Ipsilateral Eye Cortical Maps Are Uniquely Sensitive to Binocular Plasticity

Abstract

Faguet J, Maranhao B, Smith SL, Trachtenberg JT. Ipsilateral eye cortical maps are uniquely sensitive to binocular plasticity. J Neurophysiol 101: 855-861, 2009. First published December 3, 2008 doi:10.1152/jn.90893.2008. In the cerebral cortex, neuronal circuits are first laid down by intrinsic mechanisms and then refined by experience. In the canonical model, this refinement is driven by activity-dependent competition between inputs for some limited cortical resource. Here we examine this idea in the mouse visual cortex at the peak of the critical period for experience-dependent plasticity. By imaging intrinsic optical responses, we mapped the strength and size of each eye's cortical representation in normal mice, mice that had been deprived of patterned vision uni-or bilaterally, and in mice in which the contralateral eye had been removed. We find that for both eyes, a period of visual deprivation results in a loss of cortical responsiveness to stimulation through the deprived eye. In addition, the ipsilateral eye pathway is affected by the quality of vision through the opposite eye. Our findings indicate that although both contra-and ipsilateral eye pathways require visual experience for their maintenance, ipsilateral eye projections bear an additional, unique sensitivity to binocular interactions.

A Theory of the Transition to Critical Period Plasticity: Inhibition Selectively Suppresses Spontaneous Activity

“…To model MD, in which the visual stimulus reaches the contralateral eye only after penetration through the closed eyelid, we assume the visual component of the closed-eye is blurred (Faguet et al, 2009) and weakened by half. Such blurring is known to influence V1 development (White et al, 2001; Akerman et al, 2002), and has been suggested to underlie the slowing of retinotopic development by MD but not monocular inactivation (MI) during the pre-CP (Smith and Trachtenberg, 2007).…”

“…2C). The refinement decreased due to the broadly correlated residual visual stimulus through the deprived eyelid (Faguet et al, 2009). Despite a dramatic change in the distance over which visual inputs were correlated, the RF widened only by about 30% (Fig.…”

“…Closing one eye greatly broadens the spatial correlations between inputs from that eye (Faguet et al, 2009). Broader correlations yield less retinotopic refinement of receptive fields (RFs) under Hebbian (correlation-based) mechanisms of synaptic plasticity.…”

Layer- and Cell-Type-Specific Subthreshold and Suprathreshold Effects of Long-Term Monocular Deprivation in Rat Visual Cortex

“…However, loss of responsiveness occurs also during complete visual deprivations (Wiesel and Hubel, 1965;Freeman et al, 1981;Kaneko et al, 2008;Faguet et al, 2009;Iurilli et al, 2011). In addition, depression of closedeye responses and potentiation of openeye responses are two temporally (Mioche and Singer, 1989;Frenkel and Bear, 2004) and mechanistically (Heynen et al, 2003;Kaneko et al, 2008) distinct processes that can occur independently (Yoon et al, 2009).…”

Impaired Face Processing in Early Monocular Deprivation from Enucleation

“…33 Contralateral eye enucleation in mice accelerates the improvement of retinotopic organization (cortical refinement) and increases responsive area in V1 (cortical reorganization). 16,34 Compared with eyelid suture, postnatal ME greatly reduces ocular dominance columns associated with the enucleated eye in monkeys. 35 Prenatal ME obliterates LGN layer segregation and ocular dominance in area V1 of monkeys.…”