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Sample records for cortical spreading depression

  1. Vagus nerve stimulation inhibits cortical spreading depression.

    Science.gov (United States)

    Chen, Shih-Pin; Ay, Ilknur; de Morais, Andreia Lopes; Qin, Tao; Zheng, Yi; Sadeghian, Homa; Oka, Fumiaki; Simon, Bruce; Eikermann-Haerter, Katharina; Ayata, Cenk

    2016-04-01

    Vagus nerve stimulation has recently been reported to improve symptoms of migraine. Cortical spreading depression is the electrophysiological event underlying migraine aura and is a trigger for headache. We tested whether vagus nerve stimulation inhibits cortical spreading depression to explain its antimigraine effect. Unilateral vagus nerve stimulation was delivered either noninvasively through the skin or directly by electrodes placed around the nerve. Systemic physiology was monitored throughout the study. Both noninvasive transcutaneous and invasive direct vagus nerve stimulations significantly suppressed spreading depression susceptibility in the occipital cortex in rats. The electrical stimulation threshold to evoke a spreading depression was elevated by more than 2-fold, the frequency of spreading depressions during continuous topical 1 M KCl was reduced by ∼40%, and propagation speed of spreading depression was reduced by ∼15%. This effect developed within 30 minutes after vagus nerve stimulation and persisted for more than 3 hours. Noninvasive transcutaneous vagus nerve stimulation was as efficacious as direct invasive vagus nerve stimulation, and the efficacy did not differ between the ipsilateral and contralateral hemispheres. Our findings provide a potential mechanism by which vagus nerve stimulation may be efficacious in migraine and suggest that susceptibility to spreading depression is a suitable platform to optimize its efficacy.

  2. Cortical spreading depression impairs oxygen delivery and metabolism in mice.

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    Yuzawa, Izumi; Sakadžić, Sava; Srinivasan, Vivek J; Shin, Hwa Kyoung; Eikermann-Haerter, Katharina; Boas, David A; Ayata, Cenk

    2012-02-01

    Cortical spreading depression (CSD) is associated with severe hypoperfusion in mice. Using minimally invasive multimodal optical imaging, we show that severe flow reductions during and after spreading depression are associated with a steep decline in cerebral metabolic rate of oxygen. Concurrent severe hemoglobin desaturation suggests that the oxygen metabolism becomes at least in part supply limited, and the decrease in cortical blood volume implicates vasoconstriction as the mechanism. In support of oxygen supply-demand mismatch, cortical nicotinamide adenine dinucleotide (NADH) fluorescence increases during spreading depression for at least 5 minutes, particularly away from parenchymal arterioles. However, modeling of tissue oxygen delivery shows that cerebral metabolic rate of oxygen drops more than predicted by a purely supply-limited model, raising the possibility of a concurrent reduction in oxygen demand during spreading depression. Importantly, a subsequent spreading depression triggered within 15 minutes evokes a monophasic flow increase superimposed on the oligemic baseline, which markedly differs from the response to the preceding spreading depression triggered in naive cortex. Altogether, these data suggest that CSD is associated with long-lasting oxygen supply-demand mismatch linked to severe vasoconstriction in mice.

  3. Cortical spreading depression-induced preconditioning in the brain

    Institute of Scientific and Technical Information of China (English)

    Ping-ping Shen; Shuai Hou; Di Ma; Ming-ming Zhao; Ming-qin Zhu; Jing-dian Zhang; Liang-shu Feng; Li Cui; Jia-chun Feng

    2016-01-01

    Cortical spreading depression is a technique used to depolarize neurons. During focal or global ischemia, cortical spreading depression-induced preconditioning can enhance tolerance of further injury. Howev-er, the underlying mechanism for this phenomenon remains relatively unclear. To date, numerous issues exist regarding the experimental model used to precondition the brain with cortical spreading depression, such as the administration route, concentration of potassium chloride, induction time, duration of the protection provided by the treatment, the regional distribution of the protective effect, and the types of neurons responsible for the greater tolerance. In this review, we focus on the mechanisms underlying cor-tical spreading depression-induced tolerance in the brain, considering excitatory neurotransmission and metabolism, nitric oxide, genomic reprogramming, inlfammation, neurotropic factors, and cellular stress response. Speciifcally, we clarify the procedures and detailed information regarding cortical spreading de-pression-induced preconditioning and build a foundation for more comprehensive investigations in the ifeld of neural regeneration and clinical application in the future.

  4. Cortical spreading depression in migraine-time to reconsider?

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    Alan J McComas

    2015-08-01

    Full Text Available New evidence concerning the pathophysiology of migraine has come from the results of therapeutic transcranial magnetic stimulation (tTMS. The instantaneous responses to single pulses applied during the aura or headache phase, together with a number of other observations, make it unlikely that cortical spreading depression is involved in migraine. tTMS is considered to act by abolishing abnormal impulse activity in cortical pyramidal neurons and a suggestion is made as to how this activity could arise.

  5. Neuroprotection and acidosis induced by cortical spreading depression

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    Kwong KK

    2016-12-01

    Full Text Available Kenneth K Kwong, Suk-tak Chan Department of Radiology, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA We read with interest the article “Cortical spreading depression produces a neuroprotective effect activating mitochondrial uncoupling protein-5” published in Neuropsychiatr Dis Treat by Viggiano et al.1 The authors showed that cerebral spreading depression (CSD triggered uncoupling protein-5 (UCP-5,1 which had been reported to exert a long-term effect upon neuron protection.2 The result is another piece in CSD literature on modifying gene expressions to provide neuroprotection to subsequent ischemic episodes.3,4 Authors' replyGiovanni Messina1,2Emanuela Viggiano1,3Vincenzo Monda1Antonietta Messina1Fiorenzo Moscatelli2Anna Valenzano2Domenico Tafuri4Vincenzo De Luca5Giuseppe Cibelli2Marcellino Monda1 1Section of Human Physiology and Unit of Dietetic and Sport Medicine, Department of Experimental Medicine, Second University of Naples, Caserta, 2Department of Clinical and Experimental Medicine, University of Foggia, Foggia, 3Department of Medicine, University of Padua, Padua, 4Department of Motor Sciences and Wellness, University of Naples “Parthenope,” Napoli, Italy; 5Department of Psychiatry, University of Toronto, Toronto, ON, Canada Thank you for the attention paid to our article entitled: “Cortical spreading depression produces a neuroprotective effect activating mitochondrial uncoupling protein-5”.1 We do agree that cerebral spreading depression (CSD-induced acidosis is an intriguing aspect of the neuroprotection puzzle. It is well known that CSD is involved in the pathophysiology of migraine, cerebral ischemia, subarachnoid hemorrhage, and traumatic brain injury.2–7 View the original paper by Viggiano and colleagues. 

  6. In vivo optical imaging of cortical spreading depression in rat

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    Chen, Shangbin; Li, Pengcheng; Luo, Weihua; Gong, Hui; Cheng, Haiying; Luo, Qingming

    2003-12-01

    Intrinsic optical signals imaging (IOSI) and laser speckle imaging (LSI) are both novel techniques for functional neuroimaging in vivo. Combining them to study cortical spreading depression (CSD) which is an important disease model for migraine and other neurological disorders. CSD were induced by pinprick in Sprague-Dawley rats. Intrinsic optical signals (IOS) at 540 nm showed CSD evolution happened in one hemisphere cortex at speeds of 3.7+/-0.4 mm/min, and the vasodilation closely correlated a four-phasic response. By LSI, we observed a transient and significant increase cerebral blood flow (CBF). In this paper, optical imaging would be showed as a powerful tool for describing the hemodynamic character during CSD in rat.

  7. Cortical spreading depression occurs during elective neurosurgical procedures.

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    Carlson, Andrew P; William Shuttleworth, C; Mead, Brittany; Burlbaw, Brittany; Krasberg, Mark; Yonas, Howard

    2017-01-01

    OBJECTIVE Cortical spreading depression (CSD) has been observed with relatively high frequency in the period following human brain injury, including traumatic brain injury and ischemic/hemorrhagic stroke. These events are characterized by loss of ionic gradients through massive cellular depolarization, neuronal dysfunction (depression of electrocorticographic [ECoG] activity) and slow spread (2-5 mm/min) across the cortical surface. Previous data obtained in animals have suggested that even in the absence of underlying injury, neurosurgical manipulation can induce CSD and could potentially be a modifiable factor in neurosurgical injury. The authors report their initial experience with direct intraoperative ECoG monitoring for CSD. METHODS The authors prospectively enrolled patients undergoing elective craniotomy for supratentorial lesions in cases in which the surgical procedure was expected to last > 2 hours. These patients were monitored for CSD from the time of dural opening through the time of dural closure, using a standard 1 × 6 platinum electrode coupled with an AC or full-spectrum DC amplifier. The data were processed using standard techniques to evaluate for slow potential changes coupled with suppression of high-frequency ECoG propagating across the electrodes. Data were compared with CSD validated in previous intensive care unit (ICU) studies, to evaluate recording conditions most likely to permit CSD detection, and identify likely events during the course of neurosurgical procedures using standard criteria. RESULTS Eleven patients underwent ECoG monitoring during elective neurosurgical procedures. During the periods of monitoring, 2 definite CSDs were observed to occur in 1 patient and 8 suspicious events were detected in 4 patients. In other patients, either no events were observed or artifact limited interpretation of the data. The DC-coupled amplifier system represented an improvement in stability of data compared with AC-coupled systems. Compared

  8. Cerebral blood flow in migraine and cortical spreading depression

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    Lauritzen, M.

    1987-01-01

    In a series of migraine patients, carotid arteriography was carried out as part of the clinical evalution. Nine patients developed a migrainous attack with focal neurological symptoms and headache after the angiography and during the subsequent, ongoing regional cerebral blood flow rCBF study. rCBF was measured by bolus injection of Xenon/sup 133/ into the internal carotid artery and a gamma camera with 254 collimated scintillation detectors covering the lateral aspect of the hemisphere. This technique depicts rCBF mainly at the level of the superficial cortex, with no depth resolution. The resolution is 1 cm/sup 2/ providing detailed spatial information of the cortical blood flow. Other methods for measuring local blood flow in animal and man employ a radioactive, freely diffusible tracer, in combination with an autoradiographic technique for the assessment of the tissue concentration, the so-called autoradiographic methods. In the series of patients with spontaneous migraine, rCBF was estimated using an in-vivo application of the autoradiographic principle. Xenon/sup 133/ was administered by inhalation and the time course of the arterial concentration curve was assessed by a scintillation detector over the upper right lung, since the arterial curve has been found to follow the shape of the lung curve. The rCBF was studied accompanying cortical spreading depression in rat experiments to evaluate wheter this phenomenon could explain the blood flow changes in migraine. (/sup 14/C) iodoantipyrine was given as an intravenous bolus injection and the brain content of indicator was determined by tissue sample or autoradiography after 10 or 20 seconds of isotope circulation. The conditions of the autoradiographic methods are that the flow remains constant within the period of measuring, and that the region under study is homogenous with regard to flow and lambda. (EG).

  9. Mathematical approaches to modeling of cortical spreading depression

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    Miura, Robert M.; Huang, Huaxiong; Wylie, Jonathan J.

    2013-12-01

    Migraine with aura (MwA) is a debilitating disease that afflicts about 25%-30% of migraine sufferers. During MwA, a visual illusion propagates in the visual field, then disappears, and is followed by a sustained headache. MwA was conjectured by Lashley to be related to some neurological phenomenon. A few years later, Leão observed electrophysiological waves in the brain that are now known as cortical spreading depression (CSD). CSD waves were soon conjectured to be the neurological phenomenon underlying MwA that had been suggested by Lashley. However, the confirmation of the link between MwA and CSD was not made until 2001 by Hadjikhani et al. [Proc. Natl. Acad. Sci. U.S.A. 98, 4687-4692 (2001)] using functional MRI techniques. Despite the fact that CSD has been studied continuously since its discovery in 1944, our detailed understandings of the interactions between the mechanisms underlying CSD waves have remained elusive. The connection between MwA and CSD makes the understanding of CSD even more compelling and urgent. In addition to all of the information gleaned from the many experimental studies on CSD since its discovery, mathematical modeling studies provide a general and in some sense more precise alternative method for exploring a variety of mechanisms, which may be important to develop a comprehensive picture of the diverse mechanisms leading to CSD wave instigation and propagation. Some of the mechanisms that are believed to be important include ion diffusion, membrane ionic currents, osmotic effects, spatial buffering, neurotransmitter substances, gap junctions, metabolic pumps, and synaptic connections. Discrete and continuum models of CSD consist of coupled nonlinear differential equations for the ion concentrations. In this review of the current quantitative understanding of CSD, we focus on these modeling paradigms and various mechanisms that are felt to be important for CSD.

  10. PSD-95 uncoupling from NMDA receptors by Tat-N-dimer ameliorates neuronal depolarisation in cortical spreading depression

    DEFF Research Database (Denmark)

    Kucharz, Krzysztof; Søndergaard Rasmussen, Ida; Bach, Anders;

    2017-01-01

    of the negative shift in direct current potential by 33% (4.1 mV). Furthermore, the compound diminished the average depression of spontaneous electrocorticographic activity by 11% during first 40 min of post-cortical spreading depression recovery, but did not mitigate the suppressing effect of cortical spreading...... during the first hour after i.v. injection. The Tat-N-dimer suppressed stimulation-evoked synaptic activity by 2-20%, while cortical blood flow and cerebral oxygen metabolic (CMRO2) responses were preserved. During cortical spreading depression, the Tat-N-dimer reduced the average amplitude...

  11. Caffeine/nutrition interaction in the rat brain: Influence on latent inhibition and cortical spreading depression.

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    de Aguiar, Márlison José Lima; de Aguiar, Cilene Rejane Ramos Alves; Guedes, Rubem Carlos Araújo

    2011-01-10

    Caffeine, like malnutrition, can produce behavioral and electrophysiological alterations. However, the interaction of both factors remains unclear. Here this interaction has been studied in male Wistar rats previously malnourished during the lactation period by feeding their dams the "regional basic diet" of Northeast Brazil, containing about 8% protein, predominantly from vegetable sources (RBD(8)). At 70-75days of life, a subset of the pups was treated intraperitoneally with 30mg/kg caffeine for 4days while being tested according to the behavioral model of latent inhibition. Another group was subjected to an electrophysiological recording of the phenomenon known as cortical spreading depression, and the effects of caffeine injected during the recording session were evaluated. Caffeine did not affect cortical spreading depression, but antagonized latent inhibition in both the RBD(8)-malnourished rats and in the well-nourished control group fed a chow diet with 22% protein. This effect of caffeine was not seen in malnourished rats fed a protein-supplemented RBD (protein increased to 22% by increasing the proportion of foodstuffs from vegetable origin; RBD(22) group), suggesting that the amino acid imbalance of this diet may modulate the caffeine effects on latent inhibition. The results indicate a differential effect of caffeine in the latent inhibition behavioral model, as compared to the cortical spreading depression phenomenon, and this effect is influenced by the early nutritional status of the animal. We suggest that caffeine may modulate dopaminergic subcortical receptors participating in attention processes, but does not interact at the cortical level, in a way that would affect cortical spreading depression.

  12. Subcortical cerebral blood flow and metabolic changes elicited by cortical spreading depression in rat

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    Mraovitch, S.; Calando, Y.; Goadsby, P.J.; Seylaz, J. (Laboratoire de Recherches Cerebrovasculaire, Paris (France))

    1992-06-01

    Changes in cerebral cortical perfusion (CBF{sub LDF}), local cerebral blood flow (lCBF) and local cerebral glucose utilization (lCGU) elicited by unilateral cortical spreading depression (SD) were monitored and measured in separate groups of rats anesthetized with {alpha}-chloralose. CBF{sub LDF} was recorded with laser Doppler flowmetry, while lCBF and lCGU were measured by the quantitative autoradiographic ({sup 14}C)iodoantipyrine and ({sup 14}C)-2-deoxyglucose methods, respectively. SD elicited a wave of hyperemia after a latency of 2 to 3 min followed by an oligemic phase. Ninety minutes following the onset of SD cortical lCBF and lCGU were essentially the same as on the contralateral side and in sham-treated rats. However, alteration in the lCBF and lCGU in upper and lower brainstem persisted. The present results demonstrate that long-lasting cerebrovascular and metabolic alterations take place within the subcortical regions following SD. These regions provide an attractive site to integrate observations in man concerning spreading depression and the aura of migraine with the other features of the syndrome. 19 refs., 2 figs., 1 tab.

  13. Cortical spreading depression produces a neuroprotective effect activating mitochondrial uncoupling protein-5

    Directory of Open Access Journals (Sweden)

    Viggiano E

    2016-07-01

    Full Text Available Emanuela Viggiano,1,2 Vincenzo Monda,1 Antonietta Messina,1 Fiorenzo Moscatelli,3 Anna Valenzano,3 Domenico Tafuri,4 Giuseppe Cibelli,3 Bruno De Luca,1 Giovanni Messina,1,3 Marcellino Monda1 1Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetics and Sports Medicine, Second University of Naples, Naples, 2Department of Medicine, University of Padua, Padua, 3Department of Clinical and Experimental Medicine, University of Foggia, Foggia, 4Department of Motor Sciences and Wellness, University of Naples “Parthenope”, Naples, Italy Abstract: Depression of electrocorticogram propagating over the cortex surface results in cortical spreading depression (CSD, which is probably related to the pathophysiology of stroke, epilepsy, and migraine. However, preconditioning with CSD produces neuroprotection to subsequent ischemic episodes. Such effects require the expression or activation of several genes, including neuroprotective ones. Recently, it has been demonstrated that the expression of the uncoupling proteins (UCPs 2 and 5 is amplified during brain ischemia and their expression exerts a long-term effect upon neuron protection. To evaluate the neuroprotective consequence of CSD, the expression of UCP-5 in the brain cortex was measured following CSD induction. CSD was evoked in four samples of rats, which were sacrificed after 2 hours, 4 hours, 6 hours, and 24 hours. Western blot analyses were carried out to measure UCP-5 concentrations in the prefrontal cortices of both hemispheres, and immunohistochemistry was performed to determine the localization of UCP-5 in the brain cortex. The results showed a significant elevation in UCP-5 expression at 24 hours in all cortical strata. Moreover, UCP-5 was triggered by CSD, indicating that UCP-5 production can have a neuroprotective effect. Keywords: cortical spreading depression, neuroprotective effect, uncoupling protein-5

  14. History of migraine with aura and cortical spreading depression from 1941 and onwards

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    Tfelt-Hansen, P C

    2010-01-01

    visual cortex. Leão described cortical spreading depression (CSD) in rabbits in 1944 and noticed its similarity to the migraine aura. Despite these scattered pieces of evidence, the prevailing theory was that the migraine aura was caused by a vasospasm and cortical ischaemia. The advent of a technique...... borders of supply of major cerebral arteries. These observations refuted the ischaemic hypothesis. The human studies showed initial hyperaemia followed by prolonged hypoperfusion. The relation between aura and CSD was known to cause short-lasting, and therefore not obvious vasodilation...... expressed in mice and lower the threshold for CSD. The seminal papers on rCBF and CSD published in the 1980s caused a dramatic shift in our concepts of migraine aura. They moved attention from ischaemia to CSD and thereby to the brain itself, and paved the way for subsequent discoveries of brainstem...

  15. Changes in Mice Brain Spontaneous Electrical Activity during Cortical Spreading Depression due to Mobile Phone Radiation

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    Sallam, Samera M.; Mohamed, Ehab I.; Dawood, Abdel-Fattah B.

    2008-01-01

    The objective of the present study was to investigate changes in spontaneous EEG activity during cortical spreading depression (CSD) in mice brain. The cortical region of anaesthetized mice were exposed to the electromagnetic fields (EMFs) emitted from a mobile phone (MP, 935.2-960.2 MHz, 41.8 mW/cm2). The effect of EMFs on EEG was investigated before and after exposure to different stimuli (MP, 2% KCl, and MP & 2% KCl). The records of brain spontaneous EEG activity, slow potential changes (SPC), and spindle shaped firings were obtained through an interfaced computer. The results showed increases in the amplitude of evoked spindles by about 87%, 17%, and 226% for MP, 2% KCl, and MP & 2% KCl; respectively, as compared to values for the control group. These results showed that the evoked spindle is a more sensitive indicator of the effect of exposure to EMFs from MP. PMID:23675079

  16. Cortical spreading depression in traumatic brain injuries: is there a role for astrocytes?

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    Torrente, Daniel; Cabezas, Ricardo; Avila, Marco Fidel; García-Segura, Luis Miguel; Barreto, George E; Guedes, Rubem Carlos Araújo

    2014-04-17

    Cortical spreading depression (CSD) is a presumably pathophysiological phenomenon that interrupts local cortical function for periods of minutes to hours. This phenomenon is important due to its association with different neurological disorders such as migraine, malignant stroke and traumatic brain injury (TBI). Glial cells, especially astrocytes, play an important role in the regulation of CSD and in the protection of neurons under brain trauma. The correlation of TBI with CSD and the astrocytic function under these conditions remain unclear. This review discusses the possible link of TBI and CSD and its implication for neuronal survival. Additionally, we highlight the importance of astrocytic function for brain protection, and suggest possible therapeutic strategies targeting astrocytes to improve the outcome following TBI-associated CSD.

  17. PSD-95 uncoupling from NMDA receptors by Tat- N-dimer ameliorates neuronal depolarization in cortical spreading depression.

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    Kucharz, Krzysztof; Søndergaard Rasmussen, Ida; Bach, Anders; Strømgaard, Kristian; Lauritzen, Martin

    2017-05-01

    Cortical spreading depression is associated with activation of NMDA receptors, which interact with the postsynaptic density protein 95 (PSD-95) that binds to nitric oxide synthase (nNOS). Here, we tested whether inhibition of the nNOS/PSD-95/NMDA receptor complex formation by anti-ischemic compound, UCCB01-144 (Tat- N-dimer) ameliorates the persistent effects of cortical spreading depression on cortical function. Using in vivo two-photon microscopy in somatosensory cortex in mice, we show that fluorescently labelled Tat- N-dimer readily crosses blood-brain barrier and accumulates in nerve cells during the first hour after i.v. injection. The Tat- N-dimer suppressed stimulation-evoked synaptic activity by 2-20%, while cortical blood flow and cerebral oxygen metabolic (CMRO2) responses were preserved. During cortical spreading depression, the Tat- N-dimer reduced the average amplitude of the negative shift in direct current potential by 33% (4.1 mV). Furthermore, the compound diminished the average depression of spontaneous electrocorticographic activity by 11% during first 40 min of post-cortical spreading depression recovery, but did not mitigate the suppressing effect of cortical spreading depression on cortical blood flow and CMRO2. We suggest that uncoupling of PSD-95 from NMDA receptors reduces overall neuronal excitability and the amplitude of the spreading depolarization wave. These findings may be of interest for understanding the neuroprotective effects of the nNOS/PSD-95 uncoupling in stroke.

  18. Spatio-temporal cerebral blood flow perfusion patterns in cortical spreading depression

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    Verisokin, Andrey Yu.; Verveyko, Darya V.; Postnov, Dmitry E.

    2017-04-01

    Cortical spreading depression (CSD) is an example of one of the most common abnormalities in biophysical brain functioning. Despite the fact that there are many mathematical models describing the cortical spreading depression (CSD), most of them do not take into consideration the role of redistribution of cerebral blood flow (CBF), that results in the formation of spatio-temporal patterns. The paper presents a mathematical model, which successfully explains the CBD role in the CSD process. Numerical study of this model has revealed the formation of stationary dissipative structures, visually analogous to Turing structures. However, the mechanism of their formation is not diffusion. We show these structures occur due to another type of spatial coupling, that is related to tissue perfusion rate. The proposed model predicts that at similar state of neurons the distribution of blood flow and oxygenation may by different. Currently, this effect is not taken into account when the Blood oxygen-level dependent (BOLD) contrast imaging used in functional magnetic resonance imaging (fMRI). Thus, the diagnosis on the BOLD signal can be ambiguous. We believe that our results can be used in the future for a more correct interpretation of the data obtained with fMRI, NIRS and other similar methods for research of the brain activity.

  19. Poloxamer-188 and citicoline provide neuronal membrane integrity and protect membrane stability in cortical spreading depression.

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    Yıldırım, Timur; Eylen, Alpaslan; Lule, Sevda; Erdener, Sefik Evren; Vural, Atay; Karatas, Hulya; Ozveren, Mehmet Faik; Dalkara, Turgay; Gursoy-Ozdemir, Yasemin

    2015-01-01

    Under pathological conditions such as brain trauma, subarachnoid hemorrhage and stroke, cortical spreading depression (CSD) or peri-infarct depolarizations contribute to brain damage in animal models of neurological disorders as well as in human neurological diseases. CSD causes transient megachannel opening on the neuronal membrane, which may compromise neuronal survival under pathological conditions. Poloxamer-188 (P-188) and citicoline are neuroprotectants with membrane sealing properties. The aim of this study is to investigate the effect of P-188 and citicoline on the neuronal megachannel opening induced by CSD in the mouse brain. We have monitored megachannel opening with propidium iodide, a membrane impermeable fluorescent dye and, demonstrate that P-188 and citicoline strikingly decreased CSD-induced neuronal PI influx in cortex and hippocampal dentate gyrus. Therefore, these agents may be providing neuroprotection by blocking megachannel opening, which may be related to their membrane sealing action and warrant further investigation for treatment of traumatic brain injury and ischemic stroke.

  20. The effects of anesthetics on cortical spreading depression elicitation and c-fos expression in rats.

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    Kitahara, Y; Taga, K; Abe, H; Shimoji, K

    2001-01-01

    The effects of anesthetics on the generation of cortical spreading depression (CSD) were investigated. Volatile anesthetics halothane, isoflurane, sevoflurane (0.5, 1.0, and 2.0 MAC), and the intravenous anesthetic pentobarbital were studied. Cortical spreading depression was induced by 3M-KCl applied to a surface of brain cortex for 30 minutes. Direct current (DC) potential was recorded, and the number, amplitude, and duration of CSDs were observed. With increasing concentrations of each volatile anesthetic, there was a dose-related reduction in CSD frequency but not in CSD amplitude. At 2.0 MAC of sevoflurane the suppression of CSD was less than with the other volatile anesthetics. In addition, the influence of anesthetics on expression of c-fos mRNA was investigated. Additional animals anesthetized by isoflurane or sevoflurane were studied. Five CSDs were elicited by electric stimulation (0.5 mV, 1 second) in each animal. In situ hybridization with 35S-labeled oligonucleotides was used to evaluate the level of c-fos mRNA. The expression of c-fos was observed in the hemisphere in which CSD was elicited, but there was no difference in expression of c-fos among the groups. We conclude that volatile anesthetics can induce suppression of CSD elicitation in a dose dependent manner, but that at high concentrations sevoflurane is significantly less effective than other volatile agents. Pentobarbital has the least effect on KCl-induced CSD. These data suggest that the choice of anesthetics can impact the results of studies examining membrane depolarization and the ionic changes initiated by CSD.

  1. Cortical Spreading Depression Causes Unique Dysregulation of Inflammatory Pathways in a Transgenic Mouse Model of Migraine.

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    Eising, Else; Shyti, Reinald; 't Hoen, Peter A C; Vijfhuizen, Lisanne S; Huisman, Sjoerd M H; Broos, Ludo A M; Mahfouz, Ahmed; Reinders, Marcel J T; Ferrari, Michel D; Tolner, Else A; de Vries, Boukje; van den Maagdenberg, Arn M J M

    2017-05-01

    Familial hemiplegic migraine type 1 (FHM1) is a rare monogenic subtype of migraine with aura caused by mutations in CACNA1A that encodes the α1A subunit of voltage-gated CaV2.1 calcium channels. Transgenic knock-in mice that carry the human FHM1 R192Q missense mutation ('FHM1 R192Q mice') exhibit an increased susceptibility to cortical spreading depression (CSD), the mechanism underlying migraine aura. Here, we analysed gene expression profiles from isolated cortical tissue of FHM1 R192Q mice 24 h after experimentally induced CSD in order to identify molecular pathways affected by CSD. Gene expression profiles were generated using deep serial analysis of gene expression sequencing. Our data reveal a signature of inflammatory signalling upon CSD in the cortex of both mutant and wild-type mice. However, only in the brains of FHM1 R192Q mice specific genes are up-regulated in response to CSD that are implicated in interferon-related inflammatory signalling. Our findings show that CSD modulates inflammatory processes in both wild-type and mutant brains, but that an additional unique inflammatory signature becomes expressed after CSD in a relevant mouse model of migraine.

  2. Clinical relevance of cortical spreading depression in neurological disorders: migraine, malignant stroke, subarachnoid and intracranial hemorrhage, and traumatic brain injury

    DEFF Research Database (Denmark)

    Lauritzen, Martin; Dreier, Jens Peter; Fabricius, Martin

    2011-01-01

    Cortical spreading depression (CSD) and depolarization waves are associated with dramatic failure of brain ion homeostasis, efflux of excitatory amino acids from nerve cells, increased energy metabolism and changes in cerebral blood flow (CBF). There is strong clinical and experimental evidence...... treatment strategies, which may be used to prevent or attenuate secondary neuronal damage in acutely injured human brain cortex caused by depolarization waves....

  3. NR2A contributes to genesis and propagation of cortical spreading depression in rats.

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    Bu, Fan; Du, Ruoxing; Li, Yi; Quinn, John P; Wang, Minyan

    2016-03-22

    Cortical spreading depression (CSD) is a transient propagating excitation of synaptic activity followed by depression, which is implicated in migraine. Increasing evidence points to an essential role of NR2A-containing NMDA receptors in CSD propagation in vitro; however, whether these receptors mediate CSD genesis in vivo requires clarification and the role of NR2A on CSD propagation is still under debate. Using in vivo CSD in rats with electrophysiology and in vitro CSD in chick retina with intrinsic optical imaging, we addressed the role of NR2A in CSD. We demonstrated that NVP-AAM077, a potent antagonist for NR2A-containing receptors, perfused through microdialysis probes, markedly reduced cortex susceptibility to CSD, but also reduced magnitude of CSD genesis in rats. Additionally, NVP-AAM077 at 0.3 nmol perfused into the contralateral ventricle, considerably suppressed the magnitude of CSD propagation wave and propagation rate in rats. This reduction in CSD propagation was also observed with TCN-201, a negative allosteric modulator selective for NR2A, at 3 μM, in the chick retina. Our data provides strong evidence that NR2A subunit contributes to CSD genesis and propagation, suggesting drugs selectively antagonizing NR2A-containing receptors might constitute a highly specific strategy treating CSD associated migraine with a likely better safety profile.

  4. Effects of Cortical Spreading Depression on Synaptic Activity, Blood Flow and Oxygen Consumption in Rat Cerebral Cortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard

    2010-01-01

    As the title of this thesis indicates I have during my PhD studied the effects of cortical spreading depression (CSD) on synaptic activity, blood flow and oxygen consumption in rat cerebral cortex. This was performed in vivo using an open cranial window approach in anesthetized rats. I applied...... two different sets of interneurons. Our data imply that for a given cortical area the amplitude of vascular signals will depend critically on the type of input and hence on the type of neurons activated. In the second study I investigated the effect of cortical spreading depression (CSD) on the evoked...... of neurovascular coupling after topical pretreatment with either inhibitor of CaN pathway (FK506), inhibitor of mPTP formation (NIM811) and combined inhibition of both pathways (FK506+NIM811 or cyclosporin A). A result indicating a potential new treatment aspect for disease states where CSD is known to be involved...

  5. Physical exercise versus fluoxetine: antagonistic effects on cortical spreading depression in Wistar rats.

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    Mirelle Costa Monteiro, Heloísa; Lima Barreto-Silva, Nathália; Elizabete Dos Santos, Gracyelle; de Santana Santos, Amanda; Séfora Bezerra Sousa, Mariana; Amâncio-Dos-Santos, Ângela

    2015-09-05

    The antidepressant fluoxetine and physical exercise exert similar effects on the serotoninergic system by increasing brain serotonin availability, and both show antagonistic action on cortical excitability. Here we provide the first assessment of the interaction of the two together on cortical spreading depression (CSD) in young adult rats. Wistar rats (40-60 days of life) received fluoxetine (10mg/kg/d, orogastrically) or an equivalent volume of water. Half of the animals from each condition were assigned to perform physical exercise in a treadmill, and the other half formed the sedentary (non-treadmill) control groups. Body parameters (Lee index and thoracic and abdominal circumferences) and the velocity of CSD propagation were investigated. Fluoxetine+exercise animals had less weight gain (78.68±3.19g) than either the fluoxetine-only (93.34±4.77g) or exercise-only group (97.04±3.48g), but body parameters did not differ among them. The velocity of CSD propagation was reduced in the fluoxetine-only and exercise-only groups compared to sedentary water controls (3.24±0.39mm/min). For the fluoxetine+exercise group, CSD velocity values were significantly lower (2.92±0.22mm/min) than for fluoxetine only (3.03±0.35mm/min); however, they were similar to values for the exercise-only group (2.96±0.23mm/min). These findings confirm the similar effects of fluoxetine and exercise and suggest a greater effect of physical exercise in reducing brain excitability.

  6. Increased susceptibility to cortical spreading depression in the mouse model of familial hemiplegic migraine type 2.

    Directory of Open Access Journals (Sweden)

    Loredana Leo

    2011-06-01

    Full Text Available Familial hemiplegic migraine type 2 (FHM2 is an autosomal dominant form of migraine with aura that is caused by mutations of the α2-subunit of the Na,K-ATPase, an isoform almost exclusively expressed in astrocytes in the adult brain. We generated the first FHM2 knock-in mouse model carrying the human W887R mutation in the Atp1a2 orthologous gene. Homozygous Atp1a2(R887/R887 mutants died just after birth, while heterozygous Atp1a2(+/R887 mice showed no apparent clinical phenotype. The mutant α2 Na,K-ATPase protein was barely detectable in the brain of homozygous mutants and strongly reduced in the brain of heterozygous mutants, likely as a consequence of endoplasmic reticulum retention and subsequent proteasomal degradation, as we demonstrate in transfected cells. In vivo analysis of cortical spreading depression (CSD, the phenomenon underlying migraine aura, revealed a decreased induction threshold and an increased velocity of propagation in the heterozygous FHM2 mouse. Since several lines of evidence involve a specific role of the glial α2 Na,K pump in active reuptake of glutamate from the synaptic cleft, we hypothesize that CSD facilitation in the FHM2 mouse model is sustained by inefficient glutamate clearance by astrocytes and consequent increased cortical excitatory neurotransmission. The demonstration that FHM2 and FHM1 mutations share the ability to facilitate induction and propagation of CSD in mouse models further support the role of CSD as a key migraine trigger.

  7. Mathematical Imaging and Modeling of Cortical Spreading Depression and Wound Healing

    Science.gov (United States)

    2015-02-05

    phase diagram that maps out when a retinal detachment is unstable, or is stable and will likely heal . We have begun to generalize this problem in two...Spreading Depression and W mmd Healing Sb. GRANT NUMBER Sc. PROGRAM ELEMENT NUMBER 611102 6. AUTHORS Sd. PROJECT NUMBER Tom Chou Se. TASK NUMBER...Spreading Depression and Wound Healing ." The research conducted under this grant represents advances made in image analysis, front tracking, modeling

  8. Minimum conditions for the induction of cortical spreading depression in brain slices

    Science.gov (United States)

    Tang, Yujie T.; Mendez, Jorge M.; Theriot, Jeremy J.; Sawant, Punam M.; López-Valdés, Héctor E.; Ju, Y. Sungtaek

    2014-01-01

    Cortical spreading depression (CSD) occurs during various forms of brain injury such as stroke, subarachnoid hemorrhage, and brain trauma, but it is also thought to be the mechanism of the migraine aura. It is therefore expected to occur over a range of conditions including the awake behaving state. Yet it is unclear how such a massive depolarization could occur under relatively benign conditions. Using a microfluidic device with focal stimulation capability in a mouse brain slice model, we varied extracellular potassium concentration as well as the area exposed to increased extracellular potassium to determine the minimum conditions necessary to elicit CSD. Importantly, we focused on potassium levels that are physiologically plausible (≤145 mM; the intracellular potassium concentration). We found a strong correlation between the threshold concentration and the slice area exposed to increased extracellular potassium: minimum area of exposure was needed with the highest potassium concentration, while larger areas were needed at lower concentrations. We also found that moderate elevations of extracellular potassium were able to elicit CSD in relatively small estimated tissue volumes that might be activated under noninjury conditions. Our results thus show that CSD may be inducible under the conditions that expected in migraine aura as well as those related to brain trauma. PMID:25122714

  9. In vivo imaging reveals that pregabalin inhibits cortical spreading depression and propagation to subcortical brain structures

    Science.gov (United States)

    Cain, Stuart M.; Bohnet, Barry; LeDue, Jeffrey; Yung, Andrew C.; Garcia, Esperanza; Tyson, John R.; Alles, Sascha R. A.; Han, Huili; van den Maagdenberg, Arn M. J. M.; Kozlowski, Piotr; MacVicar, Brian A.; Snutch, Terrance P.

    2017-01-01

    Migraine is characterized by severe headaches that can be preceded by an aura likely caused by cortical spreading depression (SD). The antiepileptic pregabalin (Lyrica) shows clinical promise for migraine therapy, although its efficacy and mechanism of action are unclear. As detected by diffusion-weighted MRI (DW-MRI) in wild-type (WT) mice, the acute systemic administration of pregabalin increased the threshold for SD initiation in vivo. In familial hemiplegic migraine type 1 mutant mice expressing human mutations (R192Q and S218L) in the CaV2.1 (P/Q-type) calcium channel subunit, pregabalin slowed the speed of SD propagation in vivo. Acute systemic administration of pregabalin in vivo also selectively prevented the migration of SD into subcortical striatal and hippocampal regions in the R192Q strain that exhibits a milder phenotype and gain of CaV2.1 channel function. At the cellular level, pregabalin inhibited glutamatergic synaptic transmission differentially in WT, R192Q, and S218L mice. The study describes a DW-MRI analysis method for tracking the progression of SD and provides support and a mechanism of action for pregabalin as a possible effective therapy in the treatment of migraine. PMID:28223480

  10. Computational model of cerebral blood flow redistribution during cortical spreading depression

    Science.gov (United States)

    Verisokin, Andrey Y.; Verveyko, Darya V.; Postnov, Dmitry E.

    2016-04-01

    In recent decades modelling studies on cortical spreading depression (CSD) and migraine waves successfully contributed to formation of modern view on these fundamental phenomena of brain physiology. However, due to the extreme complexity of object under study (brain cortex) and the diversity of involved physiological pathways, the development of new mathematical models of CSD is still a very relevant and challenging research problem. In our study we follow the functional modelling approach aimed to map the action of known physiological pathways to the specific nonlinear mechanisms that govern formation and evolution of CSD wave patterns. Specifically, we address the role of cerebral blood flow (CBF) redistribution that is caused by excessive neuronal activity by means of neurovascular coupling and mediates a spatial pattern of oxygen and glucose delivery. This in turn changes the local metabolic status of neural tissue. To build the model we simplify the web of known cell-to-cell interactions within a neurovascular unit by selecting the most relevant ones, such as local neuron-induced elevation of extracellular potassium concentration and biphasic response of arteriole radius. We propose the lumped description of distance-dependent hemodynamic coupling that fits the most recent experimental findings.

  11. [The Effect of Cortical Spreading Depression Wave on EEG Spectral Power Anaesthesed and Conscious Rats].

    Science.gov (United States)

    Koroleva, V I; Sakharov, D S; Bogdanov, A V

    2016-01-01

    EEG power changes in anaesthetized and conscious rats were studied (under repeated experiments) in wide frequency band (0.1-200 Hz) during cortical spreading depression wave (SD). In anaesthetized rats the decrease of EEG spectral power was shown through all diapasons under consideration. The most pronounced decay of the EEG power was marked in the 30-40 Hz band (27.3 ± 18.5, p = 2.46 x 10-(11)). In other frequency ranges the power decrease was less but its significance remained high. In conscious rats the simultaneous decay of the EEG power from 20 to 100 Hz range was also the most informative index of SD wave. The maximum power loss was found for band 30-40 Hz (11.2 ± 7.8, p = 2.55 x 10(-7)). It was shown that besides of EEG power decay the development of SD wave was characterized by the appearance of high frequency activity in front of SD and at the end of it. The increase of high-frequency activity in front of SD wave appeared in the ipsilateral hemisphere and moved along the cortex with the velocity of the SD wave itself. However the bursts of high frequency activity at the end of unilateral SD occurred simultaneously in both hemispheres and lasted 1.5-2.5 min. Findings contribute to detection of SD wave on basis of EEG spectral analysis.

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

    Science.gov (United States)

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

    2014-07-22

    Propagation of cortical spreading depression (CSD) to the subcortical structures could be the underlying mechanism of some neurological deficits in migraine with aura. The entorhinal cortex (EC) as a gray matter bridge between the neocortex and subcortical regions plays an important role in this propagation. In vitro combined neocortex-hippocampus brain slices were used to study the propagation pattern of CSD between the neocortex and the hippocampus. The effects of different compounds as well as tetanic electrical stimulations in the EC on propagation of CSD to the hippocampus were investigated. Repetitive induction of CSD by KCl injection in the somatosensory cortex enhanced the probability of CSD entrance to the hippocampus via EC. Local application of AMPA receptor blocker CNQX and cannabinoid receptor agonist WIN 55212-2 in EC facilitated the propagation of CSD to the hippocampus, whereas application of NMDA receptor blocker APV and GABAA 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.

  13. Randomized, double-blind, placebo-controlled, proof-of-concept study of the cortical spreading depression inhibiting agent tonabersat in migraine prophylaxis

    DEFF Research Database (Denmark)

    Goadsby, P J; Ferrari, M D; Csanyi, A

    2009-01-01

    Tonabersat is a novel putative migraine prophylactic agent with an unique stereospecific binding site in the brain. Tonabersat has been shown, in animal models, to inhibit experimentally induced cortical spreading depression, the likely underlying mechanism for migraine aura, and cerebrovascular ...

  14. Cytoarchitecture-Dependent Decrease in Propagation Velocity of Cortical Spreading Depression in the Rat Insular Cortex Revealed by Optical Imaging.

    Science.gov (United States)

    Fujita, Satoshi; Mizoguchi, Naoko; Aoki, Ryuhei; Cui, Yilong; Koshikawa, Noriaki; Kobayashi, Masayuki

    2016-04-01

    Cortical spreading depression (SD) is a self-propagating wave of depolarization accompanied by a substantial disturbance of the ionic distribution between the intra- and extracellular compartments. Glial cells, including astrocytes, play critical roles in maintenance of the extracellular environment, including ionic distribution. Therefore, SD propagation in the cerebral cortex may depend on the density of astrocytes. The present study aimed to examine the profile of SD propagation in the insular cortex (IC), which is located between the neocortex and paleocortex and is where the density of astrocytes gradually changes. The velocity of SD propagation in the neocortex, including the somatosensory, motor, and granular insular cortices (5.7 mm/min), was higher than that (2.8 mm/min) in the paleocortex (agranular insular and piriform cortices). Around thick vessels, including the middle cerebral artery, SD propagation was frequently delayed and sometimes disappeared. Immunohistological analysis of glial fibrillary acidic protein (GFAP) demonstrated the sparse distribution of astrocytes in the somatosensory cortex and the IC dorsal to the rhinal fissure, whereas the ventral IC showed a higher density of astrocytes. These results suggest that cortical cytoarchitectonic features, which possibly involve the distribution of astrocytes, are crucial for regulating the velocity of SD propagation in the cerebral cortex.

  15. Early malnutrition, but not age, modulates in the rat the L-Arginine facilitating effect on cortical spreading depression.

    Science.gov (United States)

    Frazão, Marília Ferreira; Silva de Seixas Maia, Luciana Maria; Guedes, Rubem Carlos Araújo

    2008-12-05

    Nutritional factors acting during brain development can permanently alter brain electrophysiology. L-Arginine is the precursor of nitric oxide synthesis, which can modulate brain function. Here we investigated the effect of early-in-life administration (during postnatal days 7-28) of L-Arginine (300 mg/(kg day)) on cortical spreading depression (CSD), recorded in well-nourished and malnourished (large litters technique) rats aged 30-40 days (young) and 90-110 days (adult). Compared to water-treated controls, well-nourished L-Arginine-treated rats, but not the malnourished ones, displayed higher CSD velocities (Pbrain weights. It is concluded that early L-Arginine treatment long lastingly increased brain CSD-susceptibility and this effect is abolished by early malnutrition.

  16. Nitroglycerin enhances the propagation of cortical spreading depression: comparative studies with sumatriptan and novel kynurenic acid analogues

    Directory of Open Access Journals (Sweden)

    Knapp L

    2016-12-01

    Full Text Available Levente Knapp,1 Bence Szita,1 Kitti Kocsis,1,2 László Vécsei,2,3 József Toldi1,2 1Department of Physiology, Anatomy, and Neuroscience, University of Szeged, 2MTA-SZTE Neuroscience Research Group, 3Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Centre, University of Szeged, Szeged, Hungary Background: The complex pathophysiology of migraine is not yet clearly understood; therefore, experimental models are essential for the investigation of the processes related to migraine headache, which include cortical spreading depression (CSD and NO donor-induced neurovascular changes. Data on the assessment of drug efficacy in these models are often limited, which prompted us to investigate a novel combined migraine model in which an effective pharmacon could be more easily identified. Materials and methods: In vivo electrophysiological experiments were performed to investigate the effect of nitroglycerin (NTG on CSD induced by KCl application. In addition, sumatriptan and newly synthesized neuroactive substances (analogues of the neuromodulator kynurenic acid [KYNA] were also tested. Results: The basic parameters of CSDs were unchanged following NTG administration; however, propagation failure was decreased compared to the controls. Sumatriptan decreased the number of CSDs, whereas propagation failure was as minimal as in the NTG group. On the other hand, both of the KYNA analogues restored the ratio of propagation to the control level. Discussion: The ratio of propagation appeared to be the indicator of the effect of NTG. This is the first study providing direct evidence that NTG influences CSD; furthermore, we observed different effects of sumatriptan and KYNA analogues. Sumatriptan changed the generation of CSDs, whereas the analogues acted on the propagation of the waves. Our experimental design overlaps with a large spectrum of processes present in migraine pathophysiology, and it can be a useful experimental model

  17. The effect of a gap-junction blocker, carbenoxolone, on ischemic brain injury and cortical spreading depression.

    Science.gov (United States)

    Tamura, K; Alessandri, B; Heimann, A; Kempski, O

    2011-10-27

    Cortical spreading depression (CSD) has been shown to cause secondary cell loss in experimental models of brain injury and in patients, and blocking of CSD is a potential neuroprotective strategy. Here we tested the hypothesis that gap junctions affect CSD under physiological conditions as well as infarct development in a rat two-vein occlusion model suited to study pathophysiology of the penumbra (n = 71). We applied the gap junction blocker carbenoxolone (CBX) or saline intra-ventricularly. Interestingly, CBX temporarily increased systemic blood pressure and cortical blood flow (41% and 53%, 15 min after 250 μg CBX). We induced CSD with cortical microinjection of potassium chloride (KCl), counted how many spontaneous CSDs after CSD induction were elicited and measured the propagation velocity. After 250 μg CBX administration, significant 37.5 ± 6.5 additional CSDs were seen. CSD velocity increased significantly after 50 μg and 250 μg CBX. Occlusion of two adjacent cortical veins using Rose Bengal dye and fiberoptic illumination followed by 250 μg CBX or saline showed a significant more than doubling of infarct volumes 7 days after CBX. The current experiments provide evidence that CBX can accelerate the initiation and propagation of CSD suggesting opening of gap junctions is not required for CSD propagation. Blocking gap junctions worsens outcome from focal cerebral ischemia. Hence, measures intended to improve spatial buffering via astroglial gap junctions could have therapeutic potential in disease processes involving CSD. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Influence of ovarian hormones on cortical spreading depression and its suppression by L-kynurenine in rat.

    Directory of Open Access Journals (Sweden)

    Virginie Chauvel

    Full Text Available Migraine is sexually dimorphic and associated in 20-30% of patients with an aura most likely caused by cortical spreading depression (CSD. We have previously shown that systemic L-kynurenine (L-KYN, the precursor of kynurenic acid, suppresses CSD and that this effect depends on the stage of the estrous cycle in female rats. The objectives here are to determine the influence of ovarian hormones on KCl-induced CSD and its suppression after L-KYN by directly modulating estradiol or progesterone levels in ovariectomized rats. Adult female rats were ovariectomized and subcutaneously implanted with silastic capsules filled with progesterone or 17β-estradiol mixed with cholesterol, with cholesterol only or left empty. Two weeks after the ovariectomy/capsule implantation, the animals received an i.p. injection of L-KYN (300 mg/kg or NaCl as control. Thirty minutes later CSDs were elicited by applying KCl over the occipital cortex and recorded by DC electrocorticogram for 1 hour. The results show that both estradiol and progesterone increase CSD frequency after ovariectomy. The suppressive effect of L-KYN on CSD frequency, previously reported in normal cycling females, is not found anymore after ovariectomy, but reappears after progesterone replacement therapy. Taken together, these results emphasize the complex role of sex hormones on cortical excitability. The CSD increase by estradiol and, more surprisingly, progesterone may explain why clinically migraine with aura appears or worsens during pregnancy or with combined hormonal treatments.

  19. Unexpected effects of peripherally administered kynurenic acid on cortical spreading depression and related blood–brain barrier permeability

    Directory of Open Access Journals (Sweden)

    Oláh G

    2013-09-01

    Full Text Available Gáspár Oláh,1 Judit Herédi,1 Ákos Menyhárt,1 Zsolt Czinege,2 Dávid Nagy,1 János Fuzik,1 Kitti Kocsis,1 Levente Knapp,1 Erika Krucsó,1 Levente Gellért,1 Zsolt Kis,1 Tamás Farkas,1 Ferenc Fülöp,3 Árpád Párdutz,4 János Tajti,4 László Vécsei,4 József Toldi1 1Department of Physiology, Anatomy and Neuroscience, 2Department of Software Engineering, 3Institute of Pharmaceutical Chemistry and MTA-SZTE Research Group for Stereochemistry, 4Department of Neurology and MTA-SZTE Neuroscience Research Group, University of Szeged, Szeged, Hungary Abstract: Cortical spreading depression (CSD involves a slowly-propagating depolarization wave in the cortex, which can appear in numerous pathophysiological conditions, such as migraine with aura, stroke, and traumatic brain injury. Neurons and glial cells are also depolarized transiently during the phenomena. CSD is followed by a massive increase in glutamate release and by changes in the brain microcirculation. The aim of this study was to investigate the effects of two N-methyl-D-aspartate receptor antagonists, endogenous kynurenic acid (KYNA and dizocilpine, on CSD and the related blood–brain barrier (BBB permeability in rats. In intact animals, KYNA hardly crosses the BBB but has some positive features as compared with its precursor L-Kynurenine, which is frequently used in animal studies (KYNA cannot be metabolized to excitotoxic agents such as 3-hydroxy-L-kynurenine and quinolinic acid. We therefore investigated the possible effects of peripherally administered KYNA. Repetitive CSD waves were elicited by the application of 1 M KCl solution to the cortex. Direct current-electrocorticograms were measured for 1 hour. Four parameters of the waves were compared. Evans blue dye and fluorescent microscopy were used to study the possible changes in the permeability of the BBB. The results demonstrated that N-methyl-D-aspartate receptor antagonists can reduce the number of CSD waves and decrease

  20. Cortical spreading depression and involvement of the motor cortex, auditory cortex, and cerebellum in eyeblink classical conditioning of the rabbit.

    Science.gov (United States)

    Case, Gilbert R; Lavond, David G; Thompson, Richard F

    2002-09-01

    The interrelationships of cerebellar and cerebral neural circuits in the eyeblink paradigm were explored with the controlled application of cortical spreading depression (CSD) and lidocaine in the New Zealand albino rabbit. The initial research focus was directed toward the involvement of the motor cortex in the conditioned eyeblink response. However, CSD timing and triangulation results indicate that other areas in the cerebral cortex, particularly the auditory cortex (acoustic conditioned stimulus), appear to be critical for the CSD effect on the eyeblink response. In summary: (1) CSD can be elicited, monitored, and timed and its side effects controlled in 97% of awake rabbits in the right and/or left cerebral hemisphere(s) during eyeblink conditioning. (2) The motor cortex appears to play little or no part in classical conditioning of the eyeblink in the rabbit in the delay paradigm. (3) Inactivating the auditory cortex with CSD or lidocaine temporarily impairs the conditioned response during the first 5 to 15 days of training, but has little effect past that point.

  1. Large-Scale Mass Spectrometry Imaging Investigation of Consequences of Cortical Spreading Depression in a Transgenic Mouse Model of Migraine

    Science.gov (United States)

    Carreira, Ricardo J.; Shyti, Reinald; Balluff, Benjamin; Abdelmoula, Walid M.; van Heiningen, Sandra H.; van Zeijl, Rene J.; Dijkstra, Jouke; Ferrari, Michel D.; Tolner, Else A.; McDonnell, Liam A.; van den Maagdenberg, Arn M. J. M.

    2015-06-01

    Cortical spreading depression (CSD) is the electrophysiological correlate of migraine aura. Transgenic mice carrying the R192Q missense mutation in the Cacna1a gene, which in patients causes familial hemiplegic migraine type 1 (FHM1), exhibit increased propensity to CSD. Herein, mass spectrometry imaging (MSI) was applied for the first time to an animal cohort of transgenic and wild type mice to study the biomolecular changes following CSD in the brain. Ninety-six coronal brain sections from 32 mice were analyzed by MALDI-MSI. All MSI datasets were registered to the Allen Brain Atlas reference atlas of the mouse brain so that the molecular signatures of distinct brain regions could be compared. A number of metabolites and peptides showed substantial changes in the brain associated with CSD. Among those, different mass spectral features showed significant ( t-test, P migraine pathophysiology. The results also demonstrate the utility of aligning MSI datasets to a common reference atlas for large-scale MSI investigations.

  2. Nitroglycerin enhances the propagation of cortical spreading depression: comparative studies with sumatriptan and novel kynurenic acid analogues

    Science.gov (United States)

    Knapp, Levente; Szita, Bence; Kocsis, Kitti; Vécsei, László; Toldi, József

    2017-01-01

    Background The complex pathophysiology of migraine is not yet clearly understood; therefore, experimental models are essential for the investigation of the processes related to migraine headache, which include cortical spreading depression (CSD) and NO donor-induced neurovascular changes. Data on the assessment of drug efficacy in these models are often limited, which prompted us to investigate a novel combined migraine model in which an effective pharmacon could be more easily identified. Materials and methods In vivo electrophysiological experiments were performed to investigate the effect of nitroglycerin (NTG) on CSD induced by KCl application. In addition, sumatriptan and newly synthesized neuroactive substances (analogues of the neuromodulator kynurenic acid [KYNA]) were also tested. Results The basic parameters of CSDs were unchanged following NTG administration; however, propagation failure was decreased compared to the controls. Sumatriptan decreased the number of CSDs, whereas propagation failure was as minimal as in the NTG group. On the other hand, both of the KYNA analogues restored the ratio of propagation to the control level. Discussion The ratio of propagation appeared to be the indicator of the effect of NTG. This is the first study providing direct evidence that NTG influences CSD; furthermore, we observed different effects of sumatriptan and KYNA analogues. Sumatriptan changed the generation of CSDs, whereas the analogues acted on the propagation of the waves. Our experimental design overlaps with a large spectrum of processes present in migraine pathophysiology, and it can be a useful experimental model for drug screening. PMID:28053504

  3. Increased 20-HETE synthesis explains reduced cerebral blood flow but not impaired neurovascular coupling after cortical spreading depression in rat cerebral cortex

    DEFF Research Database (Denmark)

    Fordsmann, Jonas Christoffer; ko, Rebecca; Choi, Hyun B

    2013-01-01

    Cortical spreading depression (CSD) is associated with release of arachidonic acid (AA), impaired neurovascular coupling, and reduced cerebral blood flow (CBF), caused by cortical vasoconstriction. We tested the hypothesis that the released AA is metabolized by the cytochrome P450 enzyme to produce...... neurovascular coupling after CSD. These findings suggest that CSD-induced increments in 20-HETE cause the reduction in CBF after CSD, and that the attenuation of stimulation-induced CBF responses after CSD has a different mechanism. We suggest that blockade of 20-HETE synthesis may be clinically relevant...

  4. Spreading depression induces expression of calcium-independent protein kinase C subspecies in ischaemia-sensitive cortical layers: regulation by N-methyl-D-aspartate receptors and glucocorticoids.

    Science.gov (United States)

    Koponen, S; Keinänen, R; Roivainen, R; Hirvonen, T; Närhi, M; Chan, P H; Koistinaho, J

    1999-01-01

    Spreading depression is a wave of sustained depolarization challenging the energy metabolism of the cells without causing irreversible damage. In the ischaemic brain, sreading depression-like depolarization contributes to the evolution of ischaemia to infarction. The depolarization is propagated by activation of N-methyl-D-aspartate receptors, but changes in signal transduction downstream of the receptors are not known. Because protein phosphorylation is a general mechanism whereby most cellular processes are regulated, and inhibition of N-methyl-D-aspartate receptors or protein kinase C is neuroprotective, the expression of protein kinase C subspecies in spreading depression was examined. Cortical treatment with KCl induced an upregulation of protein kinase Cdelta and zeta messenger RNA at 4 and 8 h, whereas protein kinase Calpha, beta, gamma and epsilon did not show significant changes. The gene induction was the strongest in layers 2 and 3, and was followed by an increased number of protein kinase Cdelta-immunoreactive neurons. Protein kinase Cdelta and zeta inductions were inhibited by pretreatment with an N-methyl-D-aspartate receptor antagonist, dizocilpine maleate, which also blocked spreading depression propagation, and with dexamethasone, which acted without blocking the propagation. Quinacrine, a phospholipase A2 inhibitor, reduced only protein kinase C5 induction. In addition, N(G)(-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, did not influence protein kinase Cdelta or zeta induction, whereas 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione, an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate receptor antagonist, and the cyclo-oxygenase inhibitors indomethacin and diclophenac tended to increase gene expression. The data show that cortical spreading depression induces Ca2(+)-independent protein kinase C subspecies delta and zeta, but not Ca(2+)-dependent subspecies, through activation of N-methyl-D-aspartate receptors and

  5. Enhanced excitatory transmission at cortical synapses as the basis for facilitated spreading depression in Ca(v)2.1 knockin migraine mice.

    Science.gov (United States)

    Tottene, Angelita; Conti, Rossella; Fabbro, Alessandra; Vecchia, Dania; Shapovalova, Maryna; Santello, Mirko; van den Maagdenberg, Arn M J M; Ferrari, Michel D; Pietrobon, Daniela

    2009-03-12

    Migraine is a common disabling brain disorder. A subtype of migraine with aura (familial hemiplegic migraine type 1: FHM1) is caused by mutations in Ca(V)2.1 (P/Q-type) Ca(2+) channels. Knockin mice carrying a FHM1 mutation show increased neuronal P/Q-type current and facilitation of induction and propagation of cortical spreading depression (CSD), the phenomenon that underlies migraine aura and may activate migraine headache mechanisms. We studied cortical neurotransmission in neuronal microcultures and brain slices of FHM1 mice. We show gain of function of excitatory neurotransmission due to increased action-potential-evoked Ca(2+) influx and increased probability of glutamate release at pyramidal cell synapses but unaltered inhibitory neurotransmission at fast-spiking interneuron synapses. Using an in vitro model of CSD, we show a causative link between enhanced glutamate release and CSD facilitation. The synapse-specific effect of FHM1 mutations points to disruption of excitation-inhibition balance and neuronal hyperactivity as the basis for episodic vulnerability to CSD ignition in migraine.

  6. Prooxidant versus antioxidant brain action of ascorbic acid in well-nourished and malnourished rats as a function of dose: a cortical spreading depression and malondialdehyde analysis.

