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"Как мы тогда бухали" (стихи) [Mar. 22nd, 2019|02:39 am]

lj_keburga
Сам-то я не имею ни бумажных,
ни файловых фотоальбомов
повествующих о том как "мы тогда бухали".
"Тогда", это имеется в виду, что в школе,
в институте и в пресловутые 90-е.
Но у моих одноклассников и сокурсников
такого фотоматериала много хранится.

Например у Н.С. есть чёрный пластиковый мешок,
буквально, набитый подобными фото.
В этом безразличном изобилии
прозябает даже одна реально художественная фотка,
где А.П., И.К. и я - пьём водку в Загородном саду
 у сухого фонтана, пьём из классического гранёного стакана
имени Веры Мухиной. На момент фотографирования,
этот стакан держит, радостно улыбающийся, А.П.,
а сумрачный И.К. сосредоточенно распаковывает
плавленный сырок (они продавались завёрнутыми в
фольгу), а я держу прозрачную, опустелую бутылку
и мечтательно гляжу в направлении
Судостроительного завода
поверх их голов.

Водка та была сорта "Пшеничная" и,
насколько я помню, ишимского
производства. Пьём мы на троих, а четвёртым
был А.Ч., который нас и сфотографировал при
помощи фотоаппарата "Зенит".
Пить же водку А.Ч. в тот день не мог,
поскольку должен был ехать с родителями на дачу
уже буквально через полчаса, и он опасался, что будет
репрессирован за "запах в машине". Родители у А.Ч.
были суровыми и бдительными воспитателями
и отслеживали не только
 запах водки, но и даже запах табака.
На этом фото - поздняя осень 1980 года.
Я и И.К. учимся в 10-м классе школы №40,
а художник А.П. - перешёл на 2-й курс
тюменского Училища Искусств.

И к чему я это всё... а, вот -
я думаю, что молодёжь в СССР
так массово и сильно бухала потому,
что мы жили в мире обещанной сказки.
И мы ещё не были тогда уверены в том,
что эта сказка не состоится и потому
постоянно хотели её словно бы приблизить,
чтобы окунуться и ощутить.
Алкоголь хорошо помогал нам в этом.
Нашим молодым и сильным телам
достаточно было даже такой,
относительно небольшой,
дематериализации, чтобы обещанная
сказка проступила, как уже состоявшаяся
явь и стала доступной для органов чувств.

Поэтому можно сказать, что бухая -
 мы приближали наступление коммунизма.
Мы словно бы подтягивали этот коммунизм к себе
из того прекрасного далЁка, где он размещался.
Подтягивали настолько, что даже оказывались внутри него,
внутри его счастливого, немного восторженного мира,
так похожего на лёгкое опьянение.


фото взял здесь
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The GABA-Glutamate supramammillary-dorsal Dentate Gyrus pathway controls theta and gamma oscillations in the DG during paradoxical sleep [Mar. 22nd, 2019|01:00 am]
syn_bx_neuro
Several studies suggest that neurons from the lateral region of the SuM (SuML) innervating the dorsal dentate gyrus (DG) display a dual GABAergic and glutamatergic transmission and are specifically activated during paradoxical (REM) sleep (PS). The objective of the present study is to fully characterize the anatomical, neurochemical and electrophysiological properties of the SuML-DG projection neurons and to determine how they control DG oscillations and neuronal activation during PS and other vigilance states. For this purpose, we combine structural connectivity techniques using neurotropic viral vectors (rabies virus, AAV), neurochemical anatomy (immunohistochemistry, in situ hybridization) and imaging (light, electron and confocal microscopy) with in vitro (patch clamp) and in vivo (LFP, EEG) optogenetic and electrophysiological recordings performed in transgenic VGLUT2-cre mice. At the cellular level, we show that the SuML-DG neurons co-releases GABA and glutamate on dentate granule cells and increase the activity of a subset of DG granule cells. At the network level, we show that the activation of the SuML-DG pathway increases theta power and frequency during PS as well as gamma power during PS and waking in the DG. At the behavioral level, we show that the activation of this pathway does not change animal behavior during PS, induces awakening during slow wave sleep and increases motor and exploratory activity during waking. These results suggest that the SuML-DG pathway is capable of supporting the increase of theta and gamma power in the DG observed during PS and plays an important modulatory role of DG network activity during this state.
