm9 Input control Neural Hippocampus SRX248470,SRX7693...89,SRX517454,SRX517457,SRX216313,SRX248471 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Neu.50.AllAg.Hippocampus.bed ...

  3. File list: ALL.Neu.50.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.50.AllAg.Hippocampus mm9 All antigens Neural Hippocampus SRX1430120,SRX1430...0107,SRX1430117,SRX216299 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.50.AllAg.Hippocampus.bed ...

  4. File list: ALL.Neu.10.AllAg.Hippocampus [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Neu.10.AllAg.Hippocampus mm9 All antigens Neural Hippocampus SRX1430128,SRX1430...16302,SRX216299,SRX216301 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Neu.10.AllAg.Hippocampus.bed ...

  5. Historical and contemporary population genetic connectivity of the European short-snouted seahorse Hippocampus hippocampus and implications for management.

    Science.gov (United States)

    Woodall, L C; Koldewey, H J; Shaw, P W

    2011-06-01

    This first genetic study of Hippocampus hippocampus covers the species' entire geographic range and employs two mtDNA markers (control region and cytochrome b) to establish patterns of population structuring. A total of 255 specimens from 21 locations were used to obtain 89 concatenated haplotypes. The common haplotype was present in all but one population, however, most haplotypes were unique. The haplotype network had a star-like construction, suggesting expansion from a bottleneck event. F(ST) and AMOVA revealed population subdivision into three geographic regions (English Channel + Bay of Biscay, Mediterranean Sea + Atlantic Ocean Iberian coast + Macaronesian Islands, and West Africa) with barriers to gene flow indentified at Cape Finisterre and the Cape Verde frontal zone. Neutrality tests and nested clade analysis suggest a complex demographic history, with both historic events and contemporary processes shaping patterns of genetic differentiation. The genetic population subdivision detected in this study indicates that H. hippocampus should be managed as three separate units. This is especially pertinent as H. hippocampus populations within the West African region are the only ones known to be specifically targeted for exploitation. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  6. MORPHOLOGICAL CHANGES IN THE HIPPOCAMPUS OF RATS IN ACCELERATED AGING

    Directory of Open Access Journals (Sweden)

    K. Yu. Maksimova

    2014-01-01

    Full Text Available The aim of this work was the analysis of structural changes with age in the hippocampus of senescenceaccelerated OXYS rats when signs of accelerated brain aging are missing (age 14 days, developments (age 5 months, and active progresses (age 15 months. The study was performed on 15 OXYS rats and 15 Wistar rats (as a control. After dislocation, brains were dissected, fixed with 10% formalin, embedded in paraffin, and serially cut in coronal sections (5μm thickness. These sections were stained with Cresyl violet and examined with a photomicroscope (Carl Zeiss Axiostar plus, Germany. The total number of hippocampal pyramidal cells in the CA1, CA3 and the dentate gyrus regions were estimated in 14-dayold, 5and 15-month-old OXYS and Wistar rats (n = 5 on the 5 slices of each brain sections. The number of neurons with chromatolysis, hyperchromatic with darkly stained cytoplasm and shrunken neurons were calculated as degenerative neurons. The pictures obtained with the program Carl Zeiss Axio Vision 8.0 with increasing 10  100, determined the average area bodies and nuclei of neurons (mkm2. The significant structural changes of neurons in the CA1, CA3 and dentate gyrus regions of the hippocampus in OXYS rats at 5 month of age are revealed by light microscopy. This results indicates the early develop neurodegeneration in OXYS rats. The most pronounced morphological changes occur in the CA1 region of the hippocampus of OXYS rats and irreversible. The degenerative changes of neurons in the hippocampus increases by the age of 15 months. Morphometric analysis of the average area of bodies and the nuclei of hippocampal neurons in CA1, CA3 and the dentate gyrus regions of OXYS and Wistar rats at 14 days of age showed no significant interline differences. At 5 months of age in the CA1 region of the hippocampus of OXYS rats was determined a significantly lower average body size and nuclei of pyramidal neurons compared with Wistar rats. With age, these

  7. Choosy but not chaste: multiple mating in human females.

    Science.gov (United States)

    Scelza, Brooke A

    2013-01-01

    When Charles Darwin set out to relate his theory of evolution by natural selection to humans he discovered that a complementary explanation was needed to properly understand the great variation seen in human behavior. The resulting work, The Descent of Man and Selection in Relation to Sex, laid out the defining principles and evidence of sexual selection. In brief, this work is best known for illuminating the typically male strategy of intrasexual competition and the typically female response of intersexual choice. While these sexual stereotypes were first laid out by Darwin, they grew in importance when, years later, A. J. Bateman, in a careful study of Drosophila mating strategies, noted that multiple mating appeared to provide great benefit to male reproductive success, but to have no such effect on females. As a result, female choice soon became synonymous with being coy, and only males were thought to gain from promiscuous behavior. However, the last thirty years of research have served to question much of the traditional wisdom about sex differences proposed by Darwin and Bateman, illuminating the many ways that women (and females more generally) can and do engage in multiple mating. Copyright © 2013 Wiley Periodicals, Inc.

  8. Nicotinic mechanisms influencing synaptic plasticity in the hippocampus

    Institute of Scientific and Technical Information of China (English)

    Andon Nicholas PLACZEK; Tao A ZHANG; John Anthony DANI

    2009-01-01

    Nicotinic acetylcholine receptors (nAChRs) are expressed throughout the hippocampus, and nicotinic signaling plays an important role in neuronal function. In the context of learning and memory related behaviors associated with hippocampal function, a potentially significant feature of nAChR activity is the impact it has on synaptic plasticity. Synaptic plasticity in hippocampal neurons has long been considered a contributing cellular mechanism of learning and memory. These same kinds of cellular mechanisms are a factor in the development of nicotine addiction. Nicotinic signaling has been demonstrated by in vitro studies to affect synaptic plasticity in hippocampal neurons via multiple steps, and the signaling has also been shown to evoke synaptic plasticity in vivo. This review focuses on the nAChRs subtypes that contribute to hippocampal synaptic plasticity at the cellular and circuit level. It also considers nicotinic influences over long-term changes in the hippocampus that may contribute to addiction.

  9. Hippocampus sparing in whole-brain radiotherapy. A review

    International Nuclear Information System (INIS)

    Oskan, F.; Ganswindt, U.; Schwarz, S.B.; Manapov, F.; Belka, C.; Niyazi, M.

    2014-01-01

    Radiation treatment techniques for whole-brain radiation therapy (WBRT) have not changed significantly since development of the procedure. However, the recent development of novel techniques such as intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT) and helical tomotherapy, as well as an increasing body of evidence concerning neural stem cells (NSCs) have altered the conventional WBRT treatment paradigm. In this regard, hippocampus-sparing WBRT is a novel technique that aims to spare critical hippocampus regions without compromising tumour control. Published data on this new technique are limited to planning and feasibility studies; data on patient outcome are still lacking. However, several prospective trials to analyse the feasibility of this technique and to document clinical outcome in terms of reduced neurotoxicity are ongoing. (orig.) [de

  10. Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures

    Directory of Open Access Journals (Sweden)

    Bruno P. Carreira

    2015-01-01

    Full Text Available Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO. In these conditions, NO promotes proliferation of neural stem cells (NSC in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA induced seizure mouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.

  11. MOLECULAR BASIS OF LEARNING IN THE HIPPOCAMPUS AND THE AMYGDALA

    Directory of Open Access Journals (Sweden)

    Łukasz BIJOCH

    2015-12-01

    Full Text Available The hippocampus and the amygdala are structures of mammalian brain both involved in memorizing. However, they are responsible for different types of memory: the hippocampus is involved in creating and storing declarative engrams and the amygdala is engaged in some of non-declarative learning. During memorization, changes of synapses appear and it is believed that they encode information. Long-Term Potentiation (LTP and Long-Term Depression (LTD are two processes which provide to these changes which are called synaptic plasticity. LTP strengthens connections between neurons and because of that it is traditionally linked with learning. LTD as an opposite state is usually treated as forgetting. However, there are some evidences that it is true only for few types of non-declarative engrams. More sophisticated learning (like declarative learning requires cooperation of these processes. Review is focused on functions and detailed signaling pathways of processes of synaptic plasticity.

  12. Receptor autoradiography in the hippocampus of man and rat

    International Nuclear Information System (INIS)

    Zilles, K.

    1988-01-01

    This chapter deals with the following questions: regional distribution of binding sites for 5-HT, glutamate, and acetylcholine in Ammon's horn and the dentate gyrus of rat and human brain; comparison of receptor distribution and neuronal pathways with identified transmitters; correlation of region-specific densities between different receptors and receptor subtypes (colocalization of different receptors on the level of hippocampal layers) and comparison of receptor distribution in human and rat hippocampus

  13. Gene expression in cortex and hippocampus during acute pneumococcal meningitis

    Directory of Open Access Journals (Sweden)

    Wittwer Matthias

    2006-06-01

    Full Text Available Abstract Background Pneumococcal meningitis is associated with high mortality (~30% and morbidity. Up to 50% of survivors are affected by neurological sequelae due to a wide spectrum of brain injury mainly affecting the cortex and hippocampus. Despite this significant disease burden, the genetic program that regulates the host response leading to brain damage as a consequence of bacterial meningitis is largely unknown. We used an infant rat model of pneumococcal meningitis to assess gene expression profiles in cortex and hippocampus at 22 and 44 hours after infection and in controls at 22 h after mock-infection with saline. To analyze the biological significance of the data generated by Affymetrix DNA microarrays, a bioinformatics pipeline was used combining (i a literature-profiling algorithm to cluster genes based on the vocabulary of abstracts indexed in MEDLINE (NCBI and (ii the self-organizing map (SOM, a clustering technique based on covariance in gene expression kinetics. Results Among 598 genes differentially regulated (change factor ≥ 1.5; p ≤ 0.05, 77% were automatically assigned to one of 11 functional groups with 94% accuracy. SOM disclosed six patterns of expression kinetics. Genes associated with growth control/neuroplasticity, signal transduction, cell death/survival, cytoskeleton, and immunity were generally upregulated. In contrast, genes related to neurotransmission and lipid metabolism were transiently downregulated on the whole. The majority of the genes associated with ionic homeostasis, neurotransmission, signal transduction and lipid metabolism were differentially regulated specifically in the hippocampus. Of the cell death/survival genes found to be continuously upregulated only in hippocampus, the majority are pro-apoptotic, while those continuously upregulated only in cortex are anti-apoptotic. Conclusion Temporal and spatial analysis of gene expression in experimental pneumococcal meningitis identified potential

  14. Identification and characterization of PPAR? ligands in the hippocampus

    OpenAIRE

    Roy, Avik; Kundu, Madhuchhanda; Jana, Malabendu; Mishra, Rama K.; Yung, Yeni; Luan, Chi-Hao; Gonzalez, Frank J.; Pahan, Kalipada

    2016-01-01

    Peroxisome proliferator-activated receptor alpha (PPAR?) regulates hepatic fatty acid catabolism and mediates the metabolic response to starvation. Recently, we have found that PPAR? is constitutively activated in nuclei of hippocampal neurons and controls plasticity via direct transcriptional activation of CREB. Here, three endogenous ligands of PPAR?, 3-hydroxy-(2,2)-dimethyl butyrate, hexadecanamide, and 9-octadecenamide were discovered in mouse brain hippocampus. Mass spectrometric detect...

  15. Sleep in the human hippocampus: a stereo-EEG study.

    Directory of Open Access Journals (Sweden)

    Fabio Moroni

    Full Text Available BACKGROUND: There is compelling evidence indicating that sleep plays a crucial role in the consolidation of new declarative, hippocampus-dependent memories. Given the increasing interest in the spatiotemporal relationships between cortical and hippocampal activity during sleep, this study aimed to shed more light on the basic features of human sleep in the hippocampus. METHODOLOGY/PRINCIPAL FINDINGS: We recorded intracerebral stereo-EEG directly from the hippocampus and neocortical sites in five epileptic patients undergoing presurgical evaluations. The time course of classical EEG frequency bands during the first three NREM-REM sleep cycles of the night was evaluated. We found that delta power shows, also in the hippocampus, the progressive decrease across sleep cycles, indicating that a form of homeostatic regulation of delta activity is present also in this subcortical structure. Hippocampal sleep was also characterized by: i a lower relative power in the slow oscillation range during NREM sleep compared to the scalp EEG; ii a flattening of the time course of the very low frequencies (up to 1 Hz across sleep cycles, with relatively high levels of power even during REM sleep; iii a decrease of power in the beta band during REM sleep, at odds with the typical increase of power in the cortical recordings. CONCLUSIONS/SIGNIFICANCE: Our data imply that cortical slow oscillation is attenuated in the hippocampal structures during NREM sleep. The most peculiar feature of hippocampal sleep is the increased synchronization of the EEG rhythms during REM periods. This state of resonance may have a supportive role for the processing/consolidation of memory.

  16. Neural dynamics of the cognitive map in the hippocampus

    OpenAIRE

    Wagatsuma, Hiroaki; Yamaguchi, Yoko

    2007-01-01

    The rodent hippocampus has been thought to represent the spatial environment as a cognitive map. In the classical theory, the cognitive map has been explained as a consequence of the fact that different spatial regions are assigned to different cell populations in the framework of rate coding. Recently, the relation between place cell firing and local field oscillation theta in terms of theta phase precession was experimentally discovered and suggested as a temporal coding mechanism leading t...

  17. Visual cortex plasticity evokes excitatory alterations in the hippocampus

    Directory of Open Access Journals (Sweden)

    Marian Tsanov

    2009-11-01

    Full Text Available The integration of episodic sequences in the hippocampus is believed to occur during theta rhythm episodes, when cortico-hippocampal dialog results in reconfiguration of neuronal assemblies. As the visual cortex (VC is a major source of sensory information to the hippocampus, information processing in the cortex may affect hippocampal network oscillations, facilitating the induction of synaptic modifications. We investigated to what degree the field activity in the primary VC, elicited by sensory or electrical stimulation, correlates with hippocampal oscillatory and synaptic responsiveness, in freely behaving adult rats. We found that the spectral power of theta rhythm (4-10Hz in the dentate gyrus (DG, increases in parallel with high-frequency oscillations in layer 2/3 of the VC and that this correlation depends on the degree of exploratory activity. When we mimic robust thalamocortical activity by theta-burst application to dorsal lateral geniculate nucleus, a hippocampal theta increase occurs, followed by a persistent potentiation of the DG granule field population spike. Furthermore, the potentiation of DG neuronal excitability tightly correlates with the concurrently occurring VC plasticity. The concurrent enhancement of VC and DG activity is also combined with a highly negative synchronization between hippocampal and cortical low frequency oscillations. Exploration of familiar environment decreases the degree of this synchrony. Our data propose that novel visual information can induce high-power fluctuations in intrinsic excitability for both VC and hippocampus, potent enough to induce experience-dependent modulation of cortico-hippocampal connections. This interaction may comprise one of the endogenous triggers for long-term synaptic plasticity in the hippocampus.

  18. Caffeine alters proliferation of neuronal precursors in the adult hippocampus

    OpenAIRE

    Wentz, Christian T.; Magavi, Sanjay S.P.

    2009-01-01

    Neurogenesis continues through adulthood in the hippocampus and olfactory bulb of mammals. Adult neurogenesis has been implicated in learning and memory, and linked with depression. Hippocampal neurogenesis is increased in response to a number of stimuli, including exposure to an enriched environment, increased locomotor activity, and administration of antidepressants. Adult neurogenesis is depressed in response to aging, stress and sleep deprivation. Intriguingly, caffeine modulates a number...

  19. Anorexia Reduces GFAP+ Cell Density in the Rat Hippocampus.

    Science.gov (United States)

    Reyes-Haro, Daniel; Labrada-Moncada, Francisco Emmanuel; Varman, Durairaj Ragu; Krüger, Janina; Morales, Teresa; Miledi, Ricardo; Martínez-Torres, Ataúlfo

    2016-01-01

    Anorexia nervosa is an eating disorder observed primarily in young women. The neurobiology of the disorder is unknown but recently magnetic resonance imaging showed a volume reduction of the hippocampus in anorexic patients. Dehydration-induced anorexia (DIA) is a murine model that mimics core features of this disorder, including severe weight loss due to voluntary reduction in food intake. The energy supply to the brain is mediated by astrocytes, but whether their density is compromised by anorexia is unknown. Thus, the aim of this study was to estimate GFAP+ cell density in the main regions of the hippocampus (CA1, CA2, CA3, and dentate gyrus) in the DIA model. Our results showed that GFAP+ cell density was significantly reduced (~20%) in all regions of the hippocampus, except in CA1. Interestingly, DIA significantly reduced the GFAP+ cells/nuclei ratio in CA2 (-23%) and dentate gyrus (-48%). The reduction of GFAP+ cell density was in agreement with a lower expression of GFAP protein. Additionally, anorexia increased the expression of the intermediate filaments vimentin and nestin. Accordingly, anorexia increased the number of reactive astrocytes in CA2 and dentate gyrus more than twofold. We conclude that anorexia reduces the hippocampal GFAP+ cell density and increases vimentin and nestin expression.

  20. Extracellular metabolites in the cortex and hippocampus of epileptic patients.

    Science.gov (United States)

    Cavus, Idil; Kasoff, Willard S; Cassaday, Michael P; Jacob, Ralph; Gueorguieva, Ralitza; Sherwin, Robert S; Krystal, John H; Spencer, Dennis D; Abi-Saab, Walid M

    2005-02-01

    Interictal brain energy metabolism and glutamate-glutamine cycling are impaired in epilepsy and may contribute to seizure generation. We used the zero-flow microdialysis method to measure the extracellular levels of glutamate, glutamine, and the major energy substrates glucose and lactate in the epileptogenic and the nonepileptogenic cortex and hippocampus of 38 awake epileptic patients during the interictal period. Depth electrodes attached to microdialysis probes were used to identify the epileptogenic and the nonepileptogenic sites. The epileptogenic hippocampus had surprisingly high basal glutamate levels, low glutamine/glutamate ratio, high lactate levels, and indication for poor glucose utilization. The epileptogenic cortex had only marginally increased glutamate levels. We propose that interictal energetic deficiency in the epileptogenic hippocampus could contribute to impaired glutamate reuptake and glutamate-glutamine cycling, resulting in persistently increased extracellular glutamate, glial and neuronal toxicity, increased lactate production together with poor lactate and glucose utilization, and ultimately worsening energy metabolism. Our data suggest that a different neurometabolic process underlies the neocortical epilepsies.

  1. Characterization of NMDAR-independent learning in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Kaycie Kuss Tayler

    2011-05-01

    Full Text Available It is currently thought that memory formation requires the activation of NMDA receptors (NMDARs in the hippocampus. However, recent studies indicate that these receptors are not necessary for all forms of learning. The current experiments examine this issue using context fear conditioning in mice. First, we show that context fear can be acquired without NMDAR activation in previously trained animals. Mice trained in one environment (context A are subsequently able to learn about a second environment (context B in the presence of NMDAR antagonists. Second, we demonstrate that NMDAR-independent learning requires the hippocampus and is dependent on protein synthesis. However, unlike NMDAR-dependent learning, it is not contingent on the expression of activity-regulated cytoskeleton-associated protein (Arc. Lastly, we present data that suggests NMDAR-independent learning is only observed when recently stimulated neurons are re-activated during conditioning. These data suggest that context fear conditioning modifies synaptic plasticity mechanisms in the hippocampus and allows subsequent learning to occur in the absence of NMDAR activation.

  2. The role of the hippocampus in memory and mental construction.

    Science.gov (United States)

    Sheldon, Signy; Levine, Brian

    2016-04-01

    Much has been learned about the processes that support the remembrance of past autobiographical episodes and their importance for a number of cognitive tasks. This work has focused on hippocampal contributions to constructing coherent mental representations of scenarios for these tasks, which has opened up new questions about the underlying hippocampal mechanisms. We propose a new framework to answer these questions, which incorporates task demands that prompt hippocampal contributions to mental construction, the online formation of such mental representations, and how these demands relate to the functional organization of the hippocampus. Synthesizing findings from autobiographical memory research, our framework suggests that the interaction of two task characteristics influences the recruitment of the hippocampus: (1) the degree of task open-endedness (quantified by the presence/absence of a retrieval framework) and (2) the degree to which the integration of perceptual details is required. These characteristics inform the relative weighting of anterior and posterior hippocampal involvement, following an organizational model in which the anterior and posterior hippocampus support constructions on the basis of conceptual and perceptual representations, respectively. The anticipated outcome of our framework is a refined understanding of hippocampal contributions to memory and to the host of related cognitive functions. © 2016 New York Academy of Sciences.

  3. The Role of Hippocampus in the Pathophysiology of Depression

    Directory of Open Access Journals (Sweden)

    Özlem Donat Eker

    2009-06-01

    Full Text Available Hippocampus, as a part of the limbic cortex, has a variety of functions ranging from mating behavior to memory besides its role in the regulation of emotions. The hippocampus has reciprocal interactions of with other brain regions which act in the pathophysiology of major depressive disorder (MDD. Moreover, since the hippocampus is a scene for the neurogenesis, which can be seen as a response to antidepressant treatment, the hippocampus became a focus of attention in neuroimaging studies of MDD. It has been shown that brain derived neurotrophic factor (BDNF, that is responsible from the neurogenesis, is associated with the response to the antidepressants and antidepressant drugs are ineffective if neurogenesis is hindered.Hippocampal atrophy is expected with the decrease of neurogenesis as a result of the lower BDNF levels with the deleterious effects of glucocorticoids in depression. Recurrent and severe depression seems to cause such a volume reduction though first episode MDD subjects do not differ from healthy individuals in respect to their hippocampal volumes (HCVs measured by magnetic resonance imaging methods. One may argue regarding these findings that the atrophy in the hippocampus may be observed in the long term and the decrease in BDNF levels may predispose the volume reduction. Although it has been postulated that smaller HCV as a result of genetic and environmental factors and prior to the illness, may cause a vulnerability to MDD, sufficient evidence has not been accumulated yet and the view that HCV loss develops as depression progresses is widely accepted. Findings that serum BDNF (sBDNF is lower in MDD patients though HCVs of patients do not differ from healthy individuals and the positive correlation of sBDNF with HCV seen only in the patient group support this view. It can be assumed that depressed patients have sensitivity for the fluctuations in BDNF levels. Follow-up studies which consider effects of hipotalamo

  4. Effects of HZE irradiation on chemical neurotransmission in rodent hippocampus

    Science.gov (United States)

    Machida, Mayumi

    Space radiation represents a significant risk to the CNS (central nervous system) during space missions. Most harmful are the HZE (high mass, highly charged (Z), high energy) particles, e.g. 56Fe, which possess high ionizing ability, dense energy deposition pattern, and high penetrance. Accumulating evidence suggests that radiation has significant impact on cognitive functions. In ground-base experiments, HZE radiation induces pronounced deficits in hippocampus dependent learning and memory in rodents. However, the mechanisms underlying these impairments are mostly unknown. Exposure to HZE radiation elevates the level of oxidation, resulting in cell loss, tissue damage and functional deficits through direct ionization and generation of reactive oxygen species (ROS). When hippocampal slices were exposed to ROS, neuronal excitability was reduced. My preliminary results showed enhanced radio-vulnerability of the hippocampus and reduction in basal and depolarization-evoked [3H]-norepinephrine release after HZE exposure. These results raised the possibility that HZE radiation deteriorates cognitive function through radiation-induced impairments in hippocampal chemical neurotransmission, the hypothesis of this dissertation. In Aim 1 I have focused on the effects of HZE radiation on release of major neurotransmitter systems in the hippocampus. I have further extended my research on the levels of receptors of these systems in Aim 2. In Aim 3, I have studied the level of oxidation in membranes of my samples. My research reveals that HZE radiation significantly reduces hyperosmotic sucrose evoked [3H]-glutamate and [14C]-GABA release both three and six months post irradiation. The same radiation regimen also significantly enhances oxidative stress as indicated by increased levels of lipid peroxidation in the hippocampus, suggesting that increased levels of lipid peroxidation may play a role in reduction of neurotransmitter release. HZE radiation also significantly reduces

  5. Conscious experience and episodic memory: hippocampus at the crossroads.

    Science.gov (United States)

    Behrendt, Ralf-Peter

    2013-01-01

    If an instance of conscious experience of the seemingly objective world around us could be regarded as a newly formed event memory, much as an instance of mental imagery has the content of a retrieved event memory, and if, therefore, the stream of conscious experience could be seen as evidence for ongoing formation of event memories that are linked into episodic memory sequences, then unitary conscious experience could be defined as a symbolic representation of the pattern of hippocampal neuronal firing that encodes an event memory - a theoretical stance that may shed light into the mind-body and binding problems in consciousness research. Exceedingly detailed symbols that describe patterns of activity rapidly self-organizing, at each cycle of the θ rhythm, in the hippocampus are instances of unitary conscious experience that jointly constitute the stream of consciousness. Integrating object information (derived from the ventral visual stream and orbitofrontal cortex) with contextual emotional information (from the anterior insula) and spatial environmental information (from the dorsal visual stream), the hippocampus rapidly forms event codes that have the informational content of objects embedded in an emotional and spatiotemporally extending context. Event codes, formed in the CA3-dentate network for the purpose of their memorization, are not only contextualized but also allocentric representations, similarly to conscious experiences of events and objects situated in a seemingly objective and observer-independent framework of phenomenal space and time. Conscious perception, creating the spatially and temporally extending world that we perceive around us, is likely to be evolutionarily related to more fleeting and seemingly internal forms of conscious experience, such as autobiographical memory recall, mental imagery, including goal anticipation, and to other forms of externalized conscious experience, namely dreaming and hallucinations; and evidence pointing to

  6. Navigating the auditory scene: an expert role for the hippocampus.

    Science.gov (United States)

    Teki, Sundeep; Kumar, Sukhbinder; von Kriegstein, Katharina; Stewart, Lauren; Lyness, C Rebecca; Moore, Brian C J; Capleton, Brian; Griffiths, Timothy D

    2012-08-29

    Over a typical career piano tuners spend tens of thousands of hours exploring a specialized acoustic environment. Tuning requires accurate perception and adjustment of beats in two-note chords that serve as a navigational device to move between points in previously learned acoustic scenes. It is a two-stage process that depends on the following: first, selective listening to beats within frequency windows, and, second, the subsequent use of those beats to navigate through a complex soundscape. The neuroanatomical substrates underlying brain specialization for such fundamental organization of sound scenes are unknown. Here, we demonstrate that professional piano tuners are significantly better than controls matched for age and musical ability on a psychophysical task simulating active listening to beats within frequency windows that is based on amplitude modulation rate discrimination. Tuners show a categorical increase in gray matter volume in the right frontal operculum and right superior temporal lobe. Tuners also show a striking enhancement of gray matter volume in the anterior hippocampus, parahippocampal gyrus, and superior temporal gyrus, and an increase in white matter volume in the posterior hippocampus as a function of years of tuning experience. The relationship with gray matter volume is sensitive to years of tuning experience and starting age but not actual age or level of musicality. Our findings support a role for a core set of regions in the hippocampus and superior temporal cortex in skilled exploration of complex sound scenes in which precise sound "templates" are encoded and consolidated into memory over time in an experience-dependent manner.

  7. Conscious Experience and Episodic Memory: Hippocampus at the Crossroads

    Directory of Open Access Journals (Sweden)

    Ralf-Peter eBehrendt

    2013-05-01

    Full Text Available If an instance of conscious experience of the seemingly objective world around us could be regarded as a newly formed event memory, much as an instance of mental imagery has the content of a retrieved event memory, and if, therefore, the stream of conscious experience could be seen as evidence for ongoing formation of event memories that are linked into episodic memory sequences, then unitary conscious experience could be defined as a symbolic representation of the pattern of hippocampal neuronal firing that encodes an event memory – a theoretical stance that may shed light into the mind-body and binding problems in consciousness research. Exceedingly detailed symbols that describe patterns of activity rapidly self-organizing, at each cycle of the θ rhythm, in the hippocampus are instances of unitary conscious experience that jointly constitute the stream of consciousness. Integrating object information (derived from the ventral visual stream and orbitofrontal cortex with contextual emotional information (from the anterior insula and spatial environmental information (from the dorsal visual stream, the hippocampus rapidly forms event codes that have the informational content of objects embedded in an emotional and spatiotemporally extending context. Event codes, formed in the CA3-dentate network for the purpose of their memorization, are not only contextualized but also allocentric representations, similarly to conscious experiences of events and objects situated in a seemingly objective and observer-independent framework of phenomenal space and time. Conscious perception is likely to be related to more fleeting and seemingly internal forms of conscious experience, such as autobiographical memory recall, mental imagery, including goal anticipation, and to other forms of externalized conscious experience, namely dreaming and hallucinations; and evidence pointing to an important contribution of the hippocampus to these conscious phenomena will

  8. Altered Neurochemical Ingredient of Hippocampus in Patients with Bipolar Depression

    Directory of Open Access Journals (Sweden)

    Murad Atmaca

    2012-01-01

    Full Text Available Background. In a number of investigations, hippocampal neurochemicals were evaluated in the patients with bipolar disorder who were on their first episode or euthymic periods. However, we did not meet any investigation in which only patients with bipolar depression were examined. As a consequence, the objective of the present study was to examine both sides of hippocampus of patients with bipolar disorder in depressive episode and healthy controls using 1H-MRS. Methods. Thirteen patients with DSM-IV bipolar I disorder, most recent episode depressed, were recruited from the Department of Psychiatry at Firat University School of Medicine. We also studied 13 healthy comparison subjects who were without any DSM-IV Axis I disorders recruited from the hospital staff. The patients and controls underwent proton magnetic resonance spectroscopy (1H-MRS of their hippocampus. NAA, CHO, and CRE values were measured. Results. No significant effect of diagnosis was observed for NAA/CRE ratio. For the NAA/CHO ratio, the ANCOVA with age, gender, and whole brain volume as covariates revealed that the patients with bipolar depression had significantly lower ratio compared to healthy control subjects for right and for left side. As for the CHO/CRE ratio, the difference was statistically significant for right side, with an effect diagnosis of F = 4.763, P = 0.038, and was very nearly significant for left side, with an effect diagnosis of F = 3.732, P = 0.064. Conclusions. We found that the patients with bipolar depression had lower NAA/CHO and higher CHO/CRE ratios compared to those of healthy control subjects. The findings of the present study also suggest that there may be a degenerative process concerning the hippocampus morphology in the patients with bipolar depression.

  9. Hippocampus sparing in whole-brain radiotherapy. A review

    Energy Technology Data Exchange (ETDEWEB)

    Oskan, F. [University of Munich, Department of Radiation Oncology and CCC Neuro-Oncology, Munich (Germany); Saarland University Medical Center, Department of Radiation Oncology, Homburg/Saar (Germany); Ganswindt, U.; Schwarz, S.B.; Manapov, F.; Belka, C.; Niyazi, M. [University of Munich, Department of Radiation Oncology and CCC Neuro-Oncology, Munich (Germany)

    2014-04-15

    Radiation treatment techniques for whole-brain radiation therapy (WBRT) have not changed significantly since development of the procedure. However, the recent development of novel techniques such as intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT) and helical tomotherapy, as well as an increasing body of evidence concerning neural stem cells (NSCs) have altered the conventional WBRT treatment paradigm. In this regard, hippocampus-sparing WBRT is a novel technique that aims to spare critical hippocampus regions without compromising tumour control. Published data on this new technique are limited to planning and feasibility studies; data on patient outcome are still lacking. However, several prospective trials to analyse the feasibility of this technique and to document clinical outcome in terms of reduced neurotoxicity are ongoing. (orig.) [German] Die Technik der Ganzhirnbestrahlung (''whole-brain radiation therapy'', WBRT) hat sich seit der Entwicklung nicht wesentlich veraendert. Allerdings stellten die Neuentwicklung von Techniken wie die intensitaetsmodulierte Strahlentherapie (IMRT), die volumenmodulierte Arc-Therapie (VMAT) oder die helikale Tomotherapie sowie immer groesseres Wissen ueber das neurale Stammzellkompartiment (NSCs) das herkoemmliche Ganzhirn-Paradigma in Frage. Die hippocampusschonende Ganzhirnbestrahlung ist eine neuartige Technik, welche die kritische Region des Hippocampus schont, ohne die Tumorkontrolle zu gefaehrden. Ueber diese Technik gibt es bisher nur eine begrenzte Datenlage im Sinne von Planungs- und Machbarkeitsstudien. Klinische Daten bzgl. der Behandlungsergebnisse fehlen nach wie vor, aber einige prospektive Studien sind im Gange, um nicht nur die Machbarkeit zu belegen, sondern auch das klinische Outcome im Sinne einer verringerten Neurotoxizitaet nachzuweisen. (orig.)

  10. Intracranial EEG correlates of implicit relational inference within the hippocampus.

    Science.gov (United States)

    Reber, T P; Do Lam, A T A; Axmacher, N; Elger, C E; Helmstaedter, C; Henke, K; Fell, J

    2016-01-01

    Drawing inferences from past experiences enables adaptive behavior in future situations. Inference has been shown to depend on hippocampal processes. Usually, inference is considered a deliberate and effortful mental act which happens during retrieval, and requires the focus of our awareness. Recent fMRI studies hint at the possibility that some forms of hippocampus-dependent inference can also occur during encoding and possibly also outside of awareness. Here, we sought to further explore the feasibility of hippocampal implicit inference, and specifically address the temporal evolution of implicit inference using intracranial EEG. Presurgical epilepsy patients with hippocampal depth electrodes viewed a sequence of word pairs, and judged the semantic fit between two words in each pair. Some of the word pairs entailed a common word (e.g., "winter-red," "red-cat") such that an indirect relation was established in following word pairs (e.g., "winter-cat"). The behavioral results suggested that drawing inference implicitly from past experience is feasible because indirect relations seemed to foster "fit" judgments while the absence of indirect relations fostered "do not fit" judgments, even though the participants were unaware of the indirect relations. A event-related potential (ERP) difference emerging 400 ms post-stimulus was evident in the hippocampus during encoding, suggesting that indirect relations were already established automatically during encoding of the overlapping word pairs. Further ERP differences emerged later post-stimulus (1,500 ms), were modulated by the participants' responses and were evident during encoding and test. Furthermore, response-locked ERP effects were evident at test. These ERP effects could hence be a correlate of the interaction of implicit memory with decision-making. Together, the data map out a time-course in which the hippocampus automatically integrates memories from discrete but related episodes to implicitly influence future

  11. The hippocampus and exploration: dynamically evolving behavior and neural representations

    Directory of Open Access Journals (Sweden)

    Adam eJohnson

    2012-07-01

    Full Text Available We develop a normative statistical approach to exploratory behavior called information foraging. Information foraging highlights the specific processes that contribute to active, rather than passive, exploration and learning. We hypothesize that the hippocampus plays a critical role in active exploration through directed information foraging by supporting a set of processes that allow an individual to determine where to sample. By examining these processes, we show how information directed information foraging provides a formal theoretical explanation for the common hippocampal substrates of constructive memory, vicarious trial and error behavior, schema-based facilitation of memory performance, and memory consolidation.

  12. The hippocampus and exploration: dynamically evolving behavior and neural representations

    Science.gov (United States)

    Johnson, Adam; Varberg, Zachary; Benhardus, James; Maahs, Anthony; Schrater, Paul

    2012-01-01

    We develop a normative statistical approach to exploratory behavior called information foraging. Information foraging highlights the specific processes that contribute to active, rather than passive, exploration and learning. We hypothesize that the hippocampus plays a critical role in active exploration through directed information foraging by supporting a set of processes that allow an individual to determine where to sample. By examining these processes, we show how information directed information foraging provides a formal theoretical explanation for the common hippocampal substrates of constructive memory, vicarious trial and error behavior, schema-based facilitation of memory performance, and memory consolidation. PMID:22848196

  13. Muscarinic receptor compensation in hippocampus of alzheimer patients. [Autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Nordberg, A; Larsson, C; Adolfsson, R; Alafuzoff, I; Winblad, B [Uppsala Univ. (Sweden)

    1983-01-01

    The activity of the acetylcholine synthesizing enzyme choline acetyltransferase (ChAT) (presynaptic marker) and number of muscarine-like receptor binding sites have been measured in the hippocampus from eight individuals with senile dementia of Alzheimer type (SDAT) and ten controls. A negative correlation (r=0.80; p<0.05) was found between the ChAT activity and the number of muscarine-like receptors in the SDAT group but not in the controls. The findings might indicate an ongoing compensatory receptor mechanism as a response to changes in presynaptic cholinergic activity.

  14. High glycogen levels in the hippocampus of patients with epilepsy

    DEFF Research Database (Denmark)

    Dalsgaard, Mads K; Madsen, Flemming F; Secher, Niels H

    2006-01-01

    During intense cerebral activation approximately half of the glucose plus lactate taken up by the human brain is not oxidized and could replenish glycogen deposits, but the human brain glycogen concentration is unknown. In patients with temporal lobe epilepsy, undergoing curative surgery, brain......, glycogen was similarly higher than in grey and white matter. Consequently, in human grey and white matter and, particularly, in the hippocampus of patients with temporal lope epilepsy, glycogen constitutes a large, active energy reserve, which may be of importance for energy provision during sustained...

  15. Cellular targets of nitric oxide in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Katalin Bartus

    Full Text Available In the hippocampus, as in many other CNS areas, nitric oxide (NO participates in synaptic plasticity, manifested as changes in pre- and/or postsynaptic function. While it is known that these changes are brought about by cGMP following activation of guanylyl cyclase-coupled NO receptors attempts to locate cGMP by immunocytochemistry in hippocampal slices in response to NO have failed to detect the cGMP elevation where expected, i.e. in the pyramidal neurones. Instead, astrocytes, unidentified varicose fibres and GABA-ergic nerve terminals are reported to be the prominent NO targets, raising the possibility that NO acts indirectly via other cells. We have re-investigated the distribution of cGMP generated in response to endogenous and exogenous NO in hippocampal slices using immunohistochemistry and new conditions designed to optimise cGMP accumulation and, hence, its detectability. The conditions included use of tissue from the developing rat hippocampus, a potent inhibitor of phosphodiesterase-2, and an allosteric enhancer of the NO-receptive guanylyl cyclase. Under these conditions, cGMP was formed in response to endogenous NO and was found in a population of pyramidal cell somata in area CA3 and subiculum as well as in structures described previously. The additional presence of exogenous NO resulted in hippocampal cGMP reaching the highest level recorded for brain tissue (1700 pmol/mg protein and in cGMP immunolabelling throughout the pyramidal cell layer. Populations of axons and interneurones were also stained. According with these results, immunohistochemistry for the common NO receptor β1-subunit indicated widespread expression. A similar staining pattern for the α1-subunit with an antibody used previously in the hippocampus and elsewhere, however, proved to be artefactual. The results indicate that the targets of NO in the hippocampus are more varied and extensive than previous evidence had suggested and, in particular, that the

  16. Neural activity in the hippocampus during conflict resolution.

    Science.gov (United States)

    Sakimoto, Yuya; Okada, Kana; Hattori, Minoru; Takeda, Kozue; Sakata, Shogo

    2013-01-15

    This study examined configural association theory and conflict resolution models in relation to hippocampal neural activity during positive patterning tasks. According to configural association theory, the hippocampus is important for responses to compound stimuli in positive patterning tasks. In contrast, according to the conflict resolution model, the hippocampus is important for responses to single stimuli in positive patterning tasks. We hypothesized that if configural association theory is applicable, and not the conflict resolution model, the hippocampal theta power should be increased when compound stimuli are presented. If, on the other hand, the conflict resolution model is applicable, but not configural association theory, then the hippocampal theta power should be increased when single stimuli are presented. If both models are valid and applicable in the positive patterning task, we predict that the hippocampal theta power should be increased by presentation of both compound and single stimuli during the positive patterning task. To examine our hypotheses, we measured hippocampal theta power in rats during a positive patterning task. The results showed that hippocampal theta power increased during the presentation of a single stimulus, but did not increase during the presentation of a compound stimulus. This finding suggests that the conflict resolution model is more applicable than the configural association theory for describing neural activity during positive patterning tasks. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. High Plasticity of New Granule Cells in the Aging Hippocampus

    Directory of Open Access Journals (Sweden)

    Mariela F. Trinchero

    2017-10-01

    Full Text Available Summary: During aging, the brain undergoes changes that impair cognitive capacity and circuit plasticity, including a marked decrease in production of adult-born hippocampal neurons. It is unclear whether development and integration of those new neurons are also affected by age. Here, we show that adult-born granule cells (GCs in aging mice are scarce and exhibit slow development, but they display a remarkable potential for structural plasticity. Retrovirally labeled 3-week-old GCs in middle-aged mice were small, underdeveloped, and disconnected. Neuronal development and integration were accelerated by voluntary exercise or environmental enrichment. Similar effects were observed via knockdown of Lrig1, an endogenous negative modulator of neurotrophin receptors. Consistently, blocking neurotrophin signaling by Lrig1 overexpression abolished the positive effects of exercise. These results demonstrate an unparalleled degree of plasticity in the aging brain mediated by neurotrophins, whereby new GCs remain immature until becoming rapidly recruited to the network by activity. : Trinchero et al. show that development of new granule cells born in the adult hippocampus is strongly influenced by age. In the aging hippocampus, new neurons remain immature for prolonged intervals, yet voluntary exercise triggers their rapid growth and functional synaptogenesis. This extensive structural remodeling is mediated by neurotrophins. Keywords: adult neurogenesis, dentate gyrus, functional integration, neurotrophins, synaptogenesis, exercise

  18. THEORETICAL REVIEW The Hippocampus, Time, and Memory Across Scales

    Science.gov (United States)

    Howard, Marc W.; Eichenbaum, Howard

    2014-01-01

    A wealth of experimental studies with animals have offered insights about how neural networks within the hippocampus support the temporal organization of memories. These studies have revealed the existence of “time cells” that encode moments in time, much as the well-known “place cells” map locations in space. Another line of work inspired by human behavioral studies suggests that episodic memories are mediated by a state of temporal context that changes gradually over long time scales, up to at least a few thousand seconds. In this view, the “mental time travel” hypothesized to support the experience of episodic memory corresponds to a “jump back in time” in which a previous state of temporal context is recovered. We suggest that these 2 sets of findings could be different facets of a representation of temporal history that maintains a record at the last few thousand seconds of experience. The ability to represent long time scales comes at the cost of discarding precise information about when a stimulus was experienced—this uncertainty becomes greater for events further in the past. We review recent computational work that describes a mechanism that could construct such a scale-invariant representation. Taken as a whole, this suggests the hippocampus plays its role in multiple aspects of cognition by representing events embedded in a general spatiotemporal context. The representation of internal time can be useful across nonhippocampal memory systems. PMID:23915126

  19. The human hippocampus: cognitive maps or relational memory?

    Science.gov (United States)

    Kumaran, Dharshan; Maguire, Eleanor A

    2005-08-03

    The hippocampus is widely accepted to play a pivotal role in memory. Two influential theories offer competing accounts of its fundamental operating mechanism. The cognitive map theory posits a special role in mapping large-scale space, whereas the relational theory argues it supports amodal relational processing. Here, we pit the two theories against each other using a novel paradigm in which the relational processing involved in navigating in a city was matched with similar navigational and relational processing demands in a nonspatial (social) domain. During functional magnetic resonance imaging, participants determined the optimal route either between friends' homes or between the friends themselves using social connections. Separate brain networks were engaged preferentially during the two tasks, with hippocampal activation driven only by spatial relational processing. We conclude that the human hippocampus appears to have a bias toward the processing of spatial relationships, in accordance with the cognitive map theory. Our results both advance our understanding of the nature of the hippocampal contribution to memory and provide insights into how social networks are instantiated at the neural level.

  20. Alzheimer's disease and magnetic resonance spectroscopy of the hippocampus

    International Nuclear Information System (INIS)

    Engelhardt, Eliasz; Moreira, Denise M.; Laks, Jerson; Marinho, Valeska M.; Rozenthal, Marcia; Oliveira Junior, Amarino C.

    2001-01-01

    Objective: acquisition of data of magnetic resonance metabolite spectrum of the hippocampal formation (hippocampus-hc) in the elderly, normal and with Alzheimer's disease (AD). Method: Subjects matched for age: a. normal sample (n=20), CDR=0, and b. AD sample (n=40), CDR 1 and 2. Technique: Signa Horizon LX-GE, 1.5T, 1 H-MRS with automated software PROBE/SV, VOI: hc (right and left); single voxel (2x2x2cm); TR 1500ms/TE 50ms; PRESS; metabolites: N-acetylaspartate (Naa), choline (Cho), creatine (Cr), myo-inositol (mI). Results: The present data relate to the ratios of Naa, Cho and mI, with Cr taken as reference, and the mI/Naa ratio. The study showed reduction of Naa, increase of mI and of the mI/Naa ratio, and not consistent results for Cho. The results of the whole sample of AD patients compared to the pooled normal mean ± sd were significant for Naa, mI and mI/Naa (p<0.01). Accuracy in relation to the individual values of both samples showed satisfactory levels of sensitivity, specificity and positive predictive value. Conclusion: The present results can be used as a helpful tool to detect pathologic changes of the hippocampus in AD, and allowing greater accuracy and an earlier diagnosis of this disease. (author)

  1. The hippocampus facilitates integration within a symbolic field.

    Science.gov (United States)

    Cornelius, John Thor

    2017-10-01

    This paper attempts to elaborate a fundamental brain mechanism involved in the creation and maintenance of symbolic fields of thought. It will integrate theories of psychic spaces as explored by Donald Winnicott and Wilfred Bion with the neuroscientific examinations of those with bilateral hippocampal injury to show how evidence from both disciplines sheds important light on this aspect of mind. Possibly originating as a way of maintaining an oriented, first person psychic map, this capacity allows individuals a dynamic narrative access to a realm of layered elements and their connections. If the proposed hypothesis is correct, the hippocampus facilitates the integration of this symbolic field of mind, where narrative forms of thinking, creativity, memory, and dreaming are intertwined. Without the hippocampus, there is an inability to engage many typical forms of thought itself. Also, noting the ways these individuals are not impaired supports theories about other faculties of mind, providing insight into their possible roles within human thought. The evidence of different systems working in conjunction with the symbolic field provides tantalizing clues about these fundamental mechanisms of brain and mind that are normally seamlessly integrated, and hints at future areas of clinical and laboratory research, both within neuroscience and psychoanalysis. © 2017 The Authors. The International Journal of Psychoanalysis published by John Wiley & Sons Ltd on behalf of Institute of Psychoanalysis.

  2. Reliable activation of immature neurons in the adult hippocampus.

    Directory of Open Access Journals (Sweden)

    Lucas A Mongiat

    Full Text Available Neurons born in the adult dentate gyrus develop, mature, and connect over a long interval that can last from six to eight weeks. It has been proposed that, during this period, developing neurons play a relevant role in hippocampal signal processing owing to their distinctive electrical properties. However, it has remained unknown whether immature neurons can be recruited into a network before synaptic and functional maturity have been achieved. To address this question, we used retroviral expression of green fluorescent protein to identify developing granule cells of the adult mouse hippocampus and investigate the balance of afferent excitation, intrinsic excitability, and firing behavior by patch clamp recordings in acute slices. We found that glutamatergic inputs onto young neurons are significantly weaker than those of mature cells, yet stimulation of cortical excitatory axons elicits a similar spiking probability in neurons at either developmental stage. Young neurons are highly efficient in transducing ionic currents into membrane depolarization due to their high input resistance, which decreases substantially in mature neurons as the inward rectifier potassium (Kir conductance increases. Pharmacological blockade of Kir channels in mature neurons mimics the high excitability characteristic of young neurons. Conversely, Kir overexpression induces mature-like firing properties in young neurons. Therefore, the differences in excitatory drive of young and mature neurons are compensated by changes in membrane excitability that render an equalized firing activity. These observations demonstrate that the adult hippocampus continuously generates a population of highly excitable young neurons capable of information processing.

  3. Electrolytic Lesions of the Dorsal Hippocampus Disrupt Renewal of Conditional Fear after Extinction

    Science.gov (United States)

    Ji, Jinzhao; Maren, Stephen

    2005-01-01

    There is a growing body of evidence that the hippocampus is critical for context-dependent memory retrieval. In the present study, we used Pavlovian fear conditioning in rats to examine the role of the dorsal hippocampus (DH) in the context-specific expression of fear memory after extinction (i.e., renewal). Pre-training electrolytic lesions of…

  4. Contributions of Volumetrics of the Hippocampus and Thalamus to Verbal Memory in Temporal Lobe Epilepsy Patients

    Science.gov (United States)

    Stewart, Christopher C.; Griffith, H. Randall; Okonkwo, Ozioma C.; Martin, Roy C.; Knowlton, Robert K.; Richardson, Elizabeth J.; Hermann, Bruce P.; Seidenberg, Michael

    2009-01-01

    Recent theories have posited that the hippocampus and thalamus serve distinct, yet related, roles in episodic memory. Whereas the hippocampus has been implicated in long-term memory encoding and storage, the thalamus, as a whole, has been implicated in the selection of items for subsequent encoding and the use of retrieval strategies. However,…

  5. Design-based estimation of neuronal number and individual neuronal volume in the rat hippocampus

    DEFF Research Database (Denmark)

    Hosseini-Sharifabad, Mohammad; Nyengaard, Jens Randel

    2007-01-01

    Tools recently developed in stereology were employed for unbiased estimation of the neuronal number and volume in three major subdivisions of rat hippocampus (dentate granular, CA1 and CA3 pyramidal layers). The optical fractionator is used extensively in quantitative studies of the hippocampus; ...

  6. Post-Training Reversible Inactivation of the Hippocampus Enhances Novel Object Recognition Memory

    Science.gov (United States)

    Oliveira, Ana M. M.; Hawk, Joshua D.; Abel, Ted; Havekes, Robbert

    2010-01-01

    Research on the role of the hippocampus in object recognition memory has produced conflicting results. Previous studies have used permanent hippocampal lesions to assess the requirement for the hippocampus in the object recognition task. However, permanent hippocampal lesions may impact performance through effects on processes besides memory…

  7. Reactivations of emotional memory in the hippocampus-amygdala system during sleep.

    Science.gov (United States)

    Girardeau, Gabrielle; Inema, Ingrid; Buzsáki, György

    2017-11-01

    The consolidation of context-dependent emotional memory requires communication between the hippocampus and the basolateral amygdala (BLA), but the mechanisms of this process are unknown. We recorded neuronal ensembles in the hippocampus and BLA while rats learned the location of an aversive air puff on a linear track, as well as during sleep before and after training. We found coordinated reactivations between the hippocampus and the BLA during non-REM sleep following training. These reactivations peaked during hippocampal sharp wave-ripples (SPW-Rs) and involved a subgroup of BLA cells positively modulated during hippocampal SPW-Rs. Notably, reactivation was stronger for the hippocampus-BLA correlation patterns representing the run direction that involved the air puff than for the 'safe' direction. These findings suggest that consolidation of contextual emotional memory occurs during ripple-reactivation of hippocampus-amygdala circuits.

  8. Medial Entorhinal Cortex Lesions Only Partially Disrupt Hippocampal Place Cells and Hippocampus-Dependent Place Memory

    Directory of Open Access Journals (Sweden)

    Jena B. Hales

    2014-11-01

    Full Text Available The entorhinal cortex provides the primary cortical projections to the hippocampus, a brain structure critical for memory. However, it remains unclear how the precise firing patterns of medial entorhinal cortex (MEC cells influence hippocampal physiology and hippocampus-dependent behavior. We found that complete bilateral lesions of the MEC resulted in a lower proportion of active hippocampal cells. The remaining active cells had place fields, but with decreased spatial precision and decreased long-term spatial stability. In addition, MEC rats were as impaired in the water maze as hippocampus rats, while rats with combined MEC and hippocampal lesions had an even greater deficit. However, MEC rats were not impaired on other hippocampus-dependent tasks, including those in which an object location or context was remembered. Thus, the MEC is not necessary for all types of spatial coding or for all types of hippocampus-dependent memory, but it is necessary for the normal acquisition of place memory.

  9. Adult Onset-hypothyroidism has Minimal Effects on Synaptic Transmission in the Hippocampus of Rats Independent of Hypothermia

    Science.gov (United States)

    Introduction: Thyroid hormones (TH) influence central nervous system (CNS) function during development and in adulthood. The hippocampus, a brain area critical for learning and memory is sensitive to TH insufficiency. Synaptic transmission in the hippocampus is impaired following...

  10. Identification and characterization of PPARα ligands in the hippocampus.

    Science.gov (United States)

    Roy, Avik; Kundu, Madhuchhanda; Jana, Malabendu; Mishra, Rama K; Yung, Yeni; Luan, Chi-Hao; Gonzalez, Frank J; Pahan, Kalipada

    2016-12-01

    Peroxisome proliferator-activated receptor-α (PPARα) regulates hepatic fatty acid catabolism and mediates the metabolic response to starvation. Recently we found that PPARα is constitutively activated in nuclei of hippocampal neurons and controls plasticity via direct transcriptional activation of CREB. Here we report the discovery of three endogenous PPARα ligands-3-hydroxy-(2,2)-dimethyl butyrate, hexadecanamide, and 9-octadecenamide-in mouse brain hippocampus. Mass spectrometric detection of these compounds in mouse hippocampal nuclear extracts, in silico interaction studies, time-resolved FRET analyses, and thermal shift assay results clearly indicated that these three compounds served as ligands of PPARα. Site-directed mutagenesis studies further revealed that PPARα Y464 and Y314 are involved in binding these hippocampal ligands. Moreover, these ligands activated PPARα and upregulated the synaptic function of hippocampal neurons. These results highlight the discovery of hippocampal ligands of PPARα capable of modulating synaptic functions.

  11. Frequency-dependent glycinergic inhibition modulates plasticity in hippocampus.

    Science.gov (United States)

    Keck, Tara; Lillis, Kyle P; Zhou, Yu-Dong; White, John A

    2008-07-16

    Previous studies have demonstrated the presence of functional glycine receptors (GlyRs) in hippocampus. In this work, we examine the baseline activity and activity-dependent modulation of GlyRs in region CA1. We find that strychnine-sensitive GlyRs are open in the resting CA1 pyramidal cell, creating a state of tonic inhibition that "shunts" the magnitude of EPSPs evoked by electrical stimulation of the Schaffer collateral inputs. This GlyR-mediated shunting conductance is independent of the presynaptic stimulation rate; however, pairs of presynaptic and postsynaptic action potentials, repeated at frequencies above 5 Hz, reduce the GlyR-mediated conductance and increase peak EPSP magnitudes to levels at least 20% larger than those seen with presynaptic stimulation alone. We refer to this phenomenon as rate-dependent efficacy (RDE). Exogenous GlyR agonists (glycine, taurine) block RDE by preventing the closure of postsynaptic GlyRs. The GlyR antagonist strychnine blocks postsynaptic GlyRs under all conditions, occluding RDE. During RDE, GlyRs are less responsive to local glycine application, suggesting that a reduction in the number or sensitivity of membrane-inserted GlyRs underlies RDE. By extending the RDE induction protocol to include 500 paired presynaptic and postsynaptic spikes, we can induce long-term synaptic depression (LTD). Manipulations that lead to reduced functionality of GlyRs, either pharmacologically or through RDE, also lead to increased LTD. This result suggests that RDE contributes to long-term synaptic plasticity in the hippocampus.

  12. Propagation of cortical spreading depression into the hippocampus: The role of the entorhinal cortex.

    Science.gov (United States)

    Martens-Mantai, Tanja; Speckmann, Erwin-Josef; Gorji, Ali

    2014-07-22

    Propagation of cortical spreading depression (CSD) to the subcortical structures could be the underlying mechanism of some neurological deficits in migraine with aura. The entorhinal cortex (EC) as a gray matter bridge between the neocortex and subcortical regions plays an important role in this propagation. In vitro combined neocortex-hippocampus brain slices were used to study the propagation pattern of CSD between the neocortex and the hippocampus. The effects of different compounds as well as tetanic electrical stimulations in the EC on propagation of CSD to the hippocampus were investigated. Repetitive induction of CSD by KCl injection in the somatosensory cortex enhanced the probability of CSD entrance to the hippocampus via EC. Local application of AMPA receptor blocker CNQX and cannabinoid receptor agonist WIN 55212-2 in EC facilitated the propagation of CSD to the hippocampus, whereas application of NMDA receptor blocker APV and GABA A receptor blocker bicuculline in this region reduced the probability of CSD penetration to the hippocampus. Application of tetanic stimulation in EC also facilitated the propagation of CSD entrance to the hippocampus. Our data suggest the importance of synaptic plasticity of EC in filtering the propagation of CSD into subcortical structures and possibly the occurrence of concomitant neurological deficits. Synapse, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

  13. Effect of intrahippocampal kainic acid injections and surgical lesions on neurotransmitters in hippocampus and septum

    Energy Technology Data Exchange (ETDEWEB)

    Fonnum, F; Walaas, I

    1978-01-01

    Local injection of kainic acid (2 ..mu..g) was accompanied by destruction of intrinsic neurons in the dorsal part of hippocampus. The lesion was accompanied by a 75% reduction in glutamate decarboxylase activity, a 60% reduction in the high affinity uptake of L-glutamate, a 40 to 60% reduction in the endogeneous levels of aspartate, glutamate and GABA and no changes in the activities of choline acetyltransferase or aromatic amino acid decarboxylase in the dorsal hippocampus. Unilateral destruction of neurons in the dorsal hippocampus was followed by a 20 to 40% reduction in the high affinity uptake of glutamate in lateral, but not in medial septum, on both sides. There was no reduction in choline acetyltransferase, glutamate decarboxylase or aromatic amino acid decarboxylase activities in the lateral or medial part of the septum. Transection of fimbria and superior fornix was accompanied by a severe reduction in choline acetyltransferase and aromatic amino acid decarboxylase activity in hippocampus, in the high affinity uptake of glutamate and in the endogenous level of glutamate in the lateral septum. The results are consistent with the concept that in the hippocampus kainic acid destroys intrinsic neurons and not afferent fibres. It seems therefore that all GABAergic fibres in the hippocampus belong to intrinsic neurons whereas glutamergic and aspartergic neurons belong partly to local neurons. The connection from the hippocampus to the lateral septum probably uses glutamate as a transmitter.

  14. Diffusion-weighted imaging in transient global amnesia exposes the CA1 region of the hippocampus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Yun; Kim, Jae Hyoung; Weon, Young-Cheol; Youn, Sung Won; Kim, Sung Hyun [Seoul National University Bundang Hospital, Department of Radiology, Seoul National University College of Medicine, Seongnam-si (Korea); Lee, Jung Seok; Kim, Sang Yun [Seoul National University Bundang Hospital, Department of Neurology, Seoul National University College of Medicine, Seongnam-si (Korea)

    2007-06-15

    Transient global amnesia (TGA) is characterized by a sudden onset of anterograde amnesia without alteration of consciousness or personal identity. Interestingly, recent studies have reported a high frequency of small high-signal abnormalities in the hippocampus with diffusion-weighted (DW) imaging, and ischemia has been proposed as an etiology of TGA. We hypothesized that TGA lesions occur preferentially in the CA1 region of the hippocampus, known to be susceptible to ischemia. Over a 30-month period 34 patients with TGA underwent MRI including DW imaging within 4 days of symptom onset. Patients with high-signal abnormalities in the hippocampus on the initial DW images underwent subsequent DW and T2-weighted imaging in the coronal plane to identify the precise lesion locations. Fourteen patients had small (1-3 mm) high-signal abnormalities in the hippocampus unilaterally on DW images. One of these patients had two lesions in one hippocampus and therefore in total 15 lesions were identified: four in the hippocampal head, and 11 in the body. Eleven lesions in ten patients with available coronal images were clearly demonstrated on both coronal DW and T2-weighted images and were localized to the lateral portion of the hippocampus, corresponding to the CA1 region. Lesions associated with TGA were localized exclusively to the lateral portion of the hippocampus corresponding to the CA1 region. This finding supports the ischemic etiology of TGA; however, the pathophysiological mechanism involved requires further study. (orig.)

