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1.
Cell Rep Med ; 5(6): 101566, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38759649

RESUMO

Levodopa-induced dyskinesia (LID) is an intractable motor complication arising in Parkinson's disease with the progression of disease and chronic treatment of levodopa. However, the specific cell assemblies mediating dyskinesia have not been fully elucidated. Here, we utilize the activity-dependent tool to identify three brain regions (globus pallidus external segment [GPe], parafascicular thalamic nucleus, and subthalamic nucleus) that specifically contain dyskinesia-activated ensembles. An intensity-dependent hyperactivity in the dyskinesia-activated subpopulation in GPe (GPeTRAPed in LID) is observed during dyskinesia. Optogenetic inhibition of GPeTRAPed in LID significantly ameliorates LID, whereas reactivation of GPeTRAPed in LID evokes dyskinetic behavior in the levodopa-off state. Simultaneous chemogenetic reactivation of GPeTRAPed in LID and another previously reported ensemble in striatum fully reproduces the dyskinesia induced by high-dose levodopa. Finally, we characterize GPeTRAPed in LID as a subset of prototypic neurons in GPe. These findings provide theoretical foundations for precision medication and modulation of LID in the future.


Assuntos
Discinesia Induzida por Medicamentos , Globo Pálido , Levodopa , Levodopa/efeitos adversos , Globo Pálido/efeitos dos fármacos , Globo Pálido/fisiopatologia , Discinesia Induzida por Medicamentos/fisiopatologia , Discinesia Induzida por Medicamentos/patologia , Animais , Neurônios/efeitos dos fármacos , Masculino , Optogenética , Camundongos , Doença de Parkinson/tratamento farmacológico , Humanos , Núcleo Subtalâmico/efeitos dos fármacos , Núcleo Subtalâmico/fisiopatologia
2.
Neurosci Bull ; 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38801564

RESUMO

The orbitofrontal cortex (ORB), a region crucial for stimulus-reward association, decision-making, and flexible behaviors, extensively connects with other brain areas. However, brain-wide inputs to projection-defined ORB neurons and the distribution of inhibitory neurons postsynaptic to neurons in specific ORB subregions remain poorly characterized. Here we mapped the inputs of five types of projection-specific ORB neurons and ORB outputs to two types of inhibitory neurons. We found that different projection-defined ORB neurons received inputs from similar cortical and thalamic regions, albeit with quantitative variations, particularly in somatomotor areas and medial groups of the dorsal thalamus. By counting parvalbumin (PV) or somatostatin (SST) interneurons innervated by neurons in specific ORB subregions, we found a higher fraction of PV neurons in sensory cortices and a higher fraction of SST neurons in subcortical regions targeted by medial ORB neurons. These results provide insights into understanding and investigating the function of specific ORB neurons.

3.
Science ; 383(6682): eadj9198, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38300992

RESUMO

Mapping single-neuron projections is essential for understanding brain-wide connectivity and diverse functions of the hippocampus (HIP). Here, we reconstructed 10,100 single-neuron projectomes of mouse HIP and classified 43 projectome subtypes with distinct projection patterns. The number of projection targets and axon-tip distribution depended on the soma location along HIP longitudinal and transverse axes. Many projectome subtypes were enriched in specific HIP subdomains defined by spatial transcriptomic profiles. Furthermore, we delineated comprehensive wiring diagrams for HIP neurons projecting exclusively within the HIP formation (HPF) and for those projecting to both intra- and extra-HPF targets. Bihemispheric projecting neurons generally projected to one pair of homologous targets with ipsilateral preference. These organization principles of single-neuron projectomes provide a structural basis for understanding the function of HIP neurons.