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Beta secretase 1-dependent amyloid precursor protein processing promotes excessive vascular sprouting through NOTCH3 signaling [Mar. 22nd, 2019|12:33 am]
syn_bx_neuro
Amyloid beta peptides (A{beta}) proteins play a key role in vascular pathology in Alzheimer's Disease (AD) including impairment of the blood brain barrier and aberrant angiogenesis. Although previous work has demonstrated a pro-angiogenic role of A{beta}, the exact mechanisms by which amyloid precursor protein (APP) processing and endothelial angiogenic signalling cascades interact in AD remain a largely unsolved problem. Here, we report that increased endothelial sprouting in human-APP transgenic mouse (TgCRND8) tissue is dependent on {beta}-secretase (BACE1) processing of APP. Higher levels of A{beta} processing in TgCRND8 tissue coincides with decreased NOTCH3/JAG1 signalling, over-production of endothelial filopodia and increased numbers of vascular pericytes. Using a novel in vitro approach to study sprouting angiogenesis in TgCRND8 organotypic brain slice cultures (OBSCs), we find that BACE1 inhibition normalises excessive endothelial filopodia formation and restores NOTCH3 signalling. These data present the first evidence for the potential of BACE1 inhibition as an effective therapeutic target for aberrant angiogenesis in AD.
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An image-computable model for the stimulus selectivity of gamma oscillations [Mar. 22nd, 2019|12:33 am]
syn_bx_neuro
Gamma oscillations in visual cortex have been hypothesized to play a general role in perception, cognition, and information transfer. However, observations of gamma oscillations have varied widely, with some studies of visual cortex reporting little to no stimulus evoked narrowband gamma oscillations, some reporting gamma oscillations for only some stimuli, and some reporting large oscillations for all or most stimuli tested. To reconcile these findings and gain a better understanding of this signal, we developed a model that predicts gamma responses for arbitrary images and validated this model on data from visual cortex in human patients with implanted surface electrodes (ECoG). The model computes variance across the outputs of spatially pooled orientation channels, and accurately predicts the amplitude of gamma oscillations across 86 images. Gamma responses are large for only a small subset of stimuli tested, and this pattern of responses (both data and model predictions) differs dramatically from fMRI BOLD signals and ECoG broadband (non-oscillatory) field potentials measured for the same images. We suggest that gamma oscillations in visual cortex serve as a biomarker of inhibition or gain control rather than being a fundamental mechanism for communicating visual information.
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Accelerated brain ageing and disability in multiple sclerosis [Mar. 22nd, 2019|12:33 am]
syn_bx_neuro
Background: Brain atrophy occurs in both normal ageing and in multiple sclerosis (MS), but it occurs at a faster rate in MS, where it is the major driver of disability progression. Here, we employed a neuroimaging biomarker of structural brain ageing to explore how MS influences the brain ageing process. Methods: In a longitudinal, multi-centre sample of 3,565 MRI scans in 1,204 MS/clinically isolated syndrome (CIS) patients and 150 healthy controls (HCs) (mean follow-up time: patients 3.41 years, HCs 1.97 years) we measured brain-predicted age using T1-weighted MRI. Brain-predicted age difference (brain-PAD) was calculated as the difference between the brain-predicted age and chronological age. Positive brain-PAD indicates a brain appears older than its chronological age. We compared brain-PAD between MS/CIS patients and HCs, and between disease subtypes. In patients, the relationship between brain-PAD and Expanded Disability Status Scale (EDSS) at study entry and over time was explored. Findings: Adjusted for age, sex, intracranial volume, cohort and scanner effects MS/CIS patients had markedly older-appearing brains than HCs (mean brain-PAD 11.8 years [95% CI 9.1-14.5] versus -0.01 [-3.0-3.0], p<0.0001). All MS subtypes had greater brain-PAD scores than HCs, with the oldest-appearing brains in secondary-progressive MS (mean brain-PAD 18.0 years [15.4-20.5], p<0.05). At baseline, higher brain-PAD was associated with a higher EDSS, longer time since diagnosis and a younger age at diagnosis. Brain-PAD at study entry significantly predicted time-to-EDSS progression (hazard ratio 1.02 [1.01-1.03], p<0.0001): for every 5 years of additional brain-PAD, the risk of progression increased by 14.2%. Interpretation: MS increases brain ageing across all MS subtypes. An older-appearing brain at baseline was associated with more rapid disability progression, suggesting brain-age could be an individualised prognostic biomarker from a single, cross-sectional assessment. Funding: UK MS Society; National Institute for Health Research University College London Hospitals Biomedical Research Centre.