    Science.gov (United States)

    Mendes-da-Silva, Rosângela Figueiredo; Lopes-de-Morais, Andréia Albuquerque Cunha; Bandim-da-Silva, Maria Eduarda; Cavalcanti, Gabriela de Araujo; Rodrigues, Ana Rafaela Oliveira; Andrade-da-Costa, Belmira Lara da Silveira; Guedes, Rubem Carlos Araújo

    2014-11-01

    Although ascorbic acid (AA) is an antioxidant, under certain conditions it can facilitate oxidation, which may underlie the opposite actions of AA on brain excitability in distinct seizure models. Here, we investigated whether chronic AA administration during brain development alters cortical excitability as a function of AA dose, as indexed by cortical spreading depression (CSD) and by the levels of lipid peroxidation-induced malondialdehyde. Well-nourished and early-malnourished rats received per gavage 30, 60, or 120 mg/kg/d of AA, saline, or no gavage treatment (naïve group) at postnatal days 7-28. CSD propagation and malondialdehyde levels were analyzed at 30-40 days. Confirming previous observations, CSD velocities were significantly higher in the early-malnourished groups than in the well-nourished groups. AA dose was important: 30 mg/kg/d AA decelerated CSD and reduced malondialdehyde levels, whereas 60 mg/kg/d and 120 mg/kg/d accelerated CSD and augmented malondialdehyde levels compared with the corresponding saline and naïve groups. Our findings reinforce previous suggestion that AA acts as an antioxidant in the brain when administered at low doses, but as a prooxidant at high doses, as indicated by CSD propagation and malondialdehyde levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Estrogen-dependent effects of 5-hydroxytryptophan on cortical spreading depression in rat: Modelling the serotonin-ovarian hormone interaction in migraine aura.

    Science.gov (United States)

    Chauvel, Virginie; Multon, Sylvie; Schoenen, Jean

    2017-01-01

    Background Cortical spreading depression (CSD) is the likely culprit of the migraine aura. Migraine is sexually dimorphic and thought to be a "low 5-HT" condition. We sought to decipher the interrelation between serotonin, ovarian hormones and cortical excitability in a model of migraine aura. Methods Occipital KCl-induced CSDs were recorded for one hour at parieto-occipital and frontal levels in adult male (n = 16) and female rats (n = 64) one hour after intraperitoneal (i.p.) injection of 5-hydroxytryptophan (5-HTP) or NaCl. Sixty-five oophorectomized females were treated with estradiol- (E2) or cholesterol- (Chol) filled capsules. Two weeks later we recorded CSDs after 5-HTP/NaCl injections before or 20 hours after capsule removal. Results 5-HTP had no effect in males, but decreased CSD frequency in cycling females, significantly so during estrus, at parieto-occipital (-3.5CSD/h, p HTP was significant only in E2-treated rats (-3.4CSD/h, p = 0.006 and -1.8CSD/h, p = 0.029). Neither the estrous cycle phase, nor E2 or 5-HTP treatments significantly modified CSD propagation velocity. Conclusion 5-HTP decreases CSD occurrence in the presence of ovarian hormones, suggesting its potential efficacy in migraine with aura prophylaxis in females. Elevated E2 levels increase CSD susceptibility, while estrogen withdrawal decreases CSD. In a translational perspective, these findings may explain why migraine auras can appear during pregnancy and why menstrual-related migraine attacks are rarely associated with an aura.

  8. The continuum of spreading depolarizations in acute cortical lesion development

    DEFF Research Database (Denmark)

    Hartings, Jed A; Shuttleworth, C William; Kirov, Sergei A;

    2017-01-01

    A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum...... of spreading mass depolarizations, a concept that is central to understanding their pathologic effects. Within minutes of acute severe ischemia, the onset of persistent depolarization triggers the breakdown of ion homeostasis and development of cytotoxic edema. These persistent changes are diagnosed....... The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion...

  9. Neonatal taurine and alanine modulate anxiety-like behavior and decelerate cortical spreading depression in rats previously suckled under different litter sizes.

    Science.gov (United States)

    Francisco, Elian da Silva; Guedes, Rubem Carlos Araújo

    2015-11-01

    The amino acids taurine and alanine play a role in several physiological processes, including behavior and the electrical activity of the brain. In this study, we investigated the effect of treatment with taurine or alanine on anxiety-like behavior and the excitability-dependent phenomenon known as cortical spreading depression (CSD), using rats suckled in litters with 9 and 15 pups (groups L9 and L15). From postnatal days 7 to 27, the animals received per gavage 300 mg/kg/day of taurine or alanine or both. At 28 days, we tested the animals in the elevated plus maze, and at 33-35 days, we recorded CSD and analyzed its velocity of propagation, amplitude, and duration. Compared with water-treated controls, the L9 groups treated with taurine or alanine displayed anxiolytic behavior (higher number of entries in the open arms; p taurine, alanine, or both) treated at adulthood (90-110 days). The L15 condition resulted in smaller durations and higher CSD velocities compared with the L9 condition. Besides reinforcing previous evidence of behavioral modulation by taurine and alanine, our data are the first confirmation that treatment with these amino acids decelerates CSD regardless of lactation conditions (normal versus unfavorable lactation) or age at amino acid administration (young versus adult). The results suggest a modulating role for both amino acids on anxiety behavior and neuronal electrical activity.

  10. Endogenous mechanisms underlying the activation and sensitization of meningeal nociceptors: the role of immuno-vascular interactions and cortical spreading depression.

    Science.gov (United States)

    Levy, Dan

    2012-06-01

    Migraine is considered one of the most prevalent neurological disorders but its underlying pathophysiology is poorly understood. Over the past two decades, it became widely accepted that activation of primary afferent nociceptive neurons that innervate the intracranial meninges serves as a key process that mediates the throbbing head pain of migraine. Knowledge about the endogenous factors that play a role in promoting this neural process during a migraine attack slowly begins to increase, and a better understanding remains one of the holy grails in migraine research. One endogenous process, which has been invoked as a major player in the genesis of migraine pain, is cortical spreading depression (CSD). Until recently, however, this notion was only supported by indirect evidence. Recently, electrophysiological data provided the first direct evidence that CSD is indeed a powerful endogenous process that can lead to persistent activation of meningeal nociceptors and the migraine pain pathway. CSD has been suggested to promote persistent sensitization and ensuing activation of meningeal nociceptors through a mechanism involving local neurogenic inflammation including the activation of mast cells and macrophages and subsequent release of inflammatory mediators. Local action of such nociceptive mediators can increase the responsiveness of meningeal nociceptors. Recent studies provided key experimental data implicating complex meningeal immuno-vascular interactions, in particular, the interplay between proinflammatory cytokines, the meningeal vasculature and immune cells, in enhancing the responses of meningeal nociceptors.

  11. l-Citrulline ameliorates cerebral blood flow during cortical spreading depression in rats: Involvement of nitric oxide- and prostanoids-mediated pathway.

    Science.gov (United States)

    Kurauchi, Yuki; Mokudai, Koichi; Mori, Asami; Sakamoto, Kenji; Nakahara, Tsutomu; Morita, Masahiko; Kamimura, Ayako; Ishii, Kunio

    2017-02-17

    l-Citrulline is a potent precursor of l-arginine, and exerts beneficial effect on cardiovascular system via nitric oxide (NO) production. Migraine is one of the most popular neurovascular disorder, and imbalance of cerebral blood flow (CBF) observed in cortical spreading depression (CSD) contributes to the mechanism of migraine aura. Here, we investigated the effect of l-citrulline on cardiovascular changes to KCl-induced CSD. in rats. Intravenous injection of l-citrulline prevented the decrease in CBF, monitored by laser Doppler flowmetry, without affecting mean arterial pressure and heart rate during CSD. Moreover, l-citrulline attenuated propagation velocity of CSD induced by KCl. The effect of l-citrulline on CBF change was prevented by l-NAME, an inhibitor of NO synthase, but not by indomethacin, an inhibitor of cyclooxygenase. On the other hand, attenuation effect of l-citrulline on CSD propagation velocity was prevented not only by l-NAME but also by indomethacin. In addition, propagation velocity of CSD was attenuated by intravenous injection of NOR3, a NO donor, which was diminished by ODQ, an inhibitor of soluble guanylyl cyclase. These results suggest that NO/cyclic GMP- and prostanoids-mediated pathway differently contribute to the effect of l-citrulline on the maintenance of CBF.

  12. Spreading depression transiently disrupts myelin via interferon-gamma signaling.

    Science.gov (United States)

    Pusic, Aya D; Mitchell, Heidi M; Kunkler, Phillip E; Klauer, Neal; Kraig, Richard P

    2015-02-01

    Multiple sclerosis and migraine with aura are clinically correlated and both show imaging changes suggestive of myelin disruption. Furthermore, cortical myelin loss in the cuprizone animal model of multiple sclerosis enhances susceptibility to spreading depression, the likely underlying cause of migraine with aura. Since multiple sclerosis pathology involves inflammatory T cell lymphocyte production of interferon-gamma and a resulting increase in oxidative stress, we tested the hypothesis that spreading depression disrupts myelin through similar signaling pathways. Rat hippocampal slice cultures were initially used to explore myelin loss in spreading depression, since they contain T cells, and allow for controlled tissue microenvironment. These experiments were then translated to the in vivo condition in neocortex. Spreading depression in slice cultures induced significant loss of myelin integrity and myelin basic protein one day later, with gradual recovery by seven days. Myelin basic protein loss was abrogated by T cell depletion, neutralization of interferon-gamma, and pharmacological inhibition of neutral sphingomyelinase-2. Conversely, one day after exposure to interferon-gamma, significant reductions in spreading depression threshold, increases in oxidative stress, and reduced levels of glutathione, an endogenous neutral sphingomyelinase-2 inhibitor, emerged. Similarly, spreading depression triggered significant T cell accumulation, sphingomyelinase activation, increased oxidative stress, and reduction of gray and white matter myelin in vivo. Myelin disruption is involved in spreading depression, thereby providing pathophysiological links between multiple sclerosis and migraine with aura. Myelin disruption may promote spreading depression by enhancing aberrant excitability. Thus, preservation of myelin integrity may provide novel therapeutic targets for migraine with aura.

  13. Familial Hemiplegic Migraine and Spreading Depression

    Directory of Open Access Journals (Sweden)

    Hadi KAZEMI

    2014-07-01

    mutations. Neurology 2009 31;72(13:1178-83.Thomsen LL, Ostergaard E, Olesen J, Russell MB. Evidence for a separate type of migraine with aura: sporadic hemiplegic migraine. Neurology 2003;60(4:595-601.van den Maagdenberg AM, Haan J, Terwindt GM, Ferrari MD. Migraine: gene mutations and functional consequences. Curr Opin Neurol 2007; 20:299–305.Gritz SM, Radcliffe RA. Genetic effects of ATP1A2 in familial hemiplegic migraine type II and animal models. Hum Genomics 2013;5;7:8.Ophoff RA, Terwindt GM, Vergouwe MN, et al. Familial hemiplegic migraine and episodic ataxia type-2 are caused by mutations in the Ca2+ channel gene CACNL1A4. Cell 1996;87:543–552.Gargus JJ, Tournay A. Novel Mutation Confirms Seizure Locus SCN1A is Also Familial Hemiplegic Migraine Locus FHM3.PediatrNeurol 2007;37:407-410.Tottene A, Conti R, Fabbro A, Vecchia D, Shapovalova M, Santello M, et al.Enhanced excitatory transmission at cortical synapses as the basis for facilitated spreading depression in Ca(v2.1 knockin migraine mice. Neuron 2009;61(5:762-73.Terwindt GM, Ophoff RA, Haan J, Sandkuijl LA, Frants RR, Ferrari MD. Migraine, ataxia and epilepsy: a challenging spectrum of genetically determined calcium channelopathies. Dutch Migraine Genetics Research Group. Eur J Hum Genet 1998;6(4:297-307.Terwindt GM, Ophoff RA, van Eijk R, Vergouwe MN, Haan J, Frants RR, et al. Dutch Migraine Genetics Research Group. Involvement of the CACNA1A gene containing region on 19p13 in migraine with and without aura. Neurology 2001;56(8:1028-32.Franceschini A, Vilotti S, Ferrari MD, van den Maagdenberg AM, Nistri A, Fabbretti E. TNFα levels and macrophages expression reflect an inflammatory potential of trigeminal ganglia in a mouse model of familial hemiplegic migraine. PLoS One 2013;8:e52394.Kodangattil JN, Möddel G, Müller, M, Weber W, Gorji A.The inflammatory chemokine CXCL10 modulates synaptic plasticity and neuronal activity in the hippocampus. European Journal of Inflammation 2012;10(3:311-328Leao AAP

  14. [Cortical spreading depolarization: a new pathophysiological mechanism in neurological diseases].

    Science.gov (United States)

    Sánchez-Porras, Renán; Robles-Cabrera, Adriana; Santos, Edgar

    2014-05-20

    Cortical spreading depolarization is a wave of almost complete depolarization of the neuronal and glial cells that occurs in different neurological diseases such as migraine with aura, subarachnoid hemorrhage, intracerebral hemorrhage, head trauma and stroke. These depolarization waves are characterized by a change in the negative potential with an amplitude between -10 and -30mV, duration of ∼1min and changes in the ion homeostasis between the intra- and extracellular space. This results in neuronal edema and dendritic distortion. Under pathologic states of hypoperfusion, cortical spreading depolarization can produce oxidative stress, worsen hypoxia and induce neuronal death. This is due to intense arterial vasoconstriction produced by an inverse response called spreading ischemia. Only in the last years there has been an electrophysiological confirmation of cortical spreading depolarization in human brains. Occurrence of cortical spreading depolarization has been associated with worse outcome in patients. Currently, increased knowledge regarding the pathophysiologic mechanisms supports the hypothetical correlation of cortical spreading depolarization with brain damage in humans. There are diverse therapeutic alternatives that promise inhibition of cortical spreading depolarization and subsequent better outcomes. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  15. Enhanced subcortical spreading depression in familial hemiplegic migraine type 1 mutant mice.

    Science.gov (United States)

    Eikermann-Haerter, Katharina; Yuzawa, Izumi; Qin, Tao; Wang, Yumei; Baek, Kwangyeol; Kim, Young Ro; Hoffmann, Ulrike; Dilekoz, Ergin; Waeber, Christian; Ferrari, Michel D; van den Maagdenberg, Arn M J M; Moskowitz, Michael A; Ayata, Cenk

    2011-04-13

    Familial hemiplegic migraine type 1, a monogenic migraine variant with aura, is linked to gain-of-function mutations in the CACNA1A gene encoding Ca(V)2.1 channels. The S218L mutation causes severe channel dysfunction, and paroxysmal migraine attacks can be accompanied by seizures, coma, and hemiplegia; patients expressing the R192Q mutation exhibit hemiplegia only. Familial hemiplegic migraine knock-in mice expressing the S218L or R192Q mutation are highly susceptible to cortical spreading depression, the electrophysiological surrogate for migraine aura, and develop severe and prolonged motor deficits after spreading depression. The S218L mutants also develop coma and seizures and sometimes die. To investigate underlying mechanisms for these symptoms, we used multielectrode electrophysiological recordings, diffusion-weighted magnetic resonance imaging, and c-fos immunohistochemistry to trace spreading depression propagation into subcortical structures. We showed that unlike the wild type, cortical spreading depression readily propagated into subcortical structures in both familial hemiplegic migraine type 1 mutants. Whereas the facilitated subcortical spread appeared limited to the striatum in R192Q, hippocampal and thalamic spread was detected in the S218L mutants with an allele-dosage effect. Both strains exhibited increased susceptibility to subcortical spreading depression and reverberating spreading depression waves. Altogether, these data show that spreading depression propagates between cortex, basal ganglia, diencephalon, and hippocampus in genetically susceptible brains, which could explain the prolonged hemiplegia, coma, and seizure phenotype in this variant of migraine with aura.

  16. Persistent increase in oxygen consumption and impaired neurovascular coupling after spreading depression in rat neocortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard; Lauritzen, Martin

    2009-01-01

    trauma. Here we tested the hypothesis that single episodes of CSD induced acute hypoxia, and prolonged impairment of neurovascular and neurometabolic coupling. Cortical spreading depression was induced in rat frontal cortex, whereas cortical electrical activity and local field potentials (LFPs) were...... neurovascular coupling was explained by both reduced vascular reactivity and suppressed function of cortical inhibitory interneurons. The protracted effects of CSD on basal CMRO(2) and neurovascular coupling may contribute to cellular dysfunction in patients with migraine and acutely injured cerebral cortex....

  17. 格列本脲对大鼠皮层扩散性抑制中脑血管的调节作用%Regulation of Pial Artery by Glibenclamide During Cortical Spreading Depression in Rats

    Institute of Scientific and Technical Information of China (English)

    杨媛媛; 李鹏程; 曾绍群; 骆清铭

    2006-01-01

    皮层扩散性抑制(cortical spreading depression,CSD)是研究偏头痛、脑梗塞等疾病的重要病理模型.已有研究表明,在普遍被观察到的CSD过程中软脑膜动脉血管大幅度舒张之前,还存在一个较小幅度的软脑膜动脉扩张和收缩.但其中的脑血管调节机制尚不清楚.采用550 nm的内源信号光学成像(opticalintrinsic signalimaging,OISI)监测ATP敏感钾离子通道(ATP-sensitive potassium channels,KATP)的阻断剂格列本脲(glibenclamide,glyb),对针刺诱导的大鼠CSD过程中软脑膜动脉血管舒缩过程的影响.实验中观测到软脑膜血管的初始小收缩(initial slightconstriction,ISC)相对于对照组显著减弱,其中应用10μmol/L glyb时,74.5%的ISC被完全抑制,100μmol/L glyb时则有96.2%的ISC完全消失.相对于CSD发生前,软脑膜动脉血管大幅舒张(large dilation,LD)的峰值也分别显著增强了(53.8±19.3)%和(59.8±19.6)%.结果表明,可能是神经元上的KATP在CSD过程中被glyb阻断从而抑制了软脑膜动脉血管的收缩.

  18. 大鼠皮层扩散性抑制过程的在体内源光信号成像%In vivo Optical Imaging of Intrinsic Signal During Cortical Spreading Depression in Rats

    Institute of Scientific and Technical Information of China (English)

    李鹏程; 陈尚宾; 骆卫华; 骆清铭

    2003-01-01

    皮层扩散性抑制(cortical spreading depression,CSD)是研究偏头痛、脑梗塞等疾病的一种重要病理模型.而CSD过程中伴随发生的皮层血液动力学变化目前尚不完全清楚.利用高分辨的内源光信号成像技术,在体观测了大鼠CSD产生和发展过程中540 nm及660 nm波长皮层反射内源光信号变化的时空动力学特征,分析讨论了引起这一内源光信号变化可能的内在生理机制.实验结果显示,CSD诱发的内源光信号变化呈现多时相的特点,其传播由刺激中心以同心圆的样式向周围扩散,速度约为(3.7±0.4) mm/min.对于540 nm,CSD引起了皮层反射光强的降低[幅度(-2.1±1.2)%, 持续时程(16.2±3.8)s],升高 [幅度(2.9±1.6)%, 持续时程(13.8±2.2)s],再降低 [幅度(-14.2±4.5)%, 持续时程(40.6±8.4)s]和再升高持续时程[(146.2±40.3)s],同时观测到软脑膜动脉的大幅度舒张,血管管径变化峰值增大了(69.2±26.1)%.而对于660 nm, 内源光信号变化的时间特性在皮质区主要表现为反射光强的增大[幅度(3.8±0.6)%, 持续时程(17.9±5.1)s],减小[幅度(-3.0±1.7)%, 持续时程(43.3±6.4)s]和稍后持续缓慢的光强增加.

  19. Spreading depression and the clinical correlates of migraine.

    Science.gov (United States)

    Eikermann-Haerter, Katharina; Negro, Andrea; Ayata, Cenk

    2013-01-01

    Migraine is the most common neurologic condition. One-third of migraineurs experience transient neurologic symptoms, the so-called aura. There is strong evidence that spreading depression (SD) is the electrophysiologic substrate of migraine aura. SD is an intense pan-depolarization wave that slowly propagates in gray matter by way of contiguity and transiently disrupts neuronal function. When induced subcortically, striatal SD causes hemiparesis, hippocampal SD can trigger seizures and impact cognition, and bilateral thalamic SD can diminish consciousness. Recent data show that transgenic mice expressing familial hemiplegic migraine (FHM) type 1 mutations in voltage-gated Ca2+ channels (Cav2.1) develop mutation-specific aura-like signs after a cortical SD similar to patients with the respective mutation. These signs are associated with facilitated subcortical SD propagation. As in FHM, mice with the R192Q mutation develop pure hemiplegia associated with cortical SDs propagating into caudoputamen. S218L mice display additional signs such as seizures and coma when SD propagates into hippocampus and thalamus. In hyperexcitable FHM brains, SD may propagate between cortex and subcortical structures via permissive gray matter bridges, or originate de novo in subcortical structures, to explain unusual and severe aura signs and symptoms. Reciprocal spread and reverberating waves can explain protracted attacks.

  20. Persistent increase in oxygen consumption and impaired neurovascular coupling after spreading depression in rat neocortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard; Lauritzen, Martin

    2009-01-01

    Cortical spreading depression (CSD) is associated with a dramatic failure of brain ion homeostasis and increased energy metabolism. There is strong clinical and experimental evidence to suggest that CSD is the mechanism of migraine, and involved in progressive neuronal injury in stroke and head t...

  1. Cortical spreading depolarization increases adult neurogenesis, and alters behavior and hippocampus-dependent memory in mice.

    Science.gov (United States)

    Urbach, Anja; Baum, Eileen; Braun, Falko; Witte, Otto W

    2017-05-01

    Cortical spreading depolarizations are an epiphenomenon of human brain pathologies and associated with extensive but transient changes in ion homeostasis, metabolism, and blood flow. Previously, we have shown that cortical spreading depolarization have long-lasting consequences on the brains transcriptome and structure. In particular, we found that cortical spreading depolarization stimulate hippocampal cell proliferation resulting in a sustained increase in adult neurogenesis. Since the hippocampus is responsible for explicit memory and adult-born dentate granule neurons contribute to this function, cortical spreading depolarization might influence hippocampus-dependent cognition. To address this question, we induced cortical spreading depolarization in C57Bl/6 J mice by epidural application of 1.5 mol/L KCl and evaluated neurogenesis and behavior at two, four, or six weeks thereafter. Congruent with our previous findings in rats, we found that cortical spreading depolarization increases numbers of newborn dentate granule neurons. Moreover, exploratory behavior and object location memory were consistently enhanced. Reference memory in the water maze was virtually unaffected, whereas memory formation in the Barnes maze was impaired with a delay of two weeks and facilitated after four weeks. These data show that cortical spreading depolarization produces lasting changes in psychomotor behavior and complex, delay- and task-dependent changes in spatial memory, and suggest that cortical spreading depolarization-like events affect the emotional and cognitive outcomes of associated brain pathologies.

  2. Spreading depression sends microglia on Levy flights.

    Directory of Open Access Journals (Sweden)

    Yelena Y Grinberg

    Full Text Available Spreading depression (SD is thought to cause migraine aura, and perhaps migraine, and includes a transient loss of synaptic activity preceded and followed by increased neuronal excitability. Activated microglia influence neuronal activity and play an important role in homeostatic synaptic scaling via release of cytokines. Furthermore, enhanced neuronal function activates microglia to not only secrete cytokines but also to increase the motility of their branches, with somata remaining stationary. While SD also increases the release of cytokines from microglia, the effects on microglial movement from its synaptic activity fluctuations are unknown. Accordingly, we used time-lapse imaging of rat hippocampal slice cultures to probe for microglial movement associated with SD. We observed that in uninjured brain whole microglial cells moved. The movements were well described by the type of Lévy flight known to be associated with an optimal search pattern. Hours after SD, when synaptic activity rose, microglial cell movement was significantly increased. To test how synaptic activity influenced microglial movement, we enhanced neuronal activity with chemical long-term potentiation or LPS and abolished it with TTX. We found that microglial movement was significantly decreased by enhanced neuronal activity and significantly increased by activity blockade. Finally, application of glutamate and ATP to mimic restoration of synaptic activity in the presence of TTX stopped microglial movement that was otherwise seen with TTX. Thus, synaptic activity retains microglial cells in place and an absence of synaptic activity sends them off to influence wider expanses of brain. Perhaps increased microglial movements after SD are a long-lasting, and thus maladaptive, response in which these cells increase neuronal activity via contact or paracrine signaling, which results in increased susceptibility of larger brain areas to SD. If true, then targeting mechanisms that

  3. Stress preconditioning of spreading depression in the locust CNS.

    Directory of Open Access Journals (Sweden)

    Corinne I Rodgers

    Full Text Available Cortical spreading depression (CSD is closely associated with important pathologies including stroke, seizures and migraine. The mechanisms underlying SD in its various forms are still incompletely understood. Here we describe SD-like events in an invertebrate model, the ventilatory central pattern generator (CPG of locusts. Using K(+ -sensitive microelectrodes, we measured extracellular K(+ concentration ([K(+](o in the metathoracic neuropile of the CPG while monitoring CPG output electromyographically from muscle 161 in the second abdominal segment to investigate the role K(+ in failure of neural circuit operation induced by various stressors. Failure of ventilation in response to different stressors (hyperthermia, anoxia, ATP depletion, Na(+/K(+ ATPase impairment, K(+ injection was associated with a disturbance of CNS ion homeostasis that shares the characteristics of CSD and SD-like events in vertebrates. Hyperthermic failure was preconditioned by prior heat shock (3 h, 45 degrees C and induced-thermotolerance was associated with an increase in the rate of clearance of extracellular K(+ that was not linked to changes in ATP levels or total Na(+/K(+ ATPase activity. Our findings suggest that SD-like events in locusts are adaptive to terminate neural network operation and conserve energy during stress and that they can be preconditioned by experience. We propose that they share mechanisms with CSD in mammals suggesting a common evolutionary origin.

  4. Cortico-cortical evoked potentials for sites of early versus late seizure spread in stereoelectroencephalography.

    Science.gov (United States)

    Lega, Bradley; Dionisio, Sasha; Flanigan, Patrick; Bingaman, William; Najm, Imad; Nair, Dileep; Gonzalez-Martinez, Jorge

    2015-09-01

    Cortico-cortical evoked potentials offer the possibility of understanding connectivity within seizure networks to improve diagnosis and more accurately identify candidates for seizure surgery. We sought to determine if cortico-cortical evoked potentials and post-stimulation oscillatory changes differ for sites of EARLY versus LATE ictal spread. 37 patients undergoing stereoelectroencephalography were tested using a cortico-cortical evoked potential paradigm. All electrodes were classified according to the speed of ictal spread. EARLY spread sites were matched to a LATE spread site equidistant from the onset zone. Root-mean-square was used to quantify evoked responses and post-stimulation gamma band power and coherence were extracted and compared. Sites of EARLY spread exhibited significantly greater evoked responses after stimulation across all patients (t(36)=2.973, p=0.004). Stimulation elicited enhanced gamma band activity at EARLY spread sites (t(36)=2.61, p=0.03, FDR corrected); this gamma band oscillation was highly coherent with the onset zone. Cortico-cortical evoked potentials and post-stimulation changes in gamma band activity differ between sites of EARLY versus LATE ictal spread. The oscillatory changes can help visualize connectivity within the seizure network.

  5. Cortical spreading ischaemia is a novel process involved in ischaemic damage in patients with aneurysmal subarachnoid haemorrhage.

    Science.gov (United States)

    Dreier, Jens P; Major, Sebastian; Manning, Andrew; Woitzik, Johannes; Drenckhahn, Chistoph; Steinbrink, Jens; Tolias, Christos; Oliveira-Ferreira, Ana I; Fabricius, Martin; Hartings, Jed A; Vajkoczy, Peter; Lauritzen, Martin; Dirnagl, Ulrich; Bohner, Georg; Strong, Anthony J

    2009-07-01

    The term cortical spreading depolarization (CSD) describes a wave of mass neuronal depolarization associated with net influx of cations and water. Clusters of prolonged CSDs were measured time-locked to progressive ischaemic damage in human cortex. CSD induces tone alterations in resistance vessels, causing either transient hyperperfusion (physiological haemodynamic response) in healthy tissue; or hypoperfusion [inverse haemodynamic response = cortical spreading ischaemia (CSI)] in tissue at risk for progressive damage, which has so far only been shown experimentally. Here, we performed a prospective, multicentre study in 13 patients with aneurysmal subarachnoid haemorrhage, using novel subdural opto-electrode technology for simultaneous laser-Doppler flowmetry (LDF) and direct current-electrocorticography, combined with measurements of tissue partial pressure of oxygen (ptiO(2)). Regional cerebral blood flow and electrocorticography were simultaneously recorded in 417 CSDs. Isolated CSDs occurred in 12 patients and were associated with either physiological, absent or inverse haemodynamic responses. Whereas the physiological haemodynamic response caused tissue hyperoxia, the inverse response led to tissue hypoxia. Clusters of prolonged CSDs were measured in five patients in close proximity to structural brain damage as assessed by neuroimaging. Clusters were associated with CSD-induced spreading hypoperfusions, which were significantly longer in duration (up to 144 min) than those of isolated CSDs. Thus, oxygen depletion caused by the inverse haemodynamic response may contribute to the establishment of clusters of prolonged CSDs and lesion progression. Combined electrocorticography and perfusion monitoring also revealed a characteristic vascular signature that might be used for non-invasive detection of CSD. Low-frequency vascular fluctuations (LF-VF) (f fashion similar to that shown previously for spreading depressions of high

  6. Effects of rizatriptan on cortical spreading depression and c-Fos expression within periaqueductal grey%苯甲酸利扎曲普坦对皮质扩布性抑制及中脑导水管周围灰质c-Fos表达的影响

    Institute of Scientific and Technical Information of China (English)

    李凤鹏; 刘若卓; 姜磊; 于生元; 管维平; 石宏; 陈淑莉; 晋志高; 吴士文; 董钊; 邱恩超

    2008-01-01

    Objective To determine whether rizatriptan has an effect on cortical spreading depression (CSD) and c-Fos expression within periaqueductal grey (PAG) induced by CSD in rats. Methods The experimental SD rats were randomly divided into group A injected with KCl, group B KCl plus rizatriptan and group C NaCL The number and amplitude of CSD were recorded after KCl or NaCl injection. C-Fos positive neurons of different layer were identified by the immunohistochemical technique 2 hours after the first injection of KCl or NaCl. Results There was no CSD in group C. The number of CSD in group A ( 10.70±3.23 ) was significantly more than that in group B (6.10±2.56, t = - 3.528, P < 0.01 ). The amplitude of CSD in group A ( 17.33 (95% CI 11.45--23.11 ) mV) was significantly greater than that in group B (11.82 (95%CI 9.24--14.70) mV, Z= -4.360, P< 0.01). There were more cFos-like immnoreactive neurons in every layer in group A than in group C (P < 0.01 ) and in group B (P < 0.05 ). Conclusion Rizatriptan has an inhibitory effect on CSD, which might induce the headache through exciting the neurons in PAG.%目的 观察苯甲酸利扎曲普坦对大鼠皮质扩布性抑制(cortical spreading depression,CSD)和CSD引起中脑导水管周围灰质(periaqueduetal grey,PAG)内c-Fos表达的影响.方法 实验选用的SD大鼠随机分为3组,A组:氯化钾刺激组;B组:氯化钾刺激+苯甲酸利扎曲普坦组;C组:氯化钠刺激组.对各组大鼠使用氯化钾(或氯化钠)刺激,以观察CSD出现的个数和波幅;第1次刺激2 h后使用免疫组织化学法检测各组PAG内不同层面c-Fos阳性神经元.结果 C组未记录到CSI).A组CSD个数(10.70±3.23)较B组(6.10±2.56)显著增多(t=-3.528,P<0.01);A组CSD波幅[17.33(95%CI 11.45~23.11)mV]较B组[11.82(95%CI 9.24~14.70)mV]显著增加(Z=-4.360,P<0.01).A组各层面c-Fos阳性细胞数较B、C组显著增多(P<0.05).结论 苯甲酸利扎曲普坦对CSD有抑制作用,可使CSD引起PAG内神经元兴奋作用减弱.

  7. Depression of cortical activity in humans by mild hypercapnia.

    Science.gov (United States)

    Thesen, Thomas; Leontiev, Oleg; Song, Tao; Dehghani, Nima; Hagler, Donald J; Huang, Mingxiong; Buxton, Richard; Halgren, Eric

    2012-03-01

    The effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2 ) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event-related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level-dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH-modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity.

  8. Activity dependence of spreading depression in the locust CNS.

    Science.gov (United States)

    Spong, Kristin E; Mazzetti, Tom R; Robertson, R Meldrum

    2016-03-01

    Spreading depression (SD) is associated with large changes in extracellular ion concentrations and can be induced by impairing mechanisms of K(+) ion homeostasis. We tested activity dependence of SD in the locust model of ouabain-induced SD in the metathoracic ganglion. Wind activation of thoracic circuitry resulted in small increases of K(+) concentration that took 5-10 s to be cleared from the extracellular space. In the presence of the Na(+)/K(+)-ATPase inhibitor ouabain, wind stimulation every 30 s halved the latency to the first SD event and increased its duration. Wind stimulation was able to trigger the first event, suggesting that local activity could determine the origin of successive SD events. Perfusion with calcium-free saline blocked neural activity in the ganglion and prevented the occurrence of ouabain-induced SD. We conclude that ouabain-induced SD in the locust CNS is strongly dependent on the existing level of neural activity.

  9. Cortical Amyloid β Deposition and Current Depressive Symptoms in Alzheimer Disease and Mild Cognitive Impairment.

    Science.gov (United States)

    Chung, Jun Ku; Plitman, Eric; Nakajima, Shinichiro; Chakravarty, M Mallar; Caravaggio, Fernando; Gerretsen, Philip; Iwata, Yusuke; Graff-Guerrero, Ariel

    2016-05-01

    Depressive symptoms are frequently seen in patients with dementia and mild cognitive impairment (MCI). Evidence suggests that there may be a link between current depressive symptoms and Alzheimer disease (AD)-associated pathological changes, such as an increase in cortical amyloid-β (Aβ). However, limited in vivo studies have explored the relationship between current depressive symptoms and cortical Aβ in patients with MCI and AD. Our study, using a large sample of 455 patients with MCI and 153 patients with AD from the Alzheimer's disease Neuroimaging Initiatives, investigated whether current depressive symptoms are related to cortical Aβ deposition. Depressive symptoms were assessed using the Geriatric Depression Scale and Neuropsychiatric Inventory-depression/dysphoria. Cortical Aβ was quantified using positron emission tomography with the Aβ probe(18)F-florbetapir (AV-45).(18)F-florbetapir standardized uptake value ratio (AV-45 SUVR) from the frontal, cingulate, parietal, and temporal regions was estimated. A global AV-45 SUVR, defined as the average of frontal, cingulate, precuneus, and parietal cortex, was also used. We observed that current depressive symptoms were not related to cortical Aβ, after controlling for potential confounds, including history of major depression. We also observed that there was no difference in cortical Aβ between matched participants with high and low depressive symptoms, as well as no difference between matched participants with the presence and absence of depressive symptoms. The association between depression and cortical Aβ deposition does not exist, but the relationship is highly influenced by stressful events in the past, such as previous depressive episodes, and complex interactions of different pathways underlying both depression and dementia.

  10. Regional cortical gray matter thickness differences associated with type 2 diabetes and major depression

    Science.gov (United States)

    Ajilore, Olusola; Narr, Katherine; Rosenthal, Jonah; Pham, Daniel; Hamilton, Liberty; Watari, Kecia; Elderkin-Thompson, Virginia; Darwin, Christine; Toga, Arthur; Kumar, Anand

    2010-01-01

    Objective The purpose of this study was to examine the effect of type 2 diabetes with major depression on cortical gray matter using magnetic resonance imaging and cortical pattern matching techniques. We hypothesized that diabetic subjects and depressed diabetic subjects would demonstrate decreased cortical gray matter thickness in prefrontal areas as compared to healthy control subjects. Methods Patients with type 2 diabetes (n=26) and patients diabetes and major depression (n=26) were compared with healthy controls (n=20). Gray matter thickness across the entire cortex was measured using cortical pattern matching methods. Results All subjects with diabetes demonstrated decreased cortical gray matter thickness in the left anterior cingulate region. Additionally, depressed diabetic subjects showed significant cortical gray matter decreases in bilateral prefrontal areas compared with healthy controls. Correlations between clinical variables and cortical gray matter thickness revealed a significant negative relationship with cerebrovascular risk factors across all three groups, most consistently in the left dorsomedial prefrontal cortex. A significant positive relationship between performance on attention and executive function tasks and cortical gray matter thickness predominately in left hemisphere regions was also seen across all subjects. Conclusion Depression and diabetes are associated with significant cortical gray matter thinning in medial prefrontal areas. PMID:20832254

  11. Fetal exposure to maternal depressive symptoms is associated with cortical thickness in late childhood.

    Science.gov (United States)

    Sandman, Curt A; Buss, Claudia; Head, Kevin; Davis, Elysia Poggi

    2015-02-15

    Maternal depression is one of the most common prenatal complications. The consequences of fetal exposure to maternal depression are poorly understood. The aim of this study is to examine the association between fetal exposure to maternal depressive symptoms and cortical thickness in children 6-9 years old. A prospective, longitudinal study of maternal depressive symptoms at 19, 25, and 31 weeks' gestation was followed by acquisition of a structural magnetic resonance imaging scan in 81 children (age, 86.1 ± 9.9 months). Significant (p < .01) cortical thinning in children primarily in the right frontal lobes was associated with exposure to prenatal maternal depression. The strongest association was at 25 weeks' gestation; exposure to maternal depression at 25 gestational weeks was associated with cortical thinning in 19% of the whole cortex and 24% of the frontal lobes, primarily in the right superior, medial orbital, and frontal pole regions of the prefrontal cortex (p < .01). The significant association between prenatal maternal depression and child externalizing behavior (p < .05) was mediated by cortical thinning in prefrontal areas of the right hemisphere. The pattern of cortical thinning in children exposed to prenatal maternal depression is similar to patterns in depressed patients and in individuals with risk for depression. Exposure to prenatal depression coupled with subsequent cortical thinning was associated with presence of externalizing behavior in preadolescent children and may be prodromal markers of risk for dysphoria. Vulnerability to prenatal influences at 25 gestational weeks may result from the enormous growth and dramatic structural changes in the nervous system. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  12. Early malnutrition attenuates the impairing action of naloxone on spreading depression in young rats.

    Science.gov (United States)

    Guedes, Rubem Carlos Araújo; Rocha-de-Melo, Ana Paula; de Lima, Kalina Rimena; de Albuquerque, Juliana da Mota Silveira; Francisco, Elian da Silva

    2013-07-01

    Malnutrition early in life can disrupt neurotransmitter systems in the brain, affecting its electrophysiological function. The opioid receptor antagonist naloxone can affect the electroencephalogram (EEG) and behavior in animals and humans, and patients under drug-abuse treatment use it as a therapy. The goal of this work in the rat is to determine whether malnutrition early in life modulates the action of naloxone on the excitability-related phenomenon known as cortical spreading depression (CSD). Malnutrition was induced by feeding the dams during the gestation and lactation with a low-protein diet (8% protein). Their male pups received a single daily subcutaneous injection of naloxone (10 mg/kg/day) from the 7th to the 28th postnatal day, and were subsequently (30-40 days of life) submitted to a 4-hours CSD recording session, with electrodes at two points at a fixed distance apart on the parietal cortical surface. Compared to well-nourished rats receiving a 23% protein diet, malnourished animals displayed lower body weights and higher CSD velocities of propagation, confirming the facilitating effect of malnutrition on CSD. Naloxone treatment reduced in well-nourished rats the CSD propagation velocity, as compared to saline-injected controls. In contrast, the naloxone effect was less intense in the malnourished condition, and the CSD velocity difference between malnourished-naloxone and malnourished-saline groups did not reach statistical significance. Data strongly support the involvement of opioid-based mechanisms in excitability-related neural processes, which probably influence CSD propagation, and indicate that early malnutrition attenuates the impairing action of naloxone on CSD.

  13. Microemboli may link spreading depression, migraine aura, and patent foramen ovale.

    Science.gov (United States)

    Nozari, Ala; Dilekoz, Ergin; Sukhotinsky, Inna; Stein, Thor; Eikermann-Haerter, Katharina; Liu, Christina; Wang, Yumei; Frosch, Matthew P; Waeber, Christian; Ayata, Cenk; Moskowitz, Michael A

    2010-02-01

    Patent foramen ovale and pulmonary arteriovenous shunts are associated with serious complications such as cerebral emboli, stroke, and migraine with aura. The pathophysiological mechanisms that link these conditions are unknown. We aimed to establish a mechanism linking microembolization to migraine aura in an experimental animal model. We introduced particulate or air microemboli into the carotid circulation in mice to determine whether transient microvascular occlusion, insufficient to cause infarcts, triggered cortical spreading depression (CSD), a propagating slow depolarization that underlies migraine aura. Air microemboli reliably triggered CSD without causing infarction. Polystyrene microspheres (10 microm) or cholesterol crystals (<70 microm) triggered CSD in 16 of 28 mice, with 60% of the mice (40% of those with CSD) showing no infarcts or inflammation on detailed histological analysis of serial brain sections. No evidence of injury was detected on magnetic resonance imaging examination (9.4T; T2 weighted) in 14 of 15 selected animals. The occurrence of CSD appeared to be related to the magnitude and duration of flow reduction, with a triggering mechanism that depended on decreased brain perfusion but not sustained tissue damage. In a mouse model, microemboli triggered CSD, often without causing microinfarction. Paradoxical embolization then may link cardiac and extracardiac right-to-left shunts to migraine aura. If translatable to humans, a subset of migraine auras may belong to a spectrum of hypoperfusion disorders along with transient ischemic attacks and silent infarcts.

  14. Cortical spreading ischaemia is a novel process involved in ischaemic damage in patients with aneurysmal subarachnoid haemorrhage

    DEFF Research Database (Denmark)

    Dreier, Jens P; Major, Sebastian; Manning, Andrew

    2009-01-01

    -invasive detection of CSD. Low-frequency vascular fluctuations (LF-VF) (f imaging methods, are determined by the brain's resting neuronal activity. CSD provides a depolarization block of the resting activity, recorded electrophysiologically as spreading depression of high...... the differentiation of progressive ischaemia and repair phases in a fashion similar to that shown previously for spreading depressions of high-frequency-electrocorticography activity. In conclusion, it is suggested that (i) CSI is a novel human disease mechanism associated with lesion development and a potential...

  15. Modulatory Effects of Dopamine D2 Receptors on Spreading Depression in Rat Somatosensory Neocortex

    OpenAIRE

    2014-01-01

    Introduction: Spreading depression (SD) is a propagating wave of depolarization followed by depression of the neuroglial activities and can modulate extracellular dopamine concentrations in the neocortex. It has been shown that the dopaminergic system plays a role in migraine. SD has been suggested as a critical phenomenon in the pathophysiology of migraine. The aim of this study was to investigate the effect of dopamine D2 receptors on the characteristic features of SD in rat neocortical tis...

  16. Increased cortical-limbic anatomical network connectivity in major depression revealed by diffusion tensor imaging.

    Directory of Open Access Journals (Sweden)

    Peng Fang

    Full Text Available Magnetic resonance imaging studies have reported significant functional and structural differences between depressed patients and controls. Little attention has been given, however, to the abnormalities in anatomical connectivity in depressed patients. In the present study, we aim to investigate the alterations in connectivity of whole-brain anatomical networks in those suffering from major depression by using machine learning approaches. Brain anatomical networks were extracted from diffusion magnetic resonance images obtained from both 22 first-episode, treatment-naive adults with major depressive disorder and 26 matched healthy controls. Using machine learning approaches, we differentiated depressed patients from healthy controls based on their whole-brain anatomical connectivity patterns and identified the most discriminating features that represent between-group differences. Classification results showed that 91.7% (patients=86.4%, controls=96.2%; permutation test, p<0.0001 of subjects were correctly classified via leave-one-out cross-validation. Moreover, the strengths of all the most discriminating connections were increased in depressed patients relative to the controls, and these connections were primarily located within the cortical-limbic network, especially the frontal-limbic network. These results not only provide initial steps toward the development of neurobiological diagnostic markers for major depressive disorder, but also suggest that abnormal cortical-limbic anatomical networks may contribute to the anatomical basis of emotional dysregulation and cognitive impairments associated with this disease.

  17. Cortical shape and curvedness analysis of structural deficits in remitting and non-remitting depression.

    Directory of Open Access Journals (Sweden)

    Yuan-Lin Liao

    Full Text Available In morphometric neuroimaging studies, the relationship between brain structural changes and the antidepressant treatment response in patients with major depressive disorder has been explored to search depression-trait biomarkers. Although patients were treated with serotonin-related drugs, whether the same treatment resulted in remission and non-remission in depressed patients is currently under investigation. We recruited 25 depressed patients and 25 healthy controls and acquired volumetric magnetic resonance imaging of each participant. We used the shape index and curvedness to classify cortical shapes and quantify shape complexities, respectively, in studying the pharmacological effect on brain morphology. The results showed that different regions of structural abnormalities emerged between remitting and non-remitting patients when contrasted with healthy controls. In addition to comparing structural metrics in each cortical parcellation, similar to the traditional voxel-based morphometric method, we highlighted the importance of structural integrity along the serotonin pathway in response to medication treatment. We discovered that disrupted serotonin-related cortical regions might cause non-remission to antidepressant treatment from a pharmacological perspective. The anomalous areas manifested in non-remitting patients were mainly in the frontolimbic areas, which can be used to differentiate remitting from non-remitting participants before medication treatment. Because non-remission is the failure to respond to treatment with serotonin-related drugs, our method may help clinicians choose appropriate medications for non-remitting patients.

  18. The Relationship Between Cortical Inhibition and Electroconvulsive Therapy in the Treatment of Major Depressive Disorder.

    Science.gov (United States)

    Voineskos, Daphne; Levinson, Andrea J; Sun, Yinming; Barr, Mera S; Farzan, Faranak; Rajji, Tarek K; Fitzgerald, Paul B; Blumberger, Daniel M; Daskalakis, Zafiris J

    2016-12-09

    Dysfunctional cortical inhibition (CI) is postulated as a key neurophysiological mechanism in major depressive disorder. Electroconvulsive therapy (ECT) is the treatment of choice for resistant depression and ECT has been associated with enhanced CI. The objective of this study was to evaluate the relationship between CI and ECT response in resistant depression. Twenty-five patients with treatment resistant depression underwent an acute course of ECT. CI was indexed by the cortical silent period (CSP) and short-interval cortical inhibition (SICI), through TMS-EMG. CI and clinical response was measured prior to beginning an acute ECT course and within 48 hours of the last ECT treatment in the course. Clinical response to ECT was assessed by HDRS-17 before and after an acute course of ECT. We found that there was a significant difference in CSP at baseline between responder and non-responder groups (p = 0.044). Baseline CSP predicted therapeutic response to ECT with sensitivity of 80% and specificity of 60%. There were no changes in CSP or SICI after administration of the ECT course. Our findings suggest that duration of pre-treatment CSP may be a useful predictor of therapeutic response to ECT in patients with TRD.

  19. Brimonidine tartrate effect on retinal spreading depression depends on Müller cells

    OpenAIRE

    Vinícius Vanzan Pimentel de Oliveira; Marcio Penha Morterá Rodrigues; Adroaldo de Alencar; Sebastião Cronemberger; Nassim Calixto; Adalmir Morterá Dantas

    2014-01-01

    Objective: Demonstrate the Brimonidine effect over Retinal Spreading Depression (SD). Brimonidine is an alpha-2–adrenergic receptor agonist, used in the management of glaucoma. Alpha2-agonists have been shown to be neuroprotective in various experimental models, however the molecular and cellular targets leading to these actions are still poorly defined. The SD of neuronal electric activity is a wave of cellular massive sustained depolarization that damages the nervous tissue. Local tra...

  20. Spreading Depressions as Secondary Insults after Traumatic Injury to the Human Brain

    Science.gov (United States)

    2012-09-01

    aneurysmal subarachnoid haemorrhage, depolarisations with depression periods longer than 10 min had worse outcomes at discharge and the rate of...is a novel process involved in ischaemic damage in patients with aneurysmal subarachnoid haemorrhage. Brain 2009; 132: 1866–81. 17 Nakamura H, Strong... Pediatrics ), Harvard Medical School and Children’s Hospital Boston, Boston, MA, USA 1 Hartings JA, Bullock MR, Okonkwo DO, et al. Spreading

  1. An Exploratory Study of Spectroscopic Glutamatergic Correlates of Cortical Excitability in Depressed Adolescents

    Directory of Open Access Journals (Sweden)

    Charles P. Lewis

    2016-11-01

    Full Text Available Introduction: Transcranial magnetic stimulation (TMS research has suggested dysfunction in cortical glutamatergic systems in depression, while proton magnetic resonance spectroscopy (1H-MRS studies have demonstrated deficits in concentrations of glutamatergic metabolites in depressed individuals in several cortical regions, including the anterior cingulate cortex (ACC. However, few studies have combined TMS and MRS methods to examine relationships between glutamatergic neurochemistry and excitatory and inhibitory neural functions, and none have utilized TMS-MRS methodology in clinical populations or in youth. This exploratory study aimed to examine relationships between TMS measures of cortical excitability and inhibition and concentrations of glutamatergic metabolites as measured by 1H-MRS in depressed adolescents. Methods: Twenty-four children and adolescents (aged 11-18 years with depressive symptoms underwent TMS testing, which included measures of the resting motor threshold (RMT, cortical silent period (CSP, short-interval intracortical inhibition (SICI, and intracortical facilitation (ICF. Fourteen participants from the same sample also completed 1H-MRS in a 3 T MRI scanner after TMS testing. Glutamate + glutamine (Glx concentrations were measured in medial ACC and left primary motor cortex voxels with a TE-optimized PRESS sequence. Metabolite concentrations were corrected for cerebrospinal fluid after tissue segmentation. Pearson product-moment and Spearman rank-order correlations were calculated to assess relationships between TMS measures and Glx. Results: In the left primary motor cortex voxel, Glx had a significant positive correlation with the RMT. In the medial ACC voxel, Glx had significant positive correlations with ICF at the 10-ms and 20-ms ISIs.Conclusions: These preliminary data implicate glutamate in cortical excitatory processes measured by TMS. Limitations included small sample size, lack of healthy control comparators

  2. Measurement of distinctive features of cortical spreading depolarizations with different MRI contrasts

    NARCIS (Netherlands)

    Umesh Rudrapatna, S.; Hamming, Arend M.; Wermer, Marieke J H; van der Toorn, A; Dijkhuizen, Rick M.

    2015-01-01

    Growing clinical evidence suggests critical involvement of spreading depolarizations (SDs) in the pathophysiology of neurological disorders such as migraine and stroke. MRI provides powerful tools to detect and assess co-occurring cerebral hemodynamic and cellular changes during SDs. This study

  3. Measurement of distinctive features of cortical spreading depolarizations with different MRI contrasts

    NARCIS (Netherlands)

    Umesh Rudrapatna, S.; Hamming, Arend M.; Wermer, Marieke J H; van der Toorn, A; Dijkhuizen, Rick M.

    2015-01-01

    Growing clinical evidence suggests critical involvement of spreading depolarizations (SDs) in the pathophysiology of neurological disorders such as migraine and stroke. MRI provides powerful tools to detect and assess co-occurring cerebral hemodynamic and cellular changes during SDs. This study repo

  4. Spreading depression is facilitated in adult rats previously submitted to short episodes of malnutrition during the lactation period

    Directory of Open Access Journals (Sweden)

    Rocha-de-Melo A.P.

    1997-01-01

    Full Text Available Lactating rat dams were submitted to short episodes (1, 2 or 3 weeks of nutritional restriction by receiving the "regional basic diet" (RBD, with 8% protein of low-income human populations of Northeast Brazil. Their pups were then studied regarding the developmental effects on body and brain weights. When the rats reached adulthood, cortical susceptibility to the phenomenon of spreading depression (SD was evaluated by performing electrophysiological recordings on the surface of the cerebral cortex. SD was elicited at 20-min intervals by applying 2% KCl for 1 min to a site on the frontal cortex and its occurrence was monitored at 2 sites in the parietal region by recording the electrocorticogram and the slow potential change of SD. When compared to control rats fed a commercial diet with 23% protein, early malnourished rats showed deficits in body and brain weights (10% to 60% and 3% to 15%, respectively, as well as increases in velocity of SD propagation (10% to 20%. These effects were directly related to the duration of maternal dietary restriction, with pups malnourished for 2 or 3 weeks presenting more intense weight and SD changes than those malnourished for 1 week. The effects of 1-week restrictions on SD were less evident in the pups malnourished during the second week of lactation and were more evident in pups receiving the RBD during the third week. The results indicate that short episodes of early malnutrition during the suckling period can affect body and brain development, as well as the cortical susceptibility to SD during adulthood. The data also suggest that the third week of lactation is the period during which the brain is most sensitive to malnutrition, concerning the effects on SD

  5. Multi-dimensional modulations of alpha and gamma cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder

    NARCIS (Netherlands)

    Schoenberg, P.L.; Speckens, A.E.M.

    2015-01-01

    To illuminate candidate neural working mechanisms of Mindfulness-Based Cognitive Therapy (MBCT) in the treatment of recurrent depressive disorder, parallel to the potential interplays between modulations in electro-cortical dynamics and depressive symptom severity and self-compassionate experience.

  6. Cortical excitability is not depressed in movement-modulated stretch response of human thumb flexor.

    Science.gov (United States)

    Wallace, C J; Miles, T S

    2001-08-01

    There is strong evidence that the predominant pathway of the long-latency stretch reflex for flexor pollicis longus crosses the motor cortex. This reflex response is diminished during active thumb movements. We tested the hypothesis that this could be due to a decrease in the excitability of the transcortical component during movement. During isometric, concentric and eccentric thumb movements, transcranial magnetic stimulation (TMS) of the motor cortex was given at a time when the reflex signal was traversing the motor cortex. TMS was also given earlier in separate runs when the signal was traversing the spinal cord under each of the three contractile conditions. The electromyogram was analysed for non-linear summation between stretch responses and the potential evoked by the cortical stimulus. The response to TMS alone was uniform across the three types of contraction, and the lack of cortical involvement in the short-latency reflex was confirmed. The TMS-evoked response summed in a non-linear manner with the long-latency reflex response, confirming that the excitability of the motor cortex was increased as the reflex signal passed through it. The long-latency response was markedly depressed during isotonic compared with isometric contractions. However, the non-linear summation was not greater during the isometric contractions. Thus, the depressed reflex responses during isotonic movements do not stem from reduced motor cortical responsiveness or afferent input to the transcortical pathway, and may instead reflect modulation of cutaneous reflexes during isotonic contractions.

  7. [Cortical spreading depolarization phenomena in patients with traumatic and ischemic brain injuries. Results of a pilot study].

    Science.gov (United States)

    Sueiras, M; Sahuquillo, J; García-López, B; Sánchez-Guerrero, Á; Poca, M A; Santamarina, E; Riveiro, M; Fabricius, M; Strong, A J

    2014-10-01

    To determine the frequency and duration of cortical spreading depolarization (CSD) and CSD-like episodes in patients with traumatic brain injury (TBI) and malignant middle cerebral artery infarction (MMCAI) requiring craniotomy. A descriptive observational study was carried out during 19 months. Neurocritical patients. Sixteen patients were included: 9 with MMCAI and 7 with moderate or severe TBI, requiring surgical treatment. A 6-electrode subdural electrocorticographic (ECoG) strip was placed onto the perilesional cortex. An analysis was made of the time profile and the number and duration of CSD and CSD-like episodes recorded from the ECoGs. Of the 16 patients enrolled, 9 presented episodes of CSD or CSD-like phenomena, of highly variable frequency and duration. Episodes of CSD and CSD-like phenomena are frequently detected in the ischemic penumbra and/or traumatic cortical regions of patients with MMCAI who require decompressive craniectomy or of patients with contusional TBI. Copyright © 2013 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  8. Use of cortical stimulation in neuropathic pain, tinnitus, depression, and movement disorders.

    Science.gov (United States)

    Panov, Fedor; Kopell, Brian Harris

    2014-07-01

    Medical treatment must strike a balance between benefit and risk. As the field of neuromodulation develops, decreased invasiveness, in combination with maintenance of efficacy, has become a goal. We provide a review of the history of cortical stimulation from its origins to the current state. The first part discusses neuropathic pain and the nonpharmacological treatment options used. The second part covers transitions to tinnitus, believed by many to be another deafferentation disorder, its classification, and treatment. The third part focuses on major depression. The fourth section concludes with the discussion of the use of cortical stimulation in movement disorders. Each part discusses the development of the field, describes the current care protocols, and suggests future avenues for research needed to advance neuromodulation.

  9. Impact of Depression, Fatigue, and Global Measure of Cortical Volume on Cognitive Impairment in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Domenica Nunnari

    2015-01-01

    Full Text Available Objective. To investigate the influence of demographic and clinical variables, such as depression, fatigue, and quantitative MRI marker on cognitive performances in a sample of patients affected by multiple sclerosis (MS. Methods. 60 MS patients (52 relapsing remitting and 8 primary progressive underwent neuropsychological assessments using Rao’s Brief Repeatable Battery of Neuropsychological Tests (BRB-N, the Beck Depression Inventory-second edition (BDI-II, and the Fatigue Severity Scale (FSS. We performed magnetic resonance imaging to all subjects using a 3 T scanner and obtained tissue-specific volumes (normalized brain volume and cortical brain volume. We used Student’s t-test to compare depressed and nondepressed MS patients. Finally, we performed a multivariate regression analysis in order to assess possible predictors of patients’ cognitive outcome among demographic and clinical variables. Results. 27.12% of the sample (16/59 was cognitively impaired, especially in tasks requiring attention and information processing speed. From between group comparison, we find that depressed patients had worse performances on BRB-N score, greater disability and disease duration, and brain volume decrease. According to multiple regression analysis, the BDI-II score was a significant predictor for most of the neuropsychological tests. Conclusions. Our findings suggest that the presence of depressive symptoms is an important determinant of cognitive performance in MS patients.

  10. Linking a genetic defect in migraine to spreading depression in a computational model

    Directory of Open Access Journals (Sweden)

    Markus A. Dahlem

    2014-05-01

    Full Text Available Familial hemiplegic migraine (FHM is a rare subtype of migraine with aura. A mutation causing FHM type 3 (FHM3 has been identified in SCN1A encoding the Nav1.1 Na+ channel. This genetic defect affects the inactivation gate. While the Na+ tail currents following voltage steps are consistent with both hyperexcitability and hypoexcitability, in this computational study, we investigate functional consequences beyond these isolated events. Our extended Hodgkin–Huxley framework establishes a connection between genotype and cellular phenotype, i.e., the pathophysiological dynamics that spans over multiple time scales and is relevant to migraine with aura. In particular, we investigate the dynamical repertoire from normal spiking (milliseconds to spreading depression and anoxic depolarization (tens of seconds and show that FHM3 mutations render gray matter tissue more vulnerable to spreading depression despite opposing effects associated with action potential generation. We conclude that the classification in terms of hypoexcitability vs. hyperexcitability is too simple a scheme. Our mathematical analysis provides further basic insight into also previously discussed criticisms against this scheme based on psychophysical and clinical data.

  11. Effects of cigarette smoking on cortical thickness in major depressive disorder.

    Science.gov (United States)

    Zorlu, Nabi; Cropley, Vanessa Louise; Zorlu, Pelin Kurtgoz; Delibas, Dursun Hakan; Adibelli, Zehra Hilal; Baskin, Emel Pasa; Esen, Özgür Sipahi; Bora, Emre; Pantelis, Christos

    2017-01-01

    Findings of surface-based morphometry studies in major depressive disorder (MDD) are still inconsistent. Given that cigarette smoking is highly prevalent in MDD and has documented negative effects on the brain, it is possible that some of the inconsistencies may be partly explained by cigarette use. The aim of the current study was to examine the influence of cigarette smoking on brain structure in MDD. 50 MDD patients (25 smokers and 25 non-smokers) and 22 age, education, gender and BMI matched non-smoker healthy controls underwent structural magnetic resonance imaging. Thickness and area of the cortex were measured using surface-based morphometry implemented with Freesurfer (v5.3.0). The non-smoker MDD patients had significantly increased cortical thickness, including in the left temporal cortex (p smoked compared to non-smoking patients in regions that overlapped with the regions found to be increased in non-smoking patients in comparison to controls. Non-smoker MDD patients had increased surface area in the right lateral occipital cortex (p = 0.009). We did not find any region where cortical thickness or surface area significantly differed between controls and either smoker MDD patients or all MDD patients. The findings of the current study suggest that cigarette smoking is associated with cortical thinning in regions found to be increased in patients with MDD. However, these results should be considered preliminary due to methodological limitations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Temporal alteration of spreading depression by the glycine transporter type-1 inhibitors NFPS and Org-24461 in chicken retina.