Assuntos
Axônios , Mapeamento Encefálico , Hipocampo , Neurônios , Animais , Camundongos , Axônios/fisiologia , Axônios/ultraestrutura , Hipocampo/ultraestrutura , Neurônios/classificação , Neurônios/ultraestrutura , Análise de Célula Única/métodos , Rede Nervosa , Masculino , Camundongos Endogâmicos C57BL
4.
Sci Transl Med ; 15(713): eabo6889, 2023 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-37703352

RESUMO

Tau pathogenesis is a hallmark of many neurodegenerative diseases, including Alzheimer's disease (AD). Although the events leading to initial tau misfolding and subsequent tau spreading in patient brains are largely unknown, traumatic brain injury (TBI) may be a risk factor for tau-mediated neurodegeneration. Using a repetitive TBI (rTBI) paradigm, we report that rTBI induced somatic accumulation of phosphorylated and misfolded tau, as well as neurodegeneration across multiple brain areas in 7-month-old tau transgenic PS19 mice but not wild-type (WT) mice. rTBI accelerated somatic tau pathology in younger PS19 mice and WT mice only after inoculation with tau preformed fibrils and AD brain-derived pathological tau (AD-tau), respectively, suggesting that tau seeds are needed for rTBI-induced somatic tau pathology. rTBI further disrupted axonal microtubules and induced punctate tau and TAR DNA binding protein 43 (TDP-43) pathology in the optic tracts of WT mice. These changes in the optic tract were associated with a decline of visual function. Treatment with a brain-penetrant microtubule-stabilizing molecule reduced rTBI-induced tau, TDP-43 pathogenesis, and neurodegeneration in the optic tract as well as visual dysfunction. Treatment with the microtubule stabilizer also alleviated rTBI-induced tau pathology in the cortices of AD-tau-inoculated WT mice. These results indicate that rTBI facilitates abnormal microtubule organization, pathological tau formation, and neurodegeneration and suggest microtubule stabilization as a potential therapeutic avenue for TBI-induced neurodegeneration.


Assuntos
Doença de Alzheimer , Lesões Encefálicas Traumáticas , Animais , Camundongos , Microtúbulos , Proteínas de Ligação a DNA , Encéfalo , Modelos Animais de Doenças , Excipientes , Camundongos Transgênicos
5.
Neurosci Bull ; 39(10): 1544-1560, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37253985

RESUMO

The secondary motor cortex (M2) encodes choice-related information and plays an important role in cue-guided actions. M2 neurons innervate the dorsal striatum (DS), which also contributes to decision-making behavior, yet how M2 modulates signals in the DS to influence perceptual decision-making is unclear. Using mice performing a visual Go/No-Go task, we showed that inactivating M2 projections to the DS impaired performance by increasing the false alarm (FA) rate to the reward-irrelevant No-Go stimulus. The choice signal of M2 neurons correlated with behavioral performance, and the inactivation of M2 neurons projecting to the DS reduced the choice signal in the DS. By measuring and manipulating the responses of direct or indirect pathway striatal neurons defined by M2 inputs, we found that the indirect pathway neurons exhibited a shorter response latency to the No-Go stimulus, and inactivating their early responses increased the FA rate. These results demonstrate that the M2-to-DS pathway is crucial for suppressing inappropriate responses in perceptual decision behavior.


Assuntos
Córtex Motor , Camundongos , Animais , Corpo Estriado/fisiologia , Neostriado , Neurônios/fisiologia , Tempo de Reação
6.
Neurosci Bull ; 39(4): 559-575, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36209314

RESUMO

Interval timing is involved in a variety of cognitive behaviors such as associative learning and decision-making. While it has been shown that time estimation is adaptive to the temporal context, it remains unclear how interval timing behavior is influenced by recent trial history. Here we found that, in mice trained to perform a licking-based interval timing task, a decrease of inter-reinforcement interval in the previous trial rapidly shifted the time of anticipatory licking earlier. Optogenetic inactivation of the anterior lateral motor cortex (ALM), but not the medial prefrontal cortex, for a short time before reward delivery caused a decrease in the peak time of anticipatory licking in the next trial. Electrophysiological recordings from the ALM showed that the response profiles preceded by short and long inter-reinforcement intervals exhibited task-engagement-dependent temporal scaling. Thus, interval timing is adaptive to recent experience of the temporal interval, and ALM activity during time estimation reflects recent experience of interval.