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Modeling mechanisms of tremor reduction for essential tremor using symmetric biphasic DBS [Mar. 22nd, 2019|12:00 am]
syn_bx_neuro
Essential tremor (ET) is the most common movement disorder, in which the primary symptom is a prominent, involuntary 4-10 Hz movement. For severe, medication refractory cases, deep brain stimulation (DBS) targeting the ventral intermediate nucleus of the thalamus (VIM) can be an effective treatment for cessation of tremor and is thought to work in part by disrupting tremor frequency oscillations (TFOs) in VIM. However, DBS is not universally effective and may be further disrupting cerebellar-mediated activity in the VIM. Here, we applied biophysically detailed computational modeling to investigate whether the efficacy of DBS is affected by the mechanism of generation of TFOs or by the pattern of stimulation. We simulated the effects of DBS using standard, asymmetric pulses as well as biphasic, symmetric pulses to understand biophysical mechanisms of how DBS disrupts TFOs generated either extrinsically or intrinsically. The model results suggested that the efficacy of DBS in the VIM is affected by the mechanism of generation of TFOs. Symmetric biphasic DBS reduced TFOs more than standard DBS in both networks, and these effects were stronger in the intrinsic network. For intrinsic tremor frequency activity, symmetric biphasic DBS was more effective at reducing TFOs. Simulated non-tremor signals were also transmitted during symmetric biphasic DBS, suggesting that this type of DBS may help to reduce side effects caused by disruption of the cerebellothalamocortical pathway. Biophysical details in the model provided a mechanistic interpretation of the cellular and network dynamics contributing to these effects that can be empirically tested in future studies.
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Effects of healthy ageing on activation pattern within the brain during movement and motor imagery: an fMRI study. [Mar. 21st, 2019|11:30 pm]
syn_bx_neuro
Introduction: Motor imagery (MI) has potential as an intervention to improve performance in neurological disease affecting the motor system and to modulate brain computer interfaces (BCI). We hypothesized that the shared networks of MI and executed movement (EM) would be affected by age. Understanding these changes is important in application of MI in neurological disorders. Methods: Using tensor-independent component analysis (TICA), we mapped the neural networks involved during MI and EM in 31 healthy volunteers (ages 20-72), who were recruited and screened for their ability to perform imagery. We used an fMRI block-design with MI & rest and EM & rest. Results: TICA defined 37 independent components (ICs). Eight remained after excluding ICs representing artifacts. These ICs accounted for 35% of variance. While all ICs had greater activation in EM than MI. Two ICs increased with greater age for EM only. These ICs contained a bilateral network of brain areas, including primary motor cortex and cerebellum. Conclusion: This study demonstrates the prominence of shared cerebral networks between MI and EM. There are age-dependent changes to EM activation, while MI activation appeared age independent. This strengthens the rationale for using MI to access the motor networks independent of age.
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Impairment but not abolishment of express saccades after unilateral- or bilateral cryogenic FEF inactivation [Mar. 21st, 2019|11:30 pm]
syn_bx_neuro
Express saccades (ESs) are a manifestation of a visual grasp reflex triggered when visual information arrives in the intermediate layers of the superior colliculus (SCi), which in turn orchestrates the lower level brainstem saccade generator to evoke a saccade with a very short latency (~100ms). A prominent theory regarding express saccades generation is that they are facilitated by preparatory signals, presumably from cortical areas, which prime the SCi prior to the arrival of visual information. Here, we test this theory by reversibly inactivating a key cortical input to the SCi, the frontal eye fields (FEF), while monkeys perform an oculomotor task that promotes ES generation. Across three tasks with a different combination of potential target locations and uni- or bilateral FEF inactivation, we found a spared ability for monkeys to generate ESs, despite decreases in ES frequency during FEF inactivation. This result is consistent with the FEF having a facilitatory but not critical role in ES generation, likely because other cortical areas compensate for the loss of preparatory input to the SCi. However, we did find decreases in the accuracy and peak velocity of ESs generated during FEF inactivation, which argues for an influence of the FEF on the saccadic burst generator even during ESs. Overall, our results shed further light on the role of the FEF in the shortest-latency visually-guided eye movements.
