Early Cross-modal Plasticity in Adults

Abstract

It is known that, after a prolonged period of visual deprivation, the adult visual cortex can be recruited for nonvisual processing, reflecting cross-modal plasticity. Here, we investigated whether cross-modal plasticity can occur at short timescales in the typical adult brain by comparing the interaction between vision and touch during binocular rivalry before and after a brief period of monocular deprivation, which strongly alters ocular balance favoring the deprived eye. While viewing dichoptically two gratings of orthogonal orientation, participants were asked to actively explore a haptic grating congruent in orientation to one of the two rivalrous stimuli. We repeated this procedure before and after 150 min of monocular deprivation. We first confirmed that haptic stimulation interacted with vision during rivalry promoting dominance of the congruent visuohaptic stimulus and that monocular deprivation increased the deprived eye and decreased the nondeprived eye dominance. Interestingly, after deprivation, we found that the effect of touch did not change for the nondeprived eye, whereas it disappeared for the deprived eye, which was potentiated after deprivation. The absence of visuo-haptic interaction for the deprived eye lasted for over 1 hr and was not attributable to a masking induced by the stronger response of the deprived eye as confirmed by a control experiment. Taken together, our results demonstrate that the adult human visual cortex retains a high degree of cross-modal plasticity, which can occur even at very short timescales.

Recalibrating the body: visuotactile ventriloquism aftereffect

“…These results are consistent with recent findings demonstrating cross-modal plasticity in adulthood, a finding that emerges from studies investigating the effect of visual deprivation on the haptic modality ( Kauffman, Théoret & Pascual-Leone, 2002 ; Merabet et al, 2008 ; Lo Verde, Morrone & Lunghi, 2016 ). In those studies, the emphasis is placed on the fact that an unused modality can lead to its cortical machinery being used to aid task performance in another modality.…”

Brief period of monocular deprivation drives changes in audiovisual temporal perception

“…Second, it is plausible that the changes observed in the TBW after monocular deprivation could arise from genuine cross-modal plasticity, reflecting changes in the tendency to bind the audiovisual stimulus pair. In a very interesting study, Lo Verde, Morrone, and Lunghi (2017) discovered using a binocular rivalry paradigm that, after monocular deprivation, the effect of visuo-haptic interaction on perceptual dominance disappeared for the deprived eye, which was potentiated in the visual domain, but was not affected for the nondeprived eye, which was weakened. In a separate control experiment where a postdeprivation effect was simulated by increasing the intensity of the visual stimulus for one eye and decreasing the intensity for the other eye, this unequal effect of monocular deprivation on cross-modal interaction for the deprived and nondeprived eyes disappeared, indicating that the effects on monocular deprivation were due to mechanisms that exceeded changes in contrast gain of the deprived eye ( Lo Verde et al, 2017 ).…”

Visual Cortical Plasticity in Retinitis Pigmentosa

“…However, after approximately 1 year, the colonized V1 response of tactile signal is reduced in one subject 28 and the aberrant V1 response to flashes of light is increased in three other subjects. 29 Given that binocular rivalry can be modulated by tactile signals [81][82][83][84] and can reveal the small changes of tactile modulation of V1 responses after short-term monocular deprivation in adult humans, 85 it would be useful to test directly the hypothesis of cross-modal recruitment in RP subjects in future studies.…”