    Science.gov (United States)

    Kertesz, Szabolcs; Szabo, Geza; Udvari, Szabolcs; Levay, Gyorgy; Matyus, Peter; Harsing, Laszlo G

    2013-01-25

    We used isolated chicken retina to induce spreading depression by the glutamate receptor agonist N-methyl-d-aspartate. The N-methyl-d-aspartate-induced latency time of spreading depression was extended by the glycine(B) binding site competitive antagonist 7-chlorokynurenic acid. Addition of the glycine transporter type-1 inhibitors NFPS and Org-24461 reversed the inhibitory effect of 7-chlorokynurenic acid on N-methyl-d-aspartate-evoked spreading depression. The glycine uptake inhibitory activity of Org-24461, NFPS, and some newly synthesized analogs of NFPS was determined in CHO cells stably expressing human glycine transporter type-1b isoform. Compounds, which failed to inhibit glycine transporter type-1, also did not have effect on retinal spreading depression. These experiments indicate that the spreading depression model in chicken retina is a useful in vitro test to determine activity of glycine transporter type-1 inhibitors. In addition, our data serve further evidence for the role of glycine transporter type-1 in retinal neurotransmission and light processing.

  13. Anxious/Depressed Symptoms are Linked to Right Ventromedial Prefrontal Cortical Thickness Maturation in Healthy Children and Young Adults

    Science.gov (United States)

    Ducharme, Simon; Albaugh, Matthew D.; Hudziak, James J.; Botteron, Kelly N.; Nguyen, Tuong-Vi; Truong, Catherine; Evans, Alan C.; Karama, Sherif; Ball, William S.; Byars, Anna Weber; Schapiro, Mark; Bommer, Wendy; Carr, April; German, April; Dunn, Scott; Rivkin, Michael J.; Waber, Deborah; Mulkern, Robert; Vajapeyam, Sridhar; Chiverton, Abigail; Davis, Peter; Koo, Julie; Marmor, Jacki; Mrakotsky, Christine; Robertson, Richard; McAnulty, Gloria; Brandt, Michael E.; Fletcher, Jack M.; Kramer, Larry A.; Yang, Grace; McCormack, Cara; Hebert, Kathleen M.; Volero, Hilda; Botteron, Kelly; McKinstry, Robert C.; Warren, William; Nishino, Tomoyuki; Almli, C. Robert; Todd, Richard; Constantino, John; McCracken, James T.; Levitt, Jennifer; Alger, Jeffrey; O'Neil, Joseph; Toga, Arthur; Asarnow, Robert; Fadale, David; Heinichen, Laura; Ireland, Cedric; Wang, Dah-Jyuu; Moss, Edward; Zimmerman, Robert A.; Bintliff, Brooke; Bradford, Ruth; Newman, Janice; Evans, Alan C.; Arnaoutelis, Rozalia; Pike, G. Bruce; Collins, D. Louis; Leonard, Gabriel; Paus, Tomas; Zijdenbos, Alex; Das, Samir; Fonov, Vladimir; Fu, Luke; Harlap, Jonathan; Leppert, Ilana; Milovan, Denise; Vins, Dario; Zeffiro, Thomas; Van Meter, John; Lange, Nicholas; Froimowitz, Michael P.; Botteron, Kelly; Almli, C. Robert; Rainey, Cheryl; Henderson, Stan; Nishino, Tomoyuki; Warren, William; Edwards, Jennifer L.; Dubois, Diane; Smith, Karla; Singer, Tish; Wilber, Aaron A.; Pierpaoli, Carlo; Basser, Peter J.; Chang, Lin-Ching; Koay, Chen Guan; Walker, Lindsay; Freund, Lisa; Rumsey, Judith; Baskir, Lauren; Stanford, Laurence; Sirocco, Karen; Gwinn-Hardy, Katrina; Spinella, Giovanna; McCracken, James T.; Alger, Jeffry R.; Levitt, Jennifer; O'Neill, Joseph

    2014-01-01

    The relationship between anxious/depressed traits and neuromaturation remains largely unstudied. Characterizing this relationship during healthy neurodevelopment is critical to understanding processes associated with the emergence of child/adolescent onset mood/anxiety disorders. In this study, mixed-effects models were used to determine longitudinal cortical thickness correlates of Child Behavior Checklist (CBCL) and Young Adult Self Report Anxious/Depressed scores in healthy children. Analyses included 341 subjects from 4.9 to 22.3 year-old with repeated MRI at up to 3 time points, at 2-year intervals (586 MRI scans). There was a significant “CBCL Anxious/Depressed by Age” interaction on cortical thickness in the right ventromedial prefrontal cortex (vmPFC), including the medial orbito-frontal, gyrus rectus, and subgenual anterior cingulate areas. Anxious/Depressed scores were negatively associated with thickness at younger ages (<9 years), but positively associated with thickness at older ages (15–22 years), with the shift in polarity occurring around age 12. This was secondary to a slower rate of vmPFC cortical thinning in subjects with higher scores. In young adults (18–22 years), Anxious/Depressed scores were also positively associated with precuneus/posterior cingulate cortical thickness. Potential neurobiological mechanisms underlying this maturation pattern are proposed. These results demonstrate the dynamic impact of age on relations between vmPFC and negative affect in the developing brain. PMID:23749874

  14. 抑郁症在中国的传播%The Spread of Depression in China

    Institute of Scientific and Technical Information of China (English)

    何伶俐; 汪新建

    2012-01-01

    One with the same feelings of depression, physical and mental fatigue, not interested in social activities in the linked States is diagnosed as depression, while in China it would be neurasthenia. But in China with the spread of diagnostic criteria of Western psychiatry, the increasing attention and reports about depression from mass media, the expansion of Western pharmaceutical market in China, depression is more and more accepted in Chinese public. This is not only because the significant impact of Western culture and its diagnostic criteria for mental illness in china, but also the promoted result by the vested interests.%同样是心情压抑、身心疲劳、对社会活动没有兴趣,在美国被界定为抑郁症,而在中国则被诊断为神经衰弱.但随着西方精神病学及诊断标准在中国的传播与发展、大众传媒的关注与宣传、西方医药市场在中国的立足与扩张,抑郁症也越来越被中国公众接受.这既是西方文化及其精神疾病诊断标准在全球化的背景和趋势下对中国的扩张,亦是某些获利者 在背后推动的结果.

  15. Early cortical biomarkers of longitudinal transcutaneous vagus nerve stimulation treatment success in depression.

    Science.gov (United States)

    Fang, Jiliang; Egorova, Natalia; Rong, Peijing; Liu, Jun; Hong, Yang; Fan, Yangyang; Wang, Xiaoling; Wang, Honghong; Yu, Yutian; Ma, Yunyao; Xu, Chunhua; Li, Shaoyuan; Zhao, Jingjun; Luo, Man; Zhu, Bing; Kong, Jian

    2017-01-01

    Transcutaneous vagus nerve stimulation (tVNS), a non-invasive method of brain stimulation through the auricular branch of the vagus nerve, has shown promising results in treating major depressive disorder (MDD) in several pilot studies. However, the neural mechanism by which the effect on depression might be achieved has not been fully investigated, with only a few neuroimaging studies demonstrating tVNS-induced changes in the brains of healthy volunteers. Identifying specific neural pathways, which are influenced by tVNS compared with sham in depressed individuals, as well as determining neurobiomarkers of tVNS treatment success are needed to advance the application of tVNS for MDD. In order to address these questions, we measured fMRI brain activity of thirty-eight depressed patients assigned to undergo tVNS (n = 17) or sham (n = 21) treatment for 4 weeks, during the first stimulation session. The results showed significant fMRI signal increases in the left anterior insula, revealed by a direct comparison of tVNS and sham stimulation. Importantly, the insula activation level during the first stimulation session in the tVNS group was significantly associated with the clinical improvement at the end of the four-week treatment, as indicated by the Hamilton Depression Rating Scale (HAM-D) score. Our findings suggest that anterior insula fMRI activity could serve as a potential cortical biomarker and an early predictor of tVNS longitudinal treatment success.

  16. Ignition's glow: Ultra-fast spread of global cortical activity accompanying local "ignitions" in visual cortex during conscious visual perception.

    Science.gov (United States)

    Noy, N; Bickel, S; Zion-Golumbic, E; Harel, M; Golan, T; Davidesco, I; Schevon, C A; McKhann, G M; Goodman, R R; Schroeder, C E; Mehta, A D; Malach, R

    2015-09-01

    ) with an ultra-fast spread of signals of lower magnitude that invaded selected sites throughout fronto-parietal cortical areas. Our results are compatible with local models in demonstrating a clear task-dependence of the 300 ms fronto-parietal activation. However, they also reveal a more global component of low-magnitude and poor content selectivity that rapidly spreads into fronto-parietal sites. The precise functional role of this global "glow" remains to be elucidated.

  17. Recording, analysis, and interpretation of spreading depolarizations in neurointensive care

    DEFF Research Database (Denmark)

    Dreier, Jens P; Fabricius, Martin; Ayata, Cenk

    2016-01-01

    recorded during multimodal neuromonitoring in neurocritical care as a causal biomarker providing a diagnostic summary measure of metabolic failure and excitotoxic injury. Focal ischemia causes spreading depolarization within minutes. Further spreading depolarizations arise for hours to days due to energy...... electrocorticographic monitoring affords even remote detection of injury because spreading depolarizations propagate widely from ischemic or metabolically stressed zones; characteristic patterns, including temporal clusters of spreading depolarizations and persistent depression of spontaneous cortical activity, can...

  18. Recent progress in migraine pathophysiology: role of cortical spreading depression and magnetic resonance imaging

    NARCIS (Netherlands)

    Bhaskar, S.; Saeidi, K.; Borhani, P.; Amiri, H.

    2013-01-01

    Migraine is characterised by debilitating pain, which affects the quality of life in affected patients in both the western and the eastern worlds. The purpose of this article is to give a detailed outline of the pathophysiology of migraine pain, which is one of the most confounding pathologies among

  19. Dissociation of glutamate and cortical thickness is restricted to regions subserving trait but not state markers in major depressive disorder

    NARCIS (Netherlands)

    Li, Meng; Metzger, Coraline D.; Li, Wenjing; Safron, Adam; van Tol, Marie-Jose; Lord, Anton; Krause, Anna Linda; Borchardt, Viola; Dou, Weiqiang; Genz, Axel; Heinze, Hans-Jochen; He, Huiguang; Walter, Martin

    2014-01-01

    Background: The anterior cingulate cortex (ACC) plays an important role in the neuropathology of major depressive disorder (MDD). So far, the effect of local cortical alteration on metabolites in multiple subdivisions of ACC has not been studied. We aimed to investigate structural and biochemical ch

  20. Lithium/nutrition interaction in the brain: a single lithium administration impairs spreading depression in malnourished, but not in well-nourished rats.

    Science.gov (United States)

    de Aguiar, Márlison José Lima; de Aguiar, Cilene Rejane Ramos Alves; Guedes, Rubem Carlos Araújo

    2011-07-01

    Lithium salts exert electrophysiological and behavioral effects in animals and humans and have been used clinically in the treatment of bipolar disorders. Little is known about the lithium/nutrition interaction in the developing brain. This work aimed to determine, in adult rats, whether treatment with a single dose of lithium chloride (LiCl) would influence the propagation of the brain excitability-related phenomenon known as cortical spreading depression (CSD). Male well-nourished (W; fed a lab chow diet with 22% protein; n=22) and previously protein-malnourished rats (M; fed a low-quality 8% protein diet; proteins mostly from vegetable source; n=20) were treated at 75-80 days of age with a single intraperitoneal injection of either 50 mg/kg LiCl (n=9 W and 10 M rats) or saline (n=13 W and 10 M rats). When the pups were 90-110 days, CSD was elicited at the frontal cortex and recorded during 4 hours at two cortical parietal points. In malnourished, but not in well-nourished rats, lithium treatment lowered CSD velocities (P malnutrition on the CSD-impairing action of a single lithium administration, suggesting a lithium/nutrition interaction.

  1. Changes in magnetization transfer MRI correlate with spreading depression-induced astroglial reactivity and increased protein expression in mice.

    Science.gov (United States)

    Lascola, Christopher D; Song, Allen W; Haystead, Timothy A; Warner, David S; Verleysen, Katleen; Freed, Tiffany A; Provenzale, James M

    2004-12-01

    Gliosis refers to a range of glial cell transformations that vary according to specific brain pathologic states. Disease, however, is not a prerequisite for gliosis because glial reactivity may also be seen in regions of increased physiologic activity. Our study tests the hypothesis that high-field-strength magnetization transfer MRI is a sensitive technique for detecting transient glial reactivity after experimental spreading depression, a relatively benign perturbation unaccompanied by cell injury. Unilateral neocortical spreading depression was elicited in mouse cerebral hemispheres and confirmed by transcranial blood flow and extracellular potential measurements. After 3 days, mice were imaged at 4 T using magnetization transfer techniques. Astroglial reactivity was determined immunohistochemically, and protein expression in control and experimental hemispheres was compared using proteomic techniques. Sixteen ([mean +/- SD] +/- 3) spreading depressions (n = 10) were recorded in experimental hemispheres. Spreading depression was never observed in control hemispheres. At 3 days, an 8% decrease (p < 0.05, n = 4) in magnetization transfer signal intensity was measured in experimental hemispheres, which was associated with a 37% increase (p < 0.001, n = 4) in the intensity of glial fibrillary acidic protein staining. Proteomic analysis performed 3 days after the induction of spreading depression showed upregulation of at least 56 proteins, including extracellular and intracellular elements. Magnetization transfer at 4.0-T MRI is a sensitive method for detecting glial reactivity and changes in protein expression not associated with cell injury. These results suggest magnetization transfer MRI techniques may have potential for detecting glial reactivity in physiologic processes such as learning and in early disease states.

  2. Oxygen and glucose deprivation (OGD)-induced spreading depression in the Substantia Nigra.

    Science.gov (United States)

    Karunasinghe, Rashika N; Lipski, Janusz

    2013-08-21

    Spreading depression (SD) is a profound depolarization of neurons and glia that propagates in a wave-like manner across susceptible brain regions, and can develop during periods of compromised cellular energy such as ischemia, when it influences the severity of acute neuronal damage. Although SD has been well characterized in the cerebral cortex and hippocampus, little is known of this event in the Substantia Nigra (SN), a brainstem nucleus engaged in motor control and reward-related behavior. Transverse brain slices (250 μm; P21-23 rats) containing the SN were subject to oxygen and glucose deprivation (OGD) tests, modeling brain ischemia. SD developed in lateral aspects of the SN within 3.3±0.2 min of OGD onset, and spread through the Substantia Nigra pars reticulata (SNr), as indicated by fast-occurring and propagating increased tissue light transmittance and negative shift of extracellular DC potential. These events were associated with profound mitochondrial membrane depolarization (ΔΨm) throughout the SN, as demonstrated by increased Rhodamine 123 fluorescence. Extracellular recordings from individual SNr neurons indicated rapid depolarization followed by depolarizing block, while dopaminergic neurons in the Substantia Nigra pars compacta (SNc) showed inhibition of firing associated with hyperpolarization. SD evoked in the SNr was similar to OGD-induced SD in the CA1 region in hippocampal slices. In the hippocampus, SD also developed during anoxia or aglycemia alone (associated with less profound ΔΨm than OGD), while these conditions rarely led to SD in the SNr. Our results demonstrate that OGD consistently evokes SD in the SN, and that this phenomenon only involves the SNr. It remains to be established whether nigral SD contributes to neuronal damage associated with a sudden-onset form of Parkinson's disease known as 'vascular parkinsonism'.

  3. Cell swelling increases the severity of spreading depression in Locusta migratoria.

    Science.gov (United States)

    Spong, Kristin E; Chin, Brittany; Witiuk, Kelsey L M; Robertson, R Meldrum

    2015-12-01

    Progressive accumulation of extracellular potassium ions can trigger propagating waves of spreading depression (SD), which are associated with dramatic increases in extracellular potassium levels ([K(+)]o) and arrest in neural activity. In the central nervous system the restricted nature of the extracellular compartment creates an environment that is vulnerable to disturbances in ionic homeostasis. Here we investigate how changes in the size of the extracellular space induced by alterations in extracellular osmolarity affect locust SD. We found that hypotonic exposure increased susceptibility to experimentally induced SD evidenced by a decrease in the latency to onset and period between individual events. Hypertonic exposure was observed to delay the onset of SD or prevent the occurrence altogether. Additionally, the magnitude of extracellular K(+) concentration ([K(+)]o) disturbance during individual SD events was significantly greater and they were observed to propagate more quickly under hypotonic conditions compared with hypertonic conditions. Our results are consistent with a conclusion that hypotonic exposure reduced the size of the extracellular compartment by causing cell swelling and thus facilitated the accumulation of K(+) ions. Lastly, we found that pharmacologically reducing the accumulation of extracellular K(+) using the K(+) channel blocker tetraethylammonium slowed the rate of SD propagation while increasing [K(+)]o through inhibition of the Na-K-2Cl cotransporter increased propagation rates. Overall our findings indicate that treatments or conditions that act to reduce the accumulation of extracellular K(+) help to protect against the development of SD and attenuate the spread of ionic disturbance adding to the evidence that diffusion of K(+) is a leading event during locust SD.

  4. Disruption of the blood-brain barrier exacerbates spreading depression in the locust CNS.

    Science.gov (United States)

    Spong, Kristin E; Rochon-Terry, Geneviève; Money, Tomas G A; Robertson, R Meldrum

    2014-07-01

    In response to cellular stress in the nervous system of the locust (Locusta migratoria) neural function is interrupted in association with ionic disturbances propagating throughout nervous tissue (Spreading depression; SD). The insect blood-brain barrier (BBB) plays a critical role in the regulation of ion levels within the CNS. We investigated how a disruption in barrier function by transient exposure to 3M urea affects locusts' vulnerability to disturbances in ion levels. Repetitive SD was induced by bath application of ouabain and the extracellular potassium concentration ([K(+)]o) within the metathoracic ganglion (MTG) was monitored. Urea treatment increased the susceptibility to ouabain and caused a progressive impairment in the ability to maintain baseline [K(+)]o levels during episodes of repetitive SD. Additionally, using a within animal protocol we demonstrate that waves of SD, induced by high K(+), propagate throughout the MTG faster following disruption of the BBB. Lastly, we show that targeting the BBB of intact animals reduces their ability to sustain neural function during anoxic conditions. Our findings indicate that locust's ability to withstand stress is diminished following a reduction in barrier function likely due to an impairment of the ability of neural tissue to maintain ionic gradients.

  5. In Vivo Voltage-Sensitive Dye Study of Lateral Spreading of Cortical Activity in Mouse Primary Visual Cortex Induced by a Current Impulse.

    Directory of Open Access Journals (Sweden)

    Tamás Dávid Fehérvári

    Full Text Available In the mammalian primary visual cortex (V1, lateral spreading of excitatory potentials is believed to be involved in spatial integrative functions, but the underlying cortical mechanism is not well understood. Visually-evoked population-level responses have been shown to propagate beyond the V1 initial activation site in mouse, similar to higher mammals. Visually-evoked responses are, however, affected by neuronal circuits prior to V1 (retina, LGN, making the separate analysis of V1 difficult. Intracortical stimulation eliminates these initial processing steps. We used in vivo RH1691 voltage-sensitive dye (VSD imaging and intracortical microstimulation in adult C57BL/6 mice to elucidate the spatiotemporal properties of population-level signal spreading in V1 cortical circuits. The evoked response was qualitatively similar to that measured in single-cell electrophysiological experiments in rodents: a fast transient fluorescence peak followed by a fast and a slow decrease or hyperpolarization, similar to EPSP and fast and slow IPSPs in single cells. The early cortical response expanded at speeds commensurate with long horizontal projections (at 5% of the peak maximum, 0.08-0.15 m/s however, the bulk of the VSD signal propagated slowly (at half-peak maximum, 0.05-0.08 m/s suggesting an important role of regenerative multisynaptic transmission through short horizontal connections in V1 spatial integrative functions. We also found a tendency for a widespread and fast cortical response suppression in V1, which was eliminated by GABAA-antagonists gabazine and bicuculline methiodide. Our results help understand the neuronal circuitry involved in lateral spreading in V1.

  6. Multi-dimensional modulations of α and γ cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder.

    Science.gov (United States)

    Schoenberg, Poppy L A; Speckens, Anne E M

    2015-02-01

    To illuminate candidate neural working mechanisms of Mindfulness-Based Cognitive Therapy (MBCT) in the treatment of recurrent depressive disorder, parallel to the potential interplays between modulations in electro-cortical dynamics and depressive symptom severity and self-compassionate experience. Linear and nonlinear α and γ EEG oscillatory dynamics were examined concomitant to an affective Go/NoGo paradigm, pre-to-post MBCT or natural wait-list, in 51 recurrent depressive patients. Specific EEG variables investigated were; (1) induced event-related (de-) synchronisation (ERD/ERS), (2) evoked power, and (3) inter-/intra-hemispheric coherence. Secondary clinical measures included depressive severity and experiences of self-compassion. MBCT significantly downregulated α and γ power, reflecting increased cortical excitability. Enhanced α-desynchronisation/ERD was observed for negative material opposed to attenuated α-ERD towards positively valenced stimuli, suggesting activation of neural networks usually hypoactive in depression, related to positive emotion regulation. MBCT-related increase in left-intra-hemispheric α-coherence of the fronto-parietal circuit aligned with these synchronisation dynamics. Ameliorated depressive severity and increased self-compassionate experience pre-to-post MBCT correlated with α-ERD change. The multi-dimensional neural mechanisms of MBCT pertain to task-specific linear and non-linear neural synchronisation and connectivity network dynamics. We propose MBCT-related modulations in differing cortical oscillatory bands have discrete excitatory (enacting positive emotionality) and inhibitory (disengaging from negative material) effects, where mediation in the α and γ bands relates to the former.

  7. Nitric oxide scavenging by hemoglobin or nitric oxide synthase inhibition by N-Nitro-L-arginine induces cortical spreading ischemia when K+0+ is increased in the subarachnoid space

    DEFF Research Database (Denmark)

    Dreier, J.P.; Körner, K.; Ebert, Nathalie

    1998-01-01

    Cerebral blood flow, nitric oxide, potassium, spreading depression, vasospasm, migraine, migrainous stroke, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS)......Cerebral blood flow, nitric oxide, potassium, spreading depression, vasospasm, migraine, migrainous stroke, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS)...

  8. Brimonidine tartrate effect on retinal spreading depression depends on Müller cells

    Directory of Open Access Journals (Sweden)

    Vinícius Vanzan Pimentel de Oliveira

    2014-12-01

    Full Text Available Objective: Demonstrate the Brimonidine effect over Retinal Spreading Depression (SD. Brimonidine is an alpha-2–adrenergic receptor agonist, used in the management of glaucoma. Alpha2-agonists have been shown to be neuroprotective in various experimental models, however the molecular and cellular targets leading to these actions are still poorly defined. The SD of neuronal electric activity is a wave of cellular massive sustained depolarization that damages the nervous tissue. Local trauma, pressure, ischemic injuries and other chemical agents as high extracellular potassium concentration or glutamate, can trigger SD, leading to exaggerated focal electrical followed by an electrical silence. Methods: Using chicken retina as model, we performed alpha2-receptor detection by Western Blotting and Immunohistochemistry. After that we obtained electrical signals of SD by microelectrodes on retina in the absence or presence of Brimonidine. For in vivo visualization we observed retina with optical coherence tomography on normal state, with SD passing, and with SD + Brimonidine. Results: Our data demonstrated that: (1 alpha2-adrenergic receptors are present in Müller cells, (2 the treatment with Brimonidine decreases the SD‘s velocity as well as the voltage of SD waves and (3 OCT revealed that SD creates a hyper reflectance at inner plexiform layer, but on retinal treatment with brimonidine, SD was not visualized. Conclusions: Our study about brimonidine possible pathways of neuroprotection we observed it reduces SD (a neuronal damage wave, identified a new cellular target – the Müller cells, as well as, firstly demonstrated SD on OCT, showing that the inner plexiform layer is the main optically affected layer on SD.

  9. 'Spreading depression of Leão' and its emerging relevance to acute brain injury in humans

    DEFF Research Database (Denmark)

    Lauritzen, Martin; Strong, Anthony J

    2017-01-01

    experiencing the visual (or sensorimotor) aura of migraine. In this review, we trace from their first description in rabbits through to their detection and study in migraine and the injured human brain, and from our personal perspectives, the evolution of understanding of the importance of spread of mass...... to clearer concepts of how ischaemic and traumatic lesions evolve in the injured human brain, and of how to seek to improve clinical management and outcome. Recognition of the likely fundamental significance of spreading depolarisations for this wide range of serious acute encephalopathies in humans provides......A new research field in translational neuroscience has opened as a result of the recognition since 2002 that "spreading depression of Leão" can be detected in many patients with acute brain injury, whether vascular and spontaneous, or traumatic in origin, as well as in those many individuals...

  10. Cortical abnormalities in adults and adolescents with major depression based on brain scans from 20 cohorts worldwide in the ENIGMA Major Depressive Disorder Working Group

    Science.gov (United States)

    Schmaal, L; Hibar, D P; Sämann, P G; Hall, G B; Baune, B T; Jahanshad, N; Cheung, J W; van Erp, T G M; Bos, D; Ikram, M A; Vernooij, M W; Niessen, W J; Tiemeier, H; Hofman, A; Wittfeld, K; Grabe, H J; Janowitz, D; Bülow, R; Selonke, M; Völzke, H; Grotegerd, D; Dannlowski, U; Arolt, V; Opel, N; Heindel, W; Kugel, H; Hoehn, D; Czisch, M; Couvy-Duchesne, B; Rentería, M E; Strike, L T; Wright, M J; Mills, N T; de Zubicaray, G I; McMahon, K L; Medland, S E; Martin, N G; Gillespie, N A; Goya-Maldonado, R; Gruber, O; Krämer, B; Hatton, S N; Lagopoulos, J; Hickie, I B; Frodl, T; Carballedo, A; Frey, E M; van Velzen, L S; Penninx, B W J H; van Tol, M-J; van der Wee, N J; Davey, C G; Harrison, B J; Mwangi, B; Cao, B; Soares, J C; Veer, I M; Walter, H; Schoepf, D; Zurowski, B; Konrad, C; Schramm, E; Normann, C; Schnell, K; Sacchet, M D; Gotlib, I H; MacQueen, G M; Godlewska, B R; Nickson, T; McIntosh, A M; Papmeyer, M; Whalley, H C; Hall, J; Sussmann, J E; Li, M; Walter, M; Aftanas, L; Brack, I; Bokhan, N A; Thompson, P M; Veltman, D J

    2017-01-01

    The neuro-anatomical substrates of major depressive disorder (MDD) are still not well understood, despite many neuroimaging studies over the past few decades. Here we present the largest ever worldwide study by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) Major Depressive Disorder Working Group on cortical structural alterations in MDD. Structural T1-weighted brain magnetic resonance imaging (MRI) scans from 2148 MDD patients and 7957 healthy controls were analysed with harmonized protocols at 20 sites around the world. To detect consistent effects of MDD and its modulators on cortical thickness and surface area estimates derived from MRI, statistical effects from sites were meta-analysed separately for adults and adolescents. Adults with MDD had thinner cortical gray matter than controls in the orbitofrontal cortex (OFC), anterior and posterior cingulate, insula and temporal lobes (Cohen's d effect sizes: −0.10 to −0.14). These effects were most pronounced in first episode and adult-onset patients (>21 years). Compared to matched controls, adolescents with MDD had lower total surface area (but no differences in cortical thickness) and regional reductions in frontal regions (medial OFC and superior frontal gyrus) and primary and higher-order visual, somatosensory and motor areas (d: −0.26 to −0.57). The strongest effects were found in recurrent adolescent patients. This highly powered global effort to identify consistent brain abnormalities showed widespread cortical alterations in MDD patients as compared to controls and suggests that MDD may impact brain structure in a highly dynamic way, with different patterns of alterations at different stages of life. PMID:27137745

  11. Cortical abnormalities in adults and adolescents with major depression based on brain scans from 20 cohorts worldwide in the ENIGMA Major Depressive Disorder Working Group.

    Science.gov (United States)

    Schmaal, L; Hibar, D P; Sämann, P G; Hall, G B; Baune, B T; Jahanshad, N; Cheung, J W; van Erp, T G M; Bos, D; Ikram, M A; Vernooij, M W; Niessen, W J; Tiemeier, H; Hofman, A; Wittfeld, K; Grabe, H J; Janowitz, D; Bülow, R; Selonke, M; Völzke, H; Grotegerd, D; Dannlowski, U; Arolt, V; Opel, N; Heindel, W; Kugel, H; Hoehn, D; Czisch, M; Couvy-Duchesne, B; Rentería, M E; Strike, L T; Wright, M J; Mills, N T; de Zubicaray, G I; McMahon, K L; Medland, S E; Martin, N G; Gillespie, N A; Goya-Maldonado, R; Gruber, O; Krämer, B; Hatton, S N; Lagopoulos, J; Hickie, I B; Frodl, T; Carballedo, A; Frey, E M; van Velzen, L S; Penninx, B W J H; van Tol, M-J; van der Wee, N J; Davey, C G; Harrison, B J; Mwangi, B; Cao, B; Soares, J C; Veer, I M; Walter, H; Schoepf, D; Zurowski, B; Konrad, C; Schramm, E; Normann, C; Schnell, K; Sacchet, M D; Gotlib, I H; MacQueen, G M; Godlewska, B R; Nickson, T; McIntosh, A M; Papmeyer, M; Whalley, H C; Hall, J; Sussmann, J E; Li, M; Walter, M; Aftanas, L; Brack, I; Bokhan, N A; Thompson, P M; Veltman, D J

    2016-05-03

    The neuro-anatomical substrates of major depressive disorder (MDD) are still not well understood, despite many neuroimaging studies over the past few decades. Here we present the largest ever worldwide study by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) Major Depressive Disorder Working Group on cortical structural alterations in MDD. Structural T1-weighted brain magnetic resonance imaging (MRI) scans from 2148 MDD patients and 7957 healthy controls were analysed with harmonized protocols at 20 sites around the world. To detect consistent effects of MDD and its modulators on cortical thickness and surface area estimates derived from MRI, statistical effects from sites were meta-analysed separately for adults and adolescents. Adults with MDD had thinner cortical gray matter than controls in the orbitofrontal cortex (OFC), anterior and posterior cingulate, insula and temporal lobes (Cohen's d effect sizes: -0.10 to -0.14). These effects were most pronounced in first episode and adult-onset patients (>21 years). Compared to matched controls, adolescents with MDD had lower total surface area (but no differences in cortical thickness) and regional reductions in frontal regions (medial OFC and superior frontal gyrus) and primary and higher-order visual, somatosensory and motor areas (d: -0.26 to -0.57). The strongest effects were found in recurrent adolescent patients. This highly powered global effort to identify consistent brain abnormalities showed widespread cortical alterations in MDD patients as compared to controls and suggests that MDD may impact brain structure in a highly dynamic way, with different patterns of alterations at different stages of life.Molecular Psychiatry advance online publication, 3 May 2016; doi:10.1038/mp.2016.60.

  12. Spreading Depolarizations Have Prolonged Direct Current Shifts and Are Associated with Poor Outcome in Brain Trauma

    Science.gov (United States)

    2011-01-01

    prognosis . Keywords: cortical spreading depression; electroencephalography; craniotomy; signal processing; acute brain injury Introduction Cortical...GCS =Glasgow coma scale. differed from normality and Kruskai-Wallis tests were used for non-parametric analysis of variance. Data are reported as...graded prognosis corresponding to 100% (isoelectric depolarizations), 60% (depolarizations with de- pression periods) and 23% (no depolarizations) of

  13. Mild cognitive impairment, poor episodic memory, and late-life depression are associated with cerebral cortical thinning and increased white matter hyperintensities

    Directory of Open Access Journals (Sweden)

    Motonobu eFujishima

    2014-11-01

    Full Text Available In various independent studies to date, cerebral cortical thickness and white matter hyperintensity (WMH volume have been associated with episodic memory, depression, and mild cognitive impairment (MCI. The aim of this study was to uncover variations in cortical thickness and WMH volume in association with episodic memory, depressive state, and the presence of MCI simultaneously in a single study population. The participants were 186 individuals with MCI (clinical dementia rating [CDR] of 0.5 and 136 healthy elderly controls (HCs; CDR of 0 drawn from two community-based cohort studies in northern Japan. We computed cerebral cortical thickness and WMH volume by using MR scans and statistically analyzed differences in these indices between HCs and MCI participants. We also assessed the associations of these indices with memory performance and depressive state in participants with MCI. Compared with HCs, MCI participants exhibited thinner cortices in the temporal and inferior parietal lobes and greater WMH volumes in the corona radiata and semioval center. In MCI participants, poor episodic memory was associated with thinner cortices in the left entorhinal region and increased WMH volume in the posterior periventricular regions. Compared with non-depressed MCI participants, depressed MCI participants showed reduced cortical thickness in the anterior medial temporal lobe and ambient gyrus adjacent to the amygdala bilaterally, as well as greater WMH volume as a percentage of the total intracranial volume (WMHr. A higher WMHr was associated with cortical thinning in the frontal, temporal, and parietal regions in MCI participants. These results demonstrate that episodic memory and depression are associated with both cortical thickness and WMH volume in MCI participants. Additional longitudinal studies are needed to clarify the dynamic associations and interactions among these indices.

  14. A Preliminary Study of the Influence of Age of Onset and Childhood Trauma on Cortical Thickness in Major Depressive Disorder

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    Natalia Jaworska

    2014-01-01

    Full Text Available Background. Major depressive disorder (MDD neural underpinnings may differ based on onset age and childhood trauma. We assessed cortical thickness in patients who differed in age of MDD onset and examined trauma history influence. Methods. Adults with MDD (N=36 and controls (HC; N=18 underwent magnetic resonance imaging. Twenty patients had MDD onset 25 years of age (adult onset. The MDD group was also subdivided into those with (N=12 and without (N=19 physical and/or sexual abuse as assessed by the Childhood Trauma Questionnaire (CTQ. Cortical thickness was analyzed with FreeSurfer software. Results. Thicker frontal pole and a tendency for thinner transverse temporal cortices existed in MDD. The former was driven by the pediatric onset group and abuse history (independently, particularly in the right frontal pole. Inverse correlations existed between CTQ scores and frontal pole cortex thickness. A similar inverse relation existed with left inferior and right superior parietal cortex thickness. The superior temporal cortex tended to be thinner in pediatric versus adult onset groups with childhood abuse. Conclusions. This preliminary work suggests neural differences between pediatric and adult MDD onset. Trauma history also contributes to cytoarchitectural modulation. Thickened frontal pole cortices as a compensatory mechanism in MDD warrant evaluation.

  15. Reduced density of glutamine synthetase immunoreactive astrocytes in different cortical areas in major depression but not in bipolar I disorder.

    Science.gov (United States)

    Bernstein, Hans-Gert; Meyer-Lotz, Gabriela; Dobrowolny, Henrik; Bannier, Jana; Steiner, Johann; Walter, Martin; Bogerts, Bernhard

    2015-01-01

    There is increasing evidence for disturbances within the glutamate system in patients with affective disorders, which involve disruptions of the glutamate-glutamine-cycle. The mainly astroglia-located enzyme glutamine synthetase (GS) catalyzes the ATP-dependent condensation of ammonia and glutamate to form glutamine, thus playing a central role in glutamate and glutamine homoeostasis. However, GS is also expressed in numerous oligodendrocytes (OLs), another class of glial cells implicated in mood disorder pathology. To learn more about the role of glia-associated GS in mental illnesses, we decided to find out if numerical densities of glial cells immunostained for the enzyme protein differ between subjects with major depressive disorder, bipolar disorder (BD), and psychically healthy control cases. Counting of GS expressing astrocytes (ACs) and OLs in eight cortical and two subcortical brain regions of subjects with mood disorder (N = 14), BD (N = 15), and controls (N = 16) revealed that in major depression the densities of ACs were significantly reduced in some cortical but not subcortical gray matter areas, whereas no changes were found for OLs. In BD no alterations of GS-immunoreactive glia were found. From our findings we conclude that (1) GS expressing ACs are prominently involved in glutamate-related disturbances in major depression, but not in BD and (2) GS expressing OLs, though being present in significant numbers in prefrontal cortical areas, play a minor (if any) role in mood disorder pathology. The latter assumption is supported by findings of others showing that - at least in the mouse brain cortex - GS immunoreactive oligodendroglial cells are unable to contribute to the glutamate-glutamine-cycle due to the complete lack of amino acid transporters (Takasaki et al., 2010).

  16. Unilateral Left-Hand Contractions Produce Widespread Depression of Cortical Activity after Their Execution.

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    Fernando Cross-Villasana

    Full Text Available The execution of unilateral hand contractions before performance has been reported to produce behavioral aftereffects in various tasks. These effects have been regularly attributed to an induced shift in activation asymmetry to the contralateral hemisphere produced by the contractions. An alternative explanation proposes a generalized state of reduced bilateral cortical activity following unilateral hand contractions. The current experiment contrasted the above explanation models and tested the state of cortical activity after the termination of unilateral hand contractions. Twenty right-handed participants performed hand contractions in two blocks, one for each hand. Using electroencephalogram (EEG, the broad alpha band and its asymmetry between hemispheres before, during, and after hand contractions were analyzed. During contractions, significant bilateral decrease in alpha amplitudes (indicating cortical activation emerged for both hands around sensory-motor regions. After contractions, alpha amplitudes increased significantly over the whole scalp when compared to baseline, but only for the left hand. No modulation of hemispheric asymmetry was observed at any phase. The results suggest that unilateral hand contractions produce a state of reduced cortical activity after their termination, which is more pronounced if the left hand was used. Consequently, we propose that the reduced cortical activity (and not the persistent activation asymmetry may facilitate engagement in subsequent behavior, probably due to preventing interference from other, nonessential cortical regions.

  17. Unilateral Left-Hand Contractions Produce Widespread Depression of Cortical Activity after Their Execution.

    Science.gov (United States)

    Cross-Villasana, Fernando; Gröpel, Peter; Doppelmayr, Michael; Beckmann, Jürgen

    2015-01-01

    The execution of unilateral hand contractions before performance has been reported to produce behavioral aftereffects in various tasks. These effects have been regularly attributed to an induced shift in activation asymmetry to the contralateral hemisphere produced by the contractions. An alternative explanation proposes a generalized state of reduced bilateral cortical activity following unilateral hand contractions. The current experiment contrasted the above explanation models and tested the state of cortical activity after the termination of unilateral hand contractions. Twenty right-handed participants performed hand contractions in two blocks, one for each hand. Using electroencephalogram (EEG), the broad alpha band and its asymmetry between hemispheres before, during, and after hand contractions were analyzed. During contractions, significant bilateral decrease in alpha amplitudes (indicating cortical activation) emerged for both hands around sensory-motor regions. After contractions, alpha amplitudes increased significantly over the whole scalp when compared to baseline, but only for the left hand. No modulation of hemispheric asymmetry was observed at any phase. The results suggest that unilateral hand contractions produce a state of reduced cortical activity after their termination, which is more pronounced if the left hand was used. Consequently, we propose that the reduced cortical activity (and not the persistent activation asymmetry) may facilitate engagement in subsequent behavior, probably due to preventing interference from other, nonessential cortical regions.

  18. Aristides Leão: a birth centennial homage with comments on his spreading depression

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    2015-06-01

    Full Text Available The year of 2014 is the birth centenary of Aristides Azevedo Pacheco Leão (1914-1993, and also marks seventy years of the publication of his discovery of the novel electrophysiological phenomenon, named by him “spreading depression” (SD, soon designated “Leão’s wave” or “Leão’s spreading depression”. This was a remarkable scientific milestone, and the author must be celebrated for this achievement, as the studies he triggered proceeded worldwide, with new concepts, as spreading depolarization, until the present days. Robust experimental and clinical evidence emerged to suggest that these and related electrophysiological phenomena are involved in the mechanisms of migraine aura, acute cerebrovascular diseases, traumatic brain injury, transient global amnesia, epileptic seizures, and their pathophysiological characteristics come to offer new therapeutic perspectives. He was a remarkable and complex personality, and the authors remit the readers to a paper where his personal life is contemplated.

  19. The error processing system in major depressive disorder: cortical phenotypal marker hypothesis

    NARCIS (Netherlands)

    Schoenberg, P.L.

    2014-01-01

    Major depressive disorder (MDD) ensues reduced goal-directed cognition and behaviour. Cognitive and emotional flexibility to disengage and adapt future responses was examined in the error processing system (error-related negativity/ERN, error-positivity/Pe event-related potentials) of 58 depressed p

  20. Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

    DEFF Research Database (Denmark)

    Järnum, Hanna; Eskildsen, Simon Fristed; Steffensen, Elena G

    2011-01-01

    disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan. Method:  A longitudinal 3.0-Tesla (T) magnetic resonance imaging...

  1. Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

    DEFF Research Database (Denmark)

    Järnum, Hanna; Eskildsen, Simon Fristed; Steffensen, Elena G;

    2011-01-01

    disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan. Method:  A longitudinal 3.0-Tesla (T) magnetic resonance imaging...

  2. Relationship between neurotoxic kynurenine metabolites and reductions in right medial prefrontal cortical thickness in major depressive disorder.

    Science.gov (United States)

    Meier, Timothy B; Drevets, Wayne C; Wurfel, Brent E; Ford, Bart N; Morris, Harvey M; Victor, Teresa A; Bodurka, Jerzy; Teague, T Kent; Dantzer, Robert; Savitz, Jonathan

    2016-03-01

    Reductions in gray matter volume of the medial prefrontal cortex (mPFC), especially the rostral and subgenual anterior cingulate cortex (rACC, sgACC) are a widely reported finding in major depressive disorder (MDD). Inflammatory mediators, which are elevated in a subgroup of patients with MDD, activate the kynurenine metabolic pathway and increase production of neuroactive metabolites such as kynurenic acid (KynA), 3-hydroxykynurenine (3HK) and quinolinic acid (QA) which influence neuroplasticity. It is not known whether the alterations in brain structure and function observed in major depressive disorders are due to the direct effect of inflammatory mediators or the effects of neurotoxic kynurenine metabolites. Here, using partial posterior predictive distribution mediation analysis, we tested whether the serum concentrations of kynurenine pathway metabolites mediated reductions in cortical thickness in mPFC regions in MDD. Further, we tested whether any association between C-reactive protein (CRP) and cortical thickness would be mediated by kynurenine pathway metabolites. Seventy-three unmedicated subjects who met DSM-IV-TR criteria for MDD and 91 healthy controls (HC) completed MRI scanning using a pulse sequence optimized for tissue contrast resolution. Automated cortical parcellation was performed using the PALS-B12 Brodmann area atlas as implemented in FreeSurfer in order to compare the cortical thickness and cortical area of six PFC regions: Brodmann areas (BA) 9, 10, 11, 24, 25, and 32. Serum concentrations of kynurenine pathway metabolites were determined by high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS) detection, while high-sensitivity CRP concentration was measured immunoturbidimetrically. Compared with HCs, the MDD group showed a reduction in cortical thickness of the right BA24 (pdepressive episodes displayed thinner cortex in BA32 (p<0.05). Consistent with our previous findings in an overlapping sample, the KynA/3

  3. Early cortical biomarkers of longitudinal transcutaneous vagus nerve stimulation treatment success in depression

    OpenAIRE

    Fang, Jiliang; Egorova, Natalia; Rong, Peijing; Liu, Jun; Hong, Yang; Fan, Yangyang; Wang, Xiaoling; Wang, Honghong; Yu, Yutian; Ma, Yunyao; Xu, Chunhua; Li, Shaoyuan; Zhao, Jingjun; Luo, Man; Bing ZHU

    2016-01-01

    Transcutaneous vagus nerve stimulation (tVNS), a non-invasive method of brain stimulation through the auricular branch of the vagus nerve, has shown promising results in treating major depressive disorder (MDD) in several pilot studies. However, the neural mechanism by which the effect on depression might be achieved has not been fully investigated, with only a few neuroimaging studies demonstrating tVNS-induced changes in the brains of healthy volunteers. Identifying specific neural pathways...

  4. Prefrontal cortical circuit for depression- and anxiety-related behaviors mediated by cholecystokinin: role of ΔFosB.

    Science.gov (United States)

    Vialou, Vincent; Bagot, Rosemary C; Cahill, Michael E; Ferguson, Deveroux; Robison, Alfred J; Dietz, David M; Fallon, Barbara; Mazei-Robison, Michelle; Ku, Stacy M; Harrigan, Eileen; Winstanley, Catherine A; Joshi, Tej; Feng, Jian; Berton, Olivier; Nestler, Eric J

    2014-03-12

    Decreased medial prefrontal cortex (mPFC) neuronal activity is associated with social defeat-induced depression- and anxiety-like behaviors in mice. However, the molecular mechanisms underlying the decreased mPFC activity and its prodepressant role remain unknown. We show here that induction of the transcription factor ΔFosB in mPFC, specifically in the prelimbic (PrL) area, mediates susceptibility to stress. ΔFosB induction in PrL occurred selectively in susceptible mice after chronic social defeat stress, and overexpression of ΔFosB in this region, but not in the nearby infralimbic (IL) area, enhanced stress susceptibility. ΔFosB produced these effects partly through induction of the cholecystokinin (CCK)-B receptor: CCKB blockade in mPFC induces a resilient phenotype, whereas CCK administration into mPFC mimics the anxiogenic- and depressant-like effects of social stress. We previously found that optogenetic stimulation of mPFC neurons in susceptible mice reverses several behavioral abnormalities seen after chronic social defeat stress. Therefore, we hypothesized that optogenetic stimulation of cortical projections would rescue the pathological effects of CCK in mPFC. After CCK infusion in mPFC, we optogenetically stimulated mPFC projections to basolateral amygdala or nucleus accumbens, two subcortical structures involved in mood regulation. Stimulation of corticoamygdala projections blocked the anxiogenic effect of CCK, although no effect was observed on other symptoms of social defeat. Conversely, stimulation of corticoaccumbens projections reversed CCK-induced social avoidance and sucrose preference deficits but not anxiogenic-like effects. Together, these results indicate that social stress-induced behavioral deficits are mediated partly by molecular adaptations in mPFC involving ΔFosB and CCK through cortical projections to distinct subcortical targets.

  5. The 'resting-state hypothesis' of major depressive disorder-a translational subcortical-cortical framework for a system disorder.

    Science.gov (United States)

    Northoff, Georg; Wiebking, Christine; Feinberg, Todd; Panksepp, Jaak

    2011-10-01

    Major depressive disorder (MDD) has traditionally been characterized by various psychological symptoms, involvement of diverse functional systems (e.g., somatic, affect, cognition, reward, etc.), and with progress in neuroscience, an increasing number of brain regions. This has led to the general assumption that MDD is a stress-responsive brain 'system disorder' where either one or several alterations infiltrate a large number of functional systems in the brain that control the organism's somatic, affective, and cognitive life. However, while the effects or consequences of the abnormal changes in the functional systems of, for instance affect, cognition or reward have been investigated extensively, the underlying core mechanism(s) underlying MDD remain unknown. Hypotheses are proliferating rapidly, though. Based on recent findings, we will entertain an abnormality in the resting-state activity in MDD to be a core feature. Based on both animal and human data, we hypothesize that abnormal resting-state activity levels may impact stimulus-induced neural activity in medially situated core systems for self-representation as well as external stimulus (especially stress, specifically separation distress) interactions. Moreover, due to nested hierarchy between subcortical and cortical regions, we assume 'highjacking' of higher cortical affective and cognitive functions by lower subcortical primary-process emotional systems. This may account for the predominance of negative affect in somatic and cognitive functional system operations with the consecutive generation of the diverse symptoms in MDD. We will here focus on the neuroanatomical and biochemical basis of resting-state abnormalities in MDD including their linkage to the diverse psychopathological symptoms in depression. However, our 'resting-state hypothesis' may go well beyond that by being sufficiently precise to be linked to genetic, social, immunological, and endocrine dimensions and hypotheses as well as to

  6. Local cortical thinning links to resting-state disconnectivity in major depressive disorder

    NARCIS (Netherlands)

    van Tol, M. -J.; Li, M.; Metzger, C. D.; Hailla, N.; Horn, D. I.; Li, W.; Heinze, H. J.; Bogerts, B.; Steiner, J.; He, H.; Walter, M.

    2014-01-01

    Background. Local structural and metabolic as well as inter-regional connectivity abnormalities have been implicated in the neuropathology of major depressive disorder (MDD). How local tissue properties affect intrinsic functional connectivity is, however, unclear. Using a cross-sectional, multi-mod

  7. Birth Weight and Adult IQ, but Not Anxious-Depressive Psychopathology, Are Associated with Cortical Surface Area: A Study in Twins.

    Directory of Open Access Journals (Sweden)

    Aldo Córdova-Palomera

    Full Text Available Previous research suggests that low birth weight (BW induces reduced brain cortical surface area (SA which would persist until at least early adulthood. Moreover, low BW has been linked to psychiatric disorders such as depression and psychological distress, and to altered neurocognitive profiles.We present novel findings obtained by analysing high-resolution structural MRI scans of 48 twins; specifically, we aimed: i to test the BW-SA association in a middle-aged adult sample; and ii to assess whether either depression/anxiety disorders or intellectual quotient (IQ influence the BW-SA link, using a monozygotic (MZ twin design to separate environmental and genetic effects.Both lower BW and decreased IQ were associated with smaller total and regional cortical SA in adulthood. Within a twin pair, lower BW was related to smaller total cortical and regional SA. In contrast, MZ twin differences in SA were not related to differences in either IQ or depression/anxiety disorders.The present study supports findings indicating that i BW has a long-lasting effect on cortical SA, where some familial and environmental influences alter both foetal growth and brain morphology; ii uniquely environmental factors affecting BW also alter SA; iii higher IQ correlates with larger SA; and iv these effects are not modified by internalizing psychopathology.

  8. Birth Weight and Adult IQ, but Not Anxious-Depressive Psychopathology, Are Associated with Cortical Surface Area: A Study in Twins

    Science.gov (United States)

    Córdova-Palomera, Aldo; Fatjó-Vilas, Mar; Falcón, Carles; Bargalló, Nuria; Alemany, Silvia; Crespo-Facorro, Benedicto; Nenadic, Igor; Fañanás, Lourdes

    2015-01-01

    Background Previous research suggests that low birth weight (BW) induces reduced brain cortical surface area (SA) which would persist until at least early adulthood. Moreover, low BW has been linked to psychiatric disorders such as depression and psychological distress, and to altered neurocognitive profiles. Aims We present novel findings obtained by analysing high-resolution structural MRI scans of 48 twins; specifically, we aimed: i) to test the BW-SA association in a middle-aged adult sample; and ii) to assess whether either depression/anxiety disorders or intellectual quotient (IQ) influence the BW-SA link, using a monozygotic (MZ) twin design to separate environmental and genetic effects. Results Both lower BW and decreased IQ were associated with smaller total and regional cortical SA in adulthood. Within a twin pair, lower BW was related to smaller total cortical and regional SA. In contrast, MZ twin differences in SA were not related to differences in either IQ or depression/anxiety disorders. Conclusion The present study supports findings indicating that i) BW has a long-lasting effect on cortical SA, where some familial and environmental influences alter both foetal growth and brain morphology; ii) uniquely environmental factors affecting BW also alter SA; iii) higher IQ correlates with larger SA; and iv) these effects are not modified by internalizing psychopathology. PMID:26086820

  9. Cyclosporine A, FK506, and NIM811 ameliorate prolonged CBF reduction and impaired neurovascular coupling after cortical spreading depression

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard; Witgen, Brent Marvin; Rasmussen, Peter

    2011-01-01

    that cyclosporine A (CsA), which blocks both mPTP and CaN, ameliorates the persistent reduction of cerebral blood flow (CBF), impaired vascular reactivity, and a persistent rise in the cerebral metabolic rate of oxygen (CMRO(2)) following CSD. In addition to CsA, we used the specific mPTP blocker NIM811......), and neurovascular and neurometabolic coupling were unaffected by all three drugs under control conditions. NIM811 augmented the rise in CBF observed during CSD. Cyclosporine A and FK506 ameliorated the persistent decrease in CBF after CSD. All three drugs prevented disruption of neurovascular coupling after CSD...

  10. Stress hormone corticosterone enhances susceptibility to cortical spreading depression in familial hemiplegic migraine type 1 mutant mice

    NARCIS (Netherlands)

    Shyti, Reinald; Eikermann-Haerter, Katharina; van Heiningen, Sandra H.; Meijer, Onno C.; Ayata, Cenk; Joëls, Marian; Ferrari, Michel D.; van den Maagdenberg, Arn M J M; Tolner, Else A.

    2015-01-01

    Stress is a putative migraine trigger, but the pathogenic mechanisms involved are unknown. Stress and stress hormones increase neuronal excitability by enhancing glutamatergic neurotransmission, but inhibitory effects have also been reported. We hypothesise that an acute rise in stress hormones, suc

  11. InSAR analysis of diking and incipient oceanic spreading in the Danakil depression of the northern Afar rift

    Science.gov (United States)

    Gomez, F. G.; Tesfaye, S.

    2011-12-01

    The Danakil depression in the northern part of the Afar rift is a location of incipient oceanic spreading. Deformation associated with recent magmatic events provides a view of the incremental stages in rifting. Using Interferometric Synthetic Aperture Radar (InSAR) and geodetic modeling, this study assesses magmatic events that occurred in October 2004 and November 2008 in the axial graben of the Danakil depression. The study utilized C-band Envisat ASAR imagery and L-band ALOS PALSAR imagery. Both events involve deflation of magma chambers and intrusion of NNW-SSE striking dikes. The 2004 event took place in the Dallol area and involved ~5 km deep magmatic source and a SSE-propagating dike that opens approximately 80 - 120 cm - this contrasts with seismological results suggesting a 20 km depth with primarily normal faulting. The 2008 event occurred on the northern segment of the Erta Ale volcanic range between Alu and Dalafillal volcanic centers. Available image data permitted assessing pre- and post-event deformation, as well as the main eruption. Interferograms spanning the 2008 eruption image the deflation of a 3 - 4 km deep magmatic source, as well as dilatation of a SSE-striking dike. Additionally, the erupted lava flow is evident as a decorrelated region along the northeast flank of the fissure event. Prior to the eruption, the inflation of the magmatic chamber is imaged, and after the eruption, resurgence of the magma chamber is also documented. Furthermore, post-eruption interferograms also document the contraction and cooling of the lava flow, which facilitates 1-dimensional modeling of the thickness of the flow and calculation of the volume of the effusive component of the eruption. In both cases, aseismic deformation dominates - i.e., the seismologically measured moment is significantly less than the geodetically observed moment: ~25% for the 2004 event and 10% for the 2008 event. Magnitudes of incremental extension are then compared with regional

  12. Lower cortical serotonin 2A receptors in major depressive disorder, suicide and in rats after administration of imipramine.

    Science.gov (United States)

    Dean, Brian; Tawadros, Nahed; Seo, Myoung Suk; Jeon, Won Je; Everall, Ian; Scarr, Elizabeth; Gibbons, Andrew

    2014-06-01

    We have attempted to replicate studies showing higher levels of serotonin 2A receptors (HTR2A) in the cortex of people with mood disorders and to determine the effects of treating rats with antidepressant drugs on levels of that receptor. In situ [3H]ketanserin binding and autoradiography was used to measure levels of HTR2A in Brodmann's area (BA) 46 and 24 from people with major depressive disorders (MDD, n = 16), bipolar disorders (BD, n = 14) and healthy controls (n = 14) as well as the central nervous system (CNS) of rats (20 per treatment arm) treated for 10 or 28 d with fluoxetine (10 mg/kg/d) or imipramine (20 mg/kg/d). Compared with controls, HTR2A were lower in BA 24, but not BA 46, from people with MDD (p = 0.005); HTR2A were not changed in BD. Levels of HTR2A were lower in BA 24 (p = 0.007), but not BA 46, from people who had died by suicide. Finally, levels of HTR2A were lower in the CNS of rats treated with imipramine, but not fluoxetine, for 28 d, but not 10 d. From our current and previous data we conclude cortical HTR2A are lower in schizophrenia, MDD, people with mood disorders who died by suicide, rats treated with some antipsychotic or some antidepressant drugs. As levels of cortical HTR2A can be affected by the aetiologies of different disorders and mechanisms of action of different drugs, a better understanding of how such changes can occur needs to be elucidated.

  13. Decreased occipital cortical glutamate levels in response to successful cognitive-behavioral therapy and pharmacotherapy for major depressive disorder.

    Science.gov (United States)

    Abdallah, Chadi G; Niciu, Mark J; Fenton, Lisa R; Fasula, Madonna K; Jiang, Lihong; Black, Anne; Rothman, Douglas L; Mason, Graeme F; Sanacora, Gerard

    2014-01-01

    Previous studies have demonstrated that antidepressant medication and electroconvulsive therapy increase occipital cortical γ-aminobutyric acid (GABA) in major depressive disorder (MDD), but a small pilot study failed to show a similar effect of cognitive-behavioral therapy (CBT) on occipital GABA. In light of these findings we sought to determine if baseline GABA levels predict treatment response and to broaden the analysis to other metabolites and neurotransmitters in this larger study. A total of 40 MDD outpatients received baseline proton magnetic resonance spectroscopy (1H-MRS), and 30 subjects completed both pre- and post-CBT 1H-MRS; 9 CBT nonresponders completed an open-label medication phase followed by an additional/3rd 1H-MRS. The magnitude of treatment response was correlated with occipital amino acid neurotransmitter levels. Baseline GABA did not predict treatment outcome. Furthermore, there was no significant effect of CBT on GABA levels. However, we found a significant group × time interaction (F1, 28 = 6.30, p = 0.02), demonstrating reduced glutamate in CBT responders, with no significant glutamate change in CBT nonresponders. These findings corroborate the lack of effect of successful CBT on occipital cortical GABA levels in a larger sample. A reduction in glutamate levels following treatment, on the other hand, correlated with successful CBT and antidepressant medication response. Based on this finding and other reports, decreased occipital glutamate may be an antidepressant response biomarker. Healthy control comparator and nonintervention groups may shed light on the sensitivity and specificity of these results.

  14. Alterations in visual cortical activation and connectivity with prefrontal cortex during working memory updating in major depressive disorder.