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Confidence reports in decision-making with multiple alternatives violate the Bayesian confidence hypothesis [Mar. 21st, 2019|11:30 pm]
syn_bx_neuro
Decision confidence reflects our ability to evaluate the quality of decisions and guides subsequent behaviors. Experiments on confidence reports have almost exclusively focused on two-alternative decision-making. In this realm, the leading theory is that confidence reflects the probability that a decision is correct (the posterior probability of the chosen option). There is, however, another possibility, namely that people are less confident if the best two options are closer to each other in posterior probability, regardless of how probable they are in absolute terms. This possibility has not previously been considered because in two-alternative decisions, it reduces to the leading theory. Here, we test this alternative theory in a three-alternative visual categorization task. We found that confidence reports are best explained by the difference between the posterior probabilities of the best and the next-best options, rather than by the posterior probability of the chosen (best) option alone, or by the overall uncertainty (entropy) of the posterior distribution. Our results upend the leading notion of decision confidence and instead suggest that confidence reflects the observer's subjective probability that they made the best possible decision.
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Superlets: time-frequency super-resolution using wavelet sets [Mar. 21st, 2019|11:30 pm]
syn_bx_neuro
Time-frequency analysis is ubiquitous in many fields of science. Due to the Heisenberg-Gabor uncertainty principle, a single measurement cannot estimate precisely the localization of a finite signal in both time and frequency. Classical spectral estimators, like the short-time Fourier transform (STFT) or the continuous-wavelet transform (CWT) optimize either temporal or frequency resolution, or find a tradeoff that is suboptimal in both dimensions. Following the concept of optical super-resolution, we introduce a new spectral estimation method that enables time-frequency super-resolution. Sets of wavelets with increasing bandwidth are combined geometrically in a superlet to maintain the good temporal resolution of wavelets and gain frequency resolution in the high frequency range. We show that superlets outperform the STFT and CWT on synthetic data and brain signals recorded in humans and rodents. Superlets are able to resolve temporal and frequency details with unprecedented precision, revealing transient oscillation events otherwise hidden in averaged time-frequency analyses.
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Под "Черными парусами": Капитан Флинт [Mar. 21st, 2019|10:45 pm]

lj_qebedo
У полностью придуманного Стивенсоном персонажа нет даже имени - он Дж. Флинт, что породило у подражателей кучу вариантов: Джон, Джозеф, Джошуа и даже Джетроу. Не нарушили традиции и создатели сериала - у них Флинта зовут Джеймс, а настоящая его фамилия МакГроу (скорее всего, навеянная последними словами капитана в перед смертью, которые запомнили его пираты: "Дарби МакГроу, рому!"). Поскольку действие "Острова сокровищ" разворачивается через много лет после смерти Флинта, он присутствует лишь в многочисленных воспоминаниях его бывших подчиненных, которые рисуют почти демоническую фигуру - кровожадный алкоголик, способный в одиночку расправиться с шестерыми здоровыми матросами, беспощадный и пользующийся ужасающей славой (капитан судна, на котором плыл сквайр Трелони, пустился в бегство, едва завидя кончики мачт корабля Флинта Вальрус, он же Морж).


В сериале роль капитана Флинта исполнил Тоби Стивенс

Умер он нехарактерной для джентльмена удачи смертью - в американском порту Саванна от белой горячки. Но перед тем спрятал награбленные сокровища (около четверти миллиона фунтов - огромные деньги по тем временам) на необитаемом острове, карту которого получил на хранение его старший помощник Билли Бонс. К слову, когда Флинт вернулся с острова, где зарыл клад, а заодно и шестерых матросов (не всех - из одного, Аллардайса, сделал "стрелку компаса"), Сильвер и Бонс попытались выведать у него точное место, но получили "жесткий отлуп".