Assuntos
Reforço Psicológico , Recompensa , Fatores de Tempo , Animais , Camundongos , Cognição , Aprendizagem , Tomada de Decisões
7.
Nat Neurosci ; 25(4): 515-529, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35361973

RESUMO

Prefrontal cortex (PFC) is the cognitive center that integrates and regulates global brain activity. However, the whole-brain organization of PFC axon projections remains poorly understood. Using single-neuron reconstruction of 6,357 mouse PFC projection neurons, we identified 64 projectome-defined subtypes. Each of four previously known major cortico-cortical subnetworks was targeted by a distinct group of PFC subtypes defined by their first-order axon collaterals. Further analysis unraveled topographic rules of soma distribution within PFC, first-order collateral branch point-dependent target selection and terminal arbor distribution-dependent target subdivision. Furthermore, we obtained a high-precision hierarchical map within PFC and three distinct functionally related PFC modules, each enriched with internal recurrent connectivity. Finally, we showed that each transcriptome subtype corresponds to multiple projectome subtypes found in different PFC subregions. Thus, whole-brain single-neuron projectome analysis reveals organization principles of axon projections within and outside PFC and provides the essential basis for elucidating neuronal connectivity underlying diverse PFC functions.


Assuntos
Neurônios , Córtex Pré-Frontal , Animais , Axônios , Encéfalo , Interneurônios , Camundongos , Neurônios/fisiologia , Córtex Pré-Frontal/fisiologia
8.
Cell Rep ; 37(3): 109847, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34686331

RESUMO

Drinking behavior in rodents is characterized by stereotyped, rhythmic licking movement, which is regulated by the basal ganglia. It is unclear how direct and indirect pathways control the lick bout and individual spout contact. We find that inactivating D1 and D2 receptor-expressing medium spiny neurons (MSNs) in the ventrolateral striatum (VLS) oppositely alters the number of licks in a bout. D1- and D2-MSNs exhibit different patterns of lick-sequence-related activity and different phases of oscillation time-locked to the lick cycle. On the timescale of a lick cycle, transient inactivation of D1-MSNs during tongue protrusion reduces spout contact probability, whereas transiently inactivating D2-MSNs has no effect. On the timescale of a lick bout, inactivation of D1-MSNs (D2-MSNs) causes rate increase (decrease) in a subset of basal ganglia output neurons that decrease firing during licking. Our results reveal the distinct roles of D1- and D2-MSNs in regulating licking at both coarse and fine timescales.


Assuntos
Comportamento Animal , Neurônios Dopaminérgicos/fisiologia , Comportamento de Ingestão de Líquido , Vias Neurais/fisiologia , Substância Negra/fisiologia , Estriado Ventral/fisiologia , Potenciais de Ação , Animais , Neurônios Dopaminérgicos/metabolismo , Técnicas In Vitro , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Movimento , Inibição Neural , Vias Neurais/metabolismo , Optogenética , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Comportamento Estereotipado , Substância Negra/metabolismo , Fatores de Tempo , Língua/inervação , Estriado Ventral/metabolismo
9.
Nat Commun ; 11(1): 2784, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493971

RESUMO

The orbitofrontal cortex (OFC) encodes expected outcomes and plays a critical role in flexible, outcome-guided behavior. The OFC projects to primary visual cortex (V1), yet the function of this top-down projection is unclear. We find that optogenetic activation of OFC projection to V1 reduces the amplitude of V1 visual responses via the recruitment of local somatostatin-expressing (SST) interneurons. Using mice performing a Go/No-Go visual task, we show that the OFC projection to V1 mediates the outcome-expectancy modulation of V1 responses to the reward-irrelevant No-Go stimulus. Furthermore, V1-projecting OFC neurons reduce firing during expectation of reward. In addition, chronic optogenetic inactivation of OFC projection to V1 impairs, whereas chronic activation of SST interneurons in V1 improves the learning of Go/No-Go visual task, without affecting the immediate performance. Thus, OFC top-down projection to V1 is crucial to drive visual associative learning by modulating the response gain of V1 neurons to non-relevant stimulus.