  15. Diffusion-weighted imaging in transient global amnesia exposes the CA1 region of the hippocampus

    International Nuclear Information System (INIS)

    Lee, Ho Yun; Kim, Jae Hyoung; Weon, Young-Cheol; Youn, Sung Won; Kim, Sung Hyun; Lee, Jung Seok; Kim, Sang Yun

    2007-01-01

    Transient global amnesia (TGA) is characterized by a sudden onset of anterograde amnesia without alteration of consciousness or personal identity. Interestingly, recent studies have reported a high frequency of small high-signal abnormalities in the hippocampus with diffusion-weighted (DW) imaging, and ischemia has been proposed as an etiology of TGA. We hypothesized that TGA lesions occur preferentially in the CA1 region of the hippocampus, known to be susceptible to ischemia. Over a 30-month period 34 patients with TGA underwent MRI including DW imaging within 4 days of symptom onset. Patients with high-signal abnormalities in the hippocampus on the initial DW images underwent subsequent DW and T2-weighted imaging in the coronal plane to identify the precise lesion locations. Fourteen patients had small (1-3 mm) high-signal abnormalities in the hippocampus unilaterally on DW images. One of these patients had two lesions in one hippocampus and therefore in total 15 lesions were identified: four in the hippocampal head, and 11 in the body. Eleven lesions in ten patients with available coronal images were clearly demonstrated on both coronal DW and T2-weighted images and were localized to the lateral portion of the hippocampus, corresponding to the CA1 region. Lesions associated with TGA were localized exclusively to the lateral portion of the hippocampus corresponding to the CA1 region. This finding supports the ischemic etiology of TGA; however, the pathophysiological mechanism involved requires further study. (orig.)

  16. Competitive Trace Theory: A Role for the Hippocampus in Contextual Interference during Retrieval.

    Science.gov (United States)

    Yassa, Michael A; Reagh, Zachariah M

    2013-01-01

    Much controversy exists regarding the role of the hippocampus in retrieval. The two dominant and competing accounts have been the Standard Model of Systems Consolidation (SMSC) and Multiple Trace Theory (MTT), which specifically make opposing predictions as to the necessity of the hippocampus for retrieval of remote memories. Under SMSC, memories eventually become independent of the hippocampus as they become more reliant on cortical connectivity, and thus the hippocampus is not required for retrieval of remote memories, only recent ones. MTT on the other hand claims that the hippocampus is always required no matter the age of the memory. We argue that this dissociation may be too simplistic, and a continuum model may be better suited to address the role of the hippocampus in retrieval of remote memories. Such a model is presented here with the main function of the hippocampus during retrieval being "recontextualization," or the reconstruction of memory using overlapping traces. As memories get older, they are decontextualized due to competition among partially overlapping traces and become more semantic and reliant on neocortical storage. In this framework dubbed the Competitive Trace Theory (CTT), consolidation events that lead to the strengthening of memories enhance conceptual knowledge (semantic memory) at the expense of contextual details (episodic memory). As a result, remote memories are more likely to have a stronger semantic representation. At the same time, remote memories are also more likely to include illusory details. The CTT is a novel candidate model that may provide some resolution to the memory consolidation debate.

  17. Fast and robust extraction of hippocampus from MR images for diagnostics of Alzheimer's disease

    DEFF Research Database (Denmark)

    Lötjönen, Jyrki; Wolz, Robin; Koikkalainen, Juha

    2011-01-01

    importance in the clinical decision making. We propose a method for computing automatically the volume of hippocampus using a modified multi-atlas segmentation framework, including an improved initialization of the framework and the correction of partial volume effect. The method produced a high similarity......Assessment of temporal lobe atrophy from magnetic resonance images is a part of clinical guidelines for the diagnosis of prodromal Alzheimer's disease. As hippocampus is known to be among the first areas affected by the disease, fast and robust definition of hippocampus volume would be of great...

  18. Neurogenic effects of fingolimod in hippocampus, affecting fear memory.

    Directory of Open Access Journals (Sweden)

    Paschalis Efstathopoulos

    2014-05-01

    Full Text Available Fingolimod (FTY720; Gilenya™,Novartis Pharma AG is a recently developed Sphingosine-1-Phosphate (S1P analogue, orally administered as a new therapeutic agent in Multiple Sclerosis (MS (Brinkmann V. et al. 2010. S1P receptors (S1PRs are expressed in various sites in the CNS including the subventricular zone (Waeber C. et al. 1999; Choi J.W. et al. 2013 while endogenous S1P was shown to induce proliferation and morphological changes in embryonic hippocampal neural progenitors in culture (Harada J. et al. 2004. In this study we investigated the effects of fingolimod on adult rodent hippocampal neurogenesis and their possible functional role. To this aim, thymidine analogue BrdU was injected at the end or before a 2-week i.p. administration of a therapeutic dose of Fingolimod (0,3 mg/kg in young and old mice. Stereological counts of BrdU+ cells revealed significant increase in both proliferation, and survival of neural stem cells (NSC in the area of Dentate Gyrus (DG of the hippocampus, compared to control untreated animals of young but not old ages. In the case of survival assessment, most of the BrdU + cells were also positive for NeuN, suggesting an increase of newly formed neurons. The increase in proliferation rate of NSC was also confirmed by BrdU uptake in hippocampal NSC cultures in vitro, implying that the effects of fingolimod are cell autonomous. Immunohistochemical analysis showed that S1PR was not co-localized with GFAP+ cells in the Subgranular zone (SGZ of the DG, but was strongly co-localized with transcription factor MASH1 and weakly with DcX or PSA-NCAM positive neural progenitors. These findings suggest that expression of S1PR1 in the SGZ is restricted to transit amplifying neural progenitors and maintained also in the stage of neuroblast. In addition, the effects of Fingolimod in DG neurogenesis were positively correlated to enhanced fear memory and increased context discrimination, an established DG-dependent cognitive task

  19. Endogenous opioid peptides as neurotransmitters in the rat hippocampus

    International Nuclear Information System (INIS)

    Neumaier, J.F.

    1989-01-01

    The role of endogenous opioid peptides as neurotransmitters in the rat hippocampus was investigated by using extracellular recording and radioligand binding techniques in the hippocampal slice preparation. Synaptic conductances from endogenously released opioid peptides have been difficult to detect. This problem was approach by designing a novel assay of opioid peptide release, in which release was detected by measuring binding competition between endogenous opioids and added radioligand. Membrane depolarization displaced [ 3 H]-diprenorphine binding in a transient, calcium-dependent, and peptidase-sensitive manner. Autoradiographic localization of the sites of [ 3 H]-diprenorphine binding displacement showed that significant opioid peptide release and receptor occupancy occurred in each major subregion of the hippocampal slices. This assay method can not be used to define optimal electrical stimulation conditions for releasing endogenous opioids. The binding displacement method was extended to the study of the sigma receptor. Depolarization of hippocampal slices was found to reduce the binding of the sigma-selective radioligand [ 3 H]-ditolylguanidine in a transient and calcium-dependent manner with no apparent direct effects on sigma receptor affinity

  20. Hypobaric Hypoxia Imbalances Mitochondrial Dynamics in Rat Brain Hippocampus

    Directory of Open Access Journals (Sweden)

    Khushbu Jain

    2015-01-01

    Full Text Available Brain is predominantly susceptible to oxidative stress and mitochondrial dysfunction during hypobaric hypoxia, and therefore undergoes neurodegeneration due to energy crisis. Evidences illustrate a high degree of association for mitochondrial fusion/fission imbalance and mitochondrial dysfunction. Mitochondrial fusion/fission is a recently reported dynamic mechanism which frequently occurs among cellular mitochondrial network. Hence, the study investigated the temporal alteration and involvement of abnormal mitochondrial dynamics (fusion/fission along with disturbed mitochondrial functionality during chronic exposure to hypobaric hypoxia (HH. The Sprague-Dawley rats were exposed to simulated high altitude equivalent to 25000 ft for 3, 7, 14, 21, and 28 days. Mitochondrial morphology, distribution within neurons, enzyme activity of respiratory complexes, Δψm, ADP: ATP, and expression of fission/fusion key proteins were determined. Results demonstrated HH induced alteration in mitochondrial morphology by damaged, small mitochondria observed in neurons with disturbance of mitochondrial functionality and reduced mitochondrial density in neuronal processes manifested by excessive mitochondrial fragmentation (fission and decreased mitochondrial fusion as compared to unexposed rat brain hippocampus. The study suggested that imbalance in mitochondrial dynamics is one of the noteworthy mechanisms occurring in hippocampal neurons during HH insult.

  1. Kinematics of suction feeding in the seahorse Hippocampus reidi.

    Science.gov (United States)

    Roos, Gert; Van Wassenbergh, Sam; Herrel, Anthony; Aerts, Peter

    2009-11-01

    Fish typically use a rostro-caudal wave of head expansion to generate suction, which is assumed to cause a uni-directional, anterior-to-posterior flow of water in the expanding head. However, compared with typical fish, syngnathid fishes have a remarkably different morphology (elongated snout, small hyoid, immobile pectoral girdle) and feeding strategy (pivot feeding: bringing the small mouth rapidly close to the prey by neurocranial dorsorotation). As a result, it is unclear how suction is generated in Syngnathidae. In this study, lateral and ventral expansions of the head were quantified in Hippocampus reidi and linked to the kinematics of the mouth, hyoid and neurocranium. In addition, the flow velocities inside the bucco-pharyngeal cavity and in front of the mouth were calculated. Our data suggest that the volume changes caused by lateral expansion are dominant over ventral expansion. Maximum gape, neurocranium rotation and hyoid depression are all reached before actual volume increase and before visible prey movement. This implies that, unlike previously studied teleosts, hyoid rotation does not contribute to ventral expansion by lowering the floor of the mouth during prey capture in H. reidi. The lateral volume changes show a rostro-caudal expansion, but the maximal flow velocity is not near the mouth aperture (as has been demonstrated for example in catfish) but at the narrow region of the buccal cavity, dorsal to the hyoid.

  2. Parental care improves immunity in the seahorse (Hippocampus erectus).

    Science.gov (United States)

    Lin, Tingting; Zhang, Dong; Liu, Xin; Xiao, Dongxue

    2016-11-01

    In the present study, the sexual dimorphism in immune response in the seahorse Hippocampus erectus in which males compete for mates and invest heavily in parental care was assessed. Variability in immunocompetence in virginal seahorses with differing levels of sexual maturity (i.e., immaturity, early maturity and maturity) and with different mating statuses (i.e., virginal, experienced mating failure and experienced mating success) were analyzed by evaluating immune parameters in the plasma. Additionally, ultrastructural characteristics of the inner epithelium of the brood pouch were compared between males that had experienced mating failure and those that had succeeded. Generally, immunity in sexually mature virgin males was greater than in females, and mating competition significantly reduced males' immunity. However, parental care gave males stronger immune and metabolic abilities and resulted in their immunity significantly rebounding after a successful mating. The present study quantitatively clarifies, for the first time, how parental care and mating competition jointly affect immunity. Moreover, previous findings that females display more efficient immune defenses than males in conventional species (i.e., males are as competitor and females as care giver) and that males' immunity is higher than females' in the pipefish (i.e., females are as competitor and males as care giver) in combination with the present results indicate that parental care is a key factor for sexual dimorphism in immunity. The care-giving sex has strong immunity regardless of the sex in charge of mating competition or not. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Seahorse (Hippocampus reidi) as a bioindicator of crude oil exposure.

    Science.gov (United States)

    Delunardo, Frederico Augusto Cariello; de Carvalho, Luciano Rodrigues; da Silva, Bruno Ferreira; Galão, Michel; Val, Adalberto Luís; Chippari-Gomes, Adriana R

    2015-07-01

    This study explored the suitability of the seahorse Hippocampus reidi (Ginsburg, 1933) for assessing biomarkers of genotoxic effects and its use as a sentinel organism to detect the effects of acute exposure to petroleum hydrocarbons. Fish were exposed to three concentrations of crude oil (10, 20 and 30 g/kg) for 96 h, and the activity of phase II biotransformation enzyme glutathione S-transferase (GST) was measured. In addition, we performed genotoxicity assays, such as comet assay, micronucleus (MN) test and nuclear abnormalities (NA) induction, on the erythrocytes of the fish species. Our results revealed that the inhibition of hepatic GST activity in H. reidi was dependent on increasing crude oil concentrations. In contrast, an increase in the damage index (DI) and MN frequency were observed with increased crude oil concentrations. These results indicate that the alkaline comet assay and micronucleus test were suitable and useful in the evaluation of the genotoxicity of crude oil, which could improve determinations of the impact of oil spills on fish populations. In addition, H. reidi is a promising "sentinel organism" to detect the genotoxic impact of petroleum hydrocarbons. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Genetic evidence for monogamy in the dwarf seahorse, Hippocampus zosterae.

    Science.gov (United States)

    Rose, Emily; Small, Clayton M; Saucedo, Hector A; Harper, Cristin; Jones, Adam G

    2014-01-01

    Syngnathid fishes (pipefishes, seahorses, and seadragons) exhibit a wide array of mating systems ranging from monogamy with long-term pair bonds to more promiscuous mating systems, such as polyandry and polygynandry. Some seahorses, including the dwarf seahorse Hippocampus zosterae, have been found to be socially monogamous. Although several seahorse species have also been shown to be genetically monogamous, parentage analysis has not yet been applied to the dwarf seahorse. We developed 8 novel microsatellites for the dwarf seahorse to conduct genetic parentage analysis to confirm that this species is indeed monogamous. Using 4 selected loci and a total of 16 pregnant male seahorses, with 8 collected in Florida and 8 sampled in Texas, we genotyped all of the offspring within each male's brood to determine the maternal contributions to each brood. We found a maximum of 4 alleles per locus segregating within each pregnant male's brood, a pattern consistent with each brood having exactly 1 mother and 1 father. These results support previous laboratory-based behavioral studies and indicate that the dwarf seahorse, H. zosterae, is genetically monogamous. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Longitudinal association between hippocampus atrophy and episodic-memory decline.

    Science.gov (United States)

    Gorbach, Tetiana; Pudas, Sara; Lundquist, Anders; Orädd, Greger; Josefsson, Maria; Salami, Alireza; de Luna, Xavier; Nyberg, Lars

    2017-03-01

    There is marked variability in both onset and rate of episodic-memory decline in aging. Structural magnetic resonance imaging studies have revealed that the extent of age-related brain changes varies markedly across individuals. Past studies of whether regional atrophy accounts for episodic-memory decline in aging have yielded inconclusive findings. Here we related 15-year changes in episodic memory to 4-year changes in cortical and subcortical gray matter volume and in white-matter connectivity and lesions. In addition, changes in word fluency, fluid IQ (Block Design), and processing speed were estimated and related to structural brain changes. Significant negative change over time was observed for all cognitive and brain measures. A robust brain-cognition change-change association was observed for episodic-memory decline and atrophy in the hippocampus. This association was significant for older (65-80 years) but not middle-aged (55-60 years) participants and not sensitive to the assumption of ignorable attrition. Thus, these longitudinal findings highlight medial-temporal lobe system integrity as particularly crucial for maintaining episodic-memory functioning in older age. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Rhythmic Working Memory Activation in the Human Hippocampus

    Directory of Open Access Journals (Sweden)

    Marcin Leszczyński

    2015-11-01

    Full Text Available Working memory (WM maintenance is assumed to rely on a single sustained process throughout the entire maintenance period. This assumption, although fundamental, has never been tested. We used intracranial electroencephalography (EEG recordings from the human hippocampus in two independent experiments to investigate the neural dynamics underlying WM maintenance. We observed periodic fluctuations between two different oscillatory regimes: Periods of “memory activation” were reflected by load-dependent alpha power reductions and lower levels of cross-frequency coupling (CFC. They occurred interleaved with periods characterized by load-independent high levels of alpha power and CFC. During memory activation periods, a relevant CFC parameter (load-dependent changes of the peak modulated frequency correlated with individual WM capacity. Fluctuations between these two periods predicted successful performance and were locked to the phase of endogenous delta oscillations. These results show that hippocampal maintenance is a dynamic rather than constant process and depends critically on a hierarchy of oscillations.

  7. 3H-spiroperidol labels serotonin receptors in rat cerebral cortex and hippocampus

    International Nuclear Information System (INIS)

    Creese, I.; Snyder, S.H.

    1978-01-01

    It is found that in the cerebral cortex, butaclamol displaceable 3 H-spiroperidol binding labels both dopamine and serotonin receptors. In the hippocampus it is probable that 3 H-spiroperidol binding involves serotonin receptors exclusively. (Auth.)

  8. Memory of music: roles of right hippocampus and left inferior frontal gyrus.

    Science.gov (United States)

    Watanabe, Takamitsu; Yagishita, Sho; Kikyo, Hideyuki

    2008-01-01

    We investigated neural correlates of retrieval success for music memory using event-related functional magnetic resonance imaging. To minimize the interference from MRI scan noise, we used sparse temporal sampling technique. Newly composed music materials were employed as stimuli, which enabled us to detect regions in absence of effects of experience with the music stimuli in this study. Whole brain analyses demonstrated significant retrieval success activities in the right hippocampus, bilateral lateral temporal regions, left inferior frontal gyrus and left precuneus. Anatomically defined region-of-interests analyses showed that the activity of the right hippocampus was stronger than that of the left, while the activities of the inferior frontal gyri showed the reverse pattern. Furthermore, performance-based analyses demonstrated that the retrieval success activity of the right hippocampus was positively correlated with the corrected recognition rate, suggesting that the right hippocampus contributes to the accuracy of music retrieval outcome.

  9. Time-dependent involvement of the dorsal hippocampus in trace fear conditioning in mice

    NARCIS (Netherlands)

    Misane, I.; Tovote, P.; Meyer, M.; Spiess, J.; Ögren, S.O.; Stiedl, O.

    2005-01-01

    Hippocampal and amygdaloid neuroplasticity are important substrates for Pavlovian fear conditioning. The hippocampus has been implicated in trace fear conditioning. However, a systematic investigation of the significance of the trace interval has not yet been performed. Therefore, this study

  10. Adult onset-hypothyroidism increases response latency and long-term potentiation (LTP) in rat hippocampus

    Science.gov (United States)

    Thyroid hormones (TH) influence central nervous system (CNS) function during both development and in adulthood. The hippocampus is critical for some types of learning and memory and is particularly sensitive to thyroid hormone deficiency. Hypothyroidism in adulthood has been ass...

  11. Inhibition of Rac1 Activity in the Hippocampus Impairs the Forgetting of Contextual Fear Memory.

    Science.gov (United States)

    Jiang, Lizhu; Mao, Rongrong; Zhou, Qixin; Yang, Yuexiong; Cao, Jun; Ding, Yuqiang; Yang, Yuan; Zhang, Xia; Li, Lingjiang; Xu, Lin

    2016-03-01

    Fear is crucial for survival, whereas hypermnesia of fear can be detrimental. Inhibition of the Rac GTPase is recently reported to impair the forgetting of initially acquired memory in Drosophila. Here, we investigated whether inhibition of Rac1 activity in rat hippocampus could contribute to the hypermnesia of contextual fear. We found that spaced but not massed training of contextual fear conditioning caused inhibition of Rac1 activity in the hippocampus and heightened contextual fear. Furthermore, intrahippocampal injection of the Rac1 inhibitor NSC23766 heightened contextual fear in massed training, while Rac1 activator CN04-A weakened contextual fear in spaced training rats. Our study firstly demonstrates that contextual fear memory in rats is actively regulated by Rac1 activity in the hippocampus, which suggests that the forgetting impairment of traumatic events in posttraumatic stress disorder may be contributed to the pathological inhibition of Rac1 activity in the hippocampus.

  12. Changes in acetylcholine content, release and muscarinic receptors in rat hippocampus under cold stress

    International Nuclear Information System (INIS)

    Fatranska, M.; Budai, D.; Gulya, K; Kvetnansky, R.

    1989-01-01

    The aim was to study the mechanism of the previously established decrease in acetylcholine (ACh) concentration in the rat hippocampus under cold stress. Male rats were exposed for 14 days to cold (5 degree C) or kept (controls) at room temperature (24 degree C). Acetylcholine content, release and muscarinic receptor binding were investigated in the hippocampus. Cold exposure resulted in a decrease of ACh concentration in the dorsal hippocampus. Moreover, the potassium-evoked release of ACh from hippocampal slices was increased and an increase of maximal binding capacity of [ 3 H](-) quinuclidinyl benzilate in the dorsal hippocampus of cold exposed animals was also observed. Thus the decrease of hippocampal ACh concentration under cold exposure is probably due to its increased release. On balance then, our results demonstrate that cold stress in the rat induces significant activation of the hippocampal cholinergic system

  13. Role of the hippocampus on learning and memory functioning and pain modulation

    Institute of Scientific and Technical Information of China (English)

    Haimei Wang

    2008-01-01

    The hippocampus, an important part of the limbic system, is considered to be an important region of the brain for learning and memory functioning. Recent studies have demonstrated that synaptic plasticity is thought to be the basis of learning and memory functioning. A series of studies report that similar synaptic plasticity also exists in the spinal cord in the conduction pathway of pain sensation, which may contribute to hyperalgesia, abnormal pain, and analgesia. The synaptic plasticity of learning and memory functioning and that of the pain conduction pathway have similar mechanisms, which are related to the N-methyl-D-aspartic acid receptor. The hippocampus also has a role in pain modulation. As pain signals can reach the hippocampus, the precise correlation between synaptic plasticity of the pain pathway and that of learning and memory functioning deserves further investigation. The role of the hippocampus in processing pain information requires to be identified.

  14. Volumetric MRI analysis of the amygdala and the hippocampus in patients with major depression

    International Nuclear Information System (INIS)

    Xia Jun; Zhou Yicheng; Zhang Jingfeng; Yang Bo; Xia Liming; Wang Chengyuan; Chen Jun

    2005-01-01

    Objective: To study the MRI volume of the amygdala and hippocampus in patients with major depression. Methods: Quantitative MRI of the amygdala and hippocampus was studied in 22 patients with major depression and compared with 13 age-matched controls. Results: Both groups exhibited similar significant hippocampal asymmetry (left smaller than right). The volume of the bilateral hippocampus was significantly smaller in the patient group than that in the controls (left: t=9.96, P<0.01; right: t=11.88, P<0.01). The right amygdala was smaller in the patient group than that in the control group (t=5.50, P<0.01), No correlation was found between the hippocampal volume abnormalities and the course of disease. Conclusion: These findings support the hypothesis that the hippocampus and amygdala within limbic-cortical networks may play a crucial role in the pathogenesis of major depression. (authors)

  15. High-LET Radiation-Induced Response of Microvessels in the Hippocampus

    Czech Academy of Sciences Publication Activity Database

    Mao, X. W.; Favre, C. J.; Fike, J. R.; Kubínová, Lucie; Anderson, E.; Campbell-Beachler, M.; Jones, T.; Smith, A.; Rightnar, S.; Nelson, G. A.

    2010-01-01

    Roč. 173, č. 4 (2010), s. 486-493 ISSN 0033-7587 Institutional research plan: CEZ:AV0Z50110509 Keywords : hippocampus * stereology * microvessels Subject RIV: EA - Cell Biology Impact factor: 2.578, year: 2010

  16. DEVELOPMENTAL HYPOTHYROIDISM ALTERS SYNAPTIC TRANSMISSION IN DENTATE GYRUS AND AREA CA1 OF HIPPOCAMPUS.

    Science.gov (United States)

    Hypothyroidism during critical periods of brain developmental leads to learning deficits and alterations in hippocampal structure. Neurophysiological properties of the hippocampus, however, have not been well characterized. The present study examined field potentials evoked in...

  17. Neuroprotective effect of pretreatment with ganoderma lucidum in cerebral ischemia/reperfusion injury in rat hippocampus

    Science.gov (United States)

    Zhang, Wangxin; Zhang, Quiling; Deng, Wen; Li, Yalu; Xing, Guoqing; Shi, Xinjun; Du, Yifeng

    2014-01-01

    Ganoderma lucidum is a traditional Chinese medicine, which has been shown to have both anti-oxidative and anti-inflammatory effects, and noticeably decreases both the infarct area and neuronal apoptosis of the ischemic cortex. This study aimed to investigate the protective effects and mechanisms of pretreatment with ganoderma lucidum (by intragastric administration) in cerebral ischemia/reperfusion injury in rats. Our results showed that pretreatment with ganoderma lucidum for 3 and 7 days reduced neuronal loss in the hippocampus, diminished the content of malondialdehyde in the hippocampus and serum, decreased the levels of tumor necrosis factor-α and interleukin-8 in the hippocampus, and increased the activity of superoxide dismutase in the hippocampus and serum. These results suggest that pretreatment with ganoderma lucidum was protective against cerebral ischemia/reperfusion injury through its anti-oxidative and anti-inflammatory actions. PMID:25317156

  18. Decreased BDNF levels in amygdala and hippocampus after intracerebroventricular administration of ouabain

    OpenAIRE

    Jornada, Luciano K.; Valvassori, Samira S.; Resende, Wilson R.; Moretti, Morgana; Ferreira, Camila L.; Fries, Gabriel R.; Kapczinski, Flavio; Quevedo, João

    2012-01-01

    OBJECTIVE: The present study aims to investigate the effects of ouabain intracerebroventricular injection on BDNF levels in the amygdala and hippocampus of Wistar rats. METHODS: Animals received a single intracerebroventricular injection of ouabain (10-3 and 10-2 M) or artificial cerebrospinal fluid and immediately, 1h, 24h, or seven days after injection, BDNF levels were measured in the rat's amygdala and hippocampus by sandwich-ELISA (n = 8 animals per group). RESULTS: When evaluated immedi...

  19. Loss of muscarinic receptors and of stimulated phospholipid labeling in ibotenate-treated hippocampus

    International Nuclear Information System (INIS)

    Fisher, S.K.; Frey, K.A.; Agranoff, B.W.

    1981-01-01

    The stimulation of phospholipid labeling by muscarinic agonists has been examined in nerve ending preparations from lesioned hippocampus in order to investigate the synaptic locus of the effect. Unilateral injections of the neurotoxin, ibotenic acid, into the hippocampus resulted in an extensive loss of nerve cells from both the dentate gyrus and hippocampus on the lesioned side and a parallel loss of muscarinic receptors as revealed by [ 3 H]quinuclidinyl benzilate autoradiography. Homogenates and nerve ending fractions prepared from the lesioned side of the hippocampus possessed a reduced specific activity (expressed per milligram of protein) of glutamic acid decarboxylase as well as a reduced number of muscarinic receptors compared with the control side. By contrast, choline acetyltransferase activity was either unchanged or slightly increased on the lesioned side. Although there was a reduced yield (25%) of nerve endings from the lesioned side, the specific activity of 32 Pi incorporation into phospholipids in the absence of added carbachol was comparable to that of the control side. There was, however, a marked reduction in the carbachol stimulation of phosphatidic acid and phosphatidylinositol labeling in nerve ending fractions obtained from he lesioned hippocampus. These results indicate that the muscarinic receptors present in nerve ending fractions from hippocampus and implicated in stimulated phospholipid turnover are derived from cholinoceptive intrinsic neurons

  20. Tracking the Time-Dependent Role of the Hippocampus in Memory Recall Using DREADDs.

    Science.gov (United States)

    Varela, Carmen; Weiss, Sarah; Meyer, Retsina; Halassa, Michael; Biedenkapp, Joseph; Wilson, Matthew A; Goosens, Ki Ann; Bendor, Daniel

    2016-01-01

    The hippocampus is critical for the storage of new autobiographical experiences as memories. Following an initial encoding stage in the hippocampus, memories undergo a process of systems-level consolidation, which leads to greater stability through time and an increased reliance on neocortical areas for retrieval. The extent to which the retrieval of these consolidated memories still requires the hippocampus is unclear, as both spared and severely degraded remote memory recall have been reported following post-training hippocampal lesions. One difficulty in definitively addressing the role of the hippocampus in remote memory retrieval is the precision with which the entire volume of the hippocampal region can be inactivated. To address this issue, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), a chemical-genetic tool capable of highly specific neuronal manipulation over large volumes of brain tissue. We find that remote (>7 weeks after acquisition), but not recent (1-2 days after acquisition) contextual fear memories can be recalled after injection of the DREADD agonist (CNO) in animals expressing the inhibitory DREADD in the entire hippocampus. Our data demonstrate a time-dependent role of the hippocampus in memory retrieval, supporting the standard model of systems consolidation.

  1. Normative volumetric data of the developing hippocampus in children based on magnetic resonance imaging.

    Science.gov (United States)

    Pfluger, T; Weil, S; Weis, S; Vollmar, C; Heiss, D; Egger, J; Scheck, R; Hahn, K

    1999-04-01

    To acquire normative data of the hippocampus and its postnatal growth in 50 children (age, 1 month to 15 years) without epilepsy. Morphometry of the hippocampus was carried out by using a spoiled FLASH 3D sequence (sagittal orientation), whereas the volume of the brain was assessed with a T2-weighted spin-echo sequence (transverse orientation). The volume of the hippocampus and the brain was determined by following Cavalieri's principle. Growth curves of the brain and hippocampus were fitted to a nonlinear Boltzmann sigmoidal equation. Intra-/interobserver coefficient of variation was 2.0/4.9% for hippocampal volume measurements and 2.0/2.1% for brain volumetry. A significant difference in volume was noted between the right and left hippocampus (p < 0.001), with the right side being larger on average by 0.10 cc. Correlation coefficients of growth curves ranged between 0.71 and 0.94. Growth curves demonstrated a faster development of the hippocampus in girls. A steeper slope of hippocampal growth as compared with brain growth was found in girls, whereas in boys, the slope of brain growth was steeper. Our findings will be of help in evaluating vulnerable phases of the hippocampal formation with accelerated growth, thereby leading to a better understanding of the development of hippocampal sclerosis in early childhood.

  2. What Representations and Computations Underpin the Contribution of the Hippocampus to Generalization and Inference?

    Directory of Open Access Journals (Sweden)

    Dharshan eKumaran

    2012-06-01

    Full Text Available Empirical research and theoretical accounts have traditionally emphasized the function of the hippocampus in episodic memory. Here we draw attention to the importance of the hippocampus to generalization, and focus on the neural representations and computations that might underpin its role in tasks such as the paired associate inference paradigm. We make a principal distinction between two different mechanisms by which the hippocampus may support generalization: an encoding-based mechanism that creates overlapping representations that capture higher-order relationships between different items (e.g. TCM – and a retrieval-based model (REMERGE that effectively computes these relationships at the point of retrieval, through a recurrent mechanism that allows the dynamic interaction of multiple pattern separated episodic codes. We also discuss what we refer to as transfer effects - a more abstract example of generalization that has also been linked to the function of the hippocampus. We consider how this phenomenon poses inherent challenges for models such as TCM and REMERGE, and outline the potential applicability of a separate class of models - hierarchical bayesian models (HBMs in this context. Our hope is that this article will provide a basic framework within which to consider the theoretical mechanisms underlying the role of the hippocampus in generalization, and at a minimum serve as a stimulus for future work addressing issues that go to the heart of the function of the hippocampus.

  3. Involvement Of BDNF In Age-Dependent Alterations In The Hippocampus

    Directory of Open Access Journals (Sweden)

    Oliver Von Bohlen Und Halbach

    2010-08-01

    Full Text Available It is known since a long time that the hippocampus is sensitive to aging. Thus, there is a reduction in the hippocampal volume during aging. This age-related volume reduction is paralleled by behavioral and functional deficits in hippocampus-dependent learning and memory tasks. This age-related volume reduction of the hippocampus is not a consequence of an age-related loss of hippocampal neurons. The morphological changes associated with aging include reductions in the branching pattern of dendrites, as well as reductions in spine-densities, reductions in the densities of fibers projecting into the hippocampus as well as declines in the rate of neurogenesis. It is very unlikely that a single factor or a single class of molecules is responsible for all these age-related morphological changes in the hippocampus. Nevertheless, it would be of advantage to identify possible neuromodulators or neuropeptides that may contribute to these age-related changes. In this context, growth factors may play an important role in the maintenance of the postnatal hippocampal architecture. In this review it is hypothesized that brain-derived neurotrophic factor (BDNF is a factor critically involved in the regulation of age-related processes in the hippocampus. Moreover, evidences suggest that disturbances in the BDNF-system also affect hippocampal dysfunctions, as e.g. seen in major depression or in Alzheimer disease.

  4. Sex, hormones and neurogenesis in the hippocampus: hormonal modulation of neurogenesis and potential functional implications.

    Science.gov (United States)

    Galea, L A M; Wainwright, S R; Roes, M M; Duarte-Guterman, P; Chow, C; Hamson, D K

    2013-11-01

    The hippocampus is an area of the brain that undergoes dramatic plasticity in response to experience and hormone exposure. The hippocampus retains the ability to produce new neurones in most mammalian species and is a structure that is targeted in a number of neurodegenerative and neuropsychiatric diseases, many of which are influenced by both sex and sex hormone exposure. Intriguingly, gonadal and adrenal hormones affect the structure and function of the hippocampus differently in males and females. Adult neurogenesis in the hippocampus is regulated by both gonadal and adrenal hormones in a sex- and experience-dependent way. Sex differences in the effects of steroid hormones to modulate hippocampal plasticity should not be completely unexpected because the physiology of males and females is different, with the most notable difference being that females gestate and nurse the offspring. Furthermore, reproductive experience (i.e. pregnancy and mothering) results in permanent changes to the maternal brain, including the hippocampus. This review outlines the ability of gonadal and stress hormones to modulate multiple aspects of neurogenesis (cell proliferation and cell survival) in both male and female rodents. The function of adult neurogenesis in the hippocampus is linked to spatial memory and depression, and the present review provides early evidence of the functional links between the hormonal modulation of neurogenesis that may contribute to the regulation of cognition and stress. © 2013 British Society for Neuroendocrinology.

  5. The hippocampus supports multiple cognitive processes through relational binding and comparison

    Directory of Open Access Journals (Sweden)

    Rosanna Kathleen Olsen

    2012-05-01

    Full Text Available It has been well established that the hippocampus plays a pivotal role in explicit long-term recognition memory. However, findings from amnesia, lesion and recording studies with non-human animals, eye-movement recording studies, and functional neuroimaging have recently converged upon a similar message: the functional reach of the hippocampus extends far beyond explicit recognition memory. Damage to the hippocampus affects performance on a number of cognitive tasks including recognition memory after short and long delays and visual discrimination. Additionally, with the advent of neuroimaging techniques that have fine spatial and temporal resolution, findings have emerged that show the elicitation of hippocampal responses within the first few hundred milliseconds of stimulus/task onset. These responses occur for novel and previously viewed information during a time when perceptual processing is traditionally thought to occur, and long before overt recognition responses are made. We propose that the hippocampus is obligatorily involved in the binding of disparate elements across both space and time, and in the comparison of such relational memory representations. Furthermore, the hippocampus supports relational binding and comparison with or without conscious awareness for the relational representations that are formed, retrieved and/or compared. It is by virtue of these basic binding and comparison functions that the reach of the hippocampus extends beyond long-term recognition memory and underlies task performance in multiple cognitive domains.

  6. Adult neurogenesis is reduced in the dorsal hippocampus of rats displaying learned helplessness behavior.

    Science.gov (United States)

    Ho, Y C; Wang, S

    2010-11-24

    Clinical and preclinical studies suggest that the hippocampus has a role in the pathophysiology of major depression. In the learned helplessness (LH) animal model of depression after inescapable shocks (ISs) animals that display LH behavior have reduced cell proliferation in the hippocampus; this effect can be reversed by antidepressant treatment. Using this model, we compared rats that displayed LH behavior and rats that did not show LH behavior (NoLH) after ISs to determine whether reduced hippocampal cell proliferation is associated with the manifestation of LH behavior or is a general response to stress. Specifically, we examined cell proliferation, neurogenesis, and synaptic function in dorsal and ventral hippocampus of LH and NoLH animals and control rats that were not shocked. The LH rats had showed reduced cell proliferation, neurogenesis, and synaptic transmission in the dorsal hippocampus, whereas no changes were seen in the ventral hippocampus. These changes were not observed in the NoLH animals. In a group of NoLH rats that received the same amount of electrical shock as the LH rats to control for the unequal shocks received in these two groups, we observed changes in Ki-67(+) cells associated with acute stress. We conclude that reduced hippocampal cell proliferation and neurogenesis are associated with the manifestation of LH behavior and that the dorsal hippocampus is the most affected area. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Implicit transitive inference and the human hippocampus: does intravenous midazolam function as a reversible hippocampal lesion?

    Directory of Open Access Journals (Sweden)

    Greene Anthony J

    2007-09-01

    Full Text Available Abstract Recent advances have led to an understanding that the hippocampus is involved more broadly than explicit or declarative memory alone. Tasks which involve the acquisition of complex associations involve the hippocampus whether the learning is explicit or implicit. One hippocampal-dependent implicit task is transitive inference (TI. Recently it was suggested that implicit transitive inference does not depend upon the hippocampus (Frank, M. J., O'Reilly, R. C., & Curran, T. 2006. When memory fails, intuition reigns: midazolam enhances implicit inference in humans. Psychological Science, 17, 700–707. The authors demonstrated that intravenous midazolam, which is thought to inactivate the hippocampus, may enhance TI performance. Three critical assumptions are required but not met: 1 that deactivations of other regions could not account for the effect 2 that intravenous midazolam does indeed deactivate the hippocampus and 3 that midazolam influences explicit but not implicit memory. Each of these assumptions is seriously flawed. Consequently, the suggestion that implicit TI does not depend upon the hippocampus is unfounded.

  8. A kinetic study of the in vivo incorporation of 65Zn into the rat hippocampus

    International Nuclear Information System (INIS)

    Sato, S.M.; Frazier, J.M.; Goldberg, A.M.

    1984-01-01

    Previous autoradiographical studies utilizing 65 Zn demonstrated an apparent concentration of 65 Zn in the mossy fiber boutons of the hippocampus. To examine the speciation of the 65 Zn pool found in this neuronal pathway, we investigated the in vivo incorporation of systemic 65 Zn into rat hippocampus compared with other brain regions. We were especially interested in kinetically assessing the zinc associated with three previously identified cytosolic zinc-binding species found in the hippocampus. The hypothesis that two of these cytosolic zinc-binding species, a metallothionein-like protein and a putative zinc-glutathione complex, may be responsible for the sequestration of zinc in the hippocampus was tested. It was confirmed that the t 1/2 of hippocampal zinc is longer than other brain regions that were studied. Furthermore, we observed that 65 Zn is incorporated into three cytosolic zinc-binding species in the hippocampus as resolved using Ultrogel AcA 34 gel permeation chromatography. One of these species, the putative zinc-glutathione complex, accumulates zinc more slowly than the other species. The data suggest that the putative zinc-glutathione complex may represent an important 65 Zn pool in the hippocampus. This finding is in accordance with out hypothesis that a zinc-binding species, specifically, the putative zinc-glutathione complex, may be responsible for the sequestration of zinc in the hippocampal mossy boutons

  9. Genetic variations in two seahorse species (Hippocampus mohnikei and Hippocampus trimaculatus): evidence for middle Pleistocene population expansion.

    Science.gov (United States)

    Zhang, Yanhong; Pham, Nancy Kim; Zhang, Huixian; Lin, Junda; Lin, Qiang

    2014-01-01

    Population genetic of seahorses is confidently influenced by their species-specific ecological requirements and life-history traits. In the present study, partial sequences of mitochondrial cytochrome b (cytb) and control region (CR) were obtained from 50 Hippocampus mohnikei and 92 H. trimaculatus from four zoogeographical zones. A total of 780 base pairs of cytb gene were sequenced to characterize mitochondrial DNA (mtDNA) diversity. The mtDNA marker revealed high haplotype diversity, low nucleotide diversity, and a lack of population structure across both populations of H. mohnikei and H. trimaculatus. A neighbour-joining (NJ) tree of cytb gene sequences showed that H. mohnikei haplotypes formed one cluster. A maximum likelihood (ML) tree of cytb gene sequences showed that H. trimaculatus belonged to one lineage. The star-like pattern median-joining network of cytb and CR markers indicated a previous demographic expansion of H. mohnikei and H. trimaculatus. The cytb and CR data sets exhibited a unimodal mismatch distribution, which may have resulted from population expansion. Mismatch analysis suggested that the expansion was initiated about 276,000 years ago for H. mohnikei and about 230,000 years ago for H. trimaculatus during the middle Pleistocene period. This study indicates a possible signature of genetic variation and population expansion in two seahorses under complex marine environments.

  10. Genetic variations in two seahorse species (Hippocampus mohnikei and Hippocampus trimaculatus: evidence for middle Pleistocene population expansion.

    Directory of Open Access Journals (Sweden)

    Yanhong Zhang

    Full Text Available Population genetic of seahorses is confidently influenced by their species-specific ecological requirements and life-history traits. In the present study, partial sequences of mitochondrial cytochrome b (cytb and control region (CR were obtained from 50 Hippocampus mohnikei and 92 H. trimaculatus from four zoogeographical zones. A total of 780 base pairs of cytb gene were sequenced to characterize mitochondrial DNA (mtDNA diversity. The mtDNA marker revealed high haplotype diversity, low nucleotide diversity, and a lack of population structure across both populations of H. mohnikei and H. trimaculatus. A neighbour-joining (NJ tree of cytb gene sequences showed that H. mohnikei haplotypes formed one cluster. A maximum likelihood (ML tree of cytb gene sequences showed that H. trimaculatus belonged to one lineage. The star-like pattern median-joining network of cytb and CR markers indicated a previous demographic expansion of H. mohnikei and H. trimaculatus. The cytb and CR data sets exhibited a unimodal mismatch distribution, which may have resulted from population expansion. Mismatch analysis suggested that the expansion was initiated about 276,000 years ago for H. mohnikei and about 230,000 years ago for H. trimaculatus during the middle Pleistocene period. This study indicates a possible signature of genetic variation and population expansion in two seahorses under complex marine environments.

  11. Neurons of the dentate molecular layer in the rabbit hippocampus.

    Directory of Open Access Journals (Sweden)

    Francisco J Sancho-Bielsa

    Full Text Available The molecular layer of the dentate gyrus appears as the main entrance gate for information into the hippocampus, i.e., where the perforant path axons from the entorhinal cortex synapse onto the spines and dendrites of granule cells. A few dispersed neuronal somata appear intermingled in between and probably control the flow of information in this area. In rabbits, the number of neurons in the molecular layer increases in the first week of postnatal life and then stabilizes to appear permanent and heterogeneous over the individuals' life span, including old animals. By means of Golgi impregnations, NADPH histochemistry, immunocytochemical stainings and intracellular labelings (lucifer yellow and biocytin injections, eight neuronal morphological types have been detected in the molecular layer of developing adult and old rabbits. Six of them appear as interneurons displaying smooth dendrites and GABA immunoreactivity: those here called as globoid, vertical, small horizontal, large horizontal, inverted pyramidal and polymorphic. Additionally there are two GABA negative types: the sarmentous and ectopic granular neurons. The distribution of the somata and dendritic trees of these neurons shows preferences for a definite sublayer of the molecular layer: small horizontal, sarmentous and inverted pyramidal neurons are preferably found in the outer third of the molecular layer; vertical, globoid and polymorph neurons locate the intermediate third, while large horizontal and ectopic granular neurons occupy the inner third or the juxtagranular molecular layer. Our results reveal substantial differences in the morphology and electrophysiological behaviour between each neuronal archetype in the dentate molecular layer, allowing us to propose a new classification for this neural population.

  12. Draft genome of the lined seahorse, Hippocampus erectus.

    Science.gov (United States)

    Lin, Qiang; Qiu, Ying; Gu, Ruobo; Xu, Meng; Li, Jia; Bian, Chao; Zhang, Huixian; Qin, Geng; Zhang, Yanhong; Luo, Wei; Chen, Jieming; You, Xinxin; Fan, Mingjun; Sun, Min; Xu, Pao; Venkatesh, Byrappa; Xu, Junming; Fu, Hongtuo; Shi, Qiong

    2017-06-01

    The lined seahorse, Hippocampus erectus , is an Atlantic species and mainly inhabits shallow sea beds or coral reefs. It has become very popular in China for its wide use in traditional Chinese medicine. In order to improve the aquaculture yield of this valuable fish species, we are trying to develop genomic resources for assistant selection in genetic breeding. Here, we provide whole genome sequencing, assembly, and gene annotation of the lined seahorse, which can enrich genome resource and further application for its molecular breeding. A total of 174.6 Gb (Gigabase) raw DNA sequences were generated by the Illumina Hiseq2500 platform. The final assembly of the lined seahorse genome is around 458 Mb, representing 94% of the estimated genome size (489 Mb by k-mer analysis). The contig N50 and scaffold N50 reached 14.57 kb and 1.97 Mb, respectively. Quality of the assembled genome was assessed by BUSCO with prediction of 85% of the known vertebrate genes and evaluated using the de novo assembled RNA-seq transcripts to prove a high mapping ratio (more than 99% transcripts could be mapped to the assembly). Using homology-based, de novo and transcriptome-based prediction methods, we predicted 20 788 protein-coding genes in the generated assembly, which is less than our previously reported gene number (23 458) of the tiger tail seahorse ( H. comes ). We report a draft genome of the lined seahorse. These generated genomic data are going to enrich genome resource of this economically important fish, and also provide insights into the genetic mechanisms of its iconic morphology and male pregnancy behavior. © The Authors 2017. Published by Oxford University Press.

  13. Theta coordinated error-driven learning in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Nicholas Ketz

    Full Text Available The learning mechanism in the hippocampus has almost universally been assumed to be Hebbian in nature, where individual neurons in an engram join together with synaptic weight increases to support facilitated recall of memories later. However, it is also widely known that Hebbian learning mechanisms impose significant capacity constraints, and are generally less computationally powerful than learning mechanisms that take advantage of error signals. We show that the differential phase relationships of hippocampal subfields within the overall theta rhythm enable a powerful form of error-driven learning, which results in significantly greater capacity, as shown in computer simulations. In one phase of the theta cycle, the bidirectional connectivity between CA1 and entorhinal cortex can be trained in an error-driven fashion to learn to effectively encode the cortical inputs in a compact and sparse form over CA1. In a subsequent portion of the theta cycle, the system attempts to recall an existing memory, via the pathway from entorhinal cortex to CA3 and CA1. Finally the full theta cycle completes when a strong target encoding representation of the current input is imposed onto the CA1 via direct projections from entorhinal cortex. The difference between this target encoding and the attempted recall of the same representation on CA1 constitutes an error signal that can drive the learning of CA3 to CA1 synapses. This CA3 to CA1 pathway is critical for enabling full reinstatement of recalled hippocampal memories out in cortex. Taken together, these new learning dynamics enable a much more robust, high-capacity model of hippocampal learning than was available previously under the classical Hebbian model.

  14. The study of the volume and 1H MRS of the hippocampus in posttraumatic stress disorder

    International Nuclear Information System (INIS)

    Yang Bo; Zhou Yicheng; Xia Jun; Xia Liming; Wang Chengyuan

    2006-01-01

    Objective: To study the changes of the hippocampus metabolites and the hippoeampus volume with MRI, and to explore the posibble pathophysiology of the hippocampus injure in posttraumatic stress disorder(PTSD). Methods: Seventeen cases of PTSD and 17 age-matched normal subjects (control subjects) were examined on a clinical 1.5 T MRI/MRS system. Proton multi-voxel spectroscopy imaging ( 1 H-MRSI) was obtained from two sides of the hippocampus region. The metabolites included N-acetylaspartate (NAA), creatine and phosphocreatine (Cr), and choline-containing compounds (Cho). The values of NAA, Cr, and Cho were calculated by integration of their peaks. The volume of the hippocampus of the two sides and the brain volume were measured with volume analysis software, and the resulting data were normalized according to the individual brain volume. Both the value of the metabolites and volume of the hippocampus were compared between the two groups respectively. Results: The volumes of left and right hippocampus were (2130±221 )mm 3 and (2571±190) mm 3 in PTSD cases, and they were (2382±157) mm 3 and (2572±186) mm 3 in the control subjects. The volume of left hippocampus of PTSD was smaller than that of the control subjects (P 0.05). NAA and Cr was significantly reduced in PTSD (Left: NAA= 2.8±0.7, Cr=2.3±0.6; Right: NAA 2.9±0.9, Cr=2.3±0.7) bilaterally when compared with those of control subjects (Left: NAA=3.8±0.8, Cr=2.7±0.5; Right: NAA=3.9±0.8, Cr=2.8±0.5) (P 0.05). Conclusion: The results of this study add support to the view that the hippocampus may participate in the pathophysiology of PTSD, and the findings of volume and metabolite changes in the hippocampus has great value in diagnosing PTSD and in exploring the posibble pathophysiology mechanisms of hippocampus injure in PTSD. (authors)

  15. The ventral hippocampus, but not the dorsal hippocampus is critical for learned approach-avoidance decision making.

    Science.gov (United States)

    Schumacher, Anett; Vlassov, Ekaterina; Ito, Rutsuko

    2016-04-01

    The resolution of an approach-avoidance conflict induced by ambivalent information involves the appraisal of the incentive value of the outcomes and associated stimuli to orchestrate an appropriate behavioral response. Much research has been directed at delineating the neural circuitry underlying approach motivation and avoidance motivation separately. Very little research, however, has examined the neural substrates engaged at the point of decision making when opposing incentive motivations are experienced simultaneously. We hereby examine the role of the dorsal and ventral hippocampus (HPC) in a novel approach-avoidance decision making paradigm, revisiting a once popular theory of HPC function, which posited the HPC to be the driving force of a behavioral inhibition system that is activated in situations of imminent threat. Rats received pre-training excitotoxic lesions of the dorsal or ventral HPC, and were trained to associate different non-spatial cues with appetitive, aversive and neutral outcomes in three separate arms of the radial maze. On the final day of testing, a state of approach-avoidance conflict was induced by simultaneously presenting two cues of opposite valences, and comparing the time the rats spent interacting with the superimposed 'conflict' cue, and the neutral cue. The ventral HPC-lesioned group showed significant preference for the conflict cue over the neutral cue, compared to the dorsal HPC-lesioned, and control groups. Thus, we provide evidence that the ventral, but not dorsal HPC, is a crucial component of the neural circuitry concerned with exerting inhibitory control over approach tendencies under circumstances in which motivational conflict is experienced. © 2015 Wiley Periodicals, Inc.

  16. Structural layers of ex vivo rat hippocampus at 7T MRI.

    Directory of Open Access Journals (Sweden)

    Jeanine Manuella Kamsu

    Full Text Available Magnetic resonance imaging (MRI applied to the hippocampus is challenging in studies of the neurophysiology of memory and the physiopathology of numerous diseases such as epilepsy, Alzheimer's disease, ischemia, and depression. The hippocampus is a well-delineated cerebral structure with a multi-layered organization. Imaging of hippocampus layers is limited to a few studies and requires high magnetic field and gradient strength. We performed one conventional MRI sequence on a 7T MRI in order to visualize and to delineate the multi-layered hippocampal structure ex vivo in rat brains. We optimized a volumic three-dimensional T2 Rapid Acquisition Relaxation Enhancement (RARE sequence and quantified the volume of the hippocampus and one of its thinnest layers, the stratum granulare of the dentate gyrus. Additionally, we tested passive staining by gadolinium with the aim of decreasing the acquisition time and increasing image contrast. Using appropriated settings, six discrete layers were differentiated within the hippocampus in rats. In the hippocampus proper or Ammon's Horn (AH: the stratum oriens, the stratum pyramidale of, the stratum radiatum, and the stratum lacunosum moleculare of the CA1 were differentiated. In the dentate gyrus: the stratum moleculare and the stratum granulare layer were seen distinctly. Passive staining of one brain with gadolinium decreased the acquisition time by four and improved the differentiation between the layers. A conventional sequence optimized on a 7T MRI with a standard receiver surface coil will allow us to study structural layers (signal and volume of hippocampus in various rat models of neuropathology (anxiety, epilepsia, neurodegeneration.

  17. Methamphetamine differentially affects BDNF and cell death factors in anatomically defined regions of the hippocampus

    Science.gov (United States)

    Galinato, Melissa H.; Orio, Laura; Mandyam, Chitra D.

    2014-01-01

    Methamphetamine exposure reduces hippocampal long-term potentiation (LTP) and neurogenesis and these alterations partially contribute to hippocampal maladaptive plasticity. The potential mechanisms underlying methamphetamine-induced maladaptive plasticity were identified in the present study. Expression of brain-derived neurotrophic factor (BDNF; a regulator of LTP and neurogenesis), and its receptor tropomyosin-related kinase B (TrkB) were studied in the dorsal and ventral hippocampal tissue lysates in rats that intravenously self-administered methamphetamine in a limited access (1 h/day) or extended access (6 h/day) paradigm for 17 days post baseline sessions. Extended access methamphetamine enhanced expression of BDNF with significant effects observed in the dorsal and ventral hippocampus. Methamphetamine-induced enhancements in BDNF expression were not associated with TrkB receptor activation as indicated by phospho (p)-TrkB-706 levels. Conversely, methamphetamine produced hypophosphorylation of NMDA receptor subunit 2B (GluN2B) at Tyr-1472 in the ventral hippocampus, indicating reduced receptor activation. In addition, methamphetamine enhanced expression of anti-apoptotic protein Bcl-2 and reduced pro-apoptotic protein Bax levels in the ventral hippocampus, suggesting a mechanism for reducing cell death. Analysis of Akt, a pro-survival kinase that suppresses apoptotic pathways and pAkt at Ser-473 demonstrated that extended access methamphetamine reduces Akt expression in the ventral hippocampus. These data reveal that alterations in Bcl-2 and Bax levels by methamphetamine were not associated with enhanced Akt expression. Given that hippocampal function and neurogenesis vary in a subregion-specific fashion, where dorsal hippocampus regulates spatial processing and has higher levels of neurogenesis, whereas ventral hippocampus regulates anxiety-related behaviors, these data suggest that methamphetamine self-administration initiates distinct allostatic changes in

  18. Rounding of the hippocampus in Alzheimer's disease. A study by routine coronal magnetic resonance imaging

    International Nuclear Information System (INIS)

    Adachi, Michito; Ohshima, Fumi; Kawanami, Toru; Kawakatsu, Shinobu; Shibata, Akiko

    2007-01-01

    On routine coronal images, we have recognized atrophied hippocampi that appear round in patients with Alzheimer's disease (AD). The purpose of this study was to evaluate rounding of the hippocampus in patients with AD and to elucidate whether this change is a useful radiological marker of atrophy of the hippocampus. We enrolled 14 patients with moderate AD (Mini-Mental State Examination score 16.2±3.3) and 15 patients without dementia or neurological deficits as the control group. For measurement of the hippocampus, we used T2-weighted coronal images parallel to the floor of the fourth ventricle. Two observers measured the dimensions of the long and short axes of the hippocampal body of 28 hippocampi from 14 patients with AD and 30 hippocampi from 15 controls. As a marker of rounding of the hippocampal body, we calculated the ratio of the short axis length to the long axis length (the rounding ratio) of the hippocampus. We observed apparent atrophy of the long axis of the hippocampus in patients with AD. An unpaired t-test indicated significant differences in the long axis length and the rounding ratio between the control and AD groups (P<0.01) in the measurements of both observers. However, there was no significant difference in the short axis length. With a threshold of 0.7 in the rounding ratio, the sensitivity was 85.7% and the specificity was 66.7%. The hippocampus appears round on coronal images in the presence of moderate AD. The rounding ratio of the hippocampus is a useful and facile indicator of hippocampal atrophy. (author)

  19. Neuropathological Changes in Brain Cortex and Hippocampus in a Rat Model of Alzheimer’s Disease

    Science.gov (United States)

    Nobakht, Maliheh; Hoseini, Seyed Mohammad; Mortazavi, Pejman; Sohrabi, Iraj; Esmailzade, Banafshe; Roosh, Nahid Rahbar; Omidzahir, Shila

    2011-01-01

    Background: Alzheimer’s disease (AD) is a neurodegenerative disorder with progressive loss of cognitive abilities and memory loss. The aim of this study was to compare neuropathological changes in hippocampus and brain cortex in a rat model of AD. Methods: Adult male Albino Wistar rats (weighing 250-300 g) were used for behavioral and histopathological studies. The rats were randomly assigned to three groups: control, sham and β-amyloid (Aβ) injection. For behavioral analysis, Y-maze and shuttle box were used, respectively at 14 and 16 days post-lesion. For histological studies, Nissl, modified Bielschowsky and modified Congo red staining were performed. The lesion was induced by injection of 4 µL of Aβ (1-40) into the hippocampal fissure. Results: In the present study, Aβ (1-40) injection into hippocampus could decrease the behavioral indexes and the number of CA1 neurons in hippocampus. Aβ injection CA1 caused Aβ deposition in the hippocampus and less than in cortex. We observed the loss of neurons in the hippocampus and cerebral cortex and certain subcortical regions. Y-maze test and single-trial passive avoidance test showed reduced memory retention in AD group. Conclusion: We found a significant decreased acquisition of passive avoidance and alternation behavior responses in AD group compared to control and sham group (P<0.0001). Compacted amyloid cores were present in the cerebral cortex, hippocampus and white matter, whereas, scattered amyloid cores were seen in cortex and hippocampus of AD group. Also, reduced neuronal density was indicated in AD group. PMID:21725500

  20. Neuropathological changes in brain cortex and hippocampus in a rat model of Alzheimer's disease.

    Science.gov (United States)

    Nobakht, Maliheh; Hoseini, Seyed Mohammad; Mortazavi, Pejman; Sohrabi, Iraj; Esmailzade, Banafshe; Rahbar Rooshandel, Nahid; Omidzahir, Shila

    2011-01-01

    Alzheimer's disease (AD) is a neurodegenerative disorder with progressive loss of cognitive abilities and memory loss. The aim of this study was to compare neuropathological changes in hippocampus and brain cortex in a rat model of AD. Adult male Albino Wistar rats (weighing 250-300 g) were used for behavioral and histopathological studies. The rats were randomly assigned to three groups: control, sham and Beta amyloid (ABeta) injection. For behavioral analysis, Y-maze and shuttle box were used, respectively at 14 and 16 days post-lesion. For histological studies, Nissl, modified Bielschowsky and modified Congo red staining were performed. The lesion was induced by injection of 4 muL of ABeta (1-40) into the hippocampal fissure. In the present study, ABeta (1-40) injection into hippocampus could decrease the behavioral indexes and the number of CA1 neurons in hippocampus. ABeta injection CA1 caused ABeta deposition in the hippocampus and less than in cortex. We observed the loss of neurons in the hippocampus and cerebral cortex and certain subcortical regions. Y-maze test and single-trial passive avoidance test showed reduced memory retention in AD group. We found a significant decreased acquisition of passive avoidance and alternation behavior responses in AD group compared to control and sham group (P<0.0001). Compacted amyloid cores were present in the cerebral cortex, hippocampus and white matter, whereas, scattered amyloid cores were seen in cortex and hippocampus of AD group. Also, reduced neuronal density was indicated in AD group.