    Science.gov (United States)

    Le, Thang M; Borghi, John A; Kujawa, Autumn J; Klein, Daniel N; Leung, Hoi-Chung

    2017-01-01

    The present study examined the impacts of major depressive disorder (MDD) on visual and prefrontal cortical activity as well as their connectivity during visual working memory updating and related them to the core clinical features of the disorder. Impairment in working memory updating is typically associated with the retention of irrelevant negative information which can lead to persistent depressive mood and abnormal affect. However, performance deficits have been observed in MDD on tasks involving little or no demand on emotion processing, suggesting dysfunctions may also occur at the more basic level of information processing. Yet, it is unclear how various regions in the visual working memory circuit contribute to behavioral changes in MDD. We acquired functional magnetic resonance imaging data from 18 unmedicated participants with MDD and 21 age-matched healthy controls (CTL) while they performed a visual delayed recognition task with neutral faces and scenes as task stimuli. Selective working memory updating was manipulated by inserting a cue in the delay period to indicate which one or both of the two memorized stimuli (a face and a scene) would remain relevant for the recognition test. Our results revealed several key findings. Relative to the CTL group, the MDD group showed weaker postcue activations in visual association areas during selective maintenance of face and scene working memory. Across the MDD subjects, greater rumination and depressive symptoms were associated with more persistent activation and connectivity related to no-longer-relevant task information. Classification of postcue spatial activation patterns of the scene-related areas was also less consistent in the MDD subjects compared to the healthy controls. Such abnormalities appeared to result from a lack of updating effects in postcue functional connectivity between prefrontal and scene-related areas in the MDD group. In sum, disrupted working memory updating in MDD was revealed by

  15. Alterations in visual cortical activation and connectivity with prefrontal cortex during working memory updating in major depressive disorder

    Directory of Open Access Journals (Sweden)

    Thang M. Le

    2017-01-01

    Full Text Available The present study examined the impacts of major depressive disorder (MDD on visual and prefrontal cortical activity as well as their connectivity during visual working memory updating and related them to the core clinical features of the disorder. Impairment in working memory updating is typically associated with the retention of irrelevant negative information which can lead to persistent depressive mood and abnormal affect. However, performance deficits have been observed in MDD on tasks involving little or no demand on emotion processing, suggesting dysfunctions may also occur at the more basic level of information processing. Yet, it is unclear how various regions in the visual working memory circuit contribute to behavioral changes in MDD. We acquired functional magnetic resonance imaging data from 18 unmedicated participants with MDD and 21 age-matched healthy controls (CTL while they performed a visual delayed recognition task with neutral faces and scenes as task stimuli. Selective working memory updating was manipulated by inserting a cue in the delay period to indicate which one or both of the two memorized stimuli (a face and a scene would remain relevant for the recognition test. Our results revealed several key findings. Relative to the CTL group, the MDD group showed weaker postcue activations in visual association areas during selective maintenance of face and scene working memory. Across the MDD subjects, greater rumination and depressive symptoms were associated with more persistent activation and connectivity related to no-longer-relevant task information. Classification of postcue spatial activation patterns of the scene-related areas was also less consistent in the MDD subjects compared to the healthy controls. Such abnormalities appeared to result from a lack of updating effects in postcue functional connectivity between prefrontal and scene-related areas in the MDD group. In sum, disrupted working memory updating in MDD was

  16. Anxiety and Depression Among Sexual Minority Women and Men in Sweden: Is the Risk Equally Spread Within the Sexual Minority Population?

    Science.gov (United States)

    Björkenstam, Charlotte; Björkenstam, Emma; Andersson, Gunnar; Cochran, Susan; Kosidou, Kyriaki

    2017-03-01

    Sexual minority individuals have a higher risk of anxiety and depression compared with heterosexuals. However, whether the higher risk is spread equally across the sexual minority population is not clear. To investigate the association between sexual orientation and self-reported current anxiety and a history of diagnosis of depression, paying particular attention to possible subgroup differences in risks within the sexual minority population, stratified by sex and to examine participants' history of medical care for anxiety disorders and depression. We conducted a population-based study of 874 lesbians and gays, 841 bisexuals, and 67,980 heterosexuals recruited in 2010 in Stockholm County. Data were obtained from self-administered surveys that were linked to nationwide registers. By using logistic regression, we compared risks of current anxiety, histories of diagnosed depression, and register-based medical care for anxiety and/or depression in lesbian and gay, bisexual, and heterosexual individuals. Bisexual women and gay men were more likely to report anxiety compared with their heterosexual peers. Bisexual individuals and gay men also were more likely to report a past diagnosis of depression. All sexual minority groups had an increased risk of having used medical care for anxiety and depression compared with heterosexuals, with bisexual women having the highest risk. Bisexual women appear to be a particularly vulnerable sexual minority group. Advocating for non-discrimination and protections for lesbian, gay, and bisexual people is a logical extension of the effort to lower the prevalence of mental illness. Björkenstam C, Björkenstam E, Andersson G, et al. Anxiety and Depression Among Sexual Minority Women and Men in Sweden: Is the Risk Equally Spread Within the Sexual Minority Population? J Sex Med 2017;14:396-403. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  17. Depressants

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Depressants KidsHealth > For Teens > Depressants A A A What's ... How Can Someone Quit? Avoiding Depressants What Are Depressants? Depressants are drugs that calm nerves and relax ...

  18. Decreased subcortical and increased cortical degree centrality in a nonclinical college student sample with subclinical depressive symptoms: a resting-state fMRI study

    Directory of Open Access Journals (Sweden)

    Cuihua Gao

    2016-12-01

    Full Text Available Abnormal functional connectivity (FC at rest has been identified in clinical depressive disorder. However, very few studies have been conducted to understand the underlying neural substrates of subclinical depression. The newly proposed centrality analysis approach has been increasingly used to explore the large-scale brain network of mental diseases. This study aimed to identify the degree centrality (DC alteration of the brain network in subclinical depressive subjects. Thirty-seven candidates with subclinical depression and 34 well-matched healthy controls (HCs were recruited from the same sample of college students. All subjects underwent a resting-state fMRI (rs-fMRI scan to assess the DC of the whole brain. Compared with controls, subclinical depressive subjects displayed decreased DC in the right parahippocampal gyrus (PHG, left PHG/amygdala, and left caudate and elevated DC in the right posterior parietal lobule (PPL, left inferior frontal gyrus (IFG and left middle frontal gyrus (MFG. In addition, by using receiver operating characteristic (ROC analysis, we determined that the DC values in the regions with altered FC between the two groups can be used to differentiate subclinical depressive subjects from HCs. We suggest that decreased DC in subcortical and increased DC in cortical regions might be the neural substrates of subclinical depression.

  19. Decreased Subcortical and Increased Cortical Degree Centrality in a Nonclinical College Student Sample with Subclinical Depressive Symptoms: A Resting-State fMRI Study

    Science.gov (United States)

    Gao, Cuihua; Wenhua, Liu; Liu, Yanli; Ruan, Xiuhang; Chen, Xin; Liu, Lingling; Yu, Shaode; Chan, Raymond C. K.; Wei, Xinhua; Jiang, Xinqing

    2016-01-01

    Abnormal functional connectivity (FC) at rest has been identified in clinical depressive disorder. However, very few studies have been conducted to understand the underlying neural substrates of subclinical depression. The newly proposed centrality analysis approach has been increasingly used to explore the large-scale brain network of mental diseases. This study aimed to identify the degree centrality (DC) alteration of the brain network in subclinical depressive subjects. Thirty-seven candidates with subclinical depression and 34 well-matched healthy controls (HCs) were recruited from the same sample of college students. All subjects underwent a resting-state fMRI (rs-fMRI) scan to assess the DC of the whole brain. Compared with controls, subclinical depressive subjects displayed decreased DC in the right parahippocampal gyrus (PHG), left PHG/amygdala, and left caudate and elevated DC in the right posterior parietal lobule (PPL), left inferior frontal gyrus (IFG) and left middle frontal gyrus (MFG). In addition, by using receiver operating characteristic (ROC) analysis, we determined that the DC values in the regions with altered FC between the two groups can be used to differentiate subclinical depressive subjects from HCs. We suggest that decreased DC in subcortical and increased DC in cortical regions might be the neural substrates of subclinical depression. PMID:27994546

  20. Temporo-spectral imaging of intrinsic optical signals during hypoxia-induced spreading depression-like depolarization.

    Directory of Open Access Journals (Sweden)

    Maria Mané

    Full Text Available Spreading depression (SD is characterized by a sustained near-complete depolarization of neurons, a massive depolarization of glia, and a negative deflection of the extracellular DC potential. These electrophysiological signs are accompanied by an intrinsic optical signal (IOS which arises from changes in light scattering and absorption. Even though the underlying mechanisms are unclear, the IOS serves as non-invasive tool to define the spatiotemporal dynamics of SD in brain slices. Usually the tissue is illuminated by white light, and light reflectance or transmittance is monitored. Using a polychromatic, fast-switchable light source we now performed temporo-spectral recordings of the IOS associated with hypoxia-induced SD-like depolarization (HSD in rat hippocampal slices kept in an interface recording chamber. Recording full illumination spectra (320-680 nm yielded distinct reflectance profiles for the different phases of HSD. Early during hypoxia tissue reflectance decreased within almost the entire spectrum due to cell swelling. HSD was accompanied by a reversible reflectance increase being most pronounced at 400 nm and 460 nm. At 440 nm massive porphyrin absorption (Soret band was detected. Hypotonic solutions, Ca(2+-withdrawal and glial poisoning intensified the reflectance increase during HSD, whereas hypertonic solutions dampened it. Replacement of Cl(- inverted the reflectance increase. Inducing HSD by cyanide distorted the IOS and reflectance at 340-400 nm increased irreversibly. The pronounced changes at short wavelengths (380 nm, 460 nm and their cyanide sensitivity suggest that block of mitochondrial metabolism contributes to the IOS during HSD. For stable and reliable IOS recordings during HSD wavelengths of 460-560 nm are recommended.

  1. Dopaminergic neurotransmission dysfunction induced by amyloid-β transforms cortical long-term potentiation into long-term depression and produces memory impairment.

    Science.gov (United States)

    Moreno-Castilla, Perla; Rodriguez-Duran, Luis F; Guzman-Ramos, Kioko; Barcenas-Femat, Alejandro; Escobar, Martha L; Bermudez-Rattoni, Federico

    2016-05-01

    Alzheimer's disease (AD) is a neurodegenerative condition manifested by synaptic dysfunction and memory loss, but the mechanisms underlying synaptic failure are not entirely understood. Although dopamine is a key modulator of synaptic plasticity, dopaminergic neurotransmission dysfunction in AD has mostly been associated to noncognitive symptoms. Thus, we aimed to study the relationship between dopaminergic neurotransmission and synaptic plasticity in AD models. We used a transgenic model of AD (triple-transgenic mouse model of AD) and the administration of exogenous amyloid-β (Aβ) oligomers into wild type mice. We found that Aβ decreased cortical dopamine levels and converted in vivo long-term potentiation (LTP) into long-term depression (LTD) after high-frequency stimulation delivered at basolateral amygdaloid nucleus-insular cortex projection, which led to impaired recognition memory. Remarkably, increasing cortical dopamine and norepinephrine levels rescued both high-frequency stimulation -induced LTP and memory, whereas depletion of catecholaminergic levels mimicked the Aβ-induced shift from LTP to LTD. Our results suggest that Aβ-induced dopamine depletion is a core mechanism underlying the early synaptopathy and memory alterations observed in AD models and acts by modifying the threshold for the induction of cortical LTP and/or LTD. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Cortical abnormalities in adults and adolescents with major depression based on brain scans from 20 cohorts worldwide in the ENIGMA Major Depressive Disorder Working Group

    NARCIS (Netherlands)

    Schmaal, L; Hibar, D P; Sämann, P G; Hall, G B; Baune, B T; Jahanshad, N; Cheung, J W; van Erp, T G M; Bos, D; Ikram, M A; Vernooij, M W; Niessen, W J; Tiemeier, H; Hofman, A.; Wittfeld, K; Grabe, H J; Janowitz, D; Bülow, R; Selonke, M; Völzke, H; Grotegerd, D; Dannlowski, U; Arolt, V; Opel, N; Heindel, W; Kugel, H; Hoehn, D; Czisch, M; Couvy-Duchesne, B; Rentería, M E; Strike, L T; Wright, M J; Mills, N T; de Zubicaray, G I; McMahon, K L; Medland, S E; Martin, N G; Gillespie, N A; Goya-Maldonado, R; Gruber, O; Krämer, B; Hatton, S N; Lagopoulos, J; Hickie, I B; Frodl, T; Carballedo, A; Frey, E M; van Velzen, L S; Penninx, B W J H; van Tol, M-J; van der Wee, N J; Davey, C G; Harrison, B J; Mwangi, B; Cao, B; Soares, J C; Veer, I M; Walter, H; Schoepf, D; Zurowski, B; Konrad, C; Schramm, E; Normann, C; Schnell, K; Sacchet, M D; Gotlib, I H; MacQueen, G M; Godlewska, B R; Nickson, T; McIntosh, A M; Papmeyer, M; Whalley, H C; Hall, J; Sussmann, J E; Li, M; Walter, M; Aftanas, L; Brack, I; Bokhan, N A; Thompson, P M; Veltman, D J

    2016-01-01

    The neuro-anatomical substrates of major depressive disorder (MDD) are still not well understood, despite many neuroimaging studies over the past few decades. Here we present the largest ever worldwide study by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) Major Depressive Diso

  3. Depression

    Science.gov (United States)

    ... overview URL of this page: //medlineplus.gov/ency/article/003213.htm Depression - overview To use the sharing features on this ... older adults Major depression Persistent depressive disorder Postpartum depression Premenstrual ... Review Date 1/4/2016 Updated by: Timothy Rogge, ...

  4. Depression

    DEFF Research Database (Denmark)

    Kessing, Lars Veddel; Bukh, Jens Otto Drachmann

    2014-01-01

    The prevalence of depression is not clearly established, but estimated to 3-4% in a Danish questionnaire study. Lifetime's prevalences of 12-17% are reported in other community samples. In the current diagnostic system depression is defined categorically and operationally. It has been argued......, that these diagnostic criteria represent an oversimplification, which has blurred the concept of depression. We suggest a greater emphasis on the depressed mood as the core symptom of depression, which may increase the specificity of the diagnosis. Furthermore, basic principles for the treatment of depression...

  5. Depression

    DEFF Research Database (Denmark)

    Kessing, Lars Veddel; Bukh, Jens Drachmann

    2014-01-01

    , that these diagnostic criteria represent an oversimplification, which has blurred the concept of depression. We suggest a greater emphasis on the depressed mood as the core symptom of depression, which may increase the specificity of the diagnosis. Furthermore, basic principles for the treatment of depression......The prevalence of depression is not clearly established, but estimated to 3-4% in a Danish questionnaire study. Lifetime's prevalences of 12-17% are reported in other community samples. In the current diagnostic system depression is defined categorically and operationally. It has been argued...

  6. Depressants

    Science.gov (United States)

    ... judgment and mental functioning nausea and vomiting memory loss (depressants can cause users to have no memory of events that happened while they were under the influence) Long-Term Effects When people misuse depressants over a long ...

  7. L-Arginina facilita a depressão alastrante cortical, de forma dependente da dose, em ratos nutridos e precocemente desnutridos

    OpenAIRE

    Maria Silva de Seixas Maia, Luciana

    2008-01-01

    A L-Arginina atua como precursor do óxido nítrico, que possui várias funções no sistema nervoso, e cuja síntese pode ser modulada pela ingestão de L-Arginina. Em trabalho anterior deste laboratório (Frazão, 2004), demonstrou-se que a administração de 300mg/kg/dia de L-Arginina durante o aleitamento facilita, em animais bem nutridos adultos (90-120 dias), a propagação do fenômeno da depressão alastrante cortical (DAC). Neste trabalho, ratos lactentes, nutridos e desnutridos, foram tratados por...

  8. Dieta Hipercalórica e Hiperlipídica em diferentes Fases da Vida:Efeitos Sobre a Depressão Alastrante Cortical em Ratos Adultos

    OpenAIRE

    GERMANO, Paula Catirina Pereira da Silva

    2012-01-01

    Condições nutricionais no início da vida constituem um fator ambiental que pode influenciar um fenômeno eletrofisiológico do cérebro chamado depressão alastrante cortical (DAC). Objetivo - Avaliar os efeitos da ingestão de dieta hipercalórica e hiperlipídica durante a lactação, na vida adulta e, desde a lactação até a idade adulta, sobre as características da DAC nos ratos adultos. Métodos - Os animais foram divididos de acordo com seu tratamento dietético específico: 1) grupo Contro...

  9. Depression

    DEFF Research Database (Denmark)

    Cizza, G; Ravn, Pernille; Chrousos, G P

    2001-01-01

    Existing studies of the relationship between depression and osteoporosis have been heterogeneous in their design and use of diagnostic instruments for depression, which might have contributed to the different results on the comorbidity of these two conditions. Nevertheless, these studies reveal...... a strong association between depression and osteoporosis. Endocrine factors such as depression-induced hypersecretion of corticotropin-releasing hormone and hypercortisolism, hypogonadism, growth hormone deficiency and increased concentration of circulating interleukin 6, might play a crucial role...... in the bone loss observed in subjects suffering from major depression....

  10. Depression

    DEFF Research Database (Denmark)

    Pouwer, Frans

    2017-01-01

    There is ample evidence that depression is000  a common comorbid health issue in people with type 1 or type 2 diabetes. Reviews have also concluded that depression in diabetes is associated with higher HbA1c levels, less optimal self-care behaviours, lower quality of life, incident vascular...... complications and higher mortality rates. However, longitudinal studies into the course of depression in people with type 1 diabetes remain scarce. In this issue of Diabetologia, Kampling and colleagues (doi: 10.1007/s00125-016-4123-0 ) report the 5 year trajectories of depression in adults with newly diagnosed...... type 1 diabetes (mean age, 28 years). Their baseline results showed that shortly after the diagnosis of type 1 diabetes a major depressive episode was diagnosed in approximately 6% of participants, while 8% suffered from an anxiety disorder. The longitudinal depression data showed that, in a 5 year...

  11. Depression.

    Science.gov (United States)

    Strock, Margaret

    Approximately ten percent of the population suffers from a depressive illness each year. Although the economic cost is high, the cost in human suffering is immeasurable. To help educate the population about this disorder, this paper presents a definition of depression and its common manifestations. The symptoms that people often experience are…

  12. Depression

    DEFF Research Database (Denmark)

    Johansen, Jon O. J.

    2013-01-01

    Nyhederne er fulde af historier om depression. Overskrifter som: ’Danskerne propper sig med lykkepiller’ eller ‘depression er stadigvæk tabu’ går tit igen i dagspressen. Men hvor er nuancerne, og hvorfor gider vi læse de samme historier igen og igen? Måske er det fordi, vores egne forestillinger er...

  13. Spreading effect of tDCS in individuals with attention-deficit/hyperactivity disorder as shown by functional cortical networks: a randomized, double-blind, sham-controlled trial

    Directory of Open Access Journals (Sweden)

    Camila eCosmo

    2015-08-01

    Full Text Available Transcranial direct current stimulation (tDCS is known to modulate spontaneous neural network excitability. The cognitive improvement observed in previous trials raises the potential of this technique as a possible therapeutic tool for use in attention-deficit/hyperactivity disorder (ADHD population. However, to explore the potential of this technique as a treatment approach the functional parameters of brain connectivity and the extent of its effects need to be more fully investigated.The aim of this study was to investigate a functional cortical network model based on electroencephalographic activity for studying the dynamic patterns of brain connectivity modulated by tDCS and the distribution of its effects in individuals with attention-deficit/hyperactivity disorder (ADHD.Sixty ADHD patients participated in a parallel, randomized, double-blind, sham-controlled trial. Individuals underwent a single session of sham or anodal tDCS at 1 mA of current intensity over the left dorsolateral prefrontal cortex for 20 minutes. The acute effects of stimulation on brain connectivity were assessed using the functional cortical network model based on electroencephalography (EEG activity.Comparing the weighted node degree within groups prior to and following the intervention, a statistically significant difference was found in the electrodes located on the target and correlated areas in the active group (p<0.05, while no statistically significant results were found in the sham group (p ≥0.05; paired-sample Wilcoxon signed rank test. Anodal tDCS increased functional brain connectivity in individuals with ADHD compared to data recorded in the baseline resting state. In addition, although some studies have suggested that the effects of tDCS are selective, the present findings show that its modulatory activity spreads. Further studies need to be performed to investigate the dynamic patterns and physiological mechanisms underlying the modulatory effects of tDCS.

  14. Depression

    Science.gov (United States)

    ... Different people have different symptoms. Some symptoms of depression include: Persistent sad, anxious, or “empty” mood Feelings of hopelessness or pessimism Feelings of guilt, worthlessness, or helplessness ...

  15. Depression

    Science.gov (United States)

    ... caring for children and aging parents, abuse, and poverty may trigger depression in some people. Medical illness – ... federal government website managed by the Office on Women’s Health in the Office of the Assistant Secretary ...

  16. Depression.

    Science.gov (United States)

    McCarron, Robert M; Vanderlip, Erik R; Rado, Jeffrey

    2016-10-04

    This issue provides a clinical overview of depression, focusing on screening, diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  17. [Cortical blindness].

    Science.gov (United States)

    Chokron, S

    2014-02-01

    Cortical blindness refers to a visual loss induced by a bilateral occipital lesion. The very strong cooperation between psychophysics, cognitive psychology, neurophysiology and neuropsychology these latter twenty years as well as recent progress in cerebral imagery have led to a better understanding of neurovisual deficits, such as cortical blindness. It thus becomes possible now to propose an earlier diagnosis of cortical blindness as well as new perspectives for rehabilitation in children as well as in adults. On the other hand, studying complex neurovisual deficits, such as cortical blindness is a way to infer normal functioning of the visual system.

  18. Elevated serotonin transporter binding in depressed patients with Parkinson's disease: a preliminary PET study with [11C]DASB.

    Science.gov (United States)

    Boileau, Isabelle; Warsh, Jerry J; Guttman, Mark; Saint-Cyr, Jean A; McCluskey, Tina; Rusjan, Pablo; Houle, Sylvain; Wilson, Alan A; Meyer, Jeffrey H; Kish, Stephen J

    2008-09-15

    This study investigated whether abnormalities in serotonin transporter binding occur in Parkinson's disease (PD) patients with concurrent depression. We estimated serotonin transporter levels in seven clinically depressed early-stage PD patients and in seven healthy matched-control subjects during a single positron emission tomography (PET) scan with the serotonin transporter radioligand, [(11)C]DASB. Depressed PD patients displayed a wide-spread increase (8-68%) in [(11)C]DASB specific binding outside of the striatum, which was significant in dorsolateral (37%) and prefrontal (68%) cortices. Elevated [(11)C]DASB binding was positively correlated with depressive symptoms but not with disease severity or duration. Compatible with recent PET/[(11)C]DASB findings in major depression, the present preliminary data suggest that increased [(11)C]DASB binding, possibly reflecting greater serotonin transporter density (up-regulation), might be a pathological feature of depression in Parkinson's disease-and possibly a characteristic of depressive illness in general.

  19. Cortico-cortical communication dynamics

    Directory of Open Access Journals (Sweden)

    Per E Roland

    2014-05-01

    Full Text Available IIn principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG, and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review.

  20. Regional cortical thinning of the orbitofrontal cortex in medication-naïve female patients with major depressive disorder is not associated with MAOA-uVNTR polymorphism

    OpenAIRE

    Won, Eunsoo; Choi, Sunyoung; Kang, June; Lee, Min-Soo; Ham, Byung-Joo

    2016-01-01

    Background Orbitofrontal cortex alterations have been suggested to underlie the impaired mood regulation in depression. MAOA-uVNTR (monoamine oxidase A-upstream variable number of tandem repeats) polymorphism has been reported to be associated with major depressive disorder by various studies. The influence of MAOA-uVNTR genotype on function and structure of the orbitofrontal cortex has previously been reported. In this study, we investigated the difference in orbitofrontal cortex thickness b...

  1. Interest of targeting either cortical area Brodmann 9 or 46 in rTMS treatment for depression: a preliminary randomized study.

    Science.gov (United States)

    Trojak, Benoit; Meille, Vincent; Jonval, Lysiane; Schuffenecker, Nicolas; Haffen, Emmanuel; Schwan, Raymund; Bonin, Bernard; Chauvet-Gelinier, Jean-Christophe

    2014-12-01

    To assess the interest of specifically targeting Brodmann Areas (BA) 9 or 46 for rTMS treatment of depression. Patients with Treatment-Resistant Depression were randomly assigned to two treatment groups to receive either rTMS on BA 9 or on BA 46. Each patient underwent 10 sessions of 1Hz-rTMS for 2weeks. The Hamilton and Montgomery-Asberg Depression Rating Scales (HDRS, MADRS) were used under blind conditions to assess the therapeutic response (50% improvement). A Wilcoxon signed-rank test was used to compare the depression rating scales scores obtained before and after the 10 rTMS sessions for each of the two groups. The therapeutic results in the two groups were compared using the Mann-Whitney-Wilcoxon test. We also reported the effect sizes using Hedges's g. Fifteen patients were included. Stimulation of both BA 9 (n=7) and BA 46 (n=8) led to similar therapeutic responses in the two groups (with moderate effect size), such as the mean decrease in HDRS (BA 9: p=0.015; BA 46: p=0.010) and MADRS (BA 9: p=0.042; BA 46: p=0.038) scores. Our results do not come out in favor of one or the other BA. Stimulation of BA 9 and BA 46 appears to be equally effective in the treatment of depression. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  2. Hot spots and labyrinths: Why cortical neuromodulation for episodic migraine with aura should be personalized

    Directory of Open Access Journals (Sweden)

    Markus A Dahlem

    2015-03-01

    Full Text Available Stimulation protocols for medical devices should be rationally designed. For episodic migraine with aura we outline model-based design strategies towards preventive and acute therapies using stereotactic cortical neuromodulation. To this end, we regard a localized spreading depression (SD wave segment as a central element in migraine pathophysiology. To describe nucleation and propagation features of the SD wave segment, we define the new concepts of cortical hot spots and labyrinths, respectively. In particular, we firstly focus exclusively on curvature-induced dynamical properties by studying a generic reaction-diffusion model of SD on the folded cortical surface. This surface is described with increasing level of details, including finally personalized simulations using patient's magnetic resonance imaging (MRI scanner readings. At this stage, the only relevant factor that can modulate nucleation and propagation paths is the Gaussian curvature, which has the advantage of being rather readily accessible by MRI. We conclude with discussing further anatomical factors, such as areal, laminar, and cellular heterogeneity, that in addition to and in relation to Gaussian curvature determine the generalized concept of cortical hot spots and labyrinths as target structures for neuromodulation. Our numerical simulations suggest that these target structures are like fingerprints, they are individual features of each migraine sufferer. The goal in the future will be to provide individualized neural tissue simulations. These simulations should predict the clinical data and therefore can also serve as a test bed for exploring stereotactic cortical neuromodulation.

  3. Self-Referential Thinking, Suicide, and Function of the Cortical Midline Structures and Striatum in Mood Disorders: Possible Implications for Treatment Studies of Mindfulness-Based Interventions for Bipolar Depression

    Directory of Open Access Journals (Sweden)

    William R. Marchand

    2012-01-01

    Full Text Available Bipolar depression is often refractory to treatment and is frequently associated with anxiety symptoms and elevated suicide risk. There is a great need for adjunctive psychotherapeutic interventions. Treatments with effectiveness for depressive and anxiety symptoms as well as suicide-related thoughts and behaviors would be particularly beneficial. Mindfulness-based interventions hold promise, and studies of these approaches for bipolar disorder are warranted. The aim of this paper is to provide a conceptual background for such studies by reviewing key findings from diverse lines of investigation. Results of that review indicate that cortical midline structures (CMS appear to link abnormal self-referential thinking to emotional dysregulation in mood disorders. Furthermore, CMS and striatal dysfunction may play a role in the neuropathology underlying suicide-related thoughts and behaviors. Thus, combining studies of mindfulness interventions targeting abnormal self-referential thinking with functional imaging of CMS and striatal function may help delineate the neurobiological mechanisms of action of these treatments.

  4. Spreading Depression, Spreading Depolarizations, and the Cerebral Vasculature

    DEFF Research Database (Denmark)

    Ayata, Cenk; Lauritzen, Martin

    2015-01-01

    slowly at a rate of only millimeters per minute by way of grey matter contiguity, irrespective of functional or vascular divisions, and lasts up to a minute in otherwise normal tissue. As such, SD is a radically different breed of electrophysiological activity compared with everyday neural activity...

  5. Cortical and Subcortical Grey and White Matter Atrophy in Myotonic Dystrophies Type 1 and 2 Is Associated with Cognitive Impairment, Depression and Daytime Sleepiness

    Science.gov (United States)

    Prehn, Christian; Krogias, Christos; Schneider, Ruth; Klein, Jan; Gold, Ralf; Lukas, Carsten

    2015-01-01

    Objectives Central nervous system involvement is one important clinical aspect of myotonic dystrophy type 1 and 2 (DM1 and DM2). We assessed CNS involvement DM1 and DM2 by 3T MRI and correlated clinical and neuocognitive symptoms with brain volumetry and voxel-based morphometry (VBM). Methods 12 patients with juvenile or classical DM1 and 16 adult DM2 patients underwent 3T MRI, a thorough neurological and neuropsychological examination and scoring of depression and daytime sleepiness. Volumes of brain, ventricles, cerebellum, brainstem, cervical cord, lesion load and VBM results of the patient groups were compared to 33 matched healthy subjects. Results Clinical symptoms were depression (more pronounced in DM2), excessive daytime sleepiness (more pronounced in DM1), reduced attention and flexibility of thinking, and deficits of short-term memory and visuo-spatial abilities in both patient groups. Both groups showed ventricular enlargement and supratentorial GM and WM atrophy, with prevalence for more GM atrophy and involvement of the motor system in DM1 and more WM reduction and affection of limbic structures in DM2. White matter was reduced in DM1 in the splenium of the corpus callosum and in left-hemispheric WM adjacent to the pre- and post-central gyrus. In DM2, the bilateral cingulate gyrus and subgyral medio-frontal and primary somato-sensory WM was affected. Significant structural-functional correlations of morphological MRI findings (global volumetry and VBM) with clinical findings were found for reduced flexibility of thinking and atrophy of the left secondary visual cortex in DM1 and of distinct subcortical brain structures in DM2. In DM2, depression was associated with brainstem atrophy, Daytime sleepiness correlated with volume decrease in the middle cerebellar peduncles, pons/midbrain and the right medio-frontal cortex. Conclusion GM and WM atrophy was significant in DM1 and DM2. Specific functional-structural associations related morphological changes

  6. 首发未治疗成人重型抑郁症患者皮层厚度的MRI研究%Brain cortical thickness abnormalities in first-episode, never-medicated, adult major depressive disorder patients

    Institute of Scientific and Technical Information of China (English)

    赵又瑾; 陈丽舟; 张文静; 孙怀强; 邱丽华; 孙学礼; 吕粟; 龚启勇

    2016-01-01

    目的:探索首发未治疗成人重型抑郁症(MDD)患者皮层厚度是否存在异常及其与病程及临床症状的相关性。方法研究纳入2013年3月至2015年8月间招募的37例MDD患者(患者组)及41名健康志愿者(对照组)。所有受试者通过三维扰相梯度回波(3D-SPGR)序列获得3D T1图像。应用FreeSurfer软件完成3D-SPGR图像皮层表面的建造,然后通过自动重建表面、转换、高分辨个体间校准步骤来测量整个皮层的厚度。最后采用一般线性模型对2组皮层厚度进行比较,将患者组全脑皮层厚度与病程及临床评分进行相关分析。结果与对照组比较,MDD患者左侧前、中扣带回,双侧中央前回,左侧中央旁小叶,双侧顶上回,左侧颞极及右侧枕外叶皮层厚度增加(皮层厚度1.89~2.87 mm,皮层表面积34~384 mm2,P0.05)。结论首发未治疗MDD患者皮层厚度改变的脑区主要位于前额叶-边缘系统。%Objective Present study aimed to characterize the alteration of cortical thickness in first-episode, never-medicated, adult patients with major depressive disorder (MDD), and explore whether such deficits were related with their disease duration and clinical symptom severity. Methods Thirty-seven adult MDD patients were recruited from March 2013 to August 2015 as patient group, and 41 healthy volunteers were as control group. All the patients underwent three-dimensional spoiled gradient recalled (3D-SPGR) sequences, and the images were acquired. Constructions of the cortical surface were developed from 3D-SPGR images using FreeSurfer software, and the thickness of the entire cortex was measured according to the automated surface reconstruction, transformation, and high-resolution inter-subject alignment procedures. Finally, cortical thickness was compared between the two groups, and the relativity between clinical symptom severity, disease progression and clinical scores were analyzed

  7. Persistent Aura with Small Occipital Cortical Infarction: Implications for Migraine Pathophysiology

    Directory of Open Access Journals (Sweden)

    Sam Thissen

    2014-08-01

    Full Text Available Objective: The pathophysiology of migraine with aura is thought to be related to cortical spreading depression and cortical hypersensitivity, in which inhibitory interneurons may play a role. Persistent migraine aura (PMA without infarction is defined as auras that last longer than 1 week in the absence of infarction. We describe a case of persistent aura with a small occipital cortical infarction and discuss implications of this case and PMA for pathophysiological concepts of migrainous auras. Methods: We present a case and discuss the implications for pathophysiological concepts. Results: The case presented cannot be diagnosed as PMA as the patient was found to have an occipital cortical infarction with hypoactivity on fluorodeoxyglucose-positron emission tomography. Nevertheless, the patient suffered from persistent aura (with infarction. We argue that the infarction may have been responsible for an increased imbalance in one of the primary visual cortex networks that was already hyperexcitable due to the migraine aura condition. Conclusion: PMA with occipital infarction has not been reported previously. We believe the findings of the present case and PMA cases reported in the past may support the intracortical disinhibition hypothesis in migraine.

  8. Cortical Visual Impairment

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased visual ...

  9. Defective glutamate and K+ clearance by cortical astrocytes in familial hemiplegic migraine type 2.

    Science.gov (United States)

    Capuani, Clizia; Melone, Marcello; Tottene, Angelita; Bragina, Luca; Crivellaro, Giovanna; Santello, Mirko; Casari, Giorgio; Conti, Fiorenzo; Pietrobon, Daniela

    2016-08-01

    Migraine is a common disabling brain disorder. A subtype of migraine with aura (familial hemiplegic migraine type 2: FHM2) is caused by loss-of-function mutations in α2 Na(+),K(+) ATPase (α2 NKA), an isoform almost exclusively expressed in astrocytes in adult brain. Cortical spreading depression (CSD), the phenomenon that underlies migraine aura and activates migraine headache mechanisms, is facilitated in heterozygous FHM2-knockin mice with reduced expression of α2 NKA The mechanisms underlying an increased susceptibility to CSD in FHM2 are unknown. Here, we show reduced rates of glutamate and K(+) clearance by cortical astrocytes during neuronal activity and reduced density of GLT-1a glutamate transporters in cortical perisynaptic astrocytic processes in heterozygous FHM2-knockin mice, demonstrating key physiological roles of α2 NKA and supporting tight coupling with GLT-1a. Using ceftriaxone treatment of FHM2 mutants and partial inhibition of glutamate transporters in wild-type mice, we obtain evidence that defective glutamate clearance can account for most of the facilitation of CSD initiation in FHM2-knockin mice, pointing to excessive glutamatergic transmission as a key mechanism underlying the vulnerability to CSD ignition in migraine.

  10. Depression (Major Depressive Disorder)

    Science.gov (United States)

    ... generally miserable or unhappy without really knowing why. Depression symptoms in children and teens Common signs and ... in normal activities, and avoidance of social interaction. Depression symptoms in older adults Depression is not a ...

  11. Effect of mescaline on single cortical neurones.

    Science.gov (United States)

    Bradshaw, C M; Roberts, M H; Szabadi, E

    1971-12-01

    The effects of mescaline upon single cortical neurones were studied, using the microiontophoretic technique. Mescaline elicited excitatory and depressant responses similar to those evoked by noradrenaline (NA) and 5-hydroxytryptamine (5-HI). The responses to NA and mescaline were usually in the same direction, the neurone being either excited by both drugs or depressed by both drugs. The correlation between the effects of mescaline and 5-HT, however, was less consistent. The beta-adrenoceptor blocking agent MJ-1999 and the 5-HT antagonist methysergide were both effective in antagonizing mescaline responses.

  12. Information in CDS Spreads

    NARCIS (Netherlands)

    L. Norden (Lars)

    2014-01-01

    textabstractWe investigate how public and private information drives corporate CDS spreads before rating announcements. We find that CDS spreads of firms with higher news intensity move significantly earlier and stronger before rating announcements, which can be explained with public information fro

  13. The spreading of disorder.

    Science.gov (United States)

    Keizer, Kees; Lindenberg, Siegwart; Steg, Linda

    2008-12-12

    Imagine that the neighborhood you are living in is covered with graffiti, litter, and unreturned shopping carts. Would this reality cause you to litter more, trespass, or even steal? A thesis known as the broken windows theory suggests that signs of disorderly and petty criminal behavior trigger more disorderly and petty criminal behavior, thus causing the behavior to spread. This may cause neighborhoods to decay and the quality of life of its inhabitants to deteriorate. For a city government, this may be a vital policy issue. But does disorder really spread in neighborhoods? So far there has not been strong empirical support, and it is not clear what constitutes disorder and what may make it spread. We generated hypotheses about the spread of disorder and tested them in six field experiments. We found that, when people observe that others violated a certain social norm or legitimate rule, they are more likely to violate other norms or rules, which causes disorder to spread.

  14. Depression - resources

    Science.gov (United States)

    Resources - depression ... Depression is a medical condition. If you think you may be depressed, see a health care provider. ... following organizations are good sources of information on depression : American Psychological Association -- www.apa.org/topics/depress/ ...

  15. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  16. Higher Order Spreading Models

    CERN Document Server

    Argyros, S A; Tyros, K

    2012-01-01

    We introduce the higher order spreading models associated to a Banach space $X$. Their definition is based on $\\ff$-sequences $(x_s)_{s\\in\\ff}$ with $\\ff$ a regular thin family and the plegma families. We show that the higher order spreading models of a Banach space $X$ form an increasing transfinite hierarchy $(\\mathcal{SM}_\\xi(X))_{\\xi<\\omega_1}$. Each $\\mathcal{SM}_\\xi (X)$ contains all spreading models generated by $\\ff$-sequences $(x_s)_{s\\in\\ff}$ with order of $\\ff$ equal to $\\xi$. We also provide a study of the fundamental properties of the hierarchy.

  17. Motor cortical organization in an adult with hemimegalencephaly and late onset epilepsy.

    Science.gov (United States)

    Civardi, Carlo; Vicentini, Roberta; Collini, Alessandra; Boccagni, Cristina; Cantello, Roberto; Monaco, Francesco

    2009-08-28

    Hemimegalencephaly is a rare brain malformation whose physiology is largely obscure. In a single patient, we studied motor cortex using several transcranial magnetic stimulation variables testing cortical excitability, and mapping motor area. The megalencephalic hemisphere showed an enlargement of cortical motor map with abnormal axonal orientation and an excess spread of corticospinal excitation, associated with multiple defects of cortical inhibition. TMS gave new information on the anatomic/functional features and epileptogenesis in this complex and physiologically obscure syndrome.

  18. Evolution of cortical neurogenesis.

    Science.gov (United States)

    Abdel-Mannan, Omar; Cheung, Amanda F P; Molnár, Zoltán

    2008-03-18

    The neurons of the mammalian neocortex are organised into six layers. By contrast, the reptilian and avian dorsal cortices only have three layers which are thought to be equivalent to layers I, V and VI of mammals. Increased repertoire of mammalian higher cognitive functions is likely a result of an expanded cortical surface area. The majority of cortical cell proliferation in mammals occurs in the ventricular zone (VZ) and subventricular zone (SVZ), with a small number of scattered divisions outside the germinal zone. Comparative developmental studies suggest that the appearance of SVZ coincides with the laminar expansion of the cortex to six layers, as well as the tangential expansion of the cortical sheet seen within mammals. In spite of great variation and further compartmentalisation in the mitotic compartments, the number of neurons in an arbitrary cortical column appears to be remarkably constant within mammals. The current challenge is to understand how the emergence and elaboration of the SVZ has contributed to increased cortical cell diversity, tangential expansion and gyrus formation of the mammalian neocortex. This review discusses neurogenic processes that are believed to underlie these major changes in cortical dimensions in vertebrates.

  19. Postpartum depression

    Science.gov (United States)

    Depression - postpartum; Postnatal depression; Postpartum psychological reactions ... behavioral therapy (CBT) and interpersonal therapy (IPT) are types of talk therapy that often help postpartum depression. ...

  20. Cortical Lewy Body Dementia

    Directory of Open Access Journals (Sweden)

    W. R. G. Gibb

    1990-01-01

    Full Text Available In cortical Lewy body dementia the distribution of Lewy bodies in the nervous system follows that of Parkinson's disease, except for their greater profusion in the cerebral cortex. The cortical tangles and plaques of Alzheimer pathology are often present, the likely explanation being that Alzheimer pathology provokes dementia in many patients. Pure cortical Lewy body dementia without Alzheimer pathology is uncommon. The age of onset reflects that of Parkinson's disease, and clinical features, though not diagnostic, include aphasias, apraxias, agnosias, paranoid delusions and visual hallucinations. Parkinsonism may present before or after the dementia, and survival duration is approximately half that seen in Parkinson's disease without dementia.

  1. Focal cortical dysplasia - review.

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-04-01

    Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types

  2. Postpartum cortical blindness.

    Science.gov (United States)

    Faiz, Shakeel Ahmed

    2008-09-01

    A 30-years-old third gravida with previous normal pregnancies and an unremarkable prenatal course had an emergency lower segment caesarean section at a periphery hospital for failure of labour to progress. She developed bilateral cortical blindness immediately after recovery from anesthesia due to cerebral angiopathy shown by CT and MR scan as cortical infarct cerebral angiopathy, which is a rare complication of a normal pregnancy.

  3. A revised view of sensory cortical parcellation

    Science.gov (United States)

    Wallace, Mark T.; Ramachandran, Ramnarayan; Stein, Barry E.

    2004-01-01

    Traditional cortical parcellation schemes have emphasized the presence of sharply defined visual, auditory, and somatosensory domains populated exclusively by modality-specific neurons (i.e., neurons responsive to sensory stimuli from a single sensory modality). However, the modality-exclusivity of this scheme has recently been challenged. Observations in a variety of species suggest that each of these domains is subject to influences from other senses. Using the cerebral cortex of the rat as a model, the present study systematically examined the capability of individual neurons in visual, auditory, and somatosensory cortex to be activated by stimuli from other senses. Within the major modality-specific domains, the incidence of inappropriate (i.e., nonmatching) and/or multisensory neurons was very low. However, at the borders between each of these domains a concentration of multisensory neurons was found whose modality profile matched the representations in neighboring cortices and that were able to integrate their cross-modal inputs to give rise to enhanced and/or depressed responses. The results of these studies are consistent with some features of both the traditional and challenging views of cortical organization, and they suggest a parcellation scheme in which modality-specific cortical domains are separated from one another by transitional multisensory zones. PMID:14766982

  4. Spread codes and spread decoding in network coding

    OpenAIRE

    Manganiello, F; Gorla, E.; Rosenthal, J.

    2008-01-01

    In this paper we introduce the class of spread codes for the use in random network coding. Spread codes are based on the construction of spreads in finite projective geometry. The major contribution of the paper is an efficient decoding algorithm of spread codes up to half the minimum distance.

  5. ENDOMETRIOSIS WITH LYMPHATIC SPREAD

    Directory of Open Access Journals (Sweden)

    Narmadha

    2014-10-01

    Full Text Available Pelvic endometriosis is a common gynaecologic problem. But the histogenesis of endometriosis was not so clear. Various theories have been proposed by Pathologist in the past. Here we present a case of endometriosis of fallopian tube by lymphatic spread which has been proved histopathologically

  6. Spreading of miscible liquids

    Science.gov (United States)

    Walls, Daniel J.; Haward, Simon J.; Shen, Amy Q.; Fuller, Gerald G.

    2016-05-01

    Miscible liquids commonly contact one another in natural and technological situations, often in the proximity of a solid substrate. In the scenario where a drop of one liquid finds itself on a solid surface and immersed within a second, miscible liquid, it will spread spontaneously across the surface. We show experimental findings of the spreading of sessile drops in miscible environments that have distinctly different shape evolution and power-law dynamics from sessile drops that spread in immiscible environments, which have been reported previously. We develop a characteristic time to scale radial data of the spreading sessile drops based on a drainage flow due to gravity. This time scale is effective for a homologous subset of the liquids studied. However, it has limitations when applied to significantly chemically different, yet miscible, liquid pairings; we postulate that the surface energies between each liquid and the solid surface becomes important for this other subset of the liquids studied. Initial experiments performed with pendant drops in miscible environments support the drainage flow observed in the sessile drop systems.

  7. Virus spread in networks

    NARCIS (Netherlands)

    Mieghem, P. van; Omic, J.; Kooij, R.E.

    2009-01-01

    The influence of the network characteristics on the virus spread is analyzed in a new-the N-intertwined Markov chain-model, whose only approximation lies in the application of mean field theory. The mean field approximation is quantified in detail. The N-intertwined model has been compared with the

  8. Spreading of healthy mood in adolescent social networks.

    Science.gov (United States)

    Hill, E M; Griffiths, F E; House, T

    2015-08-22

    Depression is a major public health concern worldwide. There is evidence that social support and befriending influence mental health, and an improved understanding of the social processes that drive depression has the potential to bring significant public health benefits. We investigate transmission of mood on a social network of adolescents, allowing flexibility in our model by making no prior assumption as to whether it is low mood or healthy mood that spreads. Here, we show that while depression does not spread, healthy mood among friends is associated with significantly reduced risk of developing and increased chance of recovering from depression. We found that this spreading of healthy mood can be captured using a non-linear complex contagion model. Having sufficient friends with healthy mood can halve the probability of developing, or double the probability of recovering from, depression over a 6-12-month period on an adolescent social network. Our results suggest that promotion of friendship between adolescents can reduce both incidence and prevalence of depression.

  9. Optimizing Hybrid Spreading in Metapopulations

    CERN Document Server

    Zhang, Changwang; Cox, Ingemar J; Chain, Benjamin M

    2014-01-01

    Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by \\textit{local spreading}, where infected nodes can only infect a limited set of direct target nodes and \\textit{global spreading}, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. In a metapopulation, made up of many weakly connected subpopulations, we show that one can calculate an optimal tradeoff between local and global spreading which will maximise the extent of the epidemic. As an example we analyse the 2008 outbreak of the Internet worm Conficker, which uses hybrid spreading to propagate through the internet. Our results suggests that the worm would have been eve...

  10. Combinatorics of spreads and parallelisms

    CERN Document Server

    Johnson, Norman

    2010-01-01

    Partitions of Vector Spaces Quasi-Subgeometry Partitions Finite Focal-SpreadsGeneralizing André SpreadsThe Going Up Construction for Focal-SpreadsSubgeometry Partitions Subgeometry and Quasi-Subgeometry Partitions Subgeometries from Focal-SpreadsExtended André SubgeometriesKantor's Flag-Transitive DesignsMaximal Additive Partial SpreadsSubplane Covered Nets and Baer Groups Partial Desarguesian t-Parallelisms Direct Products of Affine PlanesJha-Johnson SL(2,

  11. Recovery of slow potentials in AC-coupled electrocorticography: application to spreading depolarizations in rat and human cerebral cortex.

    Science.gov (United States)

    Hartings, Jed A; Watanabe, Tomas; Dreier, Jens P; Major, Sebastian; Vendelbo, Leif; Fabricius, Martin

    2009-10-01

    Cortical spreading depolarizations (spreading depressions and peri-infarct depolarizations) are a pathology intrinsic to acute brain injury, generating large negative extracellular slow potential changes (SPCs) that, lasting on the order of minutes, are studied with DC-coupled recordings in animals. The spreading SPCs of depolarization waves are observed in human cortex with AC-coupled electrocorticography (ECoG), although SPC morphology is distorted by the high-pass filter stage of the amplifiers. Here, we present a signal processing method to reverse these distortions and recover approximate full-band waveforms from AC-coupled recordings. We constructed digital filters that reproduced the phase and amplitude distortions introduced by specific AC-coupled amplifiers and, based on this characterization, derived digital inverse filters to remove these distortions from ECoG recordings. Performance of the inverse filter was validated by its ability to recover both simulated and real low-frequency input test signals. The inverse filter was then applied to AC-coupled ECoG recordings from five patients who underwent invasive monitoring after aneurysmal subarachnoid hemorrhage. For 117 SPCs, the inverse filter recovered full-band waveforms with morphologic characteristics typical of the negative DC shifts recorded in animals. Compared with those recorded in the rat cortex with the same analog and digital methods, the negative DC shifts of human depolarizations had significantly greater durations (1:47 vs. 0:45 min:sec) and peak-to-peak amplitudes (10.1 vs. 4.2 mV). The inverse filter thus permits the study of spreading depolarizations in humans, using the same assessment of full-band DC potentials as that in animals, and suggests a particular solution for recovery of biosignals recorded with frequency-limited amplifiers.

  12. Susceptibility of Primary Sensory Cortex to Spreading Depolarizations

    OpenAIRE

    Bogdanov, VB; Middleton, NA; Theriot, JJ; Parker, PD; Abdullah, OM; Ju, YS; Hartings, JA; Brennan, KC

    2016-01-01

    Spreading depolarizations (SDs) are recognized as actors in neurological disorders as diverse as migraine and traumatic brain injury (TBI). Migraine aura involves sensory percepts, suggesting that sensory cortices might be intrinsically susceptible to SDs. We used optical imaging, MRI, and field potential and potassium electrode recordings in mice and electrocorticographic recordings in humans to determine the susceptibility of different brain regions to SDs. Optical imaging experiments in mi...

  13. Quasirandom Rumor Spreading

    CERN Document Server

    Doerr, Benjamin; Sauerwald, Thomas

    2010-01-01

    We propose and analyse a quasirandom analogue of the classical push model for disseminating information in networks ("randomized rumor spreading"). In the classical model, in each round each informed vertex chooses a neighbor at random and informs it, if it was not before. It is known that this simple protocol succeeds in spreading a rumor from one vertex to all others within O(log n) rounds on complete graphs, hypercubes, random regular graphs, Erdos-Renyi random graph and Ramanujan graphs with high probability. In the quasirandom model, we assume that each vertex has a (cyclic) list of its neighbors. Once informed, it starts at a random position of the list, but from then on informs its neighbors in the order of the list. Surprisingly, irrespective of the orders of the lists, the above mentioned bounds still hold. In some cases even better bounds than for the classical model can be shown.

  14. Spread spectrum image steganography.

    Science.gov (United States)

    Marvel, L M; Boncelet, C R; Retter, C T

    1999-01-01

    In this paper, we present a new method of digital steganography, entitled spread spectrum image steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, error-control coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embedded control, and revision tracking.

  15. Cortical myoclonus and cerebellar pathology

    NARCIS (Netherlands)

    Tijssen, MAJ; Thom, M; Ellison, DW; Wilkins, P; Barnes, D; Thompson, PD; Brown, P

    2000-01-01

    Objective To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. Background: The pathologic findings in conditions associated with cortical myoclonus commonly involve

  16. Cortical Abnormalities in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-12-01

    Full Text Available Grey-matter abnormalities at the cortical surface and regional brain size were mapped by high-resolution MRI and surface-based, computational image analytical techniques in a group of 27 children and adolescents with attention deficit hyperactivity disorder (ADHD and 46 controls, matched by age and sex, at the University of California at Los Angeles.

  17. Transient cortical blindness after coronary artery angiography.

    Science.gov (United States)

    Terlecki, Michał; Wojciechowska, Wiktoria; Rajzer, Marek; Jurczyszyn, Artur; Bazan-Socha, Stanisława; Bryniarski, Leszek; Czarnecka, Danuta

    2013-01-01

    Coronary angiography is the current gold standard for the diagnosis of ischemic heart disease and therefore the prevalence of percutaneous coronary procedures such as angiography and angioplasty is high. The occurrence of cerebral complications after coronary angiography and coronary angioplasty is low and it mainly includes transient ischemic attack and stroke. The prevalence of transient cortical blindness after X-ray contrast media is low and it is usually seen after cerebral angiography. Until now only a few cases of transient cortical blindness have been described after coronary artery angiography. Regarding the spread of coronary angiography worldwide and in Poland this complication is uniquely rare. A 32-year-old man with multiple extrasystolic ventricular arrhythmia suggesting Brugada syndrome diagnosis according to morphology of the left bundle branch block and with decreased left ventricular ejection fraction was admitted to the First Department of Cardiology and Hypertension, Medical College of the Jagiellonian University in Krakow. Coronary angiography was performed in order to exclude ischemic etiology of the observed abnormalities. No arteriosclerotic lesions were found in coronary arteries. Transient cortical blindness was observed directly after angiography which may have been caused by the neurotoxic effect of the used X-ray contrast medium. In ophthalmologic and neurologic examination as well as in the cerebral computed tomography scan no pathologies were found. Visual impairment disappeared totally within several hours.

  18. Functional rehabilitation of partial cortical blindness?

    Science.gov (United States)

    Stoerig, Petra

    2008-01-01

    The current doctrine regards fields of partial cortical blindness as permanent once a temporally restricted window for spontaneous recovery has passed. Accordingly, neuropsychological rehabilitation mainly applies compensatory procedures that train patients to make better use of their sighted field. The more ambitious goal of functional recovery depends on the survival of pathways that continue to transmit retinal information from the blind field. Although wide-spread antero- and retrograde degeneration follows lesions that destroy or denervate the primary visual cortex and cause partial cortical blindness, several retinofugal pathways survive in cats, monkeys, and humans. In all three species, they subserve a variety of visual functions which develop and improve with practice. Post lesion plasticity is greater when the lesion occurs early in life, but changes in behavioural performance and brain responses have also been demonstrated in late lesion subjects. Although the extent of functional improvement is variable, and the most effective approaches still need to be established across cohorts, the evidence for perceptual learning in fields of cortical blindness indicates that the visual processes mediated by the surviving parts of the visual system can be harnessed to improve functional outcome.

  19. Postpartum Depression

    Science.gov (United States)

    ... starts about 1–3 weeks after childbirth. What causes postpartum depression? Postpartum depression probably is caused by a combination ... better. Can antidepressants cause side effects? Antidepressants can ... If your depression worsens soon after starting medication or if you ...

  20. Caregiver Depression

    Science.gov (United States)

    ... will not sell or share your name. Caregiver Depression Tweet Bookmark this page | Email | Print Many caregivers ... depression See your doctor Treatment Coping Symptoms of depression Caregiving is hard — and can lead to feelings ...

  1. Estimation of wave directional spreading

    Digital Repository Service at National Institute of Oceanography (India)

    Deo, M.C.; Gondane, D.S.; SanilKumar, V.

    One of the useful measures of waves directional spreading at a given location is the directional spreading parameter. This paper presents a new approach to arrive at its characteristic value using the computational technique of Artificial Neural...

  2. Hybrid spread spectrum radio system

    Science.gov (United States)

    Smith, Stephen F [London, TN; Dress, William B [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  3. Purely Cortical Anaplastic Ependymoma

    Directory of Open Access Journals (Sweden)

    Flávio Ramalho Romero

    2012-01-01

    Full Text Available Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma.

  4. Fundamentals of spread spectrum modulation

    CERN Document Server

    Ziemer, Rodger E

    2007-01-01

    This lecture covers the fundamentals of spread spectrum modulation, which can be defined as any modulation technique that requires a transmission bandwidth much greater than the modulating signal bandwidth, independently of the bandwidth of the modulating signal. After reviewing basic digital modulation techniques, the principal forms of spread spectrum modulation are described. One of the most important components of a spread spectrum system is the spreading code, and several types and their characteristics are described. The most essential operation required at the receiver in a spread spect

  5. [Posterior cortical atrophy].

    Science.gov (United States)

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  6. Rifts in spreading wax layers

    CERN Document Server

    Ragnarsson, R; Santangelo, C D; Bodenschatz, E; Ragnarsson, Rolf; Ford, J Lewis; Santangelo, Christian D; Bodenschatz, Eberhard

    1995-01-01

    We report experimental results on the rift formation between two freezing wax plates. The plates were pulled apart with constant velocity, while floating on the melt, in a way akin to the tectonic plates of the earth's crust. At slow spreading rates, a rift, initially perpendicular to the spreading direction, was found to be stable, while above a critical spreading rate a "spiky" rift with fracture zones almost parallel to the spreading direction developed. At yet higher spreading rates a second transition from the spiky rift to a zig-zag pattern occurred. In this regime the rift can be characterized by a single angle which was found to be dependent on the spreading rate. We show that the oblique spreading angles agree with a simple geometrical model. The coarsening of the zig-zag pattern over time and the three-dimensional structure of the solidified crust are also discussed.

  7. Analysis of the presence or absence of atrophy of the subgenual and subcallosal cingulate cortices using voxel-based morphometry on MRI is useful to select prescriptions for patients with depressive symptoms

    Directory of Open Access Journals (Sweden)

    Niida A

    2014-12-01

    Full Text Available Akira Niida,1 Richi Niida,2 Hiroshi Matsuda,3 Makoto Motomura,4 Akihiko Uechi5 1Department of Radiology, Nanbu Hospital, Itoman City, Okinawa, Japan; 2Department of Psychiatry, Nanto Clinic, Urasoe City, Okinawa, Japan; 3Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Kodaira City, Tokyo, Japan; 4Department of Human Sciences, University of the Ryukyus, Nakagami County, Okinawa, Japan; 5Cognitive Neuroscience Research Project, Kansai Gaidai University, Hirakata City, Osaka, Japan Objective: We objectively evaluated the presence or absence of atrophy of the subgenual anterior cingulate cortex (sgACC and the subcallosal anterior cingulate cortex (scACC, using new voxel-based morphometry (VBM software employing Statistical Parametric Mapping software v8 and diffeomorphic anatomic registration through an exponentiated lie algebra. We prepared a database covering young-mature adulthood and investigated the clinical usefulness of the evaluation. Subjects and methods: One hundred seven patients with major depressive disorder (MDD, 74 patients with bipolar disorder (BD, and 240 healthy control subjects underwent 1.5T magnetic resonance imaging scanning. Using new VBM software and databases covering young-mature adults and the elderly, target volumes of interest were set in the sgACC and scACC, four indicators (severity, extent, ratio, and whole-brain extent were determined, and the presence or absence of atrophy of the sgACC and scACC was evaluated on the basis of the indicators. In addition, the relationships between the presence or absence of atrophy of the sgACC and scACC and performance of diagnosing MDD and BD and therapeutic drugs were investigated. Results: It was clarified that the disease is likely to be MDD when atrophy is detected in the sgACC, and likely to be BD when no atrophy is detected in the sgACC but is detected in the scACC. Regarding the relationship with therapeutic drugs, it was clarified that, when

  8. Competing spreading processes and immunization in multiplex networks

    CERN Document Server

    Gao, Bo

    2016-01-01

    Epidemic spreading on physical contact network will naturally introduce the human awareness information diffusion on virtual contact network, and the awareness diffusion will in turn depress the epidemic spreading, thus forming the competing spreading processes of epidemic and awareness in a multiplex networks. In this paper, we study the competing dynamics of epidemic and awareness, both of which follow the SIR process, in a two-layer networks based on microscopic Markov chain approach and numerical simulations. We find that strong capacities of awareness diffusion and self-protection of individuals could lead to a much higher epidemic threshold and a smaller outbreak size. However, the self-awareness of individuals has no obvious effect on the epidemic threshold and outbreak size. In addition, the immunization of the physical contact network under the interplay between of epidemic and awareness spreading is also investigated. The targeted immunization is found performs much better than random immunization, ...

  9. Maximizing Sensory Dynamic Range by Tuning the Cortical State to Criticality.

    Directory of Open Access Journals (Sweden)

    Shree Hari Gautam

    2015-12-01

    Full Text Available Modulation of interactions among neurons can manifest as dramatic changes in the state of population dynamics in cerebral cortex. How such transitions in cortical state impact the information processing performed by cortical circuits is not clear. Here we performed experiments and computational modeling to determine how somatosensory dynamic range depends on cortical state. We used microelectrode arrays to record ongoing and whisker stimulus-evoked population spiking activity in somatosensory cortex of urethane anesthetized rats. We observed a continuum of different cortical states; at one extreme population activity exhibited small scale variability and was weakly correlated, the other extreme had large scale fluctuations and strong correlations. In experiments, shifts along the continuum often occurred naturally, without direct manipulation. In addition, in both the experiment and the model we directly tuned the cortical state by manipulating inhibitory synaptic interactions. Our principal finding was that somatosensory dynamic range was maximized in a specific cortical state, called criticality, near the tipping point midway between the ends of the continuum. The optimal cortical state was uniquely characterized by scale-free ongoing population dynamics and moderate correlations, in line with theoretical predictions about criticality. However, to reproduce our experimental findings, we found that existing theory required modifications which account for activity-dependent depression. In conclusion, our experiments indicate that in vivo sensory dynamic range is maximized near criticality and our model revealed an unanticipated role for activity-dependent depression in this basic principle of cortical function.

