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
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.
Huixian Zhang; Geng Qin; Yanhong Zhang; Shuisheng Li; Qiang Lin
ABSTRACT Leptin is an essential hormone for the regulation of energy metabolism and food intake in vertebrate animals. To better understand the physiological roles of leptin in nutrient regulation in paternal ovoviviparous fish (family Syngnathidae), the present study cloned the full-length of leptin-a and leptin receptor (lepr) genes in lined seahorse (Hippocampus erectus). Results showed that there was a 576-bp intron between two exons in leptin-a gene but no leptin-b gene in seahorse. Alth...
Lin, Qiang; Li, Gang; Qin, Geng; Lin, Junda; Huang, Liangmin; Sun, Hushan; Feng, Peiyong
Summary Seahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1st birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6th birth (465.9±136.4 per brood) (Pseahorses H. erectus increased with the brood pouch development. PMID:23213429
Zhang, Yanhong; Zhang, Huixian; Lin, Qiang; Huang, Liangmin
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%).
Full Text Available Leptin is an essential hormone for the regulation of energy metabolism and food intake in vertebrate animals. To better understand the physiological roles of leptin in nutrient regulation in paternal ovoviviparous fish (family Syngnathidae, the present study cloned the full-length of leptin-a and leptin receptor (lepr genes in lined seahorse (Hippocampus erectus. Results showed that there was a 576-bp intron between two exons in leptin-a gene but no leptin-b gene in seahorse. Although the primary amino acid sequence conservation of seahorse leptin-a was very low, the 3-D structure modeling of seahorse leptin-a revealed strong conservation of tertiary structure with other vertebrates. Seahorse leptin-a mRNA was highly expressed in brain, whereas lepr mRNA was mainly expressed in ovary and gill. Interestingly, both leptin-a and lepr mRNA were expressed in the brood pouch of male seahorse, suggesting the leptin system plays a role during the male pregnancy. Physiological experiments showed that the expression of hepatic leptin-a and lepr mRNA in unfed seahorses was significantly higher than that in those fed 100%, as well as 60%, of their food during the fasting stage, showing that seahorse might initiate the leptin system to regulate its energy metabolism while starving. Moreover, the expression of leptin-a in the brood pouch of pregnant seahorse was significantly upregulated compared with non-pregnant seahorse, whereas the expression of lepr was downregulated, suggesting that the leptin system might be involved in the male pregnancy. In conclusion, the leptin system plays a role in the energy metabolism and food intake, and might provide new insights into molecular regulation of male pregnancy in seahorse.
Zhang, Huixian; Qin, Geng; Zhang, Yanhong; Li, Shuisheng; Lin, Qiang
Leptin is an essential hormone for the regulation of energy metabolism and food intake in vertebrate animals. To better understand the physiological roles of leptin in nutrient regulation in paternal ovoviviparous fish (family Syngnathidae), the present study cloned the full-length of leptin-a and leptin receptor (lepr) genes in lined seahorse (Hippocampus erectus). Results showed that there was a 576-bp intron between two exons in leptin-a gene but no leptin-b gene in seahorse. Although the primary amino acid sequence conservation of seahorse leptin-a was very low, the 3-D structure modeling of seahorse leptin-a revealed strong conservation of tertiary structure with other vertebrates. Seahorse leptin-a mRNA was highly expressed in brain, whereas lepr mRNA was mainly expressed in ovary and gill. Interestingly, both leptin-a and lepr mRNA were expressed in the brood pouch of male seahorse, suggesting the leptin system plays a role during the male pregnancy. Physiological experiments showed that the expression of hepatic leptin-a and lepr mRNA in unfed seahorses was significantly higher than that in those fed 100%, as well as 60%, of their food during the fasting stage, showing that seahorse might initiate the leptin system to regulate its energy metabolism while starving. Moreover, the expression of leptin-a in the brood pouch of pregnant seahorse was significantly upregulated compared with non-pregnant seahorse, whereas the expression of lepr was downregulated, suggesting that the leptin system might be involved in the male pregnancy. In conclusion, the leptin system plays a role in the energy metabolism and food intake, and might provide new insights into molecular regulation of male pregnancy in seahorse. © 2016. Published by The Company of Biologists Ltd.
Fogelson, S B; Yanong, R P E; Kane, A; Teal, C N; Berzins, I K; Smith, S A; Brown, C; Camus, A
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.
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...
Woodall, L C; Koldewey, H J; Santos, S V; Shaw, P W
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.
Zhang, Huixian; Qin, Geng; Sun, Jinhui; Zhang, Bo; Lin, Qiang
The peptide cholecystokinin (CCK) plays an important role in the regulation of vertebrate appetite and feeding behaviour. In the present study, the full-length cDNA and genomic DNA sequences of two CCK precursors were cloned and analysed in the Syngnathidae fish, the lined seahorse (Hippocampus erectus). Both CCK1 and CCK2 in the seahorse consist of four exons. The sequence of the octapeptide of seahorse CCK1 (DYMGWMDF) was the same as that of the chicken and human, while the octapeptide of seahorse CCK2 (DYEGWMDF) was unique among vertebrates. According to the phylogenetic analysis, two types of CCKs were produced by teleost-specific genome duplication (TGD). Both CCK1 and CCK2 were highly expressed in the brain, while detectable amounts of CCK1 mRNA in the brood pouch and CCK2 mRNA in the intestine were also found. Both CCK1 and CCK2 mRNA levels significantly increased during the transition from endogenous to exogenous nutrition. Additionally, fasting induced a significant increase in the CCK1 mRNA expression in the brain of juvenile seahorses but had no effect on CCK2 transcript levels. In addition, the CCK1 and CCK2 mRNA levels in the seahorse brain significantly increased after a high-temperature treatment. Thus, the mRNA expression of CCK had obvious tissue specificities and this preliminary study opens new avenues for further functional studies on the endocrine regulations of CCK in the transition from endogenous to exogenous nutrition, food intake regulation and metabolism in the seahorse. Copyright © 2017 Elsevier Inc. All rights reserved.
Lin, Tingting; Zhang, Dong; Liu, Xin; Xiao, Dongxue
Enteritis has been increasingly recognized as one of the major obstacles for the lined seahorse Hippocampus erectus mass culture success. In the present study, the intestinal bacteria strains of the lined seahorses H. erectus suffered from enteritis were isolated, then their pathogenicities were confirmed by artificial infection, and one pathogenic bacteria strain named DS3 was obtained. The median lethal dose (LD50) of strain DS3 for 10 days was determined. The seahorses with different infection levels of uninfected (control), early stage of infection (ESI) and late stage of infection (LSI) were respectively sampled at 0, 3, 6 and 9 days post infection, and 12 immune parameters in the plasma were analyzed. The strain DS3 identified with a biochemical test combined with a molecular method was Vibrio parahaemolyticus, and its LD50 for 10 days was 1.3 × 10(3) cfu/fish. Six parameters including monocytes/leucocytes, leucocytes phagocytic rate, interleukin-2, interferon-α, lysozyme and immunoglobulin M exhibited a generally similar variation trend: highest in the control, second in the ESI and lowest in the LSI throughout the entire experiment. In view of the infection level of V. parahaemolyticus to H. erectus is largely decided by the seahorse's own immune capacity, therefore, these immune parameters were high in the non- or slightly infected seahorses, and low in the severely infected individuals may be an indicator for immune level. These immune parameters may be reliable indicators for the juvenile and broodstock quality assessment. Moreover, clarification of the enteritis pathogen also provides guidances for targeted medicine choice for the lined seahorse. Copyright © 2016 Elsevier Ltd. All rights reserved.
Seahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1st birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6th birth (465.9±136.4 per brood (P<0.001. The offspring survivorship and growth rate increased with the births. The fecundity was positively correlated with the length of brood pouches of males and trunk of females. The fecundity of 1-year old male and 2-year old female pairs was significantly higher than that from 1-year old couples (P<0.001. The brood size (552.7±150.4 of the males who mated with females that were isolated for the gamete-preparation, was larger than those (467.8±141.2 from the long-term pairs (P<0.05. Moreover, the offspring from the isolated females had higher survival and growth rates. Our results showed that the potential reproductive rate of seahorses H. erectus increased with the brood pouch development.
Lin, Tingting; Wang, Changbo; Liu, Xin; Gao, Fen; Xiao, Dongxue; Zhang, Dong; Zhu, Xialian
Gastrointestinal disease is one of the most serious diseases in cultured seahorse juveniles. Treatment with antimicrobials of live food (i.e. copepods and Artemia) that is used to feed the juveniles may be a promising measure to alleviate the occurrence of gastrointestinal disease. However, relevant investigations are rare. In the present study, we first investigated the antimicrobial efficacies on bacteria within copepods that were treated with 4 antimicrobials, including 3 antibiotics (i.e. enrofloxacin hydrochloride, oxytetracycline and rifampicin [RFP]) that are approved for use in aquaculture and 1 disinfectant (i.e. povidone iodine). We then assessed the effects of copepods treated with the antimicrobial that had the best antimicrobial efficacy on survival, growth performance and immune capacity of juvenile lined seahorses Hippocampus erectus. The results showed that RFP had the best antimicrobial efficacy on both Pseudoalteromonas spp. and Vibrio spp., 2 dominant bacteria with potential pathogenicity within the copepods; the proper concentration of RFP was 6 mg l-1. Moreover, H. erectus juveniles fed with RFP-treated copepods demonstrated an improved survivorship and immune capacity and had a lower abundance of pathogenic bacteria within their gastrointestinal tracts compared to juveniles fed with untreated copepods. These results suggest that treating live food with RFP is a potential measure for reducing the incidence of gastrointestinal disease in seahorse juveniles.
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 ...
Luo, Wei; Wang, Xin; Qu, Hongyue; Qin, Geng; Zhang, Huixian; Lin, Qiang
The major histocompatibility complex (MHC) genes are crucial in the adaptive immune system, and the gene duplication of MHC in animals can generally result in immune flexibility. In this study, we found that the lined seahorse (Hippocampus erectus) has only one gene copy number (GCN) of MHC IIα and IIβ, which is different from that in other teleosts. Together with the lack of spleen and gut-associated lymphatic tissue (GALT), the seahorse may be referred to as having a partial but natural "immunodeficiency". Highly variable amino acid residues were found in the IIα and IIβ domains, especially in the α1 and β1 domains with 9.62% and 8.43% allelic variation, respectively. Site models revealed seven and ten positively selected positions in the α1 and β1 domains, respectively. Real-time PCR experiments showed high expression levels of the MHC II genes in intestine (In), gill (Gi) and trunk kidney (TK) and medium in muscle (Mu) and brood pouch (BP), and the expression levels were significantly up-regulated after bacterial infection. Specially, relative higher expression level of both MHC IIα and IIβ was found in Mu and BP when compared with other fish species, in which MHC II is expressed negligibly in Mu. These results indicate that apart from TK, Gi and In, MU and BP play an important role in the immune response against pathogens in the seahorse. In conclusion, high allelic variation and strong positive selection in PBR and relative higher expression in MU and BP are speculated to partly compensate for the immunodeficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.
Anderson, Paul August
Loud noise in aquaria represents a cacophonous environment for captive fishes. I tested the effects of loud noise on acoustic communication, feeding behavior, courtship behavior, and the stress response of the lined seahorse, Hippocampus erectus. Total Root Mean Square (RMS) power of ambient noise to which seahorses are exposed in captivity varies widely but averages 126.1 +/- 0.8 deciBels with reference to one micropascal (dB re: 1 muPa) at the middle of the water column and 133.7 +/- 1.1 dB at the tank bottom, whereas ambient noise in the wild averages 119.6 +/- 3.5 dB. Hearing sensitivity of H. erectus, measured from auditory evoked potentials, demonstrated maximum spectrum-level sensitivities of 105.0 +/- 1.5 dB and 3.5 x 10-3 + 7.6 x 10-4 m/s2 at 200 Hz; which is characteristic of hearing generalists. H. erectus produces acoustic clicks with mean peak spectrum-level amplitudes of 94.3 +/- 0.9 dB at 232 +/- 16 Hz and 1.5 x 10 -3 +/- 1.9 x 10-4 m/s2 at 265 +/- 22 Hz. Frequency matching of clicks to best hearing sensitivity, and estimates of audition of broadband signals suggest that seahorses may hear conspecific clicks, especially in terms of particle motion. Behavioral investigations revealed that clicking did not improve prey capture proficiency. However, animals clicked more often as time progressed in a courtship sequence, and mates performed more courtship behaviors with control animals than with muted animals, lending additional evidence to the role of clicking as an acoustic signal during courtship. Despite loud noise and the role of clicking in communication, masking of the acoustic signal was not demonstrated. Seahorses exposed to loud noise in aquaria for one month demonstrated physiological, chronic stress responses: reduced weight and body condition, and increased heterophil to lymphocyte ratio. Behavioral alterations were characterized by greater mean and variance of activity among animals housed in loud tanks in the first week, followed by
Rose, Emily; Small, Clayton M; Saucedo, Hector A; Harper, Cristin; Jones, Adam G
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: firstname.lastname@example.org.
Planas, Miguel; Chamorro, Alexandro; Quintas, Patricia; Vilar, Antonio
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...
Qin, Geng; Johnson, Cara; Zhang, Yuan; Zhang, Huixian; Yin, Jianping; Miller, Glen; Turingan, Ralph G; Guisbert, Eric; Lin, Qiang
Inshore-offshore migration occurs frequently in seahorse species either because of prey opportunities or because it is driven by reproduction, and variations in water temperature may dramatically change migratory seahorse behavior and physiology. The present study investigated the behavioral and physiological responses of the lined seahorse Hippocampus erectus under thermal stress and evaluated the potential effects of different temperatures on its reproduction. The results showed that the thermal tolerance of the seahorses was time dependent. Acute thermal stress (30°C, 2-10 hours) increased the basal metabolic rate (breathing rate) and the expression of stress response genes ( Hsp genes) significantly and further stimulated seahorse appetite. Chronic thermal treatment (30°C, 4 weeks) led to a persistently higher basal metabolic rate, higher stress response gene expression, and higher mortality, indicating that the seahorses could not acclimate to chronic thermal stress and might experience massive mortality due to excessive basal metabolic rates and stress damage. Additionally, no significant negative effects on gonad development or reproductive endocrine regulation genes were observed in response to chronic thermal stress, suggesting that seahorse reproductive behavior could adapt to higher-temperature conditions during migration and within seahorse breeding grounds. In conclusion, this simulation experiment indicated that temperature variations during inshore-offshore migration have no effect on reproduction but promote basal metabolic rates and stress responses significantly. Therefore, we suggest that the high observed tolerance of seahorse reproduction was in line with the inshore-offshore reproductive migration pattern of lined seahorse. © 2018. Published by The Company of Biologists Ltd.
Novelli, B; Otero-Ferrer, F; Socorro, J A; Caballero, M J; Segade-Botella, A; Molina Domínguez, L
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.
Lin, Tingting; Zhang, Dong; Liu, Xin; Xiao, Dongxue
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.
Wang, Lei; Chen, Zaizhong; Leng, Xiangjun; Gao, Jianzhong; Chen, Xiaowu; Li, Zhongpu; Sun, Peiying; Zhao, Yuming
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.
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
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.
Wilson, A B; Martin-Smith, K M
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.
Delunardo, Frederico Augusto Cariello; de Carvalho, Luciano Rodrigues; da Silva, Bruno Ferreira; Galão, Michel; Val, Adalberto Luís; Chippari-Gomes, Adriana R
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.
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...
S. R. M. Tabugo-Rico
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.
Zhang, Ning; Xu, Bin; Mou, Chunyan; Yang, Wenli; Wei, Jianwen; Lu, Liang; Zhu, Junjie; Du, Jingchun; Wu, Xiaokun; Ye, Lanting; Fu, Zhiyan; Lu, Yang; Lin, Jianghai; Sun, Zizi; Su, Jing; Dong, Meiling; Xu, Anlong
A cDNA library of male Chinese seahorse (Hippocampus kuda Bleeker) was constructed to investigate the molecular profile of seahorse as one of the most famous traditional Chinese medicine materials, and to reveal immunological and physiological mechanisms of seahorse as one of the most primitive vertebrates at molecular level. A total of 3372 expressed sequence tags (ESTs) consisting of 1911 unique genes (345 clusters and 1566 singletons) were examined in the present study. Identification of the genes related to immune system, paternal brooding and physiological regulation provides not only valuable insights into the molecular mechanism of immune system in teleost fish but also plausible explanations for pharmacological activities of Chinese seahorse. Furthermore, the occurrence of high prevalent C-type lectins suggested that a lectin-complement pathway might exert a more dominant function in the innate immune system of teleost than mammal. Carbohydrate recognition domain (CRD) without a collagen-like region in the lectins of seahorse was likely an ancient characteristic of lectins similar to invertebrates.
Kawaguchi, Mari; Okubo, Ryohei; Harada, Akari; Miyasaka, Kazuki; Takada, Kensuke; Hiroi, Junya; Yasumasu, Shigeki
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
Pawar, H.B.; Sanaye, S.V.; Murugan, A.; Sreepada, R.A.; Tanu
the supply, with at least 25 million seahorses (>70 tons dry weight) traded globally (Project Seahorse, 2006; Salin and Mohankumran, 2006). High exploitation rates in India, Indonesia, Philippines, Thailand, and Vietnam resulted in a decline of 25... and ecology of seahorses: implications for conservation and management. J. Fish Biol., 65:1-61. Garcia L.M.B., Hilomen-Garcia G.V. and R.L.M, Calibara, 2010. Culturing seahorse (Hippocampus barbouri) in illuminated cages with supplementary Acetes feeding...
Saavedra, M; Masdeu, M; Hale, P; Sibbons, C M; Holt, W V
Seahorses populations in the wild have been declining and to restore them a better knowledge of seahorse reproduction is required. This study examines the effect of dietary quality on seahorse fecundity and egg quality. Two different diets were tested with Hippocampus kuda females: frozen mysis (control) and frozen mysis enriched with a liposome spray containing essential fatty acids. Diets were given to females (two groups of five) over a seven week period. After this period, males (fed the control diet) and females were paired and the eggs dropped by the females were collected. Fatty acid profile were analysed and eggs were counted and measured. Results showed that females fed on enriched mysis had larger eggs and that these had a higher content of total polyunsaturated fatty acids. The size of the egg was especially affected in the first spawn, where egg size for females fed the enriched diet was significantly higher than the egg size from control females. This effect was reduced in the following spawning where no significant differences were found. Egg size is an important quality descriptor as seahorse juveniles originating from smaller eggs and/or eggs of poor quality will have less chances of overcoming adverse conditions in the wild and consequently have lower survival and growth rates. This study shows that enriching frozen mysis with polyunsaturated fatty acids increases egg size and egg quality of H. kuda. Copyright © 2013 Elsevier B.V. All rights reserved.
Fedrizzi, Nathan; Stiassny, Melanie L J; Boehm, J T; Dougherty, Eric R; Amato, George; Mendez, Martin
The dwarf seahorse (Hippocampus zosterae) is widely distributed throughout near-shore habitats of the Gulf of Mexico and is of commercial significance in Florida, where it is harvested for the aquarium and curio trades. Despite its regional importance, the genetic structure of dwarf seahorse populations remains largely unknown. As an aid to ongoing conservation efforts, we employed three commonly applied mtDNA markers (ND4, DLoop and CO1) to investigate the genetic structuring of H. zosterae in Florida using samples collected throughout its range in the state. A total of 1450 bp provided sufficient resolution to delineate four populations of dwarf seahorses, as indicated by significant fixation indices. Despite an overall significant population structure, we observed evidence of interbreeding between individuals from geographically distant sites, supporting the hypothesis that rafting serves to maintain a degree of population connectivity. All individuals collected from Pensacola belong to a single distinct subpopulation, which is highly differentiated from the rest of Floridian dwarf seahorses sampled. Our findings highlight the utility of mtDNA markers in evaluating barriers to gene flow and identifying genetically distinct populations, which are vital to the development of comprehensive conservation strategies for exploited taxa.
de la Nuez Hernández, Daril; Pastor Gutiérrez, Lourdes; Pérez Angulo, Alejandro; Piloto Cubero, Yuliet; Corrada Wong, Raúl Igor
Fish populations of the Syngnathidae family, including the charismatic seahorse, have significantly declined worldwide during the last decades. Up to now, these populations have been poorly researched in their habitat in Cuba. The objective of this study was to determinate site fidelity and home range of the longsnout seahorse (Hippocampus reidi Ginsburg, 1933), which has been poorly studied and has been classified as a Data Deficient (DD) species by the IUCN. Sampling was conducted between A...
Aaron Premnath LIPTON
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.
Li, Yong; Qian, Zhong-Ji; Kim, Se-Kwon
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.
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
Wang, Bo; Zhang, Yanhong; Zhang, Huixian; Lin, Qiang
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%.
Zhang, Huixian; Zhang, Yanhong; Lin, Qiang
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%).
Wang, Xin; Zhang, Yanhong; Zhang, Huixian; Meng, Tan; Lin, Qiang
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%).
Yuan Yuan Zhang; Bo-Mi Ryu; Zhong-Ji Qian
Seahorse has been used as medicine in Asian countries such as China, Korea, Japan and Vietnam for thousands of years. However, in western countries, the ecology of seahorse has been a focus of attention of many researchers for years. The seahorse aquaculture is popular with aqua farm worldwide for the sake of the increased demand of seahorse. This review described the biology, aquaculture and medical use of seahorse. To present the ecology and highlight the role of seahorse in traditional med...
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
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.
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.
Roos, Gert; Van Wassenbergh, Sam; Herrel, Anthony; Aerts, Peter
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.
Zhang, Yanhong; Pham, Nancy Kim; Zhang, Huixian; Lin, Junda; Lin, Qiang
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.
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.
Ko, Jiyeon; Wan, Qiang; Bathige, S D N K; Lee, Jehee
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.
Pangestuti, Ratih; Ryu, Bomi; Himaya, Swa; Kim, Se-Kwon
Hippocampus trimaculatus is one of the most heavily traded seahorse species for traditional medicine purposes in many countries. In the present study, we showed neuroprotective effects of peptide derived from H. trimaculatus against amyloid-β42 (Aβ42) toxicity which are central to the pathogenesis of Alzheimer's diseases (AD). Firstly, H. trimaculatus was separately hydrolyzed by four different enzymes and tested for their protective effect on Aβ42-induced neurotoxicity in differentiated PC12 cells. Pronase E hydrolysate exerted highest protection with cell viability value of 88.33 ± 3.33 %. Furthermore, we used response surface methodology to optimize pronase E hydrolysis conditions and found that temperature at 36.69 °C with the hydrolysis time 20.01 h, enzyme to substrate (E/S) ratio of 2.02 % and pH 7.34 were the most optimum conditions. Following several purification steps, H. trimaculatus-derived neuroprotective peptides (HTP-1) sequence was identified as Gly-Thr-Glu-Asp-Glu-Leu-Asp-Lys (906.4 Da). HTP-1 protected PC12 cells from Aβ42-induced neuronal death with the cell viability value of 85.52 ± 2.22 % and up-regulated pro-survival gene (Bcl-2) expressions. These results suggest that HTP-1 has the potential to be used in treatment of neurodegenerative diseases, particularly AD. Identification, characterization, and synthesis of bioactive components derived from H. trimaculatus have the potential to replace or at least complement the use of seahorse as traditional medicine, which further may become an approach to minimize seahorse exploitation in traditional medicine.
