RESUMO
Salient sensory stimuli are perceived by the brain, which guides both the timing and outcome of behaviors in a context-dependent manner. Light is such a stimulus, which is used in treating mood disorders often associated with a dysregulated hypothalamic-pituitary-adrenal stress axis. Relationships between the emotional valence of light and the hypothalamus, and how they interact to exert brain-wide impacts remain unclear. Employing larval zebrafish with analogous hypothalamic systems to mammals, we show in free-swimming animals that hypothalamic corticotropin releasing factor (CRFHy) neurons promote dark avoidance, and such role is not shared by other hypothalamic peptidergic neurons. Single-neuron projection analyses uncover processes extended by individual CRFHy neurons to multiple targets including sensorimotor and decision-making areas. In vivo calcium imaging uncovers a complex and heterogeneous response of individual CRFHy neurons to the light or dark stimulus, with a reduced overall sum of CRF neuronal activity in the presence of light. Brain-wide calcium imaging under alternating light/dark stimuli further identifies distinct and distributed photic response neuronal types. CRFHy neuronal ablation increases an overall representation of light in the brain and broadly enhances the functional connectivity associated with an exploratory brain state. These findings delineate brain-wide photic perception, uncover a previously unknown role of CRFHy neurons in regulating the perception and emotional valence of light, and suggest that light therapy may alleviate mood disorders through reducing an overall sum of CRF neuronal activity.
Assuntos
Hormônio Liberador da Corticotropina , Núcleo Hipotalâmico Paraventricular , Animais , Hormônio Liberador da Corticotropina/metabolismo , Núcleo Hipotalâmico Paraventricular/metabolismo , Cálcio , Peixe-Zebra/metabolismo , Hipotálamo/metabolismo , Neurônios/metabolismo , Encéfalo/metabolismo , Percepção , Mamíferos/metabolismoRESUMO
Calcium imaging is a powerful tool for recording from large populations of neurons in vivo. Imaging in rhesus macaque motor cortex can enable the discovery of fundamental principles of motor cortical function and can inform the design of next generation brain-computer interfaces (BCIs). Surface two-photon imaging, however, cannot presently access somatic calcium signals of neurons from all layers of macaque motor cortex due to photon scattering. Here, we demonstrate an implant and imaging system capable of chronic, motion-stabilized two-photon imaging of neuronal calcium signals from macaques engaged in a motor task. By imaging apical dendrites, we achieved optical access to large populations of deep and superficial cortical neurons across dorsal premotor (PMd) and gyral primary motor (M1) cortices. Dendritic signals from individual neurons displayed tuning for different directions of arm movement. Combining several technical advances, we developed an optical BCI (oBCI) driven by these dendritic signalswhich successfully decoded movement direction online. By fusing two-photon functional imaging with CLARITY volumetric imaging, we verified that many imaged dendrites which contributed to oBCI decoding originated from layer 5 output neurons, including a putative Betz cell. This approach establishes new opportunities for studying motor control and designing BCIs via two photon imaging.