  10. Maximizing Sensory Dynamic Range by Tuning the Cortical State to Criticality

    Science.gov (United States)

    Gautam, Shree Hari; Hoang, Thanh T.; McClanahan, Kylie; Grady, Stephen K.; Shew, Woodrow L.

    2015-01-01

    Modulation of interactions among neurons can manifest as dramatic changes in the state of population dynamics in cerebral cortex. How such transitions in cortical state impact the information processing performed by cortical circuits is not clear. Here we performed experiments and computational modeling to determine how somatosensory dynamic range depends on cortical state. We used microelectrode arrays to record ongoing and whisker stimulus-evoked population spiking activity in somatosensory cortex of urethane anesthetized rats. We observed a continuum of different cortical states; at one extreme population activity exhibited small scale variability and was weakly correlated, the other extreme had large scale fluctuations and strong correlations. In experiments, shifts along the continuum often occurred naturally, without direct manipulation. In addition, in both the experiment and the model we directly tuned the cortical state by manipulating inhibitory synaptic interactions. Our principal finding was that somatosensory dynamic range was maximized in a specific cortical state, called criticality, near the tipping point midway between the ends of the continuum. The optimal cortical state was uniquely characterized by scale-free ongoing population dynamics and moderate correlations, in line with theoretical predictions about criticality. However, to reproduce our experimental findings, we found that existing theory required modifications which account for activity-dependent depression. In conclusion, our experiments indicate that in vivo sensory dynamic range is maximized near criticality and our model revealed an unanticipated role for activity-dependent depression in this basic principle of cortical function. PMID:26623645

  11. Auditory Stimulation Dishabituates Olfactory Responses via Noradrenergic Cortical Modulation

    Directory of Open Access Journals (Sweden)

    Jonathan J. Smith

    2009-01-01

    Full Text Available Dishabituation is a return of a habituated response if context or contingency changes. In the mammalian olfactory system, metabotropic glutamate receptor mediated synaptic depression of cortical afferents underlies short-term habituation to odors. It was hypothesized that a known antagonistic interaction between these receptors and norepinephrine ß-receptors provides a mechanism for dishabituation. The results demonstrate that a 108 dB siren induces a two-fold increase in norepinephrine content in the piriform cortex. The same auditory stimulus induces dishabituation of odor-evoked heart rate orienting bradycardia responses in awake rats. Finally, blockade of piriform cortical norepinephrine ß-receptors with bilateral intracortical infusions of propranolol (100 μM disrupts auditory-induced dishabituation of odor-evoked bradycardia responses. These results provide a cortical mechanism for a return of habituated sensory responses following a cross-modal alerting stimulus.

  12. [The emotional status and indices of cortical neurodynamics in hypertension patients].

    Science.gov (United States)

    Shpak, L V; Kolbasnikov, S V

    1995-01-01

    At early stages of essential hypertension (EH) clinical psychological examinations of 96 EH patients revealed predominance of anxiety-hypochondriac responses controlled by will. Changes in cortical neurodynamics were evident from a decline in attention concentration. At EH stage II persistent hypertension and prolonged psychogenias gave rise to psychic disadaptation occurring as anxious-depressive conditions. Damage to cortical neurodynamics brought about mnestic and thinking disorders.

  13. [Recited depression].

    Science.gov (United States)

    Barucci, M; Cossio, M

    1984-01-01

    Several subjects who tell their depression and play a part of it in front of the doctor without being really depressed are reported. Some of them try to hide the symptoms (irritability or erethism, ceremonials of obsessive neurosis, shunning of phobia) which, in their opinion, might be detrimental to their reputation. Others neglect to describe some of the symptoms of their polymorphous clinical picture only underlining the depressive signs. Some others play a part of depression because they have believed to recognize themselves in persons presented by mass media, because it seems to them a duty to show an adequate depression in case of mournful event, or because they "convert" their problem into a depression. Some others use depression as a blackmail, or to obtain an advantage from doctor's conviction about their illness. The reason for the high frequency of similar cases in the present time are examined: the scientific divulgation and the acceptance of depression by the modern society are among the most important ones. The peculiar semantic vicissitudes of the word depression are also reviewed. A widening of the boundaries of depression has contributed to an increase in the number of the cases. Finally, in addition to patients who are depressed without being aware of it, the authors focus the inverse possibility: patients who believed or try to make their doctor believe (playing the part of depression in front of them) that they are depressed.

  14. Osteocyte lacunar properties in rat cortical bone

    DEFF Research Database (Denmark)

    Bach-Gansmo, Fiona Linnea; Weaver, James C.; Jensen, Mads Hartmann

    2015-01-01

    to osteocyte function, osteocyte lacunar properties such as volume, shape, orientation, and density are now frequently reported in studies investigating osteocyte activity. Despite this increasing interest in lacunar morphometrics, many studies show a large spread in such values, suggesting a large inter......-species but also inter-site variation in lacunar properties. Here, osteocyte lacunae in rat cortical bone have been studied using synchrotron radiation micro computed tomography (SR μCT) and backscattered electron (BE) microscopy. Quantitative lacunar geometric characteristics are reported based on the synchrotron...... radiation data, differentiating between circumferential lamellar bone and a central, more disordered bone type. From these studies, no significant differences were found in lacunar volumes between lamellar and central bone, whereas significant differences in lacunar orientation, shape and density values...

  15. Atypical Depression

    Science.gov (United States)

    ... satisfaction and control in your life Help ease depression symptoms such as hopelessness and anger As part of your treatment, it's important to also address other conditions that often accompany atypical depression, in particular anxiety and drug or alcohol use, ...

  16. Teen Depression

    Science.gov (United States)

    ... Depression is a real, treatable brain illness, or health problem. Depression can be caused by big transitions in life, stress, or changes in your body’s chemicals that affect your thoughts and moods. Even if you feel ...

  17. Postpartum Depression

    Science.gov (United States)

    ... do not need treatment. The symptoms of postpartum depression last longer and are more severe. You may ... treatment right away, often in the hospital. Postpartum depression can begin anytime within the first year after ...

  18. Depression Treatment

    Science.gov (United States)

    ... 3286 After hours (404) 639-2888 Contact Media Depression Treatment Recommend on Facebook Tweet Share Compartir On ... How Do I Know if I Am Experiencing Depression? The following questions may help you determine if ...

  19. Depression Screening

    Science.gov (United States)

    ... Centers Diseases + Condition Centers Mental Health Medical Library Depression Screening (PHQ-9) - Instructions The following questions are ... this tool, there is also text-only version . Depression Screening - Manual Instructions The following questions are a ...

  20. Heat transfer and fire spread

    Science.gov (United States)

    Hal E. Anderson

    1969-01-01

    Experimental testing of a mathematical model showed that radiant heat transfer accounted for no more than 40% of total heat flux required to maintain rate of spread. A reasonable prediction of spread was possible by assuming a horizontal convective heat transfer coefficient when certain fuel and flame characteristics were known. Fuel particle size had a linear relation...

  1. Drop spreading with random viscosity

    CERN Document Server

    Xu, Feng

    2016-01-01

    We examine theoretically the spreading of a viscous liquid drop over a thin film of uniform thickness, assuming the liquid's viscosity is regulated by the concentration of a solute that is carried passively by the spreading flow. The solute is assumed to be initially heterogeneous, having a spatial distribution with prescribed statistical features. To examine how this variability influences the drop's motion, we investigate spreading in a planar geometry using lubrication theory, combining numerical simulations with asymptotic analysis. We assume diffusion is sufficient to suppress solute concentration gradients across but not along the film. The solute field beneath the bulk of the drop is stretched by the spreading flow, such that the initial solute concentration immediately behind the drop's effective contact lines has a long-lived influence on the spreading rate. Over long periods, solute swept up from the precursor film accumulates in a short region behind the contact line, allowing patches of elevated v...

  2. Sinking, wedging, spreading - viscous spreading on a layer of fluid

    Science.gov (United States)

    Bergemann, Nico; Juel, Anne; Heil, Matthias

    2016-11-01

    We study the axisymmetric spreading of a sessile drop on a pre-existing layer of the same fluid in a regime where the drop is sufficiently large so that the spreading is driven by gravity while capillary and inertial effects are negligible. Experiments performed with 5 ml drops and layer thicknesses in the range 0.1 mm drop evolves as R tn , where the spreading exponent n increases with the layer thickness h. Numerical simulations, based on the axisymmetric free-surface Navier-Stokes equations, reveal three distinct spreading regimes depending on the layer thickness. For thick layers the drop sinks into the layer, accompanied by significant flow in the layer. By contrast, for thin layers the layer ahead of the propagating front is at rest and the spreading behaviour resembles that of a gravity-driven drop spreading on a dry substrate. In the intermediate regime the spreading is characterised by an advancing wedge, which is sustained by fluid flow from the drop into the layer.

  3. Evaluating mandibular cortical index quantitatively.

    Science.gov (United States)

    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  4. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  5. Cortical and spinal assessment

    DEFF Research Database (Denmark)

    Fischer, I W; Gram, Mikkel; Hansen, T M

    2017-01-01

    BACKGROUND: Standardized objective methods to assess the analgesic effects of opioids, enable identification of underlying mechanisms of drug actions in the central nervous system. Opioids may exert their effect on both cortical and spinal levels. In this study actions of morphine at both levels...... subjects was included in the data analysis. There was no change in the activity in resting EEG (P>0.05) after morphine administration as compared to placebo. During cold pressor stimulation, morphine significantly lowered the relative activity in the delta (1-4Hz) band (P=0.03) and increased the activity...... morphine administration (P>0.05). CONCLUSIONS: Cold pressor EEG and the nociceptive reflex were more sensitive to morphine analgesia than resting EEG and can be used as standardized objective methods to assess opioid effects. However, no correlation between the analgesic effect of morphine on the spinal...

  6. Hiperostosis cortical infantil

    OpenAIRE

    Salvador Javier Santos Medina; Orelvis Pérez Duerto

    2015-01-01

    La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco mes...

  7. Progressive posterior cortical dysfunction

    Directory of Open Access Journals (Sweden)

    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  8. Cortical plasticity and rehabilitation.

    Science.gov (United States)

    Moucha, Raluca; Kilgard, Michael P

    2006-01-01

    The brain is constantly adapting to environmental and endogenous changes (including injury) that occur at every stage of life. The mechanisms that regulate neural plasticity have been refined over millions of years. Motivation and sensory experience directly shape the rewiring that makes learning and neurological recovery possible. Guiding neural reorganization in a manner that facilitates recovery of function is a primary goal of neurological rehabilitation. As the rules that govern neural plasticity become better understood, it will be possible to manipulate the sensory and motor experience of patients to induce specific forms of plasticity. This review summarizes our current knowledge regarding factors that regulate cortical plasticity, illustrates specific forms of reorganization induced by control of each factor, and suggests how to exploit these factors for clinical benefit.

  9. Spreading convulsions, spreading depolarization and epileptogenesis in human cerebral cortex

    DEFF Research Database (Denmark)

    Dreier, Jens P; Major, Sebastian; Pannek, Heinz-Wolfgang

    2012-01-01

    Spreading depolarization of cells in cerebral grey matter is characterized by massive ion translocation, neuronal swelling and large changes in direct current-coupled voltage recording. The near-complete sustained depolarization above the inactivation threshold for action potential generating...

  10. Spreading depolarizations in patients with spontaneous intracerebral hemorrhage

    DEFF Research Database (Denmark)

    Helbok, Raimund; Schiefecker, Alois Josef; Friberg, Christian;

    2017-01-01

    Pathophysiologic mechanisms of secondary brain injury after intracerebral hemorrhage and in particular mechanisms of perihematomal-edema progression remain incompletely understood. Recently, the role of spreading depolarizations in secondary brain injury was established in ischemic stroke......, subarachnoid hemorrhage and traumatic brain injury patients. Its role in intracerebral hemorrhage patients and in particular the association with perihematomal-edema is not known. A total of 27 comatose intracerebral hemorrhage patients in whom hematoma evacuation and subdural electrocorticography...... patients (67%), a total of 650 spreading depolarizations were observed. Spreading depolarizations were more common in the initial days with a peak incidence on day 2. Median electrocorticography depression time was longer than previously reported (14.7 min, IQR, 9-22 min). Postoperative perihematomal-edema...

  11. Delayed ischaemic neurological deficits after subarachnoid haemorrhage are associated with clusters of spreading depolarizations.

    Science.gov (United States)

    Dreier, Jens P; Woitzik, Johannes; Fabricius, Martin; Bhatia, Robin; Major, Sebastian; Drenckhahn, Chistoph; Lehmann, Thomas-Nicolas; Sarrafzadeh, Asita; Willumsen, Lisette; Hartings, Jed A; Sakowitz, Oliver W; Seemann, Jörg H; Thieme, Anja; Lauritzen, Martin; Strong, Anthony J

    2006-12-01

    Progressive ischaemic damage in animals is associated with spreading mass depolarizations of neurons and astrocytes, detected as spreading negative slow voltage variations. Speculation on whether spreading depolarizations occur in human ischaemic stroke has continued for the past 60 years. Therefore, we performed a prospective multicentre study assessing incidence and timing of spreading depolarizations and delayed ischaemic neurological deficit (DIND) in patients with major subarachnoid haemorrhage (SAH) requiring aneurysm surgery. Spreading depolarizations were recorded by electrocorticography with a subdural electrode strip placed on cerebral cortex for up to 10 days. A total of 2110 h recording time was analysed. The clinical state was monitored every 6 h. Delayed infarcts after SAH were verified by serial CT scans and/or MRI. Electrocorticography revealed 298 spreading depolarizations in 13 of the 18 patients (72%). A clinical DIND was observed in seven patients 7.8 days (7.3, 8.2) after SAH. DIND was time-locked to a sequence of recurrent spreading depolarizations in every single case (positive and negative predictive values: 86 and 100%, respectively). In four patients delayed infarcts developed in the recording area. As in the ischaemic penumbra of animals, delayed infarction was preceded by progressive prolongation of the electrocorticographic depression periods associated with spreading depolarizations to >60 min in each case. This study demonstrates that spreading depolarizations have a high incidence in major SAH and occur in ischaemic stroke. Repeated spreading depolarizations with prolonged depression periods are an early indicator of delayed ischaemic brain damage after SAH. In view of experimental evidence and the present clinical results, we suggest that spreading depolarizations with prolonged depressions are a promising target for treatment development in SAH and ischaemic stroke.

  12. Models of cortical malformation--Chemical and physical.

    Science.gov (United States)

    Luhmann, Heiko J

    2016-02-15

    Pharmaco-resistant epilepsies, and also some neuropsychiatric disorders, are often associated with malformations in hippocampal and neocortical structures. The mechanisms leading to these cortical malformations causing an imbalance between the excitatory and inhibitory system are largely unknown. Animal models using chemical or physical manipulations reproduce different human pathologies by interfering with cell generation and neuronal migration. The model of in utero injection of methylazoxymethanol (MAM) acetate mimics periventricular nodular heterotopia. The freeze lesion model reproduces (poly)microgyria, focal heterotopia and schizencephaly. The in utero irradiation model causes microgyria and heterotopia. Intraperitoneal injections of carmustine 1-3-bis-chloroethyl-nitrosurea (BCNU) to pregnant rats produces laminar disorganization, heterotopias and cytomegalic neurons. The ibotenic acid model induces focal cortical malformations, which resemble human microgyria and ulegyria. Cortical dysplasia can be also observed following prenatal exposure to ethanol, cocaine or antiepileptic drugs. All these models of cortical malformations are characterized by a pronounced hyperexcitability, few of them also produce spontaneous epileptic seizures. This dysfunction results from an impairment in GABAergic inhibition and/or an increase in glutamatergic synaptic transmission. The cortical region initiating or contributing to this hyperexcitability may not necessarily correspond to the site of the focal malformation. In some models wide-spread molecular and functional changes can be observed in remote regions of the brain, where they cause pathophysiological activities. This paper gives an overview on different animal models of cortical malformations, which are mostly used in rodents and which mimic the pathology and to some extent the pathophysiology of neuronal migration disorders associated with epilepsy in humans.

  13. Spreading the Bible in China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    According to records of the Bible Society in China, more than 300 million copies of the Bible in Chinese have been published and distributed since 1823. The spread of the Bible in China has gone through five stages.

  14. Spread effects - methodology; Spredningseffekter - metodegrunnlag

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    Diffusion of technology, environmental effects and rebound effects are the principal effects from the funding of renewable energy and energy economising. It is difficult to estimate the impact of the spread effects both prior to the measures are implemented and after the measures are carried out. Statistical methods can be used to estimate the spread effects, but they are insecure and always need to be complemented with qualitative and subjective evaluations. It is more adequate to evaluate potential spread effects from market and market data surveillance for a selection of technologies and parties. Based on this information qualitative indicators for spread effects can be constructed and used both ex ante and ex post (ml)

  15. Roles of Ties in Spreading

    CERN Document Server

    Cui, Ai-Xiang; Zhou, Tao

    2012-01-01

    Background: Controlling global epidemics in the real world and accelerating information propagation in the artificial world are of great significance, which have activated an upsurge in the studies on networked spreading dynamics. Lots of efforts have been made to understand the impacts of macroscopic statistics (e.g., degree distribution and average distance) and mesoscopic structures (e.g., communities and rich clubs) on spreading processes while the microscopic elements are less concerned. In particular, roles of ties are not yet clear to the academic community. Methodology/Principle Findings: Every edges is stamped by its strength that is defined solely based on the local topology. According to a weighted susceptible-infected-susceptible model, the steady-state infected density and spreading speed are respectively optimized by adjusting the relationship between edge's strength and spreading ability. Experiments on six real networks show that the infected density is increased when strong ties are favored i...

  16. Epidemic spreading in complex networks

    Institute of Scientific and Technical Information of China (English)

    Jie ZHOU; Zong-hua LIU

    2008-01-01

    The study of epidemic spreading in complex networks is currently a hot topic and a large body of results have been achieved.In this paper,we briefly review our contributions to this field,which includes the underlying mechanism of rumor propagation,the epidemic spreading in community networks,the influence of varying topology,and the influence of mobility of agents.Also,some future directions are pointed out.

  17. High levels of neuroticism are associated with decreased cortical folding of the dorsolateral prefrontal cortex.

    Science.gov (United States)

    Christoph Schultz, C; Warziniak, Heide; Koch, Kathrin; Schachtzabel, Claudia; Güllmar, Daniel; Reichenbach, Jürgen R; Schlösser, Ralf G; Sauer, Heinrich; Wagner, Gerd

    2017-04-06

    The personality trait neuroticism has been identified as a vulnerability factor for common psychiatric diseases and defining potential neuroanatomical markers for early recognition and prevention strategies is mandatory. Because both personality traits and cortical folding patterns are early imprinted and timely stable there is reason to hypothesize an association between neuroticism and cortical folding. Thus, to identify a putative linkage, we tested whether the degree of neuroticism is associated with local cortical folding in a sample of 109 healthy individuals using a surface-based MRI approach. Based on previous findings we additionally tested for a potential association with cortical thickness. We found a highly significant negative correlation between the degree of neuroticism and local cortical folding of the left dorsolateral prefrontal cortex (DLPFC), i.e., high levels of neuroticism were associated with low cortical folding of the left DLPFC. No association was found with cortical thickness. The present study is the first to describe a linkage between the extent of local cortical folding and the individual degree of neuroticism in healthy subjects. Because neuroticism is a vulnerability factor for common psychiatric diseases such as depression our finding indicates that alterations of DLPFC might constitute a neurobiological marker elevating risk for psychiatric burden.

  18. Identification of a circuit-based endophenotype for familial depression.

    Science.gov (United States)

    Dubin, Marc J; Dubin, Marc; Weissman, Myrna M; Weissman, Myrna; Xu, Dongrong; Bansal, Ravi; Hao, Xuejun; Liu, Jun; Warner, Virginia; Peterson, Bradley S; Peterson, Bradley

    2012-03-31

    Frontal and parietal lesions may cause depression, and cortical thinning of the right frontal and parietal lobes has been shown to be a marker of risk for familial major depression. We studied biological offspring within a three-generation cohort, in which risk was defined by the depression status of the first generation, to identify regional volume differences associated with risk for depression throughout the cerebrum. We found reduced frontal and parietal white matter volumes in the high-risk group, including in persons without any personal history of depression, suggesting that hypoplasia of frontal and parietal white matter is an endophenotype for familial depression. In addition, white matter volumes in these regions correlated with current severity of symptoms of depression, inattention, and impulsivity. White matter volumes also correlated strongly with the degree of thinning in the right parietal cortex. These findings support a model of pathogenesis in which hypoplasia within a neural network for attention and emotional processing predisposes to depression.

  19. Cortical synaptic transmission in CaV2.1 knockin mice with the S218L missense mutation which causes a severe familial hemiplegic migraine syndrome in humans.

    Directory of Open Access Journals (Sweden)

    Dania eVecchia

    2015-02-01

    Full Text Available Familial hemiplegic migraine type 1 (FHM1 is caused by gain-of-function mutations in CaV2.1 (P/Q-type Ca2+ channels. Knockin (KI mice carrying the FHM1 R192Q missense mutation show enhanced cortical excitatory synaptic transmission at pyramidal cell synapses but unaltered cortical inhibitory neurotransmission at fast-spiking interneuron synapses. Enhanced cortical glutamate release was shown to cause the facilitation of cortical spreading depression (CSD in R192Q KI mice. It, however, remains unknown how other FHM1 mutations affect cortical synaptic transmission. Here, we studied neurotransmission in cortical neurons in microculture from KI mice carrying the S218L mutation, which causes a severe FHM syndrome in humans and an allele-dosage dependent facilitation of experimental CSD in KI mice, which is larger than that caused by the R192Q mutation. We show gain-of-function of excitatory neurotransmission, due to increased action-potential evoked Ca2+ influx and increased probability of glutamate release at pyramidal cell synapses, but unaltered inhibitory neurotransmission at multipolar interneuron synapses in S218L KI mice. In contrast with the larger gain-of-function of neuronal CaV2.1 current in homozygous than heterozygous S218L KI mice, the gain-of-function of evoked glutamate release, the paired-pulse ratio and the Ca2+ dependence of the EPSC were all similar in homozygous and heterozygous S218L KI mice, suggesting compensatory changes in the homozygous mice. Furthermore, we reveal a unique feature of S218L KI cortical synapses which is the presence of a fraction of mutant CaV2.1 channels being open at resting potential. Our data suggest that, while the gain-of-function of evoked glutamate release may explain the facilitation of CSD in heterozygous S218L KI mice, the further facilitation of CSD in homozygous S218L KI mice is due to other CaV2.1-dependent mechanisms, that likely include Ca2+ influx at voltages sub-threshold for action

  20. Lateral spread of orientation selectivity in V1 is controlled by intracortical cooperativity

    Directory of Open Access Journals (Sweden)

    Frédéric eChavane

    2011-02-01

    Full Text Available Neurons in the primary visual cortex receive subliminal information originating from the periphery of their receptive fields through a variety of cortical connections. In the cat primary visual cortex, long-range horizontal axons have been reported to preferentially bind to distant columns of similar orientation preferences, whereas feedback connections from higher visual areas provide a more diverse functional input. To understand the role of these lateral interactions, it is crucial to characterize their effective functional connectivity and tuning properties. However, the overall functional impact of cortical lateral connections, whatever their anatomical origin, is unknown since it has never been directly characterized. Using direct measurements of postsynaptic integration in cat areas 17/18, we performed multi-scale assessments of the functional impact of visually driven lateral networks. Voltage-sensitive dye imaging showed that local oriented stimuli evoke an orientation-selective activity that remains confined to the cortical feedforward imprint of the stimulus. Beyond a distance of one hypercolumn, the lateral spread of cortical activity gradually lost its orientation preference approximated as an exponential with a space constant of about 1mm. Intracellular recordings showed that this loss of orientation selectivity arises from the diversity of converging synaptic input patterns originating from outside the classical receptive field. In contrast, when the stimulus size was increased, we observed orientation-selective spread of activation beyond the feedforward imprint. We conclude that stimulus-induced cooperativity enhances the long-range orientation-selective spread.

  1. Focal cortical dysplasia – review

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-01-01

    Summary Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults. Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed – from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized. Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe. Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes. New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life. Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias. The most common findings on MRI imaging include: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy. However, in type I cortical dysplasia, MR imaging is often normal, and also

  2. Analysis of Cortical Flow Models In Vivo

    Science.gov (United States)

    Benink, Hélène A.; Mandato, Craig A.; Bement, William M.

    2000-01-01

    Cortical flow, the directed movement of cortical F-actin and cortical organelles, is a basic cellular motility process. Microtubules are thought to somehow direct cortical flow, but whether they do so by stimulating or inhibiting contraction of the cortical actin cytoskeleton is the subject of debate. Treatment of Xenopus oocytes with phorbol 12-myristate 13-acetate (PMA) triggers cortical flow toward the animal pole of the oocyte; this flow is suppressed by microtubules. To determine how this suppression occurs and whether it can control the direction of cortical flow, oocytes were subjected to localized manipulation of either the contractile stimulus (PMA) or microtubules. Localized PMA application resulted in redirection of cortical flow toward the site of application, as judged by movement of cortical pigment granules, cortical F-actin, and cortical myosin-2A. Such redirected flow was accelerated by microtubule depolymerization, showing that the suppression of cortical flow by microtubules is independent of the direction of flow. Direct observation of cortical F-actin by time-lapse confocal analysis in combination with photobleaching showed that cortical flow is driven by contraction of the cortical F-actin network and that microtubules suppress this contraction. The oocyte germinal vesicle serves as a microtubule organizing center in Xenopus oocytes; experimental displacement of the germinal vesicle toward the animal pole resulted in localized flow away from the animal pole. The results show that 1) cortical flow is directed toward areas of localized contraction of the cortical F-actin cytoskeleton; 2) microtubules suppress cortical flow by inhibiting contraction of the cortical F-actin cytoskeleton; and 3) localized, microtubule-dependent suppression of actomyosin-based contraction can control the direction of cortical flow. We discuss these findings in light of current models of cortical flow. PMID:10930453

  3. Hiperostosis cortical infantil

    Directory of Open Access Journals (Sweden)

    Salvador Javier Santos Medina

    2015-04-01

    Full Text Available La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco meses de edad, atendido en el Hospital Pediátrico Provincial “Mártires de Las Tunas” con este diagnóstico, quien ingresó en el servicio de miscelánea B por una celulitis facial. Presentaba aumento de volumen en la región geniana izquierda, febrícola e inapetencia. Se impuso tratamiento con cefazolina y se egresó a los siete días. Acudió nuevamente con tumefacción blanda y difusa de ambas hemicaras, irritabilidad y fiebre. Se interconsultó con cirugía maxilofacial, se indicaron estudios sanguíneos y radiológicos. Se diagnosticó como enfermedad de Caffey, basado en la edad del niño, tumefacción facial sin signos inflamatorios agudos e hiperostosis en ambas corticales mandibulares a la radiografía AP mandíbula; unido a anemia ligera, leucocitosis y eritrosedimentación acelerada. El paciente se trató sintomáticamente y con antinflamatorios no esteroideos. Esta rara entidad se debe tener presente en casos de niños y lactantes con irritabilidad y fiebre inespecífica

  4. Lack of association between prior depressive episodes and cerebral [(11)C]PiB binding

    DEFF Research Database (Denmark)

    Madsen, K; Hasselbalch, Bo Jacob; Frederiksen, K S

    2012-01-01

    Depressive symptoms are frequent in Alzheimer's disease (AD), but it is controversial whether depression is a risk factor for AD. This study measured for the first time cortical amyloid-ß (Aß) levels using [(11)C] Pittsburgh Compound B (PiB) positron emission tomography (PET) in a group of nondem......Depressive symptoms are frequent in Alzheimer's disease (AD), but it is controversial whether depression is a risk factor for AD. This study measured for the first time cortical amyloid-ß (Aß) levels using [(11)C] Pittsburgh Compound B (PiB) positron emission tomography (PET) in a group...

  5. The differential relationship between trait anxiety, depression, and resting frontal α-asymmetry.

    Science.gov (United States)

    Adolph, Dirk; Margraf, Jürgen

    2017-03-01

    Relatively larger resting right frontal cortical brain activation has been labeled as a risk factor for emotion-related disorders. In light of this framework, the present studies' aim was twofold. First, we wanted to determine whether a relationship between symptoms of anxiety and depression and frontal asymmetry does already manifest in a sample of so far healthy individuals showing a large symptom range. This could be expected if frontal asymmetry constitutes a risk factor for depression and anxiety. Second, we aimed to investigate whether symptoms of depression and anxiety are independently related to frontal asymmetry, or whether either anxiety or depression is superior in predicting the relationship with frontal asymmetry. To address these questions, trait-like resting frontal α-asymmetry by means of EEG, as well as trait anxiety and depressive symptoms by questionnaire were measured from 43 healthy students (28 female). Results indicate that higher symptom severity of depression and anxiety were both significantly correlated with relatively larger right frontal cortical activation. However, in a regression analysis, frontal asymmetry was predicted by anxiety only. Controlling for depression and mood, anxiety explained 13% of variance, while controlling for mood and anxiety, depression did explain asymmetry. In conclusion, although both anxiety and depression add to the relationship, relatively larger right frontal cortical activity might be influenced more strongly by symptoms of anxiety. Moreover, as this effect is present already in healthy individuals, the findings might further support the notion that right frontal cortical asymmetry constitutes a risk factor for anxiety or depression.

  6. Spreading dynamics in complex networks

    CERN Document Server

    Pei, Sen

    2013-01-01

    Searching for influential spreaders in complex networks is an issue of great significance for applications across various domains, ranging from the epidemic control, innovation diffusion, viral marketing, social movement to idea propagation. In this paper, we first display some of the most important theoretical models that describe spreading processes, and then discuss the problem of locating both the individual and multiple influential spreaders respectively. Recent approaches in these two topics are presented. For the identification of privileged single spreaders, we summarize several widely used centralities, such as degree, betweenness centrality, PageRank, k-shell, etc. We investigate the empirical diffusion data in a large scale online social community -- LiveJournal. With this extensive dataset, we find that various measures can convey very distinct information of nodes. Of all the users in LiveJournal social network, only a small fraction of them involve in spreading. For the spreading processes in Li...

  7. 9 CFR 319.762 - Ham spread, tongue spread, and similar products.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Ham spread, tongue spread, and similar products. 319.762 Section 319.762 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Salads and Meat Spreads § 319.762 Ham spread, tongue spread, and similar products. “Ham Spread,” “Tongue...

  8. Cortical Correlates of Fitts’ Law

    Directory of Open Access Journals (Sweden)

    Peter eIfft

    2011-12-01

    Full Text Available Fitts' law describes the fundamental trade-off between movement accuracy and speed: It states that the duration of reaching movements is a function of target size and distance. While Fitts' law has been extensively studied in ergonomics and has guided the design of human-computer interfaces, there have been few studies on its neuronal correlates. To elucidate sensorimotor cortical activity underlying Fitts’ law, we implanted two monkeys with multielectrode arrays in the primary motor (M1 and primary somatosensory (S1 cortices. The monkeys performed reaches with a joystick-controlled cursor towards targets of different size. The reaction time, movement time and movement velocity changed with target size, and M1 and S1 activity reflected these changes. Moreover, modifications of cortical activity could not be explained by changes of movement parameters alone, but required target size as an additional parameter. Neuronal representation of target size was especially prominent during the early reaction time period where it influenced the slope of the firing rate rise preceding movement initiation. During the movement period, cortical activity was mostly correlated with movement velocity. Neural decoders were applied to simultaneously decode target size and motor parameters from cortical modulations. We suggest using such classifiers to improve neuroprosthetic control.

  9. Olive oil in food spreads

    National Research Council Canada - National Science Library

    Blanco Muñoz, Miguel A

    2004-01-01

    .... The use of olive oil to prepare fat spread opens new insights into the commercial development of healthy novel foods with a positive image in terms of consumer appeal.La hidrogenación química de los...

  10. Worldwide spreading of economic crisis

    CERN Document Server

    Garas, Antonios; Rozenblat, Celine; Tomassini, Marco; Havlin, Shlomo

    2010-01-01

    We model the spreading of a crisis by constructing a global economic network and applying the Susceptible-Infected-Recovered (SIR) epidemic model with a variable probability of infection. The probability of infection depends on the strength of economic relations between the pair of countries, and the strength of the target country. It is expected that a crisis which originates in a large country, such as the USA, has the potential to spread globally, like the recent crisis. Surprisingly we show that also countries with much lower GDP, such as Belgium, are able to initiate a global crisis. Using the {\\it k}-shell decomposition method to quantify the spreading power (of a node), we obtain a measure of ``centrality'' as a spreader of each country in the economic network. We thus rank the different countries according to the shell they belong to, and find the 12 most central countries. These countries are the most likely to spread a crisis globally. Of these 12 only six are large economies, while the other six ar...

  11. Spreading dynamics in complex networks

    Science.gov (United States)

    Pei, Sen; Makse, Hernán A.

    2013-12-01

    Searching for influential spreaders in complex networks is an issue of great significance for applications across various domains, ranging from epidemic control, innovation diffusion, viral marketing, and social movement to idea propagation. In this paper, we first display some of the most important theoretical models that describe spreading processes, and then discuss the problem of locating both the individual and multiple influential spreaders respectively. Recent approaches in these two topics are presented. For the identification of privileged single spreaders, we summarize several widely used centralities, such as degree, betweenness centrality, PageRank, k-shell, etc. We investigate the empirical diffusion data in a large scale online social community—LiveJournal. With this extensive dataset, we find that various measures can convey very distinct information of nodes. Of all the users in the LiveJournal social network, only a small fraction of them are involved in spreading. For the spreading processes in LiveJournal, while degree can locate nodes participating in information diffusion with higher probability, k-shell is more effective in finding nodes with a large influence. Our results should provide useful information for designing efficient spreading strategies in reality.

  12. Cortical myoclonus in Huntington's disease.

    Science.gov (United States)

    Thompson, P D; Bhatia, K P; Brown, P; Davis, M B; Pires, M; Quinn, N P; Luthert, P; Honovar, M; O'Brien, M D; Marsden, C D

    1994-11-01

    We describe three patients with Huntington's disease, from two families, in whom myoclonus was the predominant clinical feature. The diagnosis was confirmed at autopsy in two cases and by DNA analysis in all three. These patients all presented before the age of 30 years and were the offspring of affected fathers. Neurophysiological studies documented generalised and multifocal action myoclonus of cortical origin that was strikingly stimulus sensitive, without enlargement of the cortical somatosensory evoked potential. The myoclonus improved with piracetam therapy in one patient and a combination of sodium valproate and clonazepam in the other two. Cortical reflex myoclonus is a rare but disabling component of the complex movement disorder of Huntington's disease, which may lead to substantial diagnostic difficulties.

  13. Adolescence depressions

    National Research Council Canada - National Science Library

    Matot, J P

    2009-01-01

    This article considers the depressive problematics emerging during adolescence in the frame of the transformations that characterize this period of life, with a focus on the interference of socio-cultural dimensions...

  14. Postpartum Depression

    DEFF Research Database (Denmark)

    Smith-Nielsen, Johanne

    Background: In three academic articles, this PhD thesis investigates maternal postpartum depression (PPD) as a risk factor for the infant-mother attachment and infant development. Previous studies have been contradictory with respect to the question of whether PPD can have long term effects...... on offspring. This may be due to not differing between when PPD is only occurring in the postpartum period and when effects are also due to ongoing or recurrent depression. However, it may also be due to viewing maternal depression as a unitary construct, and not considering underlying maternal psychological...... difficulties which may moderate potential adverse effects. The present thesis investigates two potential maternal moderators of risk:. Comorbid personality disorder and adult attachment insecurity. Moreover, the question of early environmental effects of PPD versus effects of later or ongoing depression...

  15. Grid cells and cortical representation.

    Science.gov (United States)

    Moser, Edvard I; Roudi, Yasser; Witter, Menno P; Kentros, Clifford; Bonhoeffer, Tobias; Moser, May-Britt

    2014-07-01

    One of the grand challenges in neuroscience is to comprehend neural computation in the association cortices, the parts of the cortex that have shown the largest expansion and differentiation during mammalian evolution and that are thought to contribute profoundly to the emergence of advanced cognition in humans. In this Review, we use grid cells in the medial entorhinal cortex as a gateway to understand network computation at a stage of cortical processing in which firing patterns are shaped not primarily by incoming sensory signals but to a large extent by the intrinsic properties of the local circuit.

  16. Spreading depolarization monitoring in neurocritical care of acute brain injury.

    Science.gov (United States)

    Hartings, Jed A

    2017-04-01

    Spreading depolarizations are unique in being discrete pathologic entities that are well characterized experimentally and also occur commonly in patients with substantial acute brain injury. Here, we review essential concepts in depolarization monitoring, highlighting its clinical significance, interpretation, and future potential. Cortical lesion development in diverse animal models is mediated by tissue waves of mass spreading depolarization that cause the toxic loss of ion homeostasis and limit energy substrate supply through associated vasoconstriction. The signatures of such deterioration are observed in electrocorticographic recordings from perilesional cortex of patients with acute stroke or brain trauma. Experimental work suggests that depolarizations are triggered by energy supply-demand mismatch in focal hotspots of the injury penumbra, and depolarizations are usually observed clinically when other monitoring variables are within recommended ranges. These results suggest that depolarizations are a sensitive measure of relative ischemia and ongoing secondary injury, and may serve as a clinical guide for personalized, mechanistically targeted therapy. Both existing and future candidate therapies offer hope to limit depolarization recurrence. Electrocorticographic monitoring of spreading depolarizations in patients with acute brain injury provides a sensitive measure of relative energy shortage in focal, vulnerable brains regions and indicates ongoing secondary damage. Depolarization monitoring holds potential for targeted clinical trial design and implementation of precision medicine approaches to acute brain injury therapy.

  17. Paroxysmal kinesigenic dyskinesia : Cortical or non-cortical origin

    NARCIS (Netherlands)

    van Strien, Teun W.; van Rootselaar, Anne-Fleur; Hilgevoord, Anthony A. J.; Linssen, Wim H. J. P.; Groffen, Alexander J. A.; Tijssen, Marina A. J.

    2012-01-01

    Paroxysmal kinesigenic dyskinesia (PKD) is characterized by involuntary dystonia and/or chorea triggered by a sudden movement. Cases are usually familial with an autosomal dominant inheritance. Hypotheses regarding the pathogenesis of PKD focus on the controversy whether PKD has a cortical or non-co

  18. 5-羟色胺对皮层扩展性抑制的影响及大川芎丸的干预作用%Influence of 5-HT on Cortical Spreading Depression and the Pharmacological Effect of Dachuanxiong Pill

    Institute of Scientific and Technical Information of China (English)

    杨洪军; 边宝林; 王永炎

    2005-01-01

    目的:观察5-羟色胺(5-HT)对皮层扩展性抑制(CSD)的增强作用以及大川芎丸的干预作用.方法:利用KCL诱发CSD,采用玻璃微电极记录CSD的电生理变化.腹腔注射5-羟基色胺酸(5-HTP)造成高5-HT状态,以观察5-HT对CSD的增强作用;连续灌胃大川芎丸7d后、以观察该药对正常状态和高5-HT状态下CSD的干预作用.结果:5-HT可以明显延长CSD的持续时间.大川芎丸可以降低正常状态CSD的幅度和出现个数;缩短高5-HT状态下的CSD持续时间.结论:5-HT对CSD具有明显的增强作用;大川芎丸可以抑制CSD,可能是其治疗偏头痛的作用机制之一.

  19. Recurrent Spontaneous Spreading Depolarizations Facilitate Acute Dendritic Injury in the Ischemic Penumbra

    OpenAIRE

    Risher, W Christopher; Ard, Deborah; Yuan, Jianghe; Kirov, Sergei A.

    2010-01-01

    Spontaneous spreading depolarizations (SDs) occur in the penumbra surrounding ischemic core. These SDs, often referred to as peri-infarct depolarizations, cause vasoconstriction and recruitment of the penumbra into the ischemic core in the critical first hours after focal ischemic stroke; however, the real-time spatiotemporal dynamics of SD-induced injury to synaptic circuitry in the penumbra remain unknown. A modified cortical photothrombosis model was used to produce a square-shaped lesion ...

  20. Spreading lengths of Hermite polynomials

    CERN Document Server

    Sánchez-Moreno, P; Manzano, D; Yáñez, R; 10.1016/j.cam.2009.09.043

    2009-01-01

    The Renyi, Shannon and Fisher spreading lengths of the classical or hypergeometric orthogonal polynomials, which are quantifiers of their distribution all over the orthogonality interval, are defined and investigated. These information-theoretic measures of the associated Rakhmanov probability density, which are direct measures of the polynomial spreading in the sense of having the same units as the variable, share interesting properties: invariance under translations and reflections, linear scaling and vanishing in the limit that the variable tends towards a given definite value. The expressions of the Renyi and Fisher lengths for the Hermite polynomials are computed in terms of the polynomial degree. The combinatorial multivariable Bell polynomials, which are shown to characterize the finite power of an arbitrary polynomial, play a relevant role for the computation of these information-theoretic lengths. Indeed these polynomials allow us to design an error-free computing approach for the entropic moments (w...

  1. Epidemic spreading by objective traveling

    Science.gov (United States)

    Tang, Ming; Liu, Zonghua; Li, Baowen

    2009-07-01

    A fundamental feature of agent traveling in social networks is that traveling is usually not a random walk but with a specific destination and goes through the shortest path from starting to destination. A serious consequence of the objective traveling is that it may result in a fast epidemic spreading, such as SARS etc. In this letter we present a reaction-traveling model to study how the objective traveling influences the epidemic spreading. We consider a random scale-free meta-population network with sub-population at each node. Through a SIS model we theoretically prove that near the threshold of epidemic outbreak, the objective traveling can significantly enhance the final infected population and the infected fraction at a node is proportional to its betweenness for the traveling agents and approximately proportional to its degree for the non-traveling agents. Numerical simulations have confirmed the theoretical predictions.

  2. Equatorial Spread F Fossil Plumes

    Science.gov (United States)

    2010-11-01

    Satyanarayana , P., and Ossakow, S. L.: The morphology of a multi-bubble system in the ionosphere, J. Geophys. Res., 88, 5528–5536, 1983. de La Beaujardiere...Haerendel, G.: Theory of equatorial spread F , preprint, Max Planck Inst. Extraterr. Phys., Munich, Germany, 1974. Haerendel, G., Eccles, J. V ., and...weather issues, J. Atmos. Terr. Phys., 58, 1527–1574, 1996. Sekar, R., Chakrabarty, D., Sarkhel, S., Patra, A. K., Devasia, C. V ., and Kelley, M. C

  3. Technique of green mulch spreading

    OpenAIRE

    Schäfer, Winfried; Väisänen, Jaana; Pihala, Marjo

    2001-01-01

    Finland’s policy of subsidising the conversion to organic production precipitated the rapid growth of organic farming in the 1990’s. As a consequence, many stockless farms encountered the problems of nitrogen deficit, poor grain quality, and weed control. Since the spreading of green mulch on cash crops is very common especially in tropical agriculture, organic fertilisers like green mulch may be an alternative that would compensate for the prohibition on the use of mineral N-fertilisers. How...

  4. Quality Improvement of Cheese Spread

    Science.gov (United States)

    2008-02-25

    Annatto (2% bixin) 3.5 mL Use as needed to conform color Vitamin A 0.14 0.003 Not less than 800 retinol units Added to comply with product...for samples with citrates (CIT) and altered levels of phosphates (LP) (Table 7). Although the citrates and phosphates have similar ionic components...Effect of vitamins The guidelines for cheese spread fortification include the addition of retinol (vitamin A), thiamine (vitamin B1), pyridoxine

  5. Physically Protected Spread Spectrum Communications

    Science.gov (United States)

    2016-04-14

    for the FH system in those days was because of implementation issues, such as a frequency -ringing problem , which occurred whenever a frequency was...PS-TR-2016-0046 HAS BEEN REVIEWED AND IS APPROVED FOR PUBLICATION IN ACCORDANCE WITH ASSIGNED DISTRIBUTION STATEMENT. KHANH PHAM PAUL D. LEVAN...keying (MPSK) and M-ary quadrature amplitude-shift keying (MQAM) for a slow frequency hopping (FH) spread spectrum (SS) system because, recently

  6. Face activated neurodynamic cortical networks.

    Science.gov (United States)

    Susac, Ana; Ilmoniemi, Risto J; Ranken, Doug; Supek, Selma

    2011-05-01

    Previous neuroimaging studies have shown that complex visual stimuli, such as faces, activate multiple brain regions, yet little is known on the dynamics and complexity of the activated cortical networks during the entire measurable evoked response. In this study, we used simulated and face-evoked empirical MEG data from an oddball study to investigate the feasibility of accurate, efficient, and reliable spatio-temporal tracking of cortical pathways over prolonged time intervals. We applied a data-driven, semiautomated approach to spatio-temporal source localization with no prior assumptions on active cortical regions to explore non-invasively face-processing dynamics and their modulation by task. Simulations demonstrated that the use of multi-start downhill simplex and data-driven selections of time intervals submitted to the Calibrated Start Spatio-Temporal (CSST) algorithm resulted in improved accuracy of the source localization and the estimation of the onset of their activity. Locations and dynamics of the identified sources indicated a distributed cortical network involved in face processing whose complexity was task dependent. This MEG study provided the first non-invasive demonstration, agreeing with intracranial recordings, of an early onset of the activity in the fusiform face gyrus (FFG), and that frontal activation preceded parietal for responses elicited by target faces.

  7. Drop Spreading with Random Viscosity

    Science.gov (United States)

    Xu, Feng; Jensen, Oliver

    2016-11-01

    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  8. Epidemic Spread in Human Networks

    CERN Document Server

    Sahneh, Faryad Darabi

    2011-01-01

    One of the popular dynamics on complex networks is the epidemic spreading. An epidemic model describes how infections spread throughout a network. Among the compartmental models used to describe epidemics, the Susceptible-Infected-Susceptible (SIS) model has been widely used. In the SIS model, each node can be susceptible, become infected with a given infection rate, and become again susceptible with a given curing rate. In this paper, we add a new compartment to the classic SIS model to account for human response to epidemic spread. Each individual can be infected, susceptible, or alert. Susceptible individuals can become alert with an alerting rate if infected individuals exist in their neighborhood. An individual in the alert state is less probable to become infected than an individual in the susceptible state; due to a newly adopted cautious behavior. The problem is formulated as a continuous-time Markov process on a general static graph and then modeled into a set of ordinary differential equations using...

  9. Spread of entanglement and causality

    CERN Document Server

    Casini, Horacio; Mezei, Márk

    2015-01-01

    We investigate causality constraints on the time evolution of entanglement entropy after a global quench in relativistic theories. We first provide a general proof that the so-called tsunami velocity is bounded by the speed of light. We then generalize the free particle streaming model of arXiv:cond-mat/0503393 to general dimensions and to an arbitrary entanglement pattern of the initial state. In more than two spacetime dimensions the spread of entanglement in these models is highly sensitive to the initial entanglement pattern, but we are able to prove an upper bound on the normalized rate of growth of entanglement entropy, and hence the tsunami velocity. The bound is smaller than what one gets for quenches in holographic theories, which highlights the importance of interactions in the spread of entanglement in many-body systems. We propose an interacting model which we believe provides an upper bound on the spread of entanglement for interacting relativistic theories. In two spacetime dimensions with multi...

  10. Spread of entanglement and causality

    Science.gov (United States)

    Casini, Horacio; Liu, Hong; Mezei, Márk

    2016-07-01

    We investigate causality constraints on the time evolution of entanglement entropy after a global quench in relativistic theories. We first provide a general proof that the so-called tsunami velocity is bounded by the speed of light. We then generalize the free particle streaming model of [1] to general dimensions and to an arbitrary entanglement pattern of the initial state. In more than two spacetime dimensions the spread of entanglement in these models is highly sensitive to the initial entanglement pattern, but we are able to prove an upper bound on the normalized rate of growth of entanglement entropy, and hence the tsunami velocity. The bound is smaller than what one gets for quenches in holographic theories, which highlights the importance of interactions in the spread of entanglement in many-body systems. We propose an interacting model which we believe provides an upper bound on the spread of entanglement for interacting relativistic theories. In two spacetime dimensions with multiple intervals, this model and its variations are able to reproduce intricate results exhibited by holographic theories for a significant part of the parameter space. For higher dimensions, the model bounds the tsunami velocity at the speed of light. Finally, we construct a geometric model for entanglement propagation based on a tensor network construction for global quenches.

  11. Cortical factor feedback model for cellular locomotion and cytofission.

    Directory of Open Access Journals (Sweden)

    Shin I Nishimura

    2009-03-01

    Full Text Available Eukaryotic cells can move spontaneously without being guided by external cues. For such spontaneous movements, a variety of different modes have been observed, including the amoeboid-like locomotion with protrusion of multiple pseudopods, the keratocyte-like locomotion with a widely spread lamellipodium, cell division with two daughter cells crawling in opposite directions, and fragmentations of a cell to multiple pieces. Mutagenesis studies have revealed that cells exhibit these modes depending on which genes are deficient, suggesting that seemingly different modes are the manifestation of a common mechanism to regulate cell motion. In this paper, we propose a hypothesis that the positive feedback mechanism working through the inhomogeneous distribution of regulatory proteins underlies this variety of cell locomotion and cytofission. In this hypothesis, a set of regulatory proteins, which we call cortical factors, suppress actin polymerization. These suppressing factors are diluted at the extending front and accumulated at the retracting rear of cell, which establishes a cellular polarity and enhances the cell motility, leading to the further accumulation of cortical factors at the rear. Stochastic simulation of cell movement shows that the positive feedback mechanism of cortical factors stabilizes or destabilizes modes of movement and determines the cell migration pattern. The model predicts that the pattern is selected by changing the rate of formation of the actin-filament network or the threshold to initiate the network formation.

  12. Active Chemical Thermodynamics promoted by activity of cortical actin

    Science.gov (United States)

    Bhattacharya, Bhaswati; Chaudhuri, Abhishek; Gowrishankar, Kripa; Rao, Madan

    2011-03-01

    The spatial distribution and dynamics of formation and breakup of the nanoclusters of cell surface proteins is controlled by the active remodeling dynamics of the underlying cortical actin. To explain these observations, we have proposed a novel mechanism of nanoclustering, involving the transient binding to and advection along constitutively occuring ``asters'' of cortical actin. We study the consequences of such active actin-based clustering, in the context of chemical reactions involving conformational changes of cell surface proteins. We find that the active remodeling of cortical actin, can give rise to a dramatic increase in efficiency and extent of conformational spread, even at low levels of expression at the cell surface. We define a activity temperature (τa) arising due to actin activities which can be used to describe chemical thermodynamics of the system. We plot TTT (time-temparature-transformation) curves and compute the Arrhenius factors which depend on τa . With this, the active asters can be treated as enzymes whose enzymatic reaction rate can be related to the activity.

  13. Reverse preferential spread in complex networks

    Science.gov (United States)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  14. Basal forebrain degeneration precedes and predicts the cortical spread of Alzheimer's pathology

    OpenAIRE

    Schmitz, Taylor W.; Nathan Spreng, R.; Weiner, Michael W.; Aisen, Paul; Petersen, Ronald; Jack, Clifford R; Jagust, William; Trojanowki, John Q.; Toga, Arthur W; Beckett, Laurel; Green, Robert C.; Saykin, Andrew J.; Morris, John; Leslie M Shaw; Khachaturian, Zaven

    2016-01-01

    There is considerable debate whether Alzheimer's disease (AD) originates in basal forebrain or entorhinal cortex. Here we examined whether longitudinal decreases in basal forebrain and entorhinal cortex grey matter volume were interdependent and sequential. In a large cohort of age-matched older adults ranging from cognitively normal to AD, we demonstrate that basal forebrain volume predicts longitudinal entorhinal degeneration. Models of parallel degeneration or entorhinal origin received ne...

  15. Geodynamic environments of ultra-slow spreading

    Science.gov (United States)

    Kokhan, Andrey; Dubinin, Evgeny

    2015-04-01

    Ultra-slow spreading is clearly distinguished as an outstanding type of crustal accretion by recent studies. Spreading ridges with ultra-slow velocities of extension are studied rather well. But ultra-slow spreading is characteristic feature of not only spreading ridges, it can be observed also on convergent and transform plate boundaries. Ultra-slow spreading is observed now or could have been observed in the past in the following geodynamic environments on divergent plate boundaries: 1. On spreading ridges with ultra-slow spreading, both modern (f.e. Gakkel, South-West Indian, Aden spreading center) and ceased (Labrador spreading center, Aegir ridge); 2. During transition from continental rifting to early stages of oceanic spreading (all spreading ridges during incipient stages of their formation); 3. During incipient stages of formation of spreading ridges on oceanic crust as a result of ridge jumps and reorganization of plate boundaries (f.e. Mathematicians rise and East Pacific rise); 4. During propagation of spreading ridge into the continental crust under influence of hotspot (Aden spreading center and Afar triple junction), under presence of strike-slip faults preceding propagation (possibly, rift zone of California Bay). Ultra-slow spreading is observed now or could have been observed in the past in the following geodynamic environments on transform plate boundaries: 1. In transit zones between two "typical" spreading ridges (f.e. Knipovich ridge); 2. In semi strike-slip/extension zones on the oceanic crust (f.e. American-Antarctic ridge); 3. In the zones of local extension in regional strike-slip areas in pull-apart basins along transform boundaries (Cayman trough, pull-apart basins of the southern border of Scotia plate). Ultra-slow spreading is observed now or could have been observed in the past in the following geodynamic environments on convergent plate boundaries: 1. During back-arc rifting on the stage of transition into back-arc spreading (central

  16. Motor cortical thresholds and cortical silent periods in epilepsy.

    Science.gov (United States)

    Tataroglu, Cengiz; Ozkiziltan, Safa; Baklan, Baris

    2004-10-01

    We studied motor cortical thresholds (TIs) and cortical silent periods (SPs) evoked by transcranial magnetic stimulation (TMS) in 110 epileptic patients. Sixty-two had primary generalised, 48 had partial type seizures. Fifteen out 110 patients were analysed both before and after anticonvulsant medication. Our aims were to evaluate the TI levels and the duration of SPs in patients with epilepsy and to determine the reliability of TMS in patients with epilepsy. There was no negative effect of TMS on the clinical status and EEG findings in patients with epilepsy. TIs obtained from patients with partial epilepsy were higher than those obtained from both controls and primary epileptics. The duration of SP in patients with primary epileptics was more prolonged than those obtained from controls. There was no correlation between EEG lateralisation and both SP duration and TI values. In de novo patient group, SP duration was significantly prolonged after anticonvulsant medication. We concluded that TMS is a reliable electrophysiological investigation in patients with epilepsy. The analysis of SP duration may be an appropriate investigation in monitoring the effect of anticonvulsant medication on the cortical inhibitory activity.

  17. The neuropathological basis for depression in Parkinson's disease.

    Science.gov (United States)

    Frisina, Pasquale G; Haroutunian, Vahram; Libow, Leslie S

    2009-02-01

    Depression is found in 30-40% of all patients with Parkinson's disease (PD), but its etiology is unclear. Using neuropathology as a signpost for neurotransmitter function, we investigated the prevalence of pathological features found at postmortem and sought to uncover differences between depressed (n=11) and non-depressed (n=9) elderly PD patients. The results indicate a higher prevalence of pathological features in depressed compared to non-depressed PD patients, particularly in catecholamine areas of the brain; the locus coeruleus (neuronal loss: odds ratio=7.2, p=08; gliosis: odds ratio=18.0, p=008); dorsal vagus nerve (gliosis: odds ratio=7.63, p<0.05), and substantia nigra pars compacta (gliosis: odds ratio=2.85, ns). However, neuropathological differences were absent in the dorsal raphe nuclei, amygdala, and cortical regions. Our evidence suggests that depression in PD is related more to catecholaminergic than serotonergic system dysfunction.

  18. TDCS increases cortical excitability: direct evidence from TMS-EEG.

    Science.gov (United States)

    Romero Lauro, Leonor J; Rosanova, Mario; Mattavelli, Giulia; Convento, Silvia; Pisoni, Alberto; Opitz, Alexander; Bolognini, Nadia; Vallar, Giuseppe

    2014-09-01

    Despite transcranial direct current stimulation (tDCS) is increasingly used in experimental and clinical settings, its precise mechanisms of action remain largely unknown. At a neuronal level, tDCS modulates the resting membrane potential in a polarity-dependent fashion: anodal stimulation increases cortical excitability in the stimulated region, while cathodal decreases it. So far, the neurophysiological underpinnings of the immediate and delayed effects of tDCS, and to what extent the stimulation of a given cerebral region may affect the activity of anatomically connected regions, remain unclear. In the present study, we used a combination of Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG) in order to explore local and global cortical excitability modulation during and after active and sham tDCS. Single pulse TMS was delivered over the left posterior parietal cortex (PPC), before, during, and after 15 min of tDCS over the right PPC, while EEG was recorded from 60 channels. For each session, indexes of global and local cerebral excitability were obtained, computed as global and local mean field power (Global Mean Field Power, GMFP and Local Mean Field Power, LMFP) on mean TMS-evoked potentials (TEPs) for three temporal windows: 0-50, 50-100, and 100-150 msec. The global index was computed on all 60 channels. The local indexes were computed in six clusters of electrodes: left and right in frontal, parietal and temporal regions. GMFP increased, compared to baseline, both during and after active tDCS in the 0-100 msec temporal window. LMFP increased after the end of stimulation in parietal and frontal clusters bilaterally, while no difference was found in the temporal clusters. In sum, a diffuse rise of cortical excitability occurred, both during and after active tDCS. This evidence highlights the spreading of the effects of anodal tDCS over remote cortical regions of stimulated and contralateral hemispheres.

  19. Plume spread and atmospheric stability

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The horizontal spread of a plume in atmospheric dispersion can be described by the standard deviation of horizontal direction. The widely used Pasquill-Gifford classes of atmospheric stability have assigned typical values of the standard deviation of horizontal wind direction and of the lapse rate. A measured lapse rate can thus be used to estimate the standard deviation of wind direction. It is examined by means of a large dataset of fast wind measurements how good these estimates are. (author) 1 fig., 2 refs.

  20. Liquid Spreading under Nanoscale Confinement

    Science.gov (United States)

    Checco, Antonio

    2009-03-01

    Dynamic atomic force microscopy in the noncontact regime is used to study the morphology of a nonvolatile liquid (squalane) as it spreads along wettable nanostripes embedded in a nonwettable surface. Results show that the liquid profile depends on the amount of lateral confinement imposed by the nanostripes, and it is truncated at the microscopic contact line in good qualitative agreement with classical mesoscale hydrodynamics. However, the width of the contact line is found to be significantly larger than expected theoretically. This behavior may originate from small chemical inhomogeneity of the patterned stripes as well as from thermal fluctuations of the contact line.

  1. Spreading widths of doorway states

    Energy Technology Data Exchange (ETDEWEB)

    De Pace, A., E-mail: depace@to.infn.i [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via P. Giuria 1, I-10125 Torino (Italy); Molinari, A. [Dipartimento di Fisica Teorica dell' Universita di Torino, via P. Giuria 1, I-10125 Torino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via P. Giuria 1, I-10125 Torino (Italy); Weidenmueller, H.A. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany)

    2011-01-01

    As a function of energy E, the average doorway strength function S(E)-bar of a doorway state is commonly assumed to be Lorentzian in shape and characterized by two parameters, the peak energy E{sub 0} and the spreading width {Gamma}{sup {down_arrow}}. The simple picture is modified when the density of background states that couple to the doorway state changes significantly in an energy interval of size {Gamma}{sup {down_arrow}}. For that case we derive an approximate analytical expression for S(E)-bar. We test our result successfully against numerical simulations. Our result may have important implications for shell-model calculations.

  2. Can Lupus Cause Depression?

    Science.gov (United States)

    ... lupus Living well with lupus Can lupus cause depression? Life with lupus can be challenging. With symptoms ... treatable illness called clinical depression. Symptoms of Clinical Depression People are considered clinically depressed when they have ...

  3. Older Adults and Depression

    Science.gov (United States)

    ... find more information? Reprints Share Older Adults and Depression Download PDF Download ePub Order a free hardcopy ... depression need treatment to feel better. Types of Depression There are several types of depression. The most ...

