Invariant computations in local cortical networks with balanced excitation and inhibition.
Cortical computations critically involve local neuronal circuits. The computations are often invariant across a cortical area yet are carried out by networks that can vary widely within an area according to its functional architecture. Here we demonstrate a mechanism by which orientation selectivity is computed invariantly in cat primary visual cortex across an orientation preference map that provides a wide diversity of local circuits. Visually evoked excitatory and inhibitory synaptic conductances are balanced exquisitely in cortical neurons and thus keep the spike response sharply tuned at all map locations. This functional balance derives from spatially isotropic local connectivity of both excitatory and inhibitory cells. Modeling results demonstrate that such covariation is a signature of recurrent rather than purely feed-forward processing and that the observed isotropic local circuit is sufficient to generate invariant spike tuning.
Mariño
Jorge
J
Department of Brain and Cognitive Sciences and Picower Center for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Schummers
James
J
Lyon
David C
DC
Schwabe
Lars
L
Beck
Oliver
O
Wiesing
Peter
P
Obermayer
Klaus
K
Sur
Mriganka
M
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D001931:Brain Mapping; D002415:Cats; D002452:Cell Count / Q000379:methods; D002772:Cholera Toxin / Q000378:metabolism; D003198:Computer Simulation; D003952:Diagnostic Imaging / Q000379:methods; D007150:Immunohistochemistry / Q000379:methods; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009474:Neurons / Q000502:physiology* / Q000528:radiation effects; D009949:Orientation / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D010775:Photic Stimulation / Q000379:methods; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology / Q000528:radiation effects; D014793:Visual Cortex / Q000166:cytology* / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D005680:gamma-Aminobutyric Acid; D002772:Cholera Toxin