Assuntos
Interfaces Cérebro-Computador , Cálcio/metabolismo , Dendritos/fisiologia , Microscopia Intravital/instrumentação , Microscopia Intravital/métodos , Córtex Motor/diagnóstico por imagem , Imagem Multimodal/métodos , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Dendritos/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Implantes Experimentais , Macaca mulatta , Masculino , Modelos Neurológicos , Atividade Motora/fisiologia , Córtex Motor/fisiologia , Neurônios/fisiologia , FótonsRESUMO
Advanced imaging methods now allow cell-type-specific recording of neural activity across the mammalian brain, potentially enabling the exploration of how brain-wide dynamical patterns give rise to complex behavioural states1-12. Dissociation is an altered behavioural state in which the integrity of experience is disrupted, resulting in reproducible cognitive phenomena including the dissociation of stimulus detection from stimulus-related affective responses. Dissociation can occur as a result of trauma, epilepsy or dissociative drug use13,14, but despite its substantial basic and clinical importance, the underlying neurophysiology of this state is unknown. Here we establish such a dissociation-like state in mice, induced by precisely-dosed administration of ketamine or phencyclidine. Large-scale imaging of neural activity revealed that these dissociative agents elicited a 1-3-Hz rhythm in layer 5 neurons of the retrosplenial cortex. Electrophysiological recording with four simultaneously deployed high-density probes revealed rhythmic coupling of the retrosplenial cortex with anatomically connected components of thalamus circuitry, but uncoupling from most other brain regions was observed-including a notable inverse correlation with frontally projecting thalamic nuclei. In testing for causal significance, we found that rhythmic optogenetic activation of retrosplenial cortex layer 5 neurons recapitulated dissociation-like behavioural effects. Local retrosplenial hyperpolarization-activated cyclic-nucleotide-gated potassium channel 1 (HCN1) pacemakers were required for systemic ketamine to induce this rhythm and to elicit dissociation-like behavioural effects. In a patient with focal epilepsy, simultaneous intracranial stereoencephalography recordings from across the brain revealed a similarly localized rhythm in the homologous deep posteromedial cortex that was temporally correlated with pre-seizure self-reported dissociation, and local brief electrical stimulation of this region elicited dissociative experiences. These results identify the molecular, cellular and physiological properties of a conserved deep posteromedial cortical rhythm that underlies states of dissociation.
Assuntos
Ondas Encefálicas/fisiologia , Córtex Cerebral/fisiologia , Transtornos Dissociativos/fisiopatologia , Potenciais de Ação/efeitos dos fármacos , Animais , Comportamento/efeitos dos fármacos , Ondas Encefálicas/efeitos dos fármacos , Córtex Cerebral/citologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/efeitos dos fármacos , Transtornos Dissociativos/diagnóstico por imagem , Eletrofisiologia , Feminino , Humanos , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Ketamina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Optogenética , Autorrelato , Tálamo/citologia , Tálamo/diagnóstico por imagem , Tálamo/efeitos dos fármacos , Tálamo/fisiologiaRESUMO
The hypothalamus is composed of many neuropeptidergic cell populations and directs multiple survival behaviors, including defensive responses to threats. However, the relationship between the peptidergic identity of neurons and their roles in behavior remains unclear. Here, we address this issue by studying the function of multiple neuronal populations in the zebrafish hypothalamus during defensive responses to a variety of homeostatic threats. Cellular registration of large-scale neural activity imaging to multiplexed in situ gene expression revealed that neuronal populations encoding behavioral features encompass multiple overlapping sets of neuropeptidergic cell classes. Manipulations of different cell populations showed that multiple sets of peptidergic neurons play similar behavioral roles in this fast-timescale behavior through glutamate co-release and convergent output to spinal-projecting premotor neurons in the brainstem. Our findings demonstrate that homeostatic threats recruit neurons across multiple hypothalamic cell populations, which cooperatively drive robust defensive behaviors.
Assuntos
Comportamento Animal/fisiologia , Tronco Encefálico/fisiologia , Hipotálamo/fisiologia , Neurônios/fisiologia , Peixe-Zebra/fisiologia , Animais , Cálcio/metabolismo , Vias Neurais/fisiologiaRESUMO
The ability to rapidly arouse from sleep is important for survival. However, increased arousals in patients with sleep apnea and other disorders prevent restful sleep and contribute to cognitive, metabolic, and physiologic dysfunction [1, 2]. Little is currently known about which neural systems mediate these brief arousals, hindering the development of treatments that restore normal sleep. The basal forebrain (BF) receives inputs from many nuclei of the ascending arousal system, including the brainstem parabrachial neurons, which promote arousal in response to elevated blood carbon dioxide levels, as seen in sleep apnea [3]. Optical inhibition of the terminals of parabrachial neurons in the BF impairs cortical arousals to hypercarbia [4], but which BF cell types mediate cortical arousals in response to hypercarbia or other sensory stimuli is unknown. Here, we tested the role of BF parvalbumin (PV) neurons in arousal using optogenetic techniques in mice. Optical stimulation of BF-PV neurons produced rapid transitions to wakefulness from non-rapid eye movement (NREM) sleep but did not affect REM-wakefulness transitions. Unlike previous studies of BF glutamatergic and cholinergic neurons, arousals induced by stimulation of BF-PV neurons were brief and only slightly increased total wake time, reminiscent of clinical findings in sleep apnea [5, 6]. Bilateral optical inhibition of BF-PV neurons increased the latency to arousal produced by exposure to hypercarbia or auditory stimuli. Thus, BF-PV neurons are an important component of the brain circuitry that generates brief arousals from sleep in response to stimuli, which may indicate physiological dysfunction or danger to the organism.