  4. Depression and Multiple Sclerosis

    Science.gov (United States)

    ... Symptoms Depression Share this page Facebook Twitter Email Depression Depression Fatigue Walking (Gait) Difficulties Numbness or Tingling ... away from addictive substances such as alcohol. Clinical depression It’s important to distinguish between mild, everyday “blues” — ...

  5. Migration Helps Spread Bird Flu Worldwide

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_161473.html Migration Helps Spread Bird Flu Worldwide Scientists recommend keeping ... birds can spread bird flu worldwide and monitoring migration routes could provide early warning of outbreaks, researchers ...

  6. Lexical Ambiguity: Making a Case against Spread

    Science.gov (United States)

    Kaplan, Jennifer J.; Rogness, Neal T.; Fisher, Diane G.

    2012-01-01

    We argue for decreasing the use of the word "spread" when describing the statistical idea of dispersion or variability in introductory statistics courses. In addition, we argue for increasing the use of the word "variability" as a replacement for "spread."

  7. Transcranial Magnetic Stimulation for the treatment of tinnitus: Effects on cortical excitability

    Directory of Open Access Journals (Sweden)

    Hajak Göran

    2007-07-01

    Full Text Available Abstract Background Low frequency repetitive transcranial magnetic stimulation (rTMS has been proposed as an innovative treatment for chronic tinnitus. The aim of the present study was to elucidate the underlying mechanism and to evaluate the relationship between clinical outcome and changes in cortical excitability. We investigated ten patients with chronic tinnitus who participated in a sham-controlled crossover treatment trial. Magnetic-resonance-imaging and positron-emission-tomography guided 1 Hz rTMS were performed over the auditory cortex on 5 consecutive days. Active and sham treatments were separated by one week. Parameters of cortical excitability (motor thresholds, intracortical inhibition, intracortical facilitation, cortical silent period were measured serially before and after rTMS treatment by using single- and paired-pulse transcranial magnetic stimulation. Clinical improvement was assessed with a standardized tinnitus-questionnaire. Results We noted a significant interaction between treatment response and changes in motor cortex excitability during active rTMS. Specifically, clinical improvement was associated with an increase in intracortical inhibition, intracortical facilitation and a prolongation of the cortical silent period. These results indicate that intraindividual changes in cortical excitability may serve as a correlate of response to rTMS treatment. Conclusion The observed alterations of cortical excitability suggest that low frequency rTMS may evoke long-term-depression like effects resulting in an improvement of subcortical inhibitory function.

  8. Unimodal primary sensory cortices are directly connected by long-range horizontal projections in the rat sensory cortex

    Directory of Open Access Journals (Sweden)

    Jimmy eStehberg

    2014-09-01

    Full Text Available Research based on functional imaging and neuronal recordings in the barrel cortex subdivision of primary somatosensory cortex (SI of the adult rat has revealed novel aspects of structure-function relationships in this cortex. Specifically, it has demonstrated that single whisker stimulation evokes subthreshold neuronal activity that spreads symmetrically within gray matter from the appropriate barrel area, crosses cytoarchitectural borders of SI and reaches deeply into other unimodal primary cortices such as primary auditory (AI and primary visual (VI. It was further demonstrated that this spread is supported by a spatially matching underlying diffuse network of border-crossing, long-range projections that could also reach deeply into AI and VI. Here we seek to determine whether such a network of border-crossing, long-range projections is unique to barrel cortex or characterizes also other primary, unimodal sensory cortices and therefore could directly connect them. Using anterograde (BDA and retrograde (CTb tract-tracing techniques, we demonstrate that such diffuse horizontal networks directly and mutually connect VI, AI and SI. These findings suggest that diffuse, border-crossing axonal projections connecting directly primary cortices are an important organizational motif common to all major primary sensory cortices in the rat. Potential implications of these findings for topics including cortical structure-function relationships, multisensory integration, functional imaging and cortical parcellation are discussed.

  9. Imprinting and recalling cortical ensembles.

    Science.gov (United States)

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  10. A framework for targeting alternative brain regions with repetitive transcranial magnetic stimulation in the treatment of depression

    NARCIS (Netherlands)

    Schutter, D.J.L.G.; Honk, E.J. van

    2005-01-01

    It has been argued that clinical depression is accompanied by reductions in cortical excitability of the left prefrontal cortex (PFC). In support of this, repetitive transcranial magnetic stimulation (rTMS), which is a method of enhancing cortical excitability, has shown antidepressant efficacy when

  11. Cortical sensorimotor integration: a hypothesis.

    Science.gov (United States)

    Batuev, A S

    1989-01-01

    A hypothesis is proposed that neocortex is constructed from structural neuronal modules (columns and rings). Each module is considered as unit for cortical sensorimotor integration. Complex functional relationships between modules can be arranged by intracortical inhibition participation. High pronounced neocortical plasticity ensures the process of continuous formation of various dominating operative constellations comprising stable neuronal modules whose component structure and distributive characteristic are determined by the dominant motivation and the central motor program.

  12. The spreading of misinformation online.

    Science.gov (United States)

    Del Vicario, Michela; Bessi, Alessandro; Zollo, Fabiana; Petroni, Fabio; Scala, Antonio; Caldarelli, Guido; Stanley, H Eugene; Quattrociocchi, Walter

    2016-01-19

    The wide availability of user-provided content in online social media facilitates the aggregation of people around common interests, worldviews, and narratives. However, the World Wide Web (WWW) also allows for the rapid dissemination of unsubstantiated rumors and conspiracy theories that often elicit rapid, large, but naive social responses such as the recent case of Jade Helm 15--where a simple military exercise turned out to be perceived as the beginning of a new civil war in the United States. In this work, we address the determinants governing misinformation spreading through a thorough quantitative analysis. In particular, we focus on how Facebook users consume information related to two distinct narratives: scientific and conspiracy news. We find that, although consumers of scientific and conspiracy stories present similar consumption patterns with respect to content, cascade dynamics differ. Selective exposure to content is the primary driver of content diffusion and generates the formation of homogeneous clusters, i.e., "echo chambers." Indeed, homogeneity appears to be the primary driver for the diffusion of contents and each echo chamber has its own cascade dynamics. Finally, we introduce a data-driven percolation model mimicking rumor spreading and we show that homogeneity and polarization are the main determinants for predicting cascades' size.

  13. [Parietal Cortices and Body Information].

    Science.gov (United States)

    Naito, Eiichi; Amemiya, Kaoru; Morita, Tomoyo

    2016-11-01

    Proprioceptive signals originating from skeletal muscles and joints contribute to the formation of both the human body schema and the body image. In this chapter, we introduce various types of bodily illusions that are elicited by proprioceptive inputs, and we discuss distinct functions implemented by different parietal cortices. First, we illustrate the primary importance of the motor network in the processing of proprioceptive (kinesthetic) signals originating from muscle spindles. Next, we argue that the right inferior parietal cortex, in concert with the inferior frontal cortex (both regions connected by the inferior branch of the superior longitudinal fasciculus-SLF III), may be involved in the conscious experience of body image. Further, we hypothesize other functions of distinct parietal regions: the association between internal hand motor representation with external object representation in the left inferior parietal cortex, visuo-kinesthetic processing in the bilateral posterior parietal cortices, and the integration of somatic signals from different body parts in the higher-order somatosensory parietal cortices. Our results indicate that a distinct parietal region, in concert with its anatomically and functionally connected frontal regions, probably plays specialized roles in the processing of body-related information.

  14. A Review of Selected Candidate Endophenotypes for Depression

    Science.gov (United States)

    Goldstein, Brandon L.; Klein, Daniel N.

    2014-01-01

    Endophenotypes are proposed to occupy an intermediate position in the pathway between genotype and phenotype in genetically complex disorders such as depression. To be considered an endophenotype, a construct must meet a set of criteria proposed by Gottesman and Gould (2003). In this qualitative review, we summarize evidence for each criterion for several putative endophenotypes for depression: neuroticism, morning cortisol, frontal asymmetry of cortical electrical activity, reward learning, and biases of attention and memory. Our review indicates that while there is strong support for some depression endophenotypes, other putative endophenotypes lack data or have inconsistent findings for core criteria. PMID:25006008

  15. The electrophysiological time course of the interaction of stimulus conflict and the multisensory spread of attention.

    Science.gov (United States)

    Zimmer, U; Itthipanyanan, S; Grent-'t-Jong, T; Woldorff, M G

    2010-05-01

    Previously, we have shown that spatial attention to a visual stimulus can spread across both space and modality to a synchronously presented but task-irrelevant sound arising from a different location, reflected by a late-onsetting, sustained, negative-polarity event-related potential (ERP) wave over frontal-central scalp sites, probably originating in part from the auditory cortices. Here we explore the influence of cross-modal conflict on the amplitude and temporal dynamics of this multisensory spreading-of-attention activity. Subjects attended selectively to one of two concurrently presented lateral visually-presented letter streams to perform a sequential comparison task, while ignoring task-irrelevant, centrally presented spoken letters that could occur synchronously with either the attended or unattended lateral visual letters and could be either congruent or incongruent with them. Extracted auditory ERPs revealed that, collapsed across congruency conditions, attentional spreading across modalities started at approximately 220 ms, replicating our earlier findings. The interaction between attentional spreading and conflict occurred beginning at approximately 300 ms, with attentional-spreading activity being larger for incongruent trials. Thus, the increased processing of an incongruent, task-irrelevant sound in a multisensory stimulation appeared to occur some time after attention has spread from the attended visual part to the ignored auditory part, presumably reflecting the conflict detection and associated attentional capture requiring accrual of some multisensory interaction processes at a higher-level semantic processing stage.

  16. Rumor spreading in gaming social networks

    CERN Document Server

    Zhang, Yichao; Guan, Jihong; Zhou, Shuigeng

    2011-01-01

    So far, the focus on rumor spreading are mainly on some simple backgrounds, in other words, only taking consideration of the overall topological influences on its dynamical behavior. However, in the prospect of the individuality, personal strategies in the social networks play a more non-trivial role in the real social networks. To fill this gap, we will investigate the rumor spreading in gaming social networks. Our analysis is supported by the results of numerical simulations. We observe that the original rumor is still the most well known edition in case that the content is modified by the defectors. However, the portion decays with the stimulus generally. For the case that defectors keep silence in the spreading process, the scale of spreading decays with stimulus generally, suggesting the rumor can hardly spread in a community of defectors. This highlights the key role that stimulus plays in rumor spreading and the necessity to study information spreading in competitive circumstances.

  17. Random Information Spread in Networks

    CERN Document Server

    Lapus, Raymond; Tittmann, Peter

    2010-01-01

    Let G=(V,E) be an undirected loopless graph with possible parallel edges and s and t be two vertices of G. Assume that vertex s is labelled at the initial time step and that every labelled vertex copies its labelling to neighbouring vertices along edges with one labelled endpoint independently with probability p in one time step. In this paper, we establish the equivalence between the expected s-t first arrival time of the above spread process and the notion of the stochastic shortest s-t path. Moreover, we give a short discussion of analytical results on special graphs including the complete graph and s-t series-parallel graphs. Finally, we propose some lower bounds for the expected s-t first arrival time.

  18. Bank Lending, Housing and Spreads

    DEFF Research Database (Denmark)

    Aslam, Aqib; Santoro, Emiliano

    The framework presented in this paper takes its cue from recent financial events and attempts to develop a tractable framework for policy analysis of macro-linkages, in particular a first attempt at the integration of an independent profit-maximising banking sector that lends to and borrows from...... agents in the economy, and through which changes in the monetary policy rate by the central bank are transmitted. The inter-linkages between housing and the role of the banking sector in the transmission of monetary policy is emphasized. Two competing effects are highlighted: (i) a financial accelerator...... channel, due to the presence of collateralized borrowers, and (ii) a banking attenuator effect, which crucially arises from the spread in interest rates caused by the introduction of monopolistically competitive financial intermediaries. We show how the classical amplification mechanism explored in models...

  19. Interpolating point spread function anisotropy

    CERN Document Server

    Gentile, M; Meylan, G

    2012-01-01

    Planned wide-field weak lensing surveys are expected to reduce the statistical errors on the shear field to unprecedented levels. In contrast, systematic errors like those induced by the convolution with the point spread function (PSF) will not benefit from that scaling effect and will require very accurate modeling and correction. While numerous methods have been devised to carry out the PSF correction itself, modeling of the PSF shape and its spatial variations across the instrument field of view has, so far, attracted much less attention. This step is nevertheless crucial because the PSF is only known at star positions while the correction has to be performed at any position on the sky. A reliable interpolation scheme is therefore mandatory and a popular approach has been to use low-order bivariate polynomials. In the present paper, we evaluate four other classical spatial interpolation methods based on splines (B-splines), inverse distance weighting (IDW), radial basis functions (RBF) and ordinary Kriging...

  20. Bank Lending, Housing and Spreads

    DEFF Research Database (Denmark)

    Aslam, Aqib; Santoro, Emiliano

    of private borrowing between collaterally-constrained 'impatient' households and unconstrained 'patient' households, such as those put forward by Kiyotaki and Moore (1997) and Iacoviello (2005), is counteracted by the banking attenuator effect, given an endogenous steady state spread between loan and savings......The framework presented in this paper takes its cue from recent financial events and attempts to develop a tractable framework for policy analysis of macro-linkages, in particular a first attempt at the integration of an independent profit-maximising banking sector that lends to and borrows from...... agents in the economy, and through which changes in the monetary policy rate by the central bank are transmitted. The inter-linkages between housing and the role of the banking sector in the transmission of monetary policy is emphasized. Two competing effects are highlighted: (i) a financial accelerator...

  1. Detection and quantification of regional cortical gray matter damage in multiple sclerosis utilizing gradient echo MRI

    Directory of Open Access Journals (Sweden)

    Jie Wen

    2015-01-01

    Full Text Available Cortical gray matter (GM damage is now widely recognized in multiple sclerosis (MS. The standard MRI does not reliably detect cortical GM lesions, although cortical volume loss can be measured. In this study, we demonstrate that the gradient echo MRI can reliably and quantitatively assess cortical GM damage in MS patients using standard clinical scanners. High resolution multi-gradient echo MRI was used for regional mapping of tissue-specific MRI signal transverse relaxation rate values (R2* in 10 each relapsing–remitting, primary-progressive and secondary-progressive MS subjects. A voxel spread function method was used to correct artifacts induced by background field gradients. R2* values from healthy controls (HCs of varying ages were obtained to establish baseline data and calculate ΔR2* values – age-adjusted differences between MS patients and HC. Thickness of cortical regions was also measured in all subjects. In cortical regions, ΔR2* values of MS patients were also adjusted for changes in cortical thickness. Symbol digit modalities (SDMT and paced auditory serial addition (PASAT neurocognitive tests, as well as Expanded Disability Status Score, 25-foot timed walk and nine-hole peg test results were also obtained on all MS subjects. We found that ΔR2* values were lower in multiple cortical GM and normal appearing white matter (NAWM regions in MS compared with HC. ΔR2* values of global cortical GM and several specific cortical regions showed significant (p < 0.05 correlations with SDMT and PASAT scores, and showed better correlations than volumetric measures of the same regions. Neurological tests not focused on cognition (Expanded Disability Status Score, 25-foot timed walk and nine-hole peg tests showed no correlation with cortical GM ΔR2* values. The technique presented here is robust and reproducible. It requires less than 10 min and can be implemented on any MRI scanner. Our results show that quantitative tissue-specific R2

  2. Default mode network dissociation in depressive and anxiety states.

    Science.gov (United States)

    Coutinho, Joana Fernandes; Fernandesl, Sara Veiga; Soares, José Miguel; Maia, Liliana; Gonçalves, Óscar Filipe; Sampaio, Adriana

    2016-03-01

    The resting state brain networks, particularly the Default Mode Network (DMN), have been found to be altered in several psychopathological conditions such as depression and anxiety. In this study we hypothesized that cortical areas of the DMN, particularly the anterior regions--medial prefrontal cortex and anterior cingulate cortex--would show an increased functional connectivity associated with both anxiety and depression. Twenty-four healthy participants were assessed using Hamilton Depression and Anxiety Rating Scales and completed a resting-state functional magnetic resonance imaging scan. Multiple regression was performed in order to identify which areas of the DMN were associated with anxiety and depression scores. We found that the functional connectivity of the anterior portions of DMN, involved in self-referential and emotional processes, was positively correlated with anxiety and depression scores, whereas posterior areas of the DMN, involved in episodic memory and perceptual processing were negatively correlated with anxiety and depression scores. The dissociation between anterior and posterior cortical midline regions, raises the possibility of a functional specialization within the DMN in terms of self-referential tasks and contributes to the understanding of the cognitive and affective alterations in depressive and anxiety states.

  3. Hamilton-Jacobi skeleton on cortical surfaces.

    Science.gov (United States)

    Shi, Y; Thompson, P M; Dinov, I; Toga, A W

    2008-05-01

    In this paper, we propose a new method to construct graphical representations of cortical folding patterns by computing skeletons on triangulated cortical surfaces. In our approach, a cortical surface is first partitioned into sulcal and gyral regions via the solution of a variational problem using graph cuts, which can guarantee global optimality. After that, we extend the method of Hamilton-Jacobi skeleton [1] to subsets of triangulated surfaces, together with a geometrically intuitive pruning process that can trade off between skeleton complexity and the completeness of representing folding patterns. Compared with previous work that uses skeletons of 3-D volumes to represent sulcal patterns, the skeletons on cortical surfaces can be easily decomposed into branches and provide a simpler way to construct graphical representations of cortical morphometry. In our experiments, we demonstrate our method on two different cortical surface models, its ability of capturing major sulcal patterns and its application to compute skeletons of gyral regions.

  4. Disorders of cortical formation: MR imaging features.

    Science.gov (United States)

    Abdel Razek, A A K; Kandell, A Y; Elsorogy, L G; Elmongy, A; Basett, A A

    2009-01-01

    The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.

  5. Changes in cortical plasticity across the lifespan

    Directory of Open Access Journals (Sweden)

    Catarina eFreitas

    2011-04-01

    Full Text Available Deterioration of motor and cognitive performance with advancing age is well documented, but its cause remains unknown. Animal studies dating back to the late 1970’s reveal that age-associated neurocognitive changes are linked to age-dependent changes in synaptic plasticity, including alterations of long-term potentiation and depression (LTP and LTD. Non-invasive brain stimulation techniques enable measurement of LTP- and LTD-like mechanisms of plasticity, in vivo, in humans, and may thus provide valuable insights. We examined the effects of a 40-second train of continuous theta-burst stimulation (cTBS to the motor cortex (600 stimuli, 3 pulses at 50 Hz applied at a frequency of 5 Hz on cortico-spinal excitability as measured by the motor evoked potentials (MEPs induced by single-pulse TMS before and after cTBS in the contralateral first dorsal interosseus muscle. Thirty-six healthy individuals aged 19 to 81 years old were studied in two sites (Boston, USA and Barcelona, Spain. The findings did not differ across study sites. We found that advancing age is negatively correlated with the duration of the effect of cTBS (r = -0.367; p = 0.028 and the overall amount of corticomotor suppression induced by cTBS (r = -0.478; p = 0.003, and positively correlated with the maximal suppression of amplitude on motor evoked responses in the target muscle (r = 0.420; p = 0.011. We performed magnetic resonance imaging (MRI-based individual morphometric analysis in a subset of subjects to demonstrate that these findings are not explained by age-related brain atrophy or differences in scalp-to-brain distance that could have affected the TBS effects. Our findings provide empirical evidence that the mechanisms of cortical plasticity area are altered with aging and their efficiency decreases across the human lifespan. This may critically contribute to motor and possibly cognitive decline.

  6. Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Paul A Muller

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP, presumably reflecting long-term depression (LTD -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1 reproduce cortico-spinal depression by LF rTMS in rats, (2 establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3 test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR, by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered.

  7. A Rare Hydrocephalus Complication: Cortical Blindness.

    Science.gov (United States)

    Ünal, Emre; Göçmen, Rahşan; Işıkay, Ayşe İlksen; Tekşam, Özlem

    2015-01-01

    Cortical blindness related to bilateral occipital lobe infarction is an extremely rare complication of hydrocephalus. Compression of the posterior cerebral artery, secondary to tentorial herniation, is the cause of occipital infarction. Particularly in children and mentally ill patients, cortical blindness may be missed. Therefore, early diagnosis and treatment of hydrocephalus is important. We present herein a child of ventricular shunt malfunction complicated by cortical blindness.

  8. Acute hepatic encephalopathy with diffuse cortical lesions

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, S.M.; Spreer, J.; Schumacher, M. [Section of Neuroradiology, Univ. of Freiburg (Germany); Els, T. [Dept. of Neurology, University of Freiburg (Germany)

    2001-07-01

    Acute hepatic encephalopathy is a poorly defined syndrome of heterogeneous aetiology. We report a 49-year-old woman with alcoholic cirrhosis and hereditary haemorrhagic telangiectasia who developed acute hepatic coma induced by severe gastrointestinal bleeding. Laboratory analysis revealed excessively elevated blood ammonia. MRI showed lesions compatible with chronic hepatic encephalopathy and widespread cortical signal change sparing the perirolandic and occipital cortex. The cortical lesions resembled those of hypoxic brain damage and were interpreted as acute toxic cortical laminar necrosis. (orig.)

  9. Effects of the muscarinic antagonists pirenzepine and gallamine on spontaneous and evoked responses of rat cerebral cortical neurones.

    Science.gov (United States)

    Swanson, T. H.; Phillis, J. W.

    1988-01-01

    1. The muscarinic receptor antagonists gallamine and pirenzepine were iontophoretically applied to rat cerebral cortical cholinoceptive neurones, including corticospinal neurones, to assess their effects on spontaneous firing, and firing induced by: stimulation of the nucleus basalis magnocellularis (NBM); contralateral hindpaw stimulation; application of acetylcholine (ACh); and application of glutamate. 2. Both compounds potently inhibited firing induced by ACh iontophoresis, whilst neither compound consistently altered firing induced by application of glutamate. 3. Gallamine was very effective and pirenzepine less effective, at inhibiting both spontaneous firing and the delayed firing induced by NBM stimulation. The short-latency excitations elicited by NBM stimulation were enhanced by these muscarinic antagonists. 4. Gallamine and pirenzepine enhanced cortical cholinoceptive cell firing induced by contralateral hindpaw stimulation. 5. It is concluded that gallamine depresses spontaneous activity more than pirenzepine, and that both compounds can affect the cortical cell firing evoked by stimulation of the NBM and of thalamo-cortical afferent fibres. PMID:3401638

  10. Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; van der Salm, Sandra M. A.; Bour, Lo J.; Edwards, Mark J.; Brown, Peter; Aronica, Eleonora; Rozemuller-Kwakkel, Johanna M.; Koehler, Peter J.; Koelman, Johannes H. T. M.; Rothwell, John C.; Tijssen, Marina A. J.

    2007-01-01

    Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar

  11. Negative Correlations in Visual Cortical Networks

    National Research Council Canada - National Science Library

    Chelaru, Mircea I; Dragoi, Valentin

    2016-01-01

    .... Whereas positive noise correlations have been extensively studied using experimental and theoretical tools, the functional role of negative correlations in cortical circuits has remained elusive...

  12. Spread spectrum time domain reflectometry

    Science.gov (United States)

    Smith, Paul Samuel

    For many years, wiring has been treated as a system that could be installed and expected to work for the life of the aircraft. As aircraft age far beyond their original expected life span, this attitude is rapidly changing. Wiring problems have recently been identified as the cause of several tragic mishaps and hundreds of thousands of lost mission hours. Intermittent wiring faults have been and continue to be difficult to resolve. Test methods that pinpoint faults on the ground can miss intermittent failures. New test methods involving spread spectrum signals are investigated that could be used in flight to locate intermittent failures, including open circuits, short circuits, and arcs. Spread spectrum time domain reflectometry (SSTDR) and sequence time domain reflectometry (STDR) are analyzed in light of the signals commonly present on aircraft wiring. Pseudo noise codes used for the generation of STDR and SSTDR signals are analyzed for application in a STDR/SSTDR test system in the presence of noise. The effects of Mil-Std 1553 and white noise on the STDR and SSTDR signals are discussed analytically, through simulations, and with the use of test hardware. A test system using STDR and SSTDR is designed, built, and used to collect STDR and SSTDR test data. The data collected with the STDR/SSTDR test hardware is analyzed and compared to the theoretical results. Experimental data for open and short circuits collected using SSTDR and a curve fitting algorithm shows a maximum range estimation error of +/-0.2 ft for 75O coaxial cable up to 100ft, and +/-0.6ft for a sample 32.5ft non-controlled impedance aircraft cable. Mil-Std 1553 is specified to operate reliably with a signal-to-noise ratio of 17.5dB, and the SSTDR test system was able to locate an open circuit on a cable also carrying simulated Mil-Std 1553 data where the SSTDR signal was 50dB below the Mil-Std 1553 signal. STDR and SSTDR are shown to be effective in detecting and locating dry and wet arcs on wires.

  13. Helping your teen with depression

    Science.gov (United States)

    Teen depression - helping; Teen depression - talk therapy; Teen depression - medicine ... teen the most. The most effective treatments for depression are: Talk therapy Antidepressant medicines If your teen ...

  14. Neurokinin-1 receptors are decreased in major depressive disorder.

    Science.gov (United States)

    Stockmeier, Craig A; Shi, Xiaochun; Konick, Lisa; Overholser, James C; Jurjus, George; Meltzer, Herbert Y; Friedman, Lee; Blier, Pierre; Rajkowska, Grazyna

    2002-07-02

    Treatment with an antagonist at the neurokinin-1 (NK-1) receptor may alleviate depression, however the brain region(s) in which the NK-1 receptor antagonist exerts its therapeutic effect is unknown. [125I]BH-Substance P was used to measure NK-1 receptors postmortem in cytoarchitectonically defined areas of rostral orbitofrontal cortex (Brodmann's area 47) of subjects with major depressive disorder (n = 12, six females) and psychiatrically normal subjects (n = 11, five females). Six subjects with depression died by suicide. Subjects with depression showed decreased binding to NK-1 receptors across all cortical layers (p = 0.024). The pathophysiology of depression, and the reported therapeutic benefit of NK-1 receptor antagonists, may thus involve NK-1 receptors in prefrontal cortex.

  15. Functional and structural brain correlates of risk for major depression in children with familial depression.

    Science.gov (United States)

    Chai, Xiaoqian J; Hirshfeld-Becker, Dina; Biederman, Joseph; Uchida, Mai; Doehrmann, Oliver; Leonard, Julia A; Salvatore, John; Kenworthy, Tara; Brown, Ariel; Kagan, Elana; de Los Angeles, Carlo; Whitfield-Gabrieli, Susan; Gabrieli, John D E

    2015-01-01

    Despite growing evidence for atypical amygdala function and structure in major depression, it remains uncertain as to whether these brain differences reflect the clinical state of depression or neurobiological traits that predispose individuals to major depression. We examined function and structure of the amygdala and associated areas in a group of unaffected children of depressed parents (at-risk group) and a group of children of parents without a history of major depression (control group). Compared to the control group, the at-risk group showed increased activation to fearful relative to neutral facial expressions in the amygdala and multiple cortical regions, and decreased activation to happy relative to neutral facial expressions in the anterior cingulate cortex and supramarginal gyrus. At-risk children also exhibited reduced amygdala volume. The extensive hyperactivation to negative facial expressions and hypoactivation to positive facial expressions in at-risk children are consistent with behavioral evidence that risk for major depression involves a bias to attend to negative information. These functional and structural brain differences between at-risk children and controls suggest that there are trait neurobiological underpinnings of risk for major depression.

  16. Functional and structural brain correlates of risk for major depression in children with familial depression

    Directory of Open Access Journals (Sweden)

    Xiaoqian J. Chai

    2015-01-01

    Full Text Available Despite growing evidence for atypical amygdala function and structure in major depression, it remains uncertain as to whether these brain differences reflect the clinical state of depression or neurobiological traits that predispose individuals to major depression. We examined function and structure of the amygdala and associated areas in a group of unaffected children of depressed parents (at-risk group and a group of children of parents without a history of major depression (control group. Compared to the control group, the at-risk group showed increased activation to fearful relative to neutral facial expressions in the amygdala and multiple cortical regions, and decreased activation to happy relative to neutral facial expressions in the anterior cingulate cortex and supramarginal gyrus. At-risk children also exhibited reduced amygdala volume. The extensive hyperactivation to negative facial expressions and hypoactivation to positive facial expressions in at-risk children are consistent with behavioral evidence that risk for major depression involves a bias to attend to negative information. These functional and structural brain differences between at-risk children and controls suggest that there are trait neurobiological underpinnings of risk for major depression.

  17. Do Studies on Cortical Plasticity Provide a Rationale for Using Non-Invasive Brain Stimulation as a Treatment for Parkinson’s Disease Patients?

    OpenAIRE

    Koch, Giacomo

    2013-01-01

    Animal models of Parkinson’s disease (PD) have shown that key mechanisms of cortical plasticity such as long-term potentiation (LTP) and long-term depression (LTD) can be impaired by the PD pathology. In humans protocols of non-invasive brain stimulation, such as paired associative stimulation (PAS) and theta-burst stimulation (TBS), can be used to investigate cortical plasticity of the primary motor cortex. Through the amplitude of the motor evoked potential these transcranial magnetic stimu...

  18. Impacts of suppressing guide on information spreading

    CERN Document Server

    Xu, Jinghong; Ma, Baojun; Wu, Ye

    2015-01-01

    It is quite common that guides are introduced to suppress the information spreading in modern society for different purposes. In this paper, an agent-based model is established to quantitatively analyze the impacts of suppressing guides on information spreading. We find that the spreading threshold depends on the attractiveness of the information and the topology of the social network with no suppressing guides at all. Usually, one would expect that the existence of suppressing guides in the spreading procedure may result in less diffusion of information within the overall network. However, we find that sometimes the opposite is true: the manipulating nodes of suppressing guides may lead to more extensive information spreading when there are audiences with the reversal mind. These results can provide valuable theoretical references to public opinion guidance on various information, e.g., rumor or news spreading.

  19. Impacts of suppressing guide on information spreading

    Science.gov (United States)

    Xu, Jinghong; Zhang, Lin; Ma, Baojun; Wu, Ye

    2016-02-01

    It is quite common that guides are introduced to suppress the information spreading in modern society for different purposes. In this paper, an agent-based model is established to quantitatively analyze the impacts of suppressing guides on information spreading. We find that the spreading threshold depends on the attractiveness of the information and the topology of the social network with no suppressing guides at all. Usually, one would expect that the existence of suppressing guides in the spreading procedure may result in less diffusion of information within the overall network. However, we find that sometimes the opposite is true: the manipulating nodes of suppressing guides may lead to more extensive information spreading when there are audiences with the reversal mind. These results can provide valuable theoretical references to public opinion guidance on various information, e.g., rumor or news spreading.

  20. Gyrification from constrained cortical expansion

    CERN Document Server

    Tallinen, Tuomas; Biggins, John S; Mahadevan, L

    2015-01-01

    The exterior of the mammalian brain - the cerebral cortex - has a conserved layered structure whose thickness varies little across species. However, selection pressures over evolutionary time scales have led to cortices that have a large surface area to volume ratio in some organisms, with the result that the brain is strongly convoluted into sulci and gyri. Here we show that the gyrification can arise as a nonlinear consequence of a simple mechanical instability driven by tangential expansion of the gray matter constrained by the white matter. A physical mimic of the process using a layered swelling gel captures the essence of the mechanism, and numerical simulations of the brain treated as a soft solid lead to the formation of cusped sulci and smooth gyri similar to those in the brain. The resulting gyrification patterns are a function of relative cortical expansion and relative thickness (compared with brain size), and are consistent with observations of a wide range of brains, ranging from smooth to highl...

  1. Cortical control of facial expression.

    Science.gov (United States)

    Müri, René M

    2016-06-01

    The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.

  2. A general method for identifying node spreading influence via the adjacent matrix and spreading rate

    CERN Document Server

    Lin, Jian-Hong; Guo, Qiang

    2014-01-01

    With great theoretical and practical significance, identifying the node spreading influence of complex network is one of the most promising domains. So far, various topology-based centrality measures have been proposed to identify the node spreading influence in a network. However, the node spreading influence is a result of the interplay between the network topology structure and spreading dynamics. In this paper, we build up the systematic method by combining the network structure and spreading dynamics to identify the node spreading influence. By combining the adjacent matrix $A$ and spreading parameter $\\beta$, we theoretical give the node spreading influence with the eigenvector of the largest eigenvalue. Comparing with the Susceptible-Infected-Recovered (SIR) model epidemic results for four real networks, our method could identify the node spreading influence more accurately than the ones generated by the degree, K-shell and eigenvector centrality. This work may provide a systematic method for identifyi...

  3. Equatorial spread F fossil plumes

    Directory of Open Access Journals (Sweden)

    S. L. Ossakow

    2010-11-01

    Full Text Available Behaviour of equatorial spread F (ESF fossil plumes, i.e., ESF plumes that have stopped rising, is examined using the NRL SAMI3/ESF three-dimensional simulation code. We find that fossil bubbles, plasma density depletions associated with fossil plumes, can persist as high-altitude equatorial depletions even while being "blown" by zonal winds. Corresponding airglow-proxy images of fossil plumes, plots of electron density versus longitude and latitude at a constant altitude of 288 km, are shown to partially "fill in" in most cases, beginning with the highest altitude field lines within the plume. Specifically, field lines upon which the E field has fallen entirely to zero are affected and only the low altitude (≤600 km portion if each field line fills in. This suggests that it should be possible to observe a bubble at high altitude on a field line for which the corresponding airglow image no longer shows a depletion. In all cases ESF plumes stop rising when the flux-tube-integrated ion mass density inside the upper edge of the bubble is equal to that of the nearby background, further supporting the result of Krall et al. (2010b.

  4. Drops spreading on flexible fibers

    Science.gov (United States)

    Somszor, Katarzyna; Boulogne, François; Sauret, Alban; Dressaire, Emilie; Stone, Howard

    2015-11-01

    Fibrous media are encountered in many engineered systems such as textile, paper and insulating materials. In most of these materials, fibers are randomly oriented and form a complex network in which drops of wetting liquid tend to accumulate at the nodes of the network. Here we investigate the role of the fiber flexibility on the spreading of a small volume of liquid on a pair of crossed flexible fibers. A drop of silicone oil is dispensed at the point of contact of the fibers and we characterize the liquid morphologies as we vary the volume of liquid, the angle between the fibers, and the length and bending modulus of the fibers. Drop morphologies previously reported for rigid fibers, i.e. a drop, a column and a mixed morphology, are also observed on flexible fibers with modified domains of existence. Moreover, at small inclination angles of the fibers, a new behavior is observed: the fibers bend and collapse. Depending on the volume, the liquid can adopt a column or a mixed morphology on the collapsed fibers. We rationalize our observations with a model based on energetic considerations. Our study suggests that the fiber flexibility adds a rich variety of behaviors that can be crucial for industrial applications.

  5. Information Spreading in Dynamic Graphs

    CERN Document Server

    Clementi, Andrea; Trevisan, Luca

    2011-01-01

    We present a general approach to study the flooding time (a measure of how fast information spreads) in dynamic graphs (graphs whose topology changes with time according to a random process). We consider arbitrary converging Markovian dynamic graph process, that is, processes in which the topology of the graph at time $t$ depends only on its topology at time $t-1$ and which have a unique stationary distribution. The most well studied models of dynamic graphs are all Markovian and converging. Under general conditions, we bound the flooding time in terms of the mixing time of the dynamic graph process. We recover, as special cases of our result, bounds on the flooding time for the \\emph{random trip} model and the \\emph{random path} models; previous analysis techniques provided bounds only in restricted settings for such models. Our result also provides the first bound for the \\emph{random waypoint} model (which is tight for certain ranges of parameters) whose analysis had been an important open question.

  6. Dynamical model for virus spread

    CERN Document Server

    Camelo-Neto, G

    1995-01-01

    The steady state properties of the mean density population of infected cells in a viral spread is simulated by a general forest fire like cellular automaton model with two distinct populations of cells ( permissive and resistant ones) and studied in the framework of the mean field approximation. Stochastic dynamical ingredients are introduced in this model to mimic cells regeneration (with probability {\\it p}) and to consider infection processes by other means than contiguity (with probability {\\it f}). Simulations are carried on a L \\times L square lattice considering the eight first neighbors. The mean density population of infected cells (D_i) is measured as function of the regeneration probability {\\it p}, and analyzed for small values of the ratio {\\it f/p } and for distinct degrees of the cell resistance. The results obtained by a mean field like approach recovers the simulations results. The role of the resistant parameter R (R \\geq 2) on the steady state properties is investigated and discussed in com...

  7. What Drives the POLONIA Spread in Poland?

    OpenAIRE

    Yinqiu Lu

    2012-01-01

    Since the start of the 2008 - 09 financial crisis, the Polish Overnight Index Average (POLONIA) has persistently been below the policy rate, suggesting a limited influence of the NBP’s open market operations on the short-term interbank rate. In this regard, this paper analyzes the behavior of the POLONIA spread and explore several potential factors that could influence the spread. An empirical analysis confirms that the negative POLONIA spread is related to a few factors, which include the ...

  8. Information spreading and development of cultural centers

    CERN Document Server

    Dybiec, Bartlomiej; Sneppen, Kim

    2012-01-01

    The historical interplay between societies are governed by many factors, including in particular spreading of languages, religion and other symbolic traits. Cultural development, in turn, is coupled to emergence and maintenance of information spreading. Strong centralized cultures exist thanks to attention from their members, which faithfulness in turn relies on supply of information. Here, we discuss a culture evolution model on a planar geometry that takes into account aspects of the feedback between information spreading and its maintenance. Features of model are highlighted by comparing it to cultural spreading in ancient and medieval Europe, where it in particular suggests that long lived centers should be located in geographically remote regions.

  9. Credit Spreads Across the Business Cycle

    DEFF Research Database (Denmark)

    Nielsen, Mads Stenbo

    This paper studies how corporate bond spreads vary with the business cycle. I show that both level and slope of empirical credit spread curves are correlated with the state of the economy, and I link this to variation in idiosyncratic jump risk. I develop a structural credit risk model that accou......This paper studies how corporate bond spreads vary with the business cycle. I show that both level and slope of empirical credit spread curves are correlated with the state of the economy, and I link this to variation in idiosyncratic jump risk. I develop a structural credit risk model...... to firm fundamentals....

  10. Integrated mechanisms of anticipation and rate-of-change computations in cortical circuits.

    Science.gov (United States)

    Puccini, Gabriel D; Sanchez-Vives, Maria V; Compte, Albert

    2007-05-01

    Local neocortical circuits are characterized by stereotypical physiological and structural features that subserve generic computational operations. These basic computations of the cortical microcircuit emerge through the interplay of neuronal connectivity, cellular intrinsic properties, and synaptic plasticity dynamics. How these interacting mechanisms generate specific computational operations in the cortical circuit remains largely unknown. Here, we identify the neurophysiological basis of both the rate of change and anticipation computations on synaptic inputs in a cortical circuit. Through biophysically realistic computer simulations and neuronal recordings, we show that the rate-of-change computation is operated robustly in cortical networks through the combination of two ubiquitous brain mechanisms: short-term synaptic depression and spike-frequency adaptation. We then show how this rate-of-change circuit can be embedded in a convergently connected network to anticipate temporally incoming synaptic inputs, in quantitative agreement with experimental findings on anticipatory responses to moving stimuli in the primary visual cortex. Given the robustness of the mechanism and the widespread nature of the physiological machinery involved, we suggest that rate-of-change computation and temporal anticipation are principal, hard-wired functions of neural information processing in the cortical microcircuit.

  11. Integrated mechanisms of anticipation and rate-of-change computations in cortical circuits.

    Directory of Open Access Journals (Sweden)

    Gabriel D Puccini

    2007-05-01

    Full Text Available Local neocortical circuits are characterized by stereotypical physiological and structural features that subserve generic computational operations. These basic computations of the cortical microcircuit emerge through the interplay of neuronal connectivity, cellular intrinsic properties, and synaptic plasticity dynamics. How these interacting mechanisms generate specific computational operations in the cortical circuit remains largely unknown. Here, we identify the neurophysiological basis of both the rate of change and anticipation computations on synaptic inputs in a cortical circuit. Through biophysically realistic computer simulations and neuronal recordings, we show that the rate-of-change computation is operated robustly in cortical networks through the combination of two ubiquitous brain mechanisms: short-term synaptic depression and spike-frequency adaptation. We then show how this rate-of-change circuit can be embedded in a convergently connected network to anticipate temporally incoming synaptic inputs, in quantitative agreement with experimental findings on anticipatory responses to moving stimuli in the primary visual cortex. Given the robustness of the mechanism and the widespread nature of the physiological machinery involved, we suggest that rate-of-change computation and temporal anticipation are principal, hard-wired functions of neural information processing in the cortical microcircuit.

  12. Response of Quiescent Cerebral Cortical Astrocytes to Nanofibrillar Scaffold Properties

    Science.gov (United States)

    Ayres, Virginia; Mujdat Tiryaki, Volkan; Xie, Kan; Ahmed, Ijaz; Shreiber, David I.

    2013-03-01

    We present results of an investigation to examine the hypothesis that the extracellular environment can trigger specific signaling cascades with morphological consequences. Differences in the morphological responses of quiescent cerebral cortical astrocytes cultured on the nanofibrillar matrices versus poly-L-lysine functionalized glass and Aclar, and unfunctionalized Aclar surfaces were demonstrated using atomic force microscopy (AFM) and phalloidin staining of F-actin. The differences and similarities of the morphological responses were consistent with differences and similarities of the surface polarity and surface roughness of the four surfaces investigated in this work, characterized using contact angle and AFM measurements. The three-dimensional capability of AFM was also used to identify differences in cell spreading. An initial quantitative immunolabeling study further identified significant differences in the activation of the Rho GTPases: Cdc42, Rac1, and RhoA, which are upstream regulators of the observed morphological responses: filopodia, lamellipodia, and stress fiber formation. The results support the hypothesis that the extracellular environment can trigger preferential activation of members of the Rho GTPase family with demonstrable morphological consequences for cerebral cortical astrocytes. The support of NSF PHY-095776 is acknowledged.

  13. Olive oil in food spreads

    Directory of Open Access Journals (Sweden)

    Blanco Muñoz, Miguel A.

    2004-03-01

    Full Text Available Chemical hydrogenation of unsaturated fatty acids is a commonly applied reaction to food industries. The process may imply the movement of double bonds in their positions on the fatty acid carbon chain, producing positional and geometrical isomers ( trans fatty acids. Through hydrogenation, unsaturated oils are converted to margarines and vegetable shortenings. The presence of trans fatty acids in foods is undesirable, as trans fatty acids raise the plasma levels of total and low-density lipoproteins (LDL, while decrease the plasma level of high-density lipoproteins (HDL, among other effects. The use of olive oil to prepare fat spread opens new insights into the commercial development of healthy novel foods with a positive image in terms of consumer appeal.La hidrogenación química de los ácidos grasos insaturados es una reacción que se utiliza con frecuencia en la industria alimentaria. El proceso implica el movimiento de los dobles enlaces en la cadena hidrocarbonada de los ácidos grasos, y la aparición de isómeros posicionales y geométricos (ácidos grasos trans . La ingesta inadecuada de alimentos que pueden contener cantidades significativas de ácidos grasos trans se asocia con el aumento en sangre de colesterol total y LDL, y la disminución de HDL, entre otros efectos. Por lo tanto, el uso de aceite de oliva en la preparación de grasas para untar constituye un importante avance en el desarrollo comercial de nuevos alimentos saludables con una imagen positiva para el consumidor.

  14. What is depression?

    DEFF Research Database (Denmark)

    Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

    2014-01-01

    The diagnosis of depression is defined by psychiatrists, and guidelines for treatment of patients with depression are created in psychiatry. However, most patients with depression are treated exclusively in general practice. Psychiatrists point out that general practitioners' (GPs') treatment of ...

  15. Sadness and Depression

    Science.gov (United States)

    ... What Happens in the Operating Room? Sadness and Depression KidsHealth > For Kids > Sadness and Depression A A ... big difference in your life. When Sadness Is Depression When you're in a sad mood, it ...

  16. Depression Strikes…Anyone

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Depression Depression Strikes… Anyone Winter 2017 Table of Contents Anyone can suffer from depression. And almost everyone has a friend or family ...

  17. Depression and College Students

    Science.gov (United States)

    ... depression and other mental health issues? Reference Share Depression and College Students Download PDF Download ePub Order ... Answers to college students’ frequently asked questions about depression Feeling moody, sad, or grouchy? Who doesn’t ...

  18. Sadness and Depression

    Science.gov (United States)

    ... dientes Video: Getting an X-ray Sadness and Depression KidsHealth > For Kids > Sadness and Depression Print A ... big difference in your life. When Sadness Is Depression When you're in a sad mood, it ...

  19. Postpartum Depression Facts

    Science.gov (United States)

    ... Where can I find more information? Share Postpartum Depression Facts Download PDF Download ePub Download Mobi Order ... for herself or her family. What is postpartum depression? Postpartum depression is a mood disorder that can ...

  20. Recognizing teen depression

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000648.htm Recognizing teen depression To use the sharing features on this page, ... life. Be Aware of the Risk for Teen Depression Your teen is more at risk for depression ...

  1. Men and Depression

    Science.gov (United States)

    ... in crisis? For more information Share Men and Depression Download PDF Download ePub Order a free hardcopy ... If so, you may have depression. What is depression? Everyone feels sad or irritable sometimes, or has ...

  2. Various forms of depression

    OpenAIRE

    BENAZZI, FRANCO

    2006-01-01

    The current subtyping of depression is based on the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Text Revision (DSM-IV-TR) categorical division of bipolar and depressive disorders. Current evidence, however, supports a dimensional approach to depression, as a continuum/spectrum of overlapping disorders, ranging from bipolar I depression to major depressive disorder. Types of depression which have recently been the focus of most research will be reviewed ; bipolar II depressi...

  3. [Depressive symptoms and sexuality].

    Science.gov (United States)

    Porto, Robert

    2014-10-01

    The mutually reinforcing dyad of depressive symptoms and erectile dysfunction is scientifically established. The cure of depression improves sexual dysfunction (SD) and the treatment of SD induces improvement of depression. Most of anti-depressants induce negative sexual side effects that lead to non-compliance of these treatments. The knowledge of interrelation between depression, anti-depressants and sexuality is of great importance in clinical practice. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Inverted-U Function Relating Cortical Plasticity and Task Difficulty

    Science.gov (United States)

    Engineer, Navzer D.; Engineer, Crystal T.; Reed, Amanda C.; Pandya, Pritesh K.; Jakkamsetti, Vikram; Moucha, Raluca; Kilgard, Michael P.

    2012-01-01

    Many psychological and physiological studies with simple stimuli have suggested that perceptual learning specifically enhances the response of primary sensory cortex to task-relevant stimuli. The aim of this study was to determine whether auditory discrimination training on complex tasks enhances primary auditory cortex responses to a target sequence relative to non-target and novel sequences. We collected responses from more than 2,000 sites in 31 rats trained on one of six discrimination tasks that differed primarily in the similarity of the target and distractor sequences. Unlike training with simple stimuli, long-term training with complex stimuli did not generate target specific enhancement in any of the groups. Instead, cortical receptive field size decreased, latency decreased, and paired pulse depression decreased in rats trained on the tasks of intermediate difficulty while tasks that were too easy or too difficult either did not alter or degraded cortical responses. These results suggest an inverted-U function relating neural plasticity and task difficulty. PMID:22249158

  5. Cortical control of whisker movement.

    Science.gov (United States)

    Petersen, Carl C H

    2014-01-01

    Facial muscles drive whisker movements, which are important for active tactile sensory perception in mice and rats. These whisker muscles are innervated by cholinergic motor neurons located in the lateral facial nucleus. The whisker motor neurons receive synaptic inputs from premotor neurons, which are located within the brain stem, the midbrain, and the neocortex. Complex, distributed neural circuits therefore regulate whisker movement during behavior. This review focuses specifically on cortical whisker motor control. The whisker primary motor cortex (M1) strongly innervates brain stem reticular nuclei containing whisker premotor neurons, which might form a central pattern generator for rhythmic whisker protraction. In a parallel analogous pathway, the whisker primary somatosensory cortex (S1) strongly projects to the brain stem spinal trigeminal interpolaris nucleus, which contains whisker premotor neurons innervating muscles for whisker retraction. These anatomical pathways may play important functional roles, since stimulation of M1 drives exploratory rhythmic whisking, whereas stimulation of S1 drives whisker retraction.

  6. The origin of cortical neurons

    Directory of Open Access Journals (Sweden)

    J.G. Parnavelas

    2002-12-01

    Full Text Available Neurons of the mammalian cerebral cortex comprise two broad classes: pyramidal neurons, which project to distant targets, and the inhibitory nonpyramidal cells, the cortical interneurons. Pyramidal neurons are generated in the germinal ventricular zone, which lines the lateral ventricles, and migrate along the processes of radial glial cells to their positions in the developing cortex in an `inside-out' sequence. The GABA-containing nonpyramidal cells originate for the most part in the ganglionic eminence, the primordium of the basal ganglia in the ventral telencephalon. These cells follow tangential migratory routes to enter the cortex and are in close association with the corticofugal axonal system. Once they enter the cortex, they move towards the ventricular zone, possibly to obtain positional information, before they migrate radially in the direction of the pial surface to take up their positions in the developing cortex. The mechanisms that guide interneurons throughout these long and complex migratory routes are currently under investigation.

  7. Cortical cartography and Caret software.

    Science.gov (United States)

    Van Essen, David C

    2012-08-15

    Caret software is widely used for analyzing and visualizing many types of fMRI data, often in conjunction with experimental data from other modalities. This article places Caret's development in a historical context that spans three decades of brain mapping--from the early days of manually generated flat maps to the nascent field of human connectomics. It also highlights some of Caret's distinctive capabilities. This includes the ease of visualizing data on surfaces and/or volumes and on atlases as well as individual subjects. Caret can display many types of experimental data using various combinations of overlays (e.g., fMRI activation maps, cortical parcellations, areal boundaries), and it has other features that facilitate the analysis and visualization of complex neuroimaging datasets. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Age, spreading rates, and spreading asymmetry of the world's ocean crust

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The authors present four companion digital models of the age, age uncertainty, spreading rates and spreading asymmetries of the world's ocean basins as geographic...

  9. Unsupervised fetal cortical surface parcellation

    Science.gov (United States)

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-03-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features.

  10. Modelling unidirectional liquid spreading on slanted microposts

    DEFF Research Database (Denmark)

    Cavalli, Andrea; Blow, Matthew L.; Yeomans, Julia M.

    2013-01-01

    A lattice Boltzmann algorithm is used to simulate the slow spreading of drops on a surface patterned with slanted micro-posts. Gibb's pinning of the interface on the sides or top of the posts leads to unidirectional spreading over a wide range of contact angles and inclination angles of the posts...

  11. Spreading to localized targets in complex networks

    Science.gov (United States)

    Sun, Ye; Ma, Long; Zeng, An; Wang, Wen-Xu

    2016-12-01

    As an important type of dynamics on complex networks, spreading is widely used to model many real processes such as the epidemic contagion and information propagation. One of the most significant research questions in spreading is to rank the spreading ability of nodes in the network. To this end, substantial effort has been made and a variety of effective methods have been proposed. These methods usually define the spreading ability of a node as the number of finally infected nodes given that the spreading is initialized from the node. However, in many real cases such as advertising and news propagation, the spreading only aims to cover a specific group of nodes. Therefore, it is necessary to study the spreading ability of nodes towards localized targets in complex networks. In this paper, we propose a reversed local path algorithm for this problem. Simulation results show that our method outperforms the existing methods in identifying the influential nodes with respect to these localized targets. Moreover, the influential spreaders identified by our method can effectively avoid infecting the non-target nodes in the spreading process.

  12. The Imaging of Large Nerve Perineural Spread.

    Science.gov (United States)

    Gandhi, Mitesh; Sommerville, Jennifer

    2016-04-01

    We present a review of the imaging findings of large nerve perineural spread within the skull base. The MRI techniques and reasons for performing different sequences are discussed. A series of imaging examples illustrates the appearance of perineural tumor spread with an emphasis on the zonal staging system.

  13. Fire spread characteristics determined in the laboratory

    Science.gov (United States)

    Richard C. Rothermel; Hal E. Anderson

    1966-01-01

    Fuel beds of ponderosa pine needles and white pine needles were burned under controlled environmental conditions to determine the effects of fuel moisture and windspeed upon the rate of fire spread. Empirical formulas are presented to show the effect of these parameters. A discussion of rate of spread and some simple experiments show how fuel may be preheated before...

  14. Towards a 'canonical' agranular cortical microcircuit

    Directory of Open Access Journals (Sweden)

    Sarah F. Beul

    2015-01-01

    Full Text Available Based on regularities in the intrinsic microcircuitry of cortical areas, variants of a 'canonical' cortical microcircuit have been proposed and widely adopted, particularly in computational neuroscience and neuroinformatics. However, this circuit is founded on striate cortex, which manifests perhaps the most extreme instance of cortical organization, in terms of a very high density of cells in highly differentiated cortical layers. Most other cortical regions have a less well differentiated architecture, stretching in gradients from the very dense eulaminate primary cortical areas to the other extreme of dysgranular and agranular areas of low density and poor laminar differentiation. It is unlikely for the patterns of inter- and intra-laminar connections to be uniform in spite of strong variations of their structural substrate. This assumption is corroborated by reports of divergence in intrinsic circuitry across the cortex. Consequently, it remains an important goal to define local microcircuits for a variety of cortical types, in particular, agranular cortical regions. As a counterpoint to the striate microcircuit, which may be anchored in an exceptional cytoarchitecture, we here outline a tentative microcircuit for agranular cortex. The circuit is based on a synthesis of the available literature on the local microcircuitry in agranular cortical areas of the rodent brain, investigated by anatomical and electrophysiological approaches. A central observation of these investigations is a weakening of interlaminar inhibition as cortical cytoarchitecture becomes less distinctive. Thus, our study of agranular microcircuitry revealed deviations from the well-known 'canonical' microcircuit established for striate cortex, suggesting variations in the intrinsic circuitry across the cortex that may be functionally relevant.

  15. Spreading Modes on Copper and Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Feoktistov Dmitry

    2016-01-01

    Full Text Available This work presents the experimental results of the studying the effect of surface roughness, microstructure and liquid flow rate on the dynamic contact angle during spreading of distilled nondeaerated water drop on a solid horizontal substrate. Copper and steel substrates with different roughness have been investigated. Three spreading modes were conventionally indicated. It was found that the spreading of drops on substrates made of different materials occurs in similar modes. However, the duration of each mode for substrates made of copper and steel are different. Spreading of a liquid above the asperities of a surface micro relief was observed to be dominant for large volumetric flow rates of drops (0.01 ml/s. Liquid was spreading inside the grooves of a rough substrate at low rates (0.005 ml/s.

  16. Information spreading on dynamic social networks

    CERN Document Server

    Liu, Chuang

    2012-01-01

    Nowadays, information spreading on social networks has triggered an explosive attention in various disciplines. Most of previous related works in this area mainly focus on discussing the effects of spreading probability or immunization strategy on static networks. However, in real systems, the peer-to-peer network structure changes constantly according to frequently social activities of users. In order to capture this dynamical property and study its impact on information spreading, in this Letter, a link rewiring strategy based on the Fermi function is introduced. In the present model, the informed individuals tend to break old links and reconnect to ones with more uninformed neighbors. Simulation results on the susceptible-infected (\\textit{SI}) model with non-redundancy contacts indicate that the information spread more faster and broader with the rewiring strategy. Extensive analyses of the information cascading show that the spreading process of the initial steps plays a very important role, that is to s...

  17. Enhanced droplet spreading due to thermal fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Willis, A M; Freund, J B, E-mail: jbfreund@illinois.ed [Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)

    2009-11-18

    The lubrication equation that governs the dynamics of thin liquid films can be augmented to account for stochastic stresses associated with the thermal fluctuations of the fluid. It has been suggested that under certain conditions the spreading rate of a liquid drop on a surface will be increased by these stochastic stresses. Here, an atomistic simulation of a spreading drop is designed to examine such a regime and provide a quantitative assessment of the stochastic lubrication equation for spreading. It is found that the atomistic drop does indeed spread faster than the standard lubrication equations would suggest and that the stochastic lubrication equation of Gruen et al (2006 J. Stat. Phys. 122 1261-91) predicts the spread rate.

  18. Interpolating point spread function anisotropy

    Science.gov (United States)

    Gentile, M.; Courbin, F.; Meylan, G.

    2013-01-01

    Planned wide-field weak lensing surveys are expected to reduce the statistical errors on the shear field to unprecedented levels. In contrast, systematic errors like those induced by the convolution with the point spread function (PSF) will not benefit from that scaling effect and will require very accurate modeling and correction. While numerous methods have been devised to carry out the PSF correction itself, modeling of the PSF shape and its spatial variations across the instrument field of view has, so far, attracted much less attention. This step is nevertheless crucial because the PSF is only known at star positions while the correction has to be performed at any position on the sky. A reliable interpolation scheme is therefore mandatory and a popular approach has been to use low-order bivariate polynomials. In the present paper, we evaluate four other classical spatial interpolation methods based on splines (B-splines), inverse distance weighting (IDW), radial basis functions (RBF) and ordinary Kriging (OK). These methods are tested on the Star-challenge part of the GRavitational lEnsing Accuracy Testing 2010 (GREAT10) simulated data and are compared with the classical polynomial fitting (Polyfit). In all our methods we model the PSF using a single Moffat profile and we interpolate the fitted parameters at a set of required positions. This allowed us to win the Star-challenge of GREAT10, with the B-splines method. However, we also test all our interpolation methods independently of the way the PSF is modeled, by interpolating the GREAT10 star fields themselves (i.e., the PSF parameters are known exactly at star positions). We find in that case RBF to be the clear winner, closely followed by the other local methods, IDW and OK. The global methods, Polyfit and B-splines, are largely behind, especially in fields with (ground-based) turbulent PSFs. In fields with non-turbulent PSFs, all interpolators reach a variance on PSF systematics σ2sys better than the 1

  19. Organisation of Xenopus oocyte and egg cortices.

    Science.gov (United States)

    Chang, P; Pérez-Mongiovi, D; Houliston, E

    1999-03-15

    The division of the Xenopus oocyte cortex into structurally and functionally distinct "animal" and "vegetal" regions during oogenesis provides the basis of the organisation of the early embryo. The vegetal region of the cortex accumulates specific maternal mRNAs that specify the development of the endoderm and mesoderm, as well as functionally-defined "determinants" of dorso-anterior development, and recognisable "germ plasm" determinants that segregate into primary germ cells. These localised elements on the vegetal cortex underlie both the primary animal-vegetal polarity of the egg and the organisation of the developing embryo. The animal cortex meanwhile becomes specialised for the events associated with fertilisation: sperm entry, calcium release into the cytoplasm, cortical granule exocytosis, and polarised cortical contraction. Cortical and subcortical reorganisations associated with meiotic maturation, fertilisation, cortical rotation, and the first mitotic cleavage divisions redistribute the vegetal cortical determinants, contributing to the specification of dorso-anterior axis and segregation of the germ line. In this article we consider what is known about the changing organisation of the oocyte and egg cortex in relation to the mechanisms of determinant localisation, anchorage, and redistribution, and show novel ultrastructural views of cortices isolated at different stages and processed by the rapid-freeze deep-etch method. Cortical organisation involves interactions between the different cytoskeletal filament systems and internal membranes. Associated proteins and cytoplasmic signals probably modulate these interactions in stage-specific ways, leaving much to be understood.

  20. Somatosensory Misrepresentation Associated with Chronic Pain: Spatiotemporal Correlates of Sensory Perception in a Patient following a Complex Regional Pain Syndrome Spread.