Alexandre C. Siqueira
Full Text Available ABSTRACT Estimating population parameters is essential for understanding the ecology of species, which ultimately helps to assess their conservation status. The seahorse Hippocampus reidi is directly exposed to anthropogenic threats along the Brazilian coast, but the species still figures as Data Deficient (DD at IUCN’s Red List. To provide better information on the ecology of this species, we studied how population parameters vary over time in a natural subtropical environment. By combing mark-recapture models for open and closed populations, we estimated abundance, survival rate, emigration probability, and capture probability. We marked 111 individuals, which showed a 1:1 sex ratio, and an average size of 10.5 cm. The population showed high survival rate, low temporary emigration probability and variable capture probability and abundance. Our models considering relevant biological criteria illuminate the relatively poorly known population ecology and life history of seahorses. It is our hope that this study inspires the use of mark-recapture methods in other populations of H. reidi in a collective effort to properly assess their conservation status.
Novelli, B; Otero Ferrer, F; Socorro, J A; Molina Domínguez, L
Fertilized and unfertilized eggs and embryos of the longsnout seahorse Hippocampus reidi were collected at different stages of development and provided the basis for a description of morphological development from fertilization until release from the paternal pouch. Images of fertilized eggs, as well as their rupture after a few minutes in seawater are reported for the first time. The yolk sac transitioned from ovoid to spherical shape and was reabsorbed progressively until release. The tail began rising from the surface of the deuteroplasm while embryos were in the egg envelope. Embryos lacked a primordial fin fold and developed some species characteristics, such as rays in the dorsal fin, before resorption of the yolk sac. At release, juvenile seahorses were in an advanced stage of development even if they lacked important adult characteristics, such as ring plates and coronet. The tail was not prehensile in juveniles at release; a small caudal fin was present, although this fin is lost in adults. This article is protected by copyright. All rights reserved.
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.
Liu, Shuaishuai; Zhang, Yanhong; Wang, Changming; Lin, Qiang
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.
Garcia-Manchón, J; Socorro-Cruz, J; Segade Botella, A; Otero-Ferrer, F; Mesa, A; Molina Domínguez, L
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.
Full Text Available Globally, wild seahorse populations are threatened due to, habitat destruction and unsustainable human exploitation among others. Furthermore, aquaculture-based mass-scale rearing is still uncommon due to the low survival rates of seahorse juveniles and exceptionally high feed costs. Previous studies have demonstrated the importance of both highly unsaturated fatty acid (HUFA supplies and a copepod-based rearing for seahorse survival and growth. As the latter is expensive, the question arises as to how high survival rates of seahorse juveniles can be assured under low- to moderate-cost feed regimes. In particular, it remains unknown whether the diet species or their dietary HUFA profiles determine the successful development of seahorse fry.Therefore, the aims of this study were to assess the dependence of growth and survival rates of Hippocampus reidi brood on the animal feed and to infer the impact of feed species vs. dietary HUFA profiles on juvenile growth. A nutrition experiment was conducted where juveniles were treated either with enriched Artemia nauplii (low-cost diet Art or with a mixed diet of Artemia and copepods (moderate-cost diet Art/Cop. Larval survival and growth were analyzed using Cox proportional-hazard and mixed linear model analyses. We found that i both diets enabled good survival, ii diet Art/Cop resulted in superior weight and height growth, and iii the differential effects of diets Art/Cop and Art cannot be explained by their different HUFA compositions alone.From an economical point of view, our findings of high survival rates and relatively high growth rates with the medium-cost treatment Art/Cop may open new possibilities for the large-scale rearing of seahorses. Even the application of a low-cost Art diet might be appropriate for seahorse aquacultures as both survival and growth rates are only marginally lower compared to the former diet.
Lourie, S A; Green, D M; Vincent, A C J
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.
Murugan, A.; Dhanya, S.; Sreepada, R.A.; Rajagopal, S.; Balasubramanian, T.
ornamental fish markets (Project Seahorse, 2006). 3 Compared to the proposition of mass culture of other seahorse species, H. trimaculatus, inhabiting different geographical regions, has not been thought of seriously from a commercial standpoint...
Lin, Tingting; Liu, Xin; Xiao, Dongxue; Zhang, Dong
To better understand the endocrine- and immune-response pattern during reproduction in a fish species having parental care behaviors and also to accumulate the endocrine- and immune-related data for future explanations of the low reproductive efficiency in seahorse species, the variations of immune factors and sex steroids in the plasma of the male lined seahorse Hippocampus erectus at different breeding stages, i.e., pre-pregnancy, pregnancy (early, middle, and late periods), and post-pregnancy, were investigated in the present study. The immune factors included monocytes/leucocytes (M/L), leucocyte phagocytic rate (LPR), immunoglobulin M (Ig M), interleukin-2 (IL-2), interferon-α (IFN-α), and lysozyme (LZM). The sex steroids included testosterone (T), 11-ketotestosterone (11-KT), 11β-hydroxytestosterone (11β-OHT), 17α-methyltestosterone (17α-MT), 17β-estradiol (E2), and 17α-hydroxy-20β-dihydroprogesterone (17α-20β-P). Moreover, the immune metabolic activity of epithelium cells in the brood pouch at different breeding stages was also analyzed through ultrastructural observations of the abundance of cytoplasmic granules, mitochondria, endoplasmic reticulum, lysosomes, and exocytosis. The results show that a higher immune level was observed during pregnancy, particularly in the early and middle periods, and a lower immune level was noted during pre-pregnancy. Correspondingly, the epithelium cells in the brood pouch also showed a stronger immune metabolic activity during pregnancy and weaker activity during pre-pregnancy. Four sex steroids of T, 11β-OHT, 17α-MT, and E2 were higher during pre-pregnancy and lower during post-pregnancy, whereas 11-KT and 17α-20β-P, which were positively correlated with part immune factors, were higher during pregnancy. No negative correlations between sex steroids and immune factors were observed. In conclusion, the higher immune competence during pregnancy may indicate that parental care could improve immunity, which may
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
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.
Aylesworth, L; Lawson, J M; Laksanawimol, P; Ferber, P; Loh, T-L
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.
Planas, M; Quintas, P; Chamorro, A; Silva, C
Knowledge of the biology and ecology of seahorses (Hippocampus spp.) is scarce, but has been increasing in recent years due to their conservation status. Captivity breeding programmes can be a valuable source of information on the reproductive biology of seahorses. A captive broodstock of Hippocampus guttulatus Cuvier 1829 was established in 2006 and kept under natural-like photoperiod and temperature. Female maturation was studied during the whole reproductive season in 2007. Most egg clutches were released from May (17°C; 15L:9D) to October (18°C; 13L:11D), with peak releases occurring in June-August (20°C; 16L:8D-14L:10D). Throughout the study, four egg morphotypes were found; two regression equations were proposed for estimating egg/yolk volume based on measurements of egg and yolk biometrics. Female weight was positively correlated with yolk volume/egg volume ratio (Y(v)/E(v)) (r(s)=0.523, n=21, P<0.05) but not with E(v) or Y(v). Egg dry weight (567±141μg) was correlated with Y(v) (r(s)=0.384, n=31, P<0.05). Mean clutch size and clutch biomass were 242±142 eggs and 137±87mg dry weight, respectively. Clutch size was positively correlated to female weight (r(s)=0.479, n=25, P<0.05). Inter-clutch intervals (days) were affected by temperature (°C) as described by the following equation: Interval=357.55e(-0.1283 Temp). Estimated inter-clutch intervals at 16, 18 and 20°C were 45.9, 35.5 and 27.5 days, respectively. Egg total lipids accounted for 31.9±3.1% dry weight. Absolute lipid content in eggs was correlated with egg dry weight (r(s)=0.907, n=41, P<0.001) and Y(v) (r(s)=0.384, n=41, P<0.5). In decreasing order of relative percentage, the most important fatty acids, were 18:1n9, 16:0, 18:2n6, 20:5n3, 18:0 and 22:6n-3. The level of n-3 HUFA was 18.5±0.7% (38.4±3.3mg/g dry weight). The profile of fatty acids in eggs resembled that displayed by the broodstock diet (enriched adult Artemia). Copyright © 2010 Elsevier B.V. All rights reserved.
Natalie Villar Freret-Meurer
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
Oh, Minyoung; Elvitigala, Don Anushka Sandaruwan; Bathige, S D N K; Lee, Seongdo; Kim, Myoung-Jin; Lee, Jehee
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.
Kolberg, Judy; Busse, Hans-Jürgen; Wilke, Thomas; Schubert, Patrick; Kämpfer, Peter; Glaeser, Stefanie P
An orange-pigmented, Gram-staining-negative, rod-shaped bacterium, designated 96_Hippo_TS_3/13(T) was isolated from the brood pouch of a diseased seahorse male of the species Hippocampus barbouri from the animal facility of the University of Giessen, Germany. Phylogenetic analyses based on the nearly full-length 16S rRNA gene sequence placed strain 96_Hippo_TS_3/13(T) into the monophyletic cluster of the genus Mesonia within the family Flavobacteriaceae. However, the strain shared only 92.2-93.8% sequence similarity to type strains of species of the genus Mesonia, with highest sequence similarity to the type strain of Mesonia aquimarina. Cellular fatty acid analysis showed a Mesonia-typical fatty acid profile including several branched and hydroxyl fatty acids with highest amounts of iso-C15 : 0 (40.9%) followed by iso-C17 : 0 3-OH (14.8%). In the polyamine pattern, sym-homospermidine was predominant. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid. The quinone system contained exclusively menaquinone MK-6. The only identified compound in the polar lipid profile was phosphatidylethanolamine present in major amounts. Additionally, major amounts of an unidentified aminolipid and two unidentified lipids not containing a phosphate group, an amino group or a sugar residue were detected. The genomic G+C content of strain 96_Hippo_TS_3/13(T) was 30 mol%. Based on genotypic, chemotaxonomic and physiological characterizations we propose a novel species of the genus Mesonia, Mesonia hippocampi sp. nov., with strain 96_Hippo_TS_3/13(T) ( = CIP 110839T = LMG 28572(T) = CCM 8557(T)) as the type strain. An emended description of the genus Mesonia is also provided.
Palma, J; Bureau, D P; Andrade, J P
Ontogenetic development of the digestive tract and associated organs in long snout seahorse Hippocampus guttulatus juveniles was morphologically and histologically examined from the time of release from the male's pouch until 72 h after the first meal. When released from the male's pouch, juvenile seahorses are small adult replicates. This means that unlike other teleost fish larvae, the first developmental phase has already taken place, and juveniles are morphologically prepared and able to feed on live prey immediately following parturition. At this stage, the buccopharynx, oesophagus, and intestine already appear to be fully developed. The intestine is divided into the midgut and hindgut by an intestinal valve, and intestinal villi are visible in the midgut. When fed with DHA-Selco(®) enriched Artemia, H. guttulatus juveniles developed a severe condition of overinflation of the gas bladder. The continuous overinflation of the gas bladder forced air into the gut (48 h after the first meal), resulting in overinflation of both the gut and the gas bladder (72 h after the first meal), and death occurred within 120 h after the first meal. When fed natural copepods, H. guttulatus juveniles continued a normal feeding activity with no signs of intestinal disorders, and the gas bladder and intestine maintained their normal shape. This is the first study to positively associate gas bladder overinflation of juvenile seahorses with nutritionally unbalanced diets, and not to gas supersaturation alone. It is therefore necessary to develop more adequate feed and/or enrichment products to improve the survival of juvenile seahorses in captivity.
Full Text Available Estudiamos la fecundidad, supervivencia, y crecimiento del caballito de mar, Hippocampus ingens en condiciones semi-controladas. Tres machos reproductores silvestres de 14.8, 24.5 y 32.0 g produjeron 1 598, 1 703 y 1 658 jóvenes. La densidad utilizada fue de 12 jóvenes por acuario de 60 l. Se agruparon en 1, 12 y 20 días de nacidos por acuario. La supervivencia fue de 78.5, 38.1 y 41.0 % en 35 días. Se les alimentó con una mezcla de rotíferos B. plicatilis y nauplios de Artemia para después transferirlos a estanques de 100 000 l a una densidad de 50/1 000 l, donde se les alimentó con Artemia adulta durante 60 días más. Crecieron de un promedio de 0.7, 1.5, y 2.7 a 4.5, 5.4 6.7 cm, respectivamente, en 95 días. La temperatura del agua marina utilizada varió de 17 a 23 ºC.We studied fecundity, survival, and growth of the seahorse Hippocampus ingens under semi-controlled conditions. Three wild brood stock mature males of 14.8, 24.5, and 32.0 g released 1 598, 1 703, and 1 658 juveniles. Juvenile stocking densities of 12 were settled in 60-l aquariums in groups of 1, 12, and 20 days old organisms. The rate of survival was 21.5, 61.9, and 59.0 %, respectively, in 35 days. Juveniles were fed a mix diet of rotifers B. plicatilis and Artemia nauplii, then they were transferred to a cement tank of 100 000 l at a density of 50/1 000 l and fed with live adult Artemia for 60 days more. They grew from an average of 0.7, 1.5, and 2.7 to 4.5, 5.4, and 6.7 cm, respectively, in 95 days. The seawater temperature varied from 17 to 23 ºC. Rev. Biol. Trop. 54 (4: 1099-1102. Epub 2006 Dec. 15.
Boehm, J. T.; Waldman, John; Robinson, John D.; Hickerson, Michael J.
Understanding population structure and areas of demographic persistence and transients is critical for effective species management. However, direct observational evidence to address the geographic scale and delineation of ephemeral or persistent populations for many marine fishes is limited. The Lined seahorse (Hippocampus erectus) can be commonly found in three western Atlantic zoogeographic provinces, though inhabitants of the temperate northern Virginia Province are often considered tropical vagrants that only arrive during warm seasons from the southern provinces and perish as temperatures decline. Although genetics can locate regions of historical population persistence and isolation, previous evidence of Virginia Province persistence is only provisional due to limited genetic sampling (i.e., mitochondrial DNA and five nuclear loci). To test alternative hypotheses of historical persistence versus the ephemerality of a northern Virginia Province population we used a RADseq generated dataset consisting of 11,708 single nucleotide polymorphisms (SNP) sampled from individuals collected from the eastern Gulf of Mexico to Long Island, NY. Concordant results from genomic analyses all infer three genetically divergent subpopulations, and strongly support Virginia Province inhabitants as a genetically diverged and a historically persistent ancestral gene pool. These results suggest that individuals that emerge in coastal areas during the warm season can be considered “local” and supports offshore migration during the colder months. This research demonstrates how a large number of genes sampled across a geographical range can capture the diversity of coalescent histories (across loci) while inferring population history. Moreover, these results clearly demonstrate the utility of population genomic data to infer peripheral subpopulation persistence in difficult-to-observe species. PMID:25629166
J T Boehm
Full Text Available Understanding population structure and areas of demographic persistence and transients is critical for effective species management. However, direct observational evidence to address the geographic scale and delineation of ephemeral or persistent populations for many marine fishes is limited. The Lined seahorse (Hippocampus erectus can be commonly found in three western Atlantic zoogeographic provinces, though inhabitants of the temperate northern Virginia Province are often considered tropical vagrants that only arrive during warm seasons from the southern provinces and perish as temperatures decline. Although genetics can locate regions of historical population persistence and isolation, previous evidence of Virginia Province persistence is only provisional due to limited genetic sampling (i.e., mitochondrial DNA and five nuclear loci. To test alternative hypotheses of historical persistence versus the ephemerality of a northern Virginia Province population we used a RADseq generated dataset consisting of 11,708 single nucleotide polymorphisms (SNP sampled from individuals collected from the eastern Gulf of Mexico to Long Island, NY. Concordant results from genomic analyses all infer three genetically divergent subpopulations, and strongly support Virginia Province inhabitants as a genetically diverged and a historically persistent ancestral gene pool. These results suggest that individuals that emerge in coastal areas during the warm season can be considered "local" and supports offshore migration during the colder months. This research demonstrates how a large number of genes sampled across a geographical range can capture the diversity of coalescent histories (across loci while inferring population history. Moreover, these results clearly demonstrate the utility of population genomic data to infer peripheral subpopulation persistence in difficult-to-observe species.
Harasti, D; Martin-Smith, K; Gladstone, W
The aim of this study was to collect data on population dynamics and life history for White's seahorse Hippocampus whitei, a geographically restricted species that is listed as data deficient under the IUCN Red List. Data from H. whitei populations were collected from two regions, Port Stephens (north) and Sydney Harbour (south) in New South Wales, Australia, covering most of the known range of H. whitei, from 2005 to 2010. Over 1000 individuals were tagged using fluorescent elastomer and on subsequent recaptures were re-measured for growth data that were used in a forced Gulland-Holt plot to develop growth parameters for use in a specialized von Bertalanffy growth-function model. Growth parameters for Port Stephens were: females L(∞) = 149·2 mm and K = 2·034 per year and males L(∞) = 147·9 mm and K = 2·520 per year compared with estimates from Sydney Harbour: females L(∞) = 139·8 mm and K = 1·285 per year and males L(∞) = 141·6 mm and K = 1·223 per year. Whilst there was no significant difference in growth between sexes for each region, H. whitei in Port Stephens grew significantly quicker and larger and matured and reproduced at a younger age than those from Sydney Harbour. The life span of H. whitei is at least 5 years in the wild with six individuals recorded reaching this age. Data collected on breeding pairs found that H. whitei displays life-long monogamy with three pairs observed remaining pair bonded over three consecutive breeding years. Baseline population densities were derived for two Port Stephens' sites (0·035 and 0·110 m(-2)) and for Manly in Sydney Harbour (1·050 m(-2)). Even though the life-history parameters of H. whitei suggest it may be reasonably resilient, precaution should be taken in its future management as a result of its limited geographical distribution and increasing pressures from anthropogenic sources on its habitats. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.
Chang, Chia-Hao; Lin, Han-Yang; Jang-Liaw, Nian-Hong; Shao, Kwang-Tsao; Lin, Yeong-Shin; Ho, Hsuan-Ching
The complete mitochondrial genome of the tiger tail seahorse was sequenced using a polymerase chain reaction-based method. The total length of mitochondrial DNA is 16,525 bp and includes 13 protein-coding genes, 2 ribosomal RNA, 22 transfer RNA genes, and a control region. The mitochondrial gene arrangement of the tiger tail seahorse is also matching the one observed in the most vertebrate creatures. Base composition of the genome is A (32.8%), T (29.8%), C (23.0%), and G (14.4%) with an A+T-rich hallmark as that of other vertebrate mitochondrial genomes.
Chang, Chia-Hao; Shao, Kwang-Tsao; Lin, Yeong-Shin; Liao, Yun-Chih
The complete mitochondrial genome of the three-spot seahorse was sequenced using a polymerase chain reaction-based method. The total length of mitochondrial DNA is 16,535 bp and includes 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region. The mitochondrial gene order of the three-spot seahorse also conforms to the distinctive vertebrate mitochondrial gene order. The base composition of the genome is A (32.7%), T (29.3%), C (23.4%), and G (14.6%) with an A + T-rich hallmark as that of other vertebrate mitochondrial genomes.
Shapawi, Rossita; Anyie, Adrian Leslie; Hussien, Muhammad Ali Syed; Zuldin, Wahidatul Husna
Seahorse diversity (genus Hippocampus, Family Syngnathidae), species identification, size composition and sexual dimorphism were studied from November 2012 to March 2013 in selected coastal waters around Kota Kinabalu, Sabah and the local market trade. Six species of seahorses were identified in the study: (1) Hippocampus barbouri, (2) Hippocampus comes, (3) Hippocampus kelloggi, (4) Hippocampus kuda, (5) Hippocampus spinosissimus and (6) Hippocampus trimaculatus. All six species were sold at the local market, and the dried seahorses were obtained mainly by local fishermen using trawl by-catch method and traded as traditional medicine, souvenirs and other uses. Four species were identified by direct samplings in various different habitats of Kota Kinabalu coastal waters: (1) H. barbouri, (2) H. comes, (3) H. kuda, and (4) H. spinosissimus. Based on the results, H. comes was the largest in size among the four fresh/live species found (mean standard length [SL]: 148.25±1.26 mm), whereas H. barbouri was the smallest species (mean SL: 129±7.81 mm). For the dried samples, H. kelloggi was the largest (mean SL: 245.25±14.55 mm) and H. barbouri was the smallest (mean SL: 127.21±10.01 mm). No significant difference (p>0.05) was observed between the lengths of males and females in every seahorse species, and there was no sexual size dimorphism in any of the species. The findings from the study are significant to provide baseline data for the conservation efforts of these unique marine teleost.
Tanu; Deobagkar, D.D.; Khandeparker, R.; Sreepada, R.A.; Sanaye, S.V.; Pawar, H.B.
the snout to suck their prey and swallow whole animals which later on pass through their primitive digestive system consisting of a simple alimentary canal. Seahorses need to feed continuously as they lack a masticatory organ and a true stomach... activities isolated from seahorses (Hippocampus guttulatus). The Journal of Antibiotics 63, 271−274 Barrington E.J.W. (1957) The alimentary canal and digestion. In: The physiology of fishes Vol. 1, (ed. By Brown M.E.), pp. 109−161. Academic press, New York...
Pawar, H.B.; Sanaye, S.V.; Sreepada, R.A.; Harish, V.; Suryavanshi, U.; Tanu; Ansari, Z.A.
155.1±9.8 mm Ht (as in Lourie et al., 1999) and weighing, 11.15±1.68 g wet weight were selected. Seahorses from two different FRP tanks were used to avoid a possible tank effect and were starved 24 h prior to the initiation of anaesthetic...
Dzyuba, Borys; Van Look, Katrien J W; Cliffe, Alex; Koldewey, Heather J; Holt, William V
Seahorses, together with the pipefishes (Family Syngnathidae), are the only vertebrates in which embryonic development takes place within a specialised body compartment, the brood pouch, of the male instead of the female. Embryos develop in close association with the brood pouch epithelium in a manner that bears some resemblance to embryo-placental relationships in mammals. We have explored the hypothesis that parental body size and age should affect offspring postnatal growth and survival if brood pouch quality impacts upon prenatal embryonic nutrition or respiration. Using an aquarium population of the yellow seahorse, Hippocampus kuda, we show here that large parents produce offspring whose initial postnatal growth rates (weeks one to three) were significantly higher than those of the offspring of younger and smaller parents. Whereas 90% of offspring from the larger parents survived for the duration of the study (7 weeks), less that 50% of offspring from smaller parents survived for the same period. For the offspring of large parents, growth rates from individual males were negatively correlated with the number of offspring in the cohort (r=-0.82; P0.9). Observations of embryos within the pouch suggested that when relatively few embryos are present they may attach to functionally advantageous sites and thus gain physiological support during gestation. These results suggest that male body size, and pouch size and function, may influence the future fitness and survival of their offspring.