Фамилия у Флинта, кстати, говорящая - по-английски это слово означает кремень, причем в том числе и в "том самом" смысле твердого, несгибаемого человека. Также существует сокращенная форма флинт от флинтлок, означающая кремневый оружейный замок. Прототипов образа Флинта существует столько, сколько человек начинали по этому поводу фантазировать. Французский писатель Пьер Мак-Орлан, в предисловии к переводу "Всеобщей истории..." капитана Чарлза Джонсона (ака Даниэля де Фо) "зуб давал", что другой писатель, англичанин Чарлз Уайтхед, упоминал Флинта в книге "Жизнь и подвиги разбойников, пиратов и грабителей всех наций", но до сих пор никто в сети так и не выложил пруфующую сие цитату.



Популярнее всего теория о Эдварде Черной Бороде Тиче как о прототипе, но доказательства ее адепты проводят почти смехотворные - он-де "был страшный, известный и умер (хоть и в бою) недалеко от Саванны". Единственный их серьезный пруф - один из пиратов в романе, Израэль Хэндс, в реальной истории служил под командой Тича капитаном вспомогательного корабля. Но знаменитая фраза Сильвера о том, что "Черная Борода перед Флинтом - младенец", жестко опровергает эту версию. Еще один кандидат - пират Джеймс Тейлор, начинавший карьеру в команде Эдварда Инглэнда.

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Leptin reduces pathology and increases adult neurogenesis in a transgenic mouse model of Alzheimer\'s disease. [Mar. 21st, 2019|11:01 pm]
syn_bx_neuro
Alzheimer's disease (AD) is the most common dementia worldwide, and is characterized by the presence, in the brain tissue, of extracellular senile plaques formed by amyloid beta (A{beta}) peptide and intracellular neurofibrillary tangles of hyperphosphorylated Tau protein. These changes lead to progressive neuronal degeneration and dysfunction, resulting in severe brain atrophy and cognitive deficits. With the discovery that neurogenesis persists in the adult mammalian brain, including brain regions affected by AD, studies of the use of neural stem cells for treatment of neurodegenerative diseases in order to repair and/or prevent neuronal cell loss have increased. Here we show that leptin increases neurogenesis in the dentate gyrus of adult mice as well as in the subventricular zone both in wild type and AD transgenic mouse model. Chronic administration of leptin to young mice increased neural stem cell proliferation with significant effects on differentiation and survival of newborn cells. Expression of the long form of leptin receptor, LepRb, was detected in the neurogenic niches by reverse transcription-PCR and immunohistochemistry. Moreover, leptin modulated astrogliosis and the formation of senile plaques. Additionally, leptin led to attenuation of A{beta}-induced neurodegeneration and superoxide anion production as revealed by Fluoro-Jade B and dihydroethidium (DHE) staining. Our study contributes to the understanding of the effects of leptin in the brain that may lead to the development of new therapies to treat Alzheimer's disease.
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A Long Timescale Stimulus History Effect in the Primary Visual Cortex [Mar. 21st, 2019|11:01 pm]
syn_bx_neuro
Responses of neurons in the primary visual cortex (V1) are often understood as encoding the current visual stimulus. Yet, some studies indicate that temporal contingency effects exist in the responses of neurons in early sensory areas. We explored if the recent stimulus history would alter the response of V1 layer 2/3 pyramidal cells in head-fixed awake mice during presentation of sequences of complex images. The activity of individual neurons was sparse, such that either one or none of the images in the sequence typically yielded a strong response. We then substituted an image preceding this primary image in order to determine if responses to the primary image were affected. We found that the amplitude of the neuron's response could be significantly altered by substitutions up to five images back from the primary image, even when the substituted image elicited virtually no response by itself. This stimulus history effect was heterogeneous across the population, with some cells showing facilitation and others suppression. For individual cells, the history effect was robust and reproducible across days. Our data show that responses of V1 neurons not only reflect the current stimulus but also encode, through their response amplitude, information about multiple images previously presented as far as 1000 msec in the past. This might enable V1 to retain information about the extended trajectory of past stimuli and perform complex temporal computations that are as of yet not appreciated.
