Reduced Responsiveness to Long-Term Monocular Deprivation of Parvalbumin Neurons Assessed by c-Fos Staining in Rat Visual Cortex

Marco Mainardi,Lamberto Maffei,Silvia Landi,Tommaso Pizzorusso,Nicoletta Berardi,Bernhard Baune

doi:10.1371/journal.pone.0004342

Marco Mainardi, Lamberto Maffei + Show 4 more

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https://doi.org/10.1371/journal.pone.0004342

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Abstract

BackgroundIt is generally assumed that visual cortical cells homogeneously shift their ocular dominance (OD) in response to monocular deprivation (MD), however little experimental evidence directly supports this notion. By using immunohistochemistry for the activity-dependent markers c-Fos and Arc, coupled with staining for markers of inhibitory cortical sub-populations, we studied whether long-term MD initiated at P21 differentially affects visual response of inhibitory neurons in rat binocular primary visual cortex.Methodology/Principal FindingsThe inhibitory markers GAD67, parvalbumin (PV), calbindin (CB) and calretinin (CR) were used. Visually activated Arc did not colocalize with PV and was discarded from further studies. MD decreased visually induced c-Fos activation in GAD67 and CR positive neurons. The CB population responded to MD with a decrease of CB expression, while PV cells did not show any effect of MD on c-Fos expression. The persistence of c-Fos expression induced by deprived eye stimulation in PV cells is not likely to be due to a particularly low threshold for activity-dependent c-Fos induction. Indeed, c-Fos induction by increasing concentrations of the GABAA antagonist picrotoxin in visual cortical slices was similar between PV cells and the other cortical neurons.ConclusionThese data indicate that PV cells are particularly refractory to MD, suggesting that different cortical subpopulation may show different response to MD.

Highlights

It is well known that monocular deprivation (MD) shifts the ocular dominance (OD) of neurons in the binocular portion of the primary visual cortex in favour of the nondeprived eye during a sensitive period [1]
These data indicate that PV cells are refractory to MD, suggesting that different cortical subpopulation may show different response to MD
Recent data have shown that some cortical cells shift their response in favour of the deprived eye, with the direction of the shift critically depending on the amount of open-eye input and the net visual drive experienced during MD [2]

Summary

Introduction

It is well known that MD shifts the OD of neurons in the binocular portion of the primary visual cortex in favour of the nondeprived eye during a sensitive period [1]. It is still poorly understood whether all cortical cells shift in response to MD. By using immunohistochemistry for the activity-dependent markers c-Fos and Arc, coupled with staining for markers of inhibitory cortical sub-populations, we studied whether long-term MD initiated at P21 differentially affects visual response of inhibitory neurons in rat binocular primary visual cortex

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