Full Text Available Seahorse conservation has been performed utilizing various strategies for many decades, and the deeper understanding of genomic information is necessary to more efficiently protect the germplasm resources of seahorse species. However, little genetic information about seahorses currently exists in the public databases. In this study, high-throughput RNA sequencing for two seahorse species, Hippocampus erectus and H. mohnikei, was carried out, and de novo assembly generated 37,506 unigenes for H. erectus and 36,113 unigenes for H. mohnikei. Among them, 17,338 (46.23% unigenes for H. erectus and 17,900 (49.57% for H. mohnikei were successfully annotated based on the information available from the public databases. Through comparing the unigenes of two seahorse species, 7,802 candidate orthologous genes were identified and 5,268 genes among them could be annotated. In addition, gene ontology analysis of two species was similarly performed on biological processes, cellular components, and molecular functions. Twenty-four and twenty-one unigenes in H. erectus and H. mohnikei were annotated in the biosynthesis of unsaturated fatty acids pathways, and both seahorses lacked the Δ12 and Δ15 desaturases. Total of 8,992 and 9,116 SSR loci were obtained from H. erectus and H. mohnikei unigenes, respectively. Dozens of SSR were developed and then applied to assess the population genetic diversity, as well as cross-amplified in a related species, H. trimaculatus. The HO and HE values of the tested populations for H. erectus, H. mohnikei, and H. trimaculatus were medium. These resources would facilitate the conservation of the species through a better understanding of the genomics and comparative genome analysis within the Hippocampus genus.
Lin, Qiang; Luo, Wei; Wan, Shiming; Gao, Zexia
Seahorse conservation has been performed utilizing various strategies for many decades, and the deeper understanding of genomic information is necessary to more efficiently protect the germplasm resources of seahorse species. However, little genetic information about seahorses currently exists in the public databases. In this study, high-throughput RNA sequencing for two seahorse species, Hippocampus erectus and H. mohnikei, was carried out, and de novo assembly generated 37,506 unigenes for H. erectus and 36,113 unigenes for H. mohnikei. Among them, 17,338 (46.23%) unigenes for H. erectus and 17,900 (49.57%) for H. mohnikei were successfully annotated based on the information available from the public databases. Through comparing the unigenes of two seahorse species, 7,802 candidate orthologous genes were identified and 5,268 genes among them could be annotated. In addition, gene ontology analysis of two species was similarly performed on biological processes, cellular components, and molecular functions. Twenty-four and twenty-one unigenes in H. erectus and H. mohnikei were annotated in the biosynthesis of unsaturated fatty acids pathways, and both seahorses lacked the Δ12 and Δ15 desaturases. Total of 8,992 and 9,116 SSR loci were obtained from H. erectus and H. mohnikei unigenes, respectively. Dozens of SSR were developed and then applied to assess the population genetic diversity, as well as cross-amplified in a related species, H. trimaculatus. The HO and HE values of the tested populations for H. erectus, H. mohnikei, and H. trimaculatus were medium. These resources would facilitate the conservation of the species through a better understanding of the genomics and comparative genome analysis within the Hippocampus genus.
González, R; Dinghi, P; Corio, C; Medina, A; Maggioni, M; Storero, L; Gosztonyi, A
A genetic study to support morphometric analyses was used to improve the description and validate the Patagonian seahorse Hippocampus patagonicus (Syngnathidae) on the basis of a large number of specimens collected in the type locality (San Antonio Bay, Patagonia, Argentina). DNA sequence data (from the cytochrome b region of the mitochondrial genome) were used to differentiate this species from its relatives cited for the west Atlantic Ocean. Both phylogenetic and genetic distance analyses supported the hypothesis that H. patagonicus is a species clearly differentiated from others, in agreement with morphometric studies. Hippocampus patagonicus can be distinguished from Hippocampus erectus by the combination of the following morphometric characteristics: (1) in both sexes and all sizes of H. patagonicus, the snout length is always less than the postorbital length, whereas the snout length of H. erectus is not shorter than the postorbital length in the largest specimens; (2) in both sexes of H. patagonicus, the trunk length:total length (LTr :LT ) is lower than in H. erectus (in female H. patagonicus: 0·27-0·39, H. erectus: 0·36-0·40 and in male H. patagonicus: 0·24-0·34, H. erectus: 0·33-0·43) and (3) in both sexes, tail length:total length (LTa :LT ) in H. patagonicus is larger than in H. erectus (0·61-0·78 v. 0·54-0·64). © 2014 The Fisheries Society of the British Isles.
Su, Yuting; Xu, Yongjian
The optimum parameters of extraction for glycoprotein from seahorse were examined and determined by Box-Behnken combined with ultrasonic extraction technology. Column chromatography of glycoprotein was used for further purification. The optimal extraction conditions of seahorse glycoprotein were extracting time 4.3 h, salt concentration 0.08 mol/L, extracting temperature 73°C, raw material, and water ratio 1:6. At the optimal conditions, the yield of saccharide reached to 1.123%, and the yield of protein reached to 5.898%. For purifying the crude glycoprotein, the stage renounces of DEAE-52 column chromatography were done, respectively, with 0.05, 0.1, 0.5 mol/L NaHCO3 solution, and further purification was done with Sephadex G-100 column chromatography. Finally, two pieces of seahorse glycoprotein were obtained by the column chromatography, that is, HG-11 and HG-21. The saccharide content was 56.7975% and 39.479%, the protein content was 30.5475% and 51.747%, respectively. PMID:26288722
Valladares Lago, Sonia
The worldwide decrease of wild seahorse populations is attributed to habitat degradation, incidental captures (by-catch) and overfishing for traditional medicines, curio and aquarium trades. A global conservation concern on the state of wild seahorse populations resulted in the inclusion of all seahorse species in the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species in 1996. Additionally, seahorses were also listed in Appendix II of the C...
Sanaye, S.V.; Pawar, H.B.; Murugan, A.; Sreepada, R.A.; Singh, T.; Ansari, Z.A.
was provided for proper mixing of solution in all over the tank. After 24 hours 80% water changed and replaced with fresh sea water. Care was taken to avoid difference in water quality. Then fresh solution of Diamox® was prepared and added into the tank... (SEM) of single cyst Seahorse aquaculture face unique challenges for health care due to their anatomy and behaviour. Because of its hard and bony-plated body injections are difficult in addition to that; the semi-closed branchial chambers make...
Harasti, D; Martin-Smith, K; Gladstone, W
The aim of this study was to determine and compare habitat preferences for male and female adult and juvenile White's seahorse Hippocampus whitei and assess their movements and site fidelity over 4 years. Data were collected from three sites along 1.5 km of estuarine shoreline in Port Stephens, New South Wales, Australia, from 2006 to 2009 using H. whitei that had been tagged with visible implant fluorescent elastomer. Relative availability of 12 habitats and habitat preferences of H. whitei was determined, based on the habitat that H. whitei used as a holdfast. Hippocampus whitei occurred in nine different habitats; adults preferred sponge and soft coral Dendronephthya australis habitats with no difference between male and female habitat preferences whilst juveniles preferred gorgonian Euplexaura sp. habitat. There was a significant preference by adults for D. australis colonies with height >40 cm and avoidance of colonies <20 cm. Neither adults nor juveniles used sand or the seagrasses Zostera muelleri subsp. capricorni and Halophila ovalis. Hippocampus whitei showed cryptic behaviour with c. 50% of adult sightings cryptic and c. 75% for juveniles with crypsis occurring predominantly in Sargassum sp. for adults and Euplexaura sp. habitat for juveniles. Within sites, females moved significantly longer distances (maximum of 70 m) than males (maximum of 38 m) over 20 months. Strong site fidelity was displayed by H. whitei with males persisting at the same site for up to 56 months and females for 49 months and no H. whitei moved between sites. The longest period that an H. whitei was recorded on the same holdfast was 17 months for a male and 10 months for a female. As this species displays strong site fidelity, specific habitat preferences and has a limited distribution, future management needs to minimize the risk of habitat disturbance as loss of key habitats could have a negative effect on species abundance and distribution. © 2014 The Fisheries Society of the
Woodall, L C; Koldewey, H J; Shaw, P W
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.
Viviane Martins de Oliveira
Full Text Available Seahorses are found all over the world, in tropical and temperate coastal waters. The main aim of this study was to characterize the Hippocampus reidi populations in different depth and hydrodynamism categories in Arraial do Cabo, Rio de Janeiro state. The study was developed through scuba diving, with transects of 20m x 5m in two different depth layers: shallow, between 0 and 5m, and deep, between 5 and 10m. Through visual surveys, individuals were identified according to species, sex, and size (height – HT. The density of H. reidi varied according to depth and hydrodynamism. The highest mean depth was found in the Cabo Frio Island – Ponta do Anequin, as the lowest depth was found in Praia do Forno – Ponta D’água. There is no significant difference in the size of individuals nor in the sex ratio between the depth categories. The sex ratio of H. reidi in the population of Arraial do Cabo was 1:1. The results obtained indicated that the population characteristics are similar between the two depth layers.
André Luiz da Costa Castro
Full Text Available This paper presents the results of the first analysis of the natural diet of Hippocampus reidi, one of the most sought after seahorse species in the international aquarium trade. Its main goals were to investigate food items and prey categories consumed by the species, and to discuss feeding strategy and inter and intra-individual components of niche breadth. Data were gathered from October 2005 to September 2006 at the Mamanguape estuary, State of Paraíba, NE Brazil. Food items from seahorses anaesthetized with clove oil were obtained by using a modified version of the flushing method, and were counted and identified to the lowest possible taxonomic level. Specimens were marked and had their height, sex, life and reproductive stage recorded, and then returned to the same place where they were found for the further assessment of anaesthetization/gut flushing on seahorses. Food items were analyzed using frequency of occurrence, relative abundance, index of preponderance and prey-specific abundance using the points method. The graphic method of Amundsen et al. (1996 was used to interpret the feeding strategy and contribution to niche breadth. Nematodes and crustaceans were the most important items found, the latter item usually being the most commonly found in the gut contents of syngnathids. No significant differences in diet composition were found between reproductive stages, however, a higher proportion of large items were consumed by the larger seahorses. The feeding strategy and niche breadth analysis suggests that H. reidi has a generalist feeding strategy, with high variation between phenotypes. Our results suggest that the anaesthetization-flushing technique has the potential to be a useful tool in seahorse research.
Anderson, Paul A; Petty, Barbara D
Five wild-caught Lined Seahorses Hippocampus erectus from an aquarium system presented with altered buoyancy and distended upper trunks. Radiography of one specimen revealed a reduced air volume in the gas bladder. Pneumocystocentesis revealed a brown exudate of numerous leukocytes, parasite ova, and Gram- and acid-fast-positive bacilli under wet mounts and stains. Necropsies revealed enlarged, friable kidneys and distended gas bladders containing copious purulent exudate, necrotic tissue, and adult digeneans Dictysarca virens. Bacterial isolates from exudate cultures grown on Lowenstein-Jensen medium were identified as Gordonia sp. and Mycobacterium poriferae by high-performance liquid chromatography and 16S ribosomal DNA sequencing. Histopathology demonstrated a histiocytic response in kidney and gas bladder exudate, inflammation of the gas bladder wall, and infection of the gas bladder lumen with parasite ova and acid-fast-positive and Gomori's methenamine silver-positive bacilli. Praziquantel is prescribed for digenean infections but dissolves incompletely in seawater and is toxic to this host. Eradication of intermediate host vectors is a management option. Treatment of Gordonia infection has not been addressed in nonhuman animals, and there is no known effective treatment for Mycobacterium spp. infection in fishes. This is the first case report of digenean infection of the gas bladder in a syngnathid, Gordonia sp. infection in a nonhuman animal, and M. poriferae infection in a fish.
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.
Jo, Eunyoung; Elvitigala, Don Anushka Sandaruwan; Wan, Qiang; Oh, Minyoung; Oh, Chulhong; Lee, Jehee
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.
Full Text Available Estudiamos la fecundidad, supervivencia, y crecimiento del caballito de mar, Hippocampus ingens en condiciones semi-controladas. Tres machos reproductores silvestres de 14.8, 24.5 y 32.0 g produjeron 1 598, 1 703 y 1 658 jóvenes. La densidad utilizada fue de 12 jóvenes por acuario de 60 l. Se agruparon en 1, 12 y 20 días de nacidos por acuario. La supervivencia fue de 78.5, 38.1 y 41.0 % en 35 días. Se les alimentó con una mezcla de rotíferos B. plicatilis y nauplios de Artemia para después transferirlos a estanques de 100 000 l a una densidad de 50/1 000 l, donde se les alimentó con Artemia adulta durante 60 días más. Crecieron de un promedio de 0.7, 1.5, y 2.7 a 4.5, 5.4 6.7 cm, respectivamente, en 95 días. La temperatura del agua marina utilizada varió de 17 a 23 ºC.
Bahr, Angela; Wilson, Anthony B
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
Wilson Anthony B
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
Qin, G.; Li, C.; Lin, Q.
Marine fish species escape from harmful environment by migration. Seahorses, with upright posture and low mobility, could migrate from unfavorable environment by rafting with their prehensile tail. The present study was designed to examine the tolerance of lined seahorse Hippocampus erectus to thermal stress and evaluate the effects of temperature on seahorse migration. The results figured that seahorses' tolerance to thermal stress was time dependent. Acute thermal stress (30°C) increased breathing rate and HSP genes expression significantly, but didn't affect seahorse feeding behavior. Chronic thermal treatment lead to persistent high expression of HSP genes, higher breathing rate, and decreasing feeding, and final higher mortality, suggesting that seahorse cannot adapt to thermal stress by acclimation. No significant negative effects were found in seahorse reproduction in response to chronic thermal stress. Given that seahorses make much slower migration by rafting on sea surface compared to other fishes, we suggest that thermal stress might limit seahorse migration range. and the influence might be magnified by global warming in future.
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.
Godahewa, G I; Perera, N C N; Elvitigala, Don Anushka Sandaruwan; Jayasooriya, R G P T; Kim, Gi-Young; Lee, Jehee
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.
Perera, N C N; Godahewa, G I; Lee, Seongdo; Kim, Myoung-Jin; Hwang, Jee Youn; Kwon, Mun Gyeong; Hwang, Seong Don; Lee, Jehee
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.
Otero-Ferrer, Francisco; Izquierdo, Marisol; Fazeli, Alireza; Holt, William V
The aim of the present study was to investigate the hypothesis that parental periconception nutrition in adult seahorses affects the development and growth of their offspring. We tested the hypothesis that because seahorse embryos develop inside the male's brood pouch, manipulation of the male's diet would affect offspring growth and development independently of the female's diet. Adult males and females were fed separately with either wild-caught crustaceans or commercial aquarium diet for 1 month before conception to influence the periconception environment. Approximately 10000 offspring were obtained from four different treatment groups (Male/Wild or Male/Commercial×Female/Wild or Female/Commercial). Weights, physical dimensions and fatty acid profiles of the newborns were determined. Offspring produced when the males receiving commercial diet were mated with wild-fed females were larger (P<0.05) than those produced by wild-fed males. When both males and females were fed with commercial diet, their offspring were significantly smaller than those from the other treatment groups. When commercial diet-fed females were mated with wild-fed males, the offspring showed distortion of the snout:head length ratio. These results support the view that the preconception diet received by males and females differentially affects embryonic development.
Rosa, Ierecê Ml; Alves, Rômulo Rn; Bonifácio, Kallyne M; Mourão, José S; Osório, Frederico M; Oliveira, Tacyana Pr; Nottingham, Mara C
From a conservationist perspective, seahorses are threatened fishes. Concomitantly, from a socioeconomic perspective, they represent a source of income to many fishing communities in developing countries. An integration between these two views requires, among other things, the recognition that seahorse fishers have knowledge and abilities that can assist the implementation of conservation strategies and of management plans for seahorses and their habitats. This paper documents the knowledge held by Brazilian fishers on the biology and ecology of the longsnout seahorse Hippocampus reidi. Its aims were to explore collaborative approaches to seahorse conservation and management in Brazil; to assess fishers' perception of seahorse biology and ecology, in the context evaluating potential management options; to increase fishers' involvement with seahorse conservation in Brazil. Data were obtained through questionnaires and interviews made during field surveys conducted in fishing villages located in the States of Piauí, Ceará, Paraíba, Maranhão, Pernambuco and Pará. We consider the following aspects as positive for the conservation of seahorses and their habitats in Brazil: fishers were willing to dialogue with researchers; although captures and/or trade of brooding seahorses occurred, most interviewees recognized the importance of reproduction to the maintenance of seahorses in the wild (and therefore of their source of income), and expressed concern over population declines; fishers associated the presence of a ventral pouch with reproduction in seahorses (regardless of them knowing which sex bears the pouch), and this may facilitate the construction of collaborative management options designed to eliminate captures of brooding specimens; fishers recognized microhabitats of importance to the maintenance of seahorse wild populations; fishers who kept seahorses in captivity tended to recognize the condtions as poor, and as being a cause of seahorse mortality.
Oliveira Tacyana PR
Full Text Available Abstract From a conservationist perspective, seahorses are threatened fishes. Concomitantly, from a socioeconomic perspective, they represent a source of income to many fishing communities in developing countries. An integration between these two views requires, among other things, the recognition that seahorse fishers have knowledge and abilities that can assist the implementation of conservation strategies and of management plans for seahorses and their habitats. This paper documents the knowledge held by Brazilian fishers on the biology and ecology of the longsnout seahorse Hippocampus reidi. Its aims were to explore collaborative approaches to seahorse conservation and management in Brazil; to assess fishers' perception of seahorse biology and ecology, in the context evaluating potential management options; to increase fishers' involvement with seahorse conservation in Brazil. Data were obtained through questionnaires and interviews made during field surveys conducted in fishing villages located in the States of Piauí, Ceará, Paraíba, Maranhão, Pernambuco and Pará. We consider the following aspects as positive for the conservation of seahorses and their habitats in Brazil: fishers were willing to dialogue with researchers; although captures and/or trade of brooding seahorses occurred, most interviewees recognized the importance of reproduction to the maintenance of seahorses in the wild (and therefore of their source of income, and expressed concern over population declines; fishers associated the presence of a ventral pouch with reproduction in seahorses (regardless of them knowing which sex bears the pouch, and this may facilitate the construction of collaborative management options designed to eliminate captures of brooding specimens; fishers recognized microhabitats of importance to the maintenance of seahorse wild populations; fishers who kept seahorses in captivity tended to recognize the condtions as poor, and as being a cause of
Saran, A.K.; Sreepada, R.A.; Chakraborty, B.; Fernandes, W.A.; Srivastava, R.; Kuncolienker, D.S.; Gawde, G.
There are many reports of sounds produced by Seahorse (Hippocampus), however, little is known about the mechanism of sound production. Here, we investigate sound produced by the seahorse during feeding. We attempt to try to understand and analyze...
North-East Atlantic), determining the spatial and seasonal abundance, population structure and physical appearance of European short-snouted seahorse Hippocampus hippocampus. Animals were surveyed off Gran Canaria Island in two ...
Tharuka, M D Neranjan; Bathige, S D N K; Lee, Jehee
Glutathione S-transferases (GSTs, EC 184.108.40.206) 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.
Correia, M; Palma, J; Koldewey, H; Andrade, J P
In this study, the spot pattern in Hippocampus guttulatus was analysed using a computer programme algorithm that allowed individual comparison. This methodology was first tested in a controlled environment using 51 adult and 55 juvenile H. guttulatus. Positive matches were obtained in 86·3 and 83·6% of the adults and juveniles, respectively. In a second experiment, monthly surveys were carried out in five selected locations in the Ria Formosa Lagoon, south Portugal, over the course of a year and a total of 980 photographs were analysed. Photographed H. guttulatus were re-sighted one to nine times during the course of the survey period with an overall re-sight record of over 30%. Photo-identification was therefore shown to be a useful tool for non-invasive mark-recapture studies that can be successfully used to survey the population abundance of H. guttulatus aged 6 months or older in consecutive years. This could be of great value when considering the assessment of H. guttulatus populations and understanding changes over time. © 2014 The Fisheries Society of the British Isles.
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.
Oh, Minyoung; Umasuthan, Navaneethaiyer; Elvitigala, Don Anushka Sandaruwan; Wan, Qiang; Jo, Eunyoung; Ko, Jiyeon; Noh, Gyeong Eon; Shin, Sangok; Rho, Sum; Lee, Jehee
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.
Harasti, David; Martin-Smith, Keith; Gladstone, William
Seahorses are iconic charismatic species that are often used to ‘champion’ marine conservation causes around the world. As they are threatened in many countries by over-exploitation and habitat loss, marine protected areas (MPAs) could help with their protection and recovery. MPAs may conserve seahorses through protecting essential habitats and removing fishing pressures. Populations of White's seahorse, Hippocampus whitei, a species endemic to New South Wales, Australia, were monitored monthly from 2006 to 2009 using diver surveys at two sites within a no-take marine protected areas established in 1983, and at two control sites outside the no-take MPA sites. Predators of H. whitei were also identified and monitored. Hippocampus whitei were more abundant at the control sites. Seahorse predators (3 species of fish and 2 species of octopus) were more abundant within the no-take MPA sites. Seahorse and predator abundances were negatively correlated. Substantial variability in the seahorse population at one of the control sites reinforced the importance of long-term monitoring and use of multiple control sites to assess the outcomes of MPAs for seahorses. MPAs should be used cautiously to conserve seahorse populations as there is the risk of a negative impact through increased predator abundance. PMID:25137253
Full Text Available Seahorses are iconic charismatic species that are often used to 'champion' marine conservation causes around the world. As they are threatened in many countries by over-exploitation and habitat loss, marine protected areas (MPAs could help with their protection and recovery. MPAs may conserve seahorses through protecting essential habitats and removing fishing pressures. Populations of White's seahorse, Hippocampus whitei, a species endemic to New South Wales, Australia, were monitored monthly from 2006 to 2009 using diver surveys at two sites within a no-take marine protected areas established in 1983, and at two control sites outside the no-take MPA sites. Predators of H. whitei were also identified and monitored. Hippocampus whitei were more abundant at the control sites. Seahorse predators (3 species of fish and 2 species of octopus were more abundant within the no-take MPA sites. Seahorse and predator abundances were negatively correlated. Substantial variability in the seahorse population at one of the control sites reinforced the importance of long-term monitoring and use of multiple control sites to assess the outcomes of MPAs for seahorses. MPAs should be used cautiously to conserve seahorse populations as there is the risk of a negative impact through increased predator abundance.