Assuntos
Estimulação Acústica , Nível de Alerta/fisiologia , Carboidratos/administração & dosagem , Neurônios/fisiologia , Ração Animal/análise , Animais , Prosencéfalo Basal/fisiologia , Dieta , Camundongos , Parvalbuminas/metabolismo , Sono/fisiologia , Vigília/fisiologiaRESUMO
Physiological needs produce motivational drives, such as thirst and hunger, that regulate behaviors essential to survival. Hypothalamic neurons sense these needs and must coordinate relevant brainwide neuronal activity to produce the appropriate behavior. We studied dynamics from ~24,000 neurons in 34 brain regions during thirst-motivated choice behavior in 21 mice as they consumed water and became sated. Water-predicting sensory cues elicited activity that rapidly spread throughout the brain of thirsty animals. These dynamics were gated by a brainwide mode of population activity that encoded motivational state. After satiation, focal optogenetic activation of hypothalamic thirst-sensing neurons returned global activity to the pre-satiation state. Thus, motivational states specify initial conditions that determine how a brainwide dynamical system transforms sensory input into behavioral output.
Assuntos
Comportamento de Escolha/fisiologia , Hipotálamo/citologia , Hipotálamo/fisiologia , Vias Neurais/fisiologia , Sede/fisiologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia , Optogenética , Células Receptoras Sensoriais/fisiologia , Análise de Célula ÚnicaRESUMO
Encoding and predicting aversive events are critical functions of circuits that support survival and emotional well-being. Maladaptive circuit changes in emotional valence processing can underlie the pathophysiology of affective disorders. The lateral habenula (LHb) has been linked to aversion and mood regulation through modulation of the dopamine and serotonin systems. We have defined the identity and function of glutamatergic (Vglut2) control of the LHb, comparing the role of inputs originating in the globus pallidus internal segment (GPi), and lateral hypothalamic area (LHA), respectively. We found that LHb-projecting LHA neurons, and not the proposed GABA/glutamate co-releasing GPi neurons, are responsible for encoding negative value. Monosynaptic rabies tracing of the presynaptic organization revealed a predominantly limbic input onto LHA Vglut2 neurons, while sensorimotor inputs were more prominent onto GABA/glutamate co-releasing GPi neurons. We further recorded the activity of LHA Vglut2 neurons, by imaging calcium dynamics in response to appetitive versus aversive events in conditioning paradigms. LHA Vglut2 neurons formed activity clusters representing distinct reward or aversion signals, including a population that responded to mild foot shocks and predicted aversive events. We found that the LHb-projecting LHA Vglut2 neurons encode negative valence and rapidly develop a prediction signal for negative events. These findings establish the glutamatergic LHA-LHb circuit as a critical node in value processing.