  1. Long-term aerobic exercise increases redox-active iron through nitric oxide in rat hippocampus.

    Science.gov (United States)

    Chen, Qian; Xiao, De-Sheng

    2014-01-30

    Adult hippocampus is highly vulnerable to iron-induced oxidative stress. Aerobic exercise has been proposed to reduce oxidative stress but the findings in the hippocampus are conflicting. This study aimed to observe the changes of redox-active iron and concomitant regulation of cellular iron homeostasis in the hippocampus by aerobic exercise, and possible regulatory effect of nitric oxide (NO). A randomized controlled study was designed in the rats with swimming exercise treatment (for 3 months) and/or an unselective inhibitor of NO synthase (NOS) (L-NAME) treatment. The results from the bleomycin-detectable iron assay showed additional redox-active iron in the hippocampus by exercise treatment. The results from nonheme iron content assay, combined with the redox-active iron content, showed increased storage iron content by exercise treatment. NOx (nitrate plus nitrite) assay showed increased NOx content by exercise treatment. The results from the Western blot assay showed decreased ferroportin expression, no changes of TfR1 and DMT1 expressions, increased IRP1 and IRP2 expression, increased expressions of eNOS and nNOS rather than iNOS. In these effects of exercise treatment, the increased redox-active iron content, storage iron content, IRP1 and IRP2 expressions were completely reversed by L-NAME treatment, and decreased ferroportin expression was in part reversed by L-NAME. L-NAME treatment completely inhibited increased NOx and both eNOS and nNOS expression in the hippocampus. Our findings suggest that aerobic exercise could increase the redox-active iron in the hippocampus, indicating an increase in the capacity to generate hydroxyl radicals through the Fenton reactions, and aerobic exercise-induced iron accumulation in the hippocampus might mainly result from the role of the endogenous NO. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Neurosteroids in Adult Hippocampus of Male and Female Rodents: Biosynthesis and Actions of Sex Steroids

    Directory of Open Access Journals (Sweden)

    Yasushi Hojo

    2018-04-01

    Full Text Available The brain is not only the target of steroid hormones but also is able to locally synthesize steroids de novo. Evidence of the local production of steroids in the brain has been accumulating in various vertebrates, including teleost fish, amphibia, birds, rodents, non-human primates, and humans. In this review, we mainly focus on the local production of sex steroids in the hippocampal neurons of adult rodents (rats and mice, a center for learning and memory. From the data of the hippocampus of adult male rats, hippocampal principal neurons [pyramidal cells in CA1–CA3 and granule cells in dentate gyrus (DG] have a complete system for biosynthesis of sex steroids. Liquid chromatography with tandem-mass-spectrometry (LC-MS/MS enabled us to accurately determine the levels of hippocampal sex steroids including 17β-estradiol (17β-E2, testosterone (T, and dihydrotestosterone (DHT, which are much higher than those in blood. Next, we review the steroid synthesis in the hippocampus of female rats, since previous knowledge had been biased toward the data from males. Recently, we clarified that the levels of hippocampal steroids fluctuate in adult female rats across the estrous cycle. Accurate determination of hippocampal steroids at each stage of the estrous cycle is of importance for providing the account for the fluctuation of female hippocampal functions, including spine density, long-term potentiation (LTP and long-term depression (LTD, and learning and memory. These functional fluctuations in female had been attributed to the level of circulation-derived steroids. LC-MS/MS analysis revealed that the dendritic spine density in CA1 of adult female hippocampus correlates with the levels of hippocampal progesterone and 17β-E2. Finally, we introduce the direct evidence of the role of hippocampus-synthesized steroids in hippocampal function including neurogenesis, LTP, and memory consolidation. Mild exercise (2 week of treadmill running elevated

  3. Julius Caesar Arantius (Giulio Cesare Aranzi, 1530-1589) and the hippocampus of the human brain: history behind the discovery.

    Science.gov (United States)

    Bir, Shyamal C; Ambekar, Sudheer; Kukreja, Sunil; Nanda, Anil

    2015-04-01

    Julius Caesar Arantius is one of the pioneer anatomists and surgeons of the 16th century who discovered the different anatomical structures of the human body. One of his prominent discoveries is the hippocampus. At that time, Arantius originated the term hippocampus, from the Greek word for seahorse (hippos ["horse"] and kampos ["sea monster"]). Arantius published his description of the hippocampus in 1587, in the first chapter of his work titled De Humano Foetu Liber. Numerous nomenclatures of this structure, including "white silkworm," "Ammon's horn," and "ram's horn" were proposed by different scholars at that time. However, the term hippocampus has become the most widely used in the literature.

  4. Neurocomputational account of memory and perception: Thresholded and graded signals in the hippocampus.

    Science.gov (United States)

    Elfman, Kane W; Aly, Mariam; Yonelinas, Andrew P

    2014-12-01

    Recent evidence suggests that the hippocampus, a region critical for long-term memory, also supports certain forms of high-level visual perception. A seemingly paradoxical finding is that, unlike the thresholded hippocampal signals associated with memory, the hippocampus produces graded, strength-based signals in perception. This article tests a neurocomputational model of the hippocampus, based on the complementary learning systems framework, to determine if the same model can account for both memory and perception, and whether it produces the appropriate thresholded and strength-based signals in these two types of tasks. The simulations showed that the hippocampus, and most prominently the CA1 subfield, produced graded signals when required to discriminate between highly similar stimuli in a perception task, but generated thresholded patterns of activity in recognition memory. A threshold was observed in recognition memory because pattern completion occurred for only some trials and completely failed to occur for others; conversely, in perception, pattern completion always occurred because of the high degree of item similarity. These results offer a neurocomputational account of the distinct hippocampal signals associated with perception and memory, and are broadly consistent with proposals that CA1 functions as a comparator of expected versus perceived events. We conclude that the hippocampal computations required for high-level perceptual discrimination are congruous with current neurocomputational models that account for recognition memory, and fit neatly into a broader description of the role of the hippocampus for the processing of complex relational information. © 2014 Wiley Periodicals, Inc.

  5. Elliptic Fourier Analysis of body shape variation of Hippocampus spp. (seahorse in Danajon Bank, Philippines

    Directory of Open Access Journals (Sweden)

    S. R. M. Tabugo-Rico

    2017-12-01

    Full Text Available Seahorses inhabit various ecosystems hence, had become a flagship species of the marine environment. The Philippines as a hot spot of biodiversity in Asia holds a number of species of seahorses. This serve as an exploratory study to describe body shape variation of selected common seahorse species: Hippocampus comes, Hippocampus histrix, Hippocampus spinosissimus and Hippocampus kuda from Danajon bank using Elliptic Fourier Analysis. The method was done to test whether significant yet subtle differences in body shape variation can be species-specific, habitat-influenced and provide evidence of sexual dimorphism. It is hypothesized that phenotypic divergence may provide evidence for genetic differentiation or mere adaptations to habitat variation. Results show significant considerable differences in the body shapes of the five populations based on the canonical variate analysis (CVA and multivariate analysis of variance (MANOVA with significant p values. Populations were found to be distinct from each other suggesting that body shape variation is species-specific, habitat-influenced and provided evidence for sexual dimorphism. Results of discriminant analysis show further support for species specific traits and sexual dimorphism. This study shows the application of the method of geometric morphometrics specifically elliptic fourier analysis in describing subtle body shape variation of selected Hippocampus species.

  6. Novel experience induces persistent sleep-dependent plasticity in the cortex but not in the hippocampus

    Directory of Open Access Journals (Sweden)

    Sidarta Ribeiro

    2007-10-01

    Full Text Available Episodic and spatial memories engage the hippocampus during acquisition but migrate to the cerebral cortex over time. We have recently proposed that the interplay between slow-wave (SWS and rapid eye movement (REM sleep propagates recent synaptic changes from the hippocampus to the cortex. To test this theory, we jointly assessed extracellular neuronal activity, local field potentials (LFP, and expression levels of plasticity-related immediate-early genes (IEG arc and zif-268 in rats exposed to novel spatio-tactile experience. Post-experience firing rate increases were strongest in SWS and lasted much longer in the cortex (hours than in the hippocampus (minutes. During REM sleep, firing rates showed strong temporal dependence across brain areas: cortical activation during experience predicted hippocampal activity in the first post-experience hour, while hippocampal activation during experience predicted cortical activity in the third post-experience hour. Four hours after experience, IEG expression was specifically upregulated during REM sleep in the cortex, but not in the hippocampus. Arc gene expression in the cortex was proportional to LFP amplitude in the spindle-range (10-14 Hz but not to firing rates, as expected from signals more related to dendritic input than to somatic output. The results indicate that hippocampo-cortical activation during waking is followed by multiple waves of cortical plasticity as full sleep cycles recur. The absence of equivalent changes in the hippocampus may explain its mnemonic disengagement over time.

  7. Mesial temporal lobe epilepsy lateralization using SPHARM-based features of hippocampus and SVM

    Science.gov (United States)

    Esmaeilzadeh, Mohammad; Soltanian-Zadeh, Hamid; Jafari-Khouzani, Kourosh

    2012-02-01

    This paper improves the Lateralization (identification of the epileptogenic hippocampus) accuracy in Mesial Temporal Lobe Epilepsy (mTLE). In patients with this kind of epilepsy, usually one of the brain's hippocampi is the focus of the epileptic seizures, and resection of the seizure focus is the ultimate treatment to control or reduce the seizures. Moreover, the epileptogenic hippocampus is prone to shrinkage and deformation; therefore, shape analysis of the hippocampus is advantageous in the preoperative assessment for the Lateralization. The method utilized for shape analysis is the Spherical Harmonics (SPHARM). In this method, the shape of interest is decomposed using a set of bases functions and the obtained coefficients of expansion are the features describing the shape. To perform shape comparison and analysis, some pre- and post-processing steps such as "alignment of different subjects' hippocampi" and the "reduction of feature-space dimension" are required. To this end, first order ellipsoid is used for alignment. For dimension reduction, we propose to keep only the SPHARM coefficients with maximum conformity to the hippocampus shape. Then, using these coefficients of normal and epileptic subjects along with 3D invariants, specific lateralization indices are proposed. Consequently, the 1536 SPHARM coefficients of each subject are summarized into 3 indices, where for each index the negative (positive) value shows that the left (right) hippocampus is deformed (diseased). Employing these indices, the best achieved lateralization accuracy for clustering and classification algorithms are 85% and 92%, respectively. This is a significant improvement compared to the conventional volumetric method.

  8. Effect of pregabalin on apoptotic regulatory genes in hippocampus of rats with chronic temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    ZHANG Yi-dan

    2012-04-01

    Full Text Available Objective To observe the effect of pregabalin on the expression of Bcl-2 and Bax in hippocampus of chronic epileptic rats induced by pilocarpine, to explore the anti-epileptic pharmacology mechanism of pregabalin, and its anti-apoptotic effect on hippocampal neurons of rats. Methods The model of chronic temporal lobe epileptic rats induced by lithium-pilocarpine was established, then the rats in pregabalin treatment group received intraperitoneal injection of pregabalin (40 mg/kg once daily for three weeks. The expression of Bcl-2 and Bax in hippocampus of all rats was detected by immunohistochemical technique and Western blotting. Results Compared with normal saline group rats, the expression of Bcl-2 and Bax in hippocampus of rats with chronic temporal lobe epilepsy was significantly increased (P = 0.000, for all. Pregabalin can down-regulate the expression of Bax and up-regulate the expression of Bcl-2 in hippocampus of rats compared to model group rats (P = 0.000, for all. Conclusion Pregabalin may have the effects of inhibiting cell apoptosis and protecting neurons through lowing Bax level and increasing Bcl-2 level in hippocampus of chronic temporal lobe epileptic rats.

  9. Expression of Toll-like receptor 4 in hippocampus of rat model with temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    PAN Li-ping

    2013-12-01

    Full Text Available Objective To investigate the expression of Toll-like receptor 4 (TLR4 protein in hippocampus of rat model with temporal lobe epilepsy after status epilepticus (SE and explore its function in the pathogenesis of temporal lobe epilepsy. Methods Rat model with temporal lobe epilepsy was induced by lithium chloride (LiCl-pilocarpine. Total protein was extracted from hippocampus and rat brain slices were obtained at different time points (0, 1, 6, 12, 24, 48 h and 7, 10, 30, 50 d after SE. Western blotting and immunohistochemical staining were used for detection of the expression of TLR4 in the hippocampus. Results The results of Western blotting showed the TLR4 protein expression at 0, 1, 6, 12, 24, 48 h and 7, 10, 30 d after SE was higher than that in the control group (P 0.05. Conclusion TLR4 protein was mainly expressed in cytoplasm of pyramidal cells in CA3 area of hippocampus. TLR4 protein expression in the hippocampus was increased in varying degrees at different observation time points after SE, indicating that TLR4 may play an important role in the development of epilepsy.

  10. The 5-HT(4) receptor levels in hippocampus correlates inversely with memory test performance in humans

    DEFF Research Database (Denmark)

    Haahr, Mette Ewers; Fisher, Patrick; Holst, Klaus Kähler

    2013-01-01

    The cerebral serotonin (5-HT) system is involved in cognitive functions such as memory and learning and animal studies have repeatedly shown that stimulation of the 5-HT type 4 receptor (5-HT(4) R) facilitates memory and learning and further that the 5-HT(4) R modulates cellular memory processes...... in hippocampus. However, any associations between memory functions and the expression of the 5-HT(4) R in the human hippocampus have not been investigated. Using positron emission tomography with the tracer [(11) C]SB207145 and Reys Auditory Verbal Learning Test we aimed to examine the individual variation...... of the 5-HT4R binding in hippocampus in relation to memory acquisition and consolidation in healthy young volunteers. We found significant, negative associations between the immediate recall scores and left and right hippocampal BP(ND) , (p = 0.009 and p = 0.010 respectively) and between the right...

  11. Memory-Guided Attention: Independent Contributions of the Hippocampus and Striatum.

    Science.gov (United States)

    Goldfarb, Elizabeth V; Chun, Marvin M; Phelps, Elizabeth A

    2016-01-20

    Memory can strongly influence how attention is deployed in future encounters. Though memory dependent on the medial temporal lobes has been shown to drive attention, how other memory systems could concurrently and comparably enhance attention is less clear. Here, we demonstrate that both reinforcement learning and context memory facilitate attention in a visual search task. Using functional magnetic resonance imaging, we dissociate the mechanisms by which these memories guide attention: trial by trial, the hippocampus (not the striatum) predicted attention benefits from context memory, while the striatum (not the hippocampus) predicted facilitation from rewarded stimulus-response associations. Responses in these regions were also distinctly correlated with individual differences in each type of memory-guided attention. This study provides novel evidence for the role of the striatum in guiding attention, dissociable from hippocampus-dependent context memory.

  12. A high-fat diet decreases GABA concentration in the frontal cortex and hippocampus of rats

    Directory of Open Access Journals (Sweden)

    Cuauhtemoc Sandoval-Salazar

    Full Text Available BACKGROUND: It has been proposed that the γ-aminobutyric acid (GABA plays a key role in the regulation of food intake and body weight by controlling the excitability, plasticity and the synchronization of neuronal activity in the frontal cortex (FC. It has been also proposed that the high-fat diet (HFD could disturb the metabolism of glutamate and consequently the GABA levels, but the mechanism is not yet clearly understood. Therefore, the aim of this study was to investigate the effect of a HFD on the GABA levels in the FC and hippocampus of rats RESULTS: The HFD significantly increased weight gain and blood glucose levels, whereas decreased the GABA levels in the FC and hippocampus compared with standard diet-fed rats CONCLUSIONS: HFD decreases GABA levels in the FC and hippocampus of rat, which likely disrupts the GABAergic inhibitory processes, underlying feeding behavior.

  13. A high-fat diet decreases GABA concentration in the frontal cortex and hippocampus of rats.

    Science.gov (United States)

    Sandoval-Salazar, Cuauhtemoc; Ramírez-Emiliano, Joel; Trejo-Bahena, Aurora; Oviedo-Solís, Cecilia I; Solís-Ortiz, Martha Silvia

    2016-02-29

    It has been proposed that the γ-aminobutyric acid (GABA) plays a key role in the regulation of food intake and body weight by controlling the excitability, plasticity and the synchronization of neuronal activity in the frontal cortex (FC). It has been also proposed that the high-fat diet (HFD) could disturb the metabolism of glutamate and consequently the GABA levels, but the mechanism is not yet clearly understood. Therefore, the aim of this study was to investigate the effect of a HFD on the GABA levels in the FC and hippocampus of rats. The HFD significantly increased weight gain and blood glucose levels, whereas decreased the GABA levels in the FC and hippocampus compared with standard diet-fed rats. HFD decreases GABA levels in the FC and hippocampus of rat, which likely disrupts the GABAergic inhibitory processes, underlying feeding behavior.

  14. Synaptic plasticity, memory and the hippocampus: a neural network approach to causality.

    Science.gov (United States)

    Neves, Guilherme; Cooke, Sam F; Bliss, Tim V P

    2008-01-01

    Two facts about the hippocampus have been common currency among neuroscientists for several decades. First, lesions of the hippocampus in humans prevent the acquisition of new episodic memories; second, activity-dependent synaptic plasticity is a prominent feature of hippocampal synapses. Given this background, the hypothesis that hippocampus-dependent memory is mediated, at least in part, by hippocampal synaptic plasticity has seemed as cogent in theory as it has been difficult to prove in practice. Here we argue that the recent development of transgenic molecular devices will encourage a shift from mechanistic investigations of synaptic plasticity in single neurons towards an analysis of how networks of neurons encode and represent memory, and we suggest ways in which this might be achieved. In the process, the hypothesis that synaptic plasticity is necessary and sufficient for information storage in the brain may finally be validated.

  15. Physical Exercise Habits Correlate with Gray Matter Volume of the Hippocampus in Healthy Adult Humans

    Science.gov (United States)

    Killgore, William D. S.; Olson, Elizabeth A.; Weber, Mareen

    2013-12-01

    Physical activity facilitates neurogenesis of dentate cells in the rodent hippocampus, a brain region critical for memory formation and spatial representation. Recent findings in humans also suggest that aerobic exercise can lead to increased hippocampal volume and enhanced cognitive functioning in children and elderly adults. However, the association between physical activity and hippocampal volume during the period from early adulthood through middle age has not been effectively explored. Here, we correlated the number of minutes of self-reported exercise per week with gray matter volume of the hippocampus using voxel-based morphometry (VBM) in 61 healthy adults ranging from 18 to 45 years of age. After controlling for age, gender, and total brain volume, total minutes of weekly exercise correlated significantly with volume of the right hippocampus. Findings highlight the relationship between regular physical exercise and brain structure during early to middle adulthood.

  16. Differential activation of amygdala, dorsal and ventral hippocampus following an exposure to a reminder ofunderwater trauma

    Directory of Open Access Journals (Sweden)

    Gilad eRitov

    2014-01-01

    Full Text Available Recollection of emotional memories is attributed in part to the activation of the amygdala and the hippocampus. Recent hypothesis suggest a pivotal role for the ventral hippocampus in traumatic stress processing and emotional memory retrieval. Persistent re-experiencing and intrusive recollections are core symptoms in acute and posttraumatic stress disorders (ASD; PTSD. Such intrusive recollections are often triggered by reminders associated with the trauma.We examined the impact of exposure to a trauma reminder (under water trauma on the activation of the basolateral amygdala (BLA, dorsal and ventral hippocampus. Rats were exposed to underwater trauma and 24 hours later were re-exposed to the context of the trauma. Phosphorylation of the extracellular signal-regulated kinase (ERK was used as a marker for level of activation of these regions. Significant increase in ERK activation was found in the ventral hippocampus and BLA. Such pattern of activation was not found in animals exposed only to the trauma or in animals exposed only to the trauma reminder. Additionally, the dissociative pattern of activation of the ventral hippocampus sub-regions positively correlated with the activation of the BLA.Our findings suggest a specific pattern of neural activation during recollection of a trauma reminder, with a unique contribution of the ventral hippocampus. Measured 24 hrs after the exposure to the traumatic experience, the current findings relate to relatively early stages of traumatic memory consolidation. Understanding the neural mechanisms underlying these initial stages may contribute to developing intervention strategies that could reduce the risk of eventually developing PTSD.

  17. Hippocampus duality: Memory and novelty detection are subserved by distinct mechanisms.

    Science.gov (United States)

    Barbeau, Emmanuel J; Chauvel, Patrick; Moulin, Christopher J A; Regis, Jean; Liégeois-Chauvel, Catherine

    2017-04-01

    The hippocampus plays a pivotal role both in novelty detection and in long-term memory. The physiological mechanisms underlying these behaviors have yet to be understood in humans. We recorded intracerebral evoked potentials within the hippocampus of epileptic patients (n = 10) during both memory and novelty detection tasks (targets in oddball tasks). We found that memory and detection tasks elicited late local field potentials in the hippocampus during the same period, but of opposite polarity (negative during novelty detection tasks, positive during memory tasks, ∼260-600 ms poststimulus onset, P < 0.05). Critically, these potentials had maximal amplitude on the same contact in the hippocampus for each patient. This pattern did not depend on the task as different types of memory and novelty detection tasks were used. It did not depend on the novelty of the stimulus or the difficulty of the task either. Two different hypotheses are discussed to account for this result: it is either due to the activation of CA1 pyramidal neurons by two different pathways such as the monosynaptic and trisynaptic entorhinal-hippocampus pathways, or to the activation of different neuronal populations, that is, differing either functionally (e.g., novelty/familiarity neurons) or located in different regions of the hippocampus (e.g., CA1/subiculum). In either case, these activities may integrate the activity of two distinct large-scale networks implementing externally or internally oriented, mutually exclusive, brain states. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Dosimetric analysis of the alopecia preventing effect of hippocampus sparing whole brain radiation therapy

    International Nuclear Information System (INIS)

    Mahadevan, Anand; Sampson, Carrie; LaRosa, Salvatore; Floyd, Scott R.; Wong, Eric T.; Uhlmann, Erik J.; Sengupta, Soma; Kasper, Ekkehard M.

    2015-01-01

    Whole brain radiation therapy (WBRT) is widely used for the treatment of brain metastases. Cognitive decline and alopecia are recognized adverse effects of WBRT. Recently hippocampus sparing whole brain radiation therapy (HS-WBRT) has been shown to reduce the incidence of memory loss. In this study, we found that multi-field intensity modulated radiation therapy (IMRT), with strict constraints to the brain parenchyma and to the hippocampus, reduces follicular scalp dose and prevents alopecia. Suitable patients befitting the inclusion criteria of the RTOG 0933 trial received Hippocampus sparing whole brain radiation. On follow up, they were noticed to have full scalp hair preservation. 5 mm thickness of follicle bearing scalp in the radiation field was outlined in the planning CT scans. Conventional opposed lateral WBRT radiation fields were applied to these patient-specific image sets and planned with the same nominal dose of 30 Gy in 10 fractions. The mean and maximum dose to follicle bearing skin and Dose Volume Histogram (DVH) data were analyzed for conventional and HS-WBRT. Paired t-test was used to compare the means. All six patients had fully preserved scalp hair and remained clinically cognitively intact 1–3 months after HS-WBRT. Compared to conventional WBRT, in addition to the intended sparing of the Hippocampus, HS-WBRT delivered significantly lower mean dose (22.42 cGy vs. 16.33 cGy, p < 0.0001), V 24 (9 cc vs. 44 cc, p < 0.0000) and V 30 (9 cc vs. 0.096 cc, p = 0.0106) to follicle hair bearing scalp and prevented alopecia. There were no recurrences in the Hippocampus area. HS-WBRT, with an 11-field set up as described, while attempting to conserve hippocampus radiation and maintain radiation dose to brain inadvertently spares follicle-bearing scalp and prevents alopecia

  19. Differential Age-Related Changes in Structural Covariance Networks of Human Anterior and Posterior Hippocampus

    Directory of Open Access Journals (Sweden)

    Xinwei Li

    2018-05-01

    Full Text Available The hippocampus plays an important role in memory function relying on information interaction between distributed brain areas. The hippocampus can be divided into the anterior and posterior sections with different structure and function along its long axis. The aim of this study is to investigate the effects of normal aging on the structural covariance of the anterior hippocampus (aHPC and the posterior hippocampus (pHPC. In this study, 240 healthy subjects aged 18–89 years were selected and subdivided into young (18–23 years, middle-aged (30–58 years, and older (61–89 years groups. The aHPC and pHPC was divided based on the location of uncal apex in the MNI space. Then, the structural covariance networks were constructed by examining their covariance in gray matter volumes with other brain regions. Finally, the influence of age on the structural covariance of these hippocampal sections was explored. We found that the aHPC and pHPC had different structural covariance patterns, but both of them were associated with the medial temporal lobe and insula. Moreover, both increased and decreased covariances were found with the aHPC but only increased covariance was found with the pHPC with age (p < 0.05, family-wise error corrected. These decreased connections occurred within the default mode network, while the increased connectivity mainly occurred in other memory systems that differ from the hippocampus. This study reveals different age-related influence on the structural networks of the aHPC and pHPC, providing an essential insight into the mechanisms of the hippocampus in normal aging.

  20. The muscarinic stimulation of phospholipid labeling in hippocampus is independent of its cholinergic input

    International Nuclear Information System (INIS)

    Fisher, S.K.; Boast, C.A.; Agranoff, B.W.

    1980-01-01

    The authors have examined the role of cholinergic innervation on the acetylcholine (ACh)-induced 'phospholipid labeling effect' (PLE) in synaptosomes derived from the hippocampus. The hippocampus supports a robust PLE and its sole cholinergic input from the septal nuclei can be readily disrupted by the placement of lesions in the fornix. The lesion is expected to cause degeneration of cholinergic presynaptic fibers, but should have little effect on the integrity of postsynaptic structures, and thus provide a means of further localizing the synaptosomal PLE. (Auth.)

  1. Abstract memory representations in the ventromedial prefrontal cortex and hippocampus support concept generalization.

    Science.gov (United States)

    Bowman, Caitlin R; Zeithamova, Dagmar

    2018-02-07

    Memory function involves both the ability to remember details of individual experiences and the ability to link information across events to create new knowledge. Prior research has identified the ventromedial prefrontal cortex (VMPFC) and the hippocampus as important for integrating across events in service of generalization in episodic memory. The degree to which these memory integration mechanisms contribute to other forms of generalization, such as concept learning, is unclear. The present study used a concept-learning task in humans (both sexes) coupled with model-based fMRI to test whether VMPFC and hippocampus contribute to concept generalization, and whether they do so by maintaining specific category exemplars or abstract category representations. Two formal categorization models were fit to individual subject data: a prototype model that posits abstract category representations and an exemplar model that posits category representations based on individual category members. Latent variables from each of these models were entered into neuroimaging analyses to determine whether VMPFC and the hippocampus track prototype or exemplar information during concept generalization. Behavioral model fits indicated that almost three quarters of the subjects relied on prototype information when making judgments about new category members. Paralleling prototype dominance in behavior, correlates of the prototype model were identified in VMPFC and the anterior hippocampus with no significant exemplar correlates. These results indicate that the VMPFC and portions of the hippocampus play a broad role in memory generalization and that they do so by representing abstract information integrated from multiple events. SIGNIFICANCE STATEMENT Whether people represent concepts as a set of individual category members or by deriving generalized concept representations abstracted across exemplars has been debated. In episodic memory, generalized memory representations have been shown

  2. Manual morphometry of hippocampus and amygdala in adults with attention-deficit hyperactivity disorder.

    Science.gov (United States)

    Nickel, Kathrin; Tebartz van Elst, Ludger; Perlov, Evgeniy; Jitten-Schachenmeier, Renate; Beier, Daniel; Endres, Dominique; Goll, Peter; Philipsen, Alexandra; Maier, Simon

    2017-09-30

    Previous studies have pointed to the involvement of limbic structures in the genesis of attention deficit hyperactivity disorder (ADHD). The present researchers manually segmented magnetic resonance images of 30 individuals with ADHD and 30 individually matched controls, focusing on amygdala and hippocampus volumes. Neither hippocampus nor amygdala volume differed significantly between individuals with and without ADHD. However, ADHD patients with higher hyperactivity scores had significantly smaller left amygdala volumes. This finding suggests that limbic alterations are significant in hyperactive symptoms in the pathophysiology of ADHD. Copyright © 2017. Published by Elsevier B.V.

  3. Asymmetry of Hippocampus and Amygdala Defect in Subjective Cognitive Decline Among the Community Dwelling Chinese

    Directory of Open Access Journals (Sweden)

    Ling Yue

    2018-06-01

    Full Text Available Background: Subjective cognitive decline (SCD may be the first clinical sign of Alzheimer's disease (AD. SCD individuals with normal cognition may already have significant medial temporal lobe atrophy. However, few studies have been devoted to exploring the alteration of left-right asymmetry with hippocampus and amygdala in SCD. The aim of this study was to compare SCD individuals with amnestic mild cognitive impairment (MCI patients and the normal population for volume and asymmetry of hippocampus, amygdala and temporal horn, and to assess their relationship with cognitive function in elderly population living in China.Methods: 111 SCD, 30 MCI, and 67 healthy controls (HC underwent a standard T1-weighted MRI, from which the volumes of the hippocampus and amygdala were calculated and compared. Then we evaluated the pattern and extent of asymmetry in hippocampus and amygdala of these samples. Furthermore, we also investigated the relationship between the altered brain regions and cognitive function.Results: Among the three groups, SCD showed more depressive symptoms (p < 0.001 and higher percentage of heart disease (16.4% vs. 35.1%, p = 0.007 than controls. In terms of brain data, significant differences were found in the volume and asymmetry of both hippocampus and amygdala among the three groups (P < 0.05. In logistic analysis controlled by age, gender, education level, depression symptoms, anxiety symptom, somatic disease and lifestyle in terms of smoking, both SCD and MCI individuals showed significant decreased right hippocampal and amygdala volume than controls. For asymmetry pattern, a ladder-shaped difference of left-larger-than-right asymmetry was found in amygdala with MCI>SCD>HC, and an opposite asymmetry of left-less-than-right pattern was found with HC>SCD>MCI in hippocampus. Furthermore, correlation was shown between the volume of right hippocampus and right amygdala with MMSE and MoCA in SCD group.Conclusion: Our results supported

  4. Adeno-Associated Viral Vector-Induced Overexpression of Neuropeptide Y Y2 Receptors in the Hippocampus Suppresses Seizures

    Science.gov (United States)

    Woldbye, David P. D.; Angehagen, Mikael; Gotzsche, Casper R.; Elbrond-Bek, Heidi; Sorensen, Andreas T.; Christiansen, Soren H.; Olesen, Mikkel V.; Nikitidou, Litsa; Hansen, Thomas v. O.; Kanter-Schlifke, Irene; Kokaia, Merab

    2010-01-01

    Gene therapy using recombinant adeno-associated viral vectors overexpressing neuropeptide Y in the hippocampus exerts seizure-suppressant effects in rodent epilepsy models and is currently considered for clinical application in patients with intractable mesial temporal lobe epilepsy. Seizure suppression by neuropeptide Y in the hippocampus is…

  5. Common proteomic changes in the hippocampus in schizophrenia and bipolar disorder and particular evidence for involvement of cornu ammonis regions 2 and 3.

    LENUS (Irish Health Repository)

    2011-05-01

    The hippocampus is strongly implicated in schizophrenia and, to a lesser degree, bipolar disorder. Proteomic investigations of the different regions of the hippocampus may help us to clarify the basis and the disease specificity of the changes.

  6. Hippocampus and amygdala volumes in parents of children with autistic disorder.

    Science.gov (United States)

    Rojas, Donald C; Smith, J Allegra; Benkers, Tara L; Camou, Suzanne L; Reite, Martin L; Rogers, Sally J

    2004-11-01

    Structural and functional abnormalities in the medial temporal lobe, particularly the hippocampus and amygdala, have been described in people with autism. The authors hypothesized that parents of children with a diagnosis of autistic disorder would show similar changes in these structures. Magnetic resonance imaging scans were performed in 17 biological parents of children with a diagnosis of DSM-IV autistic disorder. The scans were compared with scans from 15 adults with autistic disorder and 17 age-matched comparison subjects with no personal or familial history of autism. The volumes of the hippocampus, amygdala, and total brain were measured in all participants. The volume of the left hippocampus was larger in both the parents of children with autistic disorder and the adults with autistic disorder, relative to the comparison subjects. The hippocampus was significantly larger in the adults with autistic disorder than in the parents of children with autistic disorder. The left amygdala was smaller in the adults with autistic disorder, relative to the other two groups. No differences in total brain volume were observed between the three groups. The finding of larger hippocampal volume in autism is suggestive of abnormal early neurodevelopmental processes but is partly consistent with only one prior study and contradicts the findings of several others. The finding of larger hippocampal volume for the parental group suggests a potential genetic basis for hippocampal abnormalities in autism.

  7. Similar effects of substance P on learning and memory function between hippocampus and striatal marginal division

    Science.gov (United States)

    Yu, Yan; Zeng, Changchun; Shu, Siyun; Liu, Xuemei; Li, Chuhua

    2014-01-01

    Substance P is an endogenous neurokinin that is present in the central and peripheral nervous systems. The neuropeptide substance P and its high-affinity receptor neurokinin 1 receptor are known to play an important role in the central nervous system in inflammation, blood pressure, motor behavior and anxiety. The effects of substance P in the hippocampus and the marginal division of the striatum on memory remain poorly understood. Compared with the hippocampus as a control, immunofluorescence showed high expression of the substance P receptor, neurokinin 1, in the marginal division of the striatum of normal rats. Unilateral or bilateral injection of an antisense oligonucleotide against neurokinin 1 receptor mRNA in the rat hippocampus or marginal division of the striatum effectively reduced neurokinin 1 receptor expression. Independent of injection site, rats that received this antisense oligonucleotide showed obviously increased footshock times in a Y-maze test. These results indicate that the marginal division of the striatum plays a similar function in learning and memory to the hippocampus, which is a valuable addition to our mechanistic understanding of the learning and memory functions of the marginal division of the striatum. PMID:25206901

  8. Association between Mastication, the Hippocampus, and the HPA Axis: A Comprehensive Review.

    Science.gov (United States)

    Azuma, Kagaku; Zhou, Qian; Niwa, Masami; Kubo, Kin-Ya

    2017-08-03

    Mastication is mainly involved in food intake and nutrient digestion with the aid of teeth. Mastication is also important for preserving and promoting general health, including hippocampus-dependent cognition. Both animal and human studies indicate that mastication influences hippocampal functions through the end product of the hypothalamic-pituitary-adrenal (HPA) axis, glucocorticoid (GC). Epidemiologic studies suggest that masticatory dysfunction in aged individuals, such as that resulting from tooth loss and periodontitis, acting as a source of chronic stress, activates the HPA axis, leading to increases in circulating GCs and eventually inducing various physical and psychological diseases, such as cognitive impairment, cardiovascular disorders, and osteoporosis. Recent studies demonstrated that masticatory stimulation or chewing during stressful conditions suppresses the hyperactivity of the HPA axis via GCs and GC receptors within the hippocampus, and ameliorates chronic stress-induced hippocampus-dependent cognitive deficits. Here, we provide a comprehensive overview of current research regarding the association between mastication, the hippocampus, and HPA axis activity. We also discuss several potential molecular mechanisms involved in the interactions between mastication, hippocampal function, and HPA axis activity.

  9. The influence of interleukin-1beta on gamma-glutamyl transpeptidase activity in rat hippocampus

    Czech Academy of Sciences Publication Activity Database

    Kaiser, M.; Mareš, Vladislav; Šťastný, František; Bubeníková-Valešová, V.; Lisá, Věra; Suchomel, P.; Balcar, V. J.

    2006-01-01

    Roč. 55, č. 4 (2006), s. 461-465 ISSN 0862-8408 R&D Projects: GA MZd(CZ) NF7626 Institutional research plan: CEZ:AV0Z50110509 Keywords : interleukin-1beta * gamma- glutamyltranspeptidase * hippocampus Subject RIV: ED - Physiology Impact factor: 2.093, year: 2006

  10. From rapid place learning to behavioral performance: a key role for the intermediate hippocampus.

    Directory of Open Access Journals (Sweden)

    Tobias Bast

    2009-04-01

    Full Text Available Rapid place encoding by hippocampal neurons, as reflected by place-related firing, has been intensely studied, whereas the substrates that translate hippocampal place codes into behavior have received little attention. A key point relevant to this translation is that hippocampal organization is characterized by functional-anatomical gradients along the septotemporal axis: Whereas the ability of hippocampal neurons to encode accurate place information declines from the septal to temporal end, hippocampal connectivity to prefrontal and subcortical sites that might relate such place information to behavioral-control processes shows an opposite gradient. We examined in rats the impact of selective lesions to relevant parts of the hippocampus on behavioral tests requiring place learning (watermaze procedures and on in vivo electrophysiological models of hippocampal encoding (long-term potentiation [LTP], place cells. We found that the intermediate hippocampus is necessary and largely sufficient for behavioral performance based on rapid place learning. In contrast, a residual septal pole of the hippocampus, although displaying intact electrophysiological indices of rapid information encoding (LTP, precise place-related firing, and rapid remapping, failed to sustain watermaze performance based on rapid place learning. These data highlight the important distinction between hippocampal encoding and the behavioral performance based on such encoding, and suggest that the intermediate hippocampus, where substrates of rapid accurate place encoding converge with links to behavioral control, is critical to translate rapid (one-trial place learning into navigational performance.

  11. A gene-environment study of cytoglobin in the human and rat hippocampus

    DEFF Research Database (Denmark)

    Hundahl, Christian Ansgar; Elfving, Betina; Müller, Heidi Kaastrup

    2013-01-01

    Cytoglobin (Cygb) was discovered a decade ago as the fourth vertebrate heme-globin. The function of Cygb is still unknown, but accumulating evidence from in vitro studies point to a putative role in scavenging of reactive oxygen species and nitric oxide metabolism and in vivo studies have shown C......NOS) in the rat hippocampus; 3) The effect of chronic restraint stress (CRS) on Cygb and nNOS expression.......Cytoglobin (Cygb) was discovered a decade ago as the fourth vertebrate heme-globin. The function of Cygb is still unknown, but accumulating evidence from in vitro studies point to a putative role in scavenging of reactive oxygen species and nitric oxide metabolism and in vivo studies have shown...... Cygb to be up regulated by hypoxic stress. This study addresses three main questions related to Cygb expression in the hippocampus: 1) Is the rat hippocampus a valid neuroanatomical model for the human hippocampus; 2) What is the degree of co-expression of Cygb and neuronal nitric oxide synthase (n...

  12. Glutamine synthetase activity and glutamate uptake in hippocampus and frontal cortex in portal hypertensive rats

    Science.gov (United States)

    Acosta, Gabriela Beatriz; Fernández, María Alejandra; Roselló, Diego Martín; Tomaro, María Luján; Balestrasse, Karina; Lemberg, Abraham

    2009-01-01

    AIM: To study glutamine synthetase (GS) activity and glutamate uptake in the hippocampus and frontal cortex (FC) from rats with prehepatic portal vein hypertension. METHODS: Male Wistar rats were divided into sham-operated group and a portal hypertension (PH) group with a regulated stricture of the portal vein. Animals were sacrificed by decapitation 14 d after portal vein stricture. GS activity was determined in the hippocampus and FC. Specific uptake of radiolabeled L-glutamate was studied using synaptosome-enriched fractions that were freshly prepared from both brain areas. RESULTS: We observed that the activity of GS increased in the hippocampus of PH rats, as compared to control animals, and decreased in the FC. A significant decrease in glutamate uptake was found in both brain areas, and was more marked in the hippocampus. The decrease in glutamate uptake might have been caused by a deficient transport function, significantly and persistent increase in this excitatory neurotransmitter activity. CONCLUSION: The presence of moderate ammonia blood levels may add to the toxicity of excitotoxic glutamate in the brain, which causes alterations in brain function. Portal vein stricture that causes portal hypertension modifies the normal function in some brain regions. PMID:19533812

  13. Evidence that stress activates glial lactate formation in vivo assessed with rat hippocampus lactography

    NARCIS (Netherlands)

    Elekes, O; Venema, K; Postema, F; Dringen, R; Hamprecht, B; Korf, J

    1996-01-01

    Extracellular lactate of the rat hippocampus is inter alia increased by immobilization stress. The origin of lactate is, however, not well established, so it is not known whether it is mainly derived form neurons or glial cells. Dialysates were collected shortly (1 or 2 days) or with a delay (14 or

  14. Tuning synaptic transmission in the hippocampus by stress: The CRH system

    Directory of Open Access Journals (Sweden)

    Yuncai eChen

    2012-04-01

    Full Text Available To enhance survival, an organism needs to remember--and learn from--threatening or stressful events. This fact necessitates the presence of mechanisms by which stress can influence synaptic transmission in brain regions, such as hippocampus, that subserve learning and memory. A major focus of this series of monographs is on the role and actions of adrenal-derived hormones, corticosteroids, and of brain-derived neurotransmitters, on synaptic function in the stressed hippocampus. Here we focus on the contribution of hippocampus-intrinsic, stress-activated CRH-CRH receptor signaling to the function and structure of hippocampal synapses. CRH is expressed in interneurons of adult hippocampus, and is released from axon terminals during stress. The peptide exerts time- and dose-dependent effects on learning and memory via modulation of synaptic function and plasticity. Whereas physiological levels of CRH, acting over seconds to minutes, augment memory processes, exposure to presumed severe-stress levels of the peptide results in spine retraction and loss of synapses over more protracted time-frames. Loss of dendritic spines (and hence of synapses takes place through actin cytoskeleton collapse downstream of CRHR1 receptors that reside within excitatory synapses on spine heads. Chronic exposure to stress levels of CRH may promote dying-back (atrophy of spine-carrying dendrites. Thus, the acute effects of CRH may contribute to stress-induced adaptive mechanisms, whereas chronic or excessive exposure to the peptide may promote learning problems and premature cognitive decline.

  15. REDUCTION OF ADENOSINE-A1-RECEPTORS IN THE PERFORANT PATHWAY TERMINAL ZONE IN ALZHEIMER HIPPOCAMPUS

    NARCIS (Netherlands)

    JAARSMA, D; SEBENS, JB; KORF, J

    1991-01-01

    The cells of origin of the perforant pathway are destroyed in Alzheimer's disease (AD). In rat the adenosine A1-receptors are specifically localized on the perforant path terminals in the molecular layer of the dentate gyrus. In the present study the density of A1-receptors in the hippocampus of

  16. Decreased BDNF levels in amygdala and hippocampus after intracerebroventricular administration of ouabain

    Directory of Open Access Journals (Sweden)

    Luciano K. Jornada

    2012-01-01

    Full Text Available OBJECTIVE: The present study aims to investigate the effects of ouabain intracerebroventricular injection on BDNF levels in the amygdala and hippocampus of Wistar rats. METHODS: Animals received a single intracerebroventricular injection of ouabain (10-3 and 10-2 M or artificial cerebrospinal fluid and immediately, 1h, 24h, or seven days after injection, BDNF levels were measured in the rat's amygdala and hippocampus by sandwich-ELISA (n = 8 animals per group. RESULTS: When evaluated immediately, 3h, or 24h after injection, ouabain in doses of 10-2 and 10-3 M does not alter BDNF levels in the amygdala and hippocampus. However, when evaluated seven days after injection, ouabain in 10-2 and 10-3 M, showed a significant reduction in BDNF levels in both brain regions evaluated. DISCUSSION: In conclusion, we propose that the ouabain decreased BDNF levels in the hippocampus and amygdala when assessed seven days after administration, supporting the Na/K ATPase hypothesis for bipolar illness.

  17. Phencyclidine administration during neurodevelopment alters network activity in prefrontal cortex and hippocampus in adult rats.

    Science.gov (United States)

    Kjaerby, Celia; Hovelsø, Nanna; Dalby, Nils Ole; Sotty, Florence

    2017-08-01

    Symptoms of schizophrenia have been linked to insults during neurodevelopment such as NMDA receptor (NMDAR) antagonist exposure. In animal models, this leads to schizophrenia-like behavioral symptoms as well as molecular and functional changes within hippocampal and prefrontal regions. The aim of this study was to determine how administration of the NMDAR antagonist phencyclidine (PCP) during neurodevelopment affects functional network activity within the hippocampus and medial prefrontal cortex (mPFC). We recorded field potentials in vivo after electrical brain stem stimulation and observed a suppression of evoked theta power in ventral hippocampus, while evoked gamma power in mPFC was enhanced in rats administered with PCP neonatally. In addition, increased gamma synchrony elicited by acute administration of the NMDAR antagonist MK-801 was exaggerated in neonatal PCP animals. These data suggest that NMDAR antagonist exposure during brain development alters functional networks within hippocampus and mPFC possibly contributing to the reported behavioral symptoms of this animal model of schizophrenia. NEW & NOTEWORTHY We show that insults with a NMDA receptor antagonist during neurodevelopment lead to suppressed evoked theta oscillations in ventral hippocampus in adult rats, while evoked gamma oscillations are enhanced and hypersensitive to an acute challenge with a NMDA receptor antagonist in prefrontal cortex. These observations reveal the significance of neurodevelopmental disturbances in the evolvement of schizophrenia-like symptoms and contribute to the understanding of the functional deficits underlying aberrant behavior in this disease. Copyright © 2017 the American Physiological Society.

  18. Mitochondria morphologic changes and metabolic effects of rat hippocampus after microwave irradiation

    International Nuclear Information System (INIS)

    Zhao Li; Peng Ruiyun; Gao Yabing; Wang Shuiming; Wang Lifeng; Dong Qi; Xu Xinping; Ma Junjie

    2007-01-01

    Objective: To investigate the effect of microwave on mitochondria morphologic and metabolism of rat hippocampus. Methods: 30 male rats were exposed to microwave with the average power density of 30 mW/cm 2 . Rats were sacrificed at 6 h, 1 d, 3 d and 7 d after irradiation. Electron microscope, enzymatic activity staining and spectrophotometer were used to study ultrastructure change of hippocampus mitochondria and activity of ATPase, SDH and MAO. Mitochondrial ATP, ADP and AMP contents were measured by high performance liquid chromatography (HPLC). Results: At 6 h after microwave radiation, the sizes and shapes of hippocampus mitochondria were abnormal and the injury of mitochondria was aggravated at 1 and 3 d after radiation. The mitochondria presented swell, cavitation including disorder, shortness and decrease of crest. The activity of SDH and content of ATP were decreased at 6 h, most serious at 3 d(P<0.01), and recovered at 7 d after radiation. The activity of ATPase and MAO increased notably at 1 d and 3 d after radiation (P<0.01). Conclusions: Microwave can damage the structure and function of mitochondria in rat hippocampus, and cause the energy metabolism of enzyme disorder. (authors)

  19. Efficacy of sodium bicarbonate as anaesthetic for yellow seahorse, Hippocampus kuda (Bleeker, 1852)

    Digital Repository Service at National Institute of Oceanography (India)

    Pawar, H.B.; Ingole, B.S.; Sreepada, R.A.

    .J., Ryu, B.M., Kim, M.M., Kim, S.K., 2008. Free Radical and Reactive Oxygen Species Scavenging Activities of the Extracts from Seahorse, Hippocampus kuda, Bleeler. Biotechnol. Bioprocess Eng. 13, 705- 715. 20. Ross, L.G., Ross, B., 1999. Anaesthetic...

  20. The role of the hippocampus in flexible cognition and social behavior

    Directory of Open Access Journals (Sweden)

    Rachael D Rubin

    2014-09-01

    Full Text Available Successful behavior requires actively acquiring and representing information about the environment and people, and manipulating and using those acquired representations flexibly to optimally act in and on the world. The frontal lobes have figured prominently in most accounts of flexible or goal-directed behavior, as evidenced by often-reported behavioral inflexibility in individuals with frontal lobe dysfunction. Here, we propose that the hippocampus also plays a critical role by forming and reconstructing relational memory representations that underlie flexible cognition and social behavior. There is mounting evidence that damage to the hippocampus can produce inflexible and maladaptive behavior when such behavior places high demands on the generation, recombination, and flexible use of information. This is seen in abilities as diverse as memory, navigation, exploration, imagination, creativity, decision-making, character judgments, establishing and maintaining social bonds, empathy, social discourse, and language use. Thus, the hippocampus, together with its extensive interconnections with other neural systems, supports the flexible use of information in general. Further, we suggest that this understanding has important clinical implications. Hippocampal abnormalities can produce profound deficits in real-world situations, which typically place high demands on the flexible use of information, but are not always obvious on diagnostic tools tuned to frontal lobe function. This review documents the role of the hippocampus in supporting flexible representations and aims to expand our understanding of the dynamic networks that operate as we move through and create meaning of our world.

  1. Is the Hippocampus Necessary for Visual and Verbal Binding in Working Memory?

    Science.gov (United States)

    Baddeley, Alan; Allen, Richard; Vargha-Khadem, Faraneh

    2010-01-01

    A series of experiments test the recent claim that the hippocampus is necessary for the binding of features in working memory. Some potential limitations of studies underlying this claim are discussed, and an attempt is made to further test the hypothesis by studying a case of developmental amnesia whose extensively investigated pathology appears…

  2. The role of the hippocampus in flexible cognition and social behavior.

    Science.gov (United States)

    Rubin, Rachael D; Watson, Patrick D; Duff, Melissa C; Cohen, Neal J

    2014-01-01

    Successful behavior requires actively acquiring and representing information about the environment and people, and manipulating and using those acquired representations flexibly to optimally act in and on the world. The frontal lobes have figured prominently in most accounts of flexible or goal-directed behavior, as evidenced by often-reported behavioral inflexibility in individuals with frontal lobe dysfunction. Here, we propose that the hippocampus also plays a critical role by forming and reconstructing relational memory representations that underlie flexible cognition and social behavior. There is mounting evidence that damage to the hippocampus can produce inflexible and maladaptive behavior when such behavior places high demands on the generation, recombination, and flexible use of information. This is seen in abilities as diverse as memory, navigation, exploration, imagination, creativity, decision-making, character judgments, establishing and maintaining social bonds, empathy, social discourse, and language use. Thus, the hippocampus, together with its extensive interconnections with other neural systems, supports the flexible use of information in general. Further, we suggest that this understanding has important clinical implications. Hippocampal abnormalities can produce profound deficits in real-world situations, which typically place high demands on the flexible use of information, but are not always obvious on diagnostic tools tuned to frontal lobe function. This review documents the role of the hippocampus in supporting flexible representations and aims to expand our understanding of the dynamic networks that operate as we move through and create meaning of our world.

  3. Interaction between Thalamus and Hippocampus in Termination of Amygdala-Kindled Seizures in Mice

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2016-01-01

    Full Text Available The thalamus and hippocampus have been found both involved in the initiation, propagation, and termination of temporal lobe epilepsy. However, the interaction of these regions during seizures is not clear. The present study is to explore whether some regular patterns exist in their interaction during the termination of seizures. Multichannel in vivo recording techniques were used to record the neural activities from the cornu ammonis 1 (CA1 of hippocampus and mediodorsal thalamus (MDT in mice. The mice were kindled by electrically stimulating basolateral amygdala neurons, and Racine’s rank standard was employed to classify the stage of behavioral responses (stage 1~5. The coupling index and directionality index were used to investigate the synchronization and information flow direction between CA1 and MDT. Two main results were found in this study. (1 High levels of synchronization between the thalamus and hippocampus were observed before the termination of seizures at stage 4~5 but after the termination of seizures at stage 1~2. (2 In the end of seizures at stage 4~5, the information tended to flow from MDT to CA1. Those results indicate that the synchronization and information flow direction between the thalamus and the hippocampus may participate in the termination of seizures.

  4. Modulation of [3H]-glutamate binding by serotonin in the rat hippocampus: An autoradiographic study

    International Nuclear Information System (INIS)

    Mennini, T.; Miari, A.

    1991-01-01

    Serotonin (5-HT) added in vitro increased [ 3 H]-glutamate specific binding in the rat hippocampus, reaching statistical significance in layers rich in N-Methyl-D-Aspartate sensitive glutamate receptors. This effect was explained by a significant increase in the apparent affinity of [ 3 H]-glutamate when 5-HT is added in vitro. Two days after lesion of serotonergic afferents to the hippocampus with 5,7- Dihydroxytryptamine [ 3 H]-glutamate binding was significantly decreased in the CA3 region and stratum lacunosum moleculare of the hippocampus, this reduction being reversed by in vitro addition of 10 μM 5-HT. The decrease observed is due to a significant reduction of quisqualate-insensitive (radiatum CA3) and kainate receptors (strata oriens, radiatum, pyramidal of CA3). Five days after lesion [ 3 H]-glutamate binding increased significantly in the CA3 region of the hippocampus but was not different from sham animals in the other hippocampal layers. Two weeks after lesion [ 3 H]-glutamate binding to quisqualate-insensitive receptors was increased in all the hippocampal layers, while kainate and quisqualate-sensitive receptors were not affected. These data are consistent with the possibility that 5-HT is a direct positive modulator of glutamate receptor subtypes

  5. Lipoic acid effects on glutamate and taurine concentrations in rat hippocampus after pilocarpine-induced seizures

    Directory of Open Access Journals (Sweden)

    P S Santos

    2011-01-01

    Full Text Available Pilocarpine-induced seizures can be mediated by increases in oxidative stress and by cerebral amino acid changes. The present research suggests that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures in cellular level. The objective of the present study was to evaluate the lipoic acid (LA effects in glutamate and taurine contents in rat hippocampus after pilocarpine-induced seizures. Wistar rats were treated intraperitoneally (i.p. with 0.9% saline (Control, pilocarpine (400 mg/kg, Pilocarpine, LA (10 mg/kg, LA, and the association of LA (10 mg/kg plus pilocarpine (400 mg/kg, that was injected 30 min before of administration of LA (LA plus pilocarpine. Animals were observed during 24 h. The amino acid concentrations were measured using high-performance liquid chromatograph (HPLC. In pilocarpine group, it was observed a significant increase in glutamate content (37% and a decrease in taurine level (18% in rat hippocampus, when compared to control group. Antioxidant pretreatment significantly reduced the glutamate level (28% and augmented taurine content (32% in rat hippocampus, when compared to pilocarpine group. Our findings strongly support amino acid changes in hippocampus during seizures induced by pilocarpine, and suggest that glutamate-induced brain damage plays a crucial role in pathogenic consequences of seizures, and imply that strong protective effect could be achieved using lipoic acid through the release or decrease in metabolization rate of taurine amino acid during seizures.

  6. Decrease of extracellular taurine in the rat dorsal hippocampus after central nervous administration of vasopressin

    DEFF Research Database (Denmark)

    Brust, P; Christensen, Thomas; Diemer, Nils Henrik

    1992-01-01

    of the composition of the extracellular fluid. The concentrations of 16 amino acids were measured by HPLC in the perfusate samples. The level of taurine declined 20% in the right hippocampus during perfusion with vasopressin, whereas o-phosphoethanolamine decreased in both sides, the left 20% and the right 24...

  7. Disruption of the Perineuronal Net in the Hippocampus or Medial Prefrontal Cortex Impairs Fear Conditioning

    Science.gov (United States)

    Hylin, Michael J.; Orsi, Sara A.; Moore, Anthony N.; Dash, Pramod K.

    2013-01-01

    The perineuronal net (PNN) surrounds neurons in the central nervous system and is thought to regulate developmental plasticity. A few studies have shown an involvement of the PNN in hippocampal plasticity and memory storage in adult animals. In addition to the hippocampus, plasticity in the medial prefrontal cortex (mPFC) has been demonstrated to…

  8. Hippocampus, Perirhinal Cortex, and Complex Visual Discriminations in Rats and Humans

    Science.gov (United States)

    Hales, Jena B.; Broadbent, Nicola J.; Velu, Priya D.; Squire, Larry R.; Clark, Robert E.

    2015-01-01

    Structures in the medial temporal lobe, including the hippocampus and perirhinal cortex, are known to be essential for the formation of long-term memory. Recent animal and human studies have investigated whether perirhinal cortex might also be important for visual perception. In our study, using a simultaneous oddity discrimination task, rats with…

  9. First occurrence of the lined seahorse Hippocampus erectus in the eastern Atlantic Ocean.

    Science.gov (United States)

    Woodall, L C; Koldewey, H J; Santos, S V; Shaw, P W

    2009-10-01

    A seahorse specimen from Banco Açores (Azores Archipelago) was identified using morphological and molecular genetic data as Hippocampus erectus. This specimen represents the first record of H. erectus in the eastern Atlantic Ocean, well outside its reported range, and may provide evidence of long-distance translocation in what are assumed to be relatively sedentary fish.

  10. Changes in free and bound water in the hippocampus of patients with Alzheimer's disease

    International Nuclear Information System (INIS)

    Asano, Tetsuichi; Hanyu, Haruo

    2000-01-01

    We measured the T2 relaxation time using dual spin echo MRI, and also the magnetization transfer ratio (MTR) using gradient echo MRI, in the hippocampus of Alzheimer's disease (AD) patients, and compared these factors to those of non-Alzheimer's dementia (non-AD) patients and of control subjects. The degree of medial temporal lobe atrophy in AD patients was similar to that of non-AD patients, although atrophy was more severe in AD and non-AD patients than in the control group. MTRs in the hippocampus were significantly lower in AD patients than in non-AD patients and in the control group. No significant differences in the T2 values of the three groups were found. The change of T2 x (1-MTR/100) in the hippocampus was significantly higher in AD patients than in non-AD patients and the control group and the change of T2 x MTR/100 was significantly lower in AD patients than in non-AD patients and the control group. Significant correlations between MMSE scores and MR parameters were found in AD patients, but not in non-AD patients. These results suggest that a decrease in the MTR in the hippocampus of AD, probably due to a decrease in bound water and an increase in free water, reflects underlying pathological changes which include a loss of neurons and gliosis. (author)

  11. Localized hippocampus measures are associated with Alzheimer pathology and cognition independent of total hippocampal volume.

    NARCIS (Netherlands)

    Carmichael, O.; Xie, J.; Fletcher, E.; Singh, B.; DeCarli, C.; Olde Rikkert, M.; et al.,

    2012-01-01

    Hippocampal injury in the Alzheimer's disease (AD) pathological process is region-specific and magnetic resonance imaging (MRI)-based measures of localized hippocampus (HP) atrophy are known to detect region-specific changes associated with clinical AD, but it is unclear whether these measures

  12. Distinct morphology and current patterns of astrocytes in the rat hippocampus after global cerebral ischemia

    Czech Academy of Sciences Publication Activity Database

    Anděrová, Miroslava; Pivoňková, Helena; Benešová, Jana; Butenko, Olena; Chvátal, Alexandr

    2009-01-01

    Roč. 57, č. 13 (2009), S58-S59 ISSN 0894-1491. [European Meeting on Glia l Cells in Health and Disease /9./. 09.09.2009-12.09.2009, Paris] Institutional research plan: CEZ:AV0Z50390703 Keywords : Hippocampus * Morphology Subject RIV: FH - Neurology

  13. A terrified-sound stress induced proteomic changes in adult male rat hippocampus.

    Science.gov (United States)

    Yang, Juan; Hu, Lili; Wu, Qiuhua; Liu, Liying; Zhao, Lingyu; Zhao, Xiaoge; Song, Tusheng; Huang, Chen

    2014-04-10

    In this study, we investigated the biochemical mechanisms in the adult rat hippocampus underlying the relationship between a terrified-sound induced psychological stress and spatial learning. Adult male rats were exposed to a terrified-sound stress, and the Morris water maze (MWM) has been used to evaluate changes in spatial learning and memory. The protein expression profile of the hippocampus was examined using two-dimensional gel electrophoresis (2DE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and bioinformatics analysis. The data from the MWM tests suggested that a terrified-sound stress improved spatial learning. The proteomic analysis revealed that the expression of 52 proteins was down-regulated, while that of 35 proteins were up-regulated, in the hippocampus of the stressed rats. We identified and validated six of the most significant differentially expressed proteins that demonstrated the greatest stress-induced changes. Our study provides the first evidence that a terrified-sound stress improves spatial learning in rats, and that the enhanced spatial learning coincides with changes in protein expression in rat hippocampus. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Genome-wide detection and analysis of hippocampus core promoters using DeepCAGE

    DEFF Research Database (Denmark)

    Valen, Eivind; Pascarella, Giovanni; Chalk, Alistair

    2009-01-01

    in a given tissue. Here, we present a new method for high-throughput sequencing of 5' cDNA tags-DeepCAGE: merging the Cap Analysis of Gene Expression method with ultra-high-throughput sequence technology. We apply DeepCAGE to characterize 1.4 million sequenced TSS from mouse hippocampus and reveal a wealth...

  15. Theta-paced flickering between place-cell maps in the hippocampus

    Czech Academy of Sciences Publication Activity Database

    Ježek, Karel; Henriksen, E. J.; Treves, A.; Moser, E. I.; Moser, M.B.