Priyathilaka, Thanthrige Thiunuwan; Oh, Minyoung; Bathige, S D N K; De Zoysa, Mahanama; Lee, Jehee
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.
Reijnen, Bastian T; van der Meij, Sancia E T; van Ofwegen, Leen P
An overview of the octocoral and hydrozoan host species of pygmy seahorses is provided based on literature records and recently collected field data for Hippocampus bargibanti, Hippocampus denise and Hippocampus pontohi. Seven new associations are recognized and an overview of the so far documented host species is given. A detailed re-examination of octocoral type material and a review of the taxonomic history of the alcyonacean genera Annella (Subergorgiidae) and Muricella (Acanthogorgiidae) are included as baseline for future revisions. The host specificity and colour morphs of pygmy seahorses are discussed, as well as the reliability of (previous) identifications and conservation issues.
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.
Perera, N C N; Godahewa, G I; Lee, Jehee
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
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.
Godahewa, G I; Perera, N C N; Lee, Jehee
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.
Lin, Qiang; Fan, Shaohua; Zhang, Yanhong; Xu, Meng; Zhang, Huixian; Yang, Yulan; Lee, Alison P; Woltering, Joost M; Ravi, Vydianathan; Gunter, Helen M; Luo, Wei; Gao, Zexia; Lim, Zhi Wei; Qin, Geng; Schneider, Ralf F; Wang, Xin; Xiong, Peiwen; Li, Gang; Wang, Kai; Min, Jiumeng; Zhang, Chi; Qiu, Ying; Bai, Jie; He, Weiming; Bian, Chao; Zhang, Xinhui; Shan, Dai; Qu, Hongyue; Sun, Ying; Gao, Qiang; Huang, Liangmin; Shi, Qiong; Meyer, Axel; Venkatesh, Byrappa
Seahorses have a specialized morphology that includes a toothless tubular mouth, a body covered with bony plates, a male brood pouch, and the absence of caudal and pelvic fins. Here we report the sequencing and de novo assembly of the genome of the tiger tail seahorse, Hippocampus comes. Comparative genomic analysis identifies higher protein and nucleotide evolutionary rates in H. comes compared with other teleost fish genomes. We identified an astacin metalloprotease gene family that has undergone expansion and is highly expressed in the male brood pouch. We also find that the H. comes genome lacks enamel matrix protein-coding proline/glutamine-rich secretory calcium-binding phosphoprotein genes, which might have led to the loss of mineralized teeth. tbx4, a regulator of hindlimb development, is also not found in H. comes genome. Knockout of tbx4 in zebrafish showed a 'pelvic fin-loss' phenotype similar to that of seahorses.
Rose, Emily; Masonjones, Heather D; Jones, Adam G
Isolated populations provide special opportunities to study local adaptation and incipient speciation. In some cases, however, morphological evolution can obscure the taxonomic status of recently founded populations. Here, we use molecular markers to show that an anchialine-lake-restricted population of seahorses, originally identified as Hippocampus reidi, appears on the basis of DNA data to be Hippocampus erectus We collected seahorses from Sweetings Pond, on Eleuthera Island, Bahamas, during the summer of 2014. We measured morphological traits and sequenced 2 genes, cytochrome b and ribosomal protein S7, from 19 seahorses in our sample. On the basis of morphology, Sweetings Pond seahorses could not be assigned definitively to either of the 2 species of seahorse, H. reidi and H. erectus, that occur in marine waters surrounding the Bahamas. However, our DNA-based phylogenetic analysis showed that the Sweetings Pond fish were firmly nested within the H. erectus clade with a Bayesian posterior probability greater than 0.99. Thus, Sweetings Pond seahorses most recently shared a common ancestor with H. erectus populations from the Western Atlantic. Interestingly, the seahorses from Sweetings Pond differ morphologically from other marine populations of H. erectus in having a more even torso to tail length ratio. The substantial habitat differences between Sweetings Pond and the surrounding coastal habitat make Sweetings Pond seahorses particularly interesting from the perspectives of conservation, local adaptation, and incipient speciation. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: email@example.com.
Marcus, J E; Samoilys, M A; Meeuwig, J J; Villongco, Z A D; Vincent, A C J
Benthic status of 28 near-shore, artisanal, coral reef fishing grounds in the central Philippines was assessed (2000-2002) together with surveys of the seahorse, Hippocampus comes. Our measures of benthic quality and seahorse densities reveal some of the most degraded coral reefs in the world. Abiotic structure dominated the fishing grounds: 69% of the benthos comprised rubble (32%), sand/silt (28%) and dead coral (9%). Predominant biotic structure included live coral (12%) and Sargassum (11%). Rubble cover increased with increasing distance from municipal enforcement centers and coincided with substantial blast fishing in this region of the Philippines. Over 2 years, we measured a significant decrease in benthic 'heterogeneity' and a 16% increase in rubble cover. Poor benthic quality was concomitant with extremely low seahorse densities (524 fish per km(2)). Spatial management, such as marine reserves, may help to minimize habitat damage and to rebuild depleted populations of seahorses and other reef fauna.
Anthropogenic development, especially the transformation of natural habitats to artificial, is a growing concern within estuaries and coastal areas worldwide. Thesen Islands marina, an artificial water body, added 25 ha of new estuarine habitat to the Knysna Estuary in South Africa, home to the Knysna seahorse. This study aimed to answer: (I) Can an artificial water body provide suitable habitat for an endangered seahorse species? And if so (II) what characteristics of this new habitat are important in terms of seahorse utilization? Four major habitat types were identified within the marina canals: (I) artificial reno mattress (wire baskets filled with rocks); (II) Codium tenue beds; (III) mixed vegetation on sediment; and (IV) barren canal floor. Seahorses were found throughout the marina system with significantly higher densities within the reno mattress habitat. The artificial water body, therefore, has provided suitable habitat for Hippocampus capensis, a noteworthy finding in the current environment of coastal development and the increasing shift from natural to artificial.
Correia, M; Caldwell, I R; Koldewey, H J; Andrade, J P; Palma, J
Comparisons of three sets of surveys in the Ria Formosa Lagoon, Portugal, over a 13 year period (2001-2002, 2008-2009 and 2010-2013) revealed significant population fluctuations in at least one of the two seahorse (Hippocampinae) species living there, and that those fluctuations were potentially associated with habitat changes in the lagoon. After a significant decline between the first two survey periods (2001-2002 v. 2008-2009), long-snouted seahorse Hippocampus guttulatus populations increased significantly between 2008-2009 surveys and new 2010-2013 surveys. There were no significant differences in H. guttulatus populations between the 2001-2002 and 2010-2013 surveys. In contrast, there were no significant differences in short-snouted seahorse Hippocampus hippocampus densities among the 16 sites surveyed throughout the three sampling periods, although the ability to detect any change was hampered by the low densities of this species in all time periods. Fluctuations in H. guttulatus densities were positively correlated with the percentage of holdfast coverage, but with none of the other environmental variables tested. These results highlight the importance of holdfast availability in maintaining stable seahorse populations. While population fluctuations are certainly more promising than a consistent downward decline, such extreme fluctuations observed for seahorses in the Ria Formosa Lagoon could still leave these two species vulnerable to any additional stressors, particularly during low density periods. © 2015 The Fisheries Society of the British Isles.
Teske, PR; Hamilton, H; Palsboll, PJ; Choo, CK; Gabr, H; Lourie, SA; Santos, M; Sreepada, A; Cherry, MI; Matthee, CA
Mitochondrial control region (mtDNA CR) diversity within and among 6 seahorse populations associated with the Indo-Pacific Hippocampus kuda complex (H. kuda from India, Malaysia, Indonesia and the Philippines, H. fuscus from the Red Sea and H. capensis from South Africa) was compared to determine
Lawson, J M; Foster, S J; Lim, A C O; Chong, V C; Vincent, A C J
Life-history variables for three incidentally captured species of seahorse (Kellogg's seahorse Hippocampus kelloggi, the hedgehog seahorse Hippocampus spinosissimus and the three-spot seahorse Hippocampus trimaculatus) were established using specimens obtained from 33 fisheries landing sites in Peninsular Malaysia. When samples were pooled by species across the peninsula, sex ratios were not significantly different from unity, and height and mass relationships were significant for all species. For two of these species, height at physical maturity (HM ) was smaller than the height at which reproductive activity (HR ) commenced: H. spinosissimus (HM = 99·6 mm, HR = 123·2 mm) and H. trimaculatus (HM = 90·5 mm, HR = 121·8 mm). For H. kelloggi, HM could not be estimated as all individuals were physically mature, while HR = 167·4 mm. It appears that all three Hippocampus spp. were, on average, caught before reproducing; height at 50% capture (HC ) was ≥HM but ≤HR . The results from this study probe the effectiveness of assessment techniques for data-poor fisheries that rely heavily on estimates of length at maturity, especially if maturity is poorly defined. Findings also question the sustainability of H. trimaculatus catches in the south-west region of Peninsular Malaysia, where landed specimens had a notably smaller mean height (86·2 mm) and markedly skewed sex ratio (6% males) compared with samples from the south-east and north-west of the peninsula. © 2014 The Fisheries Society of the British Isles.
Zhang, Yan-Hong; Qin, Geng; Wang, Xin; Lin, Qiang
A new species of seahorse, Hippocampus casscsio sp. nov. was collected over shallow seagrass beds in Beibu Bay, China. This species is diagnosed from all other seahorse species by morphological characters, including the lower number of tail rings (35); 15 pectoral-fin rays; 16 dorsal-fin rays; a rounded nuchal plate without a raised coronet; a snout length 30% head length; two cheek spines and a dark brown coloration. In addition, molecular analysis showed all individuals of the new species clustering together suggesting a monophyletic lineage. This combined analysis supports the distinctness of H. casscsio sp. nov. as a new species, which is described herein.
Hou, Feixia; Wen, Longlian; Peng, Cheng; Guo, Jinlin
Seahorse documented in Chinese pharmacopeia possess important medicinal efficacy and are used as an ingredient in traditional Chinese medicines. The growing international trade threatens the species. DNA barcoding holds a great application potentiality in wildlife conservation and might prevent the illegal trade of threatened species. The COI gene was used to identify seahorse, and nine Hippocampus species were found in the three large traditional Chinese medicines markets of China. All inter-specific genetic variations were larger than 2%. Mean genetic distances between species were 17-fold larger than those within the species. Phylogenetic tree showed that each species clustered in the appropriate branch. All results demonstrated that COI-based barcoding technique could be used to identify seahorse species and played a major role in monitoring the seahorse trade.
Woodall, Lucy C; Otero-Ferrer, Francisco; Correia, Miguel; Curtis, Janelle M R; Garrick-Maidment, Neil; Shaw, Paul W; Koldewey, Heather J
Accurate taxonomy, population demography, and habitat descriptors inform species threat assessments and the design of effective conservation measures. Here we combine published studies with new genetic, morphological and habitat data that were collected from seahorse populations located along the European and North African coastlines to help inform management decisions for European seahorses. This study confirms the presence of only two native seahorse species ( Hippocampus guttulatus and H. hippocampus ) across Europe, with sporadic occurrence of non-native seahorse species in European waters. For the two native species, our findings demonstrate that highly variable morphological characteristics, such as size and presence or number of cirri, are unreliable for distinguishing species. Both species exhibit sex dimorphism with females being significantly larger. Across its range, H. guttulatus were larger and found at higher densities in cooler waters, and individuals in the Black Sea were significantly smaller than in other populations. H. hippocampus were significantly larger in Senegal. Hippocampus guttulatus tends to have higher density populations than H. hippocampus when they occur sympatrically. Although these species are often associated with seagrass beds, data show both species inhabit a wide variety of shallow habitats and use a mixture of holdfasts. We suggest an international mosaic of protected areas focused on multiple habitat types as the first step to successful assessment, monitoring and conservation management of these Data Deficient species.
Van Wassenbergh, Sam; Roos, Gert; Genbrugge, Annelies; Leysen, Heleen; Aerts, Peter; Adriaens, Dominique; Herrel, Anthony
Ongoing anatomical development typically results in a gradual maturation of the feeding movements from larval to adult fishes. Adult seahorses are known to capture prey by rotating their long-snouted head extremely quickly towards prey, followed by powerful suction. This type of suction is powered by elastic recoil and requires very precise coordination of the movements of the associated feeding structures, making it an all-or-none phenomenon. Here, we show that newborn Hippocampus reidi are able to successfully feed using an extremely rapid and powerful snout rotation combined with a high-volume suction, surpassing that observed in adult seahorses. An inverse dynamic analysis shows that an elastic recoil mechanism is also used to power head rotation in newborn H. reidi. This illustrates how extreme levels of performance in highly complex musculoskeletal systems can be present at birth given a delayed birth and rapid development of functionally important structures. The fact that the head skeleton of newborn seahorses is still largely cartilaginous may not be problematic because the hydrodynamic stress on the rotating snout appeared considerably lower than in adult syngnathids. PMID:19324657
Ternes, Maria L. F.; Gerhardinger, Leopoldo C.; Schiavetti, Alexandre
Background Seahorses are endangered teleost fishes under increasing human pressures worldwide. In Brazil, marine conservationists and policy-makers are thus often skeptical about the viability of sustainable human-seahorse interactions. This study focuses on local ecological knowledge on seahorses and the implications of their non-lethal touristic use by a coastal community in northeastern Brazil. Community-based seahorse-watching activities have been carried out in Maraca?pe village since 19...
Ternes, Maria L F; Gerhardinger, Leopoldo C; Schiavetti, Alexandre
Seahorses are endangered teleost fishes under increasing human pressures worldwide. In Brazil, marine conservationists and policy-makers are thus often skeptical about the viability of sustainable human-seahorse interactions. This study focuses on local ecological knowledge on seahorses and the implications of their non-lethal touristic use by a coastal community in northeastern Brazil. Community-based seahorse-watching activities have been carried out in Maracaípe village since 1999, but remained uninvestigated until the present study. Our goal is to provide ethnoecological understanding on this non-extractive use to support seahorse conservation and management. We interviewed 32 informants through semi-structured questionnaires to assess their socioeconomic profile, their knowledge on seahorse natural history traits, human uses, threats and abundance trends. Seahorse-watching has high socioeconomic relevance, being the primary income source for all respondents. Interviewees elicited a body of knowledge on seahorse biology largely consistent with up-to-date research literature. Most informants (65.5 %) perceived no change in seahorse abundance. Their empirical knowledge often surpassed scientific reports, i.e. through remarks on trophic ecology; reproductive aspects, such as, behavior and breeding season; spatial and temporal distribution, suggesting seahorse migration related to environmental parameters. Seahorse-watching operators were aware of seahorse biological and ecological aspects. Despite the gaps remaining on biological data about certain seahorse traits, the respondents provided reliable information on all questions, adding ethnoecological remarks not yet assessed by conventional scientific surveys. We provide novel ethnobiological insight on non-extractive modes of human-seahorse interaction, eliciting environmental policies to integrate seahorse conservation with local ecological knowledge and innovative ideas for seahorse sustainable use. Our study
Faleiro, Filipa; Baptista, Miguel; Santos, Catarina; Aurélio, Maria L; Pimentel, Marta; Pegado, Maria Rita; Paula, José Ricardo; Calado, Ricardo; Repolho, Tiago; Rosa, Rui
Seahorses are currently facing great challenges in the wild, including habitat degradation and overexploitation, and how they will endure additional stress from rapid climate change has yet to be determined. Unlike most fishes, the poor swimming skills of seahorses, along with the ecological and biological constraints of their unique lifestyle, place great weight on their physiological ability to cope with climate changes. In the present study, we evaluate the effects of ocean warming (+4°C) and acidification (ΔpH = -0.5 units) on the physiological and behavioural ecology of adult temperate seahorses, Hippocampus guttulatus. Adult seahorses were found to be relatively well prepared to face future changes in ocean temperature, but not the combined effect of warming and acidification. Seahorse metabolism increased normally with warming, and behavioural and feeding responses were not significantly affected. However, during hypercapnia the seahorses exhibited signs of lethargy (i.e. reduced activity levels) combined with a reduction of feeding and ventilation rates. Nonetheless, metabolic rates were not significantly affected. Future ocean changes, particularly ocean acidification, may further threaten seahorse conservation, turning these charismatic fishes into important flagship species for global climate change issues.
Xu, Dong-Hui; Wang, Li-Hong; Mei, Xue-Ting; Li, Bing-Ji; Lv, Jun-Li; Xu, Shi-Bo
This study investigated the effects of seahorse (Hippocampus spp.) extracts in a rat model of benign prostatic hyperplasia (BPH) and mouse model of oligospermatism. Compared to the sham operated group, castration and testosterone induced BPH, indicated by increased penile erection latency; decreased penis nitric oxide synthase (NOS) activity; reduced serum acid phosphatase (ACP) activity; increased prostate index; and epithelial thickening, increased glandular perimeter, increased proliferating cell nuclear antigen (PCNA) index and upregulation of basic fibroblast growth factor (bFGF) in the prostate. Seahorse extracts significantly ameliorated the histopathological changes associated with BPH, reduced the latency of penile erection and increased penile NOS activity. Administration of seahorse extracts also reversed epididymal sperm viability and motility in mice treated with cyclophosphamide (CP). Seahorse extracts have potential as a candidate marine drug for treating BPH without inducing the side effects of erectile dysfunction (ED) or oligospermatism associated with the BPH drug finasteride. Copyright © 2014 Elsevier B.V. All rights reserved.
Leung, Dilys T H; Chu, Simon
The Seahorse XFp Analyzer is a powerful tool for the assessment of various parameters of cellular respiration. Here we describe the process of the Seahorse Cell Phenotype Test using the Seahorse XFp Analyzer to characterize the metabolic phenotype of live cells. The Seahorse XFp Analyzer can also be coupled with other assays to measure cellular energetics. Given that mitochondrial dysfunction is implicated in preeclampsia, the Seahorse XFp Analyzer will serve as a useful tool for the understanding of pathological metabolism in this disorder.
Whittington, Camilla M; Griffith, Oliver W; Qi, Weihong; Thompson, Michael B; Wilson, Anthony B
Viviparity (live birth) has evolved more than 150 times in vertebrates, and represents an excellent model system for studying the evolution of complex traits. There are at least 23 independent origins of viviparity in fishes, with syngnathid fishes (seahorses and pipefish) unique in exhibiting male pregnancy. Male seahorses and pipefish have evolved specialized brooding pouches that provide protection, gas exchange, osmoregulation, and limited nutrient provisioning to developing embryos. Pouch structures differ widely across the Syngnathidae, offering an ideal opportunity to study the evolution of reproductive complexity. However, the physiological and genetic changes facilitating male pregnancy are largely unknown. We used transcriptome profiling to examine pouch gene expression at successive gestational stages in a syngnathid with the most complex brood pouch morphology, the seahorse Hippocampus abdominalis. Using a unique time-calibrated RNA-seq data set including brood pouch at key stages of embryonic development, we identified transcriptional changes associated with brood pouch remodeling, nutrient and waste transport, gas exchange, osmoregulation, and immunological protection of developing embryos at conception, development and parturition. Key seahorse transcripts share homology with genes of reproductive function in pregnant mammals, reptiles, and other live-bearing fish, suggesting a common toolkit of genes regulating pregnancy in divergent evolutionary lineages. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Kvarnemo, Charlotta; Moore, Glenn I; Jones, Adam G
Studies of sexual selection in monogamous species have hitherto focused on sexual selection among males. Here, we provide empirical documentation that sexual selection can also act strongly on females in a natural population with a monogamous mating system. In our field-based genetic study of the monogamous Western Australian seahorse, Hippocampus subelongatus, sexual selection differentials and gradients show that females are under stronger sexual selection than males: mated females are larger than unmated ones, whereas mated and unmated males do not differ in size. In addition, the opportunity for sexual selection (variance in mating success divided by its mean squared) for females is almost three times that for males. These results, which seem to be generated by a combination of a male preference for larger females and a female-biased adult sex ratio, indicate that substantial sexual selection on females is a potentially important but under-appreciated evolutionary phenomenon in monogamous species.
Gemmell, Brad; Sheng, Jian; Buskey, Ed
Copepods are an important planktonic food source for most of the world's fish species. This high predation pressure has led copepods to evolve an extremely effective escape response, with reaction times to hydrodynamic disturbances of less than 4 ms and escape speeds of over 500 body lengths per second. Using 3D high speed digital holographic cinematography (up to 2000 frames per second) we elucidate the role of entrainment flow fields generated by a natural visual predator, the dwarf seahorse (Hippocampus zosterae) during attacks on its prey, Acartia tonsa. Using phytoplankton as a tracer, we recorded and reconstructed 3D flow fields around the head of the seahorse and its prey during both successful and unsuccessful attacks to better understand how some attacks lead to capture with little or no detection from the copepod while others result in failed attacks. Attacks start with a slow approach to minimize the hydro-mechanical disturbance which is used by copepods to detect the approach of a potential predator. Successful attacks result in the seahorse using its pipette-like mouth to create suction faster than the copepod's response latency. As these characteristic scales of entrainment increase, a successful escape becomes more likely.
Adam, Kindi; Fitria, Laksmindra; Sarto, Mulyati
Seahorse (Hippocampus kuda) is known to have a high concentration of iron, taurin and progesteron as testosteron precursor. Seahorse extract can increase the production of testosterone hormone of mice. On the erythrocytes development, kidney is stimulated to release erythropoietin hormone in case of hypoxia and also related with testosterone production. Erythropoietin control erythrocytes development and increase hemoglobin synthesis. The objective of experiment was to study the effect of sea...
Kindi Adam; Laksmindra Fitria; Mulyati Sarto
Seahorse (Hippocampus kuda) is known to have a high concentration of iron, taurin and progesteron as testosteron precursor. Seahorse extract can increase the production of testosterone hormone of mice. On the erythrocytes development, kidney is stimulated to release erythropoietin hormone in case of hypoxia and also related with testosterone production. Erythropoietin control erythrocytes development and increase hemoglobin synthesis. The objective of experiment was to study the effect of sea...
We will first present unique dendritic "seahorse" patterns observed when we study structural features in functional C60-TCNQ complex thin films, and their formation mechanism. Then we report a new process for ultrahigh density, erasable data storage, based on the molecular electrical bistability of an organic charge transfer complex, 3-nitrobenzal malononitrile and 1,4-phenylenediamine (NBMN-pDA). Switched by a voltage pulse from a scanning tunneling microscope (STM), we demonstrate a data density exceeding 1013 bits/cm2. The experiment results and theoretical ab initio calculations show the writing and erasing mechanism to be a conductance transition of the organic compound due to a structural change from crystalline to noncrystalline. The ultimate bit density appears limited only by the size of the organic complex, less than 1 nm in our case, corresponding to 1014 bits/cm2.
