Visually evoked potential plasticity

One of the methods for evoking plasticity in the visual system is repeated stimulation with appropriate visual stimuli. Repeated exposure to sensory stimuli can induce neuronal network changes in the cortical circuits and improve the perception of these stimuli in the primary visual cortex (V1). The aim of our studies was to investigate the effect of repetitive visual training on the magnitude of visual responses in the primary visual cortex and in the superior colliculus (SC), the subcortical structure of the extrageniculate visual pathway in rats. Our study showed that a three-hour, passive visual training with light flashes enhanced visual responses both at the cortical level and in the superior colliculus. The next part of our study focused on distinguishing which input projection is responsible for the observed training effect in the SC, especially whether the increase of collicular response depends on the enhancement in the V1. The SC receives information both from the retina and from layer 5 of the V1. The experiment with pharmacological blocking of V1 did not suppress training-related plasticity in the SC. These results for the first time identified the superior colliculus as a possible target for training strategies to improve the efficiency of the visual process; e.g., in the case of primary visual cortex injuries.


dr Katarzyna Kordecka, e-mail: kkordecka@ichf.edu.pl


Cortical Inactivation Does Not Block Response Enhancement in the Superior Colliculus

Katarzyna Kordecka, Andrzej T. Foik, Agnieszka Wierzbicka and Wioletta J. Waleszczyk