    2011-01-01

    Roč. 478, č. 7368 (2011), s. 246-249 ISSN 0028-0836 R&D Projects: GA MŠk(CZ) LC554; GA MŠk(CZ) 1M0517 Institutional research plan: CEZ:AV0Z50110509 Keywords : memory * theta * hippocampus * place cells * teleportation Subject RIV: FH - Neurology Impact factor: 36.280, year: 2011

  16. Differential Effects of Cannabinoid Receptor Agonist on Social Discrimination and Contextual Fear in Amygdala and Hippocampus

    Science.gov (United States)

    Segev, Amir; Akirav, Irit

    2011-01-01

    We examined whether the cannabinoid receptor agonist WIN55,212-2 (WIN; 5 [mu]g/side) microinjected into the hippocampus or the amygdala would differentially affect memory processes in a neutral vs. an aversive task. In the aversive contextual fear task, WIN into the basolateral amygdala impaired fear acquisition/consolidation, but not retrieval.…

  17. Beyond memory, navigation, and inhibition: behavioral evidence for hippocampus-dependent cognitive coordination in the rat

    Czech Academy of Sciences Publication Activity Database

    Wesierska, M.; Dockery, Colleen; Fenton, André Antonio

    2005-01-01

    Roč. 25, č. 9 (2005), s. 2413-2419 ISSN 0270-6474 Grant - others:European Commission(XE) QLG3-CT-1999-00192 Institutional research plan: CEZ:AV0Z5011922 Keywords : cognition * hippocampus * cognitive disorganization Subject RIV: FH - Neurology Impact factor: 7.506, year: 2005

  18. Localized hippocampus measures are associated with Alzheimer pathology and cognition independent of total hippocampal volume

    NARCIS (Netherlands)

    Carmichael, Owen; Xie, Jing; Fletcher, Evan; Singh, Baljeet; Decarli, Charles; A, Saradha; Abdi, Hervé; Abdul Hadi, Normi; Abdulkadir, Ahmed; Abdullah, Afnizanfaizal; Achuthan, Anusha; Adluru, Nagesh; Aggarwal, Namita; Aghajanian, Jania; Agyemang, Alex; Ahdidan, Jamila; Ahmad, Duaa; Ahmed, Shiek; Ahmed, Fareed; Ahmed, Fayeza; Akbarifar, Roshanak; Akhondi-Asl, Alireza; Aksu, Yaman; Alcauter, Sarael; Daniel, Alexander; Alin, Aylin; Alshuft, Hamza; Alvarez-Linera, Juan; Amin-Mansour, Ali; Anderson, Dallas; Anderson, Jeff; Andorn, Anne; Ang, Amma; Angersbach, Steve; Ansarian, Reza; Appaji, Abhishek; Appannah, Arti; Arfanakis, Konstantinos; Armentrout, Steven; Arrighi, Michael; Arumughababu, S. Vethanayaki; Arunagiri, Vidhya; Ashe-McNalley, Cody; Ashford, Wes; Aurelie, Le Page; Avants, Brian; Aviv, Richard; Avula, Ramesh; Richard, Edo; Schmand, Ben

    2012-01-01

    Hippocampal injury in the Alzheimer's disease (AD) pathological process is region-specific and magnetic resonance imaging (MRI)-based measures of localized hippocampus (HP) atrophy are known to detect region-specific changes associated with clinical AD, but it is unclear whether these measures

  19. GABAergic Neurons of the Rat Dorsal Hippocampus Express Muscarinic Acetylcholine Receptors

    NARCIS (Netherlands)

    van der Zee, E.A.; Luiten, P.G.M.

    1993-01-01

    The expression of muscarinic acetylcholine receptors (mAChRs) in glutamic acid decarboxylase (GAD)-positive cells in the different strata of CA1, CA3, and the dentate gyrus (DG) of the dorsal hippocampus is examined by way of quantitative immunofluorescent double labeling employing M35, the

  20. Orthogonal wave propagation of epileptiform activity in the planar mouse hippocampus in vitro.

    Science.gov (United States)

    Kibler, Andrew B; Durand, Dominique M

    2011-09-01

    In vitro brain preparations have been used extensively to study the generation and propagation of epileptiform activity. Transverse and longitudinal slices of the rodent hippocampus have revealed various patterns of propagation. Yet intact connections between the transverse and longitudinal pathways should generate orthogonal (both transverse and longitudinal) propagation of seizures involving the entire hippocampus. This study utilizes the planar unfolded mouse hippocampus preparation to reveal simultaneous orthogonal epileptiform propagation and to test a method of arresting propagation. This study utilized an unfolded mouse hippocampus preparation. It was chosen due to its preservation of longitudinal neuronal processes, which are thought to play an important role in epileptiform hyperexcitability. 4-Aminopyridine (4-AP), microelectrodes, and voltage-sensitive dye imaging were employed to investigate tissue excitability. In 50-μm 4-AP, stimulation of the stratum radiatum induced transverse activation of CA3 cells but also induced a longitudinal wave of activity propagating along the CA3 region at a speed of 0.09 m/s. Without stimulation, a wave originated at the temporal CA3 and propagated in a temporal-septal direction could be suppressed with glutamatergic receptor antagonists. Orthogonal propagation traveled longitudinally along the CA3 pathway, secondarily invading the CA1 region at a velocity of 0.22 ± 0.024 m/s. Moreover, a local lesion restricted to the CA3 region could arrest wave propagation. These results reveal a complex two-dimensional epileptiform wave propagation pattern in the hippocampus that is generated by a combination of synaptic transmission and axonal propagation in the CA3 recurrent network. Epileptiform propagation block via a transverse selective CA3 lesion suggests a potential surgical technique for the treatment of temporal lobe epilepsy. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

  1. Dispersal, habitat differences, and comparative phylogeography of Southeast Asian seahorses (Syngnathidae: Hippocampus).

    Science.gov (United States)

    Lourie, S A; Green, D M; Vincent, A C J

    2005-04-01

    Four distinct phylogeographical patterns across Southeast Asia were observed for four species of seahorse (genus Hippocampus) with differing ecologies. For all species, genetic differentiation (based on cytochrome b sequence comparisons) was significantly associated with sample site (Phi(ST) = 0.190-0.810, P < 0.0001) and with geographical distance (Mantel's r = 0.37-0.59, P < 0.019). Geographic locations of genetic breaks were inconsistent across species in 7/10 comparisons, although some similarities across species were also observed. The two shallow-water species (Hippocampus barbouri and Hippocampus kuda) have colonized the Sunda Shelf to a lesser degree than the two deeper-water species (Hippocampus spinosissimus and Hippocampus trimaculatus). In all species the presence of geographically restricted haplotypes in the Philippines could indicate past population fragmentation and/or long-distance colonization. A nested clade analysis (NCA) revealed that long-distance colonization and/or fragmentation were likely the dominant forces that structure populations of the two shallow-water species, whereas range expansion and restricted dispersal with isolation by distance were proportionally more important in the history of the two deeper-water species. H. trimaculatus has the most widespread haplotypes [average clade distance (D(c)) of nonsingleton haplotypes = 1169 km], indicating potentially high dispersal capabilities, whereas H. barbouri has the least widespread haplotypes (average D(c) = 67 km) indicating potentially lower dispersal capabilities. Pleistocene separation of marine basins and postglacial flooding of the Sunda Shelf are extrinsic factors likely to have contributed to the phylogeographical structure observed, whereas differences among the species appear to reflect their individual ecologies.

  2. Endogenous ghrelin-O-acyltransferase (GOAT) acylates local ghrelin in the hippocampus.

    Science.gov (United States)

    Murtuza, Mohammad I; Isokawa, Masako

    2018-01-01

    Ghrelin is an appetite-stimulating peptide. Serine 3 on ghrelin must be acylated by octanoate via the enzyme ghrelin-O-acyltransferase (GOAT) for the peptide to bind and activate the cognate receptor, growth hormone secretagogue receptor type 1a (GHSR1a). Interest in GHSR1a increased dramatically when GHSR1a mRNA was demonstrated to be widespread in the brain, including the cortex and hippocampus, indicating that it has multifaceted functions beyond the regulation of metabolism. However, the source of octanoylated ghrelin for GHSR1a in the brain, outside of the hypothalamus, is not well understood. Here, we report the presence of GOAT and its ability to acylate non-octanoylated ghrelin in the hippocampus. GOAT immunoreactivity is aggregated at the base of the dentate granule cell layer in the rat and wild-type mouse. This immunoreactivity was not affected by the pharmacological inhibition of GHSR1a or the metabolic state-dependent fluctuation of systemic ghrelin levels. However, it was absent in the GHSR1a knockout mouse hippocampus, pointing the possibility that the expression of GHSR1a may be a prerequisite for the production of GOAT. Application of fluorescein isothiocyanate (FITC)-conjugated non-octanoylated ghrelin in live hippocampal slice culture (but not in fixed culture or in the presence of GOAT inhibitors) mimicked the binding profile of FITC-conjugated octanoylated ghrelin, suggesting that extracellularly applied non-octanoylated ghrelin was acylated by endogenous GOAT in the live hippocampus while GOAT being mobilized out of neurons. Our results will advance the understanding for the role of endogenous GOAT in the hippocampus and facilitate the search for the source of ghrelin that is intrinsic to the brain. © 2017 International Society for Neurochemistry.

  3. Study of the variations in apoptotic factors in hippocampus of male rats with posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Behrang Alani

    2013-01-01

    Full Text Available Background: Post-traumatic stress disorder (PTSD is a stress-related psychosomatic disorder caused by occurrence of a traumatic event and the hippocampus volume of the patients with Post-traumatic stress disorder decreased. However, the mechanisms that cause such damage are not well-understood. The aim of this study is to detect the expression of apoptosis-related Bax, Bcl-2, Caspase-3 and Insulin-like growth Factor-I proteins in the hippocampus region in the Predatory stress rats. Materials and Methods: A total of 70 male wistar rats were divided into Predatory stress groups of 1d, 2d, 3d, 7d, 14d, 30d and a normal control group (N = 10. Rats were subjected to 5 min of predatory stress and then exposed to the elevated plus-maze (EPM. Serum corticosterone and Insulin-like growth factor-1 level of Hippocampus were measured by ELISA technique. The expression of Bax, Bcl-2, and Caspase-3 were detected by western blotting. Results: Rats spent significantly more time in closed arms of the elevated plus maze (EPM than control group after exposure to stress. Serum levels of corticosterone significantly increased at 2d-3d. The expression of hippocampal IGF-1 was significantly up-regulated at 1d-2d after stress. Both Bax and the ratio of Bax/Bcl-2 significantly peaked at Predatory stress 2d-14d. Caspase3 was significantly active among 2d-30 compared to the normal control. Conclusion: The activation of caspase-3 in the stress groups indicates that apoptosis may be one of the reasons inducing hippocampus atrophy and play roles in the pathogenesis of PTSD. Increase in hippocampus levels of IGF-1 during early PTSD might be involved in the early molecular inhibitory mechanism of apoptosis in PTSD.

  4. Differential effects of centrally-active antihypertensives on 5-HT1A receptors in rat dorso-lateral septum, rat hippocampus and guinea-pig hippocampus.

    Science.gov (United States)

    Leishman, D J; Boeijinga, P H; Galvan, M

    1994-01-01

    1. The electrophysiological responses elicited by 5-hydroxytryptamine1A-(5-HT1A) receptor agonists in rat and guinea-pig CA1 pyramidal neurones and rat dorso-lateral septal neurones were compared in vitro by use of conventional intracellular recording techniques. 2. In the presence of 1 microM tetrodotoxin (TTX), to prevent indirect effects, 5-HT, N,N-dipropyl-5-carboxamidotryptamine (DP-5-CT) and 8-hydroxy-2(di-n-propylamino) tetralin (8-OH-DPAT) hyperpolarized the neurones from rat and guinea-pig brain. 3. The hypotensive drug flesinoxan, a selective 5-HT1A receptor agonist, hyperpolarized neurones in all three areas tested; however, another hypotensive agent with high affinity at 5-HT1A-receptors, 5-methyl-urapidil, hyperpolarized only the neurones in rat hippocampus and septum. 4. In guinea-pig hippocampal neurones, 5-methyl-urapidil behaved as a 5-HT1A-receptor antagonist. 5. The relative efficacies (5-HT = 1) of DP-5-CT, 8-OH-DPAT, flesinoxan and 5-methyl-urapidil at the three sites were: rat hippocampus, 1.09, 0.7, 0.5 and 0.24; rat septum, 0.88, 0.69, 0.82 and 0.7; guinea-pig hippocampus, 1.0, 0.69, 0.89 and 0, respectively. 6. It is concluded that the hypotensive agents flesinoxan and 5-methyl-urapidil appear to have different efficacies at 5-HT1A receptors located in different regions of the rodent brain. Whether these regional and species differences arise from receptor plurality or variability in intracellular transduction mechanisms remains to be elucidated.

  5. Prohormone convertase 2 activity is increased in the hippocampus of Wfs1 knockout mice

    Directory of Open Access Journals (Sweden)

    Karin eTein

    2015-08-01

    Full Text Available BackgroundMutations in WFS1 gene cause Wolfram syndrome, which is a rare autosomal recessive disorder, characterized by diabetes insipidus, diabetes mellitus, optic nerve atrophy and deafness (DIDMOAD. The WFS1 gene product wolframin is located in the endoplasmic reticulum. Mice lacking this gene exhibit disturbances in the processing and secretion of peptides, such as vasopressin and insulin. In the brain, high levels of the wolframin protein have been observed in the hippocampus, amygdala and limbic structures. The aim of this study was to investigate the effect of Wfs1 knockout on peptide processing in mouse hippocampus. A peptidomic approach was used to characterize individual peptides in the hippocampus of wild-type and Wfs1 knockout mice. ResultsWe identified 126 peptides in hippocampal extracts and the levels of 10 peptides differed between Wfs1 KO and wild-type mice at P<0.05. The peptide with the largest alteration was little-LEN, which level was 25 times higher in the hippocampus of Wfs1 KO mice compared to wild-type mice. Processing (cleavage of little-LEN from the Pcsk1n gene product proSAAS involves prohormone convertase 2 (PC2. Thus, PC2 activity was measured in extracts prepared from the hippocampus of Wfs1 knockout mice. The activity of PC2 in Wfs1 mutant mice was significantly higher (149.9±2.3%, p<0.0001, n=8 than in wild-type mice (100.0±7.0%, n=8. However, Western blot analysis showed that protein levels of 7B2, proPC2 and PC2 were same in both groups, and so were gene expression levels.ConclusionsProcessing of proSAAS is altered in the hippocampus of Wfs1-KO mice, which is caused by increased activity of PC2. Increased activity of PC2 in Wfs1 knockout mice is not caused by alteration in the levels of PC2 protein. Our results suggest a functional link between Wfs1 and PC2. Thus, the detailed molecular mechanism of the role of Wfs1 in the regulation of PC2 activity needs further investigation.

  6. Influence of prenatal noise and music on the spatial memory and neurogenesis in the hippocampus of developing rats.

    Science.gov (United States)

    Kim, Hong; Lee, Myoung-Hwa; Chang, Hyun-Kyung; Lee, Taeck-Hyun; Lee, Hee-Hyuk; Shin, Min-Chul; Shin, Mal-Soon; Won, Ran; Shin, Hye-Sook; Kim, Chang-Ju

    2006-03-01

    During the prenatal period, the development of individual is influenced by the environmental factors. In the present study, the influence of prenatal noise and music on the spatial memory and neurogenesis in the hippocampus of developing rats was investigated. The exposure to the noise during pregnancy caused growth retardation, decreased neurogenesis in the hippocampus, and impaired spatial learning ability in pups. The exposure to music during pregnancy, on the other hand, caused increased neurogenesis in the hippocampus and enhanced spatial learning ability in pups. The present study has shown the importance of the prenatal environmental conditions for the cognition and brain development.

  7. Gene expression analysis of the emergence of epileptiform activity after focal injection of kainic acid into mouse hippocampus

    DEFF Research Database (Denmark)

    Motti, Dario; Le Duigou, Caroline; Eugène, Emmanuel

    2010-01-01

    and contralateral hippocampus participated in the status epilepticus. However, neuronal death induced by KA treatment was restricted to the injected hippocampus, although there was some contralateral axonal degeneration. We profiled gene expression changes in dorsal and ventral regions of both the injected...... and contralateral hippocampus. Changes were detected in the expression of 1526 transcripts in samples from three time-points: (i) during the KA-induced status epilepticus, (ii) at 2 weeks, before recurrent seizures emerged, and (iii) at 6 months after seizures emerged. Grouping genes with similar spatio...

  8. Hippocampus-dependent retrieval and hippocampus-independent extinction of place avoidance navigation, and stress-induced out-of-context activation of a memory revealed by reversible lesion experiments in rats

    Czech Academy of Sciences Publication Activity Database

    Ježek, Karel; Wesierska, M.; Fenton, André Antonio

    2002-01-01

    Roč. 51, Suppl. 1 (2002), s. S35-S47 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z5011922 Keywords : memory * hippocampus * extinction Subject RIV: FH - Neurology Impact factor: 0.984, year: 2002

  9. The development of the cholinergic system in rat hippocampus following postnatal X-irradiation

    International Nuclear Information System (INIS)

    Ben-Barak, J.

    1981-01-01

    Postnatal X-irradiation of the rat hippocampus results in a marked reduction in the number of the postnatally developing granular neurons in the dentate gyrus and also caused a marked increase in the specific activity of acetylcholinesterase (AChE) and choline acetyltransferase (CAT) and a slight but consistent increase in the activity per whole hippocampus of AChE. The effect of irradiation on the granular neurons and on the cholinergic enzymes was found to be dose and age dependent. Drastic increase in specific enzymatic activities is also observed in the irradiated cerebellum whose granular neurons differentiate postnatally and to a lesser extent in the cerebral cortex in which cell formation is accomplished prior to birth. (Auth.)

  10. Absence of the neurogenesis-dependent nuclear receptor TLX induces inflammation in the hippocampus.

    Science.gov (United States)

    Kozareva, Danka A; Hueston, Cara M; Ó'Léime, Ciarán S; Crotty, Suzanne; Dockery, Peter; Cryan, John F; Nolan, Yvonne M

    2017-08-20

    The orphan nuclear receptor TLX (Nr2e1) is a key regulator of hippocampal neurogenesis. Impaired adult hippocampal neurogenesis has been reported in neurodegenerative and psychiatric conditions including dementia and stress-related depression. Neuroinflammation is also implicated in the neuropathology of these disorders, and has been shown to negatively affect hippocampal neurogenesis. To investigate a role for TLX in hippocampal neuroinflammation, we assessed microglial activation in the hippocampus of mice with a spontaneous deletion of TLX. Results from our study suggest that a lack of TLX is implicated in deregulation of microglial phenotype and that consequently, the survival and function of newborn cells in the hippocampus is impaired. TLX may be an important target in understanding inflammatory-associated impairments in neurogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Structural synaptic plasticity in the hippocampus induced by spatial experience and its implications in information processing.

    Science.gov (United States)

    Carasatorre, M; Ramírez-Amaya, V; Díaz Cintra, S

    2016-10-01

    Long-lasting memory formation requires that groups of neurons processing new information develop the ability to reproduce the patterns of neural activity acquired by experience. Changes in synaptic efficiency let neurons organise to form ensembles that repeat certain activity patterns again and again. Among other changes in synaptic plasticity, structural modifications tend to be long-lasting which suggests that they underlie long-term memory. There is a large body of evidence supporting that experience promotes changes in the synaptic structure, particularly in the hippocampus. Structural changes to the hippocampus may be functionally implicated in stabilising acquired memories and encoding new information. Copyright © 2012 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. The role of the thalamus and hippocampus in episodic memory performance in patients with multiple sclerosis.

    Science.gov (United States)

    Koenig, Katherine A; Rao, Stephen M; Lowe, Mark J; Lin, Jian; Sakaie, Ken E; Stone, Lael; Bermel, Robert A; Trapp, Bruce D; Phillips, Micheal D

    2018-03-01

    Episodic memory loss is one of the most common cognitive symptoms in patients with multiple sclerosis (MS), but the pathophysiology of this symptom remains unclear. Both the hippocampus and thalamus have been implicated in episodic memory and show regional atrophy in patients with MS. In this work, we used functional magnetic resonance imaging (fMRI) during a verbal episodic memory task, lesion load, and volumetric measures of the hippocampus and thalamus to assess the relative contributions to verbal and visual-spatial episodic memory. Functional activation, lesion load, and volumetric measures from 32 patients with MS and 16 healthy controls were used in a predictive analysis of episodic memory function. After adjusting for disease duration, immediate recall performance on a visual-spatial episodic memory task was significantly predicted by hippocampal volume ( p memory measures, functional activation of the thalamus during encoding was more predictive than that of volume measures ( p episodic memory loss in patients with MS.

  13. Neurochemical phenotype of cytoglobin‑expressing neurons in the rat hippocampus

    DEFF Research Database (Denmark)

    Hundahl, Christian Ansgar; Fahrenkrug, Jan; Hannibal, Jens

    2014-01-01

    in a subpopulation of brain neurons. Recently, it has been shown that stress upregulates Cygb expression in the brain and the majority of neuronal nitric oxide synthase (nNOS)-positive neurons, an enzyme that produces NO, co-express Cygb. However, there are more neurons expressing Cygb than nNOS, thus a large number...... of Cygb neurons remain uncharacterized by the neurochemical content. The aim of the present study was to provide an additional and more detailed neurochemical phenotype of Cygb-expressing neurons in the rat hippocampus. The rat hippocampus was chosen due to the abundance of Cygb, as well as this limbic...... structure being an important target in a number of neurodegenerative diseases. Using triple immunohistochemistry, it was demonstrated that nearly all the parvalbumin- and heme oxygenase 1-positive neurons co-express Cygb and to a large extent, these neuron populations are distinct from the population...

  14. Direct Electrical Stimulation of the Human Entorhinal Region and Hippocampus Impairs Memory.

    Science.gov (United States)

    Jacobs, Joshua; Miller, Jonathan; Lee, Sang Ah; Coffey, Tom; Watrous, Andrew J; Sperling, Michael R; Sharan, Ashwini; Worrell, Gregory; Berry, Brent; Lega, Bradley; Jobst, Barbara C; Davis, Kathryn; Gross, Robert E; Sheth, Sameer A; Ezzyat, Youssef; Das, Sandhitsu R; Stein, Joel; Gorniak, Richard; Kahana, Michael J; Rizzuto, Daniel S

    2016-12-07

    Deep brain stimulation (DBS) has shown promise for treating a range of brain disorders and neurological conditions. One recent study showed that DBS in the entorhinal region improved the accuracy of human spatial memory. Based on this line of work, we performed a series of experiments to more fully characterize the effects of DBS in the medial temporal lobe on human memory. Neurosurgical patients with implanted electrodes performed spatial and verbal-episodic memory tasks. During the encoding periods of both tasks, subjects received electrical stimulation at 50 Hz. In contrast to earlier work, electrical stimulation impaired memory performance significantly in both spatial and verbal tasks. Stimulation in both the entorhinal region and hippocampus caused decreased memory performance. These findings indicate that the entorhinal region and hippocampus are causally involved in human memory and suggest that refined methods are needed to use DBS in these regions to improve memory. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Cellular Signal Mechanisms of Reward-Related Plasticity in the Hippocampus

    Directory of Open Access Journals (Sweden)

    Masako Isokawa

    2012-01-01

    Full Text Available The hippocampus has the extraordinary capacity to process and store information. Consequently, there is an intense interest in the mechanisms that underline learning and memory. Synaptic plasticity has been hypothesized to be the neuronal substrate for learning. Ca2+ and Ca2+-activated kinases control cellular processes of most forms of hippocampal synapse plasticity. In this paper, I aim to integrate our current understanding of Ca2+-mediated synaptic plasticity and metaplasticity in motivational and reward-related learning in the hippocampus. I will introduce two representative neuromodulators that are widely studied in reward-related learning (e.g., ghrelin and endocannabinoids and show how they might contribute to hippocampal neuron activities and Ca2+-mediated signaling processes in synaptic plasticity. Additionally, I will discuss functional significance of these two systems and their signaling pathways for its relevance to maladaptive reward learning leading to addiction.

  16. The Interplay of Hippocampus and Ventromedial Prefrontal Cortex in Memory-Based Decision Making

    Directory of Open Access Journals (Sweden)

    Regina A. Weilbächer

    2016-12-01

    Full Text Available Episodic memory and value-based decision making are two central and intensively studied research domains in cognitive neuroscience, but we are just beginning to understand how they interact to enable memory-based decisions. The two brain regions that have been associated with episodic memory and value-based decision making are the hippocampus and the ventromedial prefrontal cortex, respectively. In this review article, we first give an overview of these brain–behavior associations and then focus on the mechanisms of potential interactions between the hippocampus and ventromedial prefrontal cortex that have been proposed and tested in recent neuroimaging studies. Based on those possible interactions, we discuss several directions for future research on the neural and cognitive foundations of memory-based decision making.

  17. Lasting Differential Effects on Plasticity Induced by Prenatal Stress in Dorsal and Ventral Hippocampus

    Directory of Open Access Journals (Sweden)

    Gayane Grigoryan

    2016-01-01

    Full Text Available Early life adversaries have a profound impact on the developing brain structure and functions that persist long after the original traumatic experience has vanished. One of the extensively studied brain structures in relation to early life stress has been the hippocampus because of its unique association with cognitive processes of the brain. While the entire hippocampus shares the same intrinsic organization, it assumes different functions in its dorsal and ventral sectors (DH and VH, resp., based on different connectivity with other brain structures. In the present review, we summarize the differences between DH and VH and discuss functional and structural effects of prenatal stress in the two sectors, with the realization that much is yet to be explored in understanding the opposite reactivity of the DH and VH to stressful stimulation.

  18. Left-right functional asymmetry of ventral hippocampus depends on aversiveness of situations.

    Science.gov (United States)

    Sakaguchi, Yukitoshi; Sakurai, Yoshio

    2017-05-15

    Many studies suggest that animals exhibit lateralized behaviors during aversive situations, and almost all animals exhibit right hemisphere-dominant behaviors associated with fear or anxiety. However, which brain structure in each hemisphere underlies such lateralized function is unclear. In this study, we focused on the hippocampus and investigated the effects of bilateral and unilateral lesions of the ventral hippocampus (VH) on anxiety-like behavior using the successive alleys test. We also examined the expression of c-fos in the VH, which was induced by an aversive situation. Results revealed that consistent right VH dominance trended with the anxiety level. Weaker anxiety induced both right and left VH functions, whereas stronger anxiety induced right VH function. From these results, we conclude that animals are able to adaptively regulate their behaviors to avoid aversive stimuli by changing the functional dominance of their left and right VH. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Hippocampus age-related microstructural changes in schizophrenia: a case-control mean diffusivity study.

    Science.gov (United States)

    Chiapponi, Chiara; Piras, Fabrizio; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco

    2014-08-01

    Macrostructural-volumetric abnormalities of the hippocampus have been described in schizophrenia. Here, we characterized age-related changes of hippocampal mean diffusivity as an index of microstructural damage by carrying out a neuroimaging study in 85 patients with a DSM-IV-TR diagnosis of schizophrenia and 85 age- and gender-matched healthy controls. We performed analyses of covariance, with diagnosis as fixed factor, mean diffusivity as dependent variable and age as covariate. Patients showed an early increase in mean diffusivity in the right and left hippocampus that increased with age. Thus, microstructural hippocampal changes associated with schizophrenia cannot be confined to a specific time window. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Cytoarchitectonic distribution of zinc in the hippocampus of man and the rat

    International Nuclear Information System (INIS)

    Frederickson, C.J.; Klitenick, M.A.; Manton, W.I.; Kirkpatrick, J.B.

    1983-01-01

    Zinc was measured in whole hippocampus and in hippocampal sub-regions by stable-isotope dilution mass spectrometry. Lyophilized tissues were spiked by a precisely-known amount of zinc-64. The zinc-64/zinc-66 isotope ratio was determined by mass spectrometry. In both man and the rat, the most zinc (102-145 ppm, dry weight) was found in the hilar region, the least (27-35) in the fimbria. The amount of zinc directly associated with mossy-fiber axons was estimated to be approximately 8% of the total zinc in the hippocampus, and the concentration of mossy-fiber zinc was estimated at 220-300 μM. Methodological and theoretical implications of the quantitative findings were discussed. (Auth.)

  1. The mitochondrial toxin, 3-nitropropionic acid, induces extracellular Zn2+ accumulation in rat hippocampus slices.

    Science.gov (United States)

    Wei, Guo; Hough, Christopher J; Sarvey, John M

    2004-11-11

    3-nitropropionic acid (3-NPA), a suicide inhibitor of succinate dehydrogenase (SDH; complex II), has been used to provide useful experimental models of Huntington's disease (HD) and "chemical hypoxia" in rodents. The trace ion Zn2+ has been shown to cause neurodegeneration. Employing real-time Newport Green fluorescence imaging of extracellular Zn2+, we found that 3-NPA (10-100 microM) caused a concentration-dependent increase in the concentration of extracellular Zn2+ ([Zn2+]o) in acute rat hippocampus slices. This increase in [Zn2+]o was abolished by 10 mM CaEDTA. The increase of [Zn2+]o was also accompanied by a rapid increase of cytoplasmic-free Zn2+ concentration ([Zn2+]i). The induction of Zn2+ release by 3-MPA in hippocampus slices points to a potential mechanism by which 3-NPA might induce neurodegeneration.

  2. Establishment and maintenance of threatened long snouted seahorse, Hippocampus guttulatus, broodstock in captivity

    OpenAIRE

    Planas, Miguel; Chamorro, Alexandro; Quintas, Patricia; Vilar, Antonio

    2008-01-01

    Knowledge on seahorses is generally scarce but has been increasing in recent years due to their conservation status. Seahorse culture is a quite recent activity in most countries attempting it, and captive breeding techniques are available only for some species. With the aim of contributing to the development of breeding in captivity for conservative purposes, captive broodstock of the European long-snouted seahorse (Hippocampus guttulatus) was established with 32 wild seahorses captured in G...

  3. Brain Circuits of Methamphetamine Place Reinforcement Learning: The Role of the Hippocampus-VTA Loop.

    Science.gov (United States)

    Keleta, Yonas B; Martinez, Joe L

    2012-03-01

    The reinforcing effects of addictive drugs including methamphetamine (METH) involve the midbrain ventral tegmental area (VTA). VTA is primary source of dopamine (DA) to the nucleus accumbens (NAc) and the ventral hippocampus (VHC). These three brain regions are functionally connected through the hippocampal-VTA loop that includes two main neural pathways: the bottom-up pathway and the top-down pathway. In this paper, we take the view that addiction is a learning process. Therefore, we tested the involvement of the hippocampus in reinforcement learning by studying conditioned place preference (CPP) learning by sequentially conditioning each of the three nuclei in either the bottom-up order of conditioning; VTA, then VHC, finally NAc, or the top-down order; VHC, then VTA, finally NAc. Following habituation, the rats underwent experimental modules consisting of two conditioning trials each followed by immediate testing (test 1 and test 2) and two additional tests 24 h (test 3) and/or 1 week following conditioning (test 4). The module was repeated three times for each nucleus. The results showed that METH, but not Ringer's, produced positive CPP following conditioning each brain area in the bottom-up order. In the top-down order, METH, but not Ringer's, produced either an aversive CPP or no learning effect following conditioning each nucleus of interest. In addition, METH place aversion was antagonized by coadministration of the N-methyl-d-aspartate (NMDA) receptor antagonist MK801, suggesting that the aversion learning was an NMDA receptor activation-dependent process. We conclude that the hippocampus is a critical structure in the reward circuit and hence suggest that the development of target-specific therapeutics for the control of addiction emphasizes on the hippocampus-VTA top-down connection.

  4. Diabetes alters KIF1A and KIF5B motor proteins in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Filipa I Baptista

    Full Text Available Diabetes mellitus is the most common metabolic disorder in humans. Diabetic encephalopathy is characterized by cognitive and memory impairments, which have been associated with changes in the hippocampus, but the mechanisms underlying those impairments triggered by diabetes, are far from being elucidated. The disruption of axonal transport is associated with several neurodegenerative diseases and might also play a role in diabetes-associated disorders affecting nervous system. We investigated the effect of diabetes (2 and 8 weeks duration on KIF1A, KIF5B and dynein motor proteins, which are important for axonal transport, in the hippocampus. The mRNA expression of motor proteins was assessed by qRT-PCR, and also their protein levels by immunohistochemistry in hippocampal slices and immunoblotting in total extracts of hippocampus from streptozotocin-induced diabetic and age-matched control animals. Diabetes increased the expression and immunoreactivity of KIF1A and KIF5B in the hippocampus, but no alterations in dynein were detected. Since hyperglycemia is considered a major player in diabetic complications, the effect of a prolonged exposure to high glucose on motor proteins, mitochondria and synaptic proteins in hippocampal neurons was also studied, giving particular attention to changes in axons. Hippocampal cell cultures were exposed to high glucose (50 mM or mannitol (osmotic control; 25 mM plus 25 mM glucose for 7 days. In hippocampal cultures incubated with high glucose no changes were detected in the fluorescence intensity or number of accumulations related with mitochondria in the axons of hippocampal neurons. Nevertheless, high glucose increased the number of fluorescent accumulations of KIF1A and synaptotagmin-1 and decreased KIF5B, SNAP-25 and synaptophysin immunoreactivity specifically in axons of hippocampal neurons. These changes suggest that anterograde axonal transport mediated by these kinesins may be impaired in hippocampal

  5. Factors that Determine the Non-Linear Amygdala Influence on Hippocampus-Dependent Memory

    OpenAIRE

    Akirav, Irit; Richter-Levin, Gal

    2006-01-01

    Stressful experiences are known to either improve or impair hippocampal-dependent memory tasks and synaptic plasticity. These positive and negative effects of stress on the hippocampus have been largely documented, however little is known about the mechanism involved in the twofold influence of stress on hippocampal functioning and about what factors define an enhancing or inhibitory outcome. We have recently demonstrated that activation of the basolateral amygdala can produce a biphasic effe...

  6. Intermittent hypercapnic hypoxia effects on the nicotinic acetylcholine receptors in the developing piglet hippocampus and brainstem.

    Science.gov (United States)

    Vivekanandarajah, Arunnjah; Aishah, Atqiya; Waters, Karen A; Machaalani, Rita

    2017-05-01

    This study investigated the effects of acute (1 day) vs repeated (4 days) exposure to intermittent hypercapnic hypoxia (IHH) on the immunohistochemical expression of α2, α3, α5, α7, α9 and β2 nicotinic acetylcholine receptor (nAChR) subunits in the developing piglet hippocampus and brainstem medulla, and how prior nicotine exposure alters the response to acute IHH. Five piglet groups included: 1day IHH (1D IHH, n=9), 4days IHH (4D IHH, n=8), controls exposed only to air cycles for 1day (1D Air, n=6) or 4days (4D Air, n=5), and pre-exposed to nicotine for 13days prior to 1day IHH (Nic+1D IHH, n=7). The exposure period alternated 6min of HH (8%O 2 , 7%CO 2 , balance N 2 ) and 6min of air over 48min, while controls were switched from air-to-air. Results showed that: 1. repeated IHH induces more changes in nAChR subunit expression than acute IHH in both the hippocampus and brainstem medulla, 2. In the hippocampus, α2 and β2 changed the most (increased) following IHH and the CA3, CA2 and DG were mostly affected. In the brainstem medulla, α2, α5, α9 and β2 were changed (decreased) in most nuclei with the hypoglossal and nucleus of the solitary tract being mostly affected. 3. Pre-exposure to nicotine enhanced the changes in the hippocampus but dampened those in the brainstem medulla. These findings indicate that the nAChRs (predominantly with the α2/β2 complex) are affected by IHH in critical hippocampal and brainstem nuclei during early brain development, and that pre-exposure to nicotine alters the pattern of susceptibility to IHH. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Cocaine withdrawal causes delayed dysregulation of stress genes in the hippocampus.

    Directory of Open Access Journals (Sweden)

    M Julia García-Fuster

    Full Text Available Relapse, even following an extended period of withdrawal, is a major challenge in substance abuse management. Delayed neurobiological effects of the drug during prolonged withdrawal likely contribute to sustained vulnerability to relapse. Stress is a major trigger of relapse, and the hippocampus regulates the magnitude and duration of stress responses. Recent work has implicated hippocampal plasticity in various aspects of substance abuse. We asked whether changes in stress regulatory mechanisms in the hippocampus may participate in the neuroadaptations that occur during prolonged withdrawal. We therefore examined changes in the rat stress system during the course of withdrawal from extended daily access (5-hours of cocaine self-administration, an animal model of addiction. Tissue was collected at 1, 14 and 28 days of withdrawal. Plasma corticosterone levels were determined and corticosteroid receptors (GR, MR, MR/GR mRNA ratios and expression of other stress-related molecules (HSP90AA1 and HSP90AB1 mRNA were measured in hippocampal subfields using in situ hybridization. Results showed a delayed emergence of dysregulation of stress genes in the posterior hippocampus following 28 days of cocaine withdrawal. This included increased GR mRNA in DG and CA3, increased MR and HSP90AA1 mRNA in DG, and decreased MR/GR mRNA ratio in DG and CA1. Corticosterone levels progressively decreased during the course of withdrawal, were normalized following 28 days of withdrawal, and were correlated negatively with GR and positively with MR/GR mRNA ratio in DG. These results suggest a role for the posterior hippocampus in the neuroadaptations that occur during prolonged withdrawal, and point to a signaling partner of GR, HSP90AA1, as a novel dysregulated target during cocaine withdrawal. These delayed neurobiological effects of extended cocaine exposure likely contribute to sustained vulnerability to relapse.

  8. The expression changes of inflammatory cytokines in the hippocampus following whole-brain irradiation in rats

    International Nuclear Information System (INIS)

    Yu De; Tian Ye; Ding Weijun; Zhu Yaqun; Liu Chunfeng

    2004-01-01

    To investigate the change pattern of some inflammatory cytokines in brain tissue at the acute phase after brain irradiated. The whole brain of SD rats was irradiated by the single dose of 2, 15 or 30 Gy of 4 MeV electron beam. The enzyme-linked immunosorbent assay (ELISA) was used for the measurement of IL-1 β, IL-6, and TNF-α content in hippocampus tissue of rats at 1h, 6h, 12h, 1d, 2 and 1 week post-irradiation. The mRNA of IL-1 β, IL-6, and TNF-α were detected by reverse-transcription polymerase chain reaction (RT-PCR) in the same experimental groups. It was analyzed about the influence of dosage and post-irradiation duration with the cytokines expression. Compared with both the normal control and the anesthetized with chloral hydrate but sham-irradiation groups, there were no difference about the three inflammatory cytokines expression in rats with 2 Gy irradiated. At 6h after irradiation with 15 Gy, 6 and 12h with 30 Gy groups, the content of IL-1β and TNF-α in hippocampus tissue were significantly increased, and were returned to normal level after 12 to 24h. The same change tendency of their mRNA relational level was observed in 15 and 30 Gy groups, but it happened earlier in 1h after exposure. Although the content of IL-6 in hippocampus kept stable in all the groups, its mRNA level raised obviously in 12h group. After 15-30 Gy whole-brain irradiation, the expression of some inflammatory cytokines increased abruptly in the hippocampus of SD rat within 1 day, but the interplay between inflammatory cytokines changes and the pathogenesis of radiation injury was incompletely understood at present. (authors)

  9. IDENTIFIKASI JENIS JAMUR ASOSIASI KUDA LAUT Hippocampus barbouriYANG HIDUP DI PERAIRAN ALAMI DAN PENANGKARAN

    OpenAIRE

    Sari, Ratna

    2017-01-01

    Jamur merupakan organisme heterotrof yang menggunakan bahan organik untuk nutrisinya. Jamur dapat sebagai patogen yang bersifat infeksi sekunder. Penyakit yang umum terjadi pada banyak ikan dapat juga terjadi pada kuda laut, diantaranya adalah jamur, parasit dan bakteri.Penelitian ini bertujuan untuk mengetahui jenis-jenisjamuryang berasosiasi dengan kuda laut (Hippocampus barbouri). Jamur asosiasi kuda laut diperoleh dengan metode swab menggunakan cotton swab microbiology. Identifikasi dil...

  10. Genetic disruption of the core circadian clock impairs hippocampus-dependent memory

    OpenAIRE

    2014-01-01

    Perturbing the circadian system by electrolytically lesioning the suprachiasmatic nucleus (SCN) or varying the environmental light:dark schedule impairs memory, suggesting that memory depends on the circadian system. We used a genetic approach to evaluate the role of the molecular clock in memory. Bmal1−/− mice, which are arrhythmic under constant conditions, were examined for hippocampus-dependent memory, LTP at the Schaffer-collateral synapse, and signal transduction activity in the hippoca...

  11. Neural activity in the hippocampus predicts individual visual short-term memory capacity.

    Science.gov (United States)

    von Allmen, David Yoh; Wurmitzer, Karoline; Martin, Ernst; Klaver, Peter

    2013-07-01

    Although the hippocampus had been traditionally thought to be exclusively involved in long-term memory, recent studies raised controversial explanations why hippocampal activity emerged during short-term memory tasks. For example, it has been argued that long-term memory processes might contribute to performance within a short-term memory paradigm when memory capacity has been exceeded. It is still unclear, though, whether neural activity in the hippocampus predicts visual short-term memory (VSTM) performance. To investigate this question, we measured BOLD activity in 21 healthy adults (age range 19-27 yr, nine males) while they performed a match-to-sample task requiring processing of object-location associations (delay period  =  900 ms; set size conditions 1, 2, 4, and 6). Based on individual memory capacity (estimated by Cowan's K-formula), two performance groups were formed (high and low performers). Within whole brain analyses, we found a robust main effect of "set size" in the posterior parietal cortex (PPC). In line with a "set size × group" interaction in the hippocampus, a subsequent Finite Impulse Response (FIR) analysis revealed divergent hippocampal activation patterns between performance groups: Low performers (mean capacity  =  3.63) elicited increased neural activity at set size two, followed by a drop in activity at set sizes four and six, whereas high performers (mean capacity  =  5.19) showed an incremental activity increase with larger set size (maximal activation at set size six). Our data demonstrated that performance-related neural activity in the hippocampus emerged below capacity limit. In conclusion, we suggest that hippocampal activity reflected successful processing of object-location associations in VSTM. Neural activity in the PPC might have been involved in attentional updating. Copyright © 2013 Wiley Periodicals, Inc.

  12. Effects of sleep deprivation on extracellular serotonin in hippocampus and frontal cortex of the rat

    OpenAIRE

    Bjorvatn, B; Grønli, J; Hamre, F; Sørensen, E; Fiske, E; Bjorkum, Alvhild Alette; Portas, CM; Ursin, R

    2002-01-01

    Sleep deprivation improves the mood of depressed patients, but the exact mechanism behind this effect is unclear. An enhancement of serotonergic neurotransmission has been suggested. In this study, we used in vivo microdialysis to monitor extracellular serotonin in the hippocampus and the frontal cortex of rats during an 8 h sleep deprivation period. These brain regions were selected since both have been implicated in depression. The behavioral state of the animal was continuously monitored b...

  13. The human hippocampus is not sexually-dimorphic: Meta-analysis of structural MRI volumes.

    Science.gov (United States)

    Tan, Anh; Ma, Wenli; Vira, Amit; Marwha, Dhruv; Eliot, Lise

    2016-01-01

    Hippocampal atrophy is found in many psychiatric disorders that are more prevalent in women. Sex differences in memory and spatial skills further suggest that males and females differ in hippocampal structure and function. We conducted the first meta-analysis of male-female difference in hippocampal volume (HCV) based on published MRI studies of healthy participants of all ages, to test whether the structure is reliably sexually dimorphic. Using four search strategies, we collected 68 matched samples of males' and females' uncorrected HCVs (in 4418 total participants), and 36 samples of male and female HCVs (2183 participants) that were corrected for individual differences in total brain volume (TBV) or intracranial volume (ICV). Pooled effect sizes were calculated using a random-effects model for left, right, and bilateral uncorrected HCVs and for left and right HCVs corrected for TBV or ICV. We found that uncorrected HCV was reliably larger in males, with Hedges' g values of 0.545 for left hippocampus, 0.526 for right hippocampus, and 0.557 for bilateral hippocampus. Meta-regression revealed no effect of age on the sex difference in left, right, or bilateral HCV. In the subset of studies that reported it, both TBV (g=1.085) and ICV (g=1.272) were considerably larger in males. Accordingly, studies reporting HCVs corrected for individual differences in TBV or ICV revealed no significant sex differences in left and right HCVs (Hedges' g ranging from +0.011 to -0.206). In summary, we found that human males of all ages exhibit a larger HCV than females, but adjusting for individual differences in TBV or ICV results in no reliable sex difference. The frequent claim that women have a disproportionately larger hippocampus than men was not supported. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Anatomic guidelines defined by reformatting images on MRI for volume measurement of amygdala and hippocampus

    International Nuclear Information System (INIS)

    Hoshida, Tohru; Sakaki, Toshisuke; Uematsu, Sumio.

    1995-01-01

    Twelve patients with intractable partial epilepsy underwent MR scans at the Epilepsy Center of the Johns Hopkins Hospital. There were five women and seven men, ranging in age from five to 51 years (mean age: 26 years). Coronal images were obtained using a 3-D SPGR. The coronal images were transferred to an Allegro 5.1 workstation, and reformatted along the cardinal axes (axial and sagittal) in multiple view points. The anterior end of the amygdala was measured at the level just posterior to the disappearance of the temporal stem. The semilunar gyrus of the amygdala was separated from the ambient gyrus by the semianular sulcus that forms the boundary between the amygdala and the entorhinal cortex. The delineation of the hippocampal formation included the subicular complex, hippocampal proper, dentate gyrus, alveus, and fimbria. The uncal cleft separated the uncus above from the parahippocampal gyrus below. The roof of this cleft was formed by the hippocampus and the dentate gyrus, and the floor, by the presubiculum and subiculum. Although using some guidelines, strictly separating the hippocampal head from the posterior part of the amygdala was not feasible as was previously reported, because of the isointensity on MRI between the cortex of the amygdala and the hippocampus. The most posterior portion of the hippocampus was measured at the level of the subsplenial gyri, just below the splenium of the corpus callosum, to measure the hippocampal volume in its near totality. Therefore, it is reliable, and clinically useful, to measure the combined total volume of the amygdala and the hippocampus when comparing results with those of other centers. (S.Y.)

  15. Citrulline diet supplementation improves specific age-related raft changes in wild-type rodent hippocampus.

    Science.gov (United States)

    Marquet-de Rougé, Perrine; Clamagirand, Christine; Facchinetti, Patricia; Rose, Christiane; Sargueil, Françoise; Guihenneuc-Jouyaux, Chantal; Cynober, Luc; Moinard, Christophe; Allinquant, Bernadette

    2013-10-01

    The levels of molecules crucial for signal transduction processing change in the brain with aging. Lipid rafts are membrane microdomains involved in cell signaling. We describe here substantial biophysical and biochemical changes occurring within the rafts in hippocampus neurons from aging wild-type rats and mice. Using continuous sucrose density gradients, we observed light-, medium-, and heavy raft subpopulations in young adult rodent hippocampus neurons containing very low levels of amyloid precursor protein (APP) and almost no caveolin-1 (CAV-1). By contrast, old rodents had a homogeneous age-specific high-density caveolar raft subpopulation containing significantly more cholesterol (CHOL), CAV-1, and APP. C99-APP-Cter fragment detection demonstrates that the first step of amyloidogenic APP processing takes place in this caveolar structure during physiological aging of the rat brain. In this age-specific caveolar raft subpopulation, levels of the C99-APP-Cter fragment are exponentially correlated with those of APP, suggesting that high APP concentrations may be associated with a risk of large increases in beta-amyloid peptide levels. Citrulline (an intermediate amino acid of the urea cycle) supplementation in the diet of aged rats for 3 months reduced these age-related hippocampus raft changes, resulting in raft patterns tightly close to those in young animals: CHOL, CAV-1, and APP concentrations were significantly lower and the C99-APP-Cter fragment was less abundant in the heavy raft subpopulation than in controls. Thus, we report substantial changes in raft structures during the aging of rodent hippocampus and describe new and promising areas of investigation concerning the possible protective effect of citrulline on brain function during aging.

  16. Generalized seizures in the right hippocampus sclerosis combined with hypoplasia of the right vertebral artery

    International Nuclear Information System (INIS)

    Manchev, L.; Toneva, J.; Manolova, T.; Manchev, I.; Valcheva, V.

    2016-01-01

    We present a clinical case of generalized epileptic seizures, occurring suddenly. The common finding from MRI of the brain is sclerosis of the right hippocampus, while MR angiography shows hypoplasia of the right vertebral artery. There are EEG signs for single foci of abnormal activity more on the right side. An anticonvulsant and symptomatic treatment demonstrate a favorable result. Under discussion is the question of surgery treatment. Key words: Hippocampal Sclerosis. MRI. Epileptic Seizures

  17. Intracerebroventricular Injection of Lipopolysaccharide Increases Gene Expression of Connexin32 Gap Junction in Rat Hippocampus

    Directory of Open Access Journals (Sweden)

    Mohammad Abbasian

    2013-11-01

    Full Text Available Introduction: Gap junctions are intercellular membrane channels that provide direct cytoplasmic continuity between adjacent cells. This communication can be affected by changes in expression of gap junctional subunits called Connexins (Cx. Changes in the expression and function of connexins are associated with number of brain neurodegenerative diseases. Neuroinflammation is a hallmark of various central nervous system (CNS diseases, like multiple sclerosis, Alzheimer's disease and epilepsy. Neuroinflammation causes change in Connexins expression. Hippocampus, one of the main brain regions with a wide network of Gap junctions between different neural cell types, has particular vulnerability to damage and consequent inflammation. Cx32 – among Connexins– is expressed in hippocampal Olygodandrocytes and some neural subpopulations. Although multiple lines of evidence indicate that there is an association between neuroinflammation and the expression of connexin, the direct effect of neuroinflammation on the expression of connexins has not been well studied. In the present study, the effect of neuroinflammation induced by the Lipopolysaccharide (LPS on Cx32 gene and protein expressions in rat hippocampus is evaluated. Methods: LPS (2.5μg/rat was infused into the rat cerebral ventricles for 14 days. Cx32 mRNA and protein levels were measured by Real Time PCR and Western Blot after 1st, 7th and 14th injection of LPS in the hippocampus. Results: Significant increase in Cx32 mRNA expression was observed after 7th injection of LPS (P<0.001. However, no significant change was observed in Cx32 protein level. Conclusion: LPS seems to modify Cx32 GJ communication in the hippocampus at transcription level but not at translation or post-translation level. In order to have a full view concerning modification of Cx32 GJ communication, effect of LPS on Cx32 channel gating should also be determined.

  18. A larger hippocampus is associated with longer-lasting spatial memory

    OpenAIRE

    Biegler, Robert; McGregor, Anthony; Krebs, John R.; Healy, Susan D.

    2001-01-01

    Volumetric studies in a range of animals (London taxi-drivers, polygynous male voles, nest-parasitic female cowbirds, and a number of food-storing birds) have shown that the size of the hippocampus, a brain region essential to learning and memory, is correlated with tasks involving an extra demand for spatial learning and memory. In this paper, we report the quantitative advantage that food storers gain from such an enlargement. Coal tits (Parus ater) a food-storin...

  19. Disruption of Inhibitory Function in the Ts65Dn Mouse Hippocampus Through Overexpression of GIRK2

    Science.gov (United States)

    2007-10-24

    embryological and developmental or a result of later problems. Delays in prenatal growth of the Ts65Dn cerebral cortex and hippocampus due to longer...cultured from both DS patients and model animals are also reportedly more vulnerable to apoptosis (Sawa, 1999). A majority of research investigating cell...death in DS has been limited to several apoptosis -related genes, including those related to oxidative stress, and transcription factors overexpressed

  20. Bidirectional global spontaneous network activity precedes the canonical unidirectional circuit organization in the developing hippocampus.

    Science.gov (United States)

    Shi, Yulin; Ikrar, Taruna; Olivas, Nicholas D; Xu, Xiangmin

    2014-06-15

    Spontaneous network activity is believed to sculpt developing neural circuits. Spontaneous giant depolarizing potentials (GDPs) were first identified with single-cell recordings from rat CA3 pyramidal neurons, but here we identify and characterize a large-scale spontaneous network activity we term global network activation (GNA) in the developing mouse hippocampal slices, which is measured macroscopically by fast voltage-sensitive dye imaging. The initiation and propagation of GNA in the mouse is largely GABA-independent and dominated by glutamatergic transmission via AMPA receptors. Despite the fact that signal propagation in the adult hippocampus is strongly unidirectional through the canonical trisynaptic circuit (dentate gyrus [DG] to CA3 to CA1), spontaneous GNA in the developing hippocampus originates in distal CA3 and propagates both forward to CA1 and backward to DG. Photostimulation-evoked GNA also shows prominent backward propagation in the developing hippocampus from CA3 to DG. Mouse GNA is strongly correlated to electrophysiological recordings of highly localized single-cell and local field potential events. Photostimulation mapping of neural circuitry demonstrates that the enhancement of local circuit connections to excitatory pyramidal neurons occurs over the same time course as GNA and reveals the underlying pathways accounting for GNA backward propagation from CA3 to DG. The disappearance of GNA coincides with a transition to the adult-like unidirectional circuit organization at about 2 weeks of age. Taken together, our findings strongly suggest a critical link between GNA activity and maturation of functional circuit connections in the developing hippocampus. Copyright © 2013 Wiley Periodicals, Inc.

  1. The Association of PTSD Symptom Severity with Localized Hippocampus and Amygdala Abnormalities

    Science.gov (United States)

    Akiki, Teddy J.; Averill, Christopher L.; Wrocklage, Kristen M.; Schweinsburg, Brian; Scott, J. Cobb; Martini, Brenda; Averill, Lynnette A.; Southwick, Steven M.; Krystal, John H.; Abdallah, Chadi G.

    2017-01-01

    Background The hippocampus and amygdala have been repeatedly implicated in the psychopathology of posttraumatic stress disorder (PTSD). While numerous structural neuroimaging studies examined these two structures in PTSD, these analyses have largely been limited to volumetric measures. Recent advances in vertex-based neuroimaging methods have made it possible to identify specific locations of subtle morphometric changes within a structure of interest. Methods In this cross-sectional study, we used high-resolution magnetic resonance imaging to examine the relationship between PTSD symptomatology, as measured using the Clinician Administered PTSD Scale for the DSM-IV (CAPS), and structural shape of the hippocampus and amygdala using vertex-wise shape analyses in a group of combat-exposed US Veterans (N = 69). Results Following correction for multiple comparisons and controlling for age and cranial volume, we found that participants with more severe PTSD symptoms showed an indentation in the anterior half of the right hippocampus and an indentation in the dorsal region of the right amygdala (corresponding to the centromedial amygdala). Post hoc analysis using stepwise regression suggest that among PTSD symptom clusters, arousal symptoms explain most of the variance in the hippocampal abnormality, whereas re-experiencing symptoms explain most of the variance in the amygdala abnormality. Conclusion The results provide evidence of localized abnormalities in the anterior hippocampus and centromedial amygdala in combat-exposed US Veterans suffering from PTSD symptoms. This novel finding provides a more fine-grained analysis of structural abnormalities in PTSD and may be informative for understanding the neurobiology of the disorder. PMID:28825050

  2. Role of the hippocampus and orbitofrontal cortex during the disambiguation of social cues in working memory

    Science.gov (United States)

    Ross, Robert S.; LoPresti, Matthew L.; Schon, Karin; Stern, Chantal E.

    2013-01-01

    Human social interactions are complex behaviors requiring the concerted effort of multiple neural systems to track and monitor the individuals around us. Cognitively, adjusting our behavior based on changing social cues such as facial expressions relies on working memory and the ability to disambiguate, or separate, representations of overlapping stimuli resulting from viewing the same individual with different facial expressions. We conducted an fMRI experiment examining brain regions contributing to the encoding, maintenance and retrieval of overlapping identity information during working memory using a delayed match-to-sample (DMS) task. In the overlapping condition, two faces from the same individual with different facial expressions were presented at sample. In the non-overlapping condition, the two sample faces were from two different individuals with different expressions. fMRI activity was assessed by contrasting the overlapping and non-overlapping condition at sample, delay, and test. The lateral orbitofrontal cortex showed increased fMRI signal in the overlapping condition in all three phases of the DMS task and increased functional connectivity with the hippocampus when encoding overlapping stimuli. The hippocampus showed increased fMRI signal at test. These data suggest lateral orbitofrontal cortex helps encode and maintain representations of overlapping stimuli in working memory while the orbitofrontal cortex and hippocampus contribute to the successful retrieval of overlapping stimuli. We suggest the lateral orbitofrontal cortex and hippocampus play a role in encoding, maintaining, and retrieving social cues, especially when multiple interactions with an individual need to be disambiguated in a rapidly changing social context in order to make appropriate social responses. PMID:23640112

  3. Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhenlie [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Department of Toxicology, Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou 510‐300 (China); Ichihara, Sahoko [Graduate School of Regional Innovation Studies, Mie University, Tsu 514‐8507 (Japan); Oikawa, Shinji [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514‐8507 (Japan); Chang, Jie; Zhang, Lingyi; Subramanian, Kaviarasan; Mohideen, Sahabudeen Sheik [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Ichihara, Gaku, E-mail: gak@med.nagoya-u.ac.jp [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan)

    2012-08-15

    1-Bromopropane (1-BP) is neurotoxic in both experimental animals and humans. Previous proteomic analysis of rat hippocampus implicated alteration of protein expression in oxidative stress, suggesting that oxidative stress plays a role in 1-BP-induced neurotoxicity. To understand this role at the protein level, we exposed male F344 rats to 1-BP at 0, 400, or 1000 ppm for 8 h/day for 1 week or 4 weeks by inhalation and quantitated changes in hippocampal protein carbonyl using a protein carbonyl assay, two-dimensional gel electrophoresis (2-DE), immunoblotting, and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF/MS). Hippocampal reactive oxygen species and protein carbonyl were significantly increased, demonstrating 1-BP-associated induction of oxidative stress and protein damage. MALDI-TOF-TOF/MS identified 10 individual proteins with increased carbonyl modification (p < 0.05; fold-change ≥ 1.5). The identified proteins were involved in diverse biological processes including glycolysis, ATP production, tyrosine catabolism, GTP binding, guanine degradation, and neuronal metabolism of dopamine. Hippocampal triosephosphate isomerase (TPI) activity was significantly reduced and negatively correlated with TPI carbonylation (p < 0.001; r = 0.83). Advanced glycation end-product (AGE) levels were significantly elevated both in the hippocampus and plasma, and hippocampal AGEs correlated negatively with TPI activity (p < 0.001; r = 0.71). In conclusion, 1-BP-induced neurotoxicity in the rat hippocampus seems to involve oxidative damage of cellular proteins, decreased TPI activity, and elevated AGEs. -- Highlights: ► 1-BP increases hippocampal ROS levels and hippocampal and plasma protein carbonyls. ► 1-BP increases TPI carbonylation and decreases TPI activity in the hippocampus. ► 1-BP increases hippocampal and plasma AGE levels.

  4. Abnormal neural precursor cell regulation in the early postnatal Fragile X mouse hippocampus.

    Science.gov (United States)

    Sourial, Mary; Doering, Laurie C

    2017-07-01

    The regulation of neural precursor cells (NPCs) is indispensable for a properly functioning brain. Abnormalities in NPC proliferation, differentiation, survival, or integration have been linked to various neurological diseases including Fragile X syndrome. Yet, no studies have examined NPCs from the early postnatal Fragile X mouse hippocampus despite the importance of this developmental time point, which marks the highest expression level of FMRP, the protein missing in Fragile X, in the rodent hippocampus and is when hippocampal NPCs have migrated to the dentate gyrus (DG) to give rise to lifelong neurogenesis. In this study, we examined NPCs from the early postnatal hippocampus and DG of Fragile X mice (Fmr1-KO). Immunocytochemistry on neurospheres showed increased Nestin expression and decreased Ki67 expression, which collectively indicated aberrant NPC biology. Intriguingly, flow cytometric analysis of the expression of the antigens CD15, CD24, CD133, GLAST, and PSA-NCAM showed a decreased proportion of neural stem cells (GLAST + CD15 + CD133 + ) and an increased proportion of neuroblasts (PSA-NCAM + CD15 + ) in the DG of P7 Fmr1-KO mice. This was mirrored by lower expression levels of Nestin and the mitotic marker phospho-histone H3 in vivo in the P9 hippocampus, as well as a decreased proportion of cells in the G 2 /M phases of the P7 DG. Thus, the absence of FMRP leads to fewer actively cycling NPCs, coinciding with a decrease in neural stem cells and an increase in neuroblasts. Together, these results show the importance of FMRP in the developing hippocampal formation and suggest abnormalities in cell cycle regulation in Fragile X. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  5. Alternative conceptions of memory consolidation and the role of the hippocampus at the systems level in rodents.

