The Role of Early Visual Experience in Cross-Signal Dependency Detection

Temporal co-occurrence of two sensory signals is a powerful indicator of their potential association. Detection of such coincidences is believed to be a key contributor to perceptual organization and a primary objective of cortical computations. Here, we investigate whether the development of this ability requires early sensory experience. We examined the performance of early-blind children who surgically gained sight as adolescents. Our data revealed three key results. First, we found that while not fully reaching the level of normally sighted controls, late-sighted patients examined several years after surgery were able to robustly detect signal dependencies with markedly above-chance accuracy at all but the weakest strengths tested. Second, for both groups, performance levels were comparable for intra- and inter-modal stimuli, revealing significant plasticity for establishing cross-modal linkages late in childhood. Finally, comparison with a separate group of late-sighted patients tracked longitudinally from preoperative to one-month postoperative status suggests that this ability may follow a protracted developmental time course after sight surgery. These results help characterize the development of a foundational process for detecting relationships between environmental entities and point to the resilience of acquiring this important skill to early-onset, prolonged visual deprivation. SUMMARY: We tested the ability of congenitally blind children who gained sight late in childhood to detect repeated temporal co-occurrence of sensory signals. We found that while not reaching the full normally sighted level, late-sighted patients are able to detect signal dependencies with markedly above-chance accuracy. This ability may follow a protracted developmental time course after sight-restoring surgery. The availability of neural plasticity into late childhood has important implications for the rehabilitation prospects of children with congenital blindness.