Assuntos
Aprendizagem/fisiologia , Córtex Pré-Frontal/fisiologia , Córtex Visual/fisiologia , Animais , Axônios/fisiologia , Axônios/efeitos da radiação , Comportamento Animal , Potenciais Pós-Sinápticos Excitadores/efeitos da radiação , Potenciais Pós-Sinápticos Inibidores/efeitos da radiação , Lasers , Luz , Camundongos Endogâmicos C57BL , Estimulação Luminosa , Córtex Pré-Frontal/efeitos da radiação , Recompensa , Análise e Desempenho de Tarefas , Córtex Visual/efeitos da radiação
10.
Elife ; 92020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32579113

RESUMO

Adaptive action selection during stimulus categorization is an important feature of flexible behavior. To examine neural mechanism underlying this process, we trained mice to categorize the spatial frequencies of visual stimuli according to a boundary that changed between blocks of trials in a session. Using a model with a dynamic decision criterion, we found that sensory history was important for adaptive action selection after the switch of boundary. Bilateral inactivation of the secondary motor cortex (M2) impaired adaptive action selection by reducing the behavioral influence of sensory history. Electrophysiological recordings showed that M2 neurons carried more information about upcoming choice and previous sensory stimuli when sensorimotor association was being remapped than when it was stable. Thus, M2 causally contributes to flexible action selection during stimulus categorization, with the representations of upcoming choice and sensory history regulated by the demand to remap stimulus-action association.


Assuntos
Córtex Motor/fisiologia , Percepção Visual/fisiologia , Animais , Comportamento Animal , Tomada de Decisões , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia
11.
Cell ; 181(3): 590-603.e16, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32272060

RESUMO

Conversion of glial cells into functional neurons represents a potential therapeutic approach for replenishing neuronal loss associated with neurodegenerative diseases and brain injury. Previous attempts in this area using expression of transcription factors were hindered by the low conversion efficiency and failure of generating desired neuronal types in vivo. Here, we report that downregulation of a single RNA-binding protein, polypyrimidine tract-binding protein 1 (Ptbp1), using in vivo viral delivery of a recently developed RNA-targeting CRISPR system CasRx, resulted in the conversion of Müller glia into retinal ganglion cells (RGCs) with a high efficiency, leading to the alleviation of disease symptoms associated with RGC loss. Furthermore, this approach also induced neurons with dopaminergic features in the striatum and alleviated motor defects in a Parkinson's disease mouse model. Thus, glia-to-neuron conversion by CasRx-mediated Ptbp1 knockdown represents a promising in vivo genetic approach for treating a variety of disorders due to neuronal loss.


Assuntos
Neurogênese/fisiologia , Neuroglia/metabolismo , Células Ganglionares da Retina/metabolismo , Animais , Sistemas CRISPR-Cas/fisiologia , Diferenciação Celular/fisiologia , Células Cultivadas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Modelos Animais de Doenças , Dopamina/metabolismo , Regulação da Expressão Gênica/genética , Ribonucleoproteínas Nucleares Heterogêneas/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Doenças do Sistema Nervoso/metabolismo , Neurônios/metabolismo , Doença de Parkinson/metabolismo , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , Proteína de Ligação a Regiões Ricas em Polipirimidinas/metabolismo , Células Ganglionares da Retina/fisiologia
12.
Neuroscience ; 409: 1-15, 2019 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-30986438