Faleiro, Filipa; Narciso, Luís
In captivity, husbandry conditions are distinct from those experienced by fish in the wild and may have a significant effect on reproductive success. This study evaluates the effect of supportive breeding (i.e., breeding animals in captivity using wild parents) on some quantitative and qualitative aspects of the reproductive success of the long-snouted seahorse, Hippocampus guttulatus. Wild and captive broods were compared in terms of juvenile number, size, condition and fatty acid profile at birth. Reproductive investment and breeding success of H. guttulatus decreased considerably in captivity. Juveniles from captive broods were fewer in number, smaller, generally thinner and with lower fatty acid contents (per juvenile) than those from wild broods, although their fatty acid composition (μg mg- 1 DW or %TFA) was not significantly affected. Although not greatly encouraging, the poor reproductive performance of captive seahorses should not, however, efface the potential of supportive breeding as a tool for seahorse conservation. Enhanced conditions and long-term breeding in captivity will allow to improve the reproductive success of the species and the quality of the fingerlings.
Porter, Michael M; Adriaens, Dominique; Hatton, Ross L; Meyers, Marc A; McKittrick, Joanna
Whereas the predominant shapes of most animal tails are cylindrical, seahorse tails are square prisms. Seahorses use their tails as flexible grasping appendages, in spite of a rigid bony armor that fully encases their bodies. We explore the mechanics of two three-dimensional-printed models that mimic either the natural (square prism) or hypothetical (cylindrical) architecture of a seahorse tail to uncover whether or not the square geometry provides any functional advantages. Our results show that the square prism is more resilient when crushed and provides a mechanism for preserving articulatory organization upon extensive bending and twisting, as compared with its cylindrical counterpart. Thus, the square architecture is better than the circular one in the context of two integrated functions: grasping ability and crushing resistance. Copyright © 2015, American Association for the Advancement of Science.
Roos, Gert; Leysen, Heleen; Van Wassenbergh, Sam; Herrel, Anthony; Jacobs, Patric; Dierick, Manuel; Aerts, Peter; Adriaens, Dominique
Syngnathid fishes (seahorses, pipefish, and sea dragons) possess a highly modified cranium characterized by a long and tubular snout with minute jaws at its end. Previous studies indicated that these species are extremely fast suction feeders with their feeding strike characterized by a rapid elevation of the head accompanied by rotation of the hyoid. A planar four-bar model is proposed to explain the coupled motion of the neurocranium and the hyoid. Because neurocranial elevation as well as hyoid rotation are crucial for the feeding mechanism in previously studied Syngnathidae, a detailed evaluation of this model is needed. In this study, we present kinematic data of the feeding strike in the seahorse Hippocampus reidi. We combined these data with a detailed morphological analysis of the important linkages and joints involved in rotation of the neurocranium and the hyoid, and we compared the kinematic measurements with output of a theoretical four-bar model. The kinematic analysis shows that neurocranial rotation never preceded hyoid rotation, thus indicating that hyoid rotation triggers the explosive feeding strike. Our data suggest that while neurocranium and hyoid initially (first 1.5 ms) behave as predicted by the four-bar model, eventually, the hyoid rotation is underestimated by the model. Shortening, or a posterior displacement of the sternohyoid muscle (of which the posterior end is confluent with the hypaxial muscles in H. reidi), probably explains the discrepancy between the model and our kinematic measurements. As a result, while four-bar modeling indicates a clear coupling between hyoid rotation and neurocranial elevation, the detailed morphological determination of the linkages and joints of this four-bar model remain crucial in order to fully understand this mechanism in seahorse feeding.
Bir, Shyamal C; Ambekar, Sudheer; Kukreja, Sunil; Nanda, Anil
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.
Harasti, D; Gladstone, W
The effect of flash photography on seahorse species has never been tested. An experiment was established to test the effect of flash photography and the handling of Hippocampus whitei, a medium-sized seahorse species endemic to Australia, on their behavioural responses, movements and site persistence. A total of 24 H. whitei were utilized in the experiment with eight in each of the three treatments (flash photography, handling and control). The effect of underwater flash photography on H. whitei movements was not significant; however, the effect of handling H. whitei to take a photograph had a significant effect on their short-term behavioural responses to the photographer. Kaplan-Meier log-rank test revealed that there was no significant difference in site persistence of H. whitei from each of the three treatments and that flash photography had no long-term effects on their site persistence. It is concluded that the use of flash photography by divers is a safe and viable technique with H. whitei, particularly if photographs can be used for individual identification purposes. © 2013 The Fisheries Society of the British Isles.
Oct 29, 2012 ... Project Seahorse evolves into major marine protector ... local people, have greatly improved the prospects of survival for threatened species. ... “We tackle issues on any political level or geographical scale, according to what ...
Porter, Michael M; Novitskaya, Ekaterina; Castro-Ceseña, Ana Bertha; Meyers, Marc A; McKittrick, Joanna
Multifunctional materials and devices found in nature serve as inspiration for advanced synthetic materials, structures and robotics. Here, we elucidate the architecture and unusual deformation mechanisms of seahorse tails that provide prehension as well as protection against predators. The seahorse tail is composed of subdermal bony plates arranged in articulating ring-like segments that overlap for controlled ventral bending and twisting. The bony plates are highly deformable materials designed to slide past one another and buckle when compressed. This complex plate and segment motion, along with the unique hardness distribution and structural hierarchy of each plate, provide seahorses with joint flexibility while shielding them against impact and crushing. Mimicking seahorse armor may lead to novel bio-inspired technologies, such as flexible armor, fracture-resistant structures or prehensile robotics. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Full Text Available Survival during first months after birth is one of the bottlenecks for consolidating the seahorse farming industry. In this work, Artemia metanauplii enriched with two highly unsaturated fatty acids (HUFA rich commercial emulsions with different docosahexaenoic acid (DHA levels (63% and 14% of total lipids, a vegetable oil with no DHA, and non-enriched Artemia as control, were used to feed 5-day-old juvenile Hippocampus erectus for 60 days. Enriched Artemia had similar levels of DHA (13% and 9%, despite great differences of DHA in the emulsions, with traces of DHA in non-enriched and vegetable oil enriched Artemia. More than 20% of DHA was found in 24 h starved juveniles fed both DHA-enriched treatments, similar to values in newly born juveniles, but those fed vegetable oil enriched Artemia or non-enriched Artemia had 5% of DHA. Total lipid and protein levels were similar in juveniles from the four treatments. The n-3/n-6 ratio was almost four-fold higher in seahorses fed DHA-enriched treatments compared to juveniles fed the non-enriched treatments. Survival of seahorses only partially reflected the DHA levels: it was lower in the vegetable oil treatment, similar in the seahorses fed Artemia with higher DHA and in the control treatment, and higher in seahorses fed the HUFA-enriched Artemia with lower DHA levels, although growth was similar in the two DHA-enriched Artemia treatments. Juvenile H. erectus seahorses perform better when they have at least 20% of DHA in their tissues, and these levels can be attained with no more than 14% of DHA in emulsions, eliminating the need for more expensive emulsions with higher DHA levels.
Mauro Alves da Cunha
Full Text Available The aim of this study was to identify the times of anesthetic induction and recovery in slender seahorses (Hippocampus reidi that were exposed to the essential oil of Lippia alba (EO, as well as the efficacy of EO as a stress-reducing agent in the transport of this species. Slender seahorses were placed in 1-L aquaria containing different concentrations of EO (0, 10, 20, 50, 150, 300 and 450 µL L-1, and after induction, fish were transferred to aquaria that were free of anesthetic to evaluate their recovery time. In an additional experiment, slender seahorses were transported in plastic bags with 15 µL L-1 of EO for 4 or 24 h. The increased concentration of EO proportionally decreased the time required for the induction of anesthesia. EO treatment (15 µL L-1 inhibited the increase in blood glucose levels that was provoked by transportation for 4 or 24 h. Transportation for 24 h also decreased the number of lymphocytes and increased the neutrophil count, and these effects were avoided with the addition of EO to the water. These results demonstrate that EO was effective as an anesthetic at concentrations of 10-20 µL L-1 for slight sedation and transport and at 150 µL L-1 for deep anesthesia in the slender seahorse.
Full Text Available Seagrass meadows of the Venice lagoon (Northern Adriatic Sea, Italy are spatially heterogeneous systems, with attributes such as degree of coverage and plant assemblages varying along multiple environmental gradients. They play a particularly relevant role in conservation of fish diversity, since they provide vital habitats for pipefish and seahorse species (family Syngnathidae. Aim of the study was to investigate the diversity of syngnathid assemblages in the Venice lagoon and link species distributions to habitat characteristics, in order to evaluate the importance of seagrass meadows of the lagoon for the conservation of these species. The analyses of this work are based on eight years of fish data collected between 2001 and 2014 in 186 shallow water sites across the entire lagoon. Water parameters, presence of macroalgae, seagrass presence and coverage, as well as meadows species composition, were considered as predictors in a modelling framework, to explain the distribution of each species. Overall, two species of seahorses and seven species of pipefishes including the Adriatic endemism Syngnathus taenionotus were found. Three species (S. abaster, S. typhle and Nerophis ophidion were the most abundant, together accounting for 98% of total individuals caught. Both seagrass presence and its coverage resulted significant predictors, with densities of S. abaster, S. typhle, N. ophidion and Hippocampus guttulatus being positively associated with higher percentages of seagrass cover. In addition, some evidences suggested a different functionality of different meadow types in supporting both S. typhle and N. ophidion. The study highlighted the role of Venice lagoon as biodiversity hotspot for syngnathids, since it supports nine out of the 10 species known in the Mediterranean (with only S. phlegon being absent. Results also suggested the importance of habitat management, which should aim at compensating for seagrass habitat loss and therefore
Full Text Available An overview of the octocoral and hydrozoa host species of pygmy seahorses is provided, based on recently collected data for H. bargibanti, H. denise and H. pontohi and literature records. Seven new interspecific host-species associations are recognized, and an overview of the so far documented number of host species is given. Detailed re-examination of octocoral type material and a review of the taxonomic history are included, as a baseline for further studies. The host-specificity and colour morphs of pygmy seahorses are discussed, as well as the validity of (previous identifications and conservations issues.
Williams, Susan L.; Janetski, Noel; Abbott, Jessica; Blankenhorn, Sven; Cheng, Brian; Crafton, R. Eliot; Hameed, Sarah O.; Rapi, Saipul; Trockel, Dale
Ornamental marine species (`OMS') provide valuable income for developing nations in the Indo-Pacific Coral Triangle, from which most of the specimens are exported. OMS culture can help diversify livelihoods in the region, in support of management and conservation efforts to reduce destructive fishing and collection practices that threaten coral reef and seagrass ecosystems. Adoption of OMS culture depends on demonstrating its success as a livelihood, yet few studies of OMS culture exist in the region. We present a case study of a land-based culture project for an endangered seahorse ( Hippocampus barbouri) in the Spermonde Islands, Sulawesi, Indonesia. The business model demonstrated that culturing can increase family income by seven times. A Strengths Weaknesses Opportunities Threats (SWOT) analysis indicated good collaboration among diverse stakeholders and opportunities for culturing non-endangered species and for offshoot projects, but complicated permitting was an issue as were threats of market flooding and production declines. The OMS international market is strong, Indonesian exporters expressed great interest in cultured product, and Indonesia is the largest exporting country for H. barbouri. Yet, a comparison of Indonesia ornamental marine fish exports to fish abundance in a single local market indicated that OMS culture cannot replace fishing livelihoods. Nevertheless, seahorse and other OMS culture can play a role in management and conservation by supplementing and diversifying the fishing and collecting livelihoods in the developing nations that provide the majority of the global OMS.
Gemmell, Brad; Buskey, Edward; Sheng, Jian
Copepods are an important planktonic food source for fish species. High predation has led to the development of effective escape responses with short reaction times (less than 2 ms), maximum escape velocities of over 500 body lengths per second and shear sensitivity as low as 1.5s-1. Using high speed digital holography (2 kfps), we measure 3-D distributions of velocity generated by a dwarf seahorse (Hippocampus zosterae) during attacks on its copepod prey, Acartia tonsa. It is found that successful attacks often produce smaller or even no detectable hydrodynamic disturbances around the strike zone, when compared to unsuccessful attempts. In this paper, we will provide quantitative characterization of this ``low-flow'' zone. Further, to elucidate the role of a possible geometrical advantage of the seahorse's head in minimizing its bow wave, high-speed time resolved PIV measurements are conducted in a low-speed water tunnel. On-going analysis will provide insights and implications in understanding the dynamics of flows around the stagnation point at high Reynolds number flow. Sponsored by NSF.
Balcázar, José Luis; Planas, Miquel; Pintado, José
A Gram-positive, aerobic, non-motile, non-sporulating, acid-fast, and rod-shaped bacterium (BFLP-6(T)), previously isolated from a seahorse (Hippocampus guttulatus) with tail rot, was studied using a polyphasic taxonomic approach. Growth occurred at 15-35 °C (optimum 25 °C), at pH 5.0-10.0 (optimum pH 7.0) and at NaCl concentrations between 0 and 6 % (w/v). The G+C content of DNA was 66.7 mol%. The predominant fatty acids were C(18:1) ω9c, C(16:0) and C(16:1) ω6c. A mycolic acid pattern of alpha-mycolates and keto-mycolates was detected. Analysis of concatenated sequences (16S rRNA, rpoB, ssrA and tuf genes), and chemotaxonomic and phenotypic features indicated that strain BFLP-6(T) represents a novel species within the genus Mycobacterium, for which the name Mycobacterium hippocampi sp. nov. is proposed. The type strain is BFLP-6(T) (=DSM 45391(T) =LMG 25372(T)).
Haris, K.; Chakraborty, B.; Menezes, A.A.A.; Sreepada, R.A.; Fernandes, W.A.
, 2007), rhesus macaque (Fitch et al., 2002), meerkat (Townsend and Manser, 2011), corsican red deer (Facchini et al., 2003), dog (Riede et al., 2000; Tokuda et al., 2002; Volodina et al., 2006), red wolf (Schneider and Anderson, 2011), whale (Tyson et...–1767. Riede, T., Herzel, H., Mehwald, D., Seidner, W., Trumler, E., Tembrock, G., and Böhme, G. (2000). ‘‘Nonlinear phenomena in the natural howling of a dog–wolf mix,’’ J. Acoust. Soc. Am. 108, 1435– 1442. Riede, T., Owren, M. J., and Arcadi, A. C. (2004...
Sanaye, S.V.; Pise, N.M.; Pawar, A.P.; Parab, P.P.; Sreepada, R.A.; Pawar, H.B.; Revankar, A.D.
Chem. 119, 123–132. Martinez-Alvarez, R.M., Morales, A.E., Sanz, A., 2005. Antioxidant defences in fish: Biotic and abiotic factors. Rev. Fish Biol. Fish. 15, 75–88. Matsukawa, R., Dubinsky, Z., Kishimoto, E., Masaki, K., Masuda, Y., Takeuchi, T...
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
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
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.
Background Members of the family Syngnathidae share a unique reproductive mode termed male pregnancy. Males carry eggs in specialised brooding structures for several weeks and release free-swimming offspring. Here we describe a systematic investigation of pre-release development in syngnathid fishes, reviewing available data for 17 species distributed across the family. This work is complemented by in-depth examinations of the straight-nosed pipefish Nerophis ophidion, the black-striped pipefish Syngnathus abaster, and the potbellied seahorse Hippocampus abdominalis. Results We propose a standardised classification of early syngnathid development that extends from the activation of the egg to the release of newborn. The classification consists of four developmental periods – early embryogenesis, eye development, snout formation, and juvenile – which are further divided into 11 stages. Stages are characterised by morphological traits that are easily visible in live and preserved specimens using incident-light microscopy. Conclusions Our classification is derived from examinations of species representing the full range of brooding-structure complexity found in the Syngnathidae, including tail-brooding as well as trunk-brooding species, which represent independent evolutionary lineages. We chose conspicuous common traits as diagnostic features of stages to allow for rapid and consistent staging of embryos and larvae across the entire family. In view of the growing interest in the biology of the Syngnathidae, we believe that the classification proposed here will prove useful for a wide range of studies on the unique reproductive biology of these male-brooding fish. PMID:23273265
Kawaguchi, Mari; Nakano, Yuko; Kawahara-Miki, Ryouka; Inokuchi, Mayu; Yorifuji, Makiko; Okubo, Ryohei; Nagasawa, Tatsuki; Hiroi, Junya; Kono, Tomohiro; Kaneko, Toyoji
Syngnathiform fishes carry their eggs in a brood structure found in males. The brood structure differs from species to species: seahorses carry eggs within enclosed brood pouch, messmate pipefish carry eggs in the semi-brood pouch, and alligator pipefish carry eggs in the egg compartment on abdomen. These egg protection strategies were established during syngnathiform evolution. In the present study, we compared the hatching mode of protected embryos of three species. Electron microscopic observations revealed that alligator pipefish and messmate pipefish egg envelopes were thicker than those of seahorses, suggesting that the seahorse produces a weaker envelope. Furthermore, molecular genetic analysis revealed that these two pipefishes possessed the egg envelope-digesting enzymes, high choriolytic enzyme (HCE), and low choriolytic enzyme (LCE), as do many euteleosts. In seahorses, however, only HCE gene expression was detected. When searching the entire seahorse genome by high-throughput DNA sequencing, we did not find a functional LCE gene and only a trace of the LCE gene exon was found, confirming that the seahorse LCE gene was pseudogenized during evolution. Finally, we estimated the size and number of hatching gland cells expressing hatching enzyme genes by whole-mount in situ hybridization. The seahorse cells were the smallest of the three species, while they had the greatest number. These results suggest that the isolation of eggs from the external environment by paternal bearing might bring the egg envelope thin, and then, the hatching enzyme genes became pseudogenized. J. Exp. Zool. (Mol. Dev. Evol.) 9999B:XX-XX, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Zhao, Lu; Yuan, Shiaulou; Cao, Ying; Kallakuri, Sowjanya; Li, Yuanyuan; Kishimoto, Norihito; DiBella, Linda; Sun, Zhaoxia
Primary ciliary dyskinesia (PCD) is an autosomal recessive disease caused by defective cilia motility. The identified PCD genes account for about half of PCD incidences and the underlying mechanisms remain poorly understood. We demonstrate that Reptin/Ruvbl2, a protein known to be involved in epigenetic and transcriptional regulation, is essential for cilia motility in zebrafish. We further show that Reptin directly interacts with the PCD protein Lrrc6/Seahorse and this interaction is critical for the in vivo function of Lrrc6/Seahorse in zebrafish. Moreover, whereas the expression levels of multiple dynein arm components remain unchanged or become elevated, the density of axonemal dynein arms is reduced in reptin(hi2394) mutants. Furthermore, Reptin is highly enriched in the cytosol and colocalizes with Lrrc6/Seahorse. Combined, these results suggest that the Reptin-Lrrc6/Seahorse complex is involved in dynein arm formation. We also show that although the DNA damage response is induced in reptin(hi2394) mutants, it remains unchanged in cilia biogenesis mutants and lrrc6/seahorse mutants, suggesting that increased DNA damage response is not intrinsic to ciliary defects and that in vertebrate development, Reptin functions in multiple processes, both cilia specific and cilia independent.
Whan, A.; Mitchell, L.A.
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
Berumen, Laura Cristina; Rodríguez, Angelina; Miledi, Ricardo; García-Alcocer, Guadalupe
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
Full Text Available Abstract Background Members of the family Syngnathidae share a unique reproductive mode termed male pregnancy. Males carry eggs in specialised brooding structures for several weeks and release free-swimming offspring. Here we describe a systematic investigation of pre-release development in syngnathid fishes, reviewing available data for 17 species distributed across the family. This work is complemented by in-depth examinations of the straight-nosed pipefish Nerophis ophidion, the black-striped pipefish Syngnathus abaster, and the potbellied seahorse Hippocampus abdominalis. Results We propose a standardised classification of early syngnathid development that extends from the activation of the egg to the release of newborn. The classification consists of four developmental periods – early embryogenesis, eye development, snout formation, and juvenile – which are further divided into 11 stages. Stages are characterised by morphological traits that are easily visible in live and preserved specimens using incident-light microscopy. Conclusions Our classification is derived from examinations of species representing the full range of brooding-structure complexity found in the Syngnathidae, including tail-brooding as well as trunk-brooding species, which represent independent evolutionary lineages. We chose conspicuous common traits as diagnostic features of stages to allow for rapid and consistent staging of embryos and larvae across the entire family. In view of the growing interest in the biology of the Syngnathidae, we believe that the classification proposed here will prove useful for a wide range of studies on the unique reproductive biology of these male-brooding fish.
van der Windt, Gerritje J. W.; Chang, Chih-Hao; Pearce, Erika L.
This unit contains several protocols to determine the energy utilization of T cells in real-time using a Seahorse Extracellular Flux Analyzer (http://www.seahorsebio.com). The advantages to using this machine over traditional metabolic assays include the simultaneous measurement of glycolysis and
Van Look, Katrien J W; Dzyuba, Borys; Cliffe, Alex; Koldewey, Heather J; Holt, William V
Uniquely among vertebrates, seahorses and pipefishes (Family Syngnathidae) incubate their eggs within a male brood pouch. This has contributed to a widespread, but poorly founded belief, that the eggs are fertilised using spermatozoa that are deposited directly into the brood pouch via an internal sperm duct. Anatomical dissections showed, however, not only that direct sperm deposition into the pouch is physically impossible, but that spermatozoa must somehow travel a significant distance (>4 mm) outside the body of the male, to reach and fertilise eggs in the pouch. Observations of courtship and mating behaviour also revealed that the pouch closes immediately after mating, and that sperm transfer must occur within a time window of no more than 6 s. In addition to this, the yellow seahorse produces extraordinarily low quantities of dimorphic spermatozoa, but is nevertheless highly fertile and can produce broods that exceed 100 embryos. The entire fertilisation process in seahorses is therefore uniquely efficient among vertebrates, yet paradoxically involves several steps that would seem to complicate, and even appear to prevent, the interaction of the gametes. Although we are still unable to describe the exact fertilisation mechanism, we speculate that spermatozoa are ejaculated into a mixture of ovarian fluid and eggs, while the male and female are in close contact. Thereafter, this mixture must enter the pouch, whereupon the spermatozoa encounter seawater. These observations also support the view, indirectly inferred in previous publications, that sperm competition in seahorses is not only non-existent but impossible.
Ryu, BoMi; Qian, Zhong-Ji; Kim, Se-Kwon
Considerable efforts have been taken to identify natural peptides as potential bioactive substances. In this study, novel peptide (SHP-1) derived from seahorse (Hippocampus, Syngnathidae) hydrolysate was explored for its inhibitory effects on collagen release in arthritis with the investigation of its underlying mechanism of action. The efficacy of SHP-1 was determined on cartilage protective effects such as inhibition of collagen and GAG release. SHP-1 was able to suppress not only the expression of collagenases 1 and 3, but also the production of NO via down-regulation of iNOS. However, it presented an irrelevant effect on the level of GAG release in chondrocytic and osteoblastic cells. Inhibition of collagen release by SHP-1 is associated with restraining the phosphorylation of NF-kappaB and p38 kinase cascade. Therefore, it could be suggested that SHP-1 has a potential to be used in arthritis treatment.
