Attention in visually typical and amblyopic children

Abstract

Amblyopia is a cortical visual disorder caused by unequal visual input to the brain from the two eyes during development. Amblyopes show reduced visual acuity and contrast sensitivity and abnormal binocularity, as well as more "global" perceptual losses, such as figure-ground segregation and global form integration. Currently, there is no consensus on the neural basis for these higher-order perceptual losses. One contributing factor could be that amblyopes have deficiencies in attention, such that the attentional processes that control the selection of information favor the better eye. Previous studies in amblyopic adults are conflicting as to whether attentional deficits exist. However, studies where intact attentional ability has been shown to exist were conducted in adults; it is possible that it was acquired through experience. To test this hypothesis, we studied attentional processing in amblyopic children. We examined covert endogenous attention using a classical spatial cueing paradigm in amblyopic and visually typical 5-to 10-year old children. We found that all children, like adults, independently of visual condition, benefited from attentional cueing: They performed significantly better on trials with an informative (valid) cue than with the uninformative (neutral) cue. Response latencies were also significantly shorter for the valid cue condition. No statistically significant difference was found between the performance of the amblyopic and the visually typical children or between dominant and nondominant eyes of all children. The results showed that covert spatial attention is intact in amblyopic and visually typical children and is therefore not likely to account for higher-order perceptual losses in amblyopic children.

Neural correlates of visual spatial selective attention are altered at early and late processing stages in human amblyopia

“…This was observed in the entire sample regardless of the eye tested. That is in line with Sharma et al, (2000), Roberts et al, (2016) and Ramesh et al, (2020), who reported more accurate responses to target Gabor patches on the validly cued side and suggest that both amblyopic observers and neurotypical observers profit from the auditory cue. Interestingly, neural correlates support those findings: ERPs to validly cued standard Gabor patches occurred earlier over contralateral compared to ipsilateral scalp sites in all participants.…”

“…Nevertheless, they also found that cueing the attention to the target location in amblyopic observers improved their performance, while cueing attention to an invalid location reduced performance. Indeed, both adults and 5-10 years old children with amblyopia benefit from the cue presentation in a similar manner to neurotypical observers by showing enhanced performance in validly cued trials compared to invalidly cued trials, and reduced performance with invalid cues (Ramesh et al, 2020;Roberts et al, 2016;Sharma et al, 2000), leading to the conclusion that covert spatial selective attention is intact in individuals with amblyopia across different age groups.…”

Exogenous attention generalizes location transfer of perceptual learning in adults with amblyopia

“…Critically, there was a significant 3-way interaction among Session, Diagonal and Group [F(1,12)=5.94, p=.031, η 2 G =.037]: At the trained diagonal, both groups showed higher performance at post-test than pre-test [Neutral group: M=1.83±.13 vs. M=1.10±. 18 (1,6)=21.6, p=.004, η 2 G =.39; both main effect of Diagonal and interaction F<1]. Consistent with these findings, the complementary 2-way (Diagonal X Group) mixed ANOVA of normalized proportion change revealed that only the 2-way interaction between Diagonal (trained, untrained) and Group (Neutral, Attention) was significant [F(1,12)=9.46, p=.010, η 2 G =.13].…”

“…More recently, it has been hypothesized that increased fixation instability (particularly for strabismics) leads to higher rates of microsaccades, or fixational eye movements <1°, which results in an amblyopic deficit in selective attention [54]. However, there is controversy as to whether amblyopes reliably generate higher rates of microsaccades (see Discussion of [18]). Further, there is not a direct or causal correspondence between eye movements at any scale and voluntary or involuntary attention (review [71]); neurotypical (review [25]) and amblyopic (e.g.…”

“…Given that spatial attention cues typically improve behavioral performance in amblyopia [16][17][18]32], and that attention helps overcome VPL location [28][29][30] and feature [30] specificity in neurotypical adults, here we investigated whether and to what extent exogenous attention facilitates VPL and its transfer in adults with amblyopia. There are alternative hypotheses for this open question.…”