RESUMO

Perceptual decisions, especially for difficult stimuli, can be influenced by choices and outcomes in previous trials. However, it is not well understood how stimulus strength modulates the temporal characteristics as well as the magnitude of trial history influence. We addressed this question using a contrast detection task in freely moving mice. We found that, at lower as compared to higher stimulus contrast, the current choice of the mice was more influenced by choices and outcomes in the past trials and the influence emerged from a longer history. To examine the neural basis of stimulus strength-dependent history influence, we recorded from the secondary motor cortex (M2), a prefrontal region that plays an important role in cue-guided actions and memory-guided behaviors. We found that more M2 neurons conveyed information about choices on the past two trials at lower than at higher contrast. Furthermore, history-trial activity in M2 was important for decoding upcoming choice at low contrast. Thus, trial history influence of perceptual choice is adaptive to the strength of sensory evidence, which may be important for action selection in a dynamic environment.


Assuntos
Potenciais de Ação/fisiologia , Comportamento de Escolha/fisiologia , Córtex Motor/fisiologia , Neurônios/fisiologia , Estimulação Acústica , Animais , Sinais (Psicologia) , Masculino , Camundongos , Estimulação Luminosa
13.
Neuroscience ; 379: 359-374, 2018 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-29608945

RESUMO

In the primary visual cortex (V1), neuronal responses to stimuli within the receptive field (RF) are modulated by stimuli in the RF surround. A common effect of surround modulation is surround suppression, which is dependent on the feature difference between stimuli within and surround the RF and is suggested to be involved in the perceptual phenomenon of figure-ground segregation. In this study, we examined the relationship between feature-specific surround suppression of V1 neurons and figure detection behavior based on figure-ground feature difference. We trained freely moving mice to perform a figure detection task using figure and ground gratings that differed in spatial phase. The performance of figure detection increased with the figure-ground phase difference, and was modulated by stimulus contrast. Electrophysiological recordings from V1 in head-fixed mice showed that the increase in phase difference between stimuli within and surround the RF caused a reduction in surround suppression, which was associated with an increase in V1 neural discrimination between stimuli with and without RF-surround phase difference. Consistent with the behavioral performance, the sensitivity of V1 neurons to RF-surround phase difference could be influenced by stimulus contrast. Furthermore, inhibiting V1 by optogenetically activating either parvalbumin (PV)- or somatostatin (SOM)-expressing inhibitory neurons both decreased the behavioral performance of figure detection. Thus, the phase-specific surround suppression in V1 represents a neural correlate of figure detection behavior based on figure-ground phase discontinuity.


Assuntos
Neurônios/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Animais , Feminino , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Inibição Neural/fisiologia , Optogenética , Parvalbuminas/metabolismo , Somatostatina/metabolismo
14.
Sci Rep ; 7(1): 6468, 2017 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-28743991

RESUMO

As an epigenetic modulator of gene expression, Methyl-CpG binding protein 2 (MeCP2) is essential for normal neurological function. Dysfunction of MeCP2 is associated with a variety of neurological disorders. MECP2 gene duplication in human causes neuropsychiatric symptoms such as mental retardation and autism. MeCP2 overexpression in mice results in neurobehavioural disorders, dendritic abnormalities, and synaptic defects. However, how gain of MeCP2 function influences cortical processing of sensory information remains unclear. In this study, we examined visual processing in a mouse model of MECP2 duplication syndrome (MECP2 Tg1 mouse) at 8 and 14 weeks, which were before and after the onset of behavioural symptoms, respectively. In vivo extracellular recordings from primary visual cortex (V1) showed that neurons in Tg1 mice at both adult ages preferred higher spatial frequencies (SFs) than those in wild-type (WT) littermate controls, and the semi-saturation contrasts of neurons were lower in Tg1 mice at 8 weeks but not at 14 weeks. Behavioural experiments showed that the performance for visual detection at high SFs and low contrasts was higher in MECP2 Tg1 mice. Thus, MeCP2 gain-of-function in mice leads to higher visual acuity and contrast sensitivity, both at the levels of cortical response and behavioural performance.