    Science.gov (United States)

    Büntjen, Lars; Hopf, Jens-Max; Merkel, Christian; Voges, Jürgen; Knape, Stefan; Heinze, Hans-Jochen; Schoenfeld, Mircea Ariel

    2017-01-01

    Chronic pain is suggested to be linked to reorganization processes in the sensorimotor cortex. In the current study, the somatosensory representation of the extremities was investigated in a patient with a complex regional pain syndrome (CRPS) that initially occurred in the right hand and arm and spread later into the left hand and right leg. After the spread, magnetoencephalographic recordings in conjunction with somatosensory stimulation revealed that the clinical symptoms were associated with major changes in the primary somatosensory representation. Tactile stimulation of body parts triggering CRPS-related pain elicited activity located in the left primary somatosensory region corresponding to the right hand representation, where the CRPS initially appeared. Solely the unaffected left foot was observed to have a regular S1 representation. The pain distribution pattern was matching the cortical somatosensory misrepresentation suggesting that cortical reorganization processes might contribute and possibly underlie the development and spread of the CRPS.

  1. Development of Pistachio (Pistacia vera L.) spread.

    Science.gov (United States)

    Shakerardekani, Ahmad; Karim, Roselina; Ghazali, Hasanah Mohd; Chin, Nyuk Ling

    2013-03-01

    Pistachio nut (Pistacia vera L.) is one of the most delicious and nutritious nuts in the world. Pistachio spreads were developed using pistachio paste as the main component, icing sugar, soy protein isolate (SPI), and red palm oil (RPO), at different ratios. The highest mean scores of all the sensory attributes were depicted by spreads that were made without addition of SPI. It was found that the work of shear was 0 to 11.0 kg s for an acceptable spread. Sensory spreadability, overall texture, spreadability, and overall acceptability were negatively correlated (R > 0.83) with the work of shear of spreads. The findings indicated that the presence of RPO had a direct effect on the viscoelastic behavior of the pistachio spreads. The a values, which are related to the green color of the pistachio product ranged from 1.7 to 3.9 for spread without addition of RPO, and 4.0 to 5.3 in the presence of RPO. The development of pistachio spread would potentially increase the food uses of pistachio and introduce consumers with a healthier snack food. © 2013 Institute of Food Technologists®

  2. Contrast-induced transient cortical blindness.

    Science.gov (United States)

    Shah, Parth R; Yohendran, Jayshan; Parker, Geoffrey D; McCluskey, Peter J

    2013-05-01

    We present a case of transient cortical blindness secondary to contrast medium toxicity. A 58-year-old man had successful endovascular coiling of a right posterior inferior cerebellar artery aneurysm but became confused and unable to see after the procedure. His visual acuity was no light perception bilaterally. Clinically, there was no new intra-ocular pathology. An urgent non-contrast computed tomography scan of the brain showed cortical hyperdensity in both parieto-occipital cortices, consistent with contrast medium leakage through the blood-brain barrier from the coiling procedure. The man remained completely blind for 72 hours, after which his visual acuity improved gradually back to his baseline level.

  3. Reversible cortical blindness: posterior reversible encephalopathy syndrome.

    Science.gov (United States)

    Bandyopadhyay, Sabyasachi; Mondal, Kanchan Kumar; Das, Somnath; Gupta, Anindya; Biswas, Jaya; Bhattacharyya, Subir Kumar; Biswas, Gautam

    2010-11-01

    Cortical blindness is defined as visual failure with preserved pupillary reflexes in structurally intact eyes due to bilateral lesions affecting occipital cortex. Bilateral oedema and infarction of the posterior and middle cerebral arterial territory, trauma, glioma and meningioma of the occipital cortex are the main causes of cortical blindness. Posterior reversible encephalopathy syndrome (PRES) refers to the reversible subtype of cortical blindness and is usually associated with hypertension, diabetes, immunosuppression, puerperium with or without eclampsia. Here, 3 cases of PRES with complete or partial visual recovery following treatment in 6-month follow-up are reported.

  4. Tibial cortical lesions: A multimodality pictorial review

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, P.A., E-mail: philippa.tyler@rnoh.nhs.uk [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Mohaghegh, P., E-mail: pegah1000@gmail.com [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Foley, J., E-mail: jfoley1@nhs.net [Department of Radiology, Glasgow Royal Infirmary, 16 Alexandra Parade, Glasgow G31 2ES (United Kingdom); Isaac, A., E-mail: amandaisaac@doctors.org.uk [Department of Radiology, King' s College Hospital, Denmark Hill, London SE5 9RS (United Kingdom); Zavareh, A., E-mail: ali.zavareh@gmail.com [Department of Radiology, North Bristol NHS Trust, Frenchay, Bristol BS16 1LE (United Kingdom); Thorning, C., E-mail: cthorning@doctors.org.uk [Department of Radiology, East Surrey Hospital, Canada Avenue, Redhill, Surrey RH1 5RH (United Kingdom); Kirwadi, A., E-mail: anandkirwadi@gmail.com [Department of Radiology, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL (United Kingdom); Pressney, I., E-mail: ipressney@hotmail.com [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Amary, F., E-mail: fernanda.amary@rnoh.nhs.uk [Department of Histopathology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Rajeswaran, G., E-mail: grajeswaran@gmail.com [Department of Radiology, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH (United Kingdom)

    2015-01-15

    Highlights: • Multimodality imaging plays an important role in the investigation and diagnosis of shin pain. • We review the multimodality imaging findings of common cortically based tibial lesions. • We also describe the rarer pathologies of tibial cortical lesions. - Abstract: Shin pain is a common complaint, particularly in young and active patients, with a wide range of potential diagnoses and resulting implications. We review the natural history and multimodality imaging findings of the more common causes of cortically-based tibial lesions, as well as the rarer pathologies less frequently encountered in a general radiology department.

  5. Spread polynomials, rotations and the butterfly effect

    CERN Document Server

    Goh, Shuxiang

    2009-01-01

    The spread between two lines in rational trigonometry replaces the concept of angle, allowing the complete specification of many geometrical and dynamical situations which have traditionally been viewed approximately. This paper investigates the case of powers of a rational spread rotation, and in particular, a curious periodicity in the prime power decomposition of the associated values of the spread polynomials, which are the analogs in rational trigonometry of the Chebyshev polynomials of the first kind. Rational trigonometry over finite fields plays a role, together with non-Euclidean geometries.

  6. Pulsations, interpulsations, and sea-floor spreading.

    Science.gov (United States)

    Pessagno, E. A., Jr.

    1973-01-01

    It is postulated that worldwide transgressions (pulsations) and regressions (interpulsations) through the course of geologic time are related to the elevation and subsidence of oceanic ridge systems and to sea-floor spreading. Two multiple working hypotheses are advanced to explain major transgressions and regressions and the elevation and subsidence of oceanic ridge systems. One hypothesis interrelates the sea-floor spreading hypothesis to the hypothesis of sub-Mohorovicic serpentinization. The second hypothesis relates the sea-floor spreading hypothesis to a hypothesis involving thermal expansion and contraction.

  7. Stochastic dynamic model of SARS spreading

    Institute of Scientific and Technical Information of China (English)

    SHI Yaolin

    2003-01-01

    Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte Carlo test. The preliminary results indicate that the time-dependent infection rate is the most important control factor for SARS spreading. The model can be applied to prediction of the course with fluctuations of the epidemics, if the previous history of the epidemics and the future infection rate under control measures are known.

  8. Detection of spreading depolarization with intraparenchymal electrodes in the injured human brain

    DEFF Research Database (Denmark)

    Jeffcote, Toby; Hinzman, Jason M; Jewell, Sharon L

    2014-01-01

    BACKGROUND: Spreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can ...... for craniotomy. The method provides a new investigative tool for the evaluation of the contribution of these events to secondary brain injury in human patients.......BACKGROUND: Spreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can...... for traumatic brain injury or aneurysmal subarachnoid hemorrhage were monitored for depolarization events in an intensive care setting with concurrent strip (subdural) and depth (intra-parenchymal) electrode recordings. RESULTS: (1) Depolarization events can be reliably detected from intra-cortically placed...

  9. Spreading depolarizations have prolonged direct current shifts and are associated with poor outcome in brain trauma

    DEFF Research Database (Denmark)

    Hartings, Jed A; Watanabe, Tomas; Bullock, M Ross

    2011-01-01

    Cortical spreading depolarizations occur spontaneously after ischaemic, haemorrhagic and traumatic brain injury. Their effects vary spatially and temporally as graded phenomena, from infarction to complete recovery, and are reflected in the duration of depolarization measured by the negative direct...... current shift of electrocorticographic recordings. In the focal ischaemic penumbra, peri-infarct depolarizations have prolonged direct current shifts and cause progressive recruitment of the penumbra into the core infarct. In traumatic brain injury, the effects of spreading depolarizations are unknown......, although prolonged events have not been observed in animal models. To determine whether detrimental penumbral-type depolarizations occur in human brain trauma, we analysed electrocorticographic recordings obtained by subdural electrode-strip monitoring during intensive care. Of 53 patients studied, 10...

  10. Strong ties promote the epidemic prevalence in susceptible-infected-susceptible spreading dynamics

    CERN Document Server

    Cui, Ai-Xiang; Zhou, Tao

    2013-01-01

    Understanding spreading dynamics will benefit society as a whole in better preventing and controlling diseases, as well as facilitating the socially responsible information while depressing destructive rumors. In network-based spreading dynamics, edges with different weights may play far different roles: a friend from afar usually brings novel stories, and an intimate relationship is highly risky for a flu epidemic. In this article, we propose a weighted susceptible-infected-susceptible model on complex networks, where the weight of an edge is defined by the topological proximity of the two associated nodes. Each infected individual is allowed to select limited number of neighbors to contact, and a tunable parameter is introduced to control the preference to contact through high-weight or low-weight edges. Experimental results on six real networks show that the epidemic prevalence can be largely promoted when strong ties are favored in the spreading process. By comparing with two statistical null models respe...

  11. Resveratrol attenuates cisplatin renal cortical cytotoxicity by modifying oxidative stress.

    Science.gov (United States)

    Valentovic, Monica A; Ball, John G; Brown, J Mike; Terneus, Marcus V; McQuade, Elizabeth; Van Meter, Stephanie; Hedrick, Hayden M; Roy, Amy Allison; Williams, Tierra

    2014-03-01

    Cisplatin, a cancer chemotherapy drug, is nephrotoxic. The aim of this study was to investigate whether resveratrol (RES) reduced cisplatin cytotoxicity and oxidative stress. Rat renal cortical slices were pre-incubated 30min with 0 (VEH, ethanol) or 30μg/ml RES followed by 60, 90 or 120min co-incubation with 0, 75, or 150μg/ml cisplatin. Lactate dehydrogenase (LDH) leakage was unchanged at 60 and 90min by cisplatin. Cisplatin increased (pCisplatin induced oxidative stress prior to LDH leakage as cisplatin depressed glutathione peroxidase and superoxide dismutase (SOD) activity, increased lipid peroxidation, protein carbonyls and 4-hydroxynonenal (4-HNE) adducted proteins within 60min. RES failed to reverse glutathione (GSH) depression by cisplatin. In order to eliminated an extracellular interaction between RES and cisplatin, additional studies (RINSE studies) allowed a 30min RES uptake into slices, transfer of slices to buffer lacking RES, followed by 120min cisplatin incubation. RES in the RINSE studies prevented LDH leakage by cisplatin indicating that RES protection was not via a physical interaction with cisplatin in the media. These findings indicate that RES diminished cisplatin in vitro renal toxicity and prevented the development of oxidative stress.

  12. Alteration of cortical excitability in patients with fibromyalgia.

    Science.gov (United States)

    Mhalla, Alaa; de Andrade, Daniel Ciampi; Baudic, Sophie; Perrot, Serge; Bouhassira, Didier

    2010-06-01

    We assessed cortical excitability and intracortical modulation systematically, by transcranial magnetic stimulation (TMS) of the motor cortex, in patients with fibromyalgia. In total 46 female patients with fibromyalgia and 21 normal female subjects, matched for age, were included in this study. TMS was applied to the hand motor area of both hemispheres and motor evoked potentials (MEPs) were recorded for the first interosseous muscle of the contralateral hand. Single-pulse stimulation was used for measurements of the rest motor threshold (RMT) and suprathreshold MEP. Paired-pulse stimulation was used to assess short intracortical inhibition (SICI) and intracortical facilitation (ICF). Putative correlations were sought between changes in electrophysiological parameters and major clinical features of fibromyalgia, such as pain, fatigue, anxiety, depression and catastrophizing. The RMT on both sides was significantly increased in patients with fibromyalgia and suprathreshold MEP was significantly decreased bilaterally. However, these alterations, suggesting a global decrease in corticospinal excitability, were not correlated with clinical features. Patients with fibromyalgia also had lower ICF and SICI on both sides, than controls, these lower values being correlated with fatigue, catastrophizing and depression. These neurophysiological alterations were not linked to medication, as similar changes were observed in patients with or without psychotropic treatment. In conclusion, fibromyalgia is associated with deficits in intracortical modulation involving both GABAergic and glutamatergic mechanisms, possibly related to certain aspects of the pathophysiology of this chronic pain syndrome. Our data add to the growing body of evidence for objective and quantifiable changes in brain function in fibromyalgia.

  13. [Causes of depression].

    Science.gov (United States)

    Fernández, Francisco Alonso

    2011-01-01

    This paper describes four nosological categories of depressive disorder according to the fundamental or prime cause: endogen depression, situative depression, psychogen depression and somatogen (also pharmacogen or addictive) depression. Recent advances in neurobiology provide the commun pathogenic mechanism distribuited in neurochemical, neuroendocrine and neuroinmune factors, with at the end a cellular and molecular sequence beyond the synapse. There is an increased risk of depression multiplied by three or four in the elderly, obese, unemployed and inmigrant and it is very frequent in terminally ill patients with a pervasive desire for death. Finally, eight personalized preventive guidelines enable to decrease the individual risk of depression in more than a fifty per cent.

  14. Therapieresistente Depression

    Directory of Open Access Journals (Sweden)

    Holsboer-Trachsler E

    2006-01-01

    Full Text Available In der Behandlung einer Depression wird ein Nichtansprechen auf zwei adäquate Antidepressivatherapien während je 6–8 Wochen als Therapieresistenz bezeichnet. Da häufig zu geringe Dosierungen oder eine zu kurze Behandlungsdauer die Ursache für ein Nichtansprechen sind, sollte in einem ersten Schritt die medikamentöse Therapie hinsichtlich Dauer und Dosierung, eventuell unter Einbezug von Plasmaspiegelbestimmungen, überprüft und optimiert werden. Als pharmakologische Maßnahmen werden zunächst ein Wechsel des Antidepressivums und danach eine Kombination von verschiedenen Antidepressiva mit unterschiedlichem biochemischem Wirkungsansatz empfohlen. Zeigen beide nicht den gewünschten Erfolg, so sollte zusätzlich zur bestehenden Antidepressivabehandlung eine Augmentationstherapie, primär mit Lithium und/oder dem Schilddrüsenhormon T3, durchgeführt werden. Ein neuer, vielversprechender Behandlungsansatz ist eine Augmentationstherapie mit atypischen Neuroleptika. Als akut wirkende nichtpharmakologische Zusatzmaßnahme hat sich der partielle Schlafentzug bewährt. Weitere nichtpharmakologische Strategien umfassen Psychotherapie, Elektrokrampftherapie und Vagusnervstimulationsbehandlung.

  15. Increased frontal sleep slow wave activity in adolescents with major depression

    Directory of Open Access Journals (Sweden)

    Noemi Tesler

    2016-01-01

    Full Text Available Sleep slow wave activity (SWA, the major electrophysiological characteristic of deep sleep, mirrors both cortical restructuring and functioning. The incidence of Major Depressive Disorder (MDD substantially rises during the vulnerable developmental phase of adolescence, where essential cortical restructuring is taking place. The goal of this study was to assess characteristics of SWA topography in adolescents with MDD, in order to assess abnormalities in both cortical restructuring and functioning on a local level. All night high-density EEG was recorded in 15 patients meeting DSM-5 criteria for MDD and 15 sex- and age-matched healthy controls. The actual symptom severity was assessed using the Children's Depression Rating Scale—Revised (CDRS-R. Topographical power maps were calculated based on the average SWA of the first non-rapid eye movement (NREM sleep episode. Depressed adolescents exhibited significantly more SWA in a cluster of frontal electrodes compared to controls. SWA over frontal brain regions correlated positively with the CDRS-R subscore “morbid thoughts”. Self-reported sleep latency was significantly higher in depressed adolescents compared to controls whereas sleep architecture did not differ between the groups. Higher frontal SWA in depressed adolescents may represent a promising biomarker tracing cortical regions of intense use and/or restructuring.

  16. Functional neuroanatomical correlates of eye movements during rapid eye movement sleep in depressed patients.

    Science.gov (United States)

    Germain, Anne; Buysse, Daniel J; Wood, Annette; Nofzinger, Eric

    2004-04-30

    In depressed patients, REM density, or the number of rapid eye movements (REMs) per minute of REM sleep, is a correlate of depression severity and clinical outcomes. We investigated the functional neuroanatomical correlates of average REM counts (RC), an automated analog of REM density, in depression. Thirteen medication-free depressed patients underwent all night polysomnography and positron emission tomography (PET) scans using [(18)F]fluoro-2-deoxy-d-glucose ([(18)F] FDG) during REM sleep. Regression analyses were conducted with Statistical Parametric Mapping (SPM-99). Average RC significantly and positively correlated with relative regional cerebral metabolic rate of glucose (rCMRglc) bilaterally in the striate cortex, the posterior parietal cortices, and in the medial and ventrolateral prefrontal cortices. Average RC were negatively correlated with rCMRglc in areas corresponding bilaterally to the lateral occipital cortex, cuneus, temporal cortices, and parahippocampal gyri. The areas where average RC was positively correlated with rCMRglc appear to constitute a diffuse cortical system involved in the regulation of emotion-induced arousal. The observed pattern of correlations suggests that average RC may be a marker of hypofrontality during REM sleep in depressed patients.

  17. Zika Probably Not Spread Through Saliva: Study

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_167531.html Zika Probably Not Spread Through Saliva: Study Research with ... HealthDay News) -- Scientists have some interesting news about Zika: You're unlikely to get the virus from ...

  18. Spreading paths in partially observed social networks

    CERN Document Server

    Onnela, Jukka-Pekka

    2011-01-01

    Understanding how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading path lengths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using a static, structurally realistic social network as a platform for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Alt...

  19. Reactive spreading: Adsorption, ridging and compound formation

    Energy Technology Data Exchange (ETDEWEB)

    Saiz, E.; Cannon, R.M.; Tomsia, A.P.

    2000-09-11

    Reactive spreading, in which a chemically active element is added to promote wetting of noble metals on nonmetallic materials, is evaluated. Theories for the energetics and kinetics of the necessary steps involved in spreading are outlined and compared to the steps in compound formation that typically accompany reactive wetting. These include: fluid flow, active metal adsorption, including nonequilibrium effects, and triple line ridging. All of these can be faster than compound nucleation under certain conditions. Analysis and assessment of recently reported experiments on metal/ceramic systems lead to a focus on those conditions under which spreading proceeds ahead of the actual formation of a new phase at the interface. This scenario may be more typical than believed, and perhaps the most effective situation leading to enhanced spreading. A rationale for the pervasive variability and hysteresis observed during high temperature wetting also emerges.

  20. Emergence of Blind Areas in Information Spreading

    CERN Document Server

    Zhang, Zi-Ke; Han, Xiao-Pu; Liu, Chuang

    2013-01-01

    Recently, contagion-based (disease, information, etc.) spreading on social networks has been extensively studied. In this paper, other than traditional full interaction, we propose a partial interaction based spreading model, considering that the informed individuals would transmit information to only a certain fraction of their neighbors due to the transmission ability in real-world social networks. Simulation results on three representative networks (BA, ER, WS) indicate that the spreading efficiency is highly correlated with the network heterogeneity. In addition, a special phenomenon, namely \\emph{Information Blind Areas} where the network is separated by several information-unreachable clusters, will emerge from the spreading process. Furthermore, we also find that the size distribution of such information blind areas obeys power-law-like distribution, which has very similar exponent with that of site percolation. Detailed analyses show that the critical value is decreasing along with the network heterog...

  1. Superresolution improves MRI cortical segmentation with FACE

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Manjón, José V.; Coupé, Pierrick

    Brain cortical surface extraction from MRI has applications for measurement of gray matter (GM) atrophy, functional mapping, source localization and preoperative neurosurgical planning. Accurate cortex segmentation requires high resolution morphological images and several methods for extracting...

  2. Perceptual incongruence influences bistability and cortical activation

    NARCIS (Netherlands)

    Brouwer, G.J.; Tong, F.; Hagoort, P.; van Ee, R.

    2009-01-01

    We employed a parametric psychophysical design in combination with functional imaging to examine the influence of metric changes in perceptual incongruence on perceptual alternation rates and cortical responses. Subjects viewed a bistable stimulus defined by incongruent depth cues; bistability

  3. Transient cortical blindness after coronary angiography.

    Science.gov (United States)

    Alp, B N; Bozbuğa, N; Tuncer, M A; Yakut, C

    2009-01-01

    Transient cortical blindness is rarely encountered after angiography of native coronary arteries or bypass grafts. This paper reports a case of transient cortical blindness that occurred 72 h after coronary angiography in a 56-year old patient. This was the patient's fourth exposure to contrast medium. Neurological examination demonstrated cortical blindness and the absence of any focal neurological deficit. A non-contrast-enhanced computed tomographic scan of the brain revealed bilateral contrast enhancement in the occipital lobes and no evidence of cerebral haemorrhage, and magnetic resonance imaging of the brain showed no pathology. Sight returned spontaneously within 4 days and his vision gradually improved. A search of the current literature for reported cases of transient cortical blindness suggested that this is a rarely encountered complication of coronary angiography.

  4. Reversible cortical blindness after lung transplantation.

    Science.gov (United States)

    Knower, Mark T; Pethke, Scott D; Valentine, Vincent G

    2003-06-01

    Cyclosporine (CYA) is a calcineurin inhibitor widely used in immunosuppressive regimens after organ transplantation. Several neurologic side effects are frequently associated with CYA use; however, reversible cortical blindness is a rare manifestation of CYA toxicity traditionally seen after liver and bone marrow transplantation. This report presents a case of reversible cortical blindness after lung transplantation, then details the risk factors and clinical course of 28 previously well-documented cases of CYA-induced cortical blindness after transplantation. Identification of known risk factors, clinical clues, and typical radiographic findings may aid in the diagnosis of CYA-induced cortical blindness, since reduction in CYA dose or cessation of CYA therapy usually permits resolution of the neurologic effects.

  5. Cortical areas involved in Arabic number reading.

    Science.gov (United States)

    Roux, F-E; Lubrano, V; Lauwers-Cances, V; Giussani, C; Démonet, J-F

    2008-01-15

    Distinct functional pathways for processing words and numbers have been hypothesized from the observation of dissociated impairments of these categories in brain-damaged patients. We aimed to identify the cortical areas involved in Arabic number reading process in patients operated on for various brain lesions. Direct cortical electrostimulation was prospectively used in 60 brain mappings. We used object naming and two reading tasks: alphabetic script (sentences and number words) and Arabic number reading. Cortical areas involved in Arabic number reading were identified according to location, type of interference, and distinctness from areas associated with other language tasks. Arabic number reading was sustained by small cortical areas, often extremely well localized (area (Brodmann area 45), the anterior part of the dominant supramarginal gyrus (Brodmann area 40; p area (Brodmann area 37; p areas.

  6. The Diversity of Cortical Inhibitory Synapses

    Directory of Open Access Journals (Sweden)

    Yoshiyuki eKubota

    2016-04-01

    Full Text Available The most typical and well known inhibitory action in the cortical microcircuit is a strong inhibition on the target neuron by axo-somatic synapses. However, it has become clear that synaptic inhibition in the cortex is much more diverse and complicated. Firstly, at least ten or more inhibitory non-pyramidal cell subtypes engage in diverse inhibitory functions to produce the elaborate activity characteristic of the different cortical states. Each distinct non-pyramidal cell subtype has its own independent inhibitory function. Secondly, the inhibitory synapses innervate different neuronal domains, such as axons, spines, dendrites and soma, and their IPSP size is not uniform. Thus cortical inhibition is highly complex, with a wide variety of anatomical and physiological modes. Moreover, the functional significance of the various inhibitory synapse innervation styles and their unique structural dynamic behaviors differ from those of excitatory synapses. In this review, we summarize our current understanding of the inhibitory mechanisms of the cortical microcircuit.

  7. Spreading of charged micro-droplets

    Directory of Open Access Journals (Sweden)

    Joseph Iaia

    2013-09-01

    Full Text Available We consider the spreading of a charged microdroplet on a flat dielectric surface whose spreading is driven by surface tension and electrostatic repulsion. This leads to a third order nonlinear partial differential equation that gives the evolution of the height profile. Assuming the droplets are circular we are able to prove existence of solutions with infinite contact angle and in many cases we are able to prove nonexistence of solutions with finite contact angle.

  8. Mapping the Spread of Mounted Warfare

    Directory of Open Access Journals (Sweden)

    Peter Turchin

    2016-12-01

    Full Text Available Military technology is one of the most important factors affecting the evolution of complex societies. In particular, mounted warfare, the use of horse-riders in military operations, revolutionized war as it spread to different parts of Eurasia and Africa during the Ancient and Medieval eras, and to the Americas during the Early Modern period. Here we use a variety of sources to map this spread.

  9. Cortical Source Localization of Infant Cognition

    OpenAIRE

    Reynolds, GD; Richards, JE

    2009-01-01

    Neuroimaging techniques such as positron emission topography (PET) and functional magnetic resonance imaging (fMRI) have been utilized with older children and adults to identify cortical sources of perceptual and cognitive processes. However, due to practical and ethical concerns, these techniques cannot be routinely applied to infant participants. An alternative to such neuroimaging techniques appropriate for use with infant participants is high-density EEG recording and cortical source loca...

  10. CLADA: cortical longitudinal atrophy detection algorithm.

    Science.gov (United States)

    Nakamura, Kunio; Fox, Robert; Fisher, Elizabeth

    2011-01-01

    Measurement of changes in brain cortical thickness is useful for the assessment of regional gray matter atrophy in neurodegenerative conditions. A new longitudinal method, called CLADA (cortical longitudinal atrophy detection algorithm), has been developed for the measurement of changes in cortical thickness in magnetic resonance images (MRI) acquired over time. CLADA creates a subject-specific cortical model which is longitudinally deformed to match images from individual time points. The algorithm was designed to work reliably for lower resolution images, such as the MRIs with 1×1×5 mm(3) voxels previously acquired for many clinical trials in multiple sclerosis (MS). CLADA was evaluated to determine reproducibility, accuracy, and sensitivity. Scan-rescan variability was 0.45% for images with 1mm(3) isotropic voxels and 0.77% for images with 1×1×5 mm(3) voxels. The mean absolute accuracy error was 0.43 mm, as determined by comparison of CLADA measurements to cortical thickness measured directly in post-mortem tissue. CLADA's sensitivity for correctly detecting at least 0.1mm change was 86% in a simulation study. A comparison to FreeSurfer showed good agreement (Pearson correlation=0.73 for global mean thickness). CLADA was also applied to MRIs acquired over 18 months in secondary progressive MS patients who were imaged at two different resolutions. Cortical thinning was detected in this group in both the lower and higher resolution images. CLADA detected a higher rate of cortical thinning in MS patients compared to healthy controls over 2 years. These results show that CLADA can be used for reliable measurement of cortical atrophy in longitudinal studies, even in lower resolution images.

  11. Cortical Neural Computation by Discrete Results Hypothesis

    Science.gov (United States)

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  12. Mean field methods for cortical network dynamics

    DEFF Research Database (Denmark)

    Hertz, J.; Lerchner, Alexander; Ahmadi, M.

    2004-01-01

    We review the use of mean field theory for describing the dynamics of dense, randomly connected cortical circuits. For a simple network of excitatory and inhibitory leaky integrate- and-fire neurons, we can show how the firing irregularity, as measured by the Fano factor, increases with the stren...... cortex. Finally, an extension of the model to describe an orientation hypercolumn provides understanding of how cortical interactions sharpen orientation tuning, in a way that is consistent with observed firing statistics...

  13. Cortical depth dependence of the diffusion anisotropy in the human cortical gray matter in vivo.

    Directory of Open Access Journals (Sweden)

    Trong-Kha Truong

    Full Text Available Diffusion tensor imaging (DTI is typically used to study white matter fiber pathways, but may also be valuable to assess the microstructure of cortical gray matter. Although cortical diffusion anisotropy has previously been observed in vivo, its cortical depth dependence has mostly been examined in high-resolution ex vivo studies. This study thus aims to investigate the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo on a clinical 3 T scanner. Specifically, a novel multishot constant-density spiral DTI technique with inherent correction of motion-induced phase errors was used to achieve a high spatial resolution (0.625 × 0.625 × 3 mm and high spatial fidelity with no scan time penalty. The results show: (i a diffusion anisotropy in the cortical gray matter, with a primarily radial diffusion orientation, as observed in previous ex vivo and in vivo studies, and (ii a cortical depth dependence of the fractional anisotropy, with consistently higher values in the middle cortical lamina than in the deep and superficial cortical laminae, as observed in previous ex vivo studies. These results, which are consistent across subjects, demonstrate the feasibility of this technique for investigating the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo.

  14. Cortical depth dependence of the diffusion anisotropy in the human cortical gray matter in vivo.

    Science.gov (United States)

    Truong, Trong-Kha; Guidon, Arnaud; Song, Allen W

    2014-01-01

    Diffusion tensor imaging (DTI) is typically used to study white matter fiber pathways, but may also be valuable to assess the microstructure of cortical gray matter. Although cortical diffusion anisotropy has previously been observed in vivo, its cortical depth dependence has mostly been examined in high-resolution ex vivo studies. This study thus aims to investigate the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo on a clinical 3 T scanner. Specifically, a novel multishot constant-density spiral DTI technique with inherent correction of motion-induced phase errors was used to achieve a high spatial resolution (0.625 × 0.625 × 3 mm) and high spatial fidelity with no scan time penalty. The results show: (i) a diffusion anisotropy in the cortical gray matter, with a primarily radial diffusion orientation, as observed in previous ex vivo and in vivo studies, and (ii) a cortical depth dependence of the fractional anisotropy, with consistently higher values in the middle cortical lamina than in the deep and superficial cortical laminae, as observed in previous ex vivo studies. These results, which are consistent across subjects, demonstrate the feasibility of this technique for investigating the cortical depth dependence of the diffusion anisotropy in the human cortex in vivo.

  15. The cortical and sub-cortical network of sensory evoked response in healthy subjects.

    Science.gov (United States)

    Muthuraman, M; Hellriegel, H; Groppa, S; Deuschl, G; Raethjen, J

    2013-01-01

    The aim of this study was to find the cortical and sub-cortical network responsible for the sensory evoked coherence in healthy subjects during electrical stimulation of right median nerve at wrist. The multitaper method was used to estimate the power and coherence spectrum followed by the source analysis method dynamic imaging of coherent sources (DICS) to find the highest coherent source for the basic frequency 3 Hz and the complete cortical and sub-cortical network responsible for the sensory evoked coherence in healthy subjects. The highest coherent source for the basic frequency was in the posterior parietal cortex for all the subjects. The cortical and sub-cortical network comprised of the primary sensory motor cortex (SI), secondary sensory motor cortex (SII), frontal cortex and medial pulvinar nucleus in the thalamus. The cortical and sub-cortical network responsible for the sensory evoked coherence was found successfully with a 64-channel EEG system. The sensory evoked coherence is involved with a thalamo-cortical network in healthy subjects.

  16. Diurnal trend in EEG interhemispheric asymmetry in endogenous depressions

    Directory of Open Access Journals (Sweden)

    T S Melnikova

    2011-01-01

    Full Text Available A trend in EEG interhemispheric asymmetry was studied in patients with endogenous depressions in morning and evening hours. In the morning, the spectral power of alpha rhythm particularly in the occipital cortical regions, proved to be higher than that in the evening. In the morning, the interhemispheric differences in the power of occipital alpha rhythm were leveled off while in the evening there was normalization of interhemispheric balance with the higher power of alpha rhythm in the right occipital region. Analysis of the mean coherence (mean Coh of alpha rhythm in individual cortical regions revealed that the patients with endogenous depression had higher readings mainly in the parietal and central regions of both hemispheres and in the right temporal regions in the morning than in the evening. The occipital and posttemporal regions showed an inverse trend in the mean Coh - it was lower in the morning than in the evening

  17. Gossip spread in social network Models

    Science.gov (United States)

    Johansson, Tobias

    2017-04-01

    Gossip almost inevitably arises in real social networks. In this article we investigate the relationship between the number of friends of a person and limits on how far gossip about that person can spread in the network. How far gossip travels in a network depends on two sets of factors: (a) factors determining gossip transmission from one person to the next and (b) factors determining network topology. For a simple model where gossip is spread among people who know the victim it is known that a standard scale-free network model produces a non-monotonic relationship between number of friends and expected relative spread of gossip, a pattern that is also observed in real networks (Lind et al., 2007). Here, we study gossip spread in two social network models (Toivonen et al., 2006; Vázquez, 2003) by exploring the parameter space of both models and fitting them to a real Facebook data set. Both models can produce the non-monotonic relationship of real networks more accurately than a standard scale-free model while also exhibiting more realistic variability in gossip spread. Of the two models, the one given in Vázquez (2003) best captures both the expected values and variability of gossip spread.

  18. Wave directional spreading from point field measurements

    Science.gov (United States)

    McAllister, M. L.; Venugopal, V.; Borthwick, A. G. L.

    2017-04-01

    Ocean waves have multidirectional components. Most wave measurements are taken at a single point, and so fail to capture information about the relative directions of the wave components directly. Conventional means of directional estimation require a minimum of three concurrent time series of measurements at different spatial locations in order to derive information on local directional wave spreading. Here, the relationship between wave nonlinearity and directionality is utilized to estimate local spreading without the need for multiple concurrent measurements, following Adcock & Taylor (Adcock & Taylor 2009 Proc. R. Soc. A 465, 3361-3381. (doi:10.1098/rspa.2009.0031)), with the assumption that directional spreading is frequency independent. The method is applied to measurements recorded at the North Alwyn platform in the northern North Sea, and the results compared against estimates of wave spreading by conventional measurement methods and hindcast data. Records containing freak waves were excluded. It is found that the method provides accurate estimates of wave spreading over a range of conditions experienced at North Alwyn, despite the noisy chaotic signals that characterize such ocean wave data. The results provide further confirmation that Adcock and Taylor's method is applicable to metocean data and has considerable future promise as a technique to recover estimates of wave spreading from single point wave measurement devices.

  19. Modeling the mechanics of cells in the cell-spreading process driven by traction forces

    Science.gov (United States)

    Fang, Yuqiang; Lai, King W. C.

    2016-04-01

    Mechanical properties of cells and their mechanical interaction with the extracellular environments are main factors influencing cellular function, thus indicating the progression of cells in different disease states. By considering the mechanical interactions between cell adhesion molecules and the extracellular environment, we developed a cell mechanical model that can characterize the mechanical changes in cells during cell spreading. A cell model was established that consisted of various main subcellular components, including cortical cytoskeleton, nuclear envelope, actin filaments, intermediate filaments, and microtubules. We demonstrated the structural changes in subcellular components and the changes in spreading areas during cell spreading driven by traction forces. The simulation of nanoindentation tests was conducted by integrating the indenting force to the cell model. The force-indentation curve of the cells at different spreading states was simulated, and the results showed that cell stiffness increased with increasing traction forces, which were consistent with the experimental results. The proposed cell mechanical model provides a strategy to investigate the mechanical interactions of cells with the extracellular environments through the adhesion molecules and to reveal the cell mechanical properties at the subcellular level as cells shift from the suspended state to the adherent state.

  20. Cortical thinning in former professional soccer players.

    Science.gov (United States)

    Koerte, Inga K; Mayinger, Michael; Muehlmann, Marc; Kaufmann, David; Lin, Alexander P; Steffinger, Denise; Fisch, Barbara; Rauchmann, Boris-Stephan; Immler, Stefanie; Karch, Susanne; Heinen, Florian R; Ertl-Wagner, Birgit; Reiser, Maximilian; Stern, Robert A; Zafonte, Ross; Shenton, Martha E

    2016-09-01

    Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process.

  1. Cortical swallowing processing in early subacute stroke

    Directory of Open Access Journals (Sweden)

    Fischer Maren

    2011-03-01

    Full Text Available Abstract Background Dysphagia is a major complication in hemispheric as well as brainstem stroke patients causing aspiration pneumonia and increased mortality. Little is known about the recovery from dysphagia after stroke. The aim of the present study was to determine the different patterns of cortical swallowing processing in patients with hemispheric and brainstem stroke with and without dysphagia in the early subacute phase. Methods We measured brain activity by mean of whole-head MEG in 37 patients with different stroke localisation 8.2 +/- 4.8 days after stroke to study changes in cortical activation during self-paced swallowing. An age matched group of healthy subjects served as controls. Data were analyzed by means of synthetic aperture magnetometry and group analyses were performed using a permutation test. Results Our results demonstrate strong bilateral reduction of cortical swallowing activation in dysphagic patients with hemispheric stroke. In hemispheric stroke without dysphagia, bilateral activation was found. In the small group of patients with brainstem stroke we observed a reduction of cortical activation and a right hemispheric lateralization. Conclusion Bulbar central pattern generators coordinate the pharyngeal swallowing phase. The observed right hemispheric lateralization in brainstem stroke can therefore be interpreted as acute cortical compensation of subcortically caused dysphagia. The reduction of activation in brainstem stroke patients and dysphagic patients with cortical stroke could be explained in terms of diaschisis.

  2. The development of cortical columns: role of Fragile X mental retardation protein.

    Science.gov (United States)

    Bureau, Ingrid

    2009-05-01

    Neuronal circuits in the brain are complex and precise. Here, I review aspects of the development of cortical columns in the rodent barrel cortex, focusing on the anatomical and functional data describing the maturation of ascending glutamatergic circuits. Projections from layer 4 to layer 3 develop into cortical columns with little macroscopic refinement. Depriving animals of normal sensory experience induces long-term synaptic depression but does not perturb this pattern of development. Mouse models of mental retardation can help us understand the mechanisms of development of cortical columns. Fmr1 knock-out (ko) mice, a model for Fragile X syndrome, lack Fragile X mental retardation protein (FMRP), a suppressor of translation present in synapses. Because FMRP expression is stimulated by neuronal activity, Fmr1-ko mice provide a model to survey the role of sensory input in brain development. Layer 4 to layer 3 projections are altered in multiple ways in the young mutant mice: connection rate is low and layer 4 cell axons are spatially diffuse. Sensory deprivation rescues the connection rate phenotype. The interaction of FMRP and neuronal activity in the development of cortical circuits is discussed.

  3. EFFECT OF INTERFERON-α ON CORTICAL GLUTAMATE IN PATIENTS WITH HEPATITIS C: A PROTON MRS STUDY

    Science.gov (United States)

    Taylor, Matthew J; Godlewska, Beata; Near, Jamie; Christmas, David; Potokar, John; Collier, Jane; Klenerman, Paul; Barnes, Eleanor; Cowen, Philip J

    2013-01-01

    Background The development of depressive symptomatology is a recognised complication of treatment with the cytokine, interferon-α, and has been seen as supporting inflammatory theories of the pathophysiology of major depression. Major depression has been associated with changes in glutamatergic activity and recent formulations of interferon-induced depression have implicated neurotoxic influences which could also lead to changes in glutamate function. The present study used magnetic resonance spectroscopy (MRS) to measure both glutamate and its major metabolite, glutamine in patients with hepatitis C who received treatment with pegylated-interferon-α and ribavirin. Methods MRS measurements of glutamate and glutamine were taken from a 25×20×20mm voxel including pregenual anterior cingulate cortex in 12 patients before and after 4-6 weeks treatment with interferon. Results Interferon treatment led to an increase in cortical levels of glutamine (p= 0.02) and a significant elevation in the ratio of glutamine to glutamate (p<.01). Further, changes in glutamine level correlated significantly with ratings of depression and anxiety at the time of the second scan. Conclusions We conclude that treatment with interferon-α is associated with MRS-visible changes in glutamatergic metabolism. However, the changes seen differ from those reported in major depression which suggests that the pathophysiology of interferon-induced depression may be distinct from that of major depression more generally. PMID:23659574

  4. Spreading of liquid drops over porous substrates.

    Science.gov (United States)

    Starov, V M; Zhdanov, S A; Kosvintsev, S R; Sobolev, V D; Velarde, M G

    2003-07-01

    The spreading of small liquid drops over thin and thick porous layers (dry or saturated with the same liquid) has been investigated in the case of both complete wetting (silicone oils of different viscosities) and partial wetting (aqueous SDS solutions of different concentrations). Nitrocellulose membranes of different porosity and different average pore size have been used as a model of thin porous layers, glass and metal filters have been used as a model of thick porous substrates. The first problem under investigation has been the spreading of small liquid drops over thin porous layers saturated with the same liquid. An evolution equation describing the drop spreading has been deduced, which showed that both an effective lubrication and the liquid exchange between the drop and the porous substrates are equally important. Spreading of silicone oils over different nitrocellulose microfiltration membranes was carried out. The experimental laws of the radius of spreading on time confirmed the theory predictions. The spreading of small liquid drops over thin dry porous layers has also been investigated from both theoretical and experimental points of view. The drop motion over a dry porous layer appears caused by the interplay of two processes: (a). the spreading of the drop over already saturated parts of the porous layer, which results in a growth of the drop base, and (b). the imbibition of the liquid from the drop into the porous substrate, which results in a shrinkage of the drop base and a growth of the wetted region inside the porous layer. As a result of these two competing processes the radius of the drop base goes through a maximum as time proceeds. A system of two differential equations has been derived to describe the time evolution of the radii of both the drop base and the wetted region inside the porous layer. This system includes two parameters, one accounts for the effective lubrication coefficient of the liquid over the wetted porous substrate, and

  5. Parallel Impurity Spreading During Massive Gas Injection

    Science.gov (United States)

    Izzo, V. A.

    2016-10-01

    Extended-MHD simulations of disruption mitigation in DIII-D demonstrate that both pre-existing islands (locked-modes) and plasma rotation can significantly influence toroidal spreading of impurities following massive gas injection (MGI). Given the importance of successful disruption mitigation in ITER and the large disparity in device parameters, empirical demonstrations of disruption mitigation strategies in present tokamaks are insufficient to inspire unreserved confidence for ITER. Here, MHD simulations elucidate how impurities injected as a localized jet spread toroidally and poloidally. Simulations with large pre-existing islands at the q = 2 surface reveal that the magnetic topology strongly influences the rate of impurity spreading parallel to the field lines. Parallel spreading is largely driven by rapid parallel heat conduction, and is much faster at low order rational surfaces, where a short parallel connection length leads to faster thermal equilibration. Consequently, the presence of large islands, which alter the connection length, can slow impurity transport; but the simulations also show that the appearance of a 4/2 harmonic of the 2/1 mode, which breaks up the large islands, can increase the rate of spreading. This effect is seen both for simulations with spontaneously growing and directly imposed 4/2 modes. Given the prevalence of locked-modes as a cause of disruptions, understanding the effect of large islands is of particular importance. Simulations with and without islands also show that rotation can alter impurity spreading, even reversing the predominant direction of spreading, which is toward the high-field-side in the absence of rotation. Given expected differences in rotation for ITER vs. DIII-D, rotation effects are another important consideration when extrapolating experimental results. Work supported by US DOE under DE-FG02-95ER54309.

  6. A network model for Ebola spreading.

    Science.gov (United States)

    Rizzo, Alessandro; Pedalino, Biagio; Porfiri, Maurizio

    2016-04-01

    The availability of accurate models for the spreading of infectious diseases has opened a new era in management and containment of epidemics. Models are extensively used to plan for and execute vaccination campaigns, to evaluate the risk of international spreadings and the feasibility of travel bans, and to inform prophylaxis campaigns. Even when no specific therapeutical protocol is available, as for the Ebola Virus Disease (EVD), models of epidemic spreading can provide useful insight to steer interventions in the field and to forecast the trend of the epidemic. Here, we propose a novel mathematical model to describe EVD spreading based on activity driven networks (ADNs). Our approach overcomes the simplifying assumption of homogeneous mixing, which is central to most of the mathematically tractable models of EVD spreading. In our ADN-based model, each individual is not bound to contact every other, and its network of contacts varies in time as a function of an activity potential. Our model contemplates the possibility of non-ideal and time-varying intervention policies, which are critical to accurately describe EVD spreading in afflicted countries. The model is calibrated from field data of the 2014 April-to-December spreading in Liberia. We use the model as a predictive tool, to emulate the dynamics of EVD in Liberia and offer a one-year projection, until December 2015. Our predictions agree with the current vision expressed by professionals in the field, who consider EVD in Liberia at its final stage. The model is also used to perform a what-if analysis to assess the efficacy of timely intervention policies. In particular, we show that an earlier application of the same intervention policy would have greatly reduced the number of EVD cases, the duration of the outbreak, and the infrastructures needed for the implementation of the intervention.

  7. High-temperature spreading kinetics of metals

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, N.

    2005-05-15

    In this PhD work a drop transfer setup combined with high speed photography has been used to analyze the spreading of Ag on polished polycrystalline Mo and single crystalline Mo (110) and (100) substrates. The objective of this work was to unveil the basic phenomena controlling spreading in metal-metal systems. The observed spreading kinetics were compared with current theories of low and high temperature spreading such as a molecular kinetic model and a fluid flow model. Analyses of the data reveal that the molecular model does describe the fastest velocity data well for all the investigated systems. Therefore, the energy which is dissipated during the spreading process is a dissipation at the triple line rather than dissipation due to the viscosity in the liquid. A comparison of the determined free activation energy for wetting of {delta}G95{approx}145kJ/mol with literature values allows the statement that the rate determining step seems to be a surface diffusion of the Ag atoms along the triple line. In order to investigate possible ridge formation, due to local atomic diffusion of atoms of the substrate at the triple during the spreading process, grooving experiments of the polycrystalline Mo were performed to calculate the surface diffusities that will control ridge evolution. The analyses of this work showed that a ridge formation at the fastest reported wetting velocities was not possible if there is no initial perturbation for a ridge. If there was an initial perturbation for a ridge the ridge had to be much smaller than 1 nm in order to be able to move with the liquid font. Therefore ridge formation does not influence the spreading kinetics for the studied system and the chosen conditions. SEM, AFM and TEM investigations of the triple line showed that ridge formation does also not occur at the end of the wetting experiment when the drop is close to equilibrium and the wetting velocity is slow. (orig.)

  8. [Depression in schizophrenia].

    Science.gov (United States)

    Rigaud, A S

    1991-03-01

    Depressive symptoms are frequent during schizophrenia. Depression occurs in the course of a schizo affective psychose or in the course of a schizophrenia (either with acute psychotic symptoms, either without acute psychotic symptoms). Differentiating depression from negative symptoms of schizophrenia or from antipsychotic drug induced side effects can be difficult. The question to know whether depression is intrinsic to the disease process itself whether it is secondary to the schizophrenic process is still a matter of inquiry. Efficacy of antidepressive drugs during depression in schizophrenia remains a matter of controversy. Depression increases the risk for pejorative evolution and for suicide in schizophrenia.

  9. Variation of wave directional spread parameters along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.

    Directional spreading of wave energy is popularly modeled with the help of the Cosine Power model and it mainly depends on the spreading parameter. This paper describes the variation of the spreading parameter estimated based on the wave data...

  10. Overlapping spreading centres: new accretion geometry on the East Pacific Rise

    Science.gov (United States)

    MacDonald, Ken C.

    1983-03-01

    In a detailed Seabeam investigation of the East Pacific Rise (EPR) from 8°N to 18°N, a new kind of volcano-tectonic geometry associated with fast-spreading centres has been discovered (Figs 1, 2). At several locations along the rise axis the neovolcanic zone is discontinuous, and is laterally offset a short distance (1-15 km). In contrast to a classic ridge-transform-ridge plate boundary, however, the offset ridge terminations overlap each other by a distance approximately equal to or greater than the offset. They curve sharply towards each other and often merge into one another along strike. Separating the overlapping spreading centres (OSCs) is a closed contour depression up to several hundred metres deep which is sub-parallel to the trend of the OSCs. The region between the OSCs is a complex zone of both shear and rotational deformation with no obvious transform parallel structures. Based on wax model studies of spreading centres, we suggest here that transform faults fail to develop at fast spreading centres where the lateral offsets are small (floor created at fast spreading rates may bear the imprint of this newly observed process.

  11. Spreading of Cholera through Surface Water

    Science.gov (United States)

    Bertuzzo, E.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2009-12-01

    Cholera epidemics are still a major public health concern to date in many areas of the world. In order to understand and forecast cholera outbreaks, one of the most important factors is the role played by the environmental matrix in which the disease spreads. We study how river networks, acting as environmental corridors for pathogens, affect the spreading of cholera epidemics. The environmental matrix in which the disease spreads is constituted by different human communities and their hydrologic interconnections. Each community is characterized by its spatial position, population size, water resources availability and hygiene conditions. By implementing a spatially explicit cholera model we seek the effects on epidemic dynamics of: i) the topology and metrics of the pathogens pathways that connect different communities; ii) the spatial distribution of the population size; and iii) the spatial distributions and quality of surface water resources and public health conditions, and how they vary with population size. The model has been applied to study the space-time evolution of a well documented cholera epidemic occurred in the KwaZulu-Natal province of South Africa. The epidemic lasted for two years and involved about 140,000 confirmed cholera cases. The model does well in reproducing the distribution of the cholera cases during the two outbreaks as well as their spatial spreading. We further extend the model by deriving the speed of propagation of traveling fronts in the case of uniformly distributed systems for different topologies: one and two dimensional lattices and river networks. The derivation of the spreading celerity proves instrumental in establishing the overall conditions for the relevance of spatially explicit models. The conditions are sought by comparison between spreading and disease timescales. Consider a cholera epidemic that starts from a point and spreads throughout a finite size system, it is possible to identify two different timescales: i

  12. Free energy analysis of cell spreading.

    Science.gov (United States)

    McEvoy, Eóin; Deshpande, Vikram S; McGarry, Patrick

    2017-10-01

    In this study we present a steady-state adaptation of the thermodynamically motivated stress fiber (SF) model of Vigliotti et al. (2015). We implement this steady-state formulation in a non-local finite element setting where we also consider global conservation of the total number of cytoskeletal proteins within the cell, global conservation of the number of binding integrins on the cell membrane, and adhesion limiting ligand density on the substrate surface. We present a number of simulations of cell spreading in which we consider a limited subset of the possible deformed spread-states assumed by the cell in order to examine the hypothesis that free energy minimization drives the process of cell spreading. Simulations suggest that cell spreading can be viewed as a competition between (i) decreasing cytoskeletal free energy due to strain induced assembly of cytoskeletal proteins into contractile SFs, and (ii) increasing elastic free energy due to stretching of the mechanically passive components of the cell. The computed minimum free energy spread area is shown to be lower for a cell on a compliant substrate than on a rigid substrate. Furthermore, a low substrate ligand density is found to limit cell spreading. The predicted dependence of cell spread area on substrate stiffness and ligand density is in agreement with the experiments of Engler et al. (2003). We also simulate the experiments of Théry et al. (2006), whereby initially circular cells deform and adhere to "V-shaped" and "Y-shaped" ligand patches. Analysis of a number of different spread states reveals that deformed configurations with the lowest free energy exhibit a SF distribution that corresponds to experimental observations, i.e. a high concentration of highly aligned SFs occurs along free edges, with lower SF concentrations in the interior of the cell. In summary, the results of this study suggest that cell spreading is driven by free energy minimization based on a competition between decreasing

  13. Post-Tanner spreading of nematic droplets

    Energy Technology Data Exchange (ETDEWEB)

    Mechkov, S; Oshanin, G [Laboratoire de Physique Theorique de la Matiere Condensee, Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 5 (France); Cazabat, A M, E-mail: mechkov@lptmc.jussieu.f, E-mail: anne-marie.cazabat@lps.ens.f, E-mail: oshanin@lptmc.jussieu.f [Laboratoire de Physique Statistique, Ecole Normale Superieure, 75252 Paris Cedex 5 (France)

    2009-11-18

    The quasistationary spreading of a circular liquid drop on a solid substrate typically obeys the so-called Tanner law, with the instantaneous base radius R(t) growing with time as Rapproxt{sup 1/10}-an effect of the dominant role of capillary forces for a small-sized droplet. However, for droplets of nematic liquid crystals, a faster spreading law sets in at long times, so that Rapproxt{sup a}lpha with alpha significantly larger than the Tanner exponent 1/10. In the framework of the thin film model (or lubrication approximation), we describe this 'acceleration' as a transition to a qualitatively different spreading regime driven by a strong substrate-liquid interaction specific to nematics (antagonistic anchoring at the interfaces). The numerical solution of the thin film equation agrees well with the available experimental data for nematics, even though the non-Newtonian rheology has yet to be taken into account. Thus we complement the theory of spreading with a post-Tanner stage, noting that the spreading process can be expected to cross over from the usual capillarity-dominated stage to a regime where the whole reservoir becomes a diffusive film in the sense of Derjaguin.

  14. The role of BDNF in depression on the basis of its location in the neural circuitry

    Institute of Scientific and Technical Information of China (English)

    Hui YU; Zhe-yu CHEN

    2011-01-01

    Depression is one of the most prevalent and life-threatening forms of mental illnesses and the neural circuitry underlying depression remains incompletely understood. Most attention in the field has focused on hippocampal and frontal cortical regions for their roles in depression and antidepressant action. While these regions no doubt play important roles in the mental illness, there is compelling evi-dence that other brain regions are also involved. Brain-derived neurotrophic factor (BDNF) is broadly expressed in the developing and adult mammalian brain and has been implicated in development, neural regeneration, synaptic transmission, synaptic plasticity and neurogenesis. Recently BDNF has been shown to play an important role in the pathophysiology of depression, however there are con-troversial reports about the effects of BDNF on depression. Here, we present an overview of the current knowledge concerning BDNF actions and associated intracellular signaling in hippocampus, prefrontal cortex, nucleus accumbens (NAc) and amygdala as their rela-tion to depression.

  15. Overlapping Spreading Centers: Implications from Crack Growth Simulation by the Displacement Discontinuity Method

    Science.gov (United States)

    Sempere, Jean-Christophe; MacDonald, Ken C.

    1986-02-01

    Overlapping spreading centers (OSC's) are a fundamental aspect of accretionary processes at intermediate and fast-spreading centers and typically occur at deep points along the axial depth profile. They have a characteristic geometry consisting of two en echelon overlapping, curving ridges separated by an elongated depression. The length to width ratio of this overlap basin is typically 3∶1. We have been successful in reproducing the overlapping spreading center geometry by modelling the growth of two initially parallel elastic cracks of given length and offset in a tensile stress field at infinity. A boundary element displacement discontinuity method was used to solve this problem. Our calculated results are compared with seafloor observations in terms of the size and shape of the overlap region. For small OSC's, there is a very good agreement between calculations and observations but, for large ones, the overlap basin tends to be longer than our predicted results indicate. This suggests that the assumptions made in the model (i.e., perfectly elastic, isotropic and homogeneous medium) are perhaps valid for the brittle lid above the magma chamber that underlies OSC's with small offsets (OSC's with large offsets. Our modelling shows that the initial interaction of closely spaced surface ruptures along spreading centers is to deflect away from one another as they approach. The deflection will be the greatest for small misalignments of the fracture systems, thus even minor misalignments of the spreading centers may result in the development of OSC's. Where the misalignment is less than the width of the cracking front, the fracture systems may meet head-on creating a saddle point along the axial depth profile. Our results support the hypothesis suggested by Macdonald et al. [1984] in which overlapping spreading centers develop where two magmatic pulses migrate toward each other along the strike of the spreading center following fracture systems and magmatic conduits

  16. Quantitative radiology: radiogrammetry of cortical bone.

    Science.gov (United States)

    Dequeker, J

    1976-11-01

    Based on personal experience and data in the literature, an overview is given of radiogrammetry of cortical bone of the second metacarpal. There is a within- and between-observer error which amounts respectively to 1.2 and 1.5% for the outer diameter and 4.8 and 6.4% for the inner diameter. The systematic + or-- trend between observers indicates that one observer working according to certain defined rules obtains the most reliable results. There is a large variability in amount of bone within one age and sex group which is partly due to skeletal size differences, are insufficient since skeletal size differences still exist. The variability is reduced when the data are divided into strata of skeletal size. Since cortical area shows the best correlation with outer diameter within each age group and since cortical area represents best the ash content of the bones the values of this index are most suited to be grouped according to outer diameter. In differentiating pathological from physiological bone loss this procedure is an improvement on the previously published indices of amount of bone. When comparing different populations this method has advantages since skeletal size differences are eliminated. Comparing seven populations it was found that populations living in the United States of America have more bone for a given skeletal size than populations in Europe or Nigeria. Bone loss with age is a general phenomenon but differences in rate of loss are observed between the sexes and between ethnic different populations. The decrease of bone mass is faster after the age of 50 years in woman than in men. Blacks living in the United States loose less bone with age than whites. Radiogrammetry of cortical bone in groups gives useful information on bond remodelling during ageing and in pathological conditions. At an individual level, however, it is difficult to evaluate changes on a short term basis with radiogrammetry. Radiogrammetry of cortical bone is a simple and

  17. Social distancing strategies against disease spreading

    CERN Document Server

    Valdez, L D; Macri, P A; Braunstein, L A

    2013-01-01

    The recurrent infectious diseases and their increasing impact on the society has promoted the study of strategies to slow down the epidemic spreading. In this review we outline the applications of percolation theory to describe strategies against epidemic spreading on complex networks. We give a general outlook of the relation between link percolation and the susceptible-infected-recovered model, and introduce the node void percolation process to describe the dilution of the network composed by healthy individual, $i.e$, the network that sustain the functionality of a society. Then, we survey two strategies: the quenched disorder strategy where an heterogeneous distribution of contact intensities is induced in society, and the intermittent social distancing strategy where health individuals are persuaded to avoid contact with their neighbors for intermittent periods of time. Using percolation tools, we show that both strategies may halt the epidemic spreading. Finally, we discuss the role of the transmissibil...

  18. Epidemic spreading on evolving signed networks

    CERN Document Server

    Saeedian, M; Jafari, G R; Kertesz, J

    2016-01-01

    Most studies of disease spreading consider the underlying social network as obtained without the contagion, though epidemic influences peoples willingness to contact others: A friendly contact may be turned to unfriendly to avoid infection. We study the susceptible-infected (SI) disease spreading model on signed networks, in which each edge is associated with a positive or negative sign representing the friendly or unfriendly relation between its end nodes. In a signed network, according to Heiders theory, edge signs evolve such that finally a state of structural balance is achieved, corresponding to no frustration in physics terms. However, the danger of infection affects the evolution of its edge signs. To describe the coupled problem of the sign evolution and disease spreading, we generalize the notion of structural balance by taking into account the state of the nodes. We introduce an energy function and carry out Monte-Carlo simulations on complete networks to test the energy landscape, where we find loc...

  19. Temporal network structures controlling disease spreading

    Science.gov (United States)

    Holme, Petter

    2016-08-01

    We investigate disease spreading on eight empirical data sets of human contacts (mostly proximity networks recording who is close to whom, at what time). We compare three levels of representations of these data sets: temporal networks, static networks, and a fully connected topology. We notice that the difference between the static and fully connected networks—with respect to time to extinction and average outbreak size—is smaller than between the temporal and static topologies. This suggests that, for these data sets, temporal structures influence disease spreading more than static-network structures. To explain the details in the differences between the representations, we use 32 network measures. This study concurs that long-time temporal structures, like the turnover of nodes and links, are the most important for the spreading dynamics.

  20. Substrate stress relaxation regulates cell spreading

    Science.gov (United States)

    Chaudhuri, Ovijit; Gu, Luo; Darnell, Max; Klumpers, Darinka; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Mooney, David J.

    2015-02-01

    Studies of cellular mechanotransduction have converged upon the idea that cells sense extracellular matrix (ECM) elasticity by gauging resistance to the traction forces they exert on the ECM. However, these studies typically utilize purely elastic materials as substrates, whereas physiological ECMs are viscoelastic, and exhibit stress relaxation, so that cellular traction forces exerted by cells remodel the ECM. Here we investigate the influence of ECM stress relaxation on cell behaviour through computational modelling and cellular experiments. Surprisingly, both our computational model and experiments find that spreading for cells cultured on soft substrates that exhibit stress relaxation is greater than cells spreading on elastic substrates of the same modulus, but similar to that of cells spreading on stiffer elastic substrates. These findings challenge the current view of how cells sense and respond to the ECM.