    Science.gov (United States)

    Sutherland, R J; Lehmann, H

    2011-06-01

    We discuss very recent experiments with rodents addressing the idea that long-term memories initially depending on the hippocampus, over a prolonged period, become independent of it. No unambiguous recent evidence exists to substantiate that this occurs. Most experiments find that recent and remote memories are equally affected by hippocampus damage. Nearly all experiments that report spared remote memories suffer from two problems: retrieval could be based upon substantial regions of spared hippocampus and recent memory is tested at intervals that are of the same order of magnitude as cellular consolidation. Accordingly, we point the way beyond systems consolidation theories, both the Standard Model of Consolidation and the Multiple Trace Theory, and propose a simpler multiple storage site hypothesis. On this view, with event reiterations, different memory representations are independently established in multiple networks. Many detailed memories always depend on the hippocampus; the others may be established and maintained independently. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Effects of visual deprivation during brain development on expression of AMPA receptor subunits in rat’s hippocampus

    Directory of Open Access Journals (Sweden)

    Sayyed Alireza Talaei

    2015-06-01

    Conclusion: Dark rearing of rats during critical period of brain development changes the relative expression and also arrangement of both AMPA receptor subunits, GluR1 and GluR2 in the hippocampus, age dependently.

  7. 5-HT2A Serotonin Receptor Density in Adult Male Rats’ Hippocampus after Morphine-based Conditioned Place Preference

    Directory of Open Access Journals (Sweden)

    Rabie Mohammadi

    2016-07-01

    Conclusion: We concluded that the phenomenon of conditioned place preference induced by morphine can cause a significant increase in the number of serotonin 5-HT2A receptors in neurons of all areas of hippocampus.

  8. DEVELOPMENTAL HYPOTHYROIDISM REDUCES PARVALBUMIN EXPRESSION IN GABAERGIC NEURONS OF CORTEX AND HIPPOCAMPUS: IMMUNOHISTOCHEMICAL FINDINGS AND FUNCTIONAL CORRELATES.

    Science.gov (United States)

    GABAergic interneurons comprise the bulk of local inhibitory neuronal circuitry in cortex and hippocampus and a subpopulation of these interneurons contain the calcium binding protein, parvalbumin (PV). A previous report indicated that severe hypothyroidism reduced PV immunoreact...

  9. Hippocampus lesions induced deficits in social and spatial recognition in Octodon degus.

    Science.gov (United States)

    Uekita, Tomoko; Okanoya, Kazuo

    2011-06-01

    Previous studies of rodents reported that the hippocampus plays an important role in social behavior as well as spatial behavior. However, there are inconsistencies between reports of the effects of hippocampal lesions on social behavior. The present study sought to clarify the aspects of social behavior in which the hippocampus plays a role in the degu, Octodon degus, a social rodent. We examined the effects of hippocampal lesions on social behavior in the degu using familiar and novel partners. When placed in a familiar environment with a familiar partner after surgery, sham operation control (S.Cont) degus exhibited affinitive behavior longer compared with hippocampal lesioned (HPC) degus. In a novel environment, S.Cont degus exhibited longer aggressive behavior toward novel partners, and longer affinitive behavior with familiar partners compared with HPC degus. HPC degus did not show evidence of differentiation in social behavior, regardless of partner's novelty. The results of an anxiety test confirmed that these findings could not be attributed to changes in emotional state. We conducted an object-recognition test with the same subjects. HPC degus showed an impairment in spatial recognition but not object recognition. Taken together, these results suggest that the degu hippocampus plays an important role not only in spatial recognition but also social recognition. The changes in social behavior resulting from hippocampal lesions were interpreted as due to an impairment of social recognition rather than an impairment in novelty detection. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Dopamine Regulates Aversive Contextual Learning and Associated In Vivo Synaptic Plasticity in the Hippocampus

    Directory of Open Access Journals (Sweden)

    John I. Broussard

    2016-03-01

    Full Text Available Dopamine release during reward-driven behaviors influences synaptic plasticity. However, dopamine innervation and release in the hippocampus and its role during aversive behaviors are controversial. Here, we show that in vivo hippocampal synaptic plasticity in the CA3-CA1 circuit underlies contextual learning during inhibitory avoidance (IA training. Immunohistochemistry and molecular techniques verified sparse dopaminergic innervation of the hippocampus from the midbrain. The long-term synaptic potentiation (LTP underlying the learning of IA was assessed with a D1-like dopamine receptor agonist or antagonist in ex vivo hippocampal slices and in vivo in freely moving mice. Inhibition of D1-like dopamine receptors impaired memory of the IA task and prevented the training-induced enhancement of both ex vivo and in vivo LTP induction. The results indicate that dopamine-receptor signaling during an aversive contextual task regulates aversive memory retention and regulates associated synaptic mechanisms in the hippocampus that likely underlie learning.

  11. Theta oscillation and neuronal activity in rat hippocampus areinvolved in temporal discrimination of time in seconds

    Directory of Open Access Journals (Sweden)

    Tomoaki eNakazono

    2015-06-01

    Full Text Available The discovery of time cells revealed that the rodent hippocampus has information of time.Previous studies have suggested that a role of hippocampal time cells is to integratetemporally segregated events into a sequence using working memory with time perception.However, it is unclear that hippocampal cells contribute to time perception itself becausemost previous studies employed delayed matching-to-sample tasks that did not evaluatetime perception separately from working memory processes. Here, we investigated thefunction of the rat hippocampus in time perception using a temporal discrimination task. Inthe task, rats had to discriminate between durations of 1 and 3 sec to get a reward, andmaintaining task-related information as working memory was not required. We found thatsome hippocampal neurons showed firing rate modulation similar to that of time cells.Moreover, theta oscillation of local field potentials (LFPs showed a transient enhancementof power during time discrimination periods. However, there were little relationshipsbetween the neuronal activities and theta oscillations. These results suggest that both theindividual neuronal activities and theta oscillations of LFPs in the hippocampus have a possibility to be engaged in seconds order time perception; however, they participate in different ways.

  12. Subregion-Specific Proteomic Signature in the Hippocampus for Recognition Processes in Adult Mice

    Directory of Open Access Journals (Sweden)

    Lukas M. von Ziegler

    2018-03-01

    Full Text Available Summary: The hippocampal formation is a brain structure essential for higher-order cognitive functions. It has a complex anatomical organization and cellular composition, and hippocampal subregions have different properties and functional roles. In this study, we used SWATH-MS to determine whether the proteomes of hippocampus areas CA1 and CA3 can explain the commonalities or specificities of these subregions in basal conditions and after recognition memory. We show that the proteomes of areas CA1 and CA3 are largely different in basal conditions and that differential changes and dynamics in protein expression are induced in these areas after recognition of an object or object location. While changes are consistent across both recognition paradigms in area CA1, they are not in area CA3, suggesting distinct proteomic responses in areas CA1 and CA3 for memory formation. : How does the proteome differ in hippocampus areas CA1 and CA3? von Ziegler et al. identify the proteomes of areas CA1 and CA3 and characterize their dynamics during different recognition processes in adult mice. Keywords: hippocampus, areas CA1 and CA3, proteome, dynamics, object memory, object location memory, mass spectrometry, SWATH-MS, mice, bioinformatic tools

  13. Effects of Asiatic Acid on Spatial Working Memory and Cell Proliferation in the Adult Rat Hippocampus

    Directory of Open Access Journals (Sweden)

    Apiwat Sirichoat

    2015-10-01

    Full Text Available Asiatic acid is a pentacyclic triterpene from Centella asiatica. Previous studies have reported that asiatic acid exhibits antioxidant and neuroprotective activities in cell culture. It also prevents memory deficits in animal models. The objective of this study was to investigate the relationship between spatial working memory and changes in cell proliferation within the hippocampus after administration of asiatic acid to male Spraque-Dawley rats. Control rats received vehicle (propylene glycol while treated rats received asiatic acid (30 mg/kg orally for 14 or 28 days. Spatial memory was determined using the novel object location (NOL test. In animals administered asiatic acid for both 14 and 28 days, the number of Ki-67 positive cells in the subgranular zone of the dentate gyrus was significantly higher than in control animals. This was associated with a significant increase in their ability to discriminate between novel and familiar object locations in a novel object discrimination task, a hippocampus-dependent spatial memory test. Administration of asiatic acid also significantly increased doublecortin (DCX and Notch1 protein levels in the hippocampus. These findings demonstrate that asiatic acid treatment may be a potent cognitive enhancer which improves hippocampal-dependent spatial memory, likely by increasing hippocampal neurogenesis.

  14. Is the hippocampus necessary for visual and verbal binding in working memory?

    Science.gov (United States)

    Baddeley, Alan; Allen, Richard; Vargha-Khadem, Faraneh

    2010-03-01

    A series of experiments test the recent claim that the hippocampus is necessary for the binding of features in working memory. Some potential limitations of studies underlying this claim are discussed, and an attempt is made to further test the hypothesis by studying a case of developmental amnesia whose extensively investigated pathology appears to be principally limited to the hippocampus, and who shows the expected deficit in episodic long-term memory. One series of experiments studied the short-term visual binding of color and shape under conditions ranging from simple presentation of colored objects through the more demanding task of combining the features when separated in space, or in time. A second set of experiments studied the capacity to use sentence structure to bind words into chunks in short-term verbal memory. Hippocampal pathology did not lead to a decrement on any of these tasks, suggesting that the hippocampus is not essential for short-term binding in working memory. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  15. Enhanced synaptic activity and epileptiform events in the embryonic Kcc2 deficient hippocampus

    Directory of Open Access Journals (Sweden)

    Ilgam eKhalilov

    2011-11-01

    Full Text Available The neuronal potassium-chloride co-transporter Kcc2 is thought to play an important role in the post natal excitatory to inhibitory switch of GABA actions in the rodent hippocampus. Here, by studying hippocampi of wild-type (Kcc2+/+ and Kcc2 deficient (Kcc2-/- mouse embryos, we unexpectedly found increased spontaneous neuronal network activity at E18.5, a developmental stage when Kcc2 is thought not to be functional in the hippocampus. Embryonic Kcc2-/- hippocampi have also an augmented synapse density and a higher frequency of spontaneous glutamatergic and GABAergic postsynaptic currents (PSCs than naïve age matched neurons. However, intracellular chloride concentration ([Cl-]i and the reversal potential of GABA-mediated currents (EGABA were similar in embryonic Kcc2+/+ and Kcc2-/- CA3 neurons. In addition, Kcc2 immuno-labelling was cytoplasmic in the majority of neurons suggesting that the molecule is not functional as a plasma membrane chloride co-transporter. Collectively, our results show that already at an embryonic stage, Kcc2 controls the formation of synapses and, when deleted, the hippocampus has a higher density of GABAergic and glutamatergic synapses and generates spontaneous and evoked epileptiform activities. These results may be explained either by a small population of orchestrating neurons in which Kcc2 operates early as a chloride exporter or by transporter independent actions of Kcc2 that are instrumental in synapses formation and networks construction.

  16. A Mathematical Model for the Hippocampus: Towards the Understanding of Episodic Memory and Imagination

    Science.gov (United States)

    Tsuda, I.; Yamaguti, Y.; Kuroda, S.; Fukushima, Y.; Tsukada, M.

    How does the brain encode episode? Based on the fact that the hippocampus is responsible for the formation of episodic memory, we have proposed a mathematical model for the hippocampus. Because episodic memory includes a time series of events, an underlying dynamics for the formation of episodic memory is considered to employ an association of memories. David Marr correctly pointed out in his theory of archecortex for a simple memory that the hippocampal CA3 is responsible for the formation of associative memories. However, a conventional mathematical model of associative memory simply guarantees a single association of memory unless a rule for an order of successive association of memories is given. The recent clinical studies in Maguire's group for the patients with the hippocampal lesion show that the patients cannot make a new story, because of the lack of ability of imagining new things. Both episodic memory and imagining things include various common characteristics: imagery, the sense of now, retrieval of semantic information, and narrative structures. Taking into account these findings, we propose a mathematical model of the hippocampus in order to understand the common mechanism of episodic memory and imagination.

  17. Leukocyte telomere length and hippocampus volume: a meta-analysis [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Gustav Nilsonne

    2015-10-01

    Full Text Available Leukocyte telomere length has been shown to correlate to hippocampus volume, but effect estimates differ in magnitude and are not uniformly positive. This study aimed primarily to investigate the relationship between leukocyte telomere length and hippocampus gray matter volume by meta-analysis and secondarily to investigate possible effect moderators. Five studies were included with a total of 2107 participants, of which 1960 were contributed by one single influential study. A random-effects meta-analysis estimated the effect to r = 0.12 [95% CI -0.13, 0.37] in the presence of heterogeneity and a subjectively estimated moderate to high risk of bias. There was no evidence that apolipoprotein E (APOE genotype was an effect moderator, nor that the ratio of leukocyte telomerase activity to telomere length was a better predictor than leukocyte telomere length for hippocampus volume. This meta-analysis, while not proving a positive relationship, also is not able to disprove the earlier finding of a positive correlation in the one large study included in analyses. We propose that a relationship between leukocyte telomere length and hippocamus volume may be mediated by transmigrating monocytes which differentiate into microglia in the brain parenchyma.

  18. Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study

    International Nuclear Information System (INIS)

    Lee, S.K.; Kim, D.W.; Kim, K.K.; Chung, C.K.; Song, I.C.; Chang, K.H.

    2005-01-01

    This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. (orig.)

  19. Hebb, pandemonium and catastrophic hypermnesia: the hippocampus as a suppressor of inappropriate associations.

    Science.gov (United States)

    McNaughton, Neil; Wickens, Jeff

    2003-01-01

    The hippocampus has been proposed as a key component of a "behavioural inhibition system". We explore the implications of this idea for the nature of associative memory--i.e. learning that is distinct from the moulding of response sequences by error correction and reinforcement. It leads to the view that all associative memory depends on purely Hebbian mechanisms. Memories involve acquisition of new goals not the strengthening of new stimulus-response links. Critically, memories will consist of affectively positive and affectively negative associations as well "purely cognitive" information. The hippocampus is seen as a supervisor that is normally "just checking" information about current available goals. When one available goal is pre-eminent there is no hippocampal output and the goal controls the response system. When two or more goals are similarly and highly primed there is conflict. This is detected by the hippocampus which sends output that increases the valence of affectively negative perceptions and so resolves the conflict by suppressing more aversive goals. Such conflict resolution occurs with innate as well as acquired goals and is fundamentally non-memorial. But, in memory paradigms, it can often act to suppress interference on the current trial and, through Hebbian association of the increase in negative affect, decrease the probability of interference on later trials and during consolidation. Both memory-driven and innate behaviour is made hippocampal-dependent by innate and acquired conflicting tendencies and not the class of stimulus presented.

  20. Inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear.

    Science.gov (United States)

    Jiang, Lizhu; Mao, Rongrong; Tong, Jianbin; Li, Jinnan; Chai, Anping; Zhou, Qixin; Yang, Yuexiong; Wang, Liping; Li, Lingjiang; Xu, Lin

    2016-10-01

    Promoting extinction of fear memory is the main treatment of fear disorders, especially post-traumatic stress disorder (PTSD). However, fear extinction is often incomplete in these patients. Our previous study had shown that Rac1 activity in hippocampus plays a crucial role in the learning of contextual fear memory in rats. Here, we further investigated whether Rac1 activity also modulated the extinction of contextual fear memory. We found that massed extinction obviously upregulated hippocampal Rac1 activity and induced long-term extinction of contextual fear in rats. Intrahippocampal injection of the Rac1 inhibitor NSC23766 prevents extinction of contextual fear in massed extinction training rats. In contrast, long-spaced extinction downregulated Rac1 activity and caused less extinction. And Rac1 activator CN04-A promotes extinction of contextual fear in long-spaced extinction rats. Our study demonstrates that inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear, suggesting that modulating Rac1 activity of the hippocampus may be promising therapy of fear disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.K.; Kim, D.W.; Kim, K.K. [Seoul National University College of Medicine, Seoul National University Hospital, Department of Neurology, Chongno ku, Seoul (Korea); Chung, C.K. [Seoul National University College of Medicine, Seoul National University Hospital, Department of Neurosurgery, Chongno ku, Seoul (Korea); Song, I.C.; Chang, K.H. [Seoul National University College of Medicine, Seoul National University Hospital, Department of Radiology, Chongno ku, Seoul (Korea)

    2005-12-01

    This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. (orig.)

  2. Ablation of BRaf impairs neuronal differentiation in the postnatal hippocampus and cerebellum.

    Directory of Open Access Journals (Sweden)

    Verena Pfeiffer

    Full Text Available This study focuses on the role of the kinase BRaf in postnatal brain development. Mice expressing truncated, non-functional BRaf in neural stem cell-derived brain tissue demonstrate alterations in the cerebellum, with decreased sizes and fuzzy borders of the glomeruli in the granule cell layer. In addition we observed reduced numbers and misplaced ectopic Purkinje cells that showed an altered structure of their dendritic arborizations in the hippocampus, while the overall cornus ammonis architecture appeared to be unchanged. In male mice lacking BRaf in the hippocampus the size of the granule cell layer was normal at postnatal day 12 (P12 but diminished at P21, as compared to control littermates. This defect was caused by a reduced ability of dentate gyrus progenitor cells to differentiate into NeuN positive granule cell neurons. In vitro cell culture of P0/P1 hippocampal cells revealed that BRaf deficient cells were impaired in their ability to form microtubule-associated protein 2 positive neurons. Together with the alterations in behaviour, such as autoaggression and loss of balance fitness, these observations indicate that in the absence of BRaf all neuronal cellular structures develop, but neuronal circuits in the cerebellum and hippocampus are partially disturbed besides impaired neuronal generation in both structures.

  3. Early Life Stress Effects on Glucocorticoid—BDNF Interplay in the Hippocampus

    Science.gov (United States)

    Daskalakis, Nikolaos P.; De Kloet, Edo Ronald; Yehuda, Rachel; Malaspina, Dolores; Kranz, Thorsten M.

    2015-01-01

    Early life stress (ELS) is implicated in the etiology of multiple psychiatric disorders. Important biological effects of ELS are manifested in stress-susceptible regions of the hippocampus and are partially mediated by long-term effects on glucocorticoid (GC) and/or neurotrophin signaling pathways. GC-signaling mediates the regulation of stress response to maintain homeostasis, while neurotrophin signaling plays a key role in neuronal outgrowth and is crucial for axonal guidance and synaptic integrity. The neurotrophin and GC-signaling pathways co-exist throughout the central nervous system (CNS), particularly in the hippocampus, which has high expression levels of glucocorticoid-receptors (GR) and mineralocorticoid-receptors (MR) as well as brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase receptor B (TrkB). This review addresses the effects of ELS paradigms on GC- and BDNF-dependent mechanisms and their crosstalk in the hippocampus, including potential implications for the pathogenesis of common stress-related disorders. PMID:26635521

  4. Early Life Stress Effects on the Glucocorticoid - BDNF interplay in the Hippocampus

    Directory of Open Access Journals (Sweden)

    Nikolaos P Daskalakis

    2015-11-01

    Full Text Available Early life stress (ELS is implicated in the etiology of multiple psychiatric disorders. Important biological effects of ELS are manifested in stress-susceptible regions of the hippocampus and are partially mediated by long-term effects on glucocorticoid and/or neurotrophin signaling pathways. Glucocorticoid (GC signaling mediates the regulation of the stress response to maintain homeostasis, while neurotrophin signaling plays a key role in neuronal outgrowth and is crucial for axonal guidance and synaptic integrity. The neurotrophin and glucocorticoid signaling pathways co-exist throughout the central nervous system (CNS, particularly in the hippocampus, which has high expression of glucocorticoid and mineralocorticoid receptors (GR and MR as well as brain-derived neurotrophic factor (BDNF and its receptor, tropomyosin-related kinase receptor B (TrkB. This review addresses the effects of ELS paradigms on GC- and BDNF- dependent mechanisms and their crosstalk in the hippocampus, including potential implications for the pathogenesis of common stress-related disorders.

  5. Structural development of the hippocampus and episodic memory: developmental differences along the anterior/posterior axis.

    Science.gov (United States)

    DeMaster, Dana; Pathman, Thanujeni; Lee, Joshua K; Ghetti, Simona

    2014-11-01

    The hippocampus is critically involved in episodic memory, yet relatively little is known about how the development of this structure contributes to the development of episodic memory during middle to late childhood. Previous research has inconsistently reported associations between hippocampal volume and episodic memory performance during this period. We argue that this inconsistency may be due to assessing the hippocampus as a whole, and propose to examine associations separately for subregions along the longitudinal axis of the hippocampus. In the present study, we examined age-related differences in volumes of the hippocampal head, body, and tail, and collected episodic memory measures in children ages 8-11 years and young adults (N = 62). We found that adults had a smaller right hippocampal head, larger hippocampal body bilaterally, and smaller right hippocampal tail compared with children. In adults, but not in children, better episodic memory performance was associated with smaller right hippocampal head and larger hippocampal body. In children, but not in adults, better episodic memory was associated with larger left hippocampal tail. Overall, the results suggest that protracted development of hippocampal subregions contribute to age-related differences in episodic memory. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. The Insulin Regulatory Network in Adult Hippocampus and Pancreatic Endocrine System

    Directory of Open Access Journals (Sweden)

    Masanao Machida

    2012-01-01

    Full Text Available There is a very strong correlation between the insulin-mediated regulatory system of the central nervous system and the pancreatic endocrine system. There are many examples of the same transcriptional factors being expressed in both regions in their embryonic development stages. Hormonal signals from the pancreatic islets influence the regulation of energy homeostasis by the brain, and the brain in turn influences the secretions of the islets. Diabetes induces neuronal death in different regions of the brain especially hippocampus, causes alterations on the neuronal circuits and therefore impairs learning and memory, for which the hippocampus is responsible. The hippocampus is a region of the brain where steady neurogenesis continues throughout life. Adult neurogenesis from undifferentiated neural stem cells is greatly decreased in diabetic patients, and as a result their learning and memory functions decline. Might it be possible to reactivate stem cells whose functions have deteriorated and that are present in the tissues in which the lesions occur in diabetes, a lifestyle disease, which plagues modern humans and develops as a result of the behavior of insulin-related factor? In this paper we summarize research in regard to these matters based on examples in recent years.

  7. Epistasis between dopamine regulating genes identifies a nonlinear response of the human hippocampus during memory tasks.

    Science.gov (United States)

    Bertolino, Alessandro; Di Giorgio, Annabella; Blasi, Giuseppe; Sambataro, Fabio; Caforio, Grazia; Sinibaldi, Lorenzo; Latorre, Valeria; Rampino, Antonio; Taurisano, Paolo; Fazio, Leonardo; Romano, Raffaella; Douzgou, Sofia; Popolizio, Teresa; Kolachana, Bhaskar; Nardini, Marcello; Weinberger, Daniel R; Dallapiccola, Bruno

    2008-08-01

    Dopamine modulation of neuronal activity in prefrontal cortex maps to an inverted U-curve. Dopamine is also an important factor in regulation of hippocampal mediated memory processing. Here, we investigated the effect of genetic variation of dopamine inactivation via catechol-O-methyltransferase (COMT) and the dopamine transporter (DAT) on hippocampal activity in healthy humans during different memory conditions. Using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in 82 subjects matched for a series of demographic and genetic variables, we studied the effect of the COMT valine (Val)(158)methionine (Met) and the DAT 3' variable number tandem repeat (VNTR) polymorphisms on function of the hippocampus during encoding of recognition memory and during working memory. Our results consistently demonstrated a double dissociation so that DAT 9-repeat carrier alleles modulated activity in the hippocampus in the exact opposite direction of DAT 10/10-repeat alleles based on COMT Val(158)Met genotype during different memory conditions. Similar results were evident in ventrolateral and dorsolateral prefrontal cortex. These findings suggest that genetically determined dopamine signaling during memory processing maps to a nonlinear relationship also in the hippocampus. Our data also demonstrate in human brain epistasis of two genes implicated in dopamine signaling on brain activity during different memory conditions.

  8. Differential proliferation rhythm of neural progenitor and oligodendrocyte precursor cells in the young adult hippocampus.

    Directory of Open Access Journals (Sweden)

    Yoko Matsumoto

    Full Text Available Oligodendrocyte precursor cells (OPCs are a unique type of glial cells that function as oligodendrocyte progenitors while constantly proliferating in the normal condition from rodents to humans. However, the functional roles they play in the adult brain are largely unknown. In this study, we focus on the manner of OPC proliferation in the hippocampus of the young adult mice. Here we report that there are oscillatory dynamics in OPC proliferation that differ from neurogenesis in the subgranular zone (SGZ; the former showed S-phase and M-phase peaks in the resting and active periods, respectively, while the latter only exhibited M-phase peak in the active period. There is coincidence between different modes of proliferation and expression of cyclin proteins that are crucial for cell cycle; cyclin D1 is expressed in OPCs, while cyclin D2 is observed in neural stem cells. Similar to neurogenesis, the proliferation of hippocampal OPCs was enhanced by voluntary exercise that leads to an increase in neuronal activity in the hippocampus. These data suggest an intriguing control of OPC proliferation in the hippocampus.

  9. A critical role of the human hippocampus in an electrophysiological measure of implicit memory

    Science.gov (United States)

    Addante, Richard James

    2015-01-01

    The hippocampus has traditionally been thought to be critical for conscious explicit memory but not necessary for unconscious implicit memory processing. In a recent study of a group of mild amnesia patients with evidence of MTL damage limited to the hippocampus, subjects were tested on a direct test of item recognition confidence while electroencephalogram (EEG) was acquired, and revealed intact measures of explicit memory from 400–600ms (mid-frontal old-new effect, FN400). The current investigation re-analyzed this data to study event-related potentials (ERPs) of implicit memory, using a recently developed procedure that eliminated declarative memory differences. Prior ERP findings from this technique were first replicated in two independent matched control groups, which exhibited reliable implicit memory effects in posterior scalp regions from 400–600 msec, which were topographically dissociated from the explicit memory effects of familiarity. However, patients were found to be dramatically impaired in implicit memory effects relative to control subjects, as quantified by a reliable condition × group interaction. Several control analysis were conducted to consider alternative factors that could account for the results, including outliers, sample size, age, or contamination by explicit memory, and each of these factors were systematically ruled out. Results suggest that the hippocampus plays a fundamental role in aspects of memory processing that is beyond conscious awareness. The current findings therefore indicate that both memory systems of implicit and explicit memory may rely upon the same neural structures – but function in different physiological ways. PMID:25562828

  10. Increased CSF-BACE1 activity associated with decreased hippocampus volume in Alzheimer's disease.

    LENUS (Irish Health Repository)

    Ewers, Michael

    2012-02-01

    The enzyme beta-secretase (BACE1) is essentially involved in the production of cerebral amyloidogenic pathology in Alzheimer\\'s disease (AD). The measurement of BACE1 activity in cerebrospinal fluid (CSF) has been reported, which may render CSF measurement of BACE1 a potential biomarker candidate of AD. In order to investigate whether BACE1 protein activity is correlated with regional brain atrophy in AD, we investigated the association between CSF levels of BACE1 and MRI-assessed hippocampus volume in patients with AD (n = 30). An increase in CSF-BACE1 activity was associated with decreased left and right hippocampus volume corrected for global head volume in the AD patients. Boot-strapped regression analysis showed that increased CSF levels of BACE1 activity were associated with increased CSF concentration of total tau but not amyloid-beta1-42 in AD. White matter hyperintensities did not influence the results. BACE1 activity and protein levels were significantly increased in AD compared to 19 elderly healthy controls. Thus, the CSF biomarker candidate of BACE1 activity was associated with hippocampus atrophy in AD in a robust manner and may reflect neurotoxic amyloid-beta-related processes.

  11. An in vivo MR spectroscopy imaging on hippocampus in patients with posttraumatic stress disorder

    International Nuclear Information System (INIS)

    Chen Shulin; Li Lingjiang; Zhang Jinlin; Ma Ning; Gao Xueping; Liu Jun; He Zhong

    2006-01-01

    Objective: To study the characteristic of in vivo MR spectroscopy (MRS) in right and left hippocampal regions of patients with posttraumatic stress disorder (PTSD). Methods: 1 H-MRS was performed on the right and left hippocampal regions in 12 patients with PTSD and 12 normal controls. The peak values of NAA, Cr, and Cho were calculated by Functool software, and the ratios of NAA/Cr and Cho/Cr were compared between PTSD and the control. Results: The NAA/Cr ratio of left hippocampal region in PTSD group was significantly lower than that in the control (F=9.99, P=0.006), but the Cho/Cr ratio in left hippocampal region had no difference between the two groups (F=0.36, P=0.55). Furthermore, the ratios of NAA/Cr and Cho/Cr in right hippocampal region had no significant difference between both groups (F=1.44, P=0.25). Demography factors and the severity of PTSD symptoms were not related to the abnormity of the NAA/Cr ratio of the left hippocampus in PTSD group. Conclusion: The pathological abnormality might exist in the left hippocampus in patients with PTSD, and the NAA/Cr ratio of the left hippocampus was lower than normal. (authors)

  12. Ocimum basilicum improve chronic stress-induced neurodegenerative changes in mice hippocampus.

    Science.gov (United States)

    Ayuob, Nasra Naeim; El Wahab, Manal Galal Abd; Ali, Soad Shaker; Abdel-Tawab, Hanem Saad

    2018-01-22

    Alzheimer's disease (AD), one of the progressive neurodegenerative diseases might be associated with exposure to stress and altered living conditions. This study aimed to evaluate the effectiveness of Ocimum basilicum (OB) essential oils in improving the neurodegenerative-like changes induced in mice after exposed to chronic unpredictable mild stress (CUMS). Forty male Swiss albino mice divided into four groups (n = 10); the control, CUMS, CUMS + Fluoxetine, CUMS + OB were used. Behavioral tests, serum corticosterone level, hippocampus protein level of the glucocorticoid receptors (GRs) and brain-dreived neurotropic factor (BDNF) were determined after exposure to CUMS. Hippocampus was histopathologically examined. Data were analyzed using statistical package for the social sciences (SPSS) and P value of less than 0.05 was considered significant. OB diminished the depression manifestation as well as impaired short term memory observed in the mice after exposure to the CUMS as evidenced by the forced swimming and elevated plus maze test. OB also up-regulated the serum corticosterone level, hippocampal protein level of the glucocorticoid receptor and the brain-derived neurotropic factor and reduced the neurodegenerative and atrophic changes induced in the hippocampus after exposure to CUMS. Essential oils of OB alleviated the memory impairment and hippocampal neurodegenerative changes induced by exposure to the chronic unpredictable stress indicating that it is the time to test its effectiveness on patients suffering from Alzheimer disease.

  13. Deficient plasticity in the hippocampus and the spiral of addiction: focus on adult neurogenesis.

    Science.gov (United States)

    Canales, Juan J

    2013-01-01

    Addiction is a complex neuropsychiatric disorder which causes disruption at multiple levels, including cognitive, emotional, and behavioral domains. Traditional biological theories of addiction have focused on the mesolimbic dopamine pathway and the nucleus accumbens as anatomical substrates mediating addictive-like behaviors. More recently, we have begun to recognize the engagement and dynamic influence of a much broader circuitry which encompasses the frontal cortex, the amygdala, and the hippocampus. In particular, neurogenesis in the adult hippocampus has become a major focus of attention due to its ability to influence memory, motivation, and affect, all of which are disrupted in addiction. First, I summarize toxicological data that reveal strongly suppressive effects of drug exposure on adult hippocampal neurogenesis. Then, I discuss the impact of deficient neurogenesis on learning and memory function, stress responsiveness and affective behavior, as they relate to addiction. Finally, I examine recent behavioral observations that implicate neurogenesis in the adult hippocampus in the emergence and maintenance of addictive behavior. The evidence reviewed here suggests that deficient neurogenesis is associated with several components of the downward spiraling loop that characterizes addiction, including elevated sensitivity to drug-induced reward and reinforcement, enhanced neurohormonal responsiveness, emergence of a negative affective state, memory impairment, and inflexible behavior.

  14. Nicotine disrupts safety learning by enhancing fear associated with a safety cue via the dorsal hippocampus.

    Science.gov (United States)

    Connor, David A; Kutlu, Munir G; Gould, Thomas J

    2017-07-01

    Learned safety, a learning process in which a cue becomes associated with the absence of threat, is disrupted in individuals with post-traumatic stress disorder (PTSD). A bi-directional relationship exists between smoking and PTSD and one potential explanation is that nicotine-associated changes in cognition facilitate PTSD emotional dysregulation by disrupting safety associations. Therefore, we investigated whether nicotine would disrupt learned safety by enhancing fear associated with a safety cue. In the present study, C57BL/6 mice were administered acute or chronic nicotine and trained over three days in a differential backward trace conditioning paradigm consisting of five trials of a forward conditioned stimulus (CS)+ (Light) co-terminating with a footshock unconditioned stimulus followed by a backward CS- (Tone) presented 20 s after cessation of the unconditioned stimulus. Summation testing found that acute nicotine disrupted learned safety, but chronic nicotine had no effect. Another group of animals administered acute nicotine showed fear when presented with the backward CS (Light) alone, indicating the formation of a maladaptive fear association with the backward CS. Finally, we investigated the brain regions involved by administering nicotine directly into the dorsal hippocampus, ventral hippocampus, and prelimbic cortex. Infusion of nicotine into the dorsal hippocampus disrupted safety learning.

  15. Proliferating neuronal progenitors in the postnatal hippocampus transiently express the proneural gene Ngn2.

    Science.gov (United States)

    Ozen, Ilknur; Galichet, Christophe; Watts, Colin; Parras, Carlos; Guillemot, François; Raineteau, Olivier

    2007-05-01

    Little is known of the transcription factors expressed by adult neural progenitors produced in the hippocampal neurogenic niche. Here, we study the expression of the proneural basic helix-loop-helix (bHLH) transcription factor Neurogenin-2 (Ngn2) in the adult hippocampus. We have characterized the pattern of expression of Ngn2 in the adult hippocampus using immunostaining for Ngn2 protein and a Ngn2-green fluorescent protein (GFP) reporter mouse strain. A significant proportion of Ngn2-expressing cells were mitotically active. Ngn2-GFP expression was restricted to the subgranular zone and declined with age. Neuronal markers were used to determine the phenotype of Ngn2-expressing cells. The vast majority of Ngn2-GFP-positive cells expressed the immature neuronal markers, doublecortin (DCX) and polysialic acid-neural cell adhesion molecule (PSA-NCAM). Finally, the pattern of Ngn2 expression was studied following seizure induction. Our data show an increase in neurogenesis, detected in these animals by bromodeoxyuridine (BrdU) and DCX staining that was contemporaneous with a marked increase in Ngn2-GFP-expression. Taken together, our results show that Ngn2-GFP represents a specific marker for neurogenesis and its modulation in the adult hippocampus. Ngn2 transient expression in proliferating neuronal progenitors supports the idea that it plays a significant role in adult neurogenesis.

  16. Urtica dioica leaves modulates muscarinic cholinergic system in the hippocampus of streptozotocin-induced diabetic mice.

    Science.gov (United States)

    Patel, Sita Sharan; Parashar, Arun; Udayabanu, Malairaman

    2015-06-01

    Diabetes mellitus is a chronic metabolic disorder and has been associated with cognitive dysfunction. In our earlier study, chronic Urtica dioica (UD) treatment significantly ameliorated diabetes induced associative and spatial memory deficit in mice. The present study was designed to explore the effect of UD leaves extract on muscarinic cholinergic system, which has long been known to be involved in cognition. Streptozotocin (STZ) (50 mg/kg, i.p., consecutively for 5 days) was used to induce diabetes followed by treatment with UD extract (50 mg/kg, oral) or rosiglitazone (5 mg/kg, oral) for 8 weeks. STZ-induced diabetic mice showed significant reduction in hippocampal muscarinic acetylcholine receptor-1 and choline acetyltransferase expressions. Chronic diabetes significantly up-regulated the protein expression of acetylcholinesterase associated with oxidative stress in hippocampus. Besides, STZ-induced diabetic mice showed hypolocomotion with up-regulation of muscarinic acetylcholine receptor-4 expression in striatum. Chronic UD treatment significantly attenuated the cholinergic dysfunction and oxidative stress in the hippocampus of diabetic mice. UD had no effect on locomotor activity and muscarinic acetylcholine receptor-4 expression in striatum. In conclusion, UD leaves extract has potential to reverse diabetes mediated alteration in muscarinic cholinergic system in hippocampus and thereby improve memory functions.

  17. The effects of neonatal amygdala or hippocampus lesions on adult social behavior.

    Science.gov (United States)

    Bliss-Moreau, Eliza; Moadab, Gilda; Santistevan, Anthony; Amaral, David G

    2017-03-30

    The present report details the final phase of a longitudinal evaluation of the social behavior in a cohort of adult rhesus monkeys that received bilateral neurotoxic lesions of the amygdala or hippocampus, or sham operations at 2 weeks of age. Results were compared to previous studies in which adult animals received amygdala lesions and were tested in a similar fashion. Social testing with four novel interaction partners occurred when the animals were between 7 and 8 years of age. Experimental animals interacted with two male and two female partners in two conditions - one in which physical access was restricted (the constrained social access condition) and a second in which physical access was unrestricted (the unconstrained social access condition). Across conditions and interaction partners, there were no significant effects of lesion condition on the frequency or duration of social interactions. As a group, the hippocampus-lesioned animals generated the greatest number of communicative signals during the constrained social access condition. Amygdala-lesioned animals generated more frequent stress-related behaviors and were less exploratory. Amygdala and hippocampus-lesioned animals demonstrated greater numbers of stereotypies than control animals. Subtle, lesion-based differences in the sequencing of behaviors were observed. These findings suggest that alterations of adult social behavior are much less prominent when damage to the amygdala occurs early in life rather than in adulthood. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Spatial olfactory learning facilitates long-term depression in the hippocampus.

    Science.gov (United States)

    André, Marion Agnès Emma; Manahan-Vaughan, Denise

    2013-10-01

    Recently, it has emerged that visual spatial exploration facilitates synaptic plasticity at different synapses within the trisynaptic network. Particularly striking is the finding that visuospatial contexts facilitate hippocampal long-term depression (LTD), raising the possibility that this form of plasticity may be important for memory formation. It is not known whether other sensory modalities elicit similar permissive effects on LTD. Here, we explored if spatial olfactory learning facilitates LTD in the hippocampus region of freely behaving rats. Patterned afferent stimulation of the Schaffer collaterals elicited short-term depression (STD) (<1 h) of evoked responses in the Stratum radiatum of the CA1 region. Coupling of this protocol with novel exploration of a spatial constellation of olfactory cues facilitated short-term depression into LTD that lasted for over 24 h. Facilitation of LTD did not occur when animals were re-exposed 1 week later to the same odors in the same spatial constellation. Evaluation of learning behavior revealed that 1 week after the 1st odor exposure, the animals remembered the odors and their relative positions. These data support that the hippocampus can use nonvisuospatial resources, and specifically can use spatial olfactory information, to facilitate LTD and to generate spatial representations. The data also support that a tight relationship exists between the processing of spatial contextual information and the expression of LTD in the hippocampus. Copyright © 2013 Wiley Periodicals, Inc.

  19. Antioxidant effects of nerolidol in mice hippocampus after open field test.

    Science.gov (United States)

    Nogueira Neto, José Damasceno; de Almeida, Antonia Amanda Cardoso; da Silva Oliveira, Johanssy; Dos Santos, Pauline Sousa; de Sousa, Damião Pergentino; de Freitas, Rivelilson Mendes

    2013-09-01

    The aim of this study was to evaluate the neuroprotective effects of nerolidol in mice hippocampus against oxidative stress in neuronal cells compared to ascorbic acid (positive control) as well as evaluated the nerolidol sedative effects by open field test compared to diazepam (positive control). Thirty minutes prior to behavioral observation on open field test, mice were intraperitoneally treated with vehicle, nerolidol (25, 50 and 75 mg/kg), diazepam (1 mg/kg) or ascorbic acid (250 mg/kg). To clarify the action mechanism of of nerolidol on oxidative stress in animals subjected to the open field test, Western blot analysis of Mn-superoxide dismutase and catalase in mice hippocampus were performed. In nerolidol group, there was a significant decrease in lipid peroxidation and nitrite levels when compared to negative control (vehicle). However, a significant increase was observed in superoxide dismutase and catalase activities in this group when compared to the other groups. Vehicle, diazepam, ascorbic acid and nerolidol groups did not affected Mn-superoxide dismutase, catalase mRNA or protein levels. Our findings strongly support the hypothesis that oxidative stress occurs in hippocampus. Nerolidol showed sedative effects in animals subjected to the open field test. Oxidative process plays a crucial role on neuronal pathological consequence, and implies that antioxidant effects could be achieved using this sesquiterpene.

  20. Effect of tibolone on dendritic spine density in the rat hippocampus.

    Science.gov (United States)

    Beltrán-Campos, V; Díaz-Ruiz, A; Padilla-Gómez, E; Aguilar Zavala, H; Ríos, C; Díaz Cintra, S

    2015-09-01

    Oestrogen deficiency produces oxidative stress (OS) and changes in hippocampal neurons and also reduces the density of dendritic spines (DS). These alterations affect the plastic response of the hippocampus. Oestrogen replacement therapy reverses these effects, but it remains to be seen whether the same changes are produced by tibolone (TB). The aim of this study was to test the neuroprotective effects of long-term oral TB treatment and its ability to reverse DS pruning in pyramidal neurons (PN) of hippocampal area CA1. Young Sprague Dawley rats were distributed in 3 groups: a control group in proestrus (Pro) and two ovariectomised groups (Ovx), of which one was provided with a daily TB dose (1mg/kg), OvxTB and the other with vehicle (OvxV), for 40 days in both cases. We analysed lipid peroxidation and DS density in 3 segments of apical dendrites from PNs in hippocampal area CA1. TB did not reduce lipid peroxidation but it did reverse the spine pruning in CA1 pyramidal neurons of the hippocampus which had been caused by ovariectomy. Oestrogen replacement therapy for ovariectomy-induced oestrogen deficiency has a protective effect on synaptic plasticity in the hippocampus. Copyright © 2014 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.

  1. Immunoreactivity of S100β protein in the hippocampus of chinchilla

    Directory of Open Access Journals (Sweden)

    Krawczyk Aleksandra

    2014-03-01

    Full Text Available The aim of the study was to investigate S100β protein in astrocytes of CA1 and CA3 areas of the hippocampus proper and the dentate gyrus with the hilus yet undefined in mature males of chinchilla. The presence of S100β was determined using indirect immunohistochemical peroxidase-antiperoxidase method with specific monoclonal antibody against this protein. Most of the S100β-positive cells were detected in the subgranular zone of the dentate gyrus and in the middle part of the hilus. In CA3 area, it was found that the most numerous cells with S100β are in stratum radiatum. In CA1 area, there were single astrocytes expressing this protein. This data demonstrates species differences and a large quantity of S100β immunoreactive cells in the subgranular zone of the dentate gyrus of chinchilla, which may be associated with structural reorganisation of the hippocampus and with neurogenesis, learning, and memorising process dependent on the hippocampus.

  2. Virtual water maze learning in human increases functional connectivity between posterior hippocampus and dorsal caudate.

    Science.gov (United States)

    Woolley, Daniel G; Mantini, Dante; Coxon, James P; D'Hooge, Rudi; Swinnen, Stephan P; Wenderoth, Nicole

    2015-04-01

    Recent work has demonstrated that functional connectivity between remote brain regions can be modulated by task learning or the performance of an already well-learned task. Here, we investigated the extent to which initial learning and stable performance of a spatial navigation task modulates functional connectivity between subregions of hippocampus and striatum. Subjects actively navigated through a virtual water maze environment and used visual cues to learn the position of a fixed spatial location. Resting-state functional magnetic resonance imaging scans were collected before and after virtual water maze navigation in two scan sessions conducted 1 week apart, with a behavior-only training session in between. There was a large significant reduction in the time taken to intercept the target location during scan session 1 and a small significant reduction during the behavior-only training session. No further reduction was observed during scan session 2. This indicates that scan session 1 represented initial learning and scan session 2 represented stable performance. We observed an increase in functional connectivity between left posterior hippocampus and left dorsal caudate that was specific to scan session 1. Importantly, the magnitude of the increase in functional connectivity was correlated with offline gains in task performance. Our findings suggest cooperative interaction occurs between posterior hippocampus and dorsal caudate during awake rest following the initial phase of spatial navigation learning. Furthermore, we speculate that the increase in functional connectivity observed during awake rest after initial learning might reflect consolidation-related processing. © 2014 Wiley Periodicals, Inc.

  3. Humor Appreciation Involves Parametric and Synchronized Activity in the Medial Prefrontal Cortex and Hippocampus.

    Science.gov (United States)

    Iidaka, Tetsuya

    2017-12-01

    Humor perception is a ubiquitous phenomenon in human societies. In theories of humor perception, three factors, non-seriousness, social context, and incongruity, have been implicated in humor. In another theory, however, elaboration and reinterpretation of contexts are considered to play a role in eliciting humor. Although the neural correlates of humor appreciation have been investigated using neuroimaging methods, only a few studies have conducted such experiments under natural conditions. In the present study, two functional magnetic resonance imaging experiments, using a comedy movie as a stimulus, were conducted to investigate the neural correlates of humor under natural conditions. The subjects' brain activity was measured while watching and enjoying a movie. In experiment 1, a parametric analysis showed that the medial prefrontal cortex (MPFC) and hippocampus/amygdala had a positive relationship with the subjective rating of funniness. In experiment 2, intersubject correlation was analyzed to investigate synchronized activity across all participants. Signal synchronization that paralleled increased funniness ratings was observed in the MPFC and hippocampus. Thus, it appears that both parametric and synchronized activity in the MPFC and hippocampus are important during humor appreciation. The present study has revealed the brain regions that are predominantly involved in humor sensation under natural condition. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. Response of extracellular zinc in the ventral hippocampus against novelty stress.

    Science.gov (United States)

    Takeda, Atsushi; Sakurada, Naomi; Kanno, Shingo; Minami, Akira; Oku, Naoto

    2006-10-01

    An extensive neuronal activity takes place in the hippocampus during exploratory behavior. However, the role of hippocampal zinc in exploratory behavior is poorly understood. To analyze the response of extracellular zinc in the hippocampus against novelty stress, rats were placed for 50 min in a novel environment once a day for 8 days. Extracellular glutamate in the hippocampus was increased during exploratory behavior on day 1, whereas extracellular zinc was decreased. The same phenomenon was observed during exploratory behavior on day 2 and extracellular zinc had returned to the basal level during exploratory behavior on day 8. To examine the significance of the decrease in extracellular zinc in exploratory activity, exploratory behavior was observed during perfusion with 1 mm CaEDTA, a membrane-impermeable zinc chelator. Locomotor activity in the novel environment was decreased by perfusion with CaEDTA. The decrease in extracellular zinc and the increase in extracellular glutamate in exploratory period were abolished by perfusion with CaEDTA. These results suggest that zinc uptake by hippocampal cells is linked to exploratory activity and is required for the activation of the glutamatergic neurotransmitter system. The zinc uptake may be involved in the response to painless psychological stress or in the cognitive processes.

  5. Effect of hindlimb unloading on stereological parameters of the motor cortex and hippocampus in male rats.

    Science.gov (United States)

    Salehi, Mohammad Saied; Mirzaii-Dizgah, Iraj; Vasaghi-Gharamaleki, Behnoosh; Zamiri, Mohammad Javad

    2016-11-09

    Hindlimb unloading (HU) can cause motion and cognition dysfunction, although its cellular and molecular mechanisms are not well understood. The aim of the present study was to determine the stereological parameters of the brain areas involved in motion (motor cortex) and spatial learning - memory (hippocampus) under an HU condition. Sixteen adult male rats, kept under a 12 : 12 h light-dark cycle, were divided into two groups of freely moving (n=8) and HU (n=8) rats. The volume of motor cortex and hippocampus, the numerical cell density of neurons in layers I, II-III, V, and VI of the motor cortex, the entire motor cortex as well as the primary motor cortex, and the numerical density of the CA1, CA3, and dentate gyrus subregions of the hippocampus were estimated. No significant differences were observed in the evaluated parameters. Our results thus indicated that motor cortical and hippocampal atrophy and cell loss may not necessarily be involved in the motion and spatial learning memory impairment in the rat.

  6. Granule cell potentials in the dentate gyrus of the hippocampus: coping behavior and stress ulcers in rats.

    Science.gov (United States)

    Henke, P G

    1990-01-01

    Evoked population potentials of the granule cells in the dentate gyrus of the hippocampus were increased in stress-resistant rats and decreased in stress-susceptible rats, as indexed by restraint-induced gastric ulcers. Inescapable, uncontrollable shock stimulation also suppressed granule cell population spikes and interfered with subsequent coping responses when escape was possible, i.e. the so-called helplessness effect. The data were interpreted to indicate that the hippocampus is part of a coping system in stressful situations.

  7. Disrupted functional connectivity of the hippocampus in patients with hyperthyroidism: Evidence from resting-state fMRI

    International Nuclear Information System (INIS)

    Zhang, Wei; Liu, Xianjun; Zhang, Yi; Song, Lingheng; Hou, Jingming; Chen, Bing; He, Mei; Cai, Ping; Lii, Haitao

    2014-01-01

    Objective: The hippocampus expresses high levels of thyroid hormone receptors, suggesting that hippocampal functions, including cognition and regulation of mood, can be disrupted by thyroid pathology. Indeed, structural and functional alterations within the hippocampus have been observed in hyperthyroid patients. In addition to internal circuitry, hippocampal processing is dependent on extensive connections with other limbic and neocortical structures, but the effects of hyperthyroidism on functional connectivity (FC) with these areas have not been studied. The purpose of this study was to investigate possible abnormalities in the FC between the hippocampus and other neural structures in hyperthyroid patients using resting-state fMRI. Methods: Seed-based correlation analysis was performed on resting-state fMRI data to reveal possible differences in hippocampal FC between hyperthyroid patients and healthy controls. Correlation analysis was used to investigate the relationships between the strength of FC in regions showing significant group differences and clinical variables. Results: Compared to controls, hyperthyroid patients showed weaker FC between the bilateral hippocampus and both the bilateral anterior cingulate cortex (ACC) and bilateral posterior cingulate cortex (PCC), as well as between the right hippocampus and right medial orbitofrontal cortex (mOFC). Disease duration was negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC and PCC. Levels of depression and anxiety were negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC. Conclusion: Decreased functional connectivity between the hippocampus and bilateral ACC, PCC, and right mOFC may contribute to the emotional and cognitive dysfunction associated with hyperthyroidism

  8. Role of the thalamic nucleus reuniens in mediating interactions between the hippocampus and medial prefrontal cortex during spatial working memory

    Directory of Open Access Journals (Sweden)

    Amy L Griffin

    2015-03-01

    Full Text Available Despite decades of research, the neural mechanisms of spatial working memory remain poorly understood. Although the dorsal hippocampus is known to be critical for memory-guided behavior, experimental evidence suggests that spatial working memory depends not only on the hippocampus itself, but also on the circuit comprised of the hippocampus and the medial prefrontal cortex (mPFC. Disruption of hippocampal-mPFC interactions may result in failed transfer of spatial and contextual information processed by the hippocampus to the circuitry in mPFC responsible for decision making and goal-directed behavior. Oscillatory synchrony between the hippocampus and mPFC has been shown to increase in tasks with high spatial working memory demand. However, the mechanisms and circuitry supporting hippocampal-mPFC interactions during these tasks is unknown. The midline thalamic nucleus reuniens (RE is reciprocally connected to both the hippocampus and the mPFC and has been shown to be critical for a variety of working memory tasks. Therefore, it is likely that hippocampal-mPFC oscillatory synchrony is modulated by RE activity. This article will review the anatomical connections between the hippocampus, mPFC and RE along with the behavioral studies that have investigated the effects of RE disruption on working memory task performance. The article will conclude with suggestions for future directions aimed at identifying the specific role of the RE in regulating functional interactions between the hippocampus and the PFC and investigating the degree to which these interactions contribute to spatial working memory.

  9. HDAC inhibition modulates hippocampus-dependent long-term memory for object location in a CBP-dependent manner

    Science.gov (United States)

    Haettig, Jakob; Stefanko, Daniel P.; Multani, Monica L.; Figueroa, Dario X.; McQuown, Susan C.; Wood, Marcelo A.

    2011-01-01

    Transcription of genes required for long-term memory not only involves transcription factors, but also enzymatic protein complexes that modify chromatin structure. Chromatin-modifying enzymes, such as the histone acetyltransferase (HAT) CREB (cyclic-AMP response element binding) binding protein (CBP), are pivotal for the transcriptional regulation required for long-term memory. Several studies have shown that CBP and histone acetylation are necessary for hippocampus-dependent long-term memory and hippocampal long-term potentiation (LTP). Importantly, every genetically modified Cbp mutant mouse exhibits long-term memory impairments in object recognition. However, the role of the hippocampus in object recognition is controversial. To better understand how chromatin-modifying enzymes modulate long-term memory for object recognition, we first examined the role of the hippocampus in retrieval of long-term memory for object recognition or object location. Muscimol inactivation of the dorsal hippocampus prior to retrieval had no effect on long-term memory for object recognition, but completely blocked long-term memory for object location. This was consistent with experiments showing that muscimol inactivation of the hippocampus had no effect on long-term memory for the object itself, supporting the idea that the hippocampus encodes spatial information about an object (such as location or context), whereas cortical areas (such as the perirhinal or insular cortex) encode information about the object itself. Using location-dependent object recognition tasks that engage the hippocampus, we demonstrate that CBP is essential for the modulation of long-term memory via HDAC inhibition. Together, these results indicate that HDAC inhibition modulates memory in the hippocampus via CBP and that different brain regions utilize different chromatin-modifying enzymes to regulate learning and memory. PMID:21224411

  10. Disrupted functional connectivity of the hippocampus in patients with hyperthyroidism: Evidence from resting-state fMRI

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei, E-mail: will.zhang.1111@gmail.com [Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Department of Radiology, Sichuan Provincial Corps Hospital, Chinese People' s Armed Police Forces, Leshan 614000 (China); Liu, Xianjun, E-mail: xianjun6.liu@gmail.com [Department of Radiology, Sichuan Provincial Corps Hospital, Chinese People' s Armed Police Forces, Leshan 614000 (China); Zhang, Yi, E-mail: yi.zhang.0833@gmail.com [Department of Radiology, Sichuan Provincial Corps Hospital, Chinese People' s Armed Police Forces, Leshan 614000 (China); Song, Lingheng, E-mail: songlh1023@hotmail.com [Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Hou, Jingming, E-mail: jingminghou@hotmail.com [Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Chen, Bing, E-mail: chenbing3@medmail.com.cn [Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); He, Mei, E-mail: sunnusunny0105@gmail.com [Department of Clinical Psychology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Cai, Ping, E-mail: pingc_ddd@sina.com [Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Lii, Haitao, E-mail: haitaolii023@gmail.com [Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China)

    2014-10-15

    Objective: The hippocampus expresses high levels of thyroid hormone receptors, suggesting that hippocampal functions, including cognition and regulation of mood, can be disrupted by thyroid pathology. Indeed, structural and functional alterations within the hippocampus have been observed in hyperthyroid patients. In addition to internal circuitry, hippocampal processing is dependent on extensive connections with other limbic and neocortical structures, but the effects of hyperthyroidism on functional connectivity (FC) with these areas have not been studied. The purpose of this study was to investigate possible abnormalities in the FC between the hippocampus and other neural structures in hyperthyroid patients using resting-state fMRI. Methods: Seed-based correlation analysis was performed on resting-state fMRI data to reveal possible differences in hippocampal FC between hyperthyroid patients and healthy controls. Correlation analysis was used to investigate the relationships between the strength of FC in regions showing significant group differences and clinical variables. Results: Compared to controls, hyperthyroid patients showed weaker FC between the bilateral hippocampus and both the bilateral anterior cingulate cortex (ACC) and bilateral posterior cingulate cortex (PCC), as well as between the right hippocampus and right medial orbitofrontal cortex (mOFC). Disease duration was negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC and PCC. Levels of depression and anxiety were negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC. Conclusion: Decreased functional connectivity between the hippocampus and bilateral ACC, PCC, and right mOFC may contribute to the emotional and cognitive dysfunction associated with hyperthyroidism.

  11. Anterior/posterior competitive deactivation/activation dichotomy in the human hippocampus as revealed by a 3D navigation task.

    Directory of Open Access Journals (Sweden)

    Isabel Catarina Duarte

    Full Text Available Anterior/posterior long axis specialization is thought to underlie the organization of the hippocampus. However it remains unclear whether antagonistic mechanisms differentially modulate processing of spatial information within the hippocampus. We used fMRI and a virtual reality 3D paradigm to study encoding and retrieval of spatial memory during active visuospatial navigation, requiring positional encoding and retrieval of object landmarks during the path. Both encoding and retrieval elicited BOLD activation of the posterior most portion of hippocampus, while concurrent deactivations (recently shown to reflect decreases in neural responses were found in the most anterior regions. Encoding elicited stronger activity in the posterior right than the left hippocampus. The former structure also showed significantly stronger activity for allocentric vs. egocentric processing during retrieval. The anterior vs. posterior pattern mimics, from a functional point, although at much distinct temporal scales, the previous anatomical findings in London taxi drivers, whereby posterior enlargement was found at the cost of an anterior decrease, and the mirror symmetric findings observed in blind people, in whom the right anterior hippocampus was found to be larger, at the cost of a smaller posterior hippocampus, as compared with sighted people. In sum, we found a functional dichotomy whereby the anterior/posterior hippocampus shows antagonistic processing patterns for spatial encoding and retrieval of 3D spatial information. To our knowledge, this is the first study reporting such a dynamical pattern in a functional study, which suggests that differential modulation of neural responses within the human hippocampus reflects distinct roles in spatial memory processing.

  12. Disrupted functional connectivity of the hippocampus in patients with hyperthyroidism: evidence from resting-state fMRI.

    Science.gov (United States)

    Zhang, Wei; Liu, Xianjun; Zhang, Yi; Song, Lingheng; Hou, Jingming; Chen, Bing; He, Mei; Cai, Ping; Lii, Haitao

    2014-10-01

    The hippocampus expresses high levels of thyroid hormone receptors, suggesting that hippocampal functions, including cognition and regulation of mood, can be disrupted by thyroid pathology. Indeed, structural and functional alterations within the hippocampus have been observed in hyperthyroid patients. In addition to internal circuitry, hippocampal processing is dependent on extensive connections with other limbic and neocortical structures, but the effects of hyperthyroidism on functional connectivity (FC) with these areas have not been studied. The purpose of this study was to investigate possible abnormalities in the FC between the hippocampus and other neural structures in hyperthyroid patients using resting-state fMRI. Seed-based correlation analysis was performed on resting-state fMRI data to reveal possible differences in hippocampal FC between hyperthyroid patients and healthy controls. Correlation analysis was used to investigate the relationships between the strength of FC in regions showing significant group differences and clinical variables. Compared to controls, hyperthyroid patients showed weaker FC between the bilateral hippocampus and both the bilateral anterior cingulate cortex (ACC) and bilateral posterior cingulate cortex (PCC), as well as between the right hippocampus and right medial orbitofrontal cortex (mOFC). Disease duration was negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC and PCC. Levels of depression and anxiety were negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC. Decreased functional connectivity between the hippocampus and bilateral ACC, PCC, and right mOFC may contribute to the emotional and cognitive dysfunction associated with hyperthyroidism. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Volumetric and morphological characteristics of the hippocampus are associated with progression to schizophrenia in patients with first-episode psychosis.

    Science.gov (United States)

    Sauras, R; Keymer, A; Alonso-Solis, A; Díaz, A; Molins, C; Nuñez, F; Rabella, M; Roldán, A; Grasa, E; Alvarez, E; Portella, M J; Corripio, I

    2017-09-01

    Abnormalities in the hippocampus have been implicated in the pathophysiology of psychosis. However, it is still unclear whether certain abnormalities are a pre-existing vulnerability factor, a sign of disease progression or a consequence of environmental factors. We hypothesized that first-episode psychosis patients who progress to schizophrenia after one year of follow up will display greater volumetric and morphological changes from the very beginning of the disorder. We studied the hippocampus of 41 patients with a first-episode psychosis and 41 matched healthy controls. MRI was performed at the time of the inclusion in the study. After one year, the whole sample was reevaluated and divided in two groups depending on the diagnoses (schizophrenia vs. non-schizophrenia). Patients who progressed to schizophrenia showed a significantly smaller left hippocampus volume than control group and no-schizophrenia group (F=3.54; df=2, 77; P=0.03). We also found significant differences in the morphology of the anterior hippocampus (CA1) of patients with first-episode psychosis who developed schizophrenia compared with patients who did not. These results are consistent with the assumption of hyperfunctioning dopaminergic cortico-subcortical circuits in schizophrenia, which might be related with an alteration of subcortical structures, such as the hippocampus, along the course of the disease. According with these results, hippocampus abnormalities may serve as a prognostic marker of clinical outcome in patients with a first-episode psychosis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Chronic traumatic stress impairs memory in mice: Potential roles of acetylcholine, neuroinflammation and corticotropin releasing factor expression in the hippocampus.

