Neuroplasticity in adult human visual cortex

TL;DR

This paper reviews evidence that the adult human visual cortex retains significant plasticity, including homeostatic plasticity, which can be harnessed for vision restoration therapies in conditions like amblyopia and retinal dystrophies.

Contribution

It synthesizes recent findings demonstrating adult visual cortex plasticity and its potential for improving vision through targeted therapies and artificial stimulation.

Findings

Adult visual cortex exhibits homeostatic plasticity.

Plasticity can be exploited for amblyopia recovery.

Artificial stimulation activates visual cortex in late-blind patients.

Abstract

Between 1 to 5 out of 100 people worldwide has never experienced normotypic vision due to a condition called amblyopia, and about 1 out of 4000 suffer from inherited retinal dystrophies that progressively lead them to blindness. While a wide range of technologies and therapies are being developed to restore vision, a fundamental question still remains unanswered: would the adult visual brain retain a sufficient plastic potential to learn how to see after a prolonged period of abnormal visual experience? In this review we summarize studies showing that the visual brain of sighted adults retains a type of developmental plasticity, called homeostatic plasticity, and this property has been recently exploited successfully for adult amblyopia recover. Next, we discuss how the brain circuits reorganizes when visual stimulation is partially restored by means of a bionic eye in late blinds with Retinitis Pigmentosa. The primary visual cortex in these patients slowly became activated by the artificial visual stimulation, indicating that sight restoration therapies can rely on a considerable degree of spared plasticity in adulthood.