RT Journal Article
SR Electronic
T1 Laminarly Orthogonal Excitation of Fast-Spiking and Low-Threshold-Spiking Interneurons in Mouse Motor Cortex
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 7021
OP 7033
DO 10.1523/JNEUROSCI.0011-12.2012
VO 32
IS 20
A1 Apicella, Alfonso J.
A1 Wickersham, Ian R.
A1 Seung, H. Sebastian
A1 Shepherd, Gordon M. G.
YR 2012
UL http://www.jneurosci.org/content/32/20/7021.abstract
AB In motor cortex, long-range output to subcortical motor circuits depends on excitatory and inhibitory inputs converging on projection neurons in layers 5A/B. How interneurons interconnect with these projection neurons, and whether these microcircuits are interneuron and/or projection specific, is unclear. We found that fast-spiking interneurons received strong intralaminar (horizontal) excitation from pyramidal neurons in layers 5A/B including corticostriatal and corticospinal neurons, implicating them in mediating disynaptic recurrent, feedforward, and feedback inhibition within and across the two projection classes. Low-threshold-spiking (LTS) interneurons were instead strongly excited by descending interlaminar (vertical) input from layer 2/3 pyramidal neurons, implicating them in mediating disynaptic feedforward inhibition to both projection classes. Furthermore, in a novel pattern, lower layer 2/3 preferentially excited interneurons in one layer (5A/LTS) and excitatory neurons in another (5B/corticospinal). Thus, these inhibitory microcircuits in mouse motor cortex follow an orderly arrangement that is laminarly orthogonalized by interneuron-specific, projection-nonspecific connectivity.