    Science.gov (United States)

    Bhakta, Ami; Gavini, Kartheek; Yang, Euitaek; Lyman-Henley, Lani; Parameshwaran, Kodeeswaran

    2017-09-29

    Chronic stress in humans can result in multiple adverse psychiatric and neurobiological outcomes, including memory deficits. These adverse outcomes can be more severe if each episode of stress is very traumatic. When compared to acute or short term stress relatively little is known about the effects of chronic traumatic stress on memory and molecular changes in hippocampus, a brain area involved in memory processing. Here we studied the effects of chronic traumatic stress in mice by exposing them to adult Long Evan rats for 28 consecutive days and subsequently analyzing behavioral outcomes and the changes in the hippocampus. Results show that stressed mice developed memory deficits when assayed with radial arm maze tasks. However, chronic traumatic stress did not induce anxiety, locomotor hyperactivity or anhedonia. In the hippocampus of stressed mice interleukin-1β protein expression was increased along with decreased corticotropin releasing hormone (CRH) gene expression. Furthermore, there was a reduction in acetylcholine levels in the hippocampus of stressed mice. There were no changes in brain derived neurotrophic factor (BDNF) or nerve growth factor (NGF) levels in the hippocampus of stressed mice. Gene expression of immediate early genes (Zif268, Arc, C-Fos) as well as glucocorticoid and mineralocorticoid receptors were also not affected by chronic stress. These data demonstrate that chronic traumatic stress followed by a recovery period might lead to development of resilience resulting in the development of selected, most vulnerable behavioral alterations and molecular changes in the hippocampus. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Functional contributions and interactions between the human hippocampus and subregions of the striatum during arbitrary associative learning and memory

    Science.gov (United States)

    Mattfeld, Aaron T.; Stark, Craig E. L.

    2015-01-01

    The hippocampus and striatum are thought to have different functional roles in learning and memory. It is unknown under what experimental conditions their contributions are dissimilar or converge, and the extent to which they interact over the course of learning. In order to evaluate both the functional contributions of as well as the interactions between the human hippocampus and striatum, the present study used high-resolution functional magnetic resonance imaging (fMRI) and variations of a conditional visuomotor associative learning task that either taxed arbitrary associative learning (Experiment 1) or stimulus-response learning (Experiment 2). In the first experiment we observed changes in activity in the hippocampus and anterior caudate that reflect differences between the two regions consistent with distinct computational principles. In the second experiment we observed activity in the putamen that reflected content specific representations during the learning of arbitrary conditional visuomotor associations. In both experiments the hippocampus and ventral striatum demonstrated dynamic functional coupling during the learning of new arbitrary associations, but not during retrieval of well-learned arbitrary associations using control variants of the tasks that did not preferentially tax one system versus the other. These findings suggest that both the hippocampus and subregions of the dorsal striatum contribute uniquely to the learning of arbitrary associations while the hippocampus and ventral striatum interact over the course of learning. PMID:25560298

  16. [Effect of electromagnetic radiation on discharge activity of neurons in the hippocampus CA1 in rats].

    Science.gov (United States)

    Tong, Jun; Chen, Su; Liu, Xiang-Ming; Hao, Dong-Mei

    2013-09-01

    In order to explore effect of electromagnetic radiation on learning and memory ability of hippocampus neuron in rats, the changes in discharge patterns and overall electrical activity of hippocampus neuron after electromagnetic radiation were observed. Rat neurons discharge was recorded with glass electrode extracellular recording technology and a polygraph respectively. Radiation frequency of electromagnetic wave was 900 MHZ and the power was 10 W/m2. In glass electrode extracellular recording, the rats were separately irradiated for 10, 20, 30, 40, 50 and 60 min, every points repeated 10 times and updated interval of 1h, observing the changes in neuron discharge and spontaneous discharge patterns after electromagnetic radiation. In polygraph recording experiments, irradiation group rats for five days a week, 6 hours per day, repeatedly for 10 weeks, memory electrical changes in control group and irradiation group rats when they were feeding were repeatedly monitored by the implanted electrodes, observing the changes in peak electric digits and the largest amplitude in hippocampal CA1 area, and taking some electromagnetic radiation sampling sequence for correlation analysis. (1) Electromagnetic radiation had an inhibitory role on discharge frequency of the hippocampus CA1 region neurons. After electromagnetic radiation, discharge frequency of the hippocampus CA1 region neurons was reduced, but the changes in scale was not obvious. (2) Electromagnetic radiation might change the spontaneous discharge patterns of hippocampus CA1 region neurons, which made the explosive discharge pattern increased obviously. (3) Peak potential total number within 5 min in irradiation group was significantly reduced, the largest amplitude was less than that of control group. (4) Using mathematical method to make the correlation analysis of the electromagnetic radiation sampling sequence, that of irradiation group was less than that of control group, indicating that there was a tending

  17. METALS IN THE METABOLISM OF HIPPOCAMPUS AND ROLE OF ZINC IN THE PATHOGENESIS OF EPILEPTIC SEIZURES

    Directory of Open Access Journals (Sweden)

    O. M. Kuchkovsky

    2016-05-01

    Full Text Available Physiological mechanisms of convulsions status during epilepsy or episindrom significantly different from the mechanisms, which were describe for other disorders associated with glutamatergic system, such as schizophrenia (a decrease of glutamate in neurons and increased dopaminergic load, drug addiction and alcoholism (the formation of endogenous opioids and dopamine, strengthening the role of GABA-ergic system. With glutamatergic transmission are сconnect not only convulsive state, but also the realization of higher integrative functions. Therefore, the development of epilepsy, particularly  which caused glutamate, implemented by activating Zn-ergic hippocampal neurons, associate with complex changes in human mental functions. Based on a scientific literature about  of the role of chelating zinc in the mechanisms of glutamatergic transmission, we can  suggest it participation in the mechanisms of formation of epilepsy  convulsions. In experience on animals, was show that in the animal organism of stressing correlative changes observe zinc content and secretory material in the hippocampus, Paneth cells  and B cells of pancreas. The nature of the changes depend on the stressor. When this change of zinc content in the hippocampus and hypothalamus (as the main regulator of stress reaction were multidirectional that this can be explained by the release of metal together with secretory material in the hypothalamus into the bloodstream. Research epileptic activity  of hippocampus by administering to the animal chelate 8 BSQ allowed to establish the dependence between convulsant action  and first  stress condition of the animal. Evocation of stress by 8-BSQ and physical activity, immobilization and alcohol abuse found that the convulsive effect of this reagent during intravitreal research increased in the case of prior exposure by specified kinds of stressors. In this pre-convulsive effect on exertion increased by 266% and the zinc content

  18. Studies of the macroscopic and microscopic morphology (hippocampus of brain in Vencobb broiler

    Directory of Open Access Journals (Sweden)

    Shailesh Kumar Gupta

    2016-05-01

    Full Text Available Aim: The aim of this study was to study the anatomy of different parts of brain and histology of hippocampus of Vencobb broiler chicken. Materials and Methods: A 12 adult experimental birds were sacrificed by cervical dislocation. After separation of the brain, gross anatomy features were studied. Brain tissue was fixed in 10% buffered neutral formalin for 2-3 days, and then routine dehydration process in ascending grades of ethyl alcohol was done. After xylene cleaning, paraffin impregnation was prepared. Paraffin blocks were cut, and slides were stained by Harris hematoxylin and eosin. Photography was carried out both under lower (×10 and higher (×40 magnifications. Results: The brain structure (dorsal view of Vencobb bird resembled the outline of a playing card symbol of a “spade.” The brain subdivisions are cerebrum, cerebellum, and medulla oblongata. Cerebrum was devoid of usual convolutions (elevations, gyri, depressions (grooves, and sulci. The cerebral hemispheres were tightly apposed along a median sulcus called interhemispheric fissure and cerebrum and cerebellum were separated by a small transverse fissure. The olfactory bulb was small structures, and the pineal body was clearly visible. The optic lobes were partially hidden under cerebral hemispheres, but laterally, it was large, prominent rounded or spherical bodies of the midbrain. The hippocampal area appeared as dorso-medial protrusion. Different types of neurons were distinguished in the hippocampus were pyramidal neurons, pyramidal-like neurons, and multipolar neurons, etc. There was rich vascularization in the form of blood capillaries throughout the hippocampus. Conclusion: Cerebrum was pear shaped and largest part of the brain. Cerebrum hemisphere was smooth devoid of convolutions, gyri, and depressions, but in the surface of cerebellum, there was the presence of a number of transverse depression (grooves and sulci subdividing into many folds. Olfactory bulb was poorly

  19. Perinatal exposure to lead induces morphological, ultrastructural and molecular alterations in the hippocampus

    International Nuclear Information System (INIS)

    Baranowska-Bosiacka, I.; Strużyńska, L.; Gutowska, I.; Machalińska, A.; Kolasa, A.; Kłos, P.; Czapski, G.A.; Kurzawski, M.; Prokopowicz, A.; Marchlewicz, M.

    2013-01-01

    Highlights: ► Pre- and neonatal Pb exposure decreased the number of hippocampal neurons. ► Lead caused ultrastructural alterations in CA1 region of hippocampus. ► Hippocampus is highly vulnerable to low level perinatal Pb exposure. ► Lead decreased BDNF level in the developing brain. ► Decreased Bax/Bcl2 ratio may protect hippocampus against Pb-induced apoptosis. -- Abstract: The aim of this paper is to examine if pre- and neonatal exposure to lead (Pb) may intensify or inhibit apoptosis or necroptosis in the developing rat brain. Pregnant experimental females received 0.1% lead acetate (PbAc) in drinking water from the first day of gestation until weaning of the offspring; the control group received distilled water. During the feeding of pups, mothers from the experimental group were still receiving PbAc. Pups were weaned at postnatal day 21 and the young rats of both groups then received only distilled water until postnatal day 28. This treatment protocol resulted in a concentration of Pb in rat offspring whole blood (Pb-B) below the threshold of 10 μg/dL, considered safe for humans.We studied Casp-3 activity and expression, AIF nuclear translocation, DNA fragmentation, as well as Bax, Bcl-2 mRNA and protein expression as well as BDNF concentration in selected structures of the rat brain: forebrain cortex (FC), cerebellum (C) and hippocampus (H). The microscopic examinations showed alterations in hippocampal neurons.Our data shows that pre- and neonatal exposure of rats to Pb, leading to Pb-B below 10 μg/dL, can decrease the number of hippocampus neurons, occurring concomitantly with ultrastructural alterations in this region. We observed no morphological or molecular features of severe apoptosis or necrosis (no active Casp-3 and AIF translocation to nucleus) in young brains, despite the reduced levels of BDNF. The potential protective factor against apoptosis was probably the decreased Bax/Bcl-2 ratio, which requires further investigation. Our

  20. Learning, memory and synaptic plasticity in hippocampus in rats exposed to sevoflurane.

    Science.gov (United States)

    Xiao, Hongyan; Liu, Bing; Chen, Yali; Zhang, Jun

    2016-02-01

    Developmental exposure to volatile anesthetics has been associated with cognitive deficits at adulthood. Rodent studies have revealed impairments in performance in learning tasks involving the hippocampus. However, how the duration of anesthesia exposure impact on hippocampal synaptic plasticity, learning, and memory is as yet not fully elucidated. On postnatal day 7(P7), rat pups were divided into 3 groups: control group (n=30), 3% sevoflurane treatment for 1h (Sev 1h group, n=30) and 3% sevoflurane treatment for 6h (Sev 6h group, n=28). Following anesthesia, synaptic vesicle-associated proteins and dendrite spine density and synapse ultrastructure were measured using western blotting, Golgi staining, and transmission electron microscopy (TEM) on P21. In addition, the effects of sevoflurane treatment on long-term potentiation (LTP) and long-term depression (LTD), two molecular correlates of memory, were studied in CA1 subfields of the hippocampus, using electrophysiological recordings of field potentials in hippocampal slices on P35-42. Rats' neurocognitive performance was assessed at 2 months of age, using the Morris water maze and novel-object recognition tasks. Our results showed that neonatal exposure to 3% sevoflurane for 6h results in reduced spine density of apical dendrites along with elevated expression of synaptic vesicle-associated proteins (SNAP-25 and syntaxin), and synaptic ultrastructure damage in the hippocampus. The electrophysiological evidence indicated that hippocampal LTP, but not LTD, was inhibited and that learning and memory performance were impaired in two behavioral tasks in the Sev 6h group. In contrast, lesser structural and functional damage in the hippocampus was observed in the Sev 1h group. Our data showed that 6-h exposure of the developing brain to 3% sevoflurane could result in synaptic plasticity impairment in the hippocampus and spatial and nonspatial hippocampal-dependent learning and memory deficits. In contrast, shorter

  1. Parallel processing of information about location in the amygdala, entorhinal cortex and hippocampus.

    Science.gov (United States)

    Gaskin, Stephane; White, Norman M

    2013-11-01

    The conditioned cue preference paradigm was used to study how rats use extra-maze cues to discriminate between 2 adjacent arms on an 8-arm radial maze, a situation in which most of the same cues can be seen from both arms but only one arm contains food. Since the food-restricted rats eat while passively confined on the food-paired arm no responses are reinforced, so the discrimination is due to Pavlovian stimulus-reward (or outcome) learning. Consistent with other evidence that rats must move around in an environment to acquire a spatial map, we found that learning the adjacent arms CCP (ACCP) required a minimum amount of active exploration of the maze with no reinforcers present prior to passive pairing of the extra-maze cues with the food reinforcer, an instance of latent learning. Temporary inactivation of the hippocampus during the pre-exposure sessions had no effect on ACCP learning, confirming other evidence that the hippocampus is not involved in latent learning. A series of experiments indentified a circuit involving fimbria-fornix and dorsal entorhinal cortex as the neural basis of latent learning in this situation. In contrast, temporary inactivation of the entorhinal cortex or hippocampus during passive training or during testing blocked ACCP learning and expression, respectively, suggesting that these two structures co-operate in using spatial information to learn the location of food on the maze during passive pairing and to express this combined information during testing. In parallel with these processes we found that the amygdala processes information leading to an equal tendency to enter both adjacent arms (even though only one was paired with food) suggesting that the stimulus information available to this structure is not sufficiently precise to discriminate between the ambiguous cues visible from the adjacent arms. Expression of the ACCP in normal rats depends on hippocampus-based learning to avoid the unpaired arm which competes with the

  2. Studies of the macroscopic and microscopic morphology (hippocampus) of brain in Vencobb broiler

    Science.gov (United States)

    Gupta, Shailesh Kumar; Behera, Kumaresh; Pradhan, C. R.; Mandal, Arun Kumar; Sethy, Kamdev; Behera, Dayanidhi; Shinde, Kuladip Prakash

    2016-01-01

    Aim: The aim of this study was to study the anatomy of different parts of brain and histology of hippocampus of Vencobb broiler chicken. Materials and Methods: A 12 adult experimental birds were sacrificed by cervical dislocation. After separation of the brain, gross anatomy features were studied. Brain tissue was fixed in 10% buffered neutral formalin for 2-3 days, and then routine dehydration process in ascending grades of ethyl alcohol was done. After xylene cleaning, paraffin impregnation was prepared. Paraffin blocks were cut, and slides were stained by Harris hematoxylin and eosin. Photography was carried out both under lower (×10) and higher (×40) magnifications. Results: The brain structure (dorsal view) of Vencobb bird resembled the outline of a playing card symbol of a “spade.” The brain subdivisions are cerebrum, cerebellum, and medulla oblongata. Cerebrum was devoid of usual convolutions (elevations), gyri, depressions (grooves), and sulci. The cerebral hemispheres were tightly apposed along a median sulcus called interhemispheric fissure and cerebrum and cerebellum were separated by a small transverse fissure. The olfactory bulb was small structures, and the pineal body was clearly visible. The optic lobes were partially hidden under cerebral hemispheres, but laterally, it was large, prominent rounded or spherical bodies of the midbrain. The hippocampal area appeared as dorso-medial protrusion. Different types of neurons were distinguished in the hippocampus were pyramidal neurons, pyramidal-like neurons, and multipolar neurons, etc. There was rich vascularization in the form of blood capillaries throughout the hippocampus. Conclusion: Cerebrum was pear shaped and largest part of the brain. Cerebrum hemisphere was smooth devoid of convolutions, gyri, and depressions, but in the surface of cerebellum, there was the presence of a number of transverse depression (grooves) and sulci subdividing into many folds. Olfactory bulb was poorly developed

  3. Morphometric and functional alterations of amygdale and hippocampus in patients with depression: a MRI study

    International Nuclear Information System (INIS)

    Wang Dongqing; Li Yuefeng; Luo Yifeng

    2011-01-01

    Objective: To explore the morphometric and functional alterations of amygdale and hippocampus in patients with depression by anatomical and functional MRI, and try to reveal the pattern and pathogenesis of the changes in depression. Methods: Sixty patients (divided equally into mild, moderate and major groups according to patient's scores of HAMD) and 20 healthy control groups were scanned using T 1 WI and fMRI. The outlines of hippocampus and amygdale were drawn manually by observer and the volumes were calculated and normalized subsequently. Functional MRI was processed using SPM5 and individual activation map was got subsequently. Dunnett-t test and Pearson correlation analysis were separately used to analyze the morphometric and functional changes and the correlations between cerebral changes and clinical severity. Results: The hippocampal volumes of control groups were 2296±202 left for left side and 2283±199 for right side. The hippocampal volumes of depressive patients were smaller than those of control groups, especially for the major group (left 1978±176, Dunnett-t =-10.0, P 0.05, right 2210±191, Dunnett-t =-1.6, P>0.05). The amygdale's volumes of control groups was 1762±185, the right was 1749±182, while those in patient group reduced along with the patient's condition, i. e., the mild groups (left 1992±200, Dunnett-t =4.8, P<0.01, right 1989±191, Dunnett-t =5.0, P<0.001), the moderate groups (left 1889±192, Dunnett-t =2.8, P<0.05, right 1896±195, Dunnett-t =2.8, P<0.05), and the major groups (left 1539±178, Dunnett-t =-6.8, P<0.01, right 1543±180, Dunnett-t =-7.0, P< 0.01). For fMRI study, patient group demonstrated more activation of the amygdale and hippocampus under the stimulations of negative images than controls. Furthermore, the strengthens of activation decreased along with the patient's condition, i. e., the major ones showed the weakest activation among the patients, though it was higher than that of control group. In patient group

  4. Functional relationships between the hippocampus and dorsomedial striatum in learning a visual scene-based memory task in rats.

    Science.gov (United States)

    Delcasso, Sébastien; Huh, Namjung; Byeon, Jung Seop; Lee, Jihyun; Jung, Min Whan; Lee, Inah

    2014-11-19

    The hippocampus is important for contextual behavior, and the striatum plays key roles in decision making. When studying the functional relationships with the hippocampus, prior studies have focused mostly on the dorsolateral striatum (DLS), emphasizing the antagonistic relationships between the hippocampus and DLS in spatial versus response learning. By contrast, the functional relationships between the dorsomedial striatum (DMS) and hippocampus are relatively unknown. The current study reports that lesions to both the hippocampus and DMS profoundly impaired performance of rats in a visual scene-based memory task in which the animals were required to make a choice response by using visual scenes displayed in the background. Analysis of simultaneous recordings of local field potentials revealed that the gamma oscillatory power was higher in the DMS, but not in CA1, when the rat performed the task using familiar scenes than novel ones. In addition, the CA1-DMS networks increased coherence at γ, but not at θ, rhythm as the rat mastered the task. At the single-unit level, the neuronal populations in CA1 and DMS showed differential firing patterns when responses were made using familiar visual scenes than novel ones. Such learning-dependent firing patterns were observed earlier in the DMS than in CA1 before the rat made choice responses. The present findings suggest that both the hippocampus and DMS process memory representations for visual scenes in parallel with different time courses and that flexible choice action using background visual scenes requires coordinated operations of the hippocampus and DMS at γ frequencies. Copyright © 2014 the authors 0270-6474/14/3415534-14$15.00/0.

  5. Distinct roles of the hippocampus and perirhinal cortex in GABAA receptor blockade-induced enhancement of object recognition memory.

    Science.gov (United States)

    Kim, Jong Min; Kim, Dong Hyun; Lee, Younghwan; Park, Se Jin; Ryu, Jong Hoon

    2014-03-13

    It is well known that the hippocampus plays a role in spatial and contextual memory, and that spatial information is tightly regulated by the hippocampus. However, it is still highly controversial whether the hippocampus plays a role in object recognition memory. In a pilot study, the administration of bicuculline, a GABAA receptor antagonist, enhanced memory in the passive avoidance task, but not in the novel object recognition task. In the present study, we hypothesized that these different results are related to the characteristics of each task and the different roles of hippocampus and perirhinal cortex. A region-specific drug-treatment model was employed to clarify the role of the hippocampus and perirhinal cortex in object recognition memory. After a single habituation in the novel object recognition task, intra-perirhinal cortical injection of bicuculline increased and intra-hippocampal injection decreased the exploration time ratio to novel object. In addition, when animals were repeatedly habituated to the context, intra-perirhinal cortical administration of bicuculline still increased exploration time ratio to novel object, but the effect of intra-hippocampal administration disappeared. Concurrent increases of c-Fos expression and ERK phosphorylation were observed in the perirhinal cortex of the object with context-exposed group either after single or repeated habituation to the context, but no changes were noted in the hippocampus. Altogether, these results suggest that object recognition memory formation requires the perirhinal cortex but not the hippocampus, and that hippocampal activation interferes with object recognition memory by the information encoding of unfamiliar environment. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Glucose metabolic alterations in hippocampus of diabetes mellitus rats and the regulation of aerobic exercise.

    Science.gov (United States)

    Li, Jingjing; Liu, Beibei; Cai, Ming; Lin, Xiaojing; Lou, Shujie

    2017-11-04

    Diabetes could negatively affect the structures and functions of the brain, especially could cause the hippocampal dysfunction, however, the potential metabolic mechanism is unclear. The aim of this study was to investigate the changes of glucose metabolism in hippocampus of diabetes mellitus rats and the regulation of aerobic exercise, and to analyze the possible mechanisms. A rat model of type 2 diabetes mellitus was established by high-fat diet feeding in combination with STZ intraperitoneal injection, then 4 weeks of aerobic exercise was conducted. The glucose metabolites and key enzymes involved in glucose metabolism in hippocampus were respectively detected by GC/MS based metabolomics and western blot. Metabolomics results showed that compared with control rats, the level of citric acid was significantly decreased, while the levels of lactic acid, ribose 5-phosphate, xylulose 5-phosphate and glucitol were significantly increased in the diabetic rat. Compared with diabetic rats, the level of citric acid was significantly increased, while the lactic acid, ribose 5-phosphate and xylulose 5-phosphate were significantly decreased in the diabetic exercise rats. Western blot results showed that lower level of citrate synthase and oxoglutarate dehydrogenase, higher level of aldose reductase and glucose 6-phosphatedehydrogenase were found in the diabetic rats when compared to control rats. After 4 weeks of aerobic exercise, citrate synthase was upregulated and glucose 6-phosphatedehydrogenase was downregulated in the diabetic rats. These results suggest that diabetes could cause abnormal glucose metabolism, and aerobic exercise plays an important role in regulating diabetes-induced disorder of glucose metabolism in the hippocampus. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Quantified distribution of the noradrenaline innervation in the hippocampus of adult rat

    International Nuclear Information System (INIS)

    Oleskevich, S.; Descarries, L.; Lacaille, J.C.

    1989-01-01

    A recently developed radioautographic technique, based on the uptake labeling of monoamine terminals in vitro, was used to quantify the noradrenaline (NA) innervation in adult rat hippocampus. After incubation of brain slices with 1 microM 3H-NA, the NA varicosities were visualized as small aggregates of silver grains, in light microscope radioautographs prepared at 3 equidistant horizontal levels across the ventral 2/3 of the hippocampus. Using a computer-assisted image analyzer, counts were obtained from the subiculum (SUB), 3 sectors of Ammon's horn (CA1, CA3-a, CA3-b) and 3 sectors of the dentate gyrus (DG-medial blade, crest, and lateral blade), every lamina being sampled in each region. After a double correction for duration of radioautographic exposure and section thickness, and following measurement of varicosity diameter in electron microscope radioautographs, it was possible to express these results in number of terminals per volumetric unit of tissue. It was thus found that the overall density of hippocampal NA innervation averages 2.1 million varicosities/mm3 of tissue, a value almost twice as high as that in cerebral cortex. This innervation is 20% denser ventrally than dorsally and is heterogeneous both in terms of regional and laminar distribution. SUB and DG are more strongly innervated than Ammon's horn, wherein CA1 has the lowest overall density. In SUB and CA1, there is a clear predilection of NA varicosities for the stratum moleculare. In CA3, there is a narrow band of even stronger innervation in the stratum radiatum, near the apical border of the stratum pyramidale, contrasting with a 3 times lower density in this cell layer and the stratum oriens. In DG, the NA innervation is again the weakest in the cell body layer and exhibits an almost 3-fold greater density in the polymorph layer, the highest of all hippocampus

  8. Neuropathologic features in the hippocampus and cerebellum of three older men with fragile X syndrome

    Directory of Open Access Journals (Sweden)

    Greco Claudia M

    2011-02-01

    Full Text Available Abstract Background Fragile X syndrome (FXS is the most common inherited form of intellectual disability, and is the most common single-gene disorder known to be associated with autism. Despite recent advances in functional neuroimaging and our understanding of the molecular pathogenesis, only limited neuropathologic information on FXS is available. Methods Neuropathologic examinations were performed on post-mortem brain tissue from three older men (aged 57, 64 and 78 years who had received a clinical or genetic diagnosis of FXS. In each case, physical and cognitive features were typical of FXS, and one man was also diagnosed with autism. Guided by reports of clinical and neuroimaging abnormalities of the limbic system and cerebellum of individuals with FXS, the current analysis focused on neuropathologic features present in the hippocampus and the cerebellar vermis. Results Histologic and immunologic staining revealed abnormalities in both the hippocampus and cerebellar vermis. Focal thickening of hippocampal CA1 and irregularities in the appearance of the dentate gyrus were identified. All lobules of the cerebellar vermis and the lateral cortex of the posterior lobe of the cerebellum had decreased numbers of Purkinje cells, which were occasionally misplaced, and often lacked proper orientation. There were mild, albeit excessive, undulations of the internal granular cell layer, with patchy foliar white matter axonal and astrocytic abnormalities. Quantitative analysis documented panfoliar atrophy of both the anterior and posterior lobes of the vermis, with preferential atrophy of the posterior lobule (VI to VII compared with age-matched normal controls. Conclusions Significant morphologic changes in the hippocampus and cerebellum in three adult men with FXS were identified. This pattern of pathologic features supports the idea that primary defects in neuronal migration, neurogenesis and aging may underlie the neuropathology reported in FXS.

  9. Preferential loss of dorsal-hippocampus synapses underlies memory impairments provoked by short, multimodal stress.

    Science.gov (United States)

    Maras, P M; Molet, J; Chen, Y; Rice, C; Ji, S G; Solodkin, A; Baram, T Z

    2014-07-01

    The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress.

  10. Learning not to respond: Role of the hippocampus in withholding responses during omission training.

    Science.gov (United States)

    White, Norman M; Naeem, Maliha

    2017-02-01

    Autoshaping is a Pavlovian learning paradigm in which rats experience pairings of a CS and a US independently of their behavior. When the CS is a lever inserted into the test cage and the US is food delivered to an adjacent magazine, many rats acquire a lever-pressing response called 'sign-tracking' even though that response has no effect on the occurrence of either the CS or the US. Since these lever presses are always followed by the US, it has been suggested that sign-tracking could be due to unintended reinforcement of the response. To eliminate the possibility of such instrumental learning the omission schedule, in which a response to the CS cancels the US, was introduced. Previous research has shown that training rats on autoshaping and switching them to an omission schedule generally reduces but does not eliminate sign-tracking, suggesting that it may be due to both Pavlovian and instrumental learning. In the present study naive rats trained on an omission schedule sign-tracked less than a control group exposed to random, unpaired CS and US presentations, suggesting that they learned to withhold the lever press response because of the negative contingency between that response and the US. In a second experiment rats with dorsal hippocampus lesions sign-tracked more than sham-lesioned rats on omission schedules, suggesting that this case of learning not to respond is hippocampus-based. This conclusion is consistent with many previous findings on the inability of hippocampal rats to withhold or suppress responding, and with studies suggesting that one form of extinction of learned responses in normal rats is due to competition from hippocampus-based learning not to respond. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Genetic variation of the RASGRF1 regulatory region affects human hippocampus-dependent memory

    Directory of Open Access Journals (Sweden)

    Adriana eBarman

    2014-04-01

    Full Text Available The guanine nucleotide exchange factor RASGRF1 is an important regulator of intracellular signaling and neural plasticity in the brain. RASGRF1-deficient mice exhibit a complex phenotype with learning deficits and ocular abnormalities. Also in humans, a genome-wide association study has identified the single nucleotide polymorphism (SNP rs8027411 in the putative transcription regulatory region of RASGRF1 as a risk variant of myopia. Here we aimed to assess whether, in line with the RASGRF1 knockout mouse phenotype, rs8027411 might also be associated with human memory function. We performed computer-based neuropsychological learning experiments in two independent cohorts of young, healthy participants. Tests included the Verbal Learning and Memory Test (VLMT and the logical memory section of the Wechsler Memory Scale (WMS. Two sub-cohorts additionally participated in functional magnetic resonance imaging (fMRI studies of hippocampus function. 119 participants performed a novelty encoding task that had previously been shown to engage the hippocampus, and 63 subjects participated in a reward-related memory encoding study. RASGRF1 rs8027411 genotype was indeed associated with memory performance in an allele dosage-dependent manner, with carriers of the T allele (i.e. the myopia risk allele showing better memory performance in the early encoding phase of the VLMT and in the recall phase of the WMS logical memory section. In fMRI, T allele carriers exhibited increased hippocampal activation during presentation of novel images and during encoding of pictures associated with monetary reward. Taken together, our results provide evidence for a role of the RASGRF1 gene locus in hippocampus-dependent memory and, along with the previous association with myopia, point towards pleitropic effects of RASGRF1 genetic variations on complex neural function in humans.

  12. Inorganic Arsenic Induces NRF2-Regulated Antioxidant Defenses in Both Cerebral Cortex and Hippocampus in Vivo.

    Science.gov (United States)

    Zhang, Yang; Duan, Xiaoxu; Li, Jinlong; Zhao, Shuo; Li, Wei; Zhao, Lu; Li, Wei; Nie, Huifang; Sun, Guifang; Li, Bing

    2016-08-01

    Inorganic arsenic is reported to induce the reactive oxygen species-mediated oxidative stress, which is supposed to be one of the main mechanisms of arsenic-related neurological diseases. Nuclear factor erythroid 2-related factor 2 (NRF2), a master regulator of antioxidant defense systems, up-regulates the expression of target genes to fight against oxidative damages caused by harmful substances, including metals. In the present study, mice were used as a model to investigate the oxidative stress levels and the expressions of NRF2-regulated antioxidant substances in both cerebral cortex and hippocampus with 5, 10 and 20 mg/kg NaAsO2 exposure intra-gastrically. Our results showed that acute NaAsO2 treatment resulted in decreased total anti-oxidative capacity (T-AOC) and increased maleic dialdehyde production in the nervous system. We also detected rapidly elevation of NRF2 protein levels by enhancement of Nrf2 transcription, especially at 20 mg/kg NaAsO2 exposure group. In the meantime, mRNA and protein levels of Nrf2 encoding antioxidant enzymes heme oxygenase-1 (HO-1), NAD(P)H: quinine oxidoreductase 1 (NQO1) and glutathione S-transferase (GST) were consistently elevated time- and dose-dependently both in the cerebral cortex and hippocampus. Taken together, the presence study demonstrated the activation of NRF2 pathway, an early antioxidant defensive response, in both cerebral cortex and hippocampus upon inorganic arsenic (iAs) exposure in vivo. A better knowledge on the roles of NRF2 pathway in maintaining cellular redox homeostasis would be helpful for the strategies on improvement of neurotoxicity related to this metalloid.

  13. Distribution Pattern of Seahorse species (Genus: Hippocampus in Tamilnadu and Kerala Coasts of India

    Directory of Open Access Journals (Sweden)

    Aaron Premnath LIPTON

    2013-02-01

    Full Text Available The survey along the Tamilnadu and Kerala coats of India reveled that six species of seahors (Hippocampus fuscus, H. kelloggi, H. kuda, H. histrix H. mohnikei and H. trimaculatus were distributed with different density. Out of the six species, H. fuscus, H. kuda and H. trimaculatus, were the commonly available species in all the observed areas. In Palk Bay, H. kuda was the dominant species constituting 49.10% of the total seahorses encountered. Hippocampus trimaculatus was the second dominant species which accounting 39.28%. The Gulf of Mannar region also most abounded with H. kuda (68.98% followed by H. trimaculatus (20.80%, H. fuscus (9.80%, H. kelloggi (2.23% and H. histrix (0.37%. In Kerala coast, H. trimaculatus was the dominant species (79.68% followed by H. kuda (9.89%, H. kelloggi (8.33% and H. fuscus (2.08%. To infer the variation of six seahorse species the morphometric and meristic characters were analysed. The important morphometric and meristic characters are trunk rings, tail rings, pectoral and dorsal fin rays, trunk length, tail length, coronet height, head length, snout length, snout depth and head depth. Variation in overall body shape, relative snout length, coronet height, number of tail ring was sufficient to separate the specimens to Hippocampus fuscus, H. kelloggi, H. kuda, H. histrix H. mohnikei and H.trimaculatus. The species density and diversity depends on the habitat and biogeography of those areas. Majority of seahorse fishing in Tamilnadu was by shrimp trawl, by-catch and very few target catch by divers also seen in some villages of Palk Bay and Gulf of Mannar region. The shrimp trawl by-catch only bringing more H. trimaculatus than the other species in Kerala coasts.

  14. Neuropathologic features of the hippocampus and amygdala in cats with familial spontaneous epilepsy.

    Science.gov (United States)

    Yu, Yoshihiko; Hasegawa, Daisuke; Hamamoto, Yuji; Mizoguchi, Shunta; Kuwabara, Takayuki; Fujiwara-Igarashi, Aki; Tsuboi, Masaya; Chambers, James Ken; Fujita, Michio; Uchida, Kazuyuki

    2018-03-01

    OBJECTIVE To investigate epilepsy-related neuropathologic changes in cats of a familial spontaneous epileptic strain (ie, familial spontaneous epileptic cats [FSECs]). ANIMALS 6 FSECs, 9 age-matched unrelated healthy control cats, and 2 nonaffected (without clinical seizures)dams and 1 nonaffected sire of FSECs. PROCEDURES Immunohistochemical analyses were used to evaluate hippocampal sclerosis, amygdaloid sclerosis, mossy fiber sprouting, and granule cell pathological changes. Values were compared between FSECs and control cats. RESULTS Significantly fewer neurons without gliosis were detected in the third subregion of the cornu ammonis (CA) of the dorsal and ventral aspects of the hippocampus as well as the central nucleus of the amygdala in FSECs versus control cats. Gliosis without neuronal loss was also observed in the CA4 subregion of the ventral aspect of the hippocampus. No changes in mossy fiber sprouting and granule cell pathological changes were detected. Moreover, similar changes were observed in the dams and sire without clinical seizures, although to a lesser extent. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that the lower numbers of neurons in the CA3 subregion of the hippocampus and the central nucleus of the amygdala were endophenotypes of familial spontaneous epilepsy in cats. In contrast to results of other veterinary medicine reports, severe epilepsy-related neuropathologic changes (eg, hippocampal sclerosis, amygdaloid sclerosis, mossy fiber sprouting, and granule cell pathological changes) were not detected in FSECs. Despite the use of a small number of cats with infrequent seizures, these findings contributed new insights on the pathophysiologic mechanisms of genetic-related epilepsy in cats.

  15. Estradiol enhances retention but not organization of hippocampus-dependent memory in intact male mice.

    Science.gov (United States)

    Al Abed, Alice Shaam; Sellami, Azza; Brayda-Bruno, Laurent; Lamothe, Valérie; Noguès, Xavier; Potier, Mylène; Bennetau-Pelissero, Catherine; Marighetto, Aline

    2016-07-01

    Because estrogens have mostly been studied in gonadectomized females, effects of chronic exposure to environmental estrogens in the general population are underestimated. Estrogens can enhance hippocampus-dependent memory through the modulation of information storage. However, declarative memory, the hippocampus-dependent memory of facts and events, demands more than abilities to retain information. Specifically, memory of repetitive events of everyday life such as "where I parked" requires abilities to organize/update memories to prevent proactive interference from similar memories of previous "parking events". Whether such organizational processes are estrogen-sensitive is unknown. We here studied, in intact young and aged adult mice, drinking-water (1μM) estradiol effects on both retention and organizational components of hippocampus-dependent memory, using a radial-maze task of everyday-like memory. Demand on retention vs organization was manipulated by varying the time-interval separating repetitions of similar events. Estradiol increased performance in young and aged mice under minimized organizational demand, but failed to improve the age-associated memory impairment and diminished performance in young mice under high organizational demand. In fact, estradiol prolonged mnemonic retention of successive events without improving organization abilities, hence resulted in more proactive interference from irrelevant memories. c-Fos imaging of testing-induced brain activations showed that the deterioration of young memory was associated with dentate gyrus dysconnectivity, reminiscent of that seen in aged mice. Our findings support the view that estradiol is promnesic but also reveal that such property can paradoxically impair memory. These findings have important outcomes regarding health issues relative to the impact of environmental estrogens in the general population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Decoding Illusory Self-location from Activity in the Human Hippocampus

    Directory of Open Access Journals (Sweden)

    Arvid eGuterstam

    2015-07-01

    Full Text Available Decades of research have demonstrated a role for the hippocampus in spatial navigation and episodic and spatial memory. However, empirical evidence linking hippocampal activity to the perceptual experience of being physically located at a particular place in the environment is lacking. In this study, we used a multisensory out-of-body illusion to perceptually ‘teleport’ six healthy participants between two different locations in the scanner room during high-resolution functional magnetic resonance imaging (fMRI. The participants were fitted with MRI-compatible head-mounted displays that changed their first-person visual perspective to that of a pair of cameras placed in one of two corners of the scanner room. To elicit the illusion of being physically located in this position, we delivered synchronous visuo-tactile stimulation in the form of an object moving towards the cameras coupled with touches applied to the participant’s chest. Asynchronous visuo-tactile stimulation did not induce the illusion and served as a control condition. We found that illusory self-location could be successfully decoded from patterns of activity in the hippocampus in all of the participants in the synchronous (P0.05. At the group-level, the decoding accuracy was significantly higher in the synchronous than in the asynchronous condition (P=0.012. These findings associate hippocampal activity with the perceived location of the bodily self in space, which suggests that the human hippocampus is involved not only in spatial navigation and memory but also in the construction of our sense of bodily self-location.

  17. Preferential loss of dorsal-hippocampus synapses underlies memory impairments provoked by short, multimodal stress

    Science.gov (United States)

    Maras, P M; Molet, J; Chen, Y; Rice, C; Ji, S G; Solodkin, A; Baram, T Z

    2014-01-01

    The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress. PMID:24589888

  18. Neuropathologic features in the hippocampus and cerebellum of three older men with fragile X syndrome

    Science.gov (United States)

    2011-01-01

    Background Fragile X syndrome (FXS) is the most common inherited form of intellectual disability, and is the most common single-gene disorder known to be associated with autism. Despite recent advances in functional neuroimaging and our understanding of the molecular pathogenesis, only limited neuropathologic information on FXS is available. Methods Neuropathologic examinations were performed on post-mortem brain tissue from three older men (aged 57, 64 and 78 years) who had received a clinical or genetic diagnosis of FXS. In each case, physical and cognitive features were typical of FXS, and one man was also diagnosed with autism. Guided by reports of clinical and neuroimaging abnormalities of the limbic system and cerebellum of individuals with FXS, the current analysis focused on neuropathologic features present in the hippocampus and the cerebellar vermis. Results Histologic and immunologic staining revealed abnormalities in both the hippocampus and cerebellar vermis. Focal thickening of hippocampal CA1 and irregularities in the appearance of the dentate gyrus were identified. All lobules of the cerebellar vermis and the lateral cortex of the posterior lobe of the cerebellum had decreased numbers of Purkinje cells, which were occasionally misplaced, and often lacked proper orientation. There were mild, albeit excessive, undulations of the internal granular cell layer, with patchy foliar white matter axonal and astrocytic abnormalities. Quantitative analysis documented panfoliar atrophy of both the anterior and posterior lobes of the vermis, with preferential atrophy of the posterior lobule (VI to VII) compared with age-matched normal controls. Conclusions Significant morphologic changes in the hippocampus and cerebellum in three adult men with FXS were identified. This pattern of pathologic features supports the idea that primary defects in neuronal migration, neurogenesis and aging may underlie the neuropathology reported in FXS. PMID:21303513

  19. A Review of Adversity, The Amygdala and the Hippocampus: A Consideration of Developmental Timing

    Science.gov (United States)

    Tottenham, Nim; Sheridan, Margaret A.

    2009-01-01

    A review of the human developmental neuroimaging literature that investigates outcomes following exposure to psychosocial adversity is presented with a focus on two subcortical structures – the hippocampus and the amygdala. Throughout this review, we discuss how a consideration of developmental timing of adverse experiences and age at measurement might provide insight into the seemingly discrepant findings across studies. We use findings from animal studies to suggest some mechanisms through which timing of experiences may result in differences across time and studies. The literature suggests that early life may be a time of heightened susceptibility to environmental stressors, but that expression of these effects will vary by age at measurement. PMID:20161700

  20. Primary Blast-Induced Changes in Akt and GSK3β Phosphorylation in Rat Hippocampus

    Directory of Open Access Journals (Sweden)

    Yushan Wang

    2017-08-01

    Full Text Available Traumatic brain injury (TBI due to blast from improvised explosive devices has been a leading cause of morbidity and mortality in recent conflicts in Iraq and Afghanistan. However, the mechanisms of primary blast-induced TBI are not well understood. The Akt signal transduction pathway has been implicated in various brain pathologies including TBI. In the present study, the effects of simulated primary blast waves on the phosphorylation status of Akt and its downstream effector kinase, glycogen synthase kinase 3β (GSK3β, in rat hippocampus, were investigated. Male Sprague-Dawley (SD rats (350–400 g were exposed to a single pulse shock wave (25 psi; ~7 ms duration and sacrificed 1 day, 1 week, or 6 weeks after exposure. Total and phosphorylated Akt, as well as phosphorylation of its downstream effector kinase GSK3β (at serine 9, were detected with western blot analysis and immunohistochemistry. Results showed that Akt phosphorylation at both serine 473 and threonine 308 was increased 1 day after blast on the ipsilateral side of the hippocampus, and this elevation persisted until at least 6 weeks postexposure. Similarly, phosphorylation of GSK3β at serine 9, which inhibits GSK3β activity, was also increased starting at 1 day and persisted until at least 6 weeks after primary blast on the ipsilateral side. In contrast, p-Akt was increased at 1 and 6 weeks on the contralateral side, while p-GSK3β was increased 1 day and 1 week after primary blast exposure. No significant changes in total protein levels of Akt and GSK were observed on either side of the hippocampus at any time points. Immunohistochemical results showed that increased p-Akt was mainly of neuronal origin in the CA1 region of the hippocampus and once phosphorylated, the majority was translocated to the dendritic and plasma membranes. Finally, electrophysiological data showed that evoked synaptic N-methyl-d-aspartate (NMDA receptor activity was

  1. Quantitative analysis of neuronal mosaic formation in the mouse neocortex and hippocampus

    International Nuclear Information System (INIS)

    Reznikov, K.Yu.; Nazarevskaya, G.D.; Deryabin, V.E.

    1987-01-01

    The authors obtain mathematical confirmation of the nonrandomness of mosaic formation of neuronal groups in the cerebral cortex, characterize this process quantitatively, and compare its scale with the formation of the modular organization of the cortex. Mice were used in the experiments and were injected with 3 H-thymidine while pregnant. Mapping in the neocortex was carried out on frontal semithin brain sections from mice receiving 3 H-thymidine from E15 through E17, whereas mapping in the hippocampus was carried out on paraffin and semithin frontal brain sections from animals receiving the isotope from E13 through E17

  2. Activity-regulated RNA editing in select neuronal subfields in hippocampus

    Czech Academy of Sciences Publication Activity Database

    Balík, Aleš; Penn, A.C.; Nemoda, Z.; Greger, I. H.

    2013-01-01

    Roč. 41, č. 2 (2013), s. 1124-1134 ISSN 0305-1048 R&D Projects: GA ČR(CZ) GBP304/12/G069 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M200110971; Medical Research Council(GB) U105174197 Institutional support: RVO:67985823 Keywords : hippocampus * RNA * adenosine Subject RIV: ED - Physiology Impact factor: 8.808, year: 2013

  3. Cathepsin B inhibitory activities of three new phthalate derivatives isolated from seahorse, Hippocampus Kuda Bleeler.

    Science.gov (United States)

    Li, Yong; Qian, Zhong-Ji; Kim, Se-Kwon

    2008-12-01

    Three new phthalate acid derivatives, 2,12-diethyl-11-methylhexadecyl 2-ethyl-11-methylhexadecyl phthalate (1), 2-ethyldecyl 2-ethylundecyl phthalate (2), and bis(2-ethyldodecyl) phthalate (3), were isolated from seahorse, Hippocampus Kuda Bleeler, together with a known natural analog bis(2-ethylheptyl) phthalate (4). The structures of these compounds were elucidated mainly by means of the comprehensive analysis of their NMR spectroscopic data. The four phthalate derivatives showed dose-dependent cathepsin B inhibitions activities with IC(50) values of 0.13 mM (1), 0.21 mM (2), 0.18 mM (3), and 0.29 mM (4), respectively.

  4. Pair replacement on the spawning success of broodstock Seahorse (Hippocampus barbouri

    Directory of Open Access Journals (Sweden)

    . Syafiuddin

    2011-01-01

    Full Text Available Seahorse, (Hippocampus barbouri is one of marine living resources having high commercial values and has commonly been traded especially as live ornamental aquarium fish, raw material of traditional medicine and as souvenirs. This expriment was conducted to determine the succces of spawning rate by replacing the broodstock pair of seahorse. This study was done experimentally with treatment of replacement of broodstock pair after spawning under control condition. The experiment was designed to apply completely randomize design by using the following treatments: Treatment A, without replacement neither male nor female. Treatment B, spawned female broodstock  was being mated with her unpaired male broodstock.  Treatment C, a male broodstock that still brood was being mated with his unpaired female broodstock.  Treatment D, a spawned male broodstock that has released larva was being mated with his unpaired female broodstock.  Results showed that under control condition the replacement of broodstock pairs of seahorse had significantly influenced the spawning interval, number of eggs released and number of juveniles produced (P0,05.  It can be concluded that seahorse is not monogamous, either male or female after being spawned may accept other pair for the next spawning. Key words: pair replacement, broodstock, success spawning, Hippocampus barbouri   ABSTRAK Kuda laut, (Hippocampus barbouri merupakan salah satu sumberdaya hayati laut yang memiliki nilai komersial dan telah banyak diperdagangkan terutama sebagai ikan hias, bahan baku obat tradisional dan juga sebagai suvenir. Penelitian ini dilakukan dengan tujuan untuk mengkaji tingkat keberhasilan pemijahan dengan penggantian pasangan induk kuda laut pada wadah budidaya. Percobaan ini dilakukan secara ekperimental dengan perlakuan penggantian pasangan induk setelah pemijahan dalam wadah budidaya. Percobaan dirancang dengan menggunakan rancangan acak lengkap (RAL dengan perlakuan sebagai berikut

  5. Complete mitochondrial genome sequence of the Barbour's seahorse Hippocampus barbouri Jordan & Richardson, 1908 (Gasterosteiformes: Syngnathidae).

    Science.gov (United States)

    Wang, Bo; Zhang, Yanhong; Zhang, Huixian; Lin, Qiang

    2015-01-01

    The complete mitochondrial genome sequence of the Barbour's seahorse Hippocampus barbouri was first determined in this paper. The total length of H. barbouri mitogenome is 16,526 bp, which consists of 13 protein-coding genes, 22 tRNA and 2 rRNA genes and 1 control region. The features of the H. barbouri mitochondrial genome were similar to the typical vertebrates. The overall base composition of H. barbouri is 32.68% A, 29.75% T, 22.91% C and 14.66% G, with an AT content of 62.43%.

  6. Complete mitochondrial genome sequence of the lined seahorse Hippocampus erectus Perry, 1810 (Gasterosteiformes: Syngnathidae).

    Science.gov (United States)

    Zhang, Yanhong; Zhang, Huixian; Lin, Qiang; Huang, Liangmin

    2015-01-01

    The complete mitochondrial genome sequence of the lined seahorse Hippocampus erectus was first determined in this article. The total length of H. erectus mitogenome is 16,529 bp, which consists of 13 protein-coding genes, 22 tRNA and 2 rRNA genes and 1 control region. The features of the H. erectus mitochondrial genome were similar to the typical vertebrates. The overall base composition of H. erectus is 31.8% A, 28.6% T, 24.3% C and 15.3% G, with a slight A + T rich feature (60.4%).

  7. Complete mitochondrial genome of the pacific seahorse Hippocampus ingens Girard, 1858 (Gasterosteiformes: Syngnathidae).

    Science.gov (United States)

    Zhang, Huixian; Zhang, Yanhong; Lin, Qiang

    2015-01-01

    The complete mitochondrial genome sequence of the pacific seahorse Hippocampus ingens was determined using long polymerase chain reactions. The total length of H. ingens mitogenome is 16,526 bp and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition of H. ingens were similar to those of most other vertebrates. The overall base composition of H. ingens is 32.6% A, 29.3% T, 23.5% G and 14.6% C, with a slight A+T rich feature (61.9%).

  8. Novel sex-related characteristics of the longsnout seahorse Hippocampus reidi Ginsburg, 1933

    Directory of Open Access Journals (Sweden)

    Tacyana P. R Oliveira

    Full Text Available This paper presents novel sex-related characteristics in Hippocampus reidi, expressed as a prominent and pigmented keel (males only, and by a row of dorsolateral spots mostly (97.4% found in males. While the keel was found even in the smallest males sampled, the dorsolateral spots appear to be associated with body size. Ex situ observations revealed that during courtship males highlighted both characters by turning pale their background body colour. Understanding such colour and behavioural patterns is relevant to increase our knowledge about sexual selection in a morphologically and biologically unique group of fishes.

  9. Complete mitochondrial genome sequence of the longsnout seahorse Hippocampus reidi (Ginsburg, 1933; Gasterosteiformes: Syngnathidae).

    Science.gov (United States)

    Wang, Xin; Zhang, Yanhong; Zhang, Huixian; Meng, Tan; Lin, Qiang

    2016-01-01

    The complete mitochondrial genome sequence of the longsnout seahorse Hippocampus reidi was fisrt determined in this article. The total length of H. reidi mitogenome is 16,529 bp and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 control region. The gene order and composition of H. reidi were similar to those of most other vertebrates. The overall base composition of H. reidi is 32.47% A, 29.41% T, 14.75% G and 23.37% C, with a slight A + T rich feature (61.88%).

  10. Imaging the dorsal hippocampus: light reflectance relationships to electroencephalographic patterns during sleep

    DEFF Research Database (Denmark)

    Rector, D M; Poe, G R; Kristensen, Morten Pilgaard

    1995-01-01

    We assessed the correspondence of 660 nm light reflectance changes from the dorsal hippocampus with slow wave electroencephalographic (EEG) activity during quiet sleep (QS) and rapid eye movement (REM) sleep in four cats. An optic probe, attached to a charge-coupled-device (CCD) video camera...... as EEG changes. Dividing the image into 10 subregions revealed that reflectance changes at the rhythmical slow wave activity band (RSA, 4-6 Hz) persisted in localized regions during QS and REM sleep, but regional changes showed considerable wave-by-wave independence between areas and from slow wave...

  11. Rats use hippocampus to recognize positions of objects located in an inaccessible space

    Czech Academy of Sciences Publication Activity Database

    Levčík, David; Nekovářová, Tereza; Stuchlík, Aleš; Klement, Daniel

    2013-01-01

    Roč. 23, č. 2 (2013), s. 153-161 ISSN 1050-9631 R&D Projects: GA MZd(CZ) NT13386; GA ČR(CZ) GBP304/12/G069 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M200111204 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : hippocampus * object-position recognition * operant conditioning * muscimol * spatial cognition Subject RIV: FH - Neurology Impact factor: 4.302, year: 2013

  12. Prefrontal cortex and hippocampus in behavioural flexibility and posttraumatic functional recovery

    DEFF Research Database (Denmark)

    Rytter, Hana Malá; Andersen, Lykke Grønbech; Christensen, Rie Friis

    2015-01-01

    -shifting. Postoperatively, the animals were trained to perform a spatial discrimination go-right task. This was followed by (1) a spatial reversal go-left task (reversal learning), or (2) a visual pattern discrimination task (set-shift). Neither single (PFC or FF) lesion nor combined (COMB) lesions affected the animals....... We conclude that both the PFC and the hippocampus contributed to the mediation of the reversal learning and set-shifting. During functional recovery of reversal learning, these two structures exhibited a mutual dependency, whilst the functional recovery of set-shifting was mediated by a substrate...

  13. Sox1 marks an activated neural stem/progenitor cell in the hippocampus

    OpenAIRE

    Venere, Monica; Han, Young-Goo; Bell, Robert; Song, Jun S.; Alvarez-Buylla, Arturo; Blelloch, Robert

    2012-01-01

    The dentate gyrus of the hippocampus continues generating new neurons throughout life. These neurons originate from radial astrocytes within the subgranular zone (SGZ). Here, we find that Sox1, a member of the SoxB1 family of transcription factors, is expressed in a subset of radial astrocytes. Lineage tracing using Sox1-tTA;tetO-Cre;Rosa26 reporter mice shows that the Sox1-expressing cells represent an activated neural stem/progenitor population that gives rise to most if not all newly born ...

  14. Pattern separation: a common function for new neurons in hippocampus and olfactory bulb.

    Science.gov (United States)

    Sahay, Amar; Wilson, Donald A; Hen, René

    2011-05-26

    While adult-born neurons in the olfactory bulb (OB) and the dentate gyrus (DG) subregion of the hippocampus have fundamentally different properties, they may have more in common than meets the eye. Here, we propose that new granule cells in the OB and DG may function as modulators of principal neurons to influence pattern separation and that adult neurogenesis constitutes an adaptive mechanism to optimally encode contextual or olfactory information. See the related Perspective from Aimone, Deng, and Gage, "Resolving New Memories: A Critical Look at the Dentate Gyrus, Adult Neurogenesis, and Pattern Separation," in this issue of Neuron. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Gamma Radiation (5-10 Gy) Impairs Neuronal Function in the Guinea Pig Hippocampus

    Science.gov (United States)

    1993-01-01

    Radiation (5-10 Gy) Impairs Neuronal Function in the Guinea Pig Hippocampus TERRY C. PELLMAR AND DENNIS L. LEPINSKI Ph.vsiology Department..Irmned Forces...L. Gamma Radiation ioral effects. Within hours of irradiation with 10 Gy and (5- 10 Gy) Impairs Neuronal Function in the Guinea Pig Hippo- less...acti v- Guinea pigs were exposed to 5 and 10 Gy ’y radiation. Hippo- ity (9) are evident. campal brain slices were isolated 30 min, I day, 3 days and 5

  16. Selective localization of different types of opiate receptors in hippocampus as revealed by in vitro autoradiography

    International Nuclear Information System (INIS)

    Duka, T.; Wuester, M.; Schubert, P.; Stoiber, R.; Herz, A.

    1981-01-01

    The visualization of opiate binding sites within the hippocampus of the rat has been achieved by means of an in vitro autoradiography. In line with the concept of multiple opiate receptors, different opioid agonists revealed a particular distribution pattern. Whereas the selective delta-receptor agonist [ 3 H]D-Ala 2 , D-Leu 5 -enkephalin specifically labelled binding sites in the CA 2 area, [ 3 H]etorphine grains displayed a uniform dense distribution throughout the pyramidal cell layers from CA 1 to CA 4 . (Auth.)

  17. Effect of thyroxine on munc-18 and syntaxin-1 expression in dorsal hippocampus of adult-onset hypothyroid rats

    Directory of Open Access Journals (Sweden)

    Y. Zhu

    2012-05-01

    Full Text Available Adult-onset hypothyroidism induces a variety of impairments on hippocampus- dependent neurocognitive functioningin which many synaptic proteins in hippocampus neurons are involved. Here, we observed the effect of adult-onset hypothyroidism on the expression of syntaxin-1 and munc-18 in the dorsal hippocampus and whether the altered proteins could be restored by levothyroxine (T4 treatment. All rats were separated into 4 groups randomly: hypothyroid group, 5μg T4/100 g body weight (BW treated group, 20 μg T4/100g BW treated group and control group. The radioimmunoassay kits were applied to assay the levels of serum T3 and T4, and the levels of syntaxin-1 and munc-18 in hippocampus were assessed by immunohistochemistry and Western blot. Both analysis corroborated that syntaxin-1 in the hypothyroid group was significantly higher. Munc-18 was lower in four layers of CA3 and dentate gyrus by immunohistochemistry. After two weeks of treatment with 5 μg T4/100g BW for hypothyroidism, syntaxin-1 levels were completely restored, whereas the recovery of munc-18 only located in two of the four impaired layers. Twenty μg T4/100g BW treatment normalized munc-18 levels. These data suggested that adult-onset hypothyroidism induced increment of syntaxin-1 and decrement of munc-18 in the dorsal hippocampus, which could be restored by T4 treatment. Larger dosage of T4 caused more effective restorations.

  18. Combined lesions of hippocampus and subiculum Do not produce deficits in a nonspatial social olfactory memory task.

    Science.gov (United States)

    Burton, S; Murphy, D; Qureshi, U; Sutton, P; O'Keefe, J

    2000-07-15

    Rats transmit information to each other about which foods are safe to eat. If a rat smells a food odor on the breath of another rat, it is subsequently more likely to eat that food than an alternative. Work by Galef et al. (1988) has shown that the observer rat forms an association between two olfactory stimuli on the breath of the demonstrator rat that has eaten the food, the food odor and carbon disulphide, which is normally present in the rat breath. Bunsey and Eichenbaum (1995) claimed that the hippocampus/subicular region is required for the long-term retention of this nonspatial form of associative memory on the basis that combined lesions of the hippocampus and subiculum produced a deficit, but lesions of either structure alone did not. We report here a failure to repeat this finding. Rats with either combined lesions of the hippocampus and subiculum or with amygdala lesions were tested on their ability to remember this association either immediately (testing short-term memory) or after a 24 hr delay (testing long-term memory). Neither lesion group exhibited significant memory deficits on this nonspatial associative task at either test interval. In contrast, a deficit was observed on a spatial memory task (forced-choice alternation t-maze) for animals with combined lesions of the hippocampus and subiculum. These results contradict the findings of Bunsey and Eichenbaum (1995) and support the idea that the hippocampus/subicular region is not required for this nonspatial associative memory.

  19. ONE PROBABLE MECHANISM OF THE LEARNING-MEMORY DAMAGE BY LEAD: THE CHANGES OF NOS IN HIPPOCAMPUS

    Institute of Scientific and Technical Information of China (English)

    王静; 赵义; 杨章民; 张进; 李积胜; 司履生; 王一理

    2003-01-01

    Objective To study the effects of lead on the activity and expression of nitric oxide synthase (NOS) and relationship between the effects of lead on learning-memory and changes of NOS in subfields of hippocampus. Methods Y-maze test was used to study the effects of lead on ability of learning-memory; NADPH-d histochemistry and immunohistochemistry methods were used to investigate the changes of NOS in subfields of hippocampus. Results Compared with the control group, the ability of learning- memory in lead-exposed rats was significantly decreased (P<0.05); the number of NOS positive neurons in CA1 region and dentate gyrus of lead-exposed rats was significantly decreased(P<0.05), but no marked changes in CA3 region; the number of nNOS positive neurons in CA1 of lead-exposed rats was also significantly decreased(P<0.05), but no obvious changes in CA3. Conclusion Lead could damage the ability of learning-memory in rats. Lead could decrease the activity and expression of NOS in hippocampus and had different effects on NOS in different subfields of hippocampus. The changes of NOS in hippocampus induced by lead may be the mechanism of the learning-memory damage by lead.

