RESUMEN
The flow of neural activity across the neocortex during active sensory discrimination is constrained by task-specific cognitive demands, movements, and internal states. During behavior, the brain appears to sample from a broad repertoire of activation motifs. Understanding how these patterns of local and global activity are selected in relation to both spontaneous and task-dependent behavior requires in-depth study of densely sampled activity at single neuron resolution across large regions of cortex. In a significant advance toward this goal, we developed procedures to record mesoscale 2-photon Ca2+ imaging data from two novel in vivo preparations that, between them, allow simultaneous access to nearly all of the mouse dorsal and lateral neocortex. As a proof of principle, we aligned neural activity with both behavioral primitives and high-level motifs to reveal the existence of large populations of neurons that coordinated their activity across cortical areas with spontaneous changes in movement and/or arousal. The methods we detail here facilitate the identification and exploration of widespread, spatially heterogeneous neural ensembles whose activity is related to diverse aspects of behavior.
RESUMEN
The flow of neural activity across the neocortex during active sensory discrimination is constrained by task-specific cognitive demands, movements, and internal states. During behavior, the brain appears to sample from a broad repertoire of activation motifs. Understanding how these patterns of local and global activity are selected in relation to both spontaneous and task-dependent behavior requires in-depth study of densely sampled activity at single neuron resolution across large regions of cortex. In a significant advance toward this goal, we developed procedures to record mesoscale 2-photon Ca2+ imaging data from two novel in vivo preparations that, between them, allow for simultaneous access to nearly all 0f the mouse dorsal and lateral neocortex. As a proof of principle, we aligned neural activity with both behavioral primitives and high-level motifs to reveal the existence of large populations of neurons that coordinated their activity across cortical areas with spontaneous changes in movement and/or arousal. The methods we detail here facilitate the identification and exploration of widespread, spatially heterogeneous neural ensembles whose activity is related to diverse aspects of behavior.
Asunto(s)
Conducta Animal , Neuronas , Vigilia , Animales , Ratones , Vigilia/fisiología , Neuronas/fisiología , Conducta Animal/fisiología , Neocórtex/fisiología , Neocórtex/diagnóstico por imagen , Masculino , Calcio/metabolismo , Microscopía de Fluorescencia por Excitación Multifotónica/métodosRESUMEN
Parvalbumin (PV)-expressing interneurons mediate fast inhibition of principal neurons in many brain areas; however, long-term plasticity at PV-interneuron output synapses has been less well studied. In the auditory cortex, thalamic inputs drive reliably timed action potentials (APs) in principal neurons and PV-interneurons. Using paired recordings in the input layer of the mouse auditory cortex, we found a marked spike-timing-dependent plasticity (STDP) at PV-interneuron output synapses. Long-term potentiation of inhibition (iLTP) is observed upon postsynaptic (principal neuron) then presynaptic (PV-interneuron) AP firing. The opposite AP order causes GABAB-mediated long-term depression of inhibition (iLTD), which is developmentally converted to iLTP in an experience-dependent manner. Genetic deletion of GABAB receptors in principal neurons suppressed iLTD and produced deficits in auditory map remodeling. Output synapses of PV-interneurons thus show marked STDP, and one limb of this plasticity, GABAB-dependent iLTD, is a candidate mechanism for disinhibition during auditory critical period plasticity.