  1. Disordered contact process with asymmetric spreading.

    Science.gov (United States)

    Juhász, Róbert

    2013-02-01

    An asymmetric variant of the contact process where the activity spreads with different and independent random rates to the left and to the right is introduced. A real space renormalization scheme is formulated for the model by means of which it is shown that the local asymmetry of spreading is irrelevant on large scales if the model is globally (statistically) symmetric. Otherwise, in the presence of a global bias in either direction, the renormalization method predicts two distinct phase transitions, which are related to the spreading of activity in and against the direction of the bias. The latter is found to be described by an infinite randomness fixed point while the former is not.

  2. Extended oil spill spreading with Langmuir circulation.

    Science.gov (United States)

    Simecek-Beatty, Debra; Lehr, William J

    2017-09-15

    When spilled in the ocean, most crude oils quickly spread into a thin film that ruptures into smaller slicks distributed over a larger area. Observers have also reported the film tearing apart into streaks that eventually merge forming fewer but longer bands of floating oil. Understanding this process is important to model oil spill transport. First, slick area is calculated using a spreading model. Next, Langmuir circulation models are used to approximate the merging of oiled bands. Calculations are performed on Troll blended and Alaska North Slope crude oils and results compared with measurements from the 1990s North Sea field experiments. Langmuir circulation increases the oil area but decreases the surface coverage of oil. This work modifies existing oil spreading formulas by providing a surface area correction due to the effects of Langmuir circulation. The model's simplicity is advantageous in situations with limited data, such as emergency oil spill response. Published by Elsevier Ltd.

  3. Temporal network structures controlling disease spreading

    CERN Document Server

    Holme, Petter

    2016-01-01

    We investigate disease spreading on eight empirical data sets of human contacts (mostly proximity networks recording who is close to whom, at what time). We compare three levels of representations of these data sets: temporal networks, static networks and a fully connected topology. We notice that the difference between the static and fully-connected networks -- with respect to time to extinction and average outbreak size -- is smaller than between the temporal and static topologies. This suggests that, for these data sets, temporal structures influence disease spreading more than static network structures. To explain the details in the differences between the representations, we use 32 network measures. This study concur that long-time temporal structures, like the turnover of nodes and links, are the most important for the spreading dynamics.

  4. Memory training in depression

    NARCIS (Netherlands)

    Becker, E.S.; Vanderhasselt, M.A.; Vrijsen, J.N.

    2015-01-01

    Memory biases, that is, general memory impairments as well as specific mood-congruent memory biases, are important vulnerability factors in depression. Recently, computerized memory trainings have been developed to target these biases, reducing rumination and lightening depressive symptoms. This

  5. Depression and Suicide Risk

    Science.gov (United States)

    Depression and Suicide Risk (2014) Definition: A mood disorder that causes a persistent feeling of sadness and ... i Prevalence: 1. Ranges of lifetime risk for depression: from 6.7% overall to 40% in men, ...

  6. Depression and Pregnancy

    Science.gov (United States)

    ... best live chat Live Help Fact Sheets Share Depression Thursday, 01 September 2016 In every pregnancy, a ... risk. This sheet talks about whether exposure to depression may increase the risk for birth defects over ...

  7. Heart disease and depression

    Science.gov (United States)

    ... gov/ency/patientinstructions/000790.htm Heart disease and depression To use the sharing features on this page, ... a heart attack or heart surgery Signs of Depression It is pretty common to feel down or ...

  8. Learning about depression

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000325.htm Learning about depression To use the sharing features on this page, ... trigger or reason. What are the Signs of Depression? You may notice some or all of the ...

  9. Depression - stopping your medicines

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000570.htm Depression - stopping your medicines To use the sharing features ... prescription medicines you may take to help with depression, anxiety, or pain. Like any medicine, there are ...

  10. Depression and Pregnancy

    Science.gov (United States)

    ... best live chat Live Help Fact Sheets Share Depression Thursday, 01 September 2016 In every pregnancy, a ... risk. This sheet talks about whether exposure to depression may increase the risk for birth defects over ...

  11. Depression Disturbs Germany

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The suicide of Robert Enke,the goalkeeper of the Germany national football team who had battled depression for years,stunned the country and cast depression into the national spotlight as a disturbing disease.

  12. Cortical hierarchy governs rat claustrocortical circuit organization.

    Science.gov (United States)

    White, Michael G; Cody, Patrick A; Bubser, Michael; Wang, Hui-Dong; Deutch, Ariel Y; Mathur, Brian N

    2017-04-15

    The claustrum is a telencephalic gray matter structure with various proposed functions, including sensory integration and attentional allocation. Underlying these concepts is the reciprocal connectivity of the claustrum with most, if not all, areas of the cortex. What remains to be elucidated to inform functional hypotheses further is whether a pattern exists in the strength of connectivity between a given cortical area and the claustrum. To this end, we performed a series of retrograde neuronal tract tracer injections into rat cortical areas along the cortical processing hierarchy, from primary sensory and motor to frontal cortices. We observed that the number of claustrocortical projections increased as a function of processing hierarchy; claustrum neurons projecting to primary sensory cortices were scant and restricted in distribution across the claustrum, whereas neurons projecting to the cingulate cortex were densely packed and more evenly distributed throughout the claustrum. This connectivity pattern suggests that the claustrum may preferentially subserve executive functions orchestrated by the cingulate cortex. J. Comp. Neurol. 525:1347-1362, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  13. Preventing Depression in Adults With Subthreshold Depression

    DEFF Research Database (Denmark)

    Buntrock, Claudia; Berking, Matthias; Smit, Filip

    2017-01-01

    BACKGROUND: Psychological interventions for the prevention of depression might be a cost-effective way to reduce the burden associated with depressive disorders. OBJECTIVE: To evaluate the cost-effectiveness of a Web-based guided self-help intervention to prevent major depressive disorder (MDD......) in people with subthreshold depression (sD). METHODS: A pragmatic randomized controlled trial was conducted with follow-up at 12 months. Participants were recruited from the general population via a large statutory health insurance company and an open access website. Participants were randomized to a Web......-based guided self-help intervention (ie, cognitive-behavioral therapy and problem-solving therapy assisted by supervised graduate students or health care professionals) in addition to usual care or to usual care supplemented with Web-based psycho-education (enhanced usual care). Depression-free years (DFYs...

  14. Analysis of BER Performance of the Spread Spectrum Communication System with Constrained Spreading Code

    OpenAIRE

    長谷川, 孝明; 羽渕, 裕真

    1996-01-01

    Copyright notice. c1996 IEICE All rights reserved. "Analysis of BER Performance of the Spread Spectrum Communication System with Constrained Spreading Code"Hiromasa HABUCHI, Toshio TAKEBAYASHI, Takaaki HASEGAWA. IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences ,1996 Vol.E79-A No.12 pp. 2078-2080 許諾No.07RB0055.

  15. Depression in cerebrovascular diseases

    OpenAIRE

    Voskresenskaya, Tatyana

    2009-01-01

    The paper discusses the topical problem of depression in cerebrovascular diseases. It shows its possible causes, mechanisms of occurrence, clinical picture and negative impact on the course of cerebrovascular disease and recovery of neurological functions. There is a bilateral association between stroke and depression: on the one hand, stroke is a risk factor for the development of depression and, on the other, depression is a both direct and indirect risk factor for the development of stroke...

  16. [Multiple mechanisms of depression].

    Science.gov (United States)

    Liu, Chun-Lin; Ruan, Ke-Feng; Gao, Jun-Wei; Wu, Fei; Zhang, Ji-Quan

    2013-08-01

    Depression is a grievous mental disease with an increasing high morbidity year by year and a serious social harm. The pathogenesises of depression is complicated and involves with multi-mechanisms and multi-organs. Recent studies demondtrate that in the nerval system and endocrine system there are many types of neurotransmitters and hormones, as well as their receptors, involved in depression. This paper reviews the research progress of depression in recent years.

  17. Method of treating depression

    Energy Technology Data Exchange (ETDEWEB)

    Henn, Fritz

    2013-04-09

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  18. Method of treating depression

    Science.gov (United States)

    Henn, Fritz [East Patchogue, NY

    2012-01-24

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  19. Spreading of Ultrarelativistic Wave Packet and Redshift

    CERN Document Server

    Lev, Felix M

    2012-01-01

    The red shift of light coming to the Earth from distant objects is usually explained as a consequence of the fact that the Universe is expanding. Such an explanation implies that photons emitted by distant objects travel in the interstellar medium practically without interaction with interstellar matter and hence they can survive their long journey to the Earth. We analyze this assumption by considering wave-packet spreading for an ultrarelativistic particle. We derive a formula which shows that spreading in the direction perpendicular to the particle momentum is very important and cannot be neglected. The implications of the results are discussed.

  20. Origin and turbulence spreading of plasma blobs

    Energy Technology Data Exchange (ETDEWEB)

    Manz, P.; Birkenmeier, G.; Stroth, U. [Physik-Department E28, Technische Universität München, James-Franck. Str. 1, Garching (Germany); Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, Garching (Germany); Ribeiro, T. T.; Scott, B. D.; Carralero, D.; Müller, S. H.; Müller, H. W.; Wolfrum, E. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, Garching (Germany); Fuchert, G. [IJL, Université de Lorraine, CNRS (UMR 7198), BP 40239, Vandoeuvre-lès-Nancy (France)

    2015-02-15

    The formation of plasma blobs is studied by analyzing their trajectories in a gyrofluid simulation in the vicinity of the separatrix. Most blobs arise at the maximum radial electric field outside the separatrix. In general, blob generation is not bound to one particular radial position or instability. A simple model of turbulence spreading for the scrape-off layer is derived. The simulations show that the blob dynamics can be represented by turbulence spreading, which constitutes a substantial energy drive for far scrape-off layer turbulence and is a more suitable quantity to study blob generation compared to the skewness.

  1. Technique for Controlling Spread of Limnotic Oncomelania

    Institute of Scientific and Technical Information of China (English)

    Li Damei(李大美); WANG Xiangsan(王祥三); LAI Yonggen

    2003-01-01

    Schistosomiasis is a parasitic disease mostly found in areas along the Changjiang River of China. The disease is spread solely through an intermediary named oncomelania, so its spread of schistosomiasis can be controlled by properly designing water intakes which prevent oncomelania from entering fanning land or residential areas. This paper reports a successful design process and a new oncomelania-free intake device. The design of the new intake is based on a sound research program in which extensive experimental studies were carried out to gain knowledge of oncomelania eco-hydraulic behavior and detailed flow field information through CFD simulation.

  2. Burstiness and spreading on temporal networks

    CERN Document Server

    Lambiotte, Renaud; Delvenne, Jean-Charles

    2013-01-01

    We discuss how spreading processes on temporal networks are impacted by the shape of their inter-event time distributions. Through simple mathematical arguments and toy examples, we find that the key factor is the ordering in which events take place, a property that tends to be affected by the bulk of the distributions and not only by their tail, as usually considered in the literature. We show that a detailed modeling of the temporal patterns observed in complex networks can change dramatically the properties of a spreading process, such as the ergodicity of a random walk process or the persistence of an epidemic.

  3. Clinical Judgments of Depression.

    Science.gov (United States)

    Jackson, Douglas N.; And Others

    1986-01-01

    Investigated degree to which judges could simulate Basic Personality Inventory (BPI) responses of a clinically depressed patient group. Judgmental profiles of depressed patients indicated very high reliabilities across information conditions, a high association with actual profiles of clinically depressed patients, and differentiation from other…

  4. Depression (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Depression KidsHealth > For Parents > Depression A A A What's ... to Help en español Comprender la depresión About Depression It's normal for kids to feel sad, down, ...

  5. Handling Depression | Smokefree 60+

    Science.gov (United States)

    Everyone feels blue now and then. It's a part of life. But if your feelings last more than few days and interfere with your normal daily activities, you may be suffering from depression. On this page: Symptoms of depression Who gets depressed and why?

  6. Depression and Aging.

    Science.gov (United States)

    Hamilton, Marshall, Ed.

    1982-01-01

    Contains four articles related to depression and aging. Compares normal adults with those having a major depressive disorder. Focuses on life satisfaction in the elderly, describing an individualized measure of life satisfaction. Describes similarities and differences between grief and depression. Contains a psychometric analysis of the Zung…

  7. Depression (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Depression KidsHealth > For Parents > Depression Print A A A ... to Help en español Comprender la depresión About Depression It's normal for kids to feel sad, down, ...

  8. Measuring psychotic depression

    DEFF Research Database (Denmark)

    Østergaard, Søren Dinesen; Meyers, B S; Flint, A J

    Psychotic depression (PD) is a highly debilitating condition, which needs intensive monitoring. However, there is no established rating scale for evaluating the severity of PD. The aim of this analysis was to assess the psychometric properties of established depression rating scales and a number...... of new composite rating scales, covering both depressive and psychotic symptoms, in relation to PD....

  9. Measuring psychotic depression

    DEFF Research Database (Denmark)

    Østergaard, Søren Dinesen; Meyers, B S; Flint, A J

    Psychotic depression (PD) is a highly debilitating condition, which needs intensive monitoring. However, there is no established rating scale for evaluating the severity of PD. The aim of this analysis was to assess the psychometric properties of established depression rating scales and a number...... of new composite rating scales, covering both depressive and psychotic symptoms, in relation to PD....

  10. Therapeutics of postpartum depression.

    Science.gov (United States)

    Thomson, Michael; Sharma, Verinder

    2017-05-01

    Postpartum depression is a prevalent disorder affecting many women of reproductive age. Despite increasing public awareness, it is frequently underdiagnosed and undertreated leading to significant maternal morbidity and adverse child outcomes. When identified, postpartum depression is usually treated as major depressive disorder. Many studies have identified the postpartum as a period of high risk for first presentations and relapses of bipolar disorder. Areas covered: This article reviews the acute and prophylactic treatment of postpartum major depressive disorder, bipolar depression and major depressive disorder with mixed features. The safety of antidepressant and mood stabilizing medications in pregnancy and breastfeeding will also be reviewed. Expert commentary: Differentiating postpartum major depressive disorder and postpartum bipolar depression can be difficult given their clinical similarities but accurate identification is vital for initiating proper treatment. Antidepressants are the mainstay of drug treatment for postpartum major depressive disorder, yet randomized controlled trials have shown conflicting results. A paucity of evidence exists for the effectiveness of antidepressant prophylaxis in the prevention of recurrences of major depressive disorder. Mood stabilizing medications reduce the risk of postpartum bipolar depression relapse but no randomized controlled trials have examined their use in the acute or prophylactic treatment of postpartum bipolar depression.

  11. Neurodynamics of somatosensory cortices studied by magnetoencephelography.

    Science.gov (United States)

    Kishida, Kuniharu

    2013-09-01

    From the viewpoint of statistical inverse problems, identification of transfer functions in feedback models is applied for neurodynamics of somatosensory cortices, and brain communication among active regions can be expressed in terms of transfer functions. However, brain activities have been investigated mainly by averaged waveforms in the conventional magnetoencephalography analysis, and thus brain communication among active regions has not yet been identified. It is shown that brain communication among two more than three brain regions is determined, when fluctuations related to concatenate averaged waveforms can be obtained by using a suitable blind source separation method. In blind identification of feedback model, some transfer functions or their impulse responses between output variables of current dipoles corresponding to active regions are identified from reconstructed time series data of fluctuations by the method of inverse problem. Neurodynamics of somatosensory cortices in 5 Hz median nerve stimuli can be shown by cerebral communication among active regions of somatosensory cortices in terms of impulse responses of feedback model.

  12. Importance of Depression in Diabetes.

    Science.gov (United States)

    Lustman, Patrick J.; Clouse, Ray E.; Anderson, Ryan J.

    Depression doubles the likelihood of comorbid depression, which presents as major depression in 11% and subsyndromal depression in 31% of patients with the medical illness. The course of depression is chronic, and afflicted patients suffer an average of one episode annually. Depression has unique importance in diabetes because of its association…

  13. Sex Differences in the Relationship Between Conduct Disorder and Cortical Structure in Adolescents.

    Science.gov (United States)

    Smaragdi, Areti; Cornwell, Harriet; Toschi, Nicola; Riccelli, Roberta; Gonzalez-Madruga, Karen; Wells, Amy; Clanton, Roberta; Baker, Rosalind; Rogers, Jack; Martin-Key, Nayra; Puzzo, Ignazio; Batchelor, Molly; Sidlauskaite, Justina; Bernhard, Anka; Martinelli, Anne; Kohls, Gregor; Konrad, Kerstin; Baumann, Sarah; Raschle, Nora; Stadler, Christina; Freitag, Christine; Sonuga-Barke, Edmund J S; De Brito, Stephane; Fairchild, Graeme

    2017-08-01

    Previous studies have reported reduced cortical thickness and surface area and altered gyrification in frontal and temporal regions in adolescents with conduct disorder (CD). Although there is evidence that the clinical phenotype of CD differs between males and females, no studies have examined whether such sex differences extend to cortical and subcortical structure. As part of a European multisite study (FemNAT-CD), structural magnetic resonance imaging (MRI) data were collected from 48 female and 48 male participants with CD and from 104 sex-, age-, and pubertal-status-matched controls (14-18 years of age). Data were analyzed using surface-based morphometry, testing for effects of sex, diagnosis, and sex-by-diagnosis interactions, while controlling for age, IQ, scan site, and total gray matter volume. CD was associated with cortical thinning and higher gyrification in ventromedial prefrontal cortex in both sexes. Males with CD showed lower, and females with CD showed higher, supramarginal gyrus cortical thickness compared with controls. Relative to controls, males with CD showed higher gyrification and surface area in superior frontal gyrus, whereas the opposite pattern was seen in females. There were no effects of diagnosis or sex-by-diagnosis interactions on subcortical volumes. Results are discussed with regard to attention-deficit/hyperactivity disorder, depression, and substance abuse comorbidity, medication use, handedness, and CD age of onset. We found both similarities and differences between males and females in CD-cortical structure associations. This initial evidence that the pathophysiological basis of CD may be partly sex-specific highlights the need to consider sex in future neuroimaging studies and suggests that males and females may require different treatments. Copyright © 2017 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  14. GABAA-benzodiazepine receptor availability in smokers and nonsmokers: relationship to subsyndromal anxiety and depression.

    Science.gov (United States)

    Esterlis, Irina; Cosgrove, Kelly P; Batis, Jeffery C; Bois, Frederic; Kloczynski, Tracy A; Stiklus, Stephanie M; Perry, Edward; Tamagnan, Gilles D; Seibyl, John P; Makuch, Robert; Krishnan-Sarin, Suchitra; O'Malley, Stephanie; Staley, Julie K

    2009-12-01

    Many smokers experience subsyndromal anxiety symptoms while smoking and during acute abstinence, which may contribute to relapse. We hypothesized that cortical gamma aminobutyric acid(A)-benzodiazepine receptor (GABA(A)-BZR) availability in smokers and nonsmokers might be related to the expression of subsyndromal anxiety, depressive, and pain symptoms. Cortical GABA(A)-BZRs were imaged in 15 smokers (8 men and 7 women), and 15 healthy age and sex-matched nonsmokers, and 4 abstinent tobacco smokers (3 men; 1 woman) using [(123)I]iomazenil and single photon emission computed tomography (SPECT). Anxiety and depressive symptoms were measured using the Spielberger's State-Trait Anxiety Index (STAI) and the Center for Epidemiology Scale for Depressive Symptoms (CES-D). The cold pressor task was administered to assess pain tolerance and sensitivity. The relationship between cortical GABA(A)-BZR availability, smoking status, and subsyndromal depression and anxiety symptoms, as well as pain tolerance and sensitivity, were evaluated. Surprisingly, there were no statistically significant differences in overall GABA(A)-BZR availability between smokers and nonsmokers or between active and abstinent smokers; however, cortical GABA(A)-BZR availability negatively correlated with subsyndromal state anxiety symptoms in nonsmokers but not in smokers. In nonsmokers, the correlation was seen across many brain areas with state anxiety [parietal (r = -0.47, P = 0.03), frontal (r = -0.46, P = 0.03), anterior cingulate (r = -0.47, P = 0.04), temporal (r = -0.47, P = 0.03), occipital (r = -0.43, P = 0.05) cortices, and cerebellum (r = -0.46, P = 0.04)], trait anxiety [parietal (r = -0.72, P = 0.02), frontal (r = -0.72, P = 0.02), and occipital (r = -0.65, P = 0.04) cortices] and depressive symptoms [parietal (r = -0.68; P = 0.02), frontal (r = -0.65; P = 0.03), anterior cingulate (r = -0.61; P = 0.04), and temporal (r = -0.66; P = 0.02) cortices]. The finding that a similar relationship

  15. The ontogeny of the cortical language network.

    Science.gov (United States)

    Skeide, Michael A; Friederici, Angela D

    2016-05-01

    Language-processing functions follow heterogeneous developmental trajectories. The human embryo can already distinguish vowels in utero, but grammatical complexity is usually not fully mastered until at least 7 years of age. Examining the current literature, we propose that the ontogeny of the cortical language network can be roughly subdivided into two main developmental stages. In the first stage extending over the first 3 years of life, the infant rapidly acquires bottom-up processing capacities, which are primarily implemented bilaterally in the temporal cortices. In the second stage continuing into adolescence, top-down processes emerge gradually with the increasing functional selectivity and structural connectivity of the left inferior frontal cortex.

  16. Rasmussen's encephalitis presenting as focal cortical dysplasia

    Directory of Open Access Journals (Sweden)

    D.J. O'Rourke

    2014-01-01

    Full Text Available Rasmussen's encephalitis is a rare syndrome characterized by intractable seizures, often associated with epilepsia partialis continua and symptoms of progressive hemispheric dysfunction. Seizures are usually the hallmark of presentation, but antiepileptic drug treatment fails in most patients and is ineffective against epilepsia partialis continua, which often requires surgical intervention. Co-occurrence of focal cortical dysplasia has only rarely been described and may have implications regarding pathophysiology and management. We describe a rare case of dual pathology of Rasmussen's encephalitis presenting as a focal cortical dysplasia (FCD and discuss the literature on this topic.

  17. Cortical activation elicited by unrecognized stimuli

    Directory of Open Access Journals (Sweden)

    Badgaiyan Rajendra D

    2006-05-01

    Full Text Available Abstract Background It is unclear whether a stimulus that cannot be recognized consciously, could elicit a well-processed cognitive response. Methods We used functional imaging to examine the pattern of cortical activation elicited by unrecognized stimuli during memory processing. Subjects were given a recognition task using recognizable and non-recognizable subliminal stimuli. Results Unrecognized stimuli activated the cortical areas that are associated with retrieval attempt (left prefrontal, and novelty detection (left hippocampus. This indicates that the stimuli that were not consciously recognized, activated neural network associated with aspects of explicit memory processing. Conclusion Results suggest that conscious recognition of stimuli is not necessary for activation of cognitive processing.

  18. Elemental mercury poisoning probably causes cortical myoclonus.

    Science.gov (United States)

    Ragothaman, Mona; Kulkarni, Girish; Ashraf, Valappil V; Pal, Pramod K; Chickabasavaiah, Yasha; Shankar, Susarla K; Govindappa, Srikanth S; Satishchandra, Parthasarthy; Muthane, Uday B

    2007-10-15

    Mercury toxicity causes postural tremors, commonly referred to as "mercurial tremors," and cerebellar dysfunction. A 23-year woman, 2 years after injecting herself with elemental mercury developed disabling generalized myoclonus and ataxia. Electrophysiological studies confirmed the myoclonus was probably of cortical origin. Her deficits progressed over 2 years and improved after subcutaneous mercury deposits at the injection site were surgically cleared. Myoclonus of cortical origin has never been described in mercury poisoning. It is important to ask patients presenting with jerks about exposure to elemental mercury even if they have a progressive illness, as it is a potentially reversible condition as in our patient.

  19. Posterior cortical atrophy: a brief review.

    Science.gov (United States)

    Kirshner, Howard S; Lavin, Patrick J M

    2006-11-01

    Posterior cortical atrophy is a striking clinical syndrome in which a dementing illness begins with visual symptoms. Initially, the problem may seem to be loss of elementary vision, but over time the patient develops features of visual agnosia, topographical difficulty, optic ataxia, simultanagnosia, ocular apraxia (Balint's syndrome), alexia, acalculia, right-left confusion, and agraphia (Gerstmann's syndrome), and later a more generalized dementia. Occasional patients have visual hallucinations and signs of Parkinson's disease or Lewy body dementia. A number of different neuropathologic disorders are associated with posterior cortical atrophy.

  20. Relativistic suppression of wave packet spreading.

    Science.gov (United States)

    Su, Q; Smetanko, B; Grobe, R

    1998-03-30

    We investigate numerically the solution of Dirac equation and analytically the Klein-Gordon equation and discuss the relativistic motion of an electron wave packet in the presence of an intense static electric field. In contrast to the predictions of the (non-relativistic) Schroedinger theory, the spreading rate in the field's polarization direction as well as in the transverse directions is reduced.

  1. Hiding Single Photons With Spread Spectrum Technology

    CERN Document Server

    Belthangady, Chinmay; Yu, Ite A; Yin, G Y; Kahn, J M; Harris, S E

    2010-01-01

    We describe a proof-of-principal experiment demonstrating the use of spread spectrum technology at the single photon level. We show how single photons with a prescribed temporal shape, in the presence of interfering noise, may be hidden and recovered.

  2. Modeling and simulation of epidemic spread

    DEFF Research Database (Denmark)

    Shatnawi, Maad; Lazarova-Molnar, Sanja; Zaki, Nazar

    2013-01-01

    and control such epidemics. This paper presents an overview of the epidemic spread modeling and simulation, and summarizes the main technical challenges in this field. It further investigates the most relevant recent approaches carried out towards this perspective and provides a comparison and classification...

  3. Restricted spread of tomato spotted wilt virus

    NARCIS (Netherlands)

    Maris, P.C.; Joosten, N.N.; Goldbach, R.W.; Peters, D.

    2003-01-01

    Spread of Tomato spotted wilt virus (TSWV) and population development of its vector Frankliniella occidentalis were studied on the pepper accessions CPRO-1 and Pikante Reuzen, which are resistant and susceptible to thrips, respectively. Viruliferous thrips were released on plants of each accession (

  4. Damage spreading on networks: Clustering effects

    Indian Academy of Sciences (India)

    Z Z Guo; Xiao-Wei Wu; Chun-An Wang

    2007-04-01

    The damage spreading of the Ising model on three kinds of networks is studied with Glauber dynamics. One of the networks is generated by evolving the hexagonal lattice with the star-triangle transformation. Another kind of network is constructed by connecting the midpoints of the edges of the topological hexagonal lattice. With the evolution of these structures, damage spreading transition temperature increases and a general explanation for this phenomenon is presented from the view of the network. The relationship between the transition temperature and the network measure-clustering coefficient is set up and it is shown that the increase of damage spreading transition temperature is the result of more and more clustering of the network. We construct the third kind of network-random graphs with Poisson degree distributions by changing the average degree of the network. We show that the increase in the average degree is equivalent to the clustering of nodes and this leads to the increase in damage spreading transition temperature.

  5. Social distancing strategies against disease spreading

    Science.gov (United States)

    Valdez, L. D.; Buono, C.; Macri, P. A.; Braunstein, L. A.

    2014-03-01

    The recurrent infectious diseases and their increasing impact on the society has promoted the study of strategies to slow down the epidemic spreading. In this review we outline the applications of percolation theory to describe strategies against epidemic spreading on complex networks. We give a general outlook of the relation between link percolation and the susceptible-infected-recovered model, and introduce the node void percolation process to describe the dilution of the network composed by healthy individual, i.e, the network that sustain the functionality of a society. Then, we survey two strategies: the quenched disorder strategy where an heterogeneous distribution of contact intensities is induced in society, and the intermittent social distancing strategy where health individuals are persuaded to avoid contact with their neighbors for intermittent periods of time. Using percolation tools, we show that both strategies may halt the epidemic spreading. Finally, we discuss the role of the transmissibility, i.e, the effective probability to transmit a disease, on the performance of the strategies to slow down the epidemic spreading.

  6. Spread of Rare Fungus from Vancouver Island

    Centers for Disease Control (CDC) Podcasts

    2006-12-20

    Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism.  Created: 12/20/2006 by Emerging Infectious Diseases.   Date Released: 12/29/2006.

  7. Energy spread in plasma-based acceleration

    NARCIS (Netherlands)

    Reitsma, A.; Trines, R.; Goloviznin, V.

    2000-01-01

    Electron acceleration in a one-dimensional plasma wave has been simulated, with emphasis on minimizing the energy spread of an accelerated electron bunch, while keeping the mean energy gain at a reasonable level. Bunch length, beam loading, and the injection phase are tuned to reach this goal. The s

  8. Optimization of network protection against virus spread

    NARCIS (Netherlands)

    Gourdin, E.; Omic, J.; Van Mieghem, P.

    2011-01-01

    The effect of virus spreading in a telecommunication network, where a certain curing strategy is deployed, can be captured by epidemic models. In the N-intertwined model proposed and studied in [1], [2], the probability of each node to be infected depends on the curing and infection rate of its neig

  9. Experiments in water spreading at Newark, Delaware

    Science.gov (United States)

    Boggess, Durward Haye; Rima, Donald Robert

    1962-01-01

    Two experiments in water spreading were made at Newark, Del., to evaluate the prospects of using excess storm runoff to recharge the shallow water-table aquifer which serves the community. Water was diverted from 1 of the city's 3 production wells and released into an infiltration ditch near the municipal well field. Although slightly more than 65,000 cubic feet of water (nearly 500,000 gallons ) was spread in the infiltration ditch and allowed to seep into the subsurface, there was no indication that any appreciable amount of water reached the producing aquifer. Instead, a perched zone of saturation was created by the presence of an impermeable or slightly permeable bed above the water table. So effective is this barrier to the downward movement of water that within a period of less than 1 day, the apex of the perched zone rose about 10 feet to the level of the bottom of the infiltration ditch. As more water was added, the mound of saturation spread laterally. On the basis of these experiments, it appears that the principal aquifer at Newark, Del., would not be benefited by spreading water in shallow infiltration ditches or basins. However, the absorptive capacity of the unsaturated materials which occur at a shallow depth, is sufficient to permit the disposal of large volumes of storm runoff.

  10. Centerfolds: Your Newspaper's Most Exciting Spreads

    Science.gov (United States)

    Quevedo, Jose

    1977-01-01

    Gives guidelines for planning copy and design for the centerfold spread of a newspaper in order to use this natural display section to enhance the overall interest of the newspaper. Shows how college and professional papers have used centerfolds effectively. (GW)

  11. ParB spreading requires DNA bridging

    NARCIS (Netherlands)

    Graham, Thomas G. W.; Wang, Xindan; Song, Dan; Etson, Candice M.; van Oijen, Antoine M.; Rudner, David Z.; Loparo, Joseph J.

    2014-01-01

    The parABS system is a widely employed mechanism for plasmid partitioning and chromosome segregation in bacteria. ParB binds to parS sites on plasmids and chromosomes and associates with broad regions of adjacent DNA, a phenomenon known as spreading. Although essential for ParB function, the mechani

  12. DataSpread: Unifying Databases and Spreadsheets.

    Science.gov (United States)

    Bendre, Mangesh; Sun, Bofan; Zhang, Ding; Zhou, Xinyan; Chang, Kevin ChenChuan; Parameswaran, Aditya

    2015-08-01

    Spreadsheet software is often the tool of choice for ad-hoc tabular data management, processing, and visualization, especially on tiny data sets. On the other hand, relational database systems offer significant power, expressivity, and efficiency over spreadsheet software for data management, while lacking in the ease of use and ad-hoc analysis capabilities. We demonstrate DataSpread, a data exploration tool that holistically unifies databases and spreadsheets. It continues to offer a Microsoft Excel-based spreadsheet front-end, while in parallel managing all the data in a back-end database, specifically, PostgreSQL. DataSpread retains all the advantages of spreadsheets, including ease of use, ad-hoc analysis and visualization capabilities, and a schema-free nature, while also adding the advantages of traditional relational databases, such as scalability and the ability to use arbitrary SQL to import, filter, or join external or internal tables and have the results appear in the spreadsheet. DataSpread needs to reason about and reconcile differences in the notions of schema, addressing of cells and tuples, and the current "pane" (which exists in spreadsheets but not in traditional databases), and support data modifications at both the front-end and the back-end. Our demonstration will center on our first and early prototype of the DataSpread, and will give the attendees a sense for the enormous data exploration capabilities offered by unifying spreadsheets and databases.

  13. Spreading of Excellence in Serious Gaming

    NARCIS (Netherlands)

    Westera, Wim; Berta, Riccardo; Moreno-Ger, Pablo; Bellotti, Francesco; Nadolski, Rob; Padrón-Nápoles, Carmen Luisa; Boyle, Liz; Beligan, Daniel; Baalsrud Hauge, Jannicke

    2014-01-01

    Westera, W., Berta, R., Moreno-Ger, P., Bellotti, F., Nadolski, R., Padrón-Nápoles, C. L., Boyle, L., Beligan, D., & Baalsrud Hauge, J. (2013, December 12). Spreading of Excellence in Serious Gaming. Presentation on the GALA project review meeting. Luxembourg: European Commission.

  14. Natural Spread of Plant Viruses by Birds

    NARCIS (Netherlands)

    Peters, D.; Engels, C.; Sarra, S.

    2012-01-01

    Observations made in Mali strongly suggest that Rice yellow mottle virus (RYMV) is spread by weaverbirds (Quelea quelea) below and around baobab trees (Adansonia digitata) in which they nest. Rice leaves in bird nests appeared to be infected. In Spain, an infection of Southern bean mosaic virus (SBM

  15. Experiments and modelling on vertical flame spread

    Energy Technology Data Exchange (ETDEWEB)

    Keski-Rahkonen, O.; Mangs, J. [VTT Building and Transport, Espoo (Finland)

    2004-07-01

    he principle and some preliminary results are shown of a new vertical flame spread modelling effort. Quick experimental screenings on relevant phenomena are made, some models are evaluated, and a new set of needed measuring instruments is proposed. Finally a single example of FRNC cable is shown as application of the methods. (orig.)

  16. Turbulence spreading in gyro-kinetic theory

    Science.gov (United States)

    Migliano, P.; Buchholz, R.; Grosshauser, S. R.; Hornsby, W. A.; Peeters, A. G.; Stauffert, O.

    2016-01-01

    In this letter a new operative definition for the turbulence intensity in connection with magnetized plasmas is given. In contrast to previous definitions the new definition satisfies a Fisher-Kolmogorov-Petrovskii-Piskunov type equation. Furthermore, explicit expressions for the turbulence intensity and the turbulence intensity flux, that allow for the first time direct numerical evaluation, are derived. A carefully designed numerical experiment for the case of a tokamak is performed to study the impact of turbulence spreading. The effective turbulence diffusion coefficient is measured to be smaller than the heat conduction coefficient and the turbulence spreading length is found to be of the order of the turbulence correlation length. The results show that turbulence spreading can play a role in the non-local flux gradient relation, or in the scaling of transport coefficients with the normalized Larmor radius, only over lengths scale of the order of the turbulence correlation length. A new turbulence convection mechanism, due to the drift connected with the magnetic field inhomogeneities, is described. The convective flux integrates to zero under the flux surface average unless there is an up-down asymmetry in the tubulence intensity. The latter asymmetry can be generated through a radial inhomogeneity or plasma rotation. It is shown that the turbulence convection can lead to a spreading of the order of the correlation length.

  17. Spreading of water nanodroplets on graphene

    Science.gov (United States)

    Andrews, Joseph; Sinha, Shayandev; Chung, Peter; Das, Siddhartha

    Understanding the wetting of 2D materials is central to the successful application of these materials in a variety of disciplines that involve the interaction of a liquid with such layered substrates. Recent studies focusing on wetting statics and contact angle selection on graphene-coated solids indicate a wetting translucent behavior of graphene. However, little research has been done on the wetting dynamics of graphene-coated systems. Here, we simulate the wetting dynamics of water drops on free-standing graphene layers using a molecular dynamics framework. We employ the extended simple point charge (SPC/E) model to simulate the water drops. Our simulations are validated against the experimental results of water drop contact angles on graphite. Unlike many existing MD studies, we obtain the results starting from a physical consideration of spherical water drops. We observe the half power law for the spreading dynamics, i.e., r~t(1/2) (r is the spreading radius and t is the spreading time). Identical spreading laws have been identified for Lennard Jones (LJ) nanodroplets on non-layered surfaces; therefore, we establish that the change in the nature of the substrate (non-layered to 2D) and the liquid (LJ to water) does not alter the physics of wetting dynamics of nanodroplets.

  18. Spreading depolarization may link migraine and stroke.

    Science.gov (United States)

    Eikermann-Haerter, Katharina

    2014-01-01

    Migraine increases the risk of stroke, particularly in young and otherwise healthy adults. Being the most frequent neurological condition, migraine prevalence is on a par with that of other common stroke risk factors, such as diabetes or hypertension. Several patterns of association have emerged: (1) migraine and stroke share a common association (eg, vasculopathies, patent foramen ovale, or pulmonary A-V malformations); (2) injury to the arterial wall such as acute arterial dissections can present as migraine aura attacks or stroke; (3) strokes rarely develop during a migraine attack, as described for "migrainous stroke." Increasing experimental evidence suggests that cerebral hyperexcitability and enhanced susceptibility to spreading depolarization, the electrophysiologic event underlying migraine, may serve as a mechanism underlying the migraine-stroke association. Mice carrying human vascular or neuronal migraine mutations exhibit an enhanced susceptibility to spreading depolarization while being particularly vulnerable to cerebral ischemia. The severe stroke phenotype in migraine mutant mice can be prevented by suppressing spreading depolarization. If confirmed in the clinical setting, inhibiting spreading depolarization might protect migraineurs at stroke risk as well as decrease attacks of migraine. © 2014 American Headache Society.

  19. Spreading of Excellence in Serious Gaming

    NARCIS (Netherlands)

    Westera, Wim; Berta, Riccardo; Moreno-Ger, Pablo; Bellotti, Francesco; Nadolski, Rob; Padrón-Nápoles, Carmen Luisa; Boyle, Liz; Beligan, Daniel; Baalsrud Hauge, Jannicke

    2014-01-01

    Westera, W., Berta, R., Moreno-Ger, P., Bellotti, F., Nadolski, R., Padrón-Nápoles, C. L., Boyle, L., Beligan, D., & Baalsrud Hauge, J. (2013, December 12). Spreading of Excellence in Serious Gaming. Presentation on the GALA project review meeting. Luxembourg: European Commission.

  20. Modelling of fire spread in car parks

    NARCIS (Netherlands)

    Noordijk, L.M.; Lemaire, A.D.

    2005-01-01

    Currently, design codes assume that in a car park fire at most 3-4 vehicles are on fire at the same time. Recent incidents in car parks have drawn international attention to such assumptions and have raised questions as to the fire spreading mechanism and the resulting fire load on the structure.

  1. Understanding childhood depression.

    Science.gov (United States)

    Malhotra, Savita; Das, Partha Pratim

    2007-02-01

    Major depressive disorder in children is a severe and a chronically disabling disorder. This population appears to be a special group in terms of consequences of poor psychosocial and academic outcome and increased risk of substance abuse, and suicide. Studies have revealed several major findings in genetic, familial, psychological, and biological aspects of such depression, some of which have explored into the issue of its relationship with adult depression. Considerable advances have been made now in the area of childhood depression providing a better understanding of its nature. We review literature available on historical aspect, epidemiology, clinical characteristics, and aetiology of childhood depression.

  2. Independent measurement of femoral cortical thickness and cortical bone density using clinical CT.

    Science.gov (United States)

    Treece, G M; Gee, A H

    2015-02-01

    The local structure of the proximal femoral cortex is of interest since both fracture risk, and the effects of various interventions aimed at reducing that risk, are associated with cortical properties focused in particular regions rather than dispersed over the whole bone. Much of the femoral cortex is less than 3mm thick, appearing so blurred in clinical CT that its actual density is not apparent in the data, and neither thresholding nor full-width half-maximum techniques are capable of determining its width. Our previous work on cortical bone mapping showed how to produce more accurate estimates of cortical thickness by assuming a fixed value of the cortical density for each hip. However, although cortical density varies much less over the proximal femur than thickness, what little variation there is leads to errors in thickness measurement. In this paper, we develop the cortical bone mapping technique by exploiting local estimates of imaging blur to correct the global density estimate, thus providing a local density estimate as well as more accurate estimates of thickness. We also consider measurement of cortical mass surface density and the density of trabecular bone immediately adjacent to the cortex. Performance is assessed with ex vivo clinical QCT scans of proximal femurs, with true values derived from high resolution HRpQCT scans of the same bones. We demonstrate superior estimation of thickness than is possible with alternative techniques (accuracy 0.12 ± 0.39 mm for cortices in the range 1-3mm), and that local cortical density estimation is feasible for densities >800 mg/cm(3).

  3. Depression in geriatric patients.

    Science.gov (United States)

    Abbas Asghar-Ali, A; Braun, U K

    2009-02-01

    While the most serious of depressive illnesses in the elderly is major depressive disorder, patients' quality of life can be significantly impacted by dysthmic disorder, sub-threshold depression (minor depression), or a depressive disorder due to a general medical condition, all of which have been shown to be more prevalent than major depression in the community dwelling population of older adults. Older adults are also more likely to develop grief reaction and frequently deal with issues of bereavement. This review will discuss the diagnoses of all relevant depressive diagnoses that primary care physicians are likely to encounter. Among the many different assessment tools that screen for depression the briefest instruments are a two-question screening tool recommended by the U.S. Preventive Services Task Force and, specifically developed for older adults, the Geriatric Depression Scale (GDS) that is available in a short 15- Yes/No-question version. Many medical illnesses are associated with depressive symptoms. The focus in this review is on dementing illnesses/cerebrovascular disease, dementia of the Alzheimer's type, and Parkinson disease. First-line pharmacological therapy of depression includes selective serotonin inhibitors (SSRIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs). Side effects of particular drugs can often be geared towards achieving additional benefits, e.g. weight gain associated with the use of some SSRISs may be helpful for patients with dementia.

  4. Cerebrospinal fluid space alterations in melancholic depression.

    Directory of Open Access Journals (Sweden)

    Esther Via

    Full Text Available Melancholic depression is a biologically homogeneous clinical entity in which structural brain alterations have been described. Interestingly, reports of structural alterations in melancholia include volume increases in Cerebro-Spinal Fluid (CSF spaces. However, there are no previous reports of CSF volume alterations using automated whole-brain voxel-wise approaches, as tissue classification algorithms have been traditionally regarded as less reliable for CSF segmentation. Here we aimed to assess CSF volumetric alterations in melancholic depression and their clinical correlates by means of a novel segmentation algorithm ('new segment', as implemented in the software Statistical Parametric Mapping-SPM8, incorporating specific features that may improve CSF segmentation. A three-dimensional Magnetic Resonance Image (MRI was obtained from seventy patients with melancholic depression and forty healthy control subjects. Although imaging data were pre-processed with the 'new segment' algorithm, in order to obtain a comparison with previous segmentation approaches, tissue segmentation was also performed with the 'unified segmentation' approach. Melancholic patients showed a CSF volume increase in the region of the left Sylvian fissure, and a CSF volume decrease in the subarachnoid spaces surrounding medial and lateral parietal cortices. Furthermore, CSF increases in the left Sylvian fissure were negatively correlated with the reduction percentage of depressive symptoms at discharge. None of these results were replicated with the 'unified segmentation' approach. By contrast, between-group differences in the left Sylvian fissure were replicated with a non-automated quantification of the CSF content of this region. Left Sylvian fissure alterations reported here are in agreement with previous findings from non-automated CSF assessments, and also with other reports of gray and white matter insular alterations in depressive samples using automated approaches

  5. Depression in adolescence

    Science.gov (United States)

    Thapar, Anita; Collishaw, Stephan; Pine, Daniel S; Thapar, Ajay K

    2012-01-01

    Unipolar depressive disorder in adolescence is common worldwide but often unrecognised. The incidence, notably in girls, rises sharply after puberty and, by the end of adolescence, the 1 year prevalence rate exceeds 4%. The burden is highest in low-income and middle-income countries. Depression is associated with sub stantial present and future morbidity, and heightens suicide risk. The strongest risk factors for depression in adolescents are a family history of depression and exposure to psychosocial stress. Inherited risks, developmental factors, sex hormones, and psychosocial adversity interact to increase risk through hormonal factors and associated perturbed neural pathways. Although many similarities between depression in adolescence and depression in adulthood exist, in adolescents the use of antidepressants is of concern and opinions about clinical management are divided. Effective treatments are available, but choices are dependent on depression severity and available resources. Prevention strategies targeted at high-risk groups are promising. PMID:22305766

  6. [Depression and neurological diseases].

    Science.gov (United States)

    Piber, D; Hinkelmann, K; Gold, S M; Heesen, C; Spitzer, C; Endres, M; Otte, C

    2012-11-01

    In many neurological diseases a depressive syndrome is a characteristic sign of the primary disease or is an important comorbidity. Post-stroke depression, for example, is a common and relevant complication following ischemic brain infarction. Approximately 4 out of every 10 stroke patients develop depressive disorders in the course of the disease which have a disadvantageous effect on the course and the prognosis. On the other hand depression is also a risk factor for certain neurological diseases as was recently demonstrated in a meta-analysis of prospective cohort studies which revealed a much higher stroke risk for depressive patients. Furthermore, depression plays an important role in other neurological diseases with respect to the course and quality of life, such as Parkinson's disease, multiple sclerosis and epilepsy. This article gives a review of the most important epidemiological, pathophysiological and therapeutic aspects of depressive disorders as a comorbidity of neurological diseases and as a risk factor for neurological diseases.

  7. Phase diagram of epidemic spreading - unimodal vs. bimodal probability distributions

    CERN Document Server

    Lancic, Alen; Sikic, Mile; Stefancic, Hrvoje

    2009-01-01

    The disease spreading on complex networks is studied in SIR model. Simulations on empirical complex networks reveal two specific regimes of disease spreading: local containment and epidemic outbreak. The variables measuring the extent of disease spreading are in general characterized by a bimodal probability distribution. Phase diagrams of disease spreading for empirical complex networks are introduced. A theoretical model of disease spreading on m-ary tree is investigated both analytically and in simulations. It is shown that the model reproduces qualitative features of phase diagrams of disease spreading observed in empirical complex networks. The role of tree-like structure of complex networks in disease spreading is discussed.

  8. Spatiotemporal Dynamics of Cortical Representations during and after Stimulus Presentation

    Directory of Open Access Journals (Sweden)

    Marieke Esther van de Nieuwenhuijzen

    2016-05-01

    Full Text Available Visual perception is a spatiotemporally complex process. In this study, we investigated cortical dynamics during and after stimulus presentation. We observed that visual category information related to the difference between faces and objects became apparent in the occipital lobe after 63 ms. Within the next 110 ms, activation spread out to include the temporal lobe before returning to residing mainly in the occipital lobe again. After stimulus offset, a peak in information was observed, comparable to the peak after stimulus onset. Moreover, similar processes, albeit not identical, seemed to underlie both peaks. Information about the categorical identity of the stimulus remained present until 677 ms after stimulus offset, during which period the stimulus had to be retained in working memory. Activation patterns initially resembled those observed during stimulus presentation. After about 200 ms, however, this representation changed and class-specific activity became more equally distributed over the four lobes. These results show that, although there are common processes underlying stimulus representation both during and after stimulus presentation, these representations change depending on the specific stage of perception and maintenance.

  9. Depressive symptoms accelerate cognitive decline in amyloid-positive MCI patients

    Energy Technology Data Exchange (ETDEWEB)

    Brendel, Matthias; Xiong, Guoming; Delker, Andreas [University of Munich, Department of Nuclear Medicine, Munich (Germany); Pogarell, Oliver [University of Munich, Department of Psychiatry, Munich (Germany); Bartenstein, Peter; Rominger, Axel [University of Munich, Department of Nuclear Medicine, Munich (Germany); Munich Cluster for Systems Neurology (SyNergy), Munich (Germany); Collaboration: for the Alzheimer' s Disease Neuroimaging Initiative

    2015-04-01

    Late-life depression even in subsyndromal stages is strongly associated with Alzheimer's disease (AD). Furthermore, brain amyloidosis is an early biomarker in subjects who subsequently suffer from AD and can be sensitively detected by amyloid PET. Therefore, we aimed to compare amyloid load and glucose metabolism in subsyndromally depressed subjects with mild cognitive impairment (MCI). [{sup 18}F]AV45 PET, [{sup 18}F]FDG PET and MRI were performed in 371 MCI subjects from the Alzheimer's Disease Neuroimaging Initiative Subjects were judged β-amyloid-positive (Aβ+; 206 patients) or β-amyloid-negative (Aβ-; 165 patients) according to [{sup 18}F]AV45 PET. Depressive symptoms were assessed by the Neuropsychiatric Inventory Questionnaire depression item 4. Subjects with depressive symptoms (65 Aβ+, 41 Aβ-) were compared with their nondepressed counterparts. Conversion rates to AD were analysed (mean follow-up time 21.5 ± 9.1 months) with regard to coexisting depressive symptoms and brain amyloid load. Aβ+ depressed subjects showed large clusters with a higher amyloid load in the frontotemporal and insular cortices (p < 0.001) with coincident hypermetabolism (p < 0.001) in the frontal cortices than nondepressed subjects. Faster progression to AD was observed in subjects with depressive symptoms (p < 0.005) and in Aβ+ subjects (p < 0.001). Coincident depressive symptoms additionally shortened the conversion time in all Aβ+ subjects (p < 0.005) and to a greater extent in those with a high amyloid load (p < 0.001). Our results clearly indicate that Aβ+ MCI subjects with depressive symptoms have an elevated amyloid load together with relative hypermetabolism of connected brain areas compared with cognitively matched nondepressed individuals. MCI subjects with high amyloid load and coexistent depressive symptoms are at high risk of faster conversion to AD. (orig.)

  10. Developmental regulation of spatio-temporal patterns of cortical circuit activation

    Directory of Open Access Journals (Sweden)

    Trevor Charles Griffen

    2013-01-01

    Full Text Available Neural circuits are refined in an experience-dependent manner during early postnatal development. How development modulates the spatio-temporal propagation of activity through cortical circuits is poorly understood. Here we use voltage sensitive dye imaging (VSD to show that there are significant changes in the spatio-temporal patterns of intracortical signals in primary visual cortex from postnatal day 13 (P13, eye opening, to P28, the peak of the critical period for rodent visual cortical plasticity. Upon direct stimulation of layer 4 (L4, activity spreads to L2/3 and to L5 at all ages. However, while from eye opening to the peak of the critical period, the amplitude and persistence of the voltage signal decrease, peak activation is reached more quickly and the interlaminar gain increases with age. The lateral spread of activation within layers remains unchanged throughout the time window under analysis. These developmental changes in spatio-temporal patterns of intracortical circuit activation are mediated by differences in the contributions of excitatory and inhibitory synaptic components. Our results demonstrate that after eye opening the circuit in primary visual cortex is refined through a progression of changes that shape the spatio-temporal patterns of circuit activation. Signals become more efficiently propagated across layers through developmentally regulated changes in interlaminar gain.

  11. Familial cortical tremor with epilepsy and cerebellar pathological findings

    NARCIS (Netherlands)

    van Rootselaar, AF; Aronica, E; Steur, ENHJ; Rozemuller-Kwakkel, JM; de Vos, RAI; Tijssen, MAJ

    The clinical and neuropathological findings in a patient with familial cortical tremor with epilepsy (FCTE) are described. Clinically, the patient showed cortical myoclonus, tremor, and generalized seizures. Pathological investigation showed cerebellar degeneration and somal sprouting and loss of

  12. Relationship Between White Matter Hyperintensities, Cortical Thickness, and Cognition

    NARCIS (Netherlands)

    Tuladhar, Anil M.; Norris, David Gordon

    2015-01-01

    Background and Purpose White matter hyperintensities (WMH) are associated with clinically heterogeneous symptoms that cannot be explained by these lesions alone. It is hypothesized that these lesions are associated with distant cortical atrophy and cortical thickness network measures, which can

  13. Cortical source localization of infant cognition.

    Science.gov (United States)

    Reynolds, Greg D; Richards, John E

    2009-01-01

    Neuroimaging techniques such as positron emission topography (PET) and functional magnetic resonance imaging (fMRI) have been utilized with older children and adults to identify cortical sources of perceptual and cognitive processes. However, due to practical and ethical concerns, these techniques cannot be routinely applied to infant participants. An alternative to such neuroimaging techniques appropriate for use with infant participants is high-density electroencephalogram (EEG) recording and cortical source localization techniques. The current article provides an overview of a method developed for such analyses. The method consists of four steps: (1) recording high-density (e.g., 128-channel) EEG. (2) Analysis of individual participant raw segmented data with independent component analysis (ICA). (3) Estimation of equivalent current dipoles (ECDs) that represent cortical sources for the observed ICA component clusters. (4) Calculation of component activations in relation to experimental factors. We discuss an example of research applying this technique to investigate the development of visual attention and recognition memory. We also describe the application of "realistic head modeling" to address some of the current limitations of infant cortical source localization.

  14. A case of cortical deafness and anarthria.

    Science.gov (United States)

    Kaga, Kimitaka; Nakamura, Masako; Takayama, Yoshihiro; Momose, Hiromitsu

    2004-03-01

    Generally, cortical deafness is not complicated by anarthria and cortical anarthria does not affect auditory perception. We report a case of simultaneous progressive cortical deafness and anarthria. At the age of 70 years, the patient, a woman, noticed hearing problems when using the telephone, which worsened rapidly over the next 2 years. She was then referred to our hospital for further examinations of her hearing problems. Auditory tests revealed threshold elevation in the low and middle frequencies on pure-tone audiometry, a maximum speech discrimination of 25% and normal otoacoustic emissions and auditory brainstem, middle- and long-latency responses. An articulation test revealed abnormal pronunciation. Because of these problems only written and not verbal communication was possible; her ability to read and write was unimpaired. She showed no other neurological problems. Brain MRI demonstrated atrophic changes of the auditory cortex and Wernicke's language center and PET suggested low uptake of (18F) 2-fluoro-2-deoxy-d-glucose around the Sylvian fissures in both hemispheres. Neurologically, the patient was suspected of having progressive aphasia or frontotemporal dementia. Her cortical deafness and anarthria are believed to be early signs of this entity.

  15. Cortical motor contributions to language understanding

    NARCIS (Netherlands)

    Willems, R.M.; Hagoort, Peter

    2013-01-01

    Here we review evidence from cognitive neuroscience for a tight relation between language and action in the brain. We focus on two types of relation between language and action. First, we investigate whether the perception of speech and speech sounds leads to activation of parts of the cortical

  16. Cortical correlates of acquired deafness to dissonance.

    Science.gov (United States)

    Brattico, Elvira; Tervaniemi, Mari; Valimaki, Vesa; Van Zuijen, Titia; Peretz, Isabelle

    2003-11-01

    Patient I.R., who had bilateral lesions in the auditory cortex but intact hearing, did not distinguish dissonant from consonant musical excerpts in behavioral testing. We additionally found that the electrical brain responses did not differentiate musical intervals in terms of their dissonance/consonance, consistent with the idea that this phenomenon depends on the integrity of cortical functions.

  17. Cortical mechanisms of mirror therapy after stroke.

    Science.gov (United States)

    Rossiter, Holly E; Borrelli, Mimi R; Borchert, Robin J; Bradbury, David; Ward, Nick S

    2015-06-01

    Mirror therapy is a new form of stroke rehabilitation that uses the mirror reflection of the unaffected hand in place of the affected hand to augment movement training. The mechanism of mirror therapy is not known but is thought to involve changes in cerebral organization. We used magnetoencephalography (MEG) to measure changes in cortical activity during mirror training after stroke. In particular, we examined movement-related changes in the power of cortical oscillations in the beta (15-30 Hz) frequency range, known to be involved in movement. Ten stroke patients with upper limb paresis and 13 healthy controls were recorded using MEG while performing bimanual hand movements in 2 different conditions. In one, subjects looked directly at their affected hand (or dominant hand in controls), and in the other, they looked at a mirror reflection of their unaffected hand in place of their affected hand. The movement-related beta desynchronization was calculated in both primary motor cortices. Movement-related beta desynchronization was symmetrical during bilateral movement and unaltered by the mirror condition in controls. In the patients, movement-related beta desynchronization was generally smaller than in controls, but greater in contralesional compared to ipsilesional motor cortex. This initial asymmetry in movement-related beta desynchronization between hemispheres was made more symmetrical by the presence of the mirror. Mirror therapy could potentially aid stroke rehabilitation by normalizing an asymmetrical pattern of movement-related beta desynchronization in primary motor cortices during bilateral movement. © The Author(s) 2014.

  18. Prenatal Alcohol Exposure and Cortical Angiogenesis

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-02-01

    Full Text Available Researchers at Normandy University, and Rouen and Brest Universities, France studied the effects of prenatal alcohol exposure on the cortical microvascular and the action of alcohol, glutamate, and vascular endothelial growth factor A (VEGF on activity, plasticity, and survival of microvessels in mice.

  19. Central cortical cleanup and zonular deficiency

    Science.gov (United States)

    Mansour, Ahmad M; Antonios, Rafic S; Ahmed, Iqbal Ike K

    2016-01-01

    Background Complete removal of the cortex has been advocated to prevent posterior capsular opacification but carries the risk of zonular dehiscence, hence there is a need for a safe maximal cortical cleanup technique in eyes with severe diffuse zonulopathy in subjects above age 90. Methods We used bimanual central cortical cleaning by elevating central fibers and aspirating them toward the periphery. Peripheral cortical fibers were removed passively only when they became loose due to copious irrigation. A one-piece foldable implant was inserted without a capsular tension ring. Postoperative corticosteroid drops were used. Results This technique was safely performed in a dozen eyes with severe pseudo-exfoliation or brunescent cataract with weak zonules. Posterior capsular rupture, iritis, vitreous loss, and lens subluxation were not observed. Moderate capsular phimosis occurred but with maintained central vision. Conclusion The dogma of “complete cortical cleanup” in severe zonulopathy needs to be revisited in favor of a clear visual axis with maximal preservation of the damaged zonules. This technique is ideal in patients above age 90 where posterior capsular opacification and late dislocation of intraocular lens–capsule bag complex are unlikely to occur until several years postoperatively. PMID:27784979

  20. Central cortical cleanup and zonular deficiency

    Directory of Open Access Journals (Sweden)

    Mansour AM

    2016-10-01

    Full Text Available Ahmad M Mansour,1,2 Rafic S Antonios,1 Iqbal Ike K Ahmed3 1Department of Ophthalmology, American University of Beirut, Beirut, Lebanon; 2Department of Ophthalmology, Rafic Hariri University Hospital, Beirut, Lebanon; 3Department of Ophthalmology, University of Toronto, Toronto, ON, Canada Background: Complete removal of the cortex has been advocated to prevent posterior capsular opacification but carries the risk of zonular dehiscence, hence there is a need for a safe maximal cortical cleanup technique in eyes with severe diffuse zonulopathy in subjects above age 90. Methods: We used bimanual central cortical cleaning by elevating central fibers and aspirating them toward the periphery. Peripheral cortical fibers were removed passively only when they became loose due to copious irrigation. A one-piece foldable implant was inserted without a capsular tension ring. Postoperative corticosteroid drops were used. Results: This technique was safely performed in a dozen eyes with severe pseudo-exfoliation or brunescent cataract with weak zonules. Posterior capsular rupture, iritis, vitreous loss, and lens subluxation were not observed. Moderate capsular phimosis occurred but with maintained central vision. Conclusion: The dogma of “complete cortical cleanup” in severe zonulopathy needs to be revisited in favor of a clear visual axis with maximal preservation of the damaged zonules. This technique is ideal in patients above age 90 where posterior capsular opacification and late dislocation of intraocular lens–capsule bag complex are unlikely to occur until several years postoperatively. Keywords: brunescent cataract, cortex aspiration, phacoemulsification, pseudo-exfoliation, weak zonules