  20. 1H-MR spectroscopy of the rat hippocampus after whole brain irradiation: an in vivo study

    International Nuclear Information System (INIS)

    Ding Weijun; Yang Haihua; Wang Xufeng; Hu Wei; Lei Hao; Li Chunxia; Fang Fang; Fang Zhouxi

    2008-01-01

    Objective: To study the relationships between dynamic changes of the hippocampus metabolites, cognitive impairment and ultrastructural changes of hippocampus in rats during the initial 4 weeks after 6 MV X-ray whole-brain irradiation. Methods: 65 rats were randomly divided into foul groups as sham control (n=5), 10 Gy, 20 Gy and 30 Gy groups (n=20). The learning and memory ability was measured with the Y maze test 4, 8 weeks, 2, 6 months after irradiation. 1 H-MRS was performed after 2 or 4 weeks' brain irradiation. The ultrastructural changes of the hippocampus were observed by electronic microscope. Results: The learning and memorizing ability of irradiation groups was significantly different from that of control group. Compared with control group, the NAA/Ct and Cho/Cr ratio in the left hippocampus in 10 Gy, 20 Gy and 30 Gy groups at 2 weeks and 4 weeks decreased significantly. Neuronal mitochondria edema, endothelial cells swelling and lamina dissociation in myelin sheath were demonstrated in various degrees by electromicroscope at 4 weeks following whole brain irradiation. Conclusions: 1 H-MRS can be used to non-invasively monitor the metabolic changes, both quantitatively and dynamically, of the irradiated rat brain, 1 H-MRS is superior to MRI in detecting early abnormality of the brain. The NAA/Cr and Cho/Cr ratio in irradiated hippocampus could reflect the severity of the brain injury to some extent. (authors)

  1. Altered expression of sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 in mouse hippocampus after kainic acid treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hoon; Jeon, Byeong Tak; Jeong, Eun Ae [Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751 (Korea, Republic of); Kim, Joon Soo; Cho, Yong Woon [Department of Neurosurgery, Masan Samsung Hospital, Sungkyunkwan University School of Medicine, Masan, Gyeongnam 630-723 (Korea, Republic of); Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung [Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751 (Korea, Republic of); Roh, Gu Seob, E-mail: anaroh@gnu.ac.kr [Department of Anatomy and Neurobiology, Institute of Health Sciences, Medical Research Center for Neural Dysfunction, Biomedical Center (BK21), Gyeongsang National University School of Medicine, Jinju, Gyeongnam 660-751 (Korea, Republic of)

    2010-03-12

    Kainic acid (KA) induces hippocampal cell death and astrocyte proliferation. There are reports that sphingosine kinase (SPHK)1 and sphingosine-1- phosphate (S1P) receptor 1 (S1P{sub 1}) signaling axis controls astrocyte proliferation. Here we examined the temporal changes of SPHK1/S1P{sub 1} in mouse hippocampus during KA-induced hippocampal cell death. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. There was an increase in Fluoro-Jade B-positive cells in the hippocampus of KA-treated mice with temporal changes of glial fibrillary acidic protein (GFAP) expression. The lowest level of SPHK1 protein expression was found 2 h after KA treatment. Six hours after KA treatment, the expression of SPHK1 and S1P{sub 1} proteins steadily increased in the hippocampus. In immunohistochemical analysis, SPHK1 and S1P{sub 1} are more immunoreactive in astrocytes within the hippocampus of KA-treated mice than in hippocampus of control mice. These results indicate that SPHK1/S1P{sub 1} signaling axis may play an important role in astrocytes proliferation during KA-induced excitotoxicity.

  2. Altered expression of sphingosine kinase 1 and sphingosine-1-phosphate receptor 1 in mouse hippocampus after kainic acid treatment

    International Nuclear Information System (INIS)

    Lee, Dong Hoon; Jeon, Byeong Tak; Jeong, Eun Ae; Kim, Joon Soo; Cho, Yong Woon; Kim, Hyun Joon; Kang, Sang Soo; Cho, Gyeong Jae; Choi, Wan Sung; Roh, Gu Seob

    2010-01-01

    Kainic acid (KA) induces hippocampal cell death and astrocyte proliferation. There are reports that sphingosine kinase (SPHK)1 and sphingosine-1- phosphate (S1P) receptor 1 (S1P 1 ) signaling axis controls astrocyte proliferation. Here we examined the temporal changes of SPHK1/S1P 1 in mouse hippocampus during KA-induced hippocampal cell death. Mice were killed at 2, 6, 24, or 48 h after KA (30 mg/kg) injection. There was an increase in Fluoro-Jade B-positive cells in the hippocampus of KA-treated mice with temporal changes of glial fibrillary acidic protein (GFAP) expression. The lowest level of SPHK1 protein expression was found 2 h after KA treatment. Six hours after KA treatment, the expression of SPHK1 and S1P 1 proteins steadily increased in the hippocampus. In immunohistochemical analysis, SPHK1 and S1P 1 are more immunoreactive in astrocytes within the hippocampus of KA-treated mice than in hippocampus of control mice. These results indicate that SPHK1/S1P 1 signaling axis may play an important role in astrocytes proliferation during KA-induced excitotoxicity.

  3. Common cuckoo females are not choosy when removing an egg during parasitism

    Czech Academy of Sciences Publication Activity Database

    Šulc, Michal; Procházka, Petr; Čapek, Miroslav; Honza, Marcel

    2016-01-01

    Roč. 27, č. 6 (2016), s. 1642-1649 ISSN 1045-2249 R&D Projects: GA ČR(CZ) GAP506/12/2404 Institutional support: RVO:68081766 Keywords : brood parasitism * coevolution * egg removal * great reed warbler * host and parasite * mimicry * reflectance * spotting pattern Subject RIV: EG - Zoology Impact factor: 3.311, year: 2016

  4. Sexy males and choosy females on exploded leks: correlates of male attractiveness in the Little Bustard.

    Science.gov (United States)

    Jiguet, Frédéric; Bretagnolle, Vincent

    2014-03-01

    In their choice of mates, females may use alternative tactics, including a comparative assessment of males in a population, using one or several relative preference criteria. Traits involved in female choice should presumably be variable between, but not within males, thus potentially providing reliable cues of male identity and quality for prospecting females. In lekking species, sexual selection is usually intense, and females can freely choose mates. Studying the Little Bustard Tetrax tetrax, a bird with an exploded lek mating system, we first identified male phenotypic traits that showed higher among, than within variation (plumage pattern, display rates and call structure). Among those and other traits (ornaments and their symmetry, body condition, lek spatial organization and territory quality), we identified phenotypic traits that correlated with male attractiveness toward females. At least four phenotypic male traits were correlated with female attraction, i.e. body condition, lek attendance, ornamental symmetry and display rates. Traits related to the initial female attraction on male territory seem to differ from traits related to the decision of females to stay in the territory of attractive males. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Meta-analysis suggests choosy females get sexy sons more than "good genes".

    Science.gov (United States)

    Prokop, Zofia M; Michalczyk, Łukasz; Drobniak, Szymon M; Herdegen, Magdalena; Radwan, Jacek

    2012-09-01

    Female preferences for specific male phenotypes have been documented across a wide range of animal taxa, including numerous species where males contribute only gametes to offspring production. Yet, selective pressures maintaining such preferences are among the major unknowns of evolutionary biology. Theoretical studies suggest that preferences can evolve if they confer genetic benefits in terms of increased attractiveness of sons ("Fisherian" models) or overall fitness of offspring ("good genes" models). These two types of models predict, respectively, that male attractiveness is heritable and genetically correlated with fitness. In this meta-analysis, we draw general conclusions from over two decades worth of empirical studies testing these predictions (90 studies on 55 species in total). We found evidence for heritability of male attractiveness. However, attractiveness showed no association with traits directly associated with fitness (life-history traits). Interestingly, it did show a positive correlation with physiological traits, which include immunocompetence and condition. In conclusion, our results support "Fisherian" models of preference evolution, while providing equivocal evidence for "good genes." We pinpoint research directions that should stimulate progress in our understanding of the evolution of female choice. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  6. Gastric stimulation in obese subjects activates the hippocampus and other regions involved in brain reward circuitry.

    Science.gov (United States)

    Wang, Gene-Jack; Yang, Julia; Volkow, Nora D; Telang, Frank; Ma, Yeming; Zhu, Wei; Wong, Christopher T; Tomasi, Dardo; Thanos, Panayotis K; Fowler, Joanna S

    2006-10-17

    The neurobiological mechanisms underlying overeating in obesity are not understood. Here, we assessed the neurobiological responses to an Implantable Gastric Stimulator (IGS), which induces stomach expansion via electrical stimulation of the vagus nerve to identify the brain circuits responsible for its effects in decreasing food intake. Brain metabolism was measured with positron emission tomography and 2-deoxy-2[18F]fluoro-D-glucose in seven obese subjects who had the IGS implanted for 1-2 years. Brain metabolism was evaluated twice during activation (on) and during deactivation (off) of the IGS. The Three-Factor Eating Questionnaire was obtained to measure the behavioral components of eating (cognitive restraint, uncontrolled eating, and emotional eating). The largest difference was in the right hippocampus, where metabolism was 18% higher (P drug craving in addicted subjects (orbitofrontal cortex, hippocampus, cerebellum, and striatum) suggests that similar brain circuits underlie the enhanced motivational drive for food and drugs seen in obese and drug-addicted subjects, respectively.

  7. Effect of Prolonged Simulated Microgravity on Metabolic Proteins in Rat Hippocampus: Steps toward Safe Space Travel.

    Science.gov (United States)

    Wang, Yun; Javed, Iqbal; Liu, Yahui; Lu, Song; Peng, Guang; Zhang, Yongqian; Qing, Hong; Deng, Yulin

    2016-01-04

    Mitochondria are not only the main source of energy in cells but also produce reactive oxygen species (ROS), which result in oxidative stress when in space. This oxidative stress is responsible for energy imbalances and cellular damage. In this study, a rat tail suspension model was used in individual experiments for 7 and 21 days to explore the effect of simulated microgravity (SM) on metabolic proteins in the hippocampus, a vital brain region involved in learning, memory, and navigation. A comparative (18)O-labeled quantitative proteomic strategy was used to observe the differential expression of metabolic proteins. Forty-two and sixty-seven mitochondrial metabolic proteins were differentially expressed after 21 and 7 days of SM, respectively. Mitochondrial Complex I, III, and IV, isocitrate dehydrogenase and malate dehydrogenase were down-regulated. Moreover, DJ-1 and peroxiredoxin 6, which defend against oxidative damage, were up-regulated in the hippocampus. Western blot analysis of proteins DJ-1 and COX 5A confirmed the mass spectrometry results. Despite these changes in mitochondrial protein expression, no obvious cell apoptosis was observed after 21 days of SM. The results of this study indicate that the oxidative stress induced by SM has profound effects on metabolic proteins.

  8. [Effects of electromagnetic radiation on RAF/MEK/ERK signaling pathway in rats hippocampus].

    Science.gov (United States)

    Zuo, Hong-yan; Wang, De-wen; Peng, Rui-yun; Wang, Shui-ming; Gao, Ya-bing; Xu, Xin-ping; Ma, Jun-Jie

    2009-05-01

    To study the development of changes for signaling molecules related to Raf/MEK/ERK pathway in hippocampus of rats after electromagnetic radiation, and investigate the mechanisms of radiation injury. Rats were exposed to X-HPM, S-HPM and EMP radiation source respectively, and animal model of electromagnetic radiation was established. Western blot was used to detect the expression of Raf-1, phosphorylated Raf-1 and phospholylated ERK. The expression of Raf-1 down-regulated during 6 h-14 d after radiation, most significantly at 7 d, and recovered at 28 d. There was no significant difference between the radiation groups. The expression of phosphorylated Raf-1 and phosphorylated ERK both up-regulated at 6 h and 7 d after radiation, more significantly at 6 h, and the two microwave groups were more serious for phosphorylated ERK. During 6 h-14 d after S-HPM radiation, the expression of phosphorylated Raf-1 increased continuously, but phosphorylated ERK changed wavily, 6 h and 7 d were expression peak. Raf/MEK/ERK signaling pathway participates in the hippocampus injury induced by electromagnetic radiation. The excessive activation of ERK pathway may result in the apoptosis and death of neurons, which is the important mechanism of recognition disfunction caused by electromagnetic radiation.

  9. Adult hippocampus derived soluble factors induce a neuronal-like phenotype in mesenchymal stem cells.

    Science.gov (United States)

    Rivera, Francisco J; Sierralta, Walter D; Minguell, Jose J; Aigner, Ludwig

    2006-10-02

    Bone marrow-derived mesenchymal stem cells (MSCs) are not restricted in their differentiation fate to cells of the mesenchymal lineage. They acquire a neural phenotype in vitro and in vivo after transplantation in the central nervous system. Here we investigated whether soluble factors derived from different brain regions are sufficient to induce a neuronal phenotype in MSCs. We incubated bone marrow-derived MSCs in conditioned medium (CM) derived from adult hippocampus (HCM), cortex (CoCM) or cerebellum (CeCM) and analyzed the cellular morphology and the expression of neuronal and glial markers. In contrast to muscle derived conditioned medium, which served as control, conditioned medium derived from the different brain regions induced a neuronal morphology and the expression of the neuronal markers GAP-43 and neurofilaments in MSCs. Hippocampus derived conditioned medium had the strongest activity. It was independent of NGF or BDNF; and it was restricted to the neuronal differentiation fate, since no induction of the astroglial marker GFAP was observed. The work indicates that soluble factors present in the brain are sufficient to induce a neuronal phenotype in MSCs.

  10. The hippocampus remains activated over the long term for the retrieval of truly episodic memories.

    Directory of Open Access Journals (Sweden)

    Caroline Harand

    Full Text Available The role of the hippocampus in declarative memory consolidation is a matter of intense debate. We investigated the neural substrates of memory retrieval for recent and remote information using functional magnetic resonance imaging (fMRI. 18 young, healthy participants learned a series of pictures. Then, during two fMRI recognition sessions, 3 days and 3 months later, they had to determine whether they recognized or not each picture using the "Remember/Know" procedure. Presentation of the same learned images at both delays allowed us to track the evolution of memories and distinguish consistently episodic memories from those that were initially episodic and then became familiar or semantic over time and were retrieved without any contextual detail. Hippocampal activation decreased over time for initially episodic, later semantic memories, but remained stable for consistently episodic ones, at least in its posterior part. For both types of memories, neocortical activations were observed at both delays, notably in the ventromedial prefrontal and anterior cingulate cortices. These activations may reflect a gradual reorganization of memory traces within neural networks. Our data indicate maintenance and strengthening of hippocampal and cortico-cortical connections in the consolidation and retrieval of episodic memories over time, in line with the Multiple Trace theory (Nadel and Moscovitch, 1997. At variance, memories becoming semantic over time consolidate through strengthening of cortico-cortical connections and progressive disengagement of the hippocampus.

  11. On initial Brain Activity Mapping of episodic and semantic memory code in the hippocampus.

    Science.gov (United States)

    Tsien, Joe Z; Li, Meng; Osan, Remus; Chen, Guifen; Lin, Longian; Wang, Phillip Lei; Frey, Sabine; Frey, Julietta; Zhu, Dajiang; Liu, Tianming; Zhao, Fang; Kuang, Hui

    2013-10-01

    It has been widely recognized that the understanding of the brain code would require large-scale recording and decoding of brain activity patterns. In 2007 with support from Georgia Research Alliance, we have launched the Brain Decoding Project Initiative with the basic idea which is now similarly advocated by BRAIN project or Brain Activity Map proposal. As the planning of the BRAIN project is currently underway, we share our insights and lessons from our efforts in mapping real-time episodic memory traces in the hippocampus of freely behaving mice. We show that appropriate large-scale statistical methods are essential to decipher and measure real-time memory traces and neural dynamics. We also provide an example of how the carefully designed, sometime thinking-outside-the-box, behavioral paradigms can be highly instrumental to the unraveling of memory-coding cell assembly organizing principle in the hippocampus. Our observations to date have led us to conclude that the specific-to-general categorical and combinatorial feature-coding cell assembly mechanism represents an emergent property for enabling the neural networks to generate and organize not only episodic memory, but also semantic knowledge and imagination. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  12. The effects of study task on prestimulus subsequent memory effects in the hippocampus.

    Science.gov (United States)

    de Chastelaine, Marianne; Rugg, Michael D

    2015-11-01

    Functional magnetic resonance imaging (fMRI) was employed to examine the effects of a study task manipulation on pre-stimulus activity in the hippocampus predictive of later successful recollection. Eighteen young participants were scanned while making either animacy or syllable judgments on visually presented study words. Cues presented before each word denoted which judgment should be made. Following the study phase, a surprise recognition memory test was administered in which each test item had to be endorsed as "Remembered," "Known," or "New." As expected, "deep" animacy judgments led to better memory for study items than did "shallow" syllable judgments. In both study tasks, pre-stimulus subsequent recollection effects were evident in the interval between the cue and the study item in bilateral anterior hippocampus. However, the direction of the effects differed according to the study task: whereas pre-stimulus hippocampal activity on animacy trials was greater for later recollected items than items judged old on the basis of familiarity (replicating prior findings), these effects reversed for syllable trials. We propose that the direction of pre-stimulus hippocampal subsequent memory effects depends on whether an optimal pre-stimulus task set facilitates study processing that is conducive or unconducive to the formation of contextually rich episodic memories. © 2015 Wiley Periodicals, Inc.

  13. Characterizing context-dependent differential firing activity in the hippocampus and entorhinal cortex.

    Science.gov (United States)

    Prerau, Michael J; Lipton, Paul A; Eichenbaum, Howard B; Eden, Uri T

    2014-04-01

    The rat hippocampus and entorhinal cortex have been shown to possess neurons with place fields that modulate their firing properties under different behavioral contexts. Such context-dependent changes in neural activity are commonly studied through electrophysiological experiments in which a rat performs a continuous spatial alternation task on a T-maze. Previous research has analyzed context-based differential firing during this task by describing differences in the mean firing activity between left-turn and right-turn experimental trials. In this article, we develop qualitative and quantitative methods to characterize and compare changes in trial-to-trial firing rate variability for sets of experimental contexts. We apply these methods to cells in the CA1 region of hippocampus and in the dorsocaudal medial entorhinal cortex (dcMEC), characterizing the context-dependent differences in spiking activity during spatial alternation. We identify a subset of cells with context-dependent changes in firing rate variability. Additionally, we show that dcMEC populations encode turn direction uniformly throughout the T-maze stem, whereas CA1 populations encode context at major waypoints in the spatial trajectory. Our results suggest scenarios in which individual cells that sparsely provide information on turn direction might combine in the aggregate to produce a robust population encoding. Copyright © 2014 Wiley Periodicals, Inc.

  14. A Novel Method to Identify Differential Pathways in Hippocampus Alzheimer's Disease.

    Science.gov (United States)

    Liu, Chun-Han; Liu, Lian

    2017-05-08

    BACKGROUND Alzheimer's disease (AD) is the most common type of dementia. The objective of this paper is to propose a novel method to identify differential pathways in hippocampus AD. MATERIAL AND METHODS We proposed a combined method by merging existed methods. Firstly, pathways were identified by four known methods (DAVID, the neaGUI package, the pathway-based co-expressed method, and the pathway network approach), and differential pathways were evaluated through setting weight thresholds. Subsequently, we combined all pathways by a rank-based algorithm and called the method the combined method. Finally, common differential pathways across two or more of five methods were selected. RESULTS Pathways obtained from different methods were also different. The combined method obtained 1639 pathways and 596 differential pathways, which included all pathways gained from the four existing methods; hence, the novel method solved the problem of inconsistent results. Besides, a total of 13 common pathways were identified, such as metabolism, immune system, and cell cycle. CONCLUSIONS We have proposed a novel method by combining four existing methods based on a rank product algorithm, and identified 13 significant differential pathways based on it. These differential pathways might provide insight into treatment and diagnosis of hippocampus AD.

  15. Theta variation and spatiotemporal scaling along the septotemporal axis of the hippocampus

    Directory of Open Access Journals (Sweden)

    Lauren L Long

    2015-03-01

    Full Text Available Hippocampal theta has been related to locomotor speed, attention, anxiety, sensorimotor integration and memory among other emergent phenomena. One difficulty in understanding the function of theta is that the hippocampus (HPC modulates voluntary behavior at the same time that it processes sensory input. Both functions are correlated with characteristic changes in theta indices. The current review highlights a series of studies examining theta local field potential (LFP signals across the septotemporal or longitudinal axis of the HPC. While the theta signal is coherent throughout the entirety of the HPC, the amplitude, but not the frequency, of theta varies significantly across its three-dimensional expanse. We suggest that the theta signal offers a rich vein of information about how distributed neuronal ensembles support emergent function. Further, we speculate that emergent function across the long axis varies with respect to spatiotemporal scale. Thus, septal hippocampus processes details of the proximal spatiotemporal environment while more temporal aspects process larger spaces and wider time-scales. The degree to which emergent functions are supported by the synchronization of theta across the septotemporal axis is an open question. Our working model is that theta synchrony serves to bind ensembles representing varying resolutions of spatiotemporal information at interdependent septotemporal areas of the HPC. Such synchrony and cooperative interactions along the septotemporal axis likely support memory formation and subsequent consolidation and retrieval.

  16. A NEUROPHENOMENOLOGICAL MODEL FOR THE ROLE OF THE HIPPOCAMPUS IN TEMPORAL CONSCIOUSNES. EVIDENCE FROM CONFABULATION

    Directory of Open Access Journals (Sweden)

    Gianfranco eDalla Barba

    2015-08-01

    Full Text Available Confabulation, the production of statements or actions that are unintentionally incongruous to the subject’s history, background, present and future situation, is a rather infrequent disorder with different aetiologies and anatomical lesions. Although they may differ in many ways, confabulations show major similarities. Their content, with some minor exceptions, is plausible and therefore indistinguishable from true memories, unless one is familiar with the patient's history, background, present and future situation. They extend through the whole individuals’ temporality, including their past, present and future. Accordingly, we have proposed that rather than a mere memory disorder; confabulation reflects a distortion of Temporal Consciousness, i.e. a specific form of consciousness that allows individuals to locate objects and events according to their subjective temporality. Another feature that confabulators share is that, regardless of their lesion's location, they all have a relatively preserved hippocampus, at least unilaterally. In this article, we review data showing differences and similarities among forms of confabulation. We then describe a model showing that the hippocampus is crucial both for the normal functioning of Temporal Consciousness and as the generator of confabulations, and that different types of confabulation can be traced back to a distortion of Temporal Consciousness resulting from damage or

  17. [The clinico-neuropsychological aspects of arteriovenous malformations of the hippocampus].

    Science.gov (United States)

    Buklina, S B; Filatov, Iu M; Eliava, Sh Sh

    1998-01-01

    A comprehensive examination was made in 39 patients with arteriovenous malformations (AVM) of hippocampus. Prior to and following surgery, all the patients underwent neuropsychological study after A. R. Luriia (1962). Mnestic disorder was found to be the most common abnormality in patients with AVM at this site. Before surgery, they were detected in 34 of 39 patients, 11 of them having severe memory disorders with the traits of the Korsakoff's syndrome. These patients were found to have mixed posthemorrhagic lesion of the hippocampus, other portions of the temporal lobe and periventricular structures. Twenty nine patients were operated on, 14 of them had progressive mnestic disorder of the modally nonspecific type irrespective the side operated on. There were no postoperative Korsakoff's syndromes. There was no progression in memory defects in patients after surgery on the brain drastically changed after hemorrhage or removal of minor malformations. Before hemorrhage, epileptic paroxysms were observed in 2 of the 39 patients only in the presence of massive AVM obligatorily involving the temporal cortex. Following surgery, there were no new epileptic paroxysms and changes in the emotional status and motivations in the patients. Thus, the hippocampal formation is involved in the primary mechanisms of fixation, retention, reproduction of a memory trace. The participation of many structures of the brain is required to form an emotional status, motivation, and clinical manifestations of epileptic activity.

  18. Acetylcholine release in the hippocampus during the operant conditioned reflex and the footshock stimulus in rats.

    Science.gov (United States)

    Dong, Yu; Mao, Jianjun; Shangguan, Dihua; Zhao, Rui; Liu, Guoquan

    2004-10-14

    The activity of the septo-hippocampal cholinergic pathway was investigated by measuring changes in the extracellular acetylcholine (ACh) levels in the hippocampus, by means of microdialysis, during the operant conditioned reflex and the repeated footshock stimulus. Microdialysis samplings were conducted in a Skinner box where lights were delivered as conditioned stimuli (CS) paired with footshocks as unconditioned stimuli (US). Two groups of rats were used. Extracellular ACh and choline (Ch) in samples collected at 6min intervals were assessed by high-performance liquid chromatography with electrochemical detection. The elevation of hippocampus ACh was observed in the two experimental groups. The increase in ACh during aversive stimulus (footshock) was significantly larger and was probably related to the number of footshocks. There might be moderate increase in the hippocampal ACh release during the retrieval of information. The concentration of choline showed no significant fluctuation in the two groups during the whole process. This experiment explored in more detail hippocampal cholinergic activity in relation to the two different procedures.

  19. Hippocampus shape analysis for temporal lobe epilepsy detection in magnetic resonance imaging

    Science.gov (United States)

    Kohan, Zohreh; Azmi, Reza

    2016-03-01

    There are evidences in the literature that Temporal Lobe Epilepsy (TLE) causes some lateralized atrophy and deformation on hippocampus and other substructures of the brain. Magnetic Resonance Imaging (MRI), due to high-contrast soft tissue imaging, is one of the most popular imaging modalities being used in TLE diagnosis and treatment procedures. Using an algorithm to help clinicians for better and more effective shape deformations analysis could improve the diagnosis and treatment of the disease. In this project our purpose is to design, implement and test a classification algorithm for MRIs based on hippocampal asymmetry detection using shape and size-based features. Our method consisted of two main parts; (1) shape feature extraction, and (2) image classification. We tested 11 different shape and size features and selected four of them that detect the asymmetry in hippocampus significantly in a randomly selected subset of the dataset. Then, we employed a support vector machine (SVM) classifier to classify the remaining images of the dataset to normal and epileptic images using our selected features. The dataset contains 25 patient images in which 12 cases were used as a training set and the rest 13 cases for testing the performance of classifier. We measured accuracy, specificity and sensitivity of, respectively, 76%, 100%, and 70% for our algorithm. The preliminary results show that using shape and size features for detecting hippocampal asymmetry could be helpful in TLE diagnosis in MRI.

  20. Acetylcholinesterase inhibitors rapidly activate Trk neurotrophin receptors in the mouse hippocampus

    Science.gov (United States)

    Autio, Henri; Mätlik, Kert; Rantamäki, Tomi; Lindemann, Lothar; Hoener, Marius C; Chao, Moses; Arumäe, Urmas; Castrén, Eero

    2014-01-01

    Acetylcholinesterase inhibitors are first-line therapies for Alzheimer's disease. These drugs increase cholinergic tone in the target areas of the cholinergic neurons of the basal forebrain. Basal forebrain cholinergic neurons are dependent upon trophic support by nerve growth factor (NGF) through its neurotrophin receptor, TrkA. In the present study, we investigated whether the acetylcholinesterase inhibitors donepezil and galantamine could influence neurotrophin receptor signaling in the brain. Acute administration of donepezil (3 mg/kg, i.p.) led to the rapid autophosphorylation of TrkA and TrkB neurotrophin receptors in the adult mouse hippocampus. Similarly, galantamine dose-dependently (3, 9 mg/kg, i.p.) increased TrkA and TrkB phosphorylation in the mouse hippocampus. Both treatments also increased the phosphorylation of transcription factor CREB and tended to increase the phosphorylation of AKT kinase but did not alter the activity of MAPK42/44. Chronic treatment with galantamine (3 mg/kg, i.p., 14 days), did not induce changes in hippocampal NGF and BDNF synthesis or protein levels. Our findings show that acetylcholinesterase inhibitors are capable of rapidly activating hippocampal neurotrophin signaling and thus suggest that therapies targeting Trk signaling may already be in clinical use in the treatment of AD. PMID:21820453

  1. Independent delta/theta rhythms in the human hippocampus and entorhinal cortex

    Directory of Open Access Journals (Sweden)

    Florian Mormann

    2008-05-01

    Full Text Available Theta oscillations in the medial temporal lobe (MTL of mammals are involved in various functions such as spatial navigation, sensorimotor integration, and cognitive processing. While the theta rhythm was originally assumed to originate in the medial septum, more recent studies suggest autonomous theta generation in the MTL. Although coherence between entorhinal and hippocampal theta activity has been found to influence memory formation, it remains unclear whether these two structures can generate theta independently. In this study we analyzed intracranial electroencephalographic (EEG recordings from 22 patients with unilateral hippocampal sclerosis undergoing presurgical evaluation prior to resection of the epileptic focus. Using a wavelet-based, frequency-band-specific measure of phase synchronization, we quantified synchrony between 10 different recording sites along the longitudinal axis of the hippocampal formation in the non-epileptic brain hemisphere. We compared EEG synchrony between adjacent recording sites (i within the entorhinal cortex, (ii within the hippocampus, and (iii between the hippocampus and entorhinal cortex. We observed a significant interregional gap in synchrony for the delta and theta band, indicating the existence of independent delta/theta rhythms in different subregions of the human MTL. The interaction of these rhythms could represent the temporal basis for the information processing required for mnemonic encoding and retrieval.

  2. Genetic Diversity of Three Spotted Seahorse, Hippocampus trimaculatus (Leach, 1814 in India Using Four Microsatellite Loci

    Directory of Open Access Journals (Sweden)

    Muthusamy THANGARAJ

    2012-11-01

    Full Text Available Seahorse populations are declining year by year not only in India but also throughout the world, because of over-fishing and increasing demand in Chinese market. The three spotted seahorse, Hippocampus trimaculatus is one of the dominant species and distributed all along the Indian coast. To study the genetic structure is very essential to conserve these species effectively. Hippocampus trimaculatus samples (n = 60/population were collected from Mullimunai in Palk Bay, Tuticorin in Gulf of Mannar and Vizhinjam in south Malabar in India as by-catch in small trawlnets. Microsatellites are being widely applied in animal genome mapping and phylogenetic analysis because of their co-dominant inheritance and high degree of polymorphism. The molecular polymorphism of microsatellite DNA has proved to be a potent tool in the analysis of several aspects of population genetics. In the present study, four microsatellite primers were used to investigate the genetic difference and structure of three selected populations of H. trimaculatus. The result showed the overall FST value (0.0989 of the microsatellite loci between Mullimunai and Vizhinjam was significantly different. The genetic distance between Mullimunai and Tuticorin was 0.183; between Tuticorin and Vizhinjam was 0.461; and Mullimunai and Vizhinjam was 0.837. There was no statistical evidence of recent severe bottlenecks in any of the three populations. Continuous monitoring of microsatellite variations within the populations of all the three locations was suggested to determine whether genetic variation within the populations is stabilized between year classes.

  3. Altered Effective Connectivity of Hippocampus-Dependent Episodic Memory Network in mTBI Survivors

    Directory of Open Access Journals (Sweden)

    Hao Yan

    2016-01-01

    Full Text Available Traumatic brain injuries (TBIs are generally recognized to affect episodic memory. However, less is known regarding how external force altered the way functionally connected brain structures of the episodic memory system interact. To address this issue, we adopted an effective connectivity based analysis, namely, multivariate Granger causality approach, to explore causal interactions within the brain network of interest. Results presented that TBI induced increased bilateral and decreased ipsilateral effective connectivity in the episodic memory network in comparison with that of normal controls. Moreover, the left anterior superior temporal gyrus (aSTG, the concept forming hub, left hippocampus (the personal experience binding hub, and left parahippocampal gyrus (the contextual association hub were no longer network hubs in TBI survivors, who compensated for hippocampal deficits by relying more on the right hippocampus (underlying perceptual memory and the right medial frontal gyrus (MeFG in the anterior prefrontal cortex (PFC. We postulated that the overrecruitment of the right anterior PFC caused dysfunction of the strategic component of episodic memory, which caused deteriorating episodic memory in mTBI survivors. Our findings also suggested that the pattern of brain network changes in TBI survivors presented similar functional consequences to normal aging.

  4. Cerebral cortex and hippocampus respond differently after post-natal exposure to uranium

    International Nuclear Information System (INIS)

    Lestaevel, Philippe; Bensoussan, Hélène; Dhieux, Bernadette; Delissen, Olivia; Dublineau, Isabelle; Voisin, Philippe; Vacher, Claire-Marie; Taouis, Mohammed

    2013-01-01

    The central nervous system (CNS) is known to be sensitive to pollutants during its development. Uranium (U) is a heavy metal that occurs naturally in the environment as a component of the earth's crust, and populations may therefore be chronically exposed to U through drinking water and food. Previous studies have shown that the CNS is a target of U in rats exposed in adulthood. We assessed the effects of U on behavior and cholinergic system of rats exposed from birth for 10 weeks at 10 mg.L"-"1 or 40 mg.L"-"1. For behavioral analysis, the sleep/wake cycle (recorded by telemetry), the object recognition memory and the spatial working memory (Y-maze) were evaluated. Acetylcholine (ACh) and acetylcholinesterase (AChE) levels were evaluated in the entorhinal cortex and hippocampus. At 40 mg.L"-"1, U exposure impaired object recognition memory (-20%), but neither spatial working memory nor the sleep/wake cycle was impaired. A significant decrease was observed in both the ACh concentration (-14%) and AChE activity (-14%) in the entorhinal cortex, but not in the hippocampus. Any significant effect on behaviour and cholinergic system was observed at 10 mg U.L"-"1. These results demonstrate that early exposure to U during postnatal life induces a structure cerebral-dependant cholinergic response and modifies such memory process in rats. This exposure to U early in life could have potential delayed effects in adulthood. (author)

  5. Lanthanum chloride impairs spatial memory through ERK/MSK1 signaling pathway of hippocampus in rats.

    Science.gov (United States)

    Liu, Huiying; Yang, Jinghua; Liu, Qiufang; Jin, Cuihong; Wu, Shengwen; Lu, Xiaobo; Zheng, Linlin; Xi, Qi; Cai, Yuan

    2014-12-01

    Rare earth elements (REEs) are used in many fields for their diverse physical and chemical properties. Surveys have shown that REEs can impair learning and memory in children and cause neurobehavioral defects in animals. However, the mechanism underlying these impairments has not yet been completely elucidated. Lanthanum (La) is often selected to study the effects of REEs. The aim of this study was to investigate the spatial memory impairments induced by lanthanum chloride (LaCl3) and the probable underlying mechanism. Wistar rats were exposed to LaCl3 in drinking water at 0 % (control, 0 mM), 0.25 % (18 mM), 0.50 % (36 mM), and 1.00 % (72 mM) from birth to 2 months after weaning. LaCl3 considerably impaired the spatial learning and memory of rats in the Morris water maze test, damaged the synaptic ultrastructure and downregulated the expression of p-MEK1/2, p-ERK1/2, p-MSK1, p-CREB, c-FOS and BDNF in the hippocampus. These results indicate that LaCl3 exposure impairs the spatial learning and memory of rats, which may be attributed to disruption of the synaptic ultrastructure and inhibition of the ERK/MSK1 signaling pathway in the hippocampus.

  6. Extensive training and hippocampus or striatum lesions: effect on place and response strategies.

    Science.gov (United States)

    Jacobson, Tara K; Gruenbaum, Benjamin F; Markus, Etan J

    2012-02-01

    The hippocampus has been linked to spatial navigation and the striatum to response learning. The current study focuses on how these brain regions continue to interact when an animal is very familiar with the task and the environment and must continuously switch between navigation strategies. Rats were trained to solve a plus maze using a place or a response strategy on different trials within a testing session. A room cue (illumination) was used to indicate which strategy should be used on a given trial. After extensive training, animals underwent dorsal hippocampus, dorsal lateral striatum or sham lesions. As expected hippocampal lesions predominantly caused impairment on place but not response trials. Striatal lesions increased errors on both place and response trials. Competition between systems was assessed by determining error type. Pre-lesion and sham animals primarily made errors to arms associated with the wrong (alternative) strategy, this was not found after lesions. The data suggest a qualitative change in the relationship between hippocampal and striatal systems as a task is well learned. During acquisition the two systems work in parallel, competing with each other. After task acquisition, the two systems become more integrated and interdependent. The fact that with extensive training (as something becomes a "habit"), behaviors become dependent upon the dorsal lateral striatum has been previously shown. The current findings indicate that dorsal lateral striatum involvement occurs even when the behavior is spatial and continues to require hippocampal processing. Published by Elsevier Inc.

  7. BDNF expression in the hippocampus of maternally separated rats: does Bifidobacterium breve 6330 alter BDNF levels?

    Science.gov (United States)

    O'Sullivan, E; Barrett, E; Grenham, S; Fitzgerald, P; Stanton, C; Ross, R P; Quigley, E M M; Cryan, J F; Dinan, T G

    2011-09-01

    Brain-derived neurotrophic factor (BDNF) is of interest because of its putative role in stress and psychiatric disorders. Maternal separation is used as an animal model of early-life stress and of irritable bowel syndrome (IBS). Animals exposed to the paradigm show altered gut function together with heightened levels of arousal and corticosterone. Some probiotic organisms have been shown to be of benefit in IBS and influence the brain-gut axis. Our objective was to investigate the effects of maternal separation on BDNF under basal conditions and in response to the probiotic Bifidobacterium breve 6330. The study implemented the maternal separation model which we have previously described. Polymerase chain reaction and in situ hybridisation were performed to measure the effect of maternal separation on both BDNF total variants and BDNF splice variant (exon) IV in the hippocampus. Maternally separated and non-separated rats were treated with B. breve 6330, to investigate the effect of this probiotic on BDNF total variant and BDNF exon IV expression. Maternal separation increased BDNF total variants (Pbreve 6330 increased BDNF total variants (Pbreve 6330 did not alter BDNF levels in the maternally separated rats. Maternal separation caused a marked increase in BDNF in the hippocampus. While B. breve 6330 influenced BDNF in normal animals, it had no significant effect on BDNF in those which were maternally separated. We have demonstrated that an orally administered probiotic can influence hippocampal BDNF.

  8. Characterization, scaling, and partial representation of diffuse and discrete input junctions to CA3 hippocampus.

    Science.gov (United States)

    Ascarrunz, F G; Kisley, M A; Flach, K A; Hamilton, R W; MacGregor, R J

    1995-07-01

    This paper applies a general mathematical system for characterizing and scaling functional connectivity and information flow across the diffuse (EC) and discrete (DG) input junctions to the CA3 hippocampus. Both gross connectivity and coordinated multiunit informational firing patterns are quantitatively characterized in terms of 32 defining parameters interrelated by 17 equations, and then scaled down according to rules for uniformly proportional scaling and for partial representation. The diffuse EC-CA3 junction is shown to be uniformly scalable with realistic representation of both essential spatiotemporal cooperativity and coordinated firing patterns down to populations of a few hundred neurons. Scaling of the discrete DG-CA3 junction can be effected with a two-step process, which necessarily deviates from uniform proportionality but nonetheless produces a valuable and readily interpretable reduced model, also utilizing a few hundred neurons in the receiving population. Partial representation produces a reduced model of only a portion of the full network where each model neuron corresponds directly to a biological neuron. The mathematical analysis illustrated here shows that although omissions and distortions are inescapable in such an application, satisfactorily complete and accurate models the size of pattern modules are possible. Finally, the mathematical characterization of these junctions generates a theory which sees the DG as a definer of the fine structure of embedded traces in the hippocampus and entire coordinated patterns of sequences of 14-cell links in CA3 as triggered by the firing of sequences of individual neurons in DG.

  9. Evidences of the role of the rodent hippocampus in the non-spatial recognition memory.

    Science.gov (United States)

    Yi, Jee Hyun; Park, Hye Jin; Kim, Byeong C; Kim, Dong Hyun; Ryu, Jong Hoon

    2016-01-15

    The hippocampus is a key region responsible for processing spatial information. However, the role of the hippocampus in non-spatial recognition memory is still controversial. In the present study, we performed hippocampal lesioning to address this controversy. The hippocampi of mice were disrupted with bilateral cytotoxic lesions, and standard object recognition (non-spatial) and object location recognition (spatial) were tested. In the habituation period, mice with hippocampal lesions needed a significantly longer time to fully habituate to the test box. Interestingly, after 4 days of habituation (insufficient habituation), the recognition index was similar in the sham and hippocampal lesion groups. However, exploration time was significantly shorter in mice with hippocampal lesions compared with that in control mice. Interestingly, if mice were subjected to a 10-days-long period of habituation (full habituation), the recognition index was significantly lower in mice with hippocampal lesions compared with that in control mice; however, total exploration time was similar in both groups. Furthermore, the object recognition test after full habituation occluded hippocampal long-term potentiation, a cellular model of memory. These results indicate that sufficient habituation is required to observe the effects of hippocampal lesions on object recognition memory. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Focal adhesion kinase regulates neuronal growth, synaptic plasticity and hippocampus-dependent spatial learning and memory.

    Science.gov (United States)

    Monje, Francisco J; Kim, Eun-Jung; Pollak, Daniela D; Cabatic, Maureen; Li, Lin; Baston, Arthur; Lubec, Gert

    2012-01-01

    The focal adhesion kinase (FAK) is a non-receptor tyrosine kinase abundantly expressed in the mammalian brain and highly enriched in neuronal growth cones. Inhibitory and facilitatory activities of FAK on neuronal growth have been reported and its role in neuritic outgrowth remains controversial. Unlike other tyrosine kinases, such as the neurotrophin receptors regulating neuronal growth and plasticity, the relevance of FAK for learning and memory in vivo has not been clearly defined yet. A comprehensive study aimed at determining the role of FAK in neuronal growth, neurotransmitter release and synaptic plasticity in hippocampal neurons and in hippocampus-dependent learning and memory was therefore undertaken using the mouse model. Gain- and loss-of-function experiments indicated that FAK is a critical regulator of hippocampal cell morphology. FAK mediated neurotrophin-induced neuritic outgrowth and FAK inhibition affected both miniature excitatory postsynaptic potentials and activity-dependent hippocampal long-term potentiation prompting us to explore the possible role of FAK in spatial learning and memory in vivo. Our data indicate that FAK has a growth-promoting effect, is importantly involved in the regulation of the synaptic function and mediates in vivo hippocampus-dependent spatial learning and memory. Copyright © 2011 S. Karger AG, Basel.

  11. Spontaneous revisitation during visual exploration as a link among strategic behavior, learning, and the hippocampus.

    Science.gov (United States)

    Voss, Joel L; Warren, David E; Gonsalves, Brian D; Federmeier, Kara D; Tranel, Dan; Cohen, Neal J

    2011-08-02

    Effective exploratory behaviors involve continuous updating of sensory sampling to optimize the efficacy of information gathering. Despite some work on this issue in animals, little information exists regarding the cognitive or neural mechanisms for this sort of behavioral optimization in humans. Here we examined a visual exploration phenomenon that occurred when human subjects studying an array of objects spontaneously looked "backward" in their scanning paths to view recently seen objects again. This "spontaneous revisitation" of recently viewed objects was associated with enhanced hippocampal activity and superior subsequent memory performance in healthy participants, but occurred only rarely in amnesic patients with severe damage to the hippocampus. These findings demonstrate the necessity of the hippocampus not just in the aspects of long-term memory with which it has been associated previously, but also in the short-term adaptive control of behavior. Functional neuroimaging showed hippocampal engagement occurring in conjunction with frontocerebellar circuits, thereby revealing some of the larger brain circuitry essential for the strategic deployment of information-seeking behaviors that optimize learning.

  12. Tranquilizing and Allaying Excitement Needling Method Affects BDNF and SYP Expression in Hippocampus

    Directory of Open Access Journals (Sweden)

    Peng Zheng

    2017-01-01

    Full Text Available Sleep disorder is a state of sleep loss caused by various reasons, which leads to a series of changes, such as emotion, learning and memory, and immune function. “Tranquilizing and allaying excitement” was widely used in clinical treatment of insomnia; however, the mechanism was still not very clear. We randomly divided rats into three groups: control group, sleep deprivation group, and acupuncture treatment group. We observed BDNF and SYP expression in hippocampus in these three groups. Both protein contents and mRNA contents of BDNF and SYP were measured by western blot, immunohistochemistry, and RT-PCR analysis. The sleep deprivation model was established using modified multiple platform sleep deprivation method (MMPM. Our study explored the BDNF and SYP abnormality in hippocampus caused by sleep deprivation and “tranquilizing and allaying excitement” intervention regulated the abnormal expression of BDNF and SYP caused by sleep deprivation on the short run and the long run. Our study provided a molecular evidence that “tranquilizing and allaying excitement” treatment in rats with sleep disorder affects learning and memory ability.

  13. Methamphetamine reduces LTP and increases baseline synaptic transmission in the CA1 region of mouse hippocampus.

    Directory of Open Access Journals (Sweden)

    Jarod Swant

    2010-06-01

    Full Text Available Methamphetamine (METH is an addictive psychostimulant whose societal impact is on the rise. Emerging evidence suggests that psychostimulants alter synaptic plasticity in the brain--which may partly account for their adverse effects. While it is known that METH increases the extracellular concentration of monoamines dopamine, serotonin, and norepinephrine, it is not clear how METH alters glutamatergic transmission. Within this context, the aim of the present study was to investigate the effects of acute and systemic METH on basal synaptic transmission and long-term potentiation (LTP; an activity-induced increase in synaptic efficacy in CA1 sub-field in the hippocampus. Both the acute ex vivo application of METH to hippocampal slices and systemic administration of METH decreased LTP. Interestingly, the acute ex vivo application of METH at a concentration of 30 or 60 microM increased baseline synaptic transmission as well as decreased LTP. Pretreatment with eticlopride (D2-like receptor antagonist did not alter the effects of METH on synaptic transmission or LTP. In contrast, pretreatment with D1/D5 dopamine receptor antagonist SCH23390 or 5-HT1A receptor antagonist NAN-190 abrogated the effect of METH on synaptic transmission. Furthermore, METH did not increase baseline synaptic transmission in D1 dopamine receptor haploinsufficient mice. Our findings suggest that METH affects excitatory synaptic transmission via activation of dopamine and serotonin receptor systems in the hippocampus. This modulation may contribute to synaptic maladaption induced by METH addiction and/or METH-mediated cognitive dysfunction.

  14. Radiation Damage to Nervous System: Designing Optimal Models for Realistic Neuron Morphology in Hippocampus

    Science.gov (United States)

    Batmunkh, Munkhbaatar; Bugay, Alexander; Bayarchimeg, Lkhagvaa; Lkhagva, Oidov

    2018-02-01

    The present study is focused on the development of optimal models of neuron morphology for Monte Carlo microdosimetry simulations of initial radiation-induced events of heavy charged particles in the specific types of cells of the hippocampus, which is the most radiation-sensitive structure of the central nervous system. The neuron geometry and particles track structures were simulated by the Geant4/Geant4-DNA Monte Carlo toolkits. The calculations were made for beams of protons and heavy ions with different energies and doses corresponding to real fluxes of galactic cosmic rays. A simple compartmental model and a complex model with realistic morphology extracted from experimental data were constructed and compared. We estimated the distribution of the energy deposition events and the production of reactive chemical species within the developed models of CA3/CA1 pyramidal neurons and DG granule cells of the rat hippocampus under exposure to different particles with the same dose. Similar distributions of the energy deposition events and concentration of some oxidative radical species were obtained in both the simplified and realistic neuron models.

  15. Neuroprotective actions of the synthetic estrogen 17alpha-ethynylestradiol in the hippocampus.

    Science.gov (United States)

    Picazo, Ofir; Becerril-Montes, Adriana; Huidobro-Perez, Delia; Garcia-Segura, Luis M

    2010-07-01

    17alpha-ethynylestradiol (EE2), a major constituent of many oral contraceptives, is similar in structure to 17beta-estradiol, which has neuroprotective properties in several animal models. This study explored the potential neuroprotective actions of EE2 against kainic and quinolinic acid toxicity in the hippocampus of adult ovariectomized Wistar rats. A decrease in the number of Nissl-stained neurons and the induction of vimentin immunoreactivity in astrocytes was observed in the hilus of the dentate gyrus of the hippocampus after the administration of either kainic acid or quinolinic acid. EE2 prevented the neuronal loss and the induction of vimentin immunoreactivity induced by kainic acid at low (1 microg/rat) and high (10-100 microg/rat) doses and exerted a protection against quinolinic acid toxicity at a low dose (1 microg/rat) only. These observations demonstrate that EE2 exerts neuroprotective actions against excitotoxic insults. This finding is relevant for the design of new neuroprotective estrogenic compounds.

  16. Combined histochemical staining, RNA amplification, regional, and single cell cDNA analysis within the hippocampus.

    Science.gov (United States)

    Ginsberg, Stephen D; Che, Shaoli

    2004-08-01

    The use of five histochemical stains (cresyl violet, thionin, hematoxylin & eosin, silver stain, and acridine orange) was evaluated in combination with an expression profiling paradigm that included regional and single cell analyses within the hippocampus of post-mortem human brains and adult mice. Adjacent serial sections of human and mouse hippocampus were labeled by histochemistry or neurofilament immunocytochemistry. These tissue sections were used as starting material for regional and single cell microdissection followed by a newly developed RNA amplification procedure (terminal continuation (TC) RNA amplification) and subsequent hybridization to custom-designed cDNA arrays. Results indicated equivalent levels of global hybridization signal intensity and relative expression levels for individual genes for hippocampi stained by cresyl violet, thionin, and hematoxylin & eosin, and neurofilament immunocytochemistry. Moreover, no significant differences existed between the Nissl stains and neurofilament immunocytochemistry for individual CA1 neurons obtained via laser capture microdissection. In contrast, a marked decrement was observed in adjacent hippocampal sections stained for silver stain and acridine orange, both at the level of the regional dissection and at the CA1 neuron population level. Observations made on the cDNA array platform were validated by real-time qPCR using primers directed against beta-actin and glyceraldehyde-3 phosphate dehydrogenase. Thus, this report demonstrated the utility of using specific Nissl stains, but not stains that bind RNA species directly, in both human and mouse brain tissues at the regional and cellular level for state-of-the-art molecular fingerprinting studies.

  17. Aspartic acid in the hippocampus: a biomarker for postoperative cognitive dysfunction.

    Science.gov (United States)

    Hu, Rong; Huang, Dong; Tong, Jianbin; Liao, Qin; Hu, Zhonghua; Ouyang, Wen

    2014-01-15

    This study established an aged rat model of cognitive dysfunction using anesthesia with 2% isoflurane and 80% oxygen for 2 hours. Twenty-four hours later, Y-maze test results showed that isoflurane significantly impaired cognitive function in aged rats. Gas chromatography-mass spectrometry results showed that isoflurane also significantly increased the levels of N,N-diethylacetamide, n-ethylacetamide, aspartic acid, malic acid and arabinonic acid in the hippocampus of isoflurane-treated rats. Moreover, aspartic acid, N,N-diethylacetamide, n-ethylacetamide and malic acid concentration was positively correlated with the degree of cognitive dysfunction in the isoflurane-treated rats. It is evident that hippocampal metabolite changes are involved in the formation of cognitive dysfunction after isoflurane anesthesia. To further verify these results, this study cultured hippocampal neurons in vitro, which were then treated with aspartic acid (100 μmol/L). Results suggested that aspartic acid concentration in the hippocampus may be a biomarker for predicting the occurrence and disease progress of cognitive dysfunction.

  18. Segmentation of the hippocampus by transferring algorithmic knowledge for large cohort processing.

    Science.gov (United States)

    Thyreau, Benjamin; Sato, Kazunori; Fukuda, Hiroshi; Taki, Yasuyuki

    2018-01-01

    The hippocampus is a particularly interesting target for neuroscience research studies due to its essential role within the human brain. In large human cohort studies, bilateral hippocampal structures are frequently identified and measured to gain insight into human behaviour or genomic variability in neuropsychiatric disorders of interest. Automatic segmentation is performed using various algorithms, with FreeSurfer being a popular option. In this manuscript, we present a method to segment the bilateral hippocampus using a deep-learned appearance model. Deep convolutional neural networks (ConvNets) have shown great success in recent years, due to their ability to learn meaningful features from a mass of training data. Our method relies on the following key novelties: (i) we use a wide and variable training set coming from multiple cohorts (ii) our training labels come in part from the output of the FreeSurfer algorithm, and (iii) we include synthetic data and use a powerful data augmentation scheme. Our method proves to be robust, and it has fast inference (deep neural-network methods can easily encode, and even improve, existing anatomical knowledge, even when this knowledge exists in algorithmic form. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Hippocampus activation related to 'real-time' processing of visuospatial change.

    Science.gov (United States)

    Beudel, M; Leenders, K L; de Jong, B M

    2016-12-01

    The delay associated with cerebral processing time implies a lack of real-time representation of changes in the observed environment. To bridge this gap for motor actions in a dynamical environment, the brain uses predictions of the most plausible future reality based on previously provided information. To optimise these predictions, adjustments to actual experiences are necessary. This requires a perceptual memory buffer. In our study we gained more insight how the brain treats (real-time) information by comparing cerebral activations related to judging past-, present- and future locations of a moving ball, respectively. Eighteen healthy subjects made these estimations while fMRI data was obtained. All three conditions evoked bilateral dorsal-parietal and premotor activations, while judgment of the location of the ball at the moment of judgment showed increased bilateral posterior hippocampus activation relative to making both future and past judgments at the one-second time-sale. Since the condition of such 'real-time' judgments implied undistracted observation of the ball's actual movements, the associated hippocampal activation is consistent with the concept that the hippocampus participates in a top-down exerted sensory gating mechanism. In this way, it may play a role in novelty (saliency) detection. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Effect of zinc supplementation on neuronal precursor proliferation in the rat hippocampus after traumatic brain injury.

    Science.gov (United States)

    Cope, Elise C; Morris, Deborah R; Gower-Winter, Shannon D; Brownstein, Naomi C; Levenson, Cathy W

    2016-05-01

    There is great deal of debate about the possible role of adult-born hippocampal cells in the prevention of depression and related mood disorders. We first showed that zinc supplementation prevents the development of the depression-like behavior anhedonia associated with an animal model of traumatic brain injury (TBI). This work then examined the effect of zinc supplementation on the proliferation of new cells in the hippocampus that have the potential to participate in neurogenesis. Rats were fed a zinc adequate (ZA, 30ppm) or zinc supplemented (ZS, 180ppm) diet for 4wk followed by TBI using controlled cortical impact. Stereological counts of EdU-positive cells showed that TBI doubled the density of proliferating cells 24h post-injury (pprecursor cells in the hippocampus was robust, use of targeted irradiation to eliminate these cells after zinc supplementation and TBI revealed that these cells are not the sole mechanism through which zinc acts to prevent depression associated with brain injury, and suggest that other zinc dependent mechanisms are needed for the anti-depressant effect of zinc in this model of TBI. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Hippocampus minor and man's place in nature: a case study in the social construction of neuroanatomy.

    Science.gov (United States)

    Gross, C G

    1993-10-01

    In mid-19th century Britain the possibility of evolution and particularly the evolution of man from apes was vigorously contested. Among the leading antievolutionists was the celebrated anatomist and paleontologist Richard Owen and among the leading defenders of evolution was Thomas Henry Huxley. The central dispute between them on human evolution was whether or not man's brain was fundamentally unique in having a hippocampus minor (known today as the calcar avis), a posterior horn in the lateral ventricle, and a posterior lobe. The author considers the background of this controversy, the origin and fate of the term hippocampus minor, why this structure became central to the question of human evolution, and how Huxley used it to support both Darwinism and the political ascendancy of Darwinians. The use of ventricular structures to distinguish humans from other animals appears to reflect an importance given to the ventricles that stretches back to ancient Greek medicine. This account illustrates both the extraordinary persistence of ideas in biology and the role of the political and social matrix in the study of the brain.

  2. An interplay of fusiform gyrus and hippocampus enables prototype- and exemplar-based category learning.

    Science.gov (United States)

    Lech, Robert K; Güntürkün, Onur; Suchan, Boris

    2016-09-15

    The aim of the present study was to examine the contributions of different brain structures to prototype- and exemplar-based category learning using functional magnetic resonance imaging (fMRI). Twenty-eight subjects performed a categorization task in which they had to assign prototypes and exceptions to two different families. This test procedure usually produces different learning curves for prototype and exception stimuli. Our behavioral data replicated these previous findings by showing an initially superior performance for prototypes and typical stimuli and a switch from a prototype-based to an exemplar-based categorization for exceptions in the later learning phases. Since performance varied, we divided participants into learners and non-learners. Analysis of the functional imaging data revealed that the interaction of group (learners vs. non-learners) and block (Block 5 vs. Block 1) yielded an activation of the left fusiform gyrus for the processing of prototypes, and an activation of the right hippocampus for exceptions after learning the categories. Thus, successful prototype- and exemplar-based category learning is associated with activations of complementary neural substrates that constitute object-based processes of the ventral visual stream and their interaction with unique-cue representations, possibly based on sparse coding within the hippocampus. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Synaptically released zinc triggers metabotropic signaling via a zinc-sensing receptor in the hippocampus.

    Science.gov (United States)

    Besser, Limor; Chorin, Ehud; Sekler, Israel; Silverman, William F; Atkin, Stan; Russell, James T; Hershfinkel, Michal

    2009-03-04

    Zn(2+) is coreleased with glutamate from mossy fiber terminals and can influence synaptic function. Here, we demonstrate that synaptically released Zn(2+) activates a selective postsynaptic Zn(2+)-sensing receptor (ZnR) in the CA3 region of the hippocampus. ZnR activation induced intracellular release of Ca(2+), as well as phosphorylation of extracellular-regulated kinase and Ca(2+)/calmodulin kinase II. Blockade of synaptic transmission by tetrodotoxin or CdCl inhibited the ZnR-mediated Ca(2+) rises. The responses mediated by ZnR were largely attenuated by the extracellular Zn(2+) chelator, CaEDTA, and in slices from mice lacking vesicular Zn(2+), suggesting that synaptically released Zn(2+) triggers the metabotropic activity. Knockdown of the expression of the orphan G-protein-coupled receptor 39 (GPR39) attenuated ZnR activity in a neuronal cell line. Importantly, we observed widespread GPR39 labeling in CA3 neurons, suggesting a role for this receptor in mediating ZnR signaling in the hippocampus. Our results describe a unique role for synaptic Zn(2+) acting as the physiological ligand of a metabotropic receptor and provide a novel pathway by which synaptic Zn(2+) can regulate neuronal function.

  4. When Music and Long-Term Memory Interact: Effects of Musical Expertise on Functional and Structural Plasticity in the Hippocampus

    Science.gov (United States)

    Groussard, Mathilde; La Joie, Renaud; Rauchs, Géraldine; Landeau, Brigitte; Chételat, Gaël; Viader, Fausto; Desgranges, Béatrice; Eustache, Francis; Platel, Hervé

    2010-01-01

    The development of musical skills by musicians results in specific structural and functional modifications in the brain. Surprisingly, no functional magnetic resonance imaging (fMRI) study has investigated the impact of musical training on brain function during long-term memory retrieval, a faculty particularly important in music. Thus, using fMRI, we examined for the first time this process during a musical familiarity task (i.e., semantic memory for music). Musical expertise induced supplementary activations in the hippocampus, medial frontal gyrus, and superior temporal areas on both sides, suggesting a constant interaction between episodic and semantic memory during this task in musicians. In addition, a voxel-based morphometry (VBM) investigation was performed within these areas and revealed that gray matter density of the hippocampus was higher in musicians than in nonmusicians. Our data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity in the hippocampus. PMID:20957158

  5. When music and long-term memory interact: effects of musical expertise on functional and structural plasticity in the hippocampus.

