In the present study, we investigated the effect of short-term visual deprivation on discriminative touch, cardiac interoception, and thermosensation by asking 64 healthy volunteers to perform four behavioral tasks. The experimental group contained 32 subjects who were blindfolded and kept in complete darkness for 110 minutes, while the control group consisted of 32 volunteers who were not blindfolded but were otherwise kept under identical experimental conditions. Both groups performed the required tasks three times: before and directly after deprivation (or control) and after an additional washout period of 40 minutes, in which all participants were exposed to normal light conditions. Our results showed that short-term visual deprivation had no effect on any of the senses tested. This finding suggests that short-term visual deprivation does not modulate basic bodily senses and extends this principle beyond tactile processing to the interoceptive modalities of cardiac and thermal sensations.
Progressive loss of plasticity during development prevents refined circuits from regressing to an immature state and is thought to depend on maturation of GABAergic inhibition. For example, a gradual reduction in size of visual receptive fields (RFs) occurs in the superior colliculus (SC) during development. Maintenance of the refined state throughout adulthood requires early light exposure. Here we investigate the potential role of changes in long- or short-term plasticity in experience-dependent maintenance of refined RFs. Using an acute SC slice preparation, we found that long-term plasticity was not affected by visual deprivation, indicating that it does not underlie deprivation-induced RF enlargement. In contrast, visual deprivation altered short-term plasticity in an unexpected way. Specifically, GABAB receptor (GABABR)-mediated paired pulse depression was increased in slices from dark-reared animals. This increase was mimicked by GABAAR blockade in slices from normally reared animals, suggesting that experience-dependent maintenance of GABAAR function prevents an increase in probability of neurotransmitter release. GABABR-mediated short-term depression in response to strong stimulation (such as occurs during vision) was reduced in slices from dark-reared animals. This change was mimicked in slices from normal animals by reducing GABA release. These results are consistent with the hypothesis that early visual experience maintains GABAergic inhibition and prevents later deprivation-induced alterations of short-term depression in SC. Identifying how plasticity is restricted in mature circuits could guide therapies to enhance recovery of function in adults.
Abstract. During everyday experiences, people sometimes close their eyes to better understand spoken words, to listen to music, or when touching textures and objects. A plausible explanation for this observation is that a reversible loss of vision changes the perceptual function of the remaining non-deprived sensory modalities. Within this work, we discuss general aspects of the effects of visual deprivation on the perceptual performance of the non-deprived sensory modalities with a focus on the time dependency of these modifications. In light of ambiguous findings concerning the effects of short-term visual deprivation and because recent literature provides evidence that the act of blindfolding can change the function of the non-deprived senses within seconds, we performed additional psychophysiological and functional magnetic resonance imaging (fMRI) analysis to provide new insight into this matter. Eye closure for several seconds led to a substantial impact on tactile perception probably caused by an unmasking of preformed neuronal pathways.