Relationship between Morphology, in vivo electrophysiology, molecular identity and thalamocortical input of cortical inhibitory neurons

Luis Fernando Messore1, Jason M Guest1, Felipe Yanez1, Rajeevan Narayanan1, Marcel Oberlaender1

1 caesar

Inhibitory interneurons in the neocortex show a vast diversity in their morphological and electrophysiological properties. How such cellular diversity extends to activity patterns in the living animal is not yet fully understood. In particular, measurements in the deep layers are scares given the limited accessibility with current imaging techniques. Here we combine in vivo cell-attached recordings of inhibitory neurons in layers 4 and 5 of the rodent primary somatosensory cortex, with post-hoc morphological reconstruction. In conjunction, we characterize the inhibitory neurons in term of their molecular identity, the degree of synaptic input from primary thalamocortical nuclei and activity patterns both from sensory evoked and optogenetic activation. Our data provides a quantitative assessment at single cell resolution of the relationships between thalamocortical input, dendrite/axon morphology, layer location, molecular identity and the in-vivo activity of these neurons. This research will aid towards a comprehensive understanding of how the different parameters of this neurons relate to their embedding into the thalamocortical and intracortical microcircuits in the neocortex.