Assuntos
Deficiência Intelectual Ligada ao Cromossomo X/fisiopatologia , Córtex Visual/fisiopatologia , Fatores Etários , Animais , Sensibilidades de Contraste/genética , Modelos Animais de Doenças , Eletrofisiologia , Feminino , Regulação da Expressão Gênica , Masculino , Deficiência Intelectual Ligada ao Cromossomo X/genética , Proteína 2 de Ligação a Metil-CpG/genética , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/patologia , Neurônios/fisiologia , Estimulação Luminosa , Razão Sinal-Ruído , Córtex Visual/citologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia
15.
Sci Rep ; 6: 38917, 2016 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-27941851

RESUMO

Unconscious processing of subliminal visual information, as illustrated by the above-chance accuracy in discriminating invisible visual stimuli, is evident in both blindsight patients and healthy human observers. However, the dependence of such unconscious processing on stimulus properties remains unclear. Here we studied the impact of stimulus luminance and stimulus complexity on the extent of unconscious processing. A testing stimulus presented to one eye was rendered invisible by a masking stimulus presented to the other eye, and healthy human participants made a forced-choice discrimination of the stimulus identity followed by a report of the perceptual awareness. Without awareness of the stimulus existence, participants could nevertheless reach above-chance accuracy in discriminating the stimulus identity. Importantly, the discrimination accuracy for invisible stimuli increased with the stimulus luminance and decreased with the stimulus complexity. These findings suggested that the input signal strength and the input signal complexity can affect the extent of unconscious processing without altering the subjective awareness.


Assuntos
Conscientização , Discriminação Psicológica , Inconsciente Psicológico , Percepção Visual , Adulto , Comportamento de Escolha , Feminino , Humanos , Luminescência , Masculino , Mascaramento Perceptivo , Estimulação Luminosa , Adulto Jovem
16.
Sci Rep ; 5: 15830, 2015 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-26510881

RESUMO

As an important animal model to study the relationship between behaviour and neural activity, the mouse is able to perform a variety of visual tasks, such as orientation discrimination and contrast detection. However, it is not clear how stimulus contrast influences the performance of orientation discrimination in mice. In this study, we used two task designs, two-alternative forced choice (2AFC) and go/no-go, to examine the performance of mice to discriminate two orthogonal orientations at different contrasts. We found that the performance tended to increase with contrast, and the performance at high contrast was better when the stimulus set contained a single contrast than multiple contrasts. Physiological experiments in V1 showed that neural discriminability of two orthogonal orientations increased with contrast. Furthermore, orientation discriminability of V1 neurons at high contrast was higher in the single than in the multiple contrast condition, largely due to smaller response variance in the single contrast condition. Thus, the performance of mice to discriminate orientations at high contrast is adapted to the contrast range in the stimuli, partly attributed to the contrast-range dependent capacity of V1 neurons to discriminate orientations.


Assuntos
Comportamento Animal/fisiologia , Sensibilidades de Contraste/fisiologia , Orientação/fisiologia , Animais , Masculino , Camundongos
17.
Nat Commun ; 6: 6802, 2015 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-25869033

RESUMO

The responses of visual cortical neurons to natural stimuli are both reliable and sparse. These properties require inhibition, yet the contribution of specific types of inhibitory neurons is not well understood. Here we demonstrate that optogenetic suppression of parvalbumin (PV)- but not somatostatin (SOM)-expressing interneurons reduces response reliability in the primary visual cortex of anaesthetized and awake mice. PV suppression leads to increases in the low firing rates and decreases in the high firing rates of cortical neurons, resulting in an overall reduction of the signal-to-noise ratio (SNR). In contrast, SOM suppression generally increases the overall firing rate for most neurons, without affecting the SNR. Further analysis reveals that PV, but not SOM, suppression impairs neural discrimination of natural stimuli. Together, these results reveal a critical role for PV interneurons in the formation of reliable visual cortical representations of natural stimuli.