    Directory of Open Access Journals (Sweden)

    Mathilde Groussard

    Full Text Available The development of musical skills by musicians results in specific structural and functional modifications in the brain. Surprisingly, no functional magnetic resonance imaging (fMRI study has investigated the impact of musical training on brain function during long-term memory retrieval, a faculty particularly important in music. Thus, using fMRI, we examined for the first time this process during a musical familiarity task (i.e., semantic memory for music. Musical expertise induced supplementary activations in the hippocampus, medial frontal gyrus, and superior temporal areas on both sides, suggesting a constant interaction between episodic and semantic memory during this task in musicians. In addition, a voxel-based morphometry (VBM investigation was performed within these areas and revealed that gray matter density of the hippocampus was higher in musicians than in nonmusicians. Our data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity in the hippocampus.

  6. Inactivation of the dorsal hippocampus or the medial prefrontal cortex impairs retrieval but has differential effect on spatial memory reconsolidation.

    Science.gov (United States)

    Rossato, Janine I; Köhler, Cristiano A; Radiske, Andressa; Bevilaqua, Lia R M; Cammarota, Martín

    2015-11-01

    Active memories can incorporate new information through reconsolidation. However, the notion that memory retrieval is necessary for reconsolidation has been recently challenged. Non-reinforced retrieval induces hippocampus and medial prefrontal cortex (mPFC)-dependent reconsolidation of spatial memory in the Morris water maze (MWM). We found that the effect of protein synthesis inhibition on this process is abolished when retrieval of the learned spatial preference is hindered through mPFC inactivation but not when it is blocked by deactivation of dorsal CA1. Our results do not fully agree with the hypothesis that retrieval is unneeded for reconsolidation. Instead, they support the idea that a hierarchic interaction between the hippocampus and the mPFC controls spatial memory in the MWM, and indicate that this cortex is sufficient to retrieve the information essential to reconsolidate the spatial memory trace, even when the hippocampus is inactivated. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. The hippocampus as a "stupid," domain-specific module: Implications for theories of recent and remote memory, and of imagination.

    Science.gov (United States)

    Moscovitch, Morris

    2008-03-01

    The hippocampus and surrounding regions of the medial temporal lobe play a central role in all neuropsychological theories of memory. It is still a matter of debate, however, how best to characterise the functions of these regions, the hippocampus in particular. In this article, I examine the proposal that the hippocampus is a "stupid" module whose specific domain is consciously apprehended information. A number of interesting consequences for the organisation of memory and the brain follow from this proposal and the assumptions it entails. These, in turn, have important implications for neuropsychological theories of recent and remote episodic, semantic, and spatial memory and for the functions that episodic memory may serve in perception, comprehension, planning, imagination, and problem solving. I consider these implications by selectively reviewing the literature and primarily drawing on research my collaborators and I have conducted. Copyright (c) 2008 APA, all rights reserved.

  8. Anxiolytic-like effects after vector-mediated overexpression of neuropeptide Y in the amygdala and hippocampus of mice

    DEFF Research Database (Denmark)

    Christiansen, Søren Hofman Oliveira; Olesen, Mikkel Vestergaard; Gøtzsche, Casper René

    2014-01-01

    , injections of rAAV-NPY caused significant anxiolytic-like effect in the open field, elevated plus maze, and light-dark transition tests. In the hippocampus, rAAV-NPY treatment was associated with anxiolytic-like effect only in the elevated plus maze. No additive effect was observed after combined r....... Using a recombinant adeno-associated viral (rAAV) vector, we addressed this idea by testing effects on anxiolytic- and depression-like behaviours in adult mice after overexpression of NPY transgene in the amygdala and/or hippocampus, two brain regions implicated in emotional behaviours. In the amygdala......AAV-NPY injection into both the amygdala and hippocampus where anxiolytic-like effect was found in the elevated plus maze and light-dark transition tests. Antidepressant-like effects were not detected in any of the rAAV-NPY injected groups. Immobility was even increased in the tail suspension and forced swim tests...

  9. When music and long-term memory interact: effects of musical expertise on functional and structural plasticity in the hippocampus.

    Science.gov (United States)

    Groussard, Mathilde; La Joie, Renaud; Rauchs, Géraldine; Landeau, Brigitte; Chételat, Gaël; Viader, Fausto; Desgranges, Béatrice; Eustache, Francis; Platel, Hervé

    2010-10-05

    The development of musical skills by musicians results in specific structural and functional modifications in the brain. Surprisingly, no functional magnetic resonance imaging (fMRI) study has investigated the impact of musical training on brain function during long-term memory retrieval, a faculty particularly important in music. Thus, using fMRI, we examined for the first time this process during a musical familiarity task (i.e., semantic memory for music). Musical expertise induced supplementary activations in the hippocampus, medial frontal gyrus, and superior temporal areas on both sides, suggesting a constant interaction between episodic and semantic memory during this task in musicians. In addition, a voxel-based morphometry (VBM) investigation was performed within these areas and revealed that gray matter density of the hippocampus was higher in musicians than in nonmusicians. Our data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity in the hippocampus.

  10. Early-life stress impacts the developing hippocampus and primes seizure occurrence: cellular, molecular, and epigenetic mechanisms

    Science.gov (United States)

    Huang, Li-Tung

    2014-01-01

    Early-life stress includes prenatal, postnatal, and adolescence stress. Early-life stress can affect the development of the hypothalamic-pituitary-adrenal (HPA) axis, and cause cellular and molecular changes in the developing hippocampus that can result in neurobehavioral changes later in life. Epidemiological data implicate stress as a cause of seizures in both children and adults. Emerging evidence indicates that both prenatal and postnatal stress can prime the developing brain for seizures and an increase in epileptogenesis. This article reviews the cellular and molecular changes encountered during prenatal and postnatal stress, and assesses the possible link between these changes and increases in seizure occurrence and epileptogenesis in the developing hippocampus. In addititon, the priming effect of prenatal and postnatal stress for seizures and epileptogenesis is discussed. Finally, the roles of epigenetic modifications in hippocampus and HPA axis programming, early-life stress, and epilepsy are discussed. PMID:24574961

  11. Anisomycin administered in the olfactory bulb and dorsal hippocampus impaired social recognition memory consolidation in different time-points.

    Science.gov (United States)

    Pena, R R; Pereira-Caixeta, A R; Moraes, M F D; Pereira, G S

    2014-10-01

    To identify an individual as familiar, rodents form a specific type of memory named social recognition memory. The olfactory bulb (OB) is an important structure for social recognition memory, while the hippocampus recruitment is still controversial. The present study was designed to elucidate the OB and the dorsal hippocampus contribution to the consolidation of social memory. For that purpose, we tested the effect of anisomycin (ANI), which one of the effects is the inhibition of protein synthesis, on the consolidation of social recognition memory. Swiss adult mice with cannulae implanted into the CA1 region of the dorsal hippocampus or into the OB were exposed to a juvenile during 5 min (training session; TR), and once again 1.5 h or 24 h later to test social short-term memory (S-STM) or social long-term memory (S-LTM), respectively. To study S-LTM consolidation, mice received intra-OB or intra-CA1 infusion of saline or ANI immediately, 3, 6 or 18 h after TR. ANI impaired S-LTM consolidation in the OB, when administered immediately or 6h after TR. In the dorsal hippocampus, ANI was amnesic only if administered 3 h after TR. Furthermore, the infusion of ANI in either OB or CA1, immediately after training, did not affect S-STM. Moreover, ANI administered into the OB did not alter the animal's performance in the buried food-finding task. Altogether, our results suggest the consolidation of S-LTM requires both OB and hippocampus participation, although in different time points. This study may help shedding light on the specific roles of the OB and dorsal hippocampus in social recognition memory. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. MRI Volumetry of Hippocampus and Amygdala in Normal Aging, Mild Cognitive Impairment and Alzheimer's Disease Subjects

    International Nuclear Information System (INIS)

    Suphaphong, S.; Tritanon, O.; Laothamatas, J.; Sungkarat, W.

    2012-01-01

    The Alzheimer's disease (AD) and mild cognitive impairment (MCI) can affect memory and daily living. Non- invasive diagnostic tools such as MRI can be useful to discriminate the patients from normal group.This study aims to compare the relative volumes of hippocampus and amygdala, to suggest the relative normal volumes, and to evaluate MRI automatic volumetry as a diagnostic tool. The MRI images of 130 subjects were retrospectively studied (Turbo field echo (TFE), acquired with a 3-Tesla Philips scanner). The image data were processed with Free Surfer (automatic segmentation and volumetry). The resultant volumes were corrected for brain size differences with intracranial volumes (ICV), and then analysed with SPSS (v. 17.0). There are differences of hippocampus and amygdala relative volumes between normal, MCI, and AD subjects at p < 0.001. The volume reductions of hippocampus in MCI and AD groups compared to normal group are about 8 % and 28 %, while those of amygdala are about 10 % and 34 %, respectively. The relative volumes of hippocampus (compared to ICV) in normal aging are 0.002617 ± 0.000278 (right) and 0.002553 ± 0.000257 (left), while those of amygdala are 0.001231 ± 0.000165 (right) and 0.001096 ± 0.000144 (left). There are no differences of relative volumes affected by gender in normal, MCI, and AD. There is a highly significant difference of relative volume affected by brain side in normal group (p < 0.001) but not in MCI (p = 0.119 and 0.077) and AD (p = 0.713 and 0.250), for hippocampus and amygdala, respectively. These results demonstrate that there are volume losses of hippocampus and amygdala in both diseases. Automatically measured hippocampus and amygdala volumes can be used as a measure indicating MCI and AD. The abnormal disturbance of volume affected by brain side may indicate the progression of both diseases. The hippocampus and amygdala volumes can be used as one of diagnostic tools to confirm the diagnosis of MCI or AD. The volume

  13. New records of the Japanese seahorse Hippocampus mohnikei in Southeast Asia lead to updates in range, habitat and threats.

    Science.gov (United States)

    Aylesworth, L; Lawson, J M; Laksanawimol, P; Ferber, P; Loh, T-L

    2016-04-01

    New records of the Japanese seahorse Hippocampus mohnikei from Cambodia, Malaysia, Thailand and Vietnam, along with recently published studies from India and Singapore, have greatly expanded the known range of H. mohnikei within Southeast Asia. These new records reveal novel habitat preferences and threats to H. mohnikei in the region. Although the global conservation status of H. mohnikei is classified as Data Deficient according to the IUCN Red List of Threatened Species, new sightings indicate that this species is found in similar habitats and faces similar threats as other Hippocampus species that are considered Vulnerable. © 2016 The Fisheries Society of the British Isles.

  14. The impact of maternal separation on adult mouse behaviour and on the total neuron number in the mouse hippocampus

    DEFF Research Database (Denmark)

    Fabricius, K.; Wörtwein, Gitta; Pakkenberg, B.

    2008-01-01

    , the number of errors made by the MS24 mice compared to controls and in total distance moved. The mice were subsequently sacrificed and the total number of neurons estimated in the hippocampus using the optical fractionator. We found a significant loss of neurons in the dentate gyrus in MS mice compared...... to controls. Apparently a single maternal separation can impact the number of neurons in mouse hippocampus either by a decrease of neurogenesis or as an increase in neuron apoptosis. This study is the first to assess the result of maternal separation combining behaviour and stereology Udgivelsesdato: 2008/2...

  15. Visualization of Functional Neuropeptide Y Receptors in the Mouse Hippocampus and Neocortex Using [35S]GTPγS Binding

    DEFF Research Database (Denmark)

    Elbrønd-Bek, Heidi; Gøtzsche, Casper René; Skinbjerg, Mette

    2015-01-01

    The peptide transmitter neuropeptide Y (NPY) has been implicated in a plethora of actions in the central nervous system, including the hippocampus and neocortex (NeoCx). Previous studies using traditional receptor autoradiography show that NPY receptor binding is altered under various pathophysio......The peptide transmitter neuropeptide Y (NPY) has been implicated in a plethora of actions in the central nervous system, including the hippocampus and neocortex (NeoCx). Previous studies using traditional receptor autoradiography show that NPY receptor binding is altered under various...

  16. Glucose Injections into the Dorsal Hippocampus or Dorsolateral Striatum of Rats Prior to T-Maze Training: Modulation of Learning Rates and Strategy Selection

    Science.gov (United States)

    Canal, Clinton E.; Stutz, Sonja J.; Gold, Paul E.

    2005-01-01

    The present experiments examined the effects of injecting glucose into the dorsal hippocampus or dorsolateral striatum on learning rates and on strategy selection in rats trained on a T-maze that can be solved by using either a hippocampus-sensitive place or striatum-sensitive response strategy. Percentage strategy selection on a probe trial…

  17. Long-lasting enhancement of synaptic excitability of CA1/subiculum neurons of the rat ventral hippocampus by vasopressin and vasopressin(4-8)

    NARCIS (Netherlands)

    Gispen, W.H.; Chepkova, A.N.; French, P.; Wied, D. de; Ontskul, A.H.; Ramakers, G.M.J.; Skrebitski, V.G.; Urban, I.J.A.

    1995-01-01

    Vasopressin (VP) is axonally distributed in many brain structures, including the ventral hippocampus. Picogram quantities of VP injected into the hippocampus improve the passive avoidance response of rats, presumably by enhancing memory processes. Vasopressin is metabolized by the brain tissue into

  18. Atlas selection for hippocampus segmentation: Relevance evaluation of three meta-information parameters.

    Science.gov (United States)

    Dill, Vanderson; Klein, Pedro Costa; Franco, Alexandre Rosa; Pinho, Márcio Sarroglia

    2018-04-01

    Current state-of-the-art methods for whole and subfield hippocampus segmentation use pre-segmented templates, also known as atlases, in the pre-processing stages. Typically, the input image is registered to the template, which provides prior information for the segmentation process. Using a single standard atlas increases the difficulty in dealing with individuals who have a brain anatomy that is morphologically different from the atlas, especially in older brains. To increase the segmentation precision in these cases, without any manual intervention, multiple atlases can be used. However, registration to many templates leads to a high computational cost. Researchers have proposed to use an atlas pre-selection technique based on meta-information followed by the selection of an atlas based on image similarity. Unfortunately, this method also presents a high computational cost due to the image-similarity process. Thus, it is desirable to pre-select a smaller number of atlases as long as this does not impact on the segmentation quality. To pick out an atlas that provides the best registration, we evaluate the use of three meta-information parameters (medical condition, age range, and gender) to choose the atlas. In this work, 24 atlases were defined and each is based on the combination of the three meta-information parameters. These atlases were used to segment 352 vol from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Hippocampus segmentation with each of these atlases was evaluated and compared to reference segmentations of the hippocampus, which are available from ADNI. The use of atlas selection by meta-information led to a significant gain in the Dice similarity coefficient, which reached 0.68 ± 0.11, compared to 0.62 ± 0.12 when using only the standard MNI152 atlas. Statistical analysis showed that the three meta-information parameters provided a significant improvement in the segmentation accuracy. Copyright © 2018 Elsevier Ltd

  19. Chronic hydrocephalus-induced hypoxia: increased expression of VEGFR-2+ and blood vessel density in hippocampus.

    Science.gov (United States)

    Dombrowski, S M; Deshpande, A; Dingwall, C; Leichliter, A; Leibson, Z; Luciano, M G

    2008-03-18

    Chronic hydrocephalus (CH) is a neurological disease characterized by increased cerebrospinal fluid volume and pressure that is often associated with impaired cognitive function. By and large, CH is a complex and heterogeneous cerebrospinal fluid (CSF) disorder where the exact site of brain insult is uncertain. Several mechanisms including neural compression, fiber stretch, and local or global hypoxia have been implicated in the underlying pathophysiology of CH. Specifically, the hippocampus, which plays a significant role in memory processing and is in direct contact with expanding CSF ventricles, may be involved. Using our model of chronic hydrocephalus, we quantified the density of vascular endothelial growth factor receptor 2 (VEGFR-2(+)) neurons, glial, endothelial cells, and blood vessels in hippocampal regions CA1, CA2-3, dentate gyrus and hilus using immunohistochemical and stereological methods. Density and %VEGFR-2(+) cell populations were estimated for CH animals (2-3 weeks vs. 12-16 weeks) and surgical controls (SC). Overall, we found approximately six- to eightfold increase in the cellular density of VEGFR-2(+) and more than double blood vessel density (BVd) in the hippocampus of CH compared with SC. There were no significant regional differences in VEGFR-2(+) cellular and BVd expression in the CH group. VEGFR-2(+) and BVds were significantly related to changes in CSF volume (Phippocampus that corresponded to increased BVd. It was unclear whether increased VEGFR-2(+) and blood vessel expression was related to focal compression alone or in combination with global ischemia/hypoxia conditions as previously described. These findings suggest that VEGFR-2 may play an adaptive role in angiogenesis after CH

  20. Amygdala modulation of memory-related processes in the hippocampus: potential relevance to PTSD.

    Science.gov (United States)

    Tsoory, M M; Vouimba, R M; Akirav, I; Kavushansky, A; Avital, A; Richter-Levin, G

    2008-01-01

    A key assumption in the study of stress-induced cognitive and neurobiological modifications is that alterations in hippocampal functioning after stress are due to an excessive activity exerted by the amygdala on the hippocampus. Research so far focused on stress-induced impairment of hippocampal plasticity and memory but an exposure to stress may simultaneously also result in strong emotional memories. In fact, under normal conditions emotionally charged events are better remembered compared with neutral ones. Results indicate that under these conditions there is an increase in activity within the amygdala that may lead to memory of a different quality. Studying the way emotionality activates the amygdala and the functional impact of this activation we found that the amygdala modulates memory-related processes in other brain areas, such as the hippocampus. However, this modulation is complex, involving both enhancing and suppressing effects, depending on the way the amygdala is activated and the hippocampal subregion examined. The current review summarizes our findings and attempts to put them in context with the impact of an exposure to a traumatic experience, in which there is a mixture of a strong memory of some aspects of the experience but impaired memory of other aspects of that experience. Toward that end, we have recently developed an animal model for the induction of predisposition to stress-related disorders, focusing on the consequences of exposure to stressors during juvenility on the ability to cope with stress in adulthood. Exposing juvenile-stressed rats to an additional stressful challenge in adulthood revealed their impairment to cope with stress and resulted in significant elevation of the amygdala. Interestingly, and similar to our electrophysiological findings, differential effects were observed between the impact of the emotional challenge on CA1 and dentate gyrus subregions of the hippocampus. Taken together, the results indicate that long

  1. Field studies of a Brazilian seahorse population, Hippocampus reidi Ginsburg, 1933

    Directory of Open Access Journals (Sweden)

    Natalie Villar Freret-Meurer

    2008-08-01

    Full Text Available This study was carried out to fill the gaps that remain under Hippocampus reidi biology. Analysis of variations of sex ratio, density, breeding season, distribution and home range of a population of the endangered Brazilian seahorse H. reidi from a rocky shore on Araçatiba beach, Ilha Grande, Brazil were carried out. Araçatiba beach is a tourist Environmental Protected Area, suffering antropic pressure. A fixed population of H. reidi was studied, where al lthe individuals were visually tagged and sex, reproductive state and location on site were identified from December 2002 to November 2004. A total of 20 individuals were visually tagged with a mean density of 0.18 m-2. Sex ratios were skewed, with more females than males. All the males brooded during 13 months and presented smaller home range than the females during the breeding season. The highest densities were found on shallowest areas.Este estudo foi realizado com o objetivo de preencher algumas lacunas sobre a biologia natural de Hippocampus reidi. Foram analisadas as variações na proporção sexual e densidade, período reprodutivo, distribuição e área de deslocamento de uma população do cavalo marinho brasileiro ameaçado de extinção Hippocampus reidi de um costão rochoso da praia de Araçatiba, Ilha Grande, Brasil. A praia de Araçatiba é uma Área de Proteção Ambiental turística, a qual sofre com a pressão antropogênica. Foi estudada uma população fixa de H. reidi, sendo que todos os indivíduos foram marcados visualmente e foram determinados o sexo, o período reprodutivo e a localização na área de novembro de 2002 a novembro de 2004. Um total de 20 indivíduos foram marcados com uma densidade média na área de 0,18 m-2. A proporção sexual variou de forma alternada com maior número de fêmeas que de machos. Durante 13 meses todos os machos encontrados estavam incubando. Os cavalos marinhos apresentaram área de deslocamento menor que as fêmeas durante o

  2. Desenvolvimento osteológico de Hippocampus reidi Ginsburg (Pisces, Syngnathiformes, Syngnathidae, em laboratório: II. Período juvenil Osteologic development of Hippocampus reidi Ginsburg (Pisces, Syngnathiformes, Syngnathidae, under laboratory conditions: II. Juvenile phase

    Directory of Open Access Journals (Sweden)

    Rosana Beatriz Silveira

    2000-06-01

    Full Text Available The sequence of events of the ossification process in the newly bom specimens of Hippocampus reidi Ginsburg, 1933 up to 37 days of life has been described, mainly the ossification in the ethmoid plate, palatine, pectoral girdle, and postorbital bones and bony structures such as mesoethmoid, articular and six suborbitals. Observation on adult specimens are presented too.

  3. States of curiosity modulate hippocampus-dependent learning via the dopaminergic circuit.

    Science.gov (United States)

    Gruber, Matthias J; Gelman, Bernard D; Ranganath, Charan

    2014-10-22

    People find it easier to learn about topics that interest them, but little is known about the mechanisms by which intrinsic motivational states affect learning. We used functional magnetic resonance imaging to investigate how curiosity (intrinsic motivation to learn) influences memory. In both immediate and one-day-delayed memory tests, participants showed improved memory for information that they were curious about and for incidental material learned during states of high curiosity. Functional magnetic resonance imaging results revealed that activity in the midbrain and the nucleus accumbens was enhanced during states of high curiosity. Importantly, individual variability in curiosity-driven memory benefits for incidental material was supported by anticipatory activity in the midbrain and hippocampus and by functional connectivity between these regions. These findings suggest a link between the mechanisms supporting extrinsic reward motivation and intrinsic curiosity and highlight the importance of stimulating curiosity to create more effective learning experiences. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. States of curiosity modulate hippocampus-dependent learning via the dopaminergic circuit

    Science.gov (United States)

    Gruber, Matthias J.; Gelman, Bernard D.; Ranganath, Charan

    2014-01-01

    Summary People find it easier to learn about topics that interest them, but little is known about the mechanisms by which intrinsic motivational states affect learning. We used functional magnetic resonance imaging to investigate how curiosity (intrinsic motivation to learn) influences memory. In both immediate and one-day delayed memory tests, participants showed improved memory for information that they were curious about, and also for incidental material learned during states of high curiosity. FMRI results revealed that activity in the midbrain and the nucleus accumbens was enhanced during states of high curiosity. Importantly, individual variability in curiosity-driven memory benefits for incidental material was supported by anticipatory activity in the midbrain and hippocampus and by functional connectivity between these regions. These findings suggest a link between the mechanisms supporting extrinsic reward motivation and intrinsic curiosity and highlight the importance of stimulating curiosity in order to create more effective learning experiences. PMID:25284006

  5. Ethanol affects network activity in cultured rat hippocampus: mediation by potassium channels.

    Directory of Open Access Journals (Sweden)

    Eduard Korkotian

    Full Text Available The effects of ethanol on neuronal network activity were studied in dissociated cultures of rat hippocampus. Exposure to low (0.25-0.5% ethanol concentrations caused an increase in synchronized network spikes, and a decrease in the duration of individual spikes. Ethanol also caused an increase in rate of miniature spontaneous excitatory postsynaptic currents. Higher concentrations of ethanol eliminated network spikes. These effects were reversible upon wash. The effects of the high, but not the low ethanol were blocked by the GABA antagonist bicuculline. The enhancing action of low ethanol was blocked by apamin, an SK potassium channel antagonist, and mimicked by 1-EBIO, an SK channel opener. It is proposed that in cultured hippocampal networks low concentration of ethanol is associated with SK channel activity, rather than the GABAergic receptor.

  6. Phencyclidine administration during neurodevelopment alters network activity in prefrontal cortex and hippocampus in adult rats

    DEFF Research Database (Denmark)

    Kjaerby, Celia; Hovelsø, Nanna; Dalby, Nils Ole

    2017-01-01

    Symptoms of schizophrenia have been linked to insults during neurodevelopment such as NMDA receptor (NMDAR) antagonist exposure. In animal models, this leads to schizophrenia-like behavioral symptoms as well as molecular and functional changes within hippocampal and prefrontal regions. The aim of...... in the evolvement of schizophrenia-like symptoms and contribute to the understanding of the functional deficits underlying aberrant behavior in this disease.......Symptoms of schizophrenia have been linked to insults during neurodevelopment such as NMDA receptor (NMDAR) antagonist exposure. In animal models, this leads to schizophrenia-like behavioral symptoms as well as molecular and functional changes within hippocampal and prefrontal regions. The aim...... that NMDAR antagonist exposure during brain development alters functional networks within hippocampus and mPFC possibly contributing to the reported behavioral symptoms of this animal model of schizophrenia.NEW & NOTEWORTHY We show that insults with a NMDA receptor antagonist during neurodevelopment lead...

  7. Population characteristics, space use and habitat associations of the seahorse Hippocampus reidi (Teleostei: Syngnathidae

    Directory of Open Access Journals (Sweden)

    Ierecê Lucena Rosa

    Full Text Available This paper provides a case study of a threatened seahorse species, Hippocampus reidi, highlighting the importance of using ecological information to assist conservation and management initiatives. Underwater visual sighting data (50 x 2m transect gathered along the NE, SE and S portions of the Brazilian coast revealed an unequal distribution across localities, perhaps related to harvesting pressure, and a mean density of 0.026 ind.m-2. Our findings suggest some restricted spatial use by H. reidi, which was consistent with its estimated home range, and with re-sighting of specimens. Reproduction was recorded year-round, however productive peaks may exist. Components of habitat structure mostly used as anchoring points were mangrove plants, macroalgae, cnidarians, seagrass, sponges, and bryozoans. Conservation recommendations include: further characterization and mapping of habitats; assessment of availability and condition of microhabitats in selected areas, and studies on dispersal routes during initial life stages.

  8. A novel nicotinic agonist facilitates induction of long-term potentiation in the rat hippocampus.

    Science.gov (United States)

    Hunter, B E; de Fiebre, C M; Papke, R L; Kem, W R; Meyer, E M

    1994-02-28

    Long-term potentiation (LTP) can be modulated by a number of neurotransmitter receptors including muscarinic and GABAergic receptor types. We have found that a novel nicotinic agonist, 2,4-dimethoxybenzylidene anabaseine (DMXB), facilitated the induction of LTP in the hippocampus in a dose-dependent and mecamylamine-sensitive manner. DMXB displaced high affinity nicotinic [125I]alpha-bungarotoxin and [3H]acetylcholine binding in rat brain. Xenopus oocyte studies demonstrated that DMXB has agonist activity at alpha 7 but not alpha 4/beta 2 nicotinic receptor subtypes. These results indicated that DMXB is a novel nicotinic agonist with apparent specificity for the alpha 7/alpha-bungarotoxin nicotinic receptor subtype and indicate that nicotinic receptor activation is capable of modulating the induction of long-term potentiation.

  9. NeuN Expression Alterations in the Hippocampus Following Ecstasy Treatment

    Directory of Open Access Journals (Sweden)

    Ghasemi Moravej

    2016-05-01

    Full Text Available Background The administration of 3-4-methylenedioxymethamphetamine (MDMA leads to learning and memory impairment. Objectives Due to the effect of neurogenesis on memory and learning, in this study, we investigated the effects of MDMA on NeuN expression (a marker of neurogenesis in the hippocampus. Methods Adult male Wistar rats (weighing 200 - 250 g received a single intraperitoneal dose of 10 mg/kg of MDMA or were left undisrupted. The expression of NeuN was assessed using the immunohistochemistry method 7, 14, 28, and 60 days following MDMA administration. Results Our results showed that MDMA administration caused a decrease in NeuN expression in the experimental group compared with the control group. Conclusions These results suggest a negative correlation between MDMA administration and adult hippocampal neurogenesis.

  10. Epilepsy Surgery for Skull-Base Temporal Lobe Encephaloceles: Should We Spare the Hippocampus from Resection?

    Science.gov (United States)

    Bannout, Firas; Harder, Sheri; Lee, Michael; Zouros, Alexander; Raghavan, Ravi; Fogel, Travis; De Los Reyes, Kenneth; Losey, Travis

    2018-01-01

    The neurosurgical treatment of skull base temporal encephalocele for patients with epilepsy is variable. We describe two adult cases of temporal lobe epilepsy (TLE) with spheno-temporal encephalocele, currently seizure-free for more than two years after anterior temporal lobectomy (ATL) and lesionectomy sparing the hippocampus without long-term intracranial electroencephalogram (EEG) monitoring. Encephaloceles were detected by magnetic resonance imaging (MRI) and confirmed by maxillofacial head computed tomography (CT) scans. Seizures were captured by scalp video-EEG recording. One case underwent intraoperative electrocorticography (ECoG) with pathology demonstrating neuronal heterotopia. We propose that in some patients with skull base temporal encephaloceles, minimal surgical resection of herniated and adjacent temporal cortex (lesionectomy) is sufficient to render seizure freedom. In future cases, where an associated malformation of cortical development is suspected, newer techniques such as minimally invasive EEG monitoring with stereotactic-depth EEG electrodes should be considered to tailor the surrounding margins of the resected epileptogenic zone. PMID:29534521

  11. Complete mitochondrial genome sequence of the hedgehog seahorse Hippocampus spinosissimus Weber, 1933 (Gasterosteiformes:Syngnathidae).

    Science.gov (United States)

    Liu, Shuaishuai; Zhang, Yanhong; Wang, Changming; Lin, Qiang

    2016-07-01

    The complete mitochondrial genome sequence of the hedgehog seahorse Hippocampus spinosissimus was first determined in this article. The total length of H. spinosissimus mitogenome is 16 527 bp and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 control region. The gene order and composition of H. spinosissimus were similar to those of most other vertebrates. The overall base composition of H. spinosissimus is 32.1% A, 30.3% T, 14.9% G and 22.7% C, with a slight A + T-rich feature (62.4%). Phylogenetic analyses based on complete mitochondrial genome sequence showed that H. spinosissimus has a close genetic relationship to H. ingens and H. kuda.

  12. First feeding regimes for long-snout seahorse Hippocampus reidi larvae.

    Science.gov (United States)

    Garcia-Manchón, J; Socorro-Cruz, J; Segade Botella, A; Otero-Ferrer, F; Mesa, A; Molina Domínguez, L

    2013-01-01

    Seahorses are endangered species included in Appendix II of CITES from 2002 due to the progressive regression of wild populations. This study focused in Hippocampus reidi, one of the species with highest interest in trade, showing an increasing demand in the last decades. This study was conducted during 28 days to compare the effects of different time enrichment (0, 24, and 48h) for Artemia using a commercial product (Easy-Selco DHA INVE Aquaculture, Dendermonde, Belgium). Results showed no significant differences in growth between treatments until 21DAB, after which animals fed for 48h one enriched Artemia showed significantly better growth. Cumulative average survival during the first 14DAB was significantly higher in Oh treatment, while from 15DAB to the end of the experiment, no significantly differences were observed.

  13. Effects of neonatal. gamma. -ray irradiation on rat hippocampus: Pt. 1; Postnatal maturation of hippocampal cells

    Energy Technology Data Exchange (ETDEWEB)

    Represa, A; Dessi, F; Beaudoin, M; Ben-Ari, Y [Institut National de la Sante et de la Recherche Medicale (INSERM), 75 - Paris (France)

    1991-01-01

    The axons of dentate granule cells, the mossy fibres, establish synaptic contacts with the thorny excrescences of the apical dendrite of CA3 pyramidal neurons. Dentate granule cells develop postnatally in rats, whereas the CA3 pyramidal cells are generated before birth. In the present studies, using unilateral neonatal {gamma}-ray irradiation to destroy the granule cells in one hemisphere, we have studied the effect of mossy fibre deprivation on the development of their targets. We show that such ''degranulation'' prevents the normal development of giant thorny excrescences, suggesting that the development of thorny excrescences in CA3 pyramidal neurons is under the control of mossy fibres. In contrast, irradiation of the hippocampus of the neonatal rat does not affect the development of the dendritic arborization of CA3 pyramidal cells and their non-mossy dendritic spines. (author).

  14. Neuron activity in rat hippocampus and motor cortex during discrimination reversal.

    Science.gov (United States)

    Disterhoft, J F; Segal, M

    1978-01-01

    Chronic unit activity and gross movement were recorded from rats during two discrimination reversals in a classical appetitive conditioning situation. The anticipatory movement decreased in response to the former CS+ tone and increased to the previous CS- tone after each reversal. Hippocampus and motor cortex were differently related to these two kinds of behavioral change. Response rates of hippocampal neurons were more closely related to the increased movement response to the former CS- which now signaled food. Motor cortex neuron responses were more closely correlated with the decrease in movement responses to the former CS+ which became neutral after the reversal. It appeared that hippocampal neurons could have been involved in one cognitive aspect of the situation, motor cortex neurons in another. The data were related to current functional concepts of these brain regions.

  15. Estresse, depressão e hipocampo Stress, depression and the hippocampus

    Directory of Open Access Journals (Sweden)

    Sâmia Regiane L Joca

    2003-12-01

    Full Text Available A exposição a fatores estressantes tem papel importante no desenvolvimento de transtornos depressivos. Os mecanismos envolvidos nesta relação, no entanto, ainda são pouco conhecidos, mas algumas evidências sugerem a participação da formação hipocampal: 1. o estresse pode causar alterações plásticas no hipocampo, que incluem remodelação dendrítica e inibição de neurogênese. Drogas antidepressivas impendem estes efeitos, possivelmente por aumentarem a expressão de fatores neurotróficos; 2. a facilitação da neurotransmissão serotoninérgica no hipocampo atenua conseqüências comportamentais do estresse e produz efeitos antidepressivos em modelos animais; 3. o antagonismo do principal neurotransmissor excitatório no hipocampo, o glutamato, produz efeitos semelhantes; 4. o hipocampo parece estar "hiperativo" em animais mais sensíveis em modelos de depressão e em humanos resistentes à antidepressivos; 5. o hipocampo, em conjunto com o complexo amigdalar, parece ter papel fundamental na consolidação e evocação de memórias aversivas. Não obstante estas evidências, o desafio futuro será o de tentar integrar os resultados destes diferentes campos (farmacológico, molecular, eletrofisiológico, clínico em uma teoria unificadora sobre o papel do hipocampo na regulação do humor e seus transtornos bem como nos efeitos de tratamentos antidepressivos.Stress exposure is an important factor in the development of depressive disorders. Although the mechanisms of this relationship are largely unknown, several pieces of evidence point to an involvement of the hippocampal formation: 1. stressful stimuli cause remodeling of hipocampal pyramidal cells and inhibit neurogenesis in the dentate gyrus. Antidepressive drugs attenuate these effects, probably by increasing the expression of neurotrophic factors; 2. facilitation of serotonergic neurotransmission in the hippocampus attenuates behavioral consequences of stress and produce

  16. High-dose dextromethorphan produces myelinoid bodies in the hippocampus of rats

    Directory of Open Access Journals (Sweden)

    Hai-Quyen Tran

    2016-10-01

    Full Text Available Dextromethorphan (DM administered at supra-antitussive doses produce psychotoxic and neurotoxic effects in humans. We administered DM (80 mg/kg to rats intraperitoneally to determine the ultrastructural change induced by DM, because intraperitoneal route is sensitive for the behavioral responses. Treatment with DM resulted in mitochondrial dysfunction and formation of myelinoid bodies in the hippocampus. MK-801 [(+-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] attenuated DM-induced cytosolic oxidative burdens. However, neither MK-801 nor naloxone affected DM-induced mitochondrial dysfunction and formation of myelinoid bodies, indicating that the neurotoxic mechanism needs to be further elucidated. Therefore, the spectrum of toxicological effects associated with DM need to be reassessed.

  17. Gross, histological and ultrastructural morphology of the aglomerular kidney in the lined seahorse Hippocampus erectus.

    Science.gov (United States)

    Fogelson, S B; Yanong, R P E; Kane, A; Teal, C N; Berzins, I K; Smith, S A; Brown, C; Camus, A

    2015-09-01

    Histologic evaluation of the renal system in the lined seahorse Hippocampus erectus reveals a cranial kidney with low to moderate cellularity, composed of a central dorsal aorta, endothelial lined capillary sinusoids, haematopoietic tissue, fine fibrovascular stroma, ganglia and no nephrons. In comparison, the caudal kidney is moderately to highly cellular with numerous highly convoluted epithelial lined tubules separated by interlacing haematopoietic tissue, no glomeruli, fine fibrovascular stroma, numerous capillary sinusoids, corpuscles of Stannius and clusters of endocrine cells adjacent to large calibre vessels. Ultrastructural evaluation of the renal tubules reveals minimal variability of the tubule epithelium throughout the length of the nephron and the majority of tubules are characterized by epithelial cells with few apical microvilli, elaborate basal membrane infolding, rare electron dense granules and abundant supporting collagenous matrix. © 2015 The Fisheries Society of the British Isles.

  18. High-dose dextromethorphan produces myelinoid bodies in the hippocampus of rats.

    Science.gov (United States)

    Tran, Hai-Quyen; Chung, Yoon Hee; Shin, Eun-Joo; Kim, Won Ki; Lee, Jae-Chul; Jeong, Ji Hoon; Wie, Myung Bok; Jang, Choon-Gon; Yamada, Kiyofumi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2016-10-01

    Dextromethorphan (DM) administered at supra-antitussive doses produce psychotoxic and neurotoxic effects in humans. We administered DM (80 mg/kg) to rats intraperitoneally to determine the ultrastructural change induced by DM, because intraperitoneal route is sensitive for the behavioral responses. Treatment with DM resulted in mitochondrial dysfunction and formation of myelinoid bodies in the hippocampus. MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] attenuated DM-induced cytosolic oxidative burdens. However, neither MK-801 nor naloxone affected DM-induced mitochondrial dysfunction and formation of myelinoid bodies, indicating that the neurotoxic mechanism needs to be further elucidated. Therefore, the spectrum of toxicological effects associated with DM need to be reassessed. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  19. Choline uptake in the hippocampus: inhibition of septal-hippocampal cholinergenic neurons by intraventricular barbiturates

    International Nuclear Information System (INIS)

    Richter, J.A.

    1986-01-01

    The author attempts to determine where in the brain pentobarbital acts to cause the inhibition of high-affinity, sodium-dependent choline uptake, and what behavioral consequences result from this particular effect of barbituates. The experiments were done in male Wistar rats which had received an injection of Nivea cream injected directly to the acannula. In the experiments the drug solution injected into the lateral ventricle was also spiked with ( 14 C) - phenobarbital at a final specific activity of 5 dpm/nmole so that a more precise estimate of the spread of drug solution could be made. When a phenobarbital-Fast green Dye mixture was injected bilaterally into the lateral ventricles, the dye was found to have spread through the entire ventricular system when the rat was killed 10-20 min later. Choline uptake in the hippocampus was inhibited and the inhibition was apparently greater of 20 min rather than 10 min were allowed to elapse after the injection

  20. Fast neutron irradiation deteriorates hippocampus-related memory ability in adult mice.

    Science.gov (United States)

    Yang, Miyoung; Kim, Hwanseong; Kim, Juhwan; Kim, Sung-Ho; Kim, Jong-Choon; Bae, Chun-Sik; Kim, Joong-Sun; Shin, Taekyun; Moon, Changjong

    2012-03-01

    Object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice exposed to cranial fast neutron irradiation (0.8 Gy) were examined to evaluate hippocampus-related behavioral dysfunction following acute exposure to relatively low doses of fast neutrons. In addition, hippocampal neurogenesis changes in adult murine brain after cranial irradiation were analyzed using the neurogenesis immunohistochemical markers Ki-67 and doublecortin (DCX). In the object recognition memory test and contextual fear conditioning, mice trained 1 and 7 days after irradiation displayed significant memory deficits compared to the sham-irradiated controls. The number of Ki-67- and DCX-positive cells decreased significantly 24 h post-irradiation. These results indicate that acute exposure of the adult mouse brain to a relatively low dose of fast neutrons interrupts hippocampal functions, including learning and memory, possibly by inhibiting neurogenesis.

  1. NPY gene transfer in the hippocampus attenuates synaptic plasticity and learning

    DEFF Research Database (Denmark)

    Sørensen, Andreas T; Kanter-Schlifke, Irene; Carli, Mirjana

    2008-01-01

    -mediated mechanisms. In addition, transgene NPY seems to be released during high frequency neuronal activity, leading to decreased glutamate release in excitatory synapses. Importantly, memory consolidation appears to be affected by the treatment. We found that long-term potentiation (LTP) in the CA1 area...... processing. Here we show, by electrophysiological recordings in CA1 of the hippocampal formation of rats, that hippocampal NPY gene transfer into the intact brain does not affect basal synaptic transmission, but slightly alters short-term synaptic plasticity, most likely via NPY Y2 receptor....... Future clinical progress, however, requires more detailed evaluation of possible side effects of this treatment. Until now it has been unknown whether rAAV vector-based NPY overexpression in the hippocampus alters normal synaptic transmission and plasticity, which could disturb learning and memory...

  2. Learning-enhanced coupling between ripple oscillations in association cortices and hippocampus.

    Science.gov (United States)

    Khodagholy, Dion; Gelinas, Jennifer N; Buzsáki, György

    2017-10-20

    Consolidation of declarative memories requires hippocampal-neocortical communication. Although experimental evidence supports the role of sharp-wave ripples in transferring hippocampal information to the neocortex, the exact cortical destinations and the physiological mechanisms of such transfer are not known. We used a conducting polymer-based conformable microelectrode array (NeuroGrid) to record local field potentials and neural spiking across the dorsal cortical surface of the rat brain, combined with silicon probe recordings in the hippocampus, to identify candidate physiological patterns. Parietal, midline, and prefrontal, but not primary cortical areas, displayed localized ripple (100 to 150 hertz) oscillations during sleep, concurrent with hippocampal ripples. Coupling between hippocampal and neocortical ripples was strengthened during sleep following learning. These findings suggest that ripple-ripple coupling supports hippocampal-association cortical transfer of memory traces. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  3. Associative recognition and the hippocampus: differential effects of hippocampal lesions on object-place, object-context and object-place-context memory.

    Science.gov (United States)

    Langston, Rosamund F; Wood, Emma R

    2010-10-01

    The hippocampus is thought to be required for the associative recognition of objects together with the spatial or temporal contexts in which they occur. However, recent data showing that rats with fornix lesions perform as well as controls in an object-place task, while being impaired on an object-place-context task (Eacott and Norman (2004) J Neurosci 24:1948-1953), suggest that not all forms of context-dependent associative recognition depend on the integrity of the hippocampus. To examine the role of the hippocampus in context-dependent recognition directly, the present study tested the effects of large, selective, bilateral hippocampus lesions in rats on performance of a series of spontaneous recognition memory tasks: object recognition, object-place recognition, object-context recognition and object-place-context recognition. Consistent with the effects of fornix lesions, animals with hippocampus lesions were impaired only on the object-place-context task. These data confirm that not all forms of context-dependent associative recognition are mediated by the hippocampus. Subsequent experiments suggested that the object-place task does not require an allocentric representation of space, which could account for the lack of impairment following hippocampus lesions. Importantly, as the object-place-context task has similar spatial requirements, the selective deficit in object-place-context recognition suggests that this task requires hippocampus-dependent neural processes distinct from those required for allocentric spatial memory, or for object memory, object-place memory or object-context memory. Two possibilities are that object, place, and context information converge only in the hippocampus, or that recognition of integrated object-place-context information requires a hippocampus-dependent mode of retrieval, such as recollection. © 2009 Wiley-Liss, Inc.

  4. Acute diffusion abnormalities in the hippocampus of children with new-onset seizures: the development of mesial temporal sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Farina, L. [Department of Neuroradiology, Istituto Nazionale Neurologico C. Besta, Milan (Italy); Department of Pediatrics, Division of Neurology, The Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States); Bergqvist, C.; Zimmerman, R.A.; Haselgrove, J.; Hunter, J.V.; Bilaniuk, L.T. [Department of Pediatrics, Division of Neurology, The Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States); Department of Radiology, The Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States)

    2004-04-01

    We studied the role of early diffusion-weighted imaging DWI in the investigation of children with new-onset prolonged seizures which eventually result in unilateral hippocampal sclerosis (HS). We carried out MRI on five children aged 17 months to 7 years including conventional and diffusion-weighted sequences. We calculated apparent diffusion coefficients (ADC) for the affected and the normal opposite hippocampus. Follow-up examinations were performed, including DWI and ADC measurements in four. We studied four children within 3 days of the onset of prolonged psychomotor seizures and showed increased signal on T2-weighted images, and DWI, indicating restricted diffusion, throughout the affected hippocampus. The ADC were reduced by a mean of 14.4% in the head and by 15% in the body of the hippocampus. In one child examined 15 days after the onset of seizures, the ADC were the same on both sides. All five patients showed hippocampal atrophy on follow-up 2-18 months later. In the four patients in whom ADC were obtained on follow-up, they were increased by 19% in the head and 17% in the body. DWI may represent a useful adjunct to conventional MRI for identifying acute injury to the hippocampus which results in sclerosis. (orig.)

  5. Lack of potassium channel induces proliferation and survival causing increased neurogenesis and two-fold hippocampus enlargement

    DEFF Research Database (Denmark)

    Almgren, Malin; Persson, Ann-Sophie; Fenghua, Chen

    2007-01-01

    -fold within dentate gyrus (DG), CA2/3, and hilus of 12-week-old mceph/mceph versus wild type mice. In CA1, there was a tendency toward an increase in volume and in number of astrocytes. The volume estimates in newborn and p14 mice suggest that the overgrowth in mceph/mceph hippocampus starts between birth...

  6. The different roles of glucocorticoids in the hippocampus and hypothalamus in chronic stress-induced HPA axis hyperactivity.

    Directory of Open Access Journals (Sweden)

    Li-Juan Zhu

    Full Text Available Hypothalamus-pituitary-adrenal (HPA hyperactivity is observed in many patients suffering from depression and the mechanism underling the dysfunction of HPA axis is not well understood. Chronic stress has a causal relationship with the hyperactivity of HPA axis. Stress induces the over-synthesis of glucocorticoids, which will arrive at all the body containing the brain. It is still complicated whether glucocorticoids account for chronic stress-induced HPA axis hyperactivity and in which part of the brain the glucocorticoids account for chronic stress-induced HPA axis hyperactivity. Here, we demonstrated that glucocorticoids were indispensable and sufficient for chronic stress-induced hyperactivity of HPA axis. Although acute glucocorticoids elevation in the hippocampus and hypothalamus exerted a negative regulation of HPA axis, we found that chronic glucocorticoids elevation in the hippocampus but not in the hypothalamus accounted for chronic stress-induced hyperactivity of HPA axis. Chronic glucocorticoids exposure in the hypothalamus still exerted a negative regulation of HPA axis activity. More importantly, we found mineralocorticoid receptor (MR - neuronal nitric oxide synthesis enzyme (nNOS - nitric oxide (NO pathway mediated the different roles of glucocorticoids in the hippocampus and hypothalamus in regulating HPA axis activity. This study suggests that the glucocorticoids in the hippocampus play an important role in the development of HPA axis hyperactivity and the glucocorticoids in the hypothalamus can't induce hyperactivity of HPA axis, revealing new insights into understanding the mechanism of depression.

  7. Dermatitis and systemic mycosis in lined seahorses Hippocampus erectus associated with a marine-adapted Fusarium solani species complex pathogen

    Science.gov (United States)

    During a 4 month epizootic, 100% of 152 lined seahorses Hippocampus erectus in three separate groups died while in quarantine following shipment to a public aquarium. Twelve animals with skin depigmentation and ulceration were received by the Aquatic Pathology Service, University of Georgia, College...

  8. Research Paper: Cross State-dependent Learning Interaction Between Scopolamine and Morphine in Mice: The Role of Dorsal Hippocampus

    Directory of Open Access Journals (Sweden)

    Morteza Maleki

    2017-05-01

    Conclusion: The current study findings indicated a cross state-dependent learning between SCO and morphine at CA1 level. Therefore, it seems that muscarinic and opioid receptors may act reciprocally on modulation of passive avoidance memory retrieval, at the level of dorsal hippocampus, in mice.

  9. Effects of combined prenatal stress and toluene exposure on apoptotic neurodegeneration in cerebellum and hippocampus of rats

    DEFF Research Database (Denmark)

    Ladefoged, Ole; Hougaard, Karin Sørig; Hass, Ulla

    2004-01-01

    the offspring for developmental neurotoxicity and level of apoptosis in the brain. The number of apoptotic cells in cerebellum postnatal day 22, 24, and 27 and in hippocampus (postnatal day 22, 24, and 27) were counted after visualization by the TUNEL staining or measured by DNA-laddering technique. Caspase-3...

  10. Tramadol Pretreatment Enhances Ketamine-Induced Antidepressant Effects and Increases Mammalian Target of Rapamycin in Rat Hippocampus and Prefrontal Cortex

    Directory of Open Access Journals (Sweden)

    Chun Yang

    2012-01-01

    Full Text Available Several lines of evidence have demonstrated that acute administration of ketamine elicits fast-acting antidepressant effects. Moreover, tramadol also has potential antidepressant effects. The aim of this study was to investigate the effects of pretreatment with tramadol on ketamine-induced antidepressant activity and was to determine the expression of mammalian target of rapamycin (mTOR in rat hippocampus and prefrontal cortex. Rats were intraperitoneally administrated with ketamine at the dose of 10 mg/kg or saline 1 h before the second episode of the forced swimming test (FST. Tramadol or saline was intraperitoneally pretreated 30 min before the former administration of ketamine or saline. The locomotor activity and the immobility time of FST were both measured. After that, rats were sacrificed to determine the expression of mTOR in hippocampus and prefrontal cortex. Tramadol at the dose of 5 mg/kg administrated alone did not elicit the antidepressant effects. More importantly, pretreatment with tramadol enhanced the ketamine-induced antidepressant effects and upregulated the expression of mTOR in rat hippocampus and prefrontal cortex. Pretreatment with tramadol enhances the ketamine-induced antidepressant effects, which is associated with the increased expression of mTOR in rat hippocampus and prefrontal cortex.

  11. Study on cognition disorder and morphologic change of neurons in hippocampus area following traumatic brain injury in rats

    Institute of Scientific and Technical Information of China (English)

    洪军; 崔建忠; 周云涛; 高俊玲

    2002-01-01

    Objective: To explore the correlation between cognition disorder and morphologic change of hippocampal neurons after traumatic brain injury (TBI).   Methods: Wistar rat models with severe TBI were made by Marmarous method. The histopathological change of the neurons in the hippocampus area were studied with hematoxylin-eosin (HE) staining and terminal deoxynucleotidyl transferase-mediated X-dUPT nick end labeling (TUNEL), respectively. The cognitive function was evaluated with the Morris water maze test.   Results: The comprehensive neuronal degeneration and necrosis could be observed in CA2-3 regions of hippocampus at 3 days after injury. Apoptotic positive neurons in CA2-4 regions of hippocampus and dentate gyrus increased in the injured group at 24 hours following TBI. They peaked at 7 days and then declined. Significant impairment of spatial learning and memory was observed after injury in the rats.   Conclusions: The rats have obvious disorders in spatial learning and memory after severe TBI. Meanwhile, delayed neuronal necrosis and apoptosis can be observed in the neurons in the hippocampus area. It suggests that delayed hippocampal cell death may contribute to the functional deficit.

  12. Transient global amnesia: increased signal intensity in the right hippocampus on diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, M.; Sakamoto, S.; Ishii, K. [Division of Neuroimaging Research, Hyogo Institute for Aging Brain and Cognitive Disorders (Japan); Imamura, T.; Kazui, H.; Mori, E. [Division of Clinical Neurosciences, Hyogo Institute for Aging Brain and Cognitive Disorders, Hyogo (Japan)

    2002-03-01

    We report on a patient with pure transient global amnesia (TGA) whose magnetic resonance imaging (MRI) demonstrated a small region of increased signal intensity in the right hippocampus on diffusion-weighted imaging (DWI). DWI was sensitive and useful for evaluating the early stage of TGA and might help to explain the pathophysiology of TGA. (orig.)

  13. Transient global amnesia: increased signal intensity in the right hippocampus on diffusion-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Matsui, M.; Sakamoto, S.; Ishii, K.; Imamura, T.; Kazui, H.; Mori, E.

    2002-01-01

    We report on a patient with pure transient global amnesia (TGA) whose magnetic resonance imaging (MRI) demonstrated a small region of increased signal intensity in the right hippocampus on diffusion-weighted imaging (DWI). DWI was sensitive and useful for evaluating the early stage of TGA and might help to explain the pathophysiology of TGA. (orig.)

  14. Tooth loss early in life suppresses neurogenesis and synaptophysin expression in the hippocampus and impairs learning in mice.

    Science.gov (United States)

    Kubo, Kin-Ya; Murabayashi, Chika; Kotachi, Mika; Suzuki, Ayumi; Mori, Daisuke; Sato, Yuichi; Onozuka, Minoru; Azuma, Kagaku; Iinuma, Mitsuo

    2017-02-01

    Tooth loss induced neurological alterations through activation of a stress hormone, corticosterone. Age-related hippocampal morphological and functional changes were accelerated by early tooth loss in senescence-accelerated mouse prone 8 (SAMP8). In order to explore the mechanism underlying the impaired hippocampal function resulting from early masticatory dysfunction due to tooth loss, we investigated the effects of early tooth loss on plasma corticosterone levels, learning ability, neurogenesis, and synaptophysin expression in the hippocampus later in life of SAMP8 mice. We examined the effects of tooth loss soon after tooth eruption (1 month of age) on plasma corticosterone levels, learning ability in the Morris water maze, newborn cell proliferation, survival and differentiation in the hippocampal dentate gyrus, and synaptophysin expression in the hippocampus of aged (8 months of age) SAMP8 mice. Aged mice with early tooth loss exhibited increased plasma corticosterone levels, hippocampus-dependent learning deficits in the Morris water maze, decreased cell proliferation, and cell survival in the dentate gyrus, and suppressed synaptophysin expression in the hippocampus. Newborn cell differentiation in the hippocampal dentate gyrus, however, was not affected by early tooth loss. These findings suggest that learning deficits in aged SAMP8 mice with tooth loss soon after tooth eruption are associated with suppressed neurogenesis and decreased synaptophysin expression resulting from increased plasma corticosterone levels, and that long-term tooth loss leads to impaired cognitive function in older age. Copyright © 2016. Published by Elsevier Ltd.

  15. iTRAQ proteomic analysis of the hippocampus in a rat model of nicotine-induced conditioned place preference.

    Science.gov (United States)

    Zhu, Beibei; Li, Xiangyu; Chen, Huan; Wang, Hongjuan; Zhu, Xinchao; Hou, Hongwei; Hu, Qingyuan

    2017-05-13

    Repeated exposures to nicotine are known to result in persistent changes in proteins expression in addiction-related brain regions, such as the striatum, nucleus accumbens and prefrontal cortex, but the changes induced in the protein content of the hippocampus remain poorly studied. This study established a rat model of nicotine-induced conditioned place preference (CPP), and screened for proteins that were differentially expressed in the hippocampus of these rats using isobaric tags for relative and absolute quantitation labeling (iTRAQ) coupled with 2D-LC MS/MS. The nicotine-induced CPP was established by subcutaneously injecting rats with 0.2 mg/kg nicotine. Relative to the control (saline) group, the nicotine group showed 0.67- and 1.5-fold changes in 117 and 10 hippocampal proteins, respectively. These differentially expressed proteins are mainly involved in calcium-mediated signaling, neurotransmitter transport, GABAergic synapse function, long-term synaptic potentiation and nervous system development. Furthermore, RT-PCR was used to confirmed the results of the proteomic analysis. Our findings identify several proteins and cellular signaling pathways potentially involved in the molecular mechanisms in the hippocampus that underlie nicotine addiction. These results provide insights into the mechanisms of nicotine treatment in hippocampus. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Amygdala and hippocampus volumes are differently affected by childhood trauma in patients with bipolar disorders and healthy controls.

    Science.gov (United States)

    Janiri, Delfina; Sani, Gabriele; Rossi, Pietro De; Piras, Fabrizio; Iorio, Mariangela; Banaj, Nerisa; Giuseppin, Giulia; Spinazzola, Edoardo; Maggiora, Matteo; Ambrosi, Elisa; Simonetti, Alessio; Spalletta, Gianfranco

    2017-08-01

    Volumetric studies on deep gray matter structures in bipolar disorder (BP) have reported contrasting results. Childhood trauma, a relevant environmental stressor for BP, could account for the variability of the results, modulating differences in the amygdala and hippocampus in patients with BP compared with healthy controls (HC). Our study aimed to test this hypothesis. We assessed 105 outpatients, diagnosed with bipolar disorder type I (BP-I) or bipolar disorder type II (BP-II) according to DSM-IV-TR criteria, and 113 HC subjects. History of childhood trauma was obtained using the Childhood Trauma Questionnaire (CTQ). High-resolution magnetic resonance imaging was performed on all subjects and volumes of the amygdala, hippocampus, nucleus accumbens, caudate, pallidum, putamen, and thalamus were measured using FreeSurfer. Patients with BP showed a global reduction of deep gray matter volumes compared to HCs. However, childhood trauma modulated the impact of the diagnosis specifically on the amygdala and hippocampus. Childhood trauma was associated with bilateral decreased volumes in HCs and increased volumes in patients with BP. The results suggest that childhood trauma may have a different effect in health and disease on volumes of gray matter in the amygdala and hippocampus, which are brain areas specifically involved in response to stress and emotion processing. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Effects of developmental exposure to a Commercial PBDE mixture (DE-71) on protein networks in the rat Cerebellum and Hippocampus

    Science.gov (United States)

    Title (20 words): Effects of developmental exposure to a Commercial PBDE mixture (DE-71) on protein networks in the rat Cerebellum and Hippocampus. Introduction (120 words): Polybrominated diphenyl ethers (PBDE5) possess neurotoxic effects similar to those of PCBs. The cellular a...

  18. The Role of the Hippocampus in Retaining Relational Information across Short Delays: The Importance of Memory Load

    Science.gov (United States)

    Jeneson, Annette; Mauldin, Kristin N.; Hopkins, Ramona O.; Squire, Larry R.

    2011-01-01

    Patients with hippocampal damage are sometimes impaired at remembering information across delays as short as a few seconds. How are these impairments to be understood? One possibility is that retention of some kinds of information is critically dependent on the hippocampus, regardless of the retention interval and regardless of whether the task…

  19. Electrophysiological and neurochemical changes in the rat hippocampus after in vitro and in vivo treatments with cocaine

    International Nuclear Information System (INIS)

    Yasuda, R.P.

    1986-01-01

    The in vitro and in vivo effects of cocaine in the noradrenergic pathway in the rat hippocampus were examined. Although the blockade of [ 3 H]-norepinephrine-uptake by cocaine has been well-characterized in both the central and peripheral nervous systems, investigations characterizing the electrophysiological effects of cocaine in the central nervous system have been limited. The first part of this thesis examines the relationship between the ability of cocaine to potentiate the electrophysiological response to norepinephrine (NE) and the ability of cocaine to block noradrenergic high affinity uptake in rat hippocampal slices. The second part of this thesis examines the effects of the repeated administration of cocaine on noradrenergic pre- and postsynaptic function and receptors of the rat hippocampus. These studies demonstrate that after repeated administration of cocaine (10 mg/kg/day) for 8 and 14 days there is a 50% decrease in NE high affinity uptake in the rat hippocampus. This was accompanied by a 40% increase in a binding site for NE uptake inhibitors at 14 days. In contrast to these effects, there was no effect on β-adrenergic receptor number or the isoproterenol induced electrophysiological responsiveness in the rat hippocampus. The conclusion of these studies is that the repeated administration of cocaine has a greater effect on presynaptic targets in the noradrenergic system than on postsynaptic neurons

  20. In vivo cellular uptake of glutamate is impaired in the rat hippocampus during and after transient cerebral ischemia

    DEFF Research Database (Denmark)

    Bruhn, T; Christensen, Thomas; Diemer, Nils Henrik

    2001-01-01

    Using microdialysis in CA1 of the rat hippocampus, we studied the effect of transient cerebral ischemia on in vivo uptake and on extracellular levels of glutamate during, and at different time points after ischemia. (3)H-D-aspartate (test substance), and (14)C-mannitol (reference substance), were...