Full Text Available The perception of elements in a system often creates their interdependence, interconditionality, and suppression. The lines from a basic geometrical element have become the model of a reductive world based on isolation according to certain criteria such as function, structure, and social organization. Their traces are experienced in the contemporary world as fragments or ruins of a system of domination of an assumed hierarchical unity. How can one release oneself from such dependence or determinism? How can the lines become less “systematic” and forms more autonomous, and less reductive? How is a form released from modernistic determinism on the new controversial ground? How can these elements or forms of representation become forms of action in the present complex world? In this paper, the meaning of lines through the ideas of Le Corbusier, Leonidov, Picasso, and Hitchcock is presented. Spatial research was made through a series of examples arising from the projects of the architectural studio “Residential Transformations”, which was a backbone for mapping the possibilities ranging from playfulness to exactness, as tactics of transformation in the different contexts of the contemporary world.
Iuso, Arcangela; Repp, Birgit; Biagosch, Caroline; Terrile, Caterina; Prokisch, Holger
Working with isolated mitochondria is the gold standard approach to investigate the function of the electron transport chain in tissues, free from the influence of other cellular factors. In this chapter, we outline a detailed protocol to measure the rate of oxygen consumption (OCR) with the high-throughput analyzer Seahorse XF96. More importantly, this protocol wants to provide practical tips for handling many different samples at once, and take a real advantage of using a high-throughput system. As a proof of concept, we have isolated mitochondria from brain, heart, liver, muscle, kidney, and lung of a wild-type mouse, and measured basal respiration (State II), ADP-stimulated respiration (State III), non-ADP-stimulated respiration (State IV o ), and FCCP-stimulated respiration (State III u ) using respiratory substrates specific to the respiratory chain complex I (RCCI) and complex II (RCCII). Mitochondrial purification and Seahorse runs were performed in less than eight working hours.
U, Fe, Mn, Ni, Cu, Zn and Co data for the sediment in both Key and Seahorse lakes, which overlie portions of known economic uranium deposits in the region, are presented. With the exception of U, Fe and Mn, the elemental distributions can be considered anomalous, in a statistical sense, in both lakes. The U values are of particular interest in that Key Lake is not anomalous, whereas Seahorse Lake is markedly anomalous. Tentative correlations made with background data from other surveys in attempt to differentiate between anomalous and background values indicate that deviations from linearity in a distribution, and not absolute mean or maximum values, are indicative of anomalous samples within the distribution.
Wilson, Anthony Bruce; Ahnesjö, Ingrid; Vincent, Amanda C. J.; Meyer, Axel
Modern theory predicts that relative parental investment of the sexes in their young is a key factor responsible for sexual selection. Seahorses and pipefishes (family Syngnathidae) are extraordinary among fishes in their remarkable adaptations for paternal care and frequent occurrences of sex-role reversals (i.e., female-female competition for mates), offering exceptional opportunities to test predictions of sexual selection theory. During mating, the female transfers eggs into or onto speci...
Wilson, Anthony B; Ahnesjö, Ingrid; Vincent, Amanda C J; Meyer, Axel
Modern theory predicts that relative parental investment of the sexes in their young is a key factor responsible for sexual selection. Seahorses and pipefishes (family Syngnathidae) are extraordinary among fishes in their remarkable adaptations for paternal care and frequent occurrences of sex-role reversals (i.e., female-female competition for mates), offering exceptional opportunities to test predictions of sexual selection theory. During mating, the female transfers eggs into or onto specialized egg-brooding structures that are located on either the male's abdomen or its tail, where they are osmoregulated, aerated, and nourished by specially adapted structures. All syngnathid males exhibit this form of parental care but the brooding structures vary, ranging from the simple ventral gluing areas of some pipefishes to the completely enclosed pouches found in seahorses. We present a molecular phylogeny that indicates that the diversification of pouch types is positively correlated with the major evolutionary radiation of the group, suggesting that this extreme development and diversification of paternal care may have been an important evolutionary innovation of the Syngnathidae. Based on recent studies that show that the complexity of brooding structures reflects the degree of paternal investment in several syngnathid species, we predicted sex-role reversals to be more common among species with more complex brooding structures. In contrast to this prediction, however, both parsimony- and likelihood-based reconstructions of the evolution of sex-role reversal in pipefishes and seahorses suggest multiple shifts in sex roles in the group, independent from the degree of brood pouch development. At the same time, our data demonstrate that sex-role reversal is positively associated with polygamous mating patterns, whereas most nonreversed species mate monogamously, suggesting that selection for polygamy or monogamy in pipefishes and seahorses may strongly influence sex
Lange, Miranda; Zeng, Yan; Knight, Andrew; Windebank, Anthony; Trushina, Eugenia
Changes in mitochondrial dynamics and function contribute to progression of multiple neurodegenerative diseases including peripheral neuropathies. The Seahorse Extracellular Flux XF24 analyzer provides a comprehensive assessment of the relative state of glycolytic and aerobic metabolism in live cells making this method instrumental in assessing mitochondrial function. One of the most important steps in the analysis of mitochondrial respiration using the Seahorse XF24 analyzer is plating a uniform monolayer of firmly attached cells. However, culturing of primary dorsal root ganglion (DRG) neurons is associated with multiple challenges, including their propensity to form clumps and detach from the culture plate. This could significantly interfere with proper analysis and interpretation of data. We have tested multiple cell culture parameters including coating substrates, culture medium, XF24 microplate plastics, and plating techniques in order to optimize plating conditions. Here we describe a highly reproducible method to obtain neuron-enriched monolayers of securely attached dissociated primary embryonic (E15) rat DRG neurons suitable for analysis with the Seahorse XF24 platform.
Miranda L. Lange
Full Text Available Changes in mitochondrial dynamics and function contribute to progression of multiple neurodegenerative diseases including peripheral neuropathies. The Seahorse Extracellular Flux XF24 analyzer provides a comprehensive assessment of the relative state of glycolytic and aerobic metabolism in live cells making this method instrumental in assessing mitochondrial function. One of the most important steps in the analysis of mitochondrial respiration using the Seahorse XF24 analyzer is plating a uniform monolayer of firmly attached cells. However, culturing of primary dorsal root ganglion (DRG neurons is associated with multiple challenges, including their propensity to form clumps and detach from the culture plate. This could significantly interfere with proper analysis and interpretation of data. We have tested multiple cell culture parameters including coating substrates, culture medium, XF24 microplate plastics, and plating techniques in order to optimize plating conditions. Here we describe a highly reproducible method to obtain neuron-enriched monolayers of securely attached dissociated primary embryonic (E15 rat DRG neurons suitable for analysis with the Seahorse XF24 platform.
Lee, Andy C. H.; Yeung, Lok-Kin; Barense, Morgan D.
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
Andy C. H. Lee
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.
Purification of a peptide from seahorse, that inhibits TPA-induced MMP, iNOS and COX-2 expression through MAPK and NF-kappaB activation, and induces human osteoblastic and chondrocytic differentiation.
Ryu, BoMi; Qian, Zhong-Ji; Kim, Se-Kwon
Ongoing efforts to search for naturally occurring, bioactive substances for the amelioration of arthritis have led to the discovery of natural products with substantial bioactive properties. The seahorse (Hippocampus kuda Bleeler), a telelost fish, is one source of known beneficial products, yet has not been utilized for arthritis research. In the present work, we have purified and characterized a bioactive peptide from seahorse hydrolysis. Among the hydrolysates tested, pronase E-derived hydrolysate exhibited the highest alkaline phosphatase (ALP) activity, a phenotype marker of osteoblast and chondrocyte differentiation. After its separation from the hydrolysate by several purification steps, the peptide responsible for the ALP activity was isolated and its sequence was identified as LEDPFDKDDWDNWK (1821Da). We have shown that the isolated peptide induces differentiation of osteoblastic MG-63 and chondrocytic SW-1353 cells by measuring ALP activity, mineralization and collagen synthesis. Our results indicate that the peptide acts during early to late stages of differentiation in MG-63 and SW-1353 cells. We also assessed the concentration dependence of the peptide's inhibition of MMP (-1, -3 and -13), iNOS and COX-2 expression after treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA), a common form of phorbol ester. The peptide also inhibited NO production in MG-63 and SW-1353 cells. To elucidate the mechanisms by which the peptide acted, we examined its effects on TPA-induced MAPKs/NF-kappaB activation and determined that the peptide treatment significantly reduced p38 kinase/NF-kappaB in MG-63 cells and MAPKs/NF-kappaB in SW-1353 cells.
Teske, Peter R; Hamilton, Healy; Matthee, Conrad A; Barker, Nigel P
The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation) is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses), as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a) the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b) the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c) continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns. Comparisons of pairwise genetic distances among the seahorse species hypothesized to have diverged as a result of the closure of the Central American Seaway with those of published teleost sequences having the same distribution patterns show that the seahorses were among the last to diverge. This suggests that their
Matthee Conrad A
Full Text Available Abstract Background The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses, as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns. Results Comparisons of pairwise genetic distances among the seahorse species hypothesized to have diverged as a result of the closure of the Central American Seaway with those of published teleost sequences having the same distribution patterns show that the seahorses were among the last to
Praet, Tomas; Adriaens, Dominique; Van Cauter, Sofie; Masschaele, Bert; De Beule, Matthieu; Verhegghe, Benedict
Technological advances are often inspired by nature, considering that engineering is frequently faced by the same challenges as organisms in nature. One such interesting challenge is creating a structure that is at the same time stiff in a certain direction, yet flexible in another. The seahorse tail combines both radial stiffness and bending flexibility in a particularly elegant way: even though the tail is covered in a protective armour, it still shows sufficient flexibility to fully function as a prehensile organ. We therefore study the complex mechanics and dynamics of the musculoskeletal system of the seahorse tail from an engineering point of view. The seahorse tail derives its combination of flexibility and resilience from a chain of articulating skeletal segments. A versatile dynamic model of those segments was constructed, on the basis of automatic recognition of joint positions and muscle attachments. Both muscle structures that are thought to be responsible for ventral and ventral-lateral tail bending, namely the median ventral muscles and the hypaxial myomere muscles, were included in the model. Simulations on the model consist mainly of dynamic multi-body simulations. The results show that the sequential structure of uniformly shaped bony segments can remain flexible because of gliding joints that connect the corners of the segments. Radial stiffness on the other hand is obtained through the support that the central vertebra provides to the tail plating. Such insights could help in designing biomedical instruments that specifically require both high bending flexibility and radial stiffness (e.g. flexible stents and steerable catheters). Copyright © 2012 John Wiley & Sons, Ltd.
Marinangeli, Claudia; Kluza, Jérome; Marchetti, Philippe; Buée, Luc; Vingtdeux, Valérie
AMP-activated protein kinase (AMPK) is the intracellular master energy sensor and metabolic regulator. AMPK is involved in cell energy homeostasis through the regulation of glycolytic flux and mitochondrial biogenesis. Interestingly, metabolic dysfunctions and AMPK deregulations are observed in many neurodegenerative diseases, including Alzheimer's. While these deregulations could play a key role in the development of these diseases, the study of metabolic fluxes has remained quite challenging and time-consuming. In this chapter, we describe the Seahorse XFe respirometry assay as a fundamental experimental tool to investigate the role of AMPK in controlling and modulating cell metabolic fluxes in living and intact differentiated primary neurons. The Seahorse XFe respirometry assay allows the real-time monitoring of glycolytic flux and mitochondrial respiration from different kind of cells, tissues, and isolated mitochondria. Here, we specify a protocol optimized for primary neuronal cells using several energy substrates such as glucose, pyruvate, lactate, glutamine, and ketone bodies. Nevertheless, this protocol can easily be adapted to monitor metabolic fluxes from other types of cells, tissues, or isolated mitochondria by taking into account the notes proposed for each key step of this assay.
Mäkelä, M. M.; Haikala, L. K.; Gahm, G. F.
Context. The Rosette nebula is an H II region ionized mainly by the stellar cluster NGC 2244. Elephant trunks, globules, and globulettes are seen at the interface where the H II region and the surrounding molecular shell meet. Aims: We have observed a field in the northwestern part of the Rosette nebula where we study the small globules protruding from the shell. Our aim is to measure their properties and study their star-formation history in continuation of our earlier study of the features of the region. Methods: We imaged the region in broadband near-infrared (NIR) JsHKs filters and narrowband H2 1-0 S(1), Pβ, and continuum filters using the SOFI camera at the ESO/NTT. The imaging was used to study the stellar population and surface brightness, create visual extinction maps, and locate star formation. Mid-infrared (MIR) Spitzer IRAC and WISE and optical NOT images were used to further study the star formation and the structure of the globules. The NIR and MIR observations indicate an outflow, which is confirmed with CO observations made with APEX. Results: The globules have mean number densities of 4.6 × 104 cm-3. Pβ is seen in absorption in the cores of the globules where we measure visual extinctions of 11-16 mag. The shell and the globules have bright rims in the observed bands. In the Ks band 20 to 40% of the emission is due to fluorescent emission in the 2.12 μmH2 line similar to the tiny dense globulettes we studied earlier in a nearby region. We identify several stellar NIR excess candidates and four of them are also detected in the Spitzer IRAC 8.0 μm image and studied further. We find an outflow with a cavity wall bright in the 2.124 μmH2 line and at 8.0 μm in one of the globules. The outflow originates from a Class I young stellar object (YSO) embedded deep inside the globule. An Hα image suggests the YSO drives a possible parsec-scale outflow. Despite the morphology of the globule, the outflow does not seem to run inside the dusty fingers
Wei, Changyong; Heitmeier, Monique; Hruz, Paul W; Shanmugam, Mala
Glucose is metabolized through anaerobic glycolysis and aerobic oxidative phosphorylation (OXPHOS). Perturbing glucose uptake and its subsequent metabolism can alter both glycolytic and OXPHOS pathways and consequently lactate and/or oxygen consumption. Production and secretion of lactate, as a consequence of glycolysis, leads to acidification of the extracellular medium. Molecular oxygen is the final electron acceptor in the electron transport chain, facilitating oxidative phosphorylation of ADP to ATP. The alterations in extracellular acidification and/or oxygen consumption can thus be used as indirect readouts of glucose metabolism and assessing the impact of inhibiting glucose transport through specific glucose transporters (GLUTs). The Seahorse bioenergetics analyzer can measure both the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). The proposed methodology affords a robust, high-throughput method to screen for GLUT inhibition in cells engineered to express specific GLUTs, providing live cell read-outs upon GLUT inhibition.
Gemmell, Brad J; Sheng, Jian; Buskey, Edward J
Syngnathid fish (seahorses, pipefish and sea dragons) are slow swimmers yet capture evasive prey (copepods) using a technique known as the 'pivot' feeding, which involves rapid movement to overcome prey escape capabilities. However, this feeding mode functions only at short range and requires approaching very closely to hydrodynamically sensitive prey without triggering an escape. Here we investigate the role of head morphology on prey capture using holographic and particle image velocimetry (PIV). We show that head morphology functions to create a reduced fluid deformation zone, minimizing hydrodynamic disturbance where feeding strikes occur (above the end of the snout), and permits syngnathid fish to approach highly sensitive copepod prey (Acartia tonsa) undetected. The results explain how these animals can successfully employ short range 'pivot' feeding effectively on evasive prey. The need to approach prey with stealth may have selected for a head shape that produces lower deformation rates than other fish.
Lay, Sui; Sanislav, Oana; Annesley, Sarah J; Fisher, Paul R
Mitochondria not only play a critical and central role in providing metabolic energy to the cell but are also integral to the other cellular processes such as modulation of various signaling pathways. These pathways affect many aspects of cell physiology, including cell movement, growth, division, differentiation, and death. Mitochondrial dysfunction which affects mitochondrial bioenergetics and causes oxidative phosphorylation defects can thus lead to altered cellular physiology and manifest in disease. The assessment of the mitochondrial bioenergetics can thus provide valuable insights into the physiological state, and the alterations to the state of the cells. Here, we describe a method to successfully use the Seahorse XF(e)24 Extracellular Flux Analyzer to assess the mitochondrial respirometry of the cellular slime mold Dictyostelium discoideum.
Luz, Anthony L.; Smith, Latasha L.; Rooney, John P.
Mitochondria are critical for their role in ATP production as well as multiple nonenergetic functions, and mitochondrial dysfunction is causal in myriad human diseases. Less well appreciated is the fact that mitochondria integrate environmental and inter- as well as intracellular signals to modulate function. Because mitochondria function in an organismal milieu, there is need for assays capable of rapidly assessing mitochondrial health in vivo. Here, using the Seahorse XFe24 Extracellular Flux Analyzer and the pharmacological inhibitors dicyclohexylcarbodiimide (DCCD, ATP synthase inhibitor), carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP, mitochondrial uncoupler) and sodium azide (cytochrome c oxidase inhibitor), we describe how to obtain in vivo measurements of the fundamental parameters (basal oxygen consumption rate (OCR), ATP-linked respiration, maximal OCR, spare respiratory capacity and proton leak) of the mitochondrial respiratory chain in the model organism Caenorhabditis elegans. PMID:26523474
Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.
Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.
Wingenfeld, Katja; Wolf, Oliver T
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
Chakraborty, B.; Saran, A.K.; Kuncolienker, D.S.; Sreepada, R.A.; Haris, K.; Fernandes, W.A
based on the assumption of combinations of normal / Gaussian distributions indicate well fitted multimodal curves generated using MATLAB (Math Works Inc 2005) programs. Out of the twenty three clicks, four clicks (two clicks of 16 and 18cm male... Society of America 115: 2331-2333. Malamud BD, Turcotte DL. 1999. Self affine time series: measures of weak and strong persistence. Journal of Statistical Planning and Inference 80:173-196. MATLAB, Curve Fitting toolbox, Math Works Inc 2005. Available...
Murugan, A.; Dhanya, S.; Pawar, H.; Sreepada, R.A.; Rajagopal, S.; Balasubramanian, T.
male length (HT in mm) 12.5 0.8 12.1 – 13.3 14 Adult female length (HT in mm) 12.7 0.91 12.4 – 13.1 14 Adult male wet weight (g) 7.1 0.59 6.5 – 7.4 14 Adult female wet weight (g) 7.8 0.73 6.7 – 8.2 14 Table 2. Captive breeding of the three spotted...
Shah-Simpson, Sheena; Pereira, Camila F A; Dumoulin, Peter C; Caradonna, Kacey L; Burleigh, Barbara A
Energy metabolism is an attractive target for the development of new therapeutics against protozoan pathogens, including Trypanosoma cruzi, the causative agent of human Chagas disease. Despite emerging evidence that mitochondrial electron transport is essential for the growth of intracellular T. cruzi amastigotes in mammalian cells, fundamental knowledge of mitochondrial energy metabolism in this parasite life stage remains incomplete. The Clark-type electrode, which measures the rate of oxygen consumption, has served as the traditional tool to study mitochondrial energetics and has contributed to our understanding of it in T. cruzi. Here, we evaluate the Seahorse XF(e)24 extracellular flux platform as an alternative method to assess mitochondrial bioenergetics in isolated T. cruzi parasites. We report optimized assay conditions used to perform mitochondrial stress tests with replicative life cycle stages of T. cruzi using the XF(e)24 instrument, and discuss the advantages and potential limitations of this methodology, as applied to T. cruzi and other trypanosomatids. Copyright © 2016 Elsevier B.V. All rights reserved.
van der Windt, Gerritje J W; Chang, Chih-Hao; Pearce, Erika L
This unit contains several protocols to determine the energy utilization of T cells in real-time using a Seahorse Extracellular Flux Analyzer (http://www.seahorsebio.com). The advantages to using this machine over traditional metabolic assays include the simultaneous measurement of glycolysis and mitochondrial respiration, in real-time, on relatively small numbers of cells, without any radioactivity. The Basic Protocol describes a standard mitochondrial stress test on the XF(e) 96, which yields information about oxidative phosphorylation and glycolysis, two energy-generating pathways. The alternate protocols provide examples of adaptations to the Basic Protocol, including adjustments for the use of the XF(e) 24. A protocol for real-time bioenergetic responses to T cell activation allows for the analysis of immediate metabolic changes after T cell receptor stimulation. Specific substrate utilization can be determined by the use of differential assay media, or the injection of drugs that specifically affect certain metabolic processes. Accurate cell numbers, purity, and viability are critical to obtain reliable results. Copyright © 2016 John Wiley & Sons, Inc.
Kuljeet Singh Anand
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.
Jones, A G; Avise, J C
In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic mating systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic mating systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic mating systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the mating system than previously available techniques. Finally, these genetic studies of syngnathid mating systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.
Baddeley, Alan; Jarrold, Christopher; Vargha-Khadem, Faraneh
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.
Leysen, Heleen; Jouk, Philippe; Brunain, Marleen; Christiaens, Joachim; Adriaens, Dominique
The long snout of pipefishes and seahorses (Syngnathidae, Gasterosteiformes) is formed as an elongation of the ethmoid region. This is in contrast to many other teleosts with elongate snouts (e.g., butterflyfishes) in which the snout is formed as an extension of the jaws. Syngnathid fishes perform very fast suction feeding, accomplished by powerful neurocranial elevation and hyoid retraction. Clearly, suction through a long and narrow tube and its hydrodynamic implications can be expected to require certain adaptations in the cranium, especially in musculoskeletal elements of the feeding apparatus. Not much is known about which skeletal elements actually support the snout and what the effect of elongation is on related structures. Here, we give a detailed morphological description of the cartilaginous and bony feeding apparatus in both juvenile and adult Syngnathus rostellatus and Hippocampus capensis. Our results are compared with previous morphological studies of a generalized teleost, Gasterosteus aculeatus. We found that the ethmoid region is elongated early during development, with the ethmoid plate, the hyosymplectic, and the basihyal cartilage being extended in the chondrocranium. In the juveniles of both species almost all bones are forming, although only as a very thin layer. The elongation of the vomeral, mesethmoid, quadrate, metapterygoid, symplectic, and preopercular bones is already present. Probably, because of the long and specialized parental care which releases advanced developmental stages from the brooding pouch, morphology of the feeding apparatus of juveniles is already very similar to that of the adults. We describe morphological features related to snout elongation that may be considered adaptations for suction feeding; e.g. the peculiar shape of the interhyal bone and its saddle-shaped articulation with the posterior ceratohyal bone might aid in explosive hyoid retraction by reducing the risk of hyoid dislocation.
Chen, Huayue; Iinuma, Mitsuo; Onozuka, Minoru; Kubo, Kin-Ya
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.