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Relationship between cardiac cycle and the timing of actions during action execution and observation [Mar. 21st, 2019|11:01 pm]
syn_bx_neuro
Previous research suggests that there may be a relationship between the timing of motor events and phases of the cardiac cycle. However, this relationship has thus far only been researched using simple isolated movements such as key-presses in reaction-time tasks and only in a single subject acting alone. Here, we investigated how the cardiac cycle relates to ongoing self-paced movements in both action execution and observation using a novel dyadic paradigm. We recorded electrocardiography (ECG) in 26 subjects who formed 13 dyads containing an action executioner and observer as they performed a self-paced sequence of movements. We demonstrated that heartbeats are timed to movements during both action execution and observation. Specifically, movements were more likely to culminate between heartbeats than simultaneously with the heartbeat. The same pattern was observed for action observation, with the observer's heartbeats occurring off-phase with movement culmination. These findings demonstrate that there is synchronicity between an action executioner's cardiac cycle and the timing of their movements, and that the same relationship is mirrored in an observer. This suggests that interpersonal synchronicity may be caused by the mirroring of a phasic relationship between movement and the heart.
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The role of feature-based attention in visual serial dependence [Mar. 21st, 2019|11:01 pm]
syn_bx_neuro
Perceptual decisions about current sensory input are biased towards input of the recent past - a phenomenon termed serial dependence. Serial dependence may serve to stabilize neural representations in the face of external and internal noise. However, it is unclear under which circumstances previous input attracts subsequent perceptual decisions, and thus, whether serial dependence reflects a broad smoothing or selective stabilization operation. Here, we investigated whether focusing attention on particular features of the previous stimulus modulates serial dependence. We found an attractive bias in orientation estimations when previous and current stimuli had similar orientations, and a repulsive bias when they had dissimilar orientations. The attractive bias was markedly reduced when observers attended to the size, rather than the orientation, of the previous stimulus. Conversely, the repulsive bias for stimuli with large orientation differences was not modulated by feature-based attention. This suggests separate sources of these positive and negative perceptual biases.
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Neuronal network dysfunction in a human model for Kleefstra syndrome mediated by enhanced NMDAR signaling [Mar. 21st, 2019|11:01 pm]
syn_bx_neuro
Epigenetic regulation of gene transcription plays a critical role in neural network development and in the etiology of Intellectual Disability (ID) and Autism Spectrum Disorder (ASD). However, little is known about the mechanisms by which epigenetic dysregulation leads to neural network defects. Kleefstra syndrome (KS), caused by mutation in the histone methyltransferase EHMT1, is a neurodevelopmental disorder with the clinical features of both ID and ASD. To study the impact of decreased EHMT1 function in human cells, we generated excitatory cortical neurons from induced pluripotent stem (iPS) cells derived from KS patients. In addition, we created an isogenic set by genetically editing healthy iPS cells. Characterization of the neurons at the single-cell and neuronal network level revealed consistent discriminative properties that distinguished EHMT1-mutant from wildtype neurons. Mutant neuronal networks exhibited network bursting with a reduced rate, longer duration, and increased temporal irregularity compared to control networks. We show that these changes were mediated by the upregulation of the NMDA receptor (NMDAR) subunit 1 and correlate with reduced deposition of the repressive H3K9me2 mark, the catalytic product of EHMT1, at the GRIN1 promoter. Furthermore, we show that EHMT1 deficiency in mice leads to similar neuronal network impairments and increased NMDAR function. Finally, we could rescue the KS patient-derived neuronal network phenotypes by pharmacological inhibition of NMDARs. Together, our results demonstrate a direct link between EHMT1 deficiency in human neurons and NMDAR hyperfunction, providing the basis for a more targeted therapeutic approach to treating KS.