Assuntos
Aprendizagem da Esquiva/fisiologia , Habenula/fisiologia , Hipotálamo/fisiologia , Afeto/fisiologia , Animais , Dopamina/metabolismo , Fármacos Atuantes sobre Aminoácidos Excitatórios/metabolismo , Globo Pálido/fisiologia , Ácido Glutâmico/metabolismo , Habenula/metabolismo , Região Hipotalâmica Lateral/fisiologia , Hipotálamo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Vias Neurais/fisiologia , Neurônios/fisiologia , RecompensaRESUMO
Reward-seeking behavior is regulated by a diverse collection of inputs to the nucleus accumbens (NAc). The information encoded in each excitatory afferent to the NAc is unknown, in part because it is unclear when these pathways are active in relation to behavior. Here we compare the activity profiles of amygdala, hippocampal, and thalamic inputs to the NAc shell in mice performing a cued reward-seeking task using GCaMP-based fiber photometry. We find that the rostral and caudal ends of the NAc shell are innervated by distinct but intermingled populations of forebrain neurons that exhibit divergent feeding-related activity. In the rostral NAc shell, a coordinated network-wide reduction in excitatory drive correlates with feeding, and reduced input from individual pathways is sufficient to promote it. Overall, the data suggest that pathway-specific input activity at a population level may vary more across the NAc than between pathways.
Assuntos
Tonsila do Cerebelo/fisiologia , Comportamento Animal/fisiologia , Hipocampo/fisiologia , Núcleo Accumbens/fisiologia , Animais , Sinais (Psicologia) , Masculino , Camundongos Endogâmicos C57BL , Vias Neurais/fisiologia , Neurônios/fisiologia , Recompensa , Tálamo/fisiologiaRESUMO
Optogenetic tools have opened a rich experimental landscape for understanding neural function and disease. Here, we present the first validation of eight optogenetic constructs driven by recombinant adeno-associated virus (AAV) vectors and a WGA-Cre based dual injection strategy for projection targeting in a widely-used New World primate model, the common squirrel monkey Saimiri sciureus. We observed opsin expression around the local injection site and in axonal projections to downstream regions, as well as transduction to thalamic neurons, resembling expression patterns observed in macaques. Optical stimulation drove strong, reliable excitatory responses in local neural populations for two depolarizing opsins in anesthetized monkeys. Finally, we observed continued, healthy opsin expression for at least one year. These data suggest that optogenetic tools can be readily applied in squirrel monkeys, an important first step in enabling precise, targeted manipulation of neural circuits in these highly trainable, cognitively sophisticated animals. In conjunction with similar approaches in macaques and marmosets, optogenetic manipulation of neural circuits in squirrel monkeys will provide functional, comparative insights into neural circuits which subserve dextrous motor control as well as other adaptive behaviors across the primate lineage. Additionally, development of these tools in squirrel monkeys, a well-established model system for several human neurological diseases, can aid in identifying novel treatment strategies.
Assuntos
Rede Nervosa/cirurgia , Neurônios/metabolismo , Optogenética/instrumentação , Saimiri/genética , Animais , Axônios/metabolismo , Axônios/patologia , Dependovirus/genética , Humanos , Rede Nervosa/fisiologia , Opsinas/genética , Saimiri/cirurgia , Tálamo/fisiopatologia , Tálamo/cirurgiaRESUMO
Neurotransmitter switching in the adult mammalian brain occurs following photoperiod-induced stress, but the mechanism of regulation is unknown. Here, we demonstrate that elevated activity of dopaminergic neurons in the paraventricular nucleus of the hypothalamus (PaVN) in the adult rat is required for the loss of dopamine expression after long-day photoperiod exposure. The transmitter switch occurs exclusively in PaVN dopaminergic neurons that coexpress vesicular glutamate transporter 2 (VGLUT2), is accompanied by a loss of dopamine type 2 receptors (D2Rs) on corticotrophin-releasing factor (CRF) neurons, and can lead to increased release of CRF. Suppressing activity of all PaVN glutamatergic neurons decreases the number of inhibitory PaVN dopaminergic neurons, indicating homeostatic regulation of transmitter expression in the PaVN.