Chen, LiPing; Shen, XuanRi; Chen, GuoHua; Cao, XianYing; Yang, Jian
Three-Spot seahorse is a traditional medicine in Asian countries. However, the alcohol extract is largely unknown for its anti-inflammatory activity. This study aimed at elucidating fraction of potent anti-inflammatory activity of seahorse. A systematic solvent extraction method of liquid-liquid fractionation of ethanol crude extract gave four fractions petroleum ether (PE), and ethyl acetate (EtOAc), water saturated butanol (n-BuOH), water (H2O). In this study, PE extract was selected for further study after preliminary screening test, and was connected to silica column chromatography and eluted with different polarity of mobile phases, and obtained four active fractions (Fr I, Fr II, Fr III, Fr IV). Effect of separated fractions on inflammation was investigated in lipopolysaccharide (LPS) stimulated murine RAW264.7 cells in vitro. The result shows that seahorse extract was capable of inhibiting the production of nitric oxide (NO) significantly in a dose dependent manner and exhibited no notable cytotoxicity on cell viability. IC50 of fraction IV was 36.31 μg/mL, indicating that separated fraction possessed potent NO inhibitory activity against LPS-induced inflammatory response, thus, demonstrated its in vitro anti-inflammatory potentiality, it may be at least partially explained by the presence of anti-inflammation active substances, phenolic compounds, phospholipids and polyunsaturated fatty acids, especially phospholipids and polyunsaturated fatty acids. It could be suggested that seahorse lipid-soluble components could be used in functional food and anti-inflammatory drug preparations.
Gondi, Vinai; Tome, Wolfgang A.; Mehta, Minesh P.
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.
Howard, Marc W.; Eichenbaum, Howard
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
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.
Kelemen, Eduard; Fenton, A.A.
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
Divakaruni, Ajit S; Rogers, George W; Murphy, Anne N
Measurements of mitochondrial respiration in intact cells can help define metabolism and its dysregulation in fields such as cancer, metabolic disease, immunology, and neurodegeneration. Although cells can be offered various substrates in the assay medium, many cell types can oxidize stored pools of energy substrates. A general bioenergetic profile can therefore be obtained using intact cells, but the inability to control substrate provision to the mitochondria can restrict an in-depth, mechanistic understanding. Mitochondria can be isolated from intact cells, but the yield and quality of the end product is often poor and prone to subselection during isolation. Plasma membrane permeabilization of cells provides a solution to this challenge, allowing experimental control of the medium surrounding the mitochondria. This unit describes techniques to measure respiration in permeabilized adherent cells using a Seahorse XF Analyzer or permeabilized suspended cells in a Hansatech Oxygraph. Copyright © 2014 John Wiley & Sons, Inc.
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.
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
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
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.
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)
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.
Barker, Gareth R. I.; Warburton, Elizabeth C.
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 ...
Kristin Lynn Eckel-Mahan
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 . 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.
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
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 Â© 2016 Elsevier Inc. All rights reserved.
Atmaca, Murad; Baykara, Sema; Ozer, Omer; Korkmaz, Sevda; Akaslan, Unsal; Yildirim, Hanefi
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.
Ramirez, Steve; Liu, Xu; Lin, Pei-Ann; Suh, Junghyup; Pignatelli, Michele; Redondo, Roger L; Ryan, Tomás J; Tonegawa, Susumu
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.
Jamie L Hanson
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.
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.
LePage, Véronique; Dutton, Christopher J; Kummrow, Maya; McLelland, David J; Young, Karrie; Lumsden, John S
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.
D. O. Assonov
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
von Allmen, David Yoh; Wurmitzer, Karoline; Martin, Ernst; Klaver, Peter
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.
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.
Shailesh Kumar Gupta
developed, whereas optic lobes were rounded and large. The exact boundary line of the hippocampus was not discernable. In hippocampus histology, two categories of neuron local circuit neurons and projection neurons, high vascularization and epididymal lining of lateral ventricle were observed. Hippocampal neurons were comparatively larger without any distinct layers. The afferent neurons projected to the medium septum.
Gupta, Shailesh Kumar; Behera, Kumaresh; Pradhan, C. R.; Mandal, Arun Kumar; Sethy, Kamdev; Behera, Dayanidhi; Shinde, Kuladip Prakash
, whereas optic lobes were rounded and large. The exact boundary line of the hippocampus was not discernable. In hippocampus histology, two categories of neuron local circuit neurons and projection neurons, high vascularization and epididymal lining of lateral ventricle were observed. Hippocampal neurons were comparatively larger without any distinct layers. The afferent neurons projected to the medium septum. PMID:27284228
Chebat, Daniel-Robert; Chen, Jan-Kai; Schneider, Fabien
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...
Duka, T.; Wuester, M.; Schubert, P.; Stoiber, R.; Herz, A.
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.)
Palacios, J.M.; Reubi, J.C.; Maurer, R.
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)
Plessen, Kerstin J; Bansal, Ravi; Zhu, Hongtu
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
Lingzhi Kong; Xihong Wu; Liang Li
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.
Bett, David; Murdoch, Lauren H; Wood, Emma R; Dudchenko, Paul A
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.
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.
Wagner, Tobias; Axmacher, Nikolai; Lehnertz, Klaus; Elger, Christian E; Fell, Jürgen
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.
Stollery, Brian; Christian, Leonie
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.
Striedter, Georg F
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.
Moscovitch, Morris; Cabeza, Roberto; Winocur, Gordon; Nadel, Lynn
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.
Preston, Alison R.; Eichenbaum, Howard
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
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.
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
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.
Autio, Henri; Mätlik, Kert; Rantamäki, Tomi; Lindemann, Lothar; Hoener, Marius C; Chao, Moses; Arumäe, Urmas; Castrén, Eero
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
Besser, Limor; Chorin, Ehud; Sekler, Israel; Silverman, William F; Atkin, Stan; Russell, James T; Hershfinkel, Michal
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.
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.
Gispen, W.H.; Maaswinkel, H.; Baars, A.M.; Spruijt, B.M.
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
Groen, W.B.; Teluij, M.; Buitelaar, J.K.; Tendolkar, I.
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
Kim, Eun Joo; Pellman, Blake; Kim, Jeansok J.
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…
Bird, Chris M
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.
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)
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.)
Soga, Keishi; Kamijo, Keita; Masaki, Hiroaki
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.
Groen, Wouter; Teluij, Michelle; Buitelaar, Jan; Tendolkar, Indira
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.…
Drew, Liam J.; Fusi, Stefano; Hen, René
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…
Lodygensky, Gregory A; Seghier, Mohammed L; Warfield, Simon K; Tolsa, Cristina Borradori; Sizonenko, Stephane; Lazeyras, François; Hüppi, Petra S
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.
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.
U.S. Environmental Protection Agency — Metadata for figures presented in manuscript reporting bioenergetic effects of exposure to environmentally relevant organic compound in human airway epithelial...
Hess, J.; Jensen, Claus V.; Diemer, Nils Henrik
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...
Kim, Jangjin; Castro, Leyre; Wasserman, Edward A; Freeman, John H
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
Wagatsuma, Hiroaki; Yamaguchi, Yoko
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
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K. Yu. Maksimova
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
Andon Nicholas PLACZEK; Tao A ZHANG; John Anthony DANI
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.
Oskan, F.; Ganswindt, U.; Schwarz, S.B.; Manapov, F.; Belka, C.; Niyazi, M.
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
Bruno P. Carreira
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.
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.
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
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
Roy, Avik; Kundu, Madhuchhanda; Jana, Malabendu; Mishra, Rama K.; Yung, Yeni; Luan, Chi-Hao; Gonzalez, Frank J.; Pahan, Kalipada
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...
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.
Wagatsuma, Hiroaki; Yamaguchi, Yoko
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...
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.
Wentz, Christian T.; Magavi, Sanjay S.P.
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...
Reyes-Haro, Daniel; Labrada-Moncada, Francisco Emmanuel; Varman, Durairaj Ragu; Krüger, Janina; Morales, Teresa; Miledi, Ricardo; Martínez-Torres, Ataúlfo
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.
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
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.
Kaycie Kuss Tayler
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.
Sheldon, Signy; Levine, Brian
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.
Özlem Donat Eker
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
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
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
Teki, Sundeep; Kumar, Sukhbinder; von Kriegstein, Katharina; Stewart, Lauren; Lyness, C Rebecca; Moore, Brian C J; Capleton, Brian; Griffiths, Timothy D
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.
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
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.
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)
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.)
Reber, T P; Do Lam, A T A; Axmacher, N; Elger, C E; Helmstaedter, C; Henke, K; Fell, J
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
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.
Johnson, Adam; Varberg, Zachary; Benhardus, James; Maahs, Anthony; Schrater, Paul
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
Nordberg, A; Larsson, C; Adolfsson, R; Alafuzoff, I; Winblad, B [Uppsala Univ. (Sweden)
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.
Dalsgaard, Mads K; Madsen, Flemming F; Secher, Niels H
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...
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
At just over 10 meters above street level, the High Line extends three kilometers through three districts of Southwestern Manhattan in New York. It consists of simple steel construction, and previously served as an elevated rail line connection between Penn Station on 34th Street and the many....... The High Line project has been carried out as part of an open conversion strategy. The result is a remarkable urban architectural project, which works as a catalyst for the urban development of Western Manhattan. The greater project includes the restoration and reuse of many old industrial buildings...
Seahorse-derived peptide suppresses invasive migration of HT1080 fibrosarcoma cells by competing with intracellular α-enolase for plasminogen binding and inhibiting uPA-mediated activation of plasminogen.
Kim, Yong-Tae; Kim, Se-kwon; Jeon, You-Jin; Park, Sun Joo
α-Enolase is a glycolytic enzyme and a surface receptor for plasminogen. α-Enolase-bound plasminogen promotes tumor cell invasion and cancer metastasis by activating plasmin and consequently degrading the extracellular matrix degradation. Therefore, α-enolase and plasminogen are novel targets for cancer therapy. We found that the amino acid sequence of a peptide purified from enzymatic hydrolysates of seahorse has striking similarities to that of α-enolase. In this study, we report that this peptide competes with cellular α-enolase for plasminogen binding and suppresses urokinase plasminogen activator (uPA)-mediated activation of plasminogen, which results in decreased invasive migration of HT1080 fibrosarcoma cells. In addition, the peptide treatment decreased the expression levels of uPA compared to that of untreated controls. These results provide new insight into the mechanism by which the seahorse-derived peptide suppresses invasive properties of human cancer cells. Our findings suggest that this peptide could emerge as a potential therapeutic agent for cancer.
Sakimoto, Yuya; Okada, Kana; Hattori, Minoru; Takeda, Kozue; Sakata, Shogo
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.
Mariela F. Trinchero
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
Kumaran, Dharshan; Maguire, Eleanor A
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.
Engelhardt, Eliasz; Moreira, Denise M.; Laks, Jerson; Marinho, Valeska M.; Rozenthal, Marcia; Oliveira Junior, Amarino C.
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)
Cornelius, John Thor
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.
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.
Waser Jürgen; Fuchs Raphael; Ribicic Hrvoje; Schindler Benjamin; Blöschl Günther; Gröller Eduard
In this paper we present World Lines as a novel interactive visualization that provides complete control over multiple heterogeneous simulation runs. In many application areas decisions can only be made by exploring alternative scenarios. The goal of the suggested approach is to support users in this decision making process. In this setting the data domain is extended to a set of alternative worlds where only one outcome will actually happen. World Lines integrate simulation visualization and...
Ji, Jinzhao; Maren, Stephen
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…
Stewart, Christopher C.; Griffith, H. Randall; Okonkwo, Ozioma C.; Martin, Roy C.; Knowlton, Robert K.; Richardson, Elizabeth J.; Hermann, Bruce P.; Seidenberg, Michael
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,…
Hosseini-Sharifabad, Mohammad; Nyengaard, Jens Randel
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; ...
Oliveira, Ana M. M.; Hawk, Joshua D.; Abel, Ted; Havekes, Robbert
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…
Bultas, Margaret W; Pohlman, Shawn
The purpose of this interpretive phenomenological study was to gain a better understanding of the experiences of 11 mothers of preschool children with autism spectrum disorder (ASD). Mothers were interviewed three times over a 6 week period. Interviews were analyzed using interpretive methods. This manuscript highlights one particular theme-a positive perspective mothers described as the "silver lining." This "silver lining" represents optimism despite the adversities associated with parenting a child with ASD. A deeper understanding of this side of mothering children with ASD may help health care providers improve rapport, communication, and result in more authentic family centered care. Copyright © 2014 Elsevier Inc. All rights reserved.
Girardeau, Gabrielle; Inema, Ingrid; Buzsáki, György
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.
Jena B. Hales
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.
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...
Roy, Avik; Kundu, Madhuchhanda; Jana, Malabendu; Mishra, Rama K; Yung, Yeni; Luan, Chi-Hao; Gonzalez, Frank J; Pahan, Kalipada
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.
Keck, Tara; Lillis, Kyle P; Zhou, Yu-Dong; White, John A
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.
de Voogd, Lycia D; Klumpers, Floris; Fernández, Guillén; Hermans, Erno J
Declarative memories of stressful events are less prone to forgetting than mundane events. Animal research has demonstrated that such stress effects on consolidation of hippocampal-dependent memories require the amygdala. In humans, it has been shown that during learning, increased amygdala-hippocampal interactions are related to more efficient memory encoding. Animal models predict that following learning, amygdala-hippocampal interactions are instrumental to strengthening the consolidation of such declarative memories. Whether this is the case in humans is unknown and remains to be empirically verified. To test this, we analyzed data from a sample of 120 healthy male participants who performed an incidental encoding task and subsequently underwent resting-state functional MRI in a stressful and a neutral context. Stress was assessed by measures of salivary cortisol, blood pressure, heart rate, and subjective ratings. Memory was tested afterwards outside of the scanner. Our data show that memory was stronger in the stress context compared to the neutral context and that stress-induced cortisol responses were associated with this memory enhancement. Interestingly, amygdala-hippocampal connectivity during post-encoding awake rest regardless of context (stress or neutral) was associated with the enhanced memory performance under stress. Thus, our findings are in line with a role for intrinsic functional connectivity during rest between the amygdala and the hippocampus in the state effects of stress on strengthening memory. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
Albaidhani, Tahseen; Jassim, Sabah; Al-Assam, Hisham
The brain Hippocampus component is known to be responsible for memory and spatial navigation. Its functionality depends on the status of different blood vessels within the Hippocampus and is severely impaired by Alzheimer's disease as a result blockage of increasing number of blood vessels by accumulation of amyloid-beta (Aβ) protein. Accurate counting of blood vessels within the Hippocampus of mice brain, from microscopic images, is an active research area for the understanding of Alzheimer's disease. Here, we report our work on automatic detection of the Region of Interest, i.e. the region in which blood vessels are located. This area typically falls between the hippocampus edge and the line of neurons within the Hippocampus. This paper proposes a new method to detect and exclude the neuron line to improve the accuracy of blood vessel counting because some neurons on it might lead to false positive cases as they look like blood vessels. Our proposed solution is based on using trainable segmentation approach with morphological operations, taking into account variation in colour, intensity values, and image texture. Experiments on a sufficient number of microscopy images of mouse brain demonstrate the effectiveness of the developed solution in preparation for blood vessels counting.
Calderón, Naima; Betancourt, Luis; Hernández, Luis; Rada, Pedro
The ketogenic diet (KD) is acknowledged as an unconventional option in the treatment of epilepsy. Several lines of investigation point to a possible role of glutamate and gamma-aminobutyric acid (GABA) as main contributors in this protective effect. Other biomolecules could also be involved in the beneficial consequence of the KD, for example, the diamine agmatine has been suggested to block imidazole and glutamate NMDA receptor and serves as an endogenous anticonvulsant in different animal models of epilepsy. In the present report, we have used microdialysis coupled to capillary electrophoresis to monitor microdialysate levels of GABA, glutamate and agmatine in the hippocampus of rats submitted to a KD for 15days compared to rats on a normal rat chow diet. A significant increase in GABA and agmatine levels while no change in glutamate levels was observed. These results support the notion that the KD modifies different transmitters favoring inhibitory over excitatory neurotransmitters. Copyright © 2017 Elsevier B.V. All rights reserved.
Licht, Cecilie Löe; Marcussen, Anders Bue; Wegener, Gregers
The 5-hydroxytryptamine (5-HT(4)) receptor may be implicated in depression and is a new potential target for antidepressant treatment. We have investigated the brain 5-HT(4) receptor [(3)H]SB207145 binding in the Flinders Sensitive Line rat depression model by quantitative receptor autoradiography....... In the Flinders Sensitive Line, the 5-HT(4) receptor and 5-HT transporter binding were decreased in the dorsal and ventral hippocampus, and the changes in binding were directly correlated within the dorsal hippocampus. Chronic but not acute paroxetine administration caused a 16-47% down-regulation of 5-HT(4......) receptor binding in all regions evaluated including the basal ganglia and hippocampus, while 5-HT depletion increased the 5-HT(4) receptor binding in the dorsal hippocampus, hypothalamus, and lateral globus pallidus. In comparison, the 5-HT(2A) receptor binding was decreased in the frontal and cingulate...
Martens-Mantai, Tanja; Speckmann, Erwin-Josef; Gorji, Ali
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.
Fonnum, F; Walaas, I
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.
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)
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.)
Lee, Ho Yun; Kim, Jae Hyoung; Weon, Young-Cheol; Youn, Sung Won; Kim, Sung Hyun; Lee, Jung Seok; Kim, Sang Yun
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.)
Yassa, Michael A; Reagh, Zachariah M
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.
probed by LABOCA, and by a factor of ≳ 1.5 for the SABOCA filament. Conclusions: Our data strongly suggest that the IRDC G304.74 has undergone hierarchical fragmentation. On the scale where the clumps have fragmented into cores, the process can be explained in terms of gravitational Jeans instability. Besides the filament being fragmented, the finding of embedded YSOs in G304.74 indicates its thermally supercritical state, although the potential non-thermal (turbulent) motions can render the cloud a virial equilibrium system on scale traced by LABOCA. The IRDC G304.74 has a seahorse-like morphology in the Herschel images, and the filament appears to be attached by elongated, perpendicular striations. This is potentially evidence that G304.74 is still accreting mass from the surrounding medium, and the accretion process can contribute to the dynamical evolution of the main filament. One of the clumps in G304.74, IRAS 13039-6108, is already known to be associated with high-mass star formation, but the remaining clumps and cores in this filament might preferentially form low and intermediate-mass stars owing to their mass reservoirs and sizes. Besides the presence of perpendicularly oriented, dusty striations and potential embedded intermediate-mass YSOs, G304.74 is a relatively nearby (d 2.5 kpc) IRDC, which makes it a useful target for future star formation studies. Owing to its observed morphology, we propose that G304.74 could be nicknamed the Seahorse Nebula. This publication is based on data acquired with the Atacama Pathfinder EXperiment (APEX) under programmes 083.F-9302(A) and 089.F-9310(A). APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory.The SABOCA and LABOCA maps shown in Fig. 1 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A123
Kutlu, Munir Gunes; Gould, Thomas J
It has long been hypothesized that conditioning mechanisms play major roles in addiction. Specifically, the associations between rewarding properties of drugs of abuse and the drug context can contribute to future use and facilitate the transition from initial drug use into drug dependency. On the other hand, the self-medication hypothesis of drug abuse suggests that negative consequences of drug withdrawal result in relapse to drug use as an attempt to alleviate the negative symptoms. In this review, we explored these hypotheses and the involvement of the hippocampus in the development and maintenance of addiction to widely abused drugs such as cocaine, amphetamine, nicotine, alcohol, opiates, and cannabis. Studies suggest that initial exposure to stimulants (i.e., cocaine, nicotine, and amphetamine) and alcohol may enhance hippocampal function and, therefore, the formation of augmented drug-context associations that contribute to the development of addiction. In line with the self-medication hypothesis, withdrawal from stimulants, ethanol, and cannabis results in hippocampus-dependent learning and memory deficits, which suggest that an attempt to alleviate these deficits may contribute to relapse to drug use and maintenance of addiction. Interestingly, opiate withdrawal leads to enhancement of hippocampus-dependent learning and memory. Given that a conditioned aversion to drug context develops during opiate withdrawal, the cognitive enhancement in this case may result in the formation of an augmented association between withdrawal-induced aversion and withdrawal context. Therefore, individuals with opiate addiction may return to opiate use to avoid aversive symptoms triggered by the withdrawal context. Overall, the systematic examination of the role of the hippocampus in drug addiction may help to formulate a better understanding of addiction and underlying neural substrates. © 2016 Kutlu and Gould; Published by Cold Spring Harbor Laboratory Press.
Kutlu, Munir Gunes
It has long been hypothesized that conditioning mechanisms play major roles in addiction. Specifically, the associations between rewarding properties of drugs of abuse and the drug context can contribute to future use and facilitate the transition from initial drug use into drug dependency. On the other hand, the self-medication hypothesis of drug abuse suggests that negative consequences of drug withdrawal result in relapse to drug use as an attempt to alleviate the negative symptoms. In this review, we explored these hypotheses and the involvement of the hippocampus in the development and maintenance of addiction to widely abused drugs such as cocaine, amphetamine, nicotine, alcohol, opiates, and cannabis. Studies suggest that initial exposure to stimulants (i.e., cocaine, nicotine, and amphetamine) and alcohol may enhance hippocampal function and, therefore, the formation of augmented drug-context associations that contribute to the development of addiction. In line with the self-medication hypothesis, withdrawal from stimulants, ethanol, and cannabis results in hippocampus-dependent learning and memory deficits, which suggest that an attempt to alleviate these deficits may contribute to relapse to drug use and maintenance of addiction. Interestingly, opiate withdrawal leads to enhancement of hippocampus-dependent learning and memory. Given that a conditioned aversion to drug context develops during opiate withdrawal, the cognitive enhancement in this case may result in the formation of an augmented association between withdrawal-induced aversion and withdrawal context. Therefore, individuals with opiate addiction may return to opiate use to avoid aversive symptoms triggered by the withdrawal context. Overall, the systematic examination of the role of the hippocampus in drug addiction may help to formulate a better understanding of addiction and underlying neural substrates. PMID:27634143
Maejima, Hiroshi; Kanemura, Naohiko; Kokubun, Takanori; Murata, Kenji; Takayanagi, Kiyomi
Aerobic exercise is known to increase expression of neurotrophins, particularly brain-derived neurotrophic factor (BDNF), in the hippocampus and to improve cognitive function. Exercise exerts neuroprotective effects in the hippocampus by inducing epigenetic changes, which play crucial roles in aging and neurodegenerative diseases. Specifically, the activity levels of histone acetyltransferases (HATs) and histone deacetylases (HDACs) regulate histone acetylation and modulate gene transcription. The objective of the present study was to assess the interactive effects of exercise and aging on cognitive function, expression of neurotrophins (BDNF and neurotrophin-4) and their receptors (tyrosine receptor kinase B and p75), and epigenetic regulations, including the activity of HATs and HADCs in the hippocampus. We used the senescence-accelerated mouse (SAM) model, specifically 13-month-old SAM resistant 1(SAMR1) and SAM prone 1 (SAMP1) lines. Mice were distributed into four groups based on accelerated senescence and exercise status. Mice in the exercise groups exercised on a treadmill for approximately 60min a day, 5days a week. Aerobic exercise for 4 weeks improved cognitive function, accompanied by an increase in BDNF expression and a decrease in p75 transcription in both SAMR1 and SAMP1. In addition, the exercise regimen activated both HAT and HDAC in the hippocampus. Therefore, the present study reveals that despite accelerated senescence, long-term exercise improved cognitive function, upregulated the expression of BDNF, and downregulated p75, a receptor involved in apoptotic signaling. Furthermore, long-term exercise enhanced activity of both HAT and HDAC, which may contribute to the transcriptional regulation underlying the improvement of cognitive function. Copyright © 2017 Elsevier B.V. All rights reserved.