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Visual area V4 encodes history dependent attentional effort and single-trial perceptual detection [Mar. 21st, 2019|11:01 pm]
syn_bx_neuro
Intense attentional effort improves performance. Neurons in visual area V4 exhibit changes in spike rates that are correlated with effort, selective attention and absolute reward expectation. How neuronal spikes in V4 encode attentional states and perceptual performance with reference to other task relevant motivational and decision signals is poorly understood. We recorded neuronal spikes from monkey visual area V4, and isolated attentional effort from reward expectancy and motor decisions in a visual orientation detection task using a statistical approach based on generalized linear models. We found that V4 spike responses exhibit hysteresis with reward changes. Single trial spiking activity encodes a combination of temporally overlapping sensory and cognitive signals. Neuronal spikes integrate contextual history of attentional effort on a longer time scale, and task related perceptual detection in a shorter timescale within a single trial. Notably, immediate reward expectation and behavioral choice probability are poor predictors of V4 spikes throughout the trial. Further, detection of task relevant perceptual signal is decoded from single trial population spikes with high accuracy. These results provide a detailed representation of perceptual and cognitive signals in V4 that are crucial for performance.
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Intraventricular CXCL12 is neuroprotective and increases neurogenesis in a murine model of stroke [Mar. 21st, 2019|10:30 pm]
syn_bx_neuro
Stroke is the leading cause of physical disability and the second leading cause of death in adults. Chemokines that regulate ischemic microenvironment can influence neurorestorative therapies in stroke patients. CXCL12 was shown to be neuroprotective, but there are some contradictory results in the literature. The objective of this work is to verify whether CXCL12 delivery to the brain could be beneficial or harmful. We decided to evaluate the intraventricular delivery to facilitate its application in clinical practice. Intraventricular CXCL12 was able to produce increased mRNA expression of the receptors CXCR4 and CXCR7 in the cerebral cortex. After the stroke, intraventricular CXCL12 decreased mice ischemic area and improved behavioral response. We found CXCL12 was neuroprotective, increase reactive astrogliosis and improve neurogenesis in the perilesional area.
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Leveraging non-human primate multisensory neurons and circuits in assessing consciousness theory [Mar. 21st, 2019|10:30 pm]
syn_bx_neuro
Both the Global Neuronal Workspace (GNW) and Integrated Information Theory (IIT) posit that highly complex and interconnected networks engender perceptual awareness. GNW specifies that activity recruiting fronto-parietal networks will elicit a subjective experience, while IIT is more concerned with the functional architecture of networks than with activity within it. Here, we argue that according to IIT mathematics, circuits converging on integrative vs. convergent yet non-integrative neurons should support a greater degree of consciousness. We test this hypothesis by analyzing a dataset of neuronal responses collected simultaneously from primary somatosensory cortex (S1) and ventral premotor cortex (vPM) in non-human primates presented with auditory, tactile, and audio-tactile stimuli as they are progressively anesthetized with Propofol. We first describe the multisensory (audio-tactile) characteristics of S1 and vPM neurons (mean and dispersion tendencies, as well as noise-correlations), and functionally label these neurons as convergent or integrative according to their spiking responses. Then, we characterize how these different pools of neurons behave as a function of consciousness. At odds with the IIT mathematics, results suggest that convergent neurons more readily exhibit properties of consciousness (neural complexity and noise correlation) and are more impacted during the loss of consciousness than integrative neurons. Lastly, we provide support for the GNW by showing that neural ignition (i.e., same trial co-activation of S1 and vPM) was more frequent in conscious than unconscious states. Overall, we contrast GNW and IIT within the same single-unit activity dataset, and support the GNW.
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EEG-fMRI reveals rapid representation of personal relevance of faces in social cognition and reward-related brain regions [Mar. 21st, 2019|10:30 pm]
syn_bx_neuro
Faces are a primary source of social information, but little is known about the sequence of neural processes that extract information from highly personally relevant faces, such as those of our loved ones. We applied representational similarity analyses to EEG-fMRI measurement of neural responses to faces of personal relevance to participants - their romantic partner and a friend - compared to a stranger. Faces expressed fear, happiness or no emotion. Shared EEG-fMRI representations started 100ms after stimulus onset not only in visual cortex, but also regions involved in social cognition, value representation and autobiographical memory, including ventromedial prefrontal cortex, temporoparietal junction and posterior cingulate. Representations in fusiform gyrus, amygdala, insular cortex and N. accumbens were evident after 200 ms. Representations related to romantic love emerged after 400ms in subcortical brain regions associated with reward. The results point to the prioritized processing of personal relevance with rapid and extensive cortical representation.
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