Parvalbumin-Expressing GABAergic Neurons in Primary Motor Cortex Signal Reaching

Publication date: 11 July 2017
Source:Cell Reports, Volume 20, Issue 2
Author(s): Luc Estebanez, Diana Hoffmann, Birgit C. Voigt, James F.A. Poulet
The control of targeted reaching is thought to be shaped by distinct subtypes of local GABAergic inhibitory neurons in primary forelimb motor cortex (M1). However, little is known about their action potential firing dynamics during reaching. To address this, we recorded the activity of parvalbumin-expressing (PV+) GABAergic neurons identified from a larger population of fast-spiking units and putative excitatory regular-spiking units in layer 5 of the mouse forelimb M1 during an M1-dependent, sensory-triggered reaching task. PV+ neurons showed short latency responses to the acoustic cue and vibrotactile trigger stimulus and an increase in firing at reaching onset that scaled with the amplitude of reaching. Unexpectedly, PV+ neurons fired before regular-spiking units at reach onset and showed high overall firing rates during both sensory-triggered and spontaneous reaches. Our data suggest that increasing M1 PV+ neuron firing rates may play a role in the initiation of voluntary reaching.

Graphical abstract

Teaser

Estebanez et al. use optogenetics and electrophysiology to study the activity of parvalbumin-expressing GABAergic neurons in the forelimb primary motor cortex during a reaching task in head-fixed mice. They report that PV+ neurons show robust increases in firing at reaching onset that occur before the activity of putative pyramidal neurons.


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