Assuntos
Encéfalo/metabolismo , Dopamina/metabolismo , Neurônios Dopaminérgicos/fisiologia , Luz , Neurotransmissores/metabolismo , Estresse Fisiológico , Animais , Encéfalo/patologia , Encéfalo/efeitos da radiação , Células Cultivadas , Hormônio Liberador da Corticotropina , Neurônios Dopaminérgicos/citologia , Hipotálamo/metabolismo , Hipotálamo/patologia , Hipotálamo/efeitos da radiação , Masculino , Neurotransmissores/efeitos da radiação , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/patologia , Núcleo Hipotalâmico Paraventricular/efeitos da radiação , Ratos , Ratos Long-Evans , Receptores Dopaminérgicos/metabolismo , Proteína Vesicular 2 de Transporte de Glutamato/metabolismoRESUMO
Experience-driven synaptic plasticity in the lateral amygdala is thought to underlie the formation of associations between sensory stimuli and an ensuing threat. However, how the central amygdala participates in such a learning process remains unclear. Here we show that PKC-δ-expressing central amygdala neurons are essential for the synaptic plasticity underlying learning in the lateral amygdala, as they convey information about the unconditioned stimulus to lateral amygdala neurons during fear conditioning.
Assuntos
Núcleo Central da Amígdala/fisiologia , Aprendizagem/fisiologia , Animais , Aprendizagem da Esquiva , Condicionamento Psicológico , Ingestão de Alimentos , Medo/psicologia , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/fisiologia , Optogenética , Técnicas de Patch-Clamp , Proteína Quinase C-delta/biossíntese , Proteína Quinase C-delta/genética , Transmissão Sináptica/fisiologia , Tálamo/fisiologiaRESUMO
The successful planning and execution of adaptive behaviors in mammals may require long-range coordination of neural networks throughout cerebral cortex. The neuronal implementation of signals that could orchestrate cortex-wide activity remains unclear. Here, we develop and apply methods for cortex-wide Ca2+ imaging in mice performing decision-making behavior and identify a global cortical representation of task engagement encoded in the activity dynamics of both single cells and superficial neuropil distributed across the majority of dorsal cortex. The activity of multiple molecularly defined cell types was found to reflect this representation with type-specific dynamics. Focal optogenetic inhibition tiled across cortex revealed a crucial role for frontal cortex in triggering this cortex-wide phenomenon; local inhibition of this region blocked both the cortex-wide response to task-initiating cues and the voluntary behavior. These findings reveal cell-type-specific processes in cortex for globally representing goal-directed behavior and identify a major cortical node that gates the global broadcast of task-related information.
Assuntos
Comportamento Animal/fisiologia , Tomada de Decisões/fisiologia , Lobo Frontal/fisiologia , Objetivos , Neocórtex/fisiologia , Neurônios/fisiologia , Animais , Cálcio/metabolismo , Lobo Frontal/metabolismo , Camundongos , Neocórtex/citologia , Neocórtex/metabolismo , Neurônios/metabolismo , Imagem Óptica , OptogenéticaRESUMO
Both humans and animals seek primary rewards in the environment, even when such rewards do not correspond to current physiological needs. An example of this is a dissociation between food-seeking behaviour and metabolic needs, a notoriously difficult-to-treat symptom of eating disorders. Feeding relies on distinct cell groups in the hypothalamus, the activity of which also changes in anticipation of feeding onset. The hypothalamus receives strong descending inputs from the lateral septum, which is connected, in turn, with cortical networks, but cognitive regulation of feeding-related behaviours is not yet understood. Cortical cognitive processing involves gamma oscillations, which support memory, attention, cognitive flexibility and sensory responses. These functions contribute crucially to feeding behaviour by unknown neural mechanisms. Here we show that coordinated gamma (30-90 Hz) oscillations in the lateral hypothalamus and upstream brain regions organize food-seeking behaviour in mice. Gamma-rhythmic input to the lateral hypothalamus from somatostatin-positive lateral septum cells evokes food approach without affecting food intake. Inhibitory inputs from the lateral septum enable separate signalling by lateral hypothalamus neurons according to their feeding-related activity, making them fire at distinct phases of the gamma oscillation. Upstream, medial prefrontal cortical projections provide gamma-rhythmic inputs to the lateral septum; these inputs are causally associated with improved performance in a food-rewarded learning task. Overall, our work identifies a top-down pathway that uses gamma synchronization to guide the activity of subcortical networks and to regulate feeding behaviour by dynamic reorganization of functional cell groups in the hypothalamus.
