Differential behavioral engagement of inhibitory interneuron subtypes in the zebra finch brain.

Inhibitory interneurons are highly heterogeneous circuit elements often characterized by cell biological properties, but how these factors relate to specific roles underlying complex behavior remains poorly understood. Using chronic silicon probe recordings, we demonstrate that distinct interneuron groups perform different inhibitory roles within HVC, a song production circuit in the zebra finch forebrain. To link these functional subtypes to molecular identity, we performed two-photon targeted electrophysiological recordings of HVC interneurons followed by post hoc immunohistochemistry of subtype-specific markers.

Pyramidal neurons proportionately alter the identity and survival of specific cortical interneuron subtypes.

The mammalian cerebral cortex comprises a complex neuronal network that maintains a delicate balance between excitatory neurons and inhibitory interneurons. Previous studies, including our own research, have shown that specific interneuron subtypes are closely associated with particular pyramidal neuron types, forming stereotyped local inhibitory microcircuits. However, the developmental processes that establish these precise networks are not well understood.

An enhancer-AAV toolbox to target and manipulate distinct interneuron subtypes.

In recent years, we and others have identified a number of enhancers that, when incorporated into rAAV vectors, can restrict the transgene expression to particular neuronal populations. Yet, viral tools to access and manipulate fine neuronal subtypes are still limited. Here, we performed systematic analysis of single cell genomic data to identify enhancer candidates for each of the cortical interneuron subtypes.

Pyramidal neurons proportionately alter the identity and survival of specific cortical interneuron subtypes.

The mammalian cerebral cortex comprises a complex neuronal network that maintains a delicate balance between excitatory neurons and inhibitory interneurons. Previous studies, including our own research, have shown that specific interneuron subtypes are closely associated with particular pyramidal neuron types, forming stereotyped local inhibitory microcircuits. However, the developmental processes that establish these precise networks are not well understood.

Interneuron Diversity: How Form Becomes Function.

A persistent question in neuroscience is how early neuronal subtype identity is established during the development of neuronal circuits. Despite significant progress in the transcriptomic characterization of cortical interneurons, the mechanisms that control the acquisition of such identities as well as how they relate to function are not clearly understood. Accumulating evidence indicates that interneuron identity is achieved through the interplay of intrinsic genetic and activity-dependent programs.