Power-Law Input-Output Transfer Functions Explain the Contrast-Response and Tuning Properties of Neurons in Visual Cortex

1. PLoS Comput Biol. 2011 Feb;7(2):e1001078. doi: 10.1371/journal.pcbi.1001078.
Epub 2011 Feb 24.

Power-law input-output transfer functions explain the contrast-response and
tuning properties of neurons in visual cortex.

Persi E(1), Hansel D, Nowak L, Barone P, van Vreeswijk C.

Author information:
(1)Laboratoire de Neurophysique et Physiologie, Université Paris Descartes,
Paris, France.

We develop a unified model accounting simultaneously for the contrast invariance
of the width of the orientation tuning curves (OT) and for the sigmoidal shape
of the contrast response function (CRF) of neurons in the primary visual cortex
(V1). We determine analytically the conditions for the structure of the afferent
LGN and recurrent V1 inputs that lead to these properties for a hypercolumn
composed of rate based neurons with a power-law transfer function. We
investigate what are the relative contributions of single neuron and network
properties in shaping the OT and the CRF. We test these results with numerical
simulations of a network of conductance-based model (CBM) neurons and we
demonstrate that they are valid and more robust here than in the rate model. The
results indicate that because of the acceleration in the transfer function,
described here by a power-law, the orientation tuning curves of V1 neurons are
more tuned, and their CRF is steeper than those of their inputs. Last, we show
that it is possible to account for the diversity in the measured CRFs by
introducing heterogeneities either in single neuron properties or in the input
to the neurons. We show how correlations among the parameters that characterize
the CRF depend on these sources of heterogeneities. Comparison with experimental
data suggests that both sources contribute nearly equally to the diversity of
CRF shapes observed in V1 neurons.

DOI: 10.1371/journal.pcbi.1001078
PMCID: PMC3044767
PMID: 21390280 [Indexed for MEDLINE]

Conflict of interest statement: The authors have declared that no competing
interests exist.

Auteurs Bordeaux Neurocampus