In contrast to somatosensory cortex (SI), where the pervasiveness of reorganizational capacities is well-established, plasticity
of receptive fields (RFs) of adult primary visual cortex (VI) remains controversial. To investigate RF plasticity in VI of
adult rats, we here used intracortical microstimulation (ICMS) to overcome particularities related to stimulus presentation
and training procedures which limit comparison across modalities. Our results show that VI RFs can be altered by ICMS; however,
changes depended on the pre-ICMS RF size. Initially small RFs expanded after 2 h of ICMS with little signs of recovery within
the next hours, while initially large RFs remained unaffected. Inspection of the time course of neuron responses revealed,
however, that in large RFs early response components were enhanced, while late response components were reduced resulting
in changes of the spatiotemporal RF properties. Although plastic changes in VI showed a substantial heterogeneity, our results
indicate a capacity of VI neurons to undergo plastic changes comparable to SI neurons. However, the magnitude and aspects
of reversibility appeared to be different suggesting a significant modality-specificity of reorganizational changes of cortical
sensory neurons.
Keywords Intracortical microstimulation - Rat - Receptive field - Visual cortex - Plasticity - Spatiotemporal receptive field