Assuntos
Comportamento Alimentar/fisiologia , Ritmo Gama/fisiologia , Hipotálamo/fisiologia , Animais , Ingestão de Alimentos/fisiologia , Ingestão de Alimentos/psicologia , Metabolismo Energético/fisiologia , Comportamento Alimentar/psicologia , Hipotálamo/citologia , Aprendizagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia , Recompensa , Somatostatina/metabolismoRESUMO
A central goal of neuroscience is to understand how populations of neurons coordinate and cooperate in order to give rise to perception, cognition, and action. Nonhuman primates (NHPs) are an attractive model with which to understand these mechanisms in humans, primarily due to the strong homology of their brains and the cognitively sophisticated behaviors they can be trained to perform. Using electrode recordings, the activity of one to a few hundred individual neurons may be measured electrically, which has enabled many scientific findings and the development of brain-machine interfaces. Despite these successes, electrophysiology samples sparsely from neural populations and provides little information about the genetic identity and spatial micro-organization of recorded neurons. These limitations have spurred the development of all-optical methods for neural circuit interrogation. Fluorescent calcium signals serve as a reporter of neuronal responses, and when combined with post-mortem optical clearing techniques such as CLARITY, provide dense recordings of neuronal populations, spatially organized and annotated with genetic and anatomical information. Here, we advocate that this methodology, which has been of tremendous utility in smaller animal models, can and should be developed for use with NHPs. We review here several of the key opportunities and challenges for calcium-based optical imaging in NHPs. We focus on motor neuroscience and brain-machine interface design as representative domains of opportunity within the larger field of NHP neuroscience.
Assuntos
Interfaces Cérebro-Computador , Sinalização do Cálcio , Cálcio/análise , Conectoma/métodos , Processamento de Imagem Assistida por Computador/métodos , Microscopia Intravital/métodos , Córtex Motor/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Primatas/anatomia & histologia , Análise de Célula Única , Algoritmos , Animais , Proteínas de Bactérias/análise , Proteínas de Bactérias/genética , Comportamento Animal , Conectoma/instrumentação , Técnicas Citológicas/instrumentação , Estimulação Elétrica , Corantes Fluorescentes , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética , Imageamento Tridimensional , Microscopia Intravital/instrumentação , Proteínas Luminescentes/análise , Proteínas Luminescentes/genética , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Modelos Neurológicos , Atividade Motora , Córtex Motor/citologia , Rede Nervosa/ultraestrutura , Neurônios/química , Neurônios/ultraestrutura , Primatas/fisiologia , Transdução Genética , VigíliaRESUMO
The hypothalamus contains the highest diversity of neurons in the brain. Many of these neurons can co-release neurotransmitters and neuropeptides in a use-dependent manner. Investigators have hitherto relied on candidate protein-based tools to correlate behavioral, endocrine and gender traits with hypothalamic neuron identity. Here we map neuronal identities in the hypothalamus by single-cell RNA sequencing. We distinguished 62 neuronal subtypes producing glutamatergic, dopaminergic or GABAergic markers for synaptic neurotransmission and harboring the ability to engage in task-dependent neurotransmitter switching. We identified dopamine neurons that uniquely coexpress the Onecut3 and Nmur2 genes, and placed these in the periventricular nucleus with many synaptic afferents arising from neuromedin S+ neurons of the suprachiasmatic nucleus. These neuroendocrine dopamine cells may contribute to the dopaminergic inhibition of prolactin secretion diurnally, as their neuromedin S+ inputs originate from neurons expressing Per2 and Per3 and their tyrosine hydroxylase phosphorylation is regulated in a circadian fashion. Overall, our catalog of neuronal subclasses provides new understanding of hypothalamic organization and function.