Assuntos
Potenciais Evocados Visuais/genética , Interneurônios/metabolismo , Inibição Neural/genética , Parvalbuminas/genética , Somatostatina/genética , Córtex Visual/metabolismo , Anestesia , Animais , Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Interneurônios/citologia , Camundongos , Camundongos Transgênicos , Optogenética , Parvalbuminas/metabolismo , Estimulação Luminosa , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Reprodutibilidade dos Testes , Rodopsinas Microbianas/genética , Rodopsinas Microbianas/metabolismo , Razão Sinal-Ruído , Somatostatina/metabolismo , Transmissão Sináptica/genética , Córtex Visual/citologia , Vigília/fisiologia
18.
Eur J Neurosci ; 39(12): 2060-70, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24931049

RESUMO

Both theoretical and experimental studies suggest that response properties in the visual system are shaped by signals in the natural environment. Recent studies showed that, in the primary visual cortex (V1), neurons preferring light decrements (OFF stimuli) outnumber those preferring light increments (ON stimuli). However, it is not clear whether the OFF-dominance in V1 neurons is related to the contrast statistics in natural images. By analysing the distribution of negative and positive contrasts in natural images at several spatial scales, we showed that optimal coding of the natural contrast signals would lead to a contrast-dependent OFF-dominant response, with a stronger degree of OFF-dominance at a higher contrast. Using bright and dark stimuli at various contrast levels to measure the receptive fields of neurons in cat V1, we found an increasing degree of OFF-dominance of the neuronal population as the contrast was increased. By modeling receptive fields exhibiting OFF- and ON-dominance, we found that contrast-dependent OFF-dominance facilitated the discrimination of stimuli with natural contrast distribution. Thus, by matching contrast-dependent OFF-dominance to the statistics of contrast distribution in natural images, V1 neurons may better discriminate contrast information in natural scenes.


Assuntos
Sensibilidades de Contraste/fisiologia , Discriminação Psicológica/fisiologia , Neurônios/fisiologia , Córtex Visual/fisiologia , Potenciais de Ação , Animais , Gatos , Eletrodos Implantados , Feminino , Masculino , Modelos Neurológicos , Dinâmica não Linear , Estimulação Luminosa/métodos
19.
Nat Neurosci ; 17(3): 391-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24464043

RESUMO

Sensory experience is critical to development and plasticity of neural circuits. Here we report a new form of plasticity in neonatal mice, where early sensory experience cross-modally regulates development of all sensory cortices via oxytocin signaling. Unimodal sensory deprivation from birth through whisker deprivation or dark rearing reduced excitatory synaptic transmission in the correspondent sensory cortex and cross-modally in other sensory cortices. Sensory experience regulated synthesis and secretion of the neuropeptide oxytocin as well as its level in the cortex. Both in vivo oxytocin injection and increased sensory experience elevated excitatory synaptic transmission in multiple sensory cortices and significantly rescued the effects of sensory deprivation. Together, these results identify a new function for oxytocin in promoting cross-modal, experience-dependent cortical development. This link between sensory experience and oxytocin is particularly relevant to autism, where hypersensitivity or hyposensitivity to sensory inputs is prevalent and oxytocin is a hotly debated potential therapy.


Assuntos
Plasticidade Neuronal/fisiologia , Ocitocina/fisiologia , Córtex Somatossensorial/fisiologia , Animais , Animais Recém-Nascidos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ocitocina/administração & dosagem , Ocitocina/farmacologia , Privação Sensorial/fisiologia , Transdução de Sinais/fisiologia , Córtex Somatossensorial/crescimento & desenvolvimento , Córtex Somatossensorial/metabolismo , Transmissão Sináptica/fisiologia
20.
Proc Natl Acad Sci U S A ; 111(1): 515-20, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24347634

RESUMO

Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals.


Assuntos
Encéfalo/fisiologia , Tempo de Reação , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Animais , Eletrodos , Eletroencefalografia , Eletrofisiologia , Corpos Geniculados/fisiologia , Masculino , Potenciais da Membrana/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Ratos , Ratos Long-Evans , Sinapses/fisiologia , Fatores de Tempo
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