Lötjönen, Jyrki; Wolz, Robin; Koikkalainen, Juha
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...
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
Full Text Available In this work, serial production lines with finished goods buffers operating in the pull regime are considered. The machines are assumed to obey Bernoulli reliability model. The problem of satisfying customers demand is addressed. The level of demand satisfaction is quantified by the due-time performance (DTP, which is defined as the probability to ship to the customer a required number of parts during a fixed time interval. Within this scenario, the definitions of DTP bottlenecks are introduced and a method for their identification is developed.
This book deals with line facilities. The contents of this book are outline line of wire telecommunication ; development of line, classification of section of line and theory of transmission of line, cable line ; structure of line, line of cable in town, line out of town, domestic cable and other lines, Optical communication ; line of optical cable, transmission method, measurement of optical communication and cable of the sea bottom, Equipment of telecommunication line ; telecommunication line facilities and telecommunication of public works, construction of cable line and maintenance and Regulation of line equipment ; regulation on technique, construction and maintenance.
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
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.
Gorbach, Tetiana; Pudas, Sara; Lundquist, Anders; Orädd, Greger; Josefsson, Maria; Salami, Alireza; de Luna, Xavier; Nyberg, Lars
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.
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.
Creese, I.; Snyder, S.H.
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.)
Watanabe, Takamitsu; Yagishita, Sho; Kikyo, Hideyuki
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.
Misane, I.; Tovote, P.; Meyer, M.; Spiess, J.; Ögren, S.O.; Stiedl, O.
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
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...
Jiang, Lizhu; Mao, Rongrong; Zhou, Qixin; Yang, Yuexiong; Cao, Jun; Ding, Yuqiang; Yang, Yuan; Zhang, Xia; Li, Lingjiang; Xu, Lin
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.
Fatranska, M.; Budai, D.; Gulya, K; Kvetnansky, R.
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
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.
Xia Jun; Zhou Yicheng; Zhang Jingfeng; Yang Bo; Xia Liming; Wang Chengyuan; Chen Jun
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)
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.
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
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...
Zhang, Wangxin; Zhang, Quiling; Deng, Wen; Li, Yalu; Xing, Guoqing; Shi, Xinjun; Du, Yifeng
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
James G. Worner
Full Text Available James Worner is an Australian-based writer and scholar currently pursuing a PhD at the University of Technology Sydney. His research seeks to expose masculinities lost in the shadow of Australia’s Anzac hegemony while exploring new opportunities for contemporary historiography. He is the recipient of the Doctoral Scholarship in Historical Consciousness at the university’s Australian Centre of Public History and will be hosted by the University of Bologna during 2017 on a doctoral research writing scholarship. ‘Parallel Lines’ is one of a collection of stories, The Shapes of Us, exploring liminal spaces of modern life: class, gender, sexuality, race, religion and education. It looks at lives, like lines, that do not meet but which travel in proximity, simultaneously attracted and repelled. James’ short stories have been published in various journals and anthologies.
Jornada, Luciano K.; Valvassori, Samira S.; Resende, Wilson R.; Moretti, Morgana; Ferreira, Camila L.; Fries, Gabriel R.; Kapczinski, Flavio; Quevedo, João
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...
Fisher, S.K.; Frey, K.A.; Agranoff, B.W.
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
Varela, Carmen; Weiss, Sarah; Meyer, Retsina; Halassa, Michael; Biedenkapp, Joseph; Wilson, Matthew A; Goosens, Ki Ann; Bendor, Daniel
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.
Pfluger, T; Weil, S; Weis, S; Vollmar, C; Heiss, D; Egger, J; Scheck, R; Hahn, K
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.
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.
Oliver Von Bohlen Und Halbach
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.
Galea, L A M; Wainwright, S R; Roes, M M; Duarte-Guterman, P; Chow, C; Hamson, D K
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.
Rosanna Kathleen Olsen
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.
Ho, Y C; Wang, S
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.
Greene Anthony J
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.
Sato, S.M.; Frazier, J.M.; Goldberg, A.M.
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
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.
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.
Kolata, Stefan M; Nakao, Kazuhito; Jeevakumar, Vivek; Farmer-Alroth, Emily L; Fujita, Yuko; Bartley, Aundrea F; Jiang, Sunny Zhihong; Rompala, Gregory R; Sorge, Robert E; Jimenez, Dennisse V; Martinowich, Keri; Mateo, Yolanda; Hashimoto, Kenji; Dobrunz, Lynn E; Nakazawa, Kazu
Whereas cortical GAD67 reduction and subsequent GABA level decrease are consistently observed in schizophrenia and depression, it remains unclear how these GABAergic abnormalities contribute to specific symptoms. We modeled cortical GAD67 reduction in mice, in which the Gad1 gene is genetically ablated from ~50% of cortical and hippocampal interneurons. Mutant mice showed a reduction of tissue GABA in the hippocampus and cortex including mPFC, and exhibited a cluster of effort-based behavior deficits including decreased home-cage wheel running and increased immobility in both tail suspension and forced swim tests. Since saccharine preference, progressive ratio responding to food, and learned helplessness task were normal, such avolition-like behavior could not be explained by anhedonia or behavioral despair. In line with the prevailing view that dopamine in anterior cingulate cortex (ACC) plays a role in evaluating effort cost for engaging in actions, we found that tail-suspension triggered dopamine release in ACC of controls, which was severely attenuated in the mutant mice. Conversely, ACC dopamine release by progressive ratio responding to reward, during which animals were allowed to effortlessly perform the nose-poking, was not affected in mutants. These results suggest that cortical GABA reduction preferentially impairs the effort-based behavior which requires much effort with little benefit, through a deficit of ACC dopamine release triggered by high-effort cost behavior, but not by reward-seeking behavior. Collectively, a subset of negative symptoms with a reduced willingness to expend costly effort, often observed in patients with schizophrenia and depression, may be attributed to cortical GABA level reduction.
Micale, Vincenzo; Stepan, Jens; Jurik, Angela; Pamplona, Fabricio A; Marsch, Rudolph; Drago, Filippo; Eder, Matthias; Wotjak, Carsten T
The development of exaggerated avoidance behavior is largely responsible for the decreased quality of life in patients suffering from anxiety disorders. Studies using animal models have contributed to the understanding of the neural mechanisms underlying the acquisition of avoidance responses. However, much less is known about its extinction. Here we provide evidence in mice that learning about the safety of an environment (i.e., safety learning) rather than repeated execution of the avoided response in absence of negative consequences (i.e., response extinction) allowed the animals to overcome their avoidance behavior in a step-down avoidance task. This process was context-dependent and could be blocked by pharmacological (3 mg/kg, s.c.; SR141716) or genetic (lack of cannabinoid CB1 receptors in neurons expressing dopamine D1 receptors) inactivation of CB1 receptors. In turn, the endocannabinoid reuptake inhibitor AM404 (3 mg/kg, i.p.) facilitated safety learning in a CB1-dependent manner and attenuated the relapse of avoidance behavior 28 days after conditioning. Safety learning crucially depended on endocannabinoid signaling at level of the hippocampus, since intrahippocampal SR141716 treatment impaired, whereas AM404 facilitated safety learning. Other than AM404, treatment with diazepam (1 mg/kg, i.p.) impaired safety learning. Drug effects on behavior were directly mirrored by drug effects on evoked activity propagation through the hippocampal trisynaptic circuit in brain slices: As revealed by voltage-sensitive dye imaging, diazepam impaired whereas AM404 facilitated activity propagation to CA1 in a CB1-dependent manner. In line with this, systemic AM404 enhanced safety learning-induced expression of Egr1 at level of CA1. Together, our data render it likely that AM404 promotes safety learning by enhancing information flow through the trisynaptic circuit to CA1. Copyright © 2017 Elsevier Ltd. All rights reserved.
Yang Bo; Zhou Yicheng; Xia Jun; Xia Liming; Wang Chengyuan
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)
Full Text Available The nicotinic acetylcholine receptor alpha2 subunit (Chrna2 is a specific marker for oriens lacunosum-moleculare (OLM interneurons in the dorsal CA1 region of the hippocampus. It was recently shown using a Chrna2-cre mice line that OLM interneurons can modulate entorhinal cortex and CA3 inputs and may therefore have an important role in gating, encoding, and recall of memory. In this study, we have used a combination of electrophysiology and optogenetics using Chrna2-cre mice to determine the role of Chrna2 interneurons in the subiculum area, the main output region of the hippocampus. We aimed to assess the similarities between Chrna2 subiculum and CA1 neurons in terms of the expression of interneuron markers, their membrane properties, and their inhibitory input to pyramidal neurons. We found that subiculum and CA1 dorsal Chrna2 cells similarly expressed the marker somatostatin and had comparable membrane and firing properties. The somas of Chrna2 cells in both regions were found in the deepest layer with axons projecting superficially. However, subiculum Chrna2 cells displayed more extensive projections with dendrites which occupied a significantly larger area than in CA1. The post-synaptic responses elicited by Chrna2 cells in pyramidal cells of both regions revealed comparable inhibitory responses elicited by GABAA receptors and, interestingly, GABAB receptor mediated components. This study provides the first in-depth characterization of Chrna2 cells in the subiculum, and suggests that subiculum and CA1 Chrna2 cells are generally similar and may play comparable roles in both sub-regions.
Judith M. Reichel
Full Text Available GABAergic interneurons are essential for a functional equilibrium between excitatory and inhibitory impulses throughout the CNS. Disruption of this equilibrium can lead to various neurological or neuropsychiatric disorders such as epileptic seizures or schizophrenia. Schizophrenia itself is clinically defined by negative- (e.g. depression and positive- (e.g. hallucinations symptoms as well as cognitive dysfunction. GABAergic interneurons are proposed to play a central role in the etiology and progression of schizophrenia; however, the specific mechanisms and the time-line of symptom development as well as the distinct involvement of cortical and hippocampal GABAergic interneurons in the etiology of schizophrenia-related symptoms are still not conclusively resolved.Previous work demonstrated that GABAergic interneurons can be selectively depleted in adult mice by means of saporin-conjugated anti-vesicular GABA transporter antibodies (SAVAs in vitro and in vivo. Given their involvement in Schizophrenia-related disease etiology, we ablated GABAergic interneurons in the medial prefrontal cortex (mPFC and dorsal hippocampus (dHPC in adult male C57BL/6N mice. Subsequently we assessed alterations in anxiety, sensory processing, hyperactivity and cognition after long-term (>14 days and short-term (< 14 days GABAergic depletion. Long-term GABAergic depletion in the mPFC resulted in a decrease in sensorimotor-gating and impairments in cognitive flexibility. Notably, the same treatment at the level of the dHPC completely abolished spatial learning capabilities. Short-term GABAergic depletion in the dHPC revealed a transient hyperactive phenotype as well as marked impairments regarding the acquisition of a spatial memory. In contrast, recall of a spatial memory was not affected by the same intervention. These findings emphasize the importance of functional local GABAergic networks for the encoding but not the recall of hippocampus-dependent spatial memories.
Vermont Center for Geographic Information — (Link to Metadata) This datalayer is comprised of Miscellaineous Transmission Lines. Digital line graph (DLG) data are digital representations of cartographic...
Schumacher, Anett; Vlassov, Ekaterina; Ito, Rutsuko
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.
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.
Galinato, Melissa H.; Orio, Laura; Mandyam, Chitra D.
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
Adachi, Michito; Ohshima, Fumi; Kawanami, Toru; Kawakatsu, Shinobu; Shibata, Akiko
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)
Nobakht, Maliheh; Hoseini, Seyed Mohammad; Mortazavi, Pejman; Sohrabi, Iraj; Esmailzade, Banafshe; Roosh, Nahid Rahbar; Omidzahir, Shila
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
Nobakht, Maliheh; Hoseini, Seyed Mohammad; Mortazavi, Pejman; Sohrabi, Iraj; Esmailzade, Banafshe; Rahbar Rooshandel, Nahid; Omidzahir, Shila
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.
Chen, Qian; Xiao, De-Sheng
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.
Miltenburg, G.J.; Wijngaard, J.
The traditional line balancing (LB) problem considers a production line in which stations are arranged consecutively in a line. A balance is determined by grouping tasks into stations while moving forward (or backward) through a precedence network. Recently many production lines are being arranged
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
Elfman, Kane W; Aly, Mariam; Yonelinas, Andrew P
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.
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.
Esmaeilzadeh, Mohammad; Soltanian-Zadeh, Hamid; Jafari-Khouzani, Kourosh
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.
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.
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.
Haahr, Mette Ewers; Fisher, Patrick; Holst, Klaus Kähler
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...
Goldfarb, Elizabeth V; Chun, Marvin M; Phelps, Elizabeth A
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.
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.
Sandoval-Salazar, Cuauhtemoc; Ramírez-Emiliano, Joel; Trejo-Bahena, Aurora; Oviedo-Solís, Cecilia I; Solís-Ortiz, Martha Silvia
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.
Neves, Guilherme; Cooke, Sam F; Bliss, Tim V P
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.
Killgore, William D. S.; Olson, Elizabeth A.; Weber, Mareen
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.
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.
Barbeau, Emmanuel J; Chauvel, Patrick; Moulin, Christopher J A; Regis, Jean; Liégeois-Chauvel, Catherine
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.
Mahadevan, Anand; Sampson, Carrie; LaRosa, Salvatore; Floyd, Scott R.; Wong, Eric T.; Uhlmann, Erik J.; Sengupta, Soma; Kasper, Ekkehard M.
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
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.
Fisher, S.K.; Boast, C.A.; Agranoff, B.W.
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.)
Bowman, Caitlin R; Zeithamova, Dagmar
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
Nickel, Kathrin; Tebartz van Elst, Ludger; Perlov, Evgeniy; Jitten-Schachenmeier, Renate; Beier, Daniel; Endres, Dominique; Goll, Peter; Philipsen, Alexandra; Maier, Simon
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.
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
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
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…
The occurrence, distribution and abundance of the endangered Knysna seahorse Hippocampus capensis in 10 estuaries on South Africa's warm temperate south coast, were investigated. Seahorses were found only in the Knysna, Swartvlei and Keurbooms estuaries. Sex ratios were even and, in most cases, more adults ...
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.
Rojas, Donald C; Smith, J Allegra; Benkers, Tara L; Camou, Suzanne L; Reite, Martin L; Rogers, Sally J
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.
Yu, Yan; Zeng, Changchun; Shu, Siyun; Liu, Xuemei; Li, Chuhua
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
Azuma, Kagaku; Zhou, Qian; Niwa, Masami; Kubo, Kin-Ya
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.
Kaiser, M.; Mareš, Vladislav; Šťastný, František; Bubeníková-Valešová, V.; Lisá, Věra; Suchomel, P.; Balcar, V. J.
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
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.
Hundahl, Christian Ansgar; Elfving, Betina; Müller, Heidi Kaastrup
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...
Acosta, Gabriela Beatriz; Fernández, María Alejandra; Roselló, Diego Martín; Tomaro, María Luján; Balestrasse, Karina; Lemberg, Abraham
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
Elekes, O; Venema, K; Postema, F; Dringen, R; Hamprecht, B; Korf, J
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
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.
JAARSMA, D; SEBENS, JB; KORF, J
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
Luciano K. Jornada
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.
Kjaerby, Celia; Hovelsø, Nanna; Dalby, Nils Ole; Sotty, Florence
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.
Zhao Li; Peng Ruiyun; Gao Yabing; Wang Shuiming; Wang Lifeng; Dong Qi; Xu Xinping; Ma Junjie
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)
Rachael D Rubin
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.
Baddeley, Alan; Allen, Richard; Vargha-Khadem, Faraneh
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…
Rubin, Rachael D; Watson, Patrick D; Duff, Melissa C; Cohen, Neal J
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.
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.
Mennini, T.; Miari, A.
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
P S Santos
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.
Brust, P; Christensen, Thomas; Diemer, Nils Henrik
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...
Hylin, Michael J.; Orsi, Sara A.; Moore, Anthony N.; Dash, Pramod K.
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…
Hales, Jena B.; Broadbent, Nicola J.; Velu, Priya D.; Squire, Larry R.; Clark, Robert E.
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…
Asano, Tetsuichi; Hanyu, Haruo
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)
Carmichael, O.; Xie, J.; Fletcher, E.; Singh, B.; DeCarli, C.; Olde Rikkert, M.; et al.,
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
Anděrová, Miroslava; Pivoňková, Helena; Benešová, Jana; Butenko, Olena; Chvátal, Alexandr
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
Yang, Juan; Hu, Lili; Wu, Qiuhua; Liu, Liying; Zhao, Lingyu; Zhao, Xiaoge; Song, Tusheng; Huang, Chen
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.
Valen, Eivind; Pascarella, Giovanni; Chalk, Alistair
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...
Ježek, Karel; Henriksen, E. J.; Treves, A.; Moser, E. I.; Moser, M.B.
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
Segev, Amir; Akirav, Irit
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.…
Wesierska, M.; Dockery, Colleen; Fenton, André Antonio
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
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
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
van der Zee, E.A.; Luiten, P.G.M.
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
Kibler, Andrew B; Durand, Dominique M
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.
Murtuza, Mohammad I; Isokawa, Masako
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.
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.
Leishman, D J; Boeijinga, P H; Galvan, M
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.
Jang, Hak Sin; Kim, Sin Yeong
This book is about cable line engineering. It is comprised of nine chapters, which deals with summary of cable communication such as way, process of cable communication and optical communication, Line constant of transmission on primary constant, reflection and crosstalk, communication cable line of types like flat cable, coaxial cable and loaded cable, Install of communication line with types and facility of aerial line, construction method of communication line facility, Measurement of communication line, Carrier communication of summary, PCM communication with Introduction, regeneration relay system sampling and quantization and Electric communication service and general information network with mobile communication technique and satellite communication system.
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.
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
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.
Motti, Dario; Le Duigou, Caroline; Eugène, Emmanuel
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...
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
Ježek, Karel; Wesierska, M.; Fenton, André Antonio
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
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.)
Kozareva, Danka A; Hueston, Cara M; Ó'Léime, Ciarán S; Crotty, Suzanne; Dockery, Peter; Cryan, John F; Nolan, Yvonne M
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.
Carasatorre, M; Ramírez-Amaya, V; Díaz Cintra, S
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.
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
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.
Hundahl, Christian Ansgar; Fahrenkrug, Jan; Hannibal, Jens
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...
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.
Regina A. Weilbächer
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.
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.
Sakaguchi, Yukitoshi; Sakurai, Yoshio
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.
Chiapponi, Chiara; Piras, Fabrizio; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco
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.
Frederickson, C.J.; Klitenick, M.A.; Manton, W.I.; Kirkpatrick, J.B.
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.)
Wei, Guo; Hough, Christopher J; Sarvey, John M
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.
Keleta, Yonas B; Martinez, Joe L
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.
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
Akirav, Irit; Richter-Levin, Gal
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...
Vivekanandarajah, Arunnjah; Aishah, Atqiya; Waters, Karen A; Machaalani, Rita
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.
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.
Yu De; Tian Ye; Ding Weijun; Zhu Yaqun; Liu Chunfeng
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)
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...
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...
Bjorvatn, B; Grønli, J; Hamre, F; Sørensen, E; Fiske, E; Bjorkum, Alvhild Alette; Portas, CM; Ursin, R
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...
Tan, Anh; Ma, Wenli; Vira, Amit; Marwha, Dhruv; Eliot, Lise
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.
Hoshida, Tohru; Sakaki, Toshisuke; Uematsu, Sumio.
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.)
Marquet-de Rougé, Perrine; Clamagirand, Christine; Facchinetti, Patricia; Rose, Christiane; Sargueil, Françoise; Guihenneuc-Jouyaux, Chantal; Cynober, Luc; Moinard, Christophe; Allinquant, Bernadette
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.
Manchev, L.; Toneva, J.; Manolova, T.; Manchev, I.; Valcheva, V.
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
Biegler, Robert; McGregor, Anthony; Krebs, John R.; Healy, Susan D.
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...
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
Shi, Yulin; Ikrar, Taruna; Olivas, Nicholas D; Xu, Xiangmin
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.
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.
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
Ross, Robert S.; LoPresti, Matthew L.; Schon, Karin; Stern, Chantal E.
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
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: email@example.com [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan)
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.
Sourial, Mary; Doering, Laurie C
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.
Sutherland, R J; Lehmann, H
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.
Sayyed Alireza Talaei
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.
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.
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...
Uekita, Tomoko; Okanoya, Kazuo
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.
John I. Broussard
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.
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.
Lukas M. von Ziegler
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
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.
Baddeley, Alan; Allen, Richard; Vargha-Khadem, Faraneh
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.
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.
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.
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.
Lee, S.K.; Kim, D.W.; Kim, K.K.; Chung, C.K.; Song, I.C.; Chang, K.H.
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.)
McNaughton, Neil; Wickens, Jeff
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.
Jiang, Lizhu; Mao, Rongrong; Tong, Jianbin; Li, Jinnan; Chai, Anping; Zhou, Qixin; Yang, Yuexiong; Wang, Liping; Li, Lingjiang; Xu, Lin
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.
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)
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.)
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.
Daskalakis, Nikolaos P.; De Kloet, Edo Ronald; Yehuda, Rachel; Malaspina, Dolores; Kranz, Thorsten M.
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
Nikolaos P Daskalakis
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.
DeMaster, Dana; Pathman, Thanujeni; Lee, Joshua K; Ghetti, Simona
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: firstname.lastname@example.org.
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.
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
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.
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.
Addante, Richard James
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
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.
Chen Shulin; Li Lingjiang; Zhang Jinlin; Ma Ning; Gao Xueping; Liu Jun; He Zhong
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)
Ayuob, Nasra Naeim; El Wahab, Manal Galal Abd; Ali, Soad Shaker; Abdel-Tawab, Hanem Saad
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.
Canales, Juan J
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.
Connor, David A; Kutlu, Munir G; Gould, Thomas J
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.
Ozen, Ilknur; Galichet, Christophe; Watts, Colin; Parras, Carlos; Guillemot, François; Raineteau, Olivier
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.
Patel, Sita Sharan; Parashar, Arun; Udayabanu, Malairaman
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.
Bliss-Moreau, Eliza; Moadab, Gilda; Santistevan, Anthony; Amaral, David G
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.
André, Marion Agnès Emma; Manahan-Vaughan, Denise
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.
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
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.