Assuntos
Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Hipotálamo/metabolismo , Neuropeptídeos/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Animais , Imuno-Histoquímica/métodos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurotransmissores/fisiologia , Núcleo Supraquiasmático/metabolismo , Transmissão Sináptica/fisiologiaRESUMO
Thalamic relay neurons have well-characterized dual firing modes: bursting and tonic spiking. Studies in brain slices have led to a model in which rhythmic synchronized spiking (phasic firing) in a population of relay neurons leads to hyper-synchronous oscillatory cortico-thalamo-cortical rhythms that result in absence seizures. This model suggests that blocking thalamocortical phasic firing would treat absence seizures. However, recent in vivo studies in anesthetized animals have questioned this simple model. Here we resolve this issue by developing a real-time, mode-switching approach to drive thalamocortical neurons into or out of a phasic firing mode in two freely behaving genetic rodent models of absence epilepsy. Toggling between phasic and tonic firing in thalamocortical neurons launched and aborted absence seizures, respectively. Thus, a synchronous thalamocortical phasic firing state is required for absence seizures, and switching to tonic firing rapidly halts absences. This approach should be useful for modulating other networks that have mode-dependent behaviors.
Assuntos
Córtex Cerebral/fisiopatologia , Epilepsia Tipo Ausência/fisiopatologia , Rede Nervosa/fisiopatologia , Neurônios/fisiologia , Tálamo/fisiopatologia , Animais , Ondas Encefálicas , Córtex Cerebral/citologia , Modelos Animais de Doenças , Eletrocorticografia , Epilepsia/fisiopatologia , Camundongos , Vias Neurais , Optogenética , Técnicas de Patch-Clamp , Ratos , Tálamo/citologiaRESUMO
Spatially targeted, genetically-specific strategies for sustained inhibition of nociceptors may help transform pain science and clinical management. Previous optogenetic strategies to inhibit pain have required constant illumination, and chemogenetic approaches in the periphery have not been shown to inhibit pain. Here, we show that the step-function inhibitory channelrhodopsin, SwiChR, can be used to persistently inhibit pain for long periods of time through infrequent transdermally delivered light pulses, reducing required light exposure by >98% and resolving a long-standing limitation in optogenetic inhibition. We demonstrate that the viral expression of the hM4D receptor in small-diameter primary afferent nociceptor enables chemogenetic inhibition of mechanical and thermal nociception thresholds. Finally, we develop optoPAIN, an optogenetic platform to non-invasively assess changes in pain sensitivity, and use this technique to examine pharmacological and chemogenetic inhibition of pain.
Assuntos
Channelrhodopsins/genética , Clozapina/análogos & derivados , Optogenética/métodos , Dor/tratamento farmacológico , Dor/radioterapia , Animais , Células Cultivadas , Clozapina/administração & dosagem , Clozapina/uso terapêutico , Terapia Combinada , Modelos Animais de Doenças , Terapia com Luz de Baixa Intensidade , Camundongos , NociceptividadeRESUMO
Serotonin (also known as 5-hydroxytryptamine (5-HT)) is a neurotransmitter that has an essential role in the regulation of emotion. However, the precise circuits have not yet been defined through which aversive states are orchestrated by 5-HT. Here we show that 5-HT from the dorsal raphe nucleus (5-HTDRN) enhances fear and anxiety and activates a subpopulation of corticotropin-releasing factor (CRF) neurons in the bed nucleus of the stria terminalis (CRFBNST) in mice. Specifically, 5-HTDRN projections to the BNST, via actions at 5-HT2C receptors (5-HT2CRs), engage a CRFBNST inhibitory microcircuit that silences anxiolytic BNST outputs to the ventral tegmental area and lateral hypothalamus. Furthermore, we demonstrate that this CRFBNST inhibitory circuit underlies aversive behaviour following acute exposure to selective serotonin reuptake inhibitors (SSRIs). This early aversive effect is mediated via the corticotrophin-releasing factor type 1 receptor (CRF1R, also known as CRHR1), given that CRF1R antagonism is sufficient to prevent acute SSRI-induced enhancements in aversive learning. These results reveal an essential 5-HTDRNâCRFBNST circuit governing fear and anxiety, and provide a potential mechanistic explanation for the clinical observation of early adverse events to SSRI treatment in some patients with anxiety disorders.
Assuntos
Tonsila do Cerebelo/metabolismo , Ansiedade/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Medo/fisiologia , Serotonina/metabolismo , Tálamo/metabolismo , Tonsila do Cerebelo/efeitos dos fármacos , Animais , Ansiedade/induzido quimicamente , Transtornos de Ansiedade/induzido quimicamente , Núcleo Dorsal da Rafe/efeitos dos fármacos , Núcleo Dorsal da Rafe/metabolismo , Medo/efeitos dos fármacos , Feminino , Fluoxetina/efeitos adversos , Fluoxetina/farmacologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Masculino , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Optogenética , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Inibidores Seletivos de Recaptação de Serotonina/efeitos adversos , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Tálamo/efeitos dos fármacos , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/metabolismoRESUMO
In many vertebrate species, certain individuals will seek out opportunities for aggression, even in the absence of threat-provoking cues. Although several brain areas have been implicated in the generation of attack in response to social threat, little is known about the neural mechanisms that promote self-initiated or 'voluntary' aggression-seeking when no threat is present. To explore this directly, we utilized an aggression-seeking task in which male mice self-initiated aggression trials to gain brief and repeated access to a weaker male that they could attack. In males that exhibited rapid task learning, we found that the ventrolateral part of the ventromedial hypothalamus (VMHvl), an area with a known role in attack, was essential for aggression-seeking. Using both single-unit electrophysiology and population optical recording, we found that VMHvl neurons became active during aggression-seeking and that their activity tracked changes in task learning and extinction. Inactivation of the VMHvl reduced aggression-seeking behavior, whereas optogenetic stimulation of the VMHvl accelerated moment-to-moment aggression-seeking and intensified future attack. These data demonstrate that the VMHvl can mediate both acute attack and flexible seeking actions that precede attack.
Assuntos
Agressão/fisiologia , Agressão/psicologia , Hipotálamo/fisiologia , Atividade Motora/fisiologia , Optogenética/métodos , Comportamento Social , Animais , Masculino , Camundongos , Camundongos Endogâmicos BALB CRESUMO
How the brain selects appropriate sensory inputs and suppresses distractors is unknown. Given the well-established role of the prefrontal cortex (PFC) in executive function, its interactions with sensory cortical areas during attention have been hypothesized to control sensory selection. To test this idea and, more generally, dissect the circuits underlying sensory selection, we developed a cross-modal divided-attention task in mice that allowed genetic access to this cognitive process. By optogenetically perturbing PFC function in a temporally precise window, the ability of mice to select appropriately between conflicting visual and auditory stimuli was diminished. Equivalent sensory thalamocortical manipulations showed that behaviour was causally dependent on PFC interactions with the sensory thalamus, not sensory cortex. Consistent with this notion, we found neurons of the visual thalamic reticular nucleus (visTRN) to exhibit PFC-dependent changes in firing rate predictive of the modality selected. visTRN activity was causal to performance as confirmed by bidirectional optogenetic manipulations of this subnetwork. Using a combination of electrophysiology and intracellular chloride photometry, we demonstrated that visTRN dynamically controls visual thalamic gain through feedforward inhibition. Our experiments introduce a new subcortical model of sensory selection, in which the PFC biases thalamic reticular subnetworks to control thalamic sensory gain, selecting appropriate inputs for further processing.