Perceptual Difficulty Regulates Attentional Gain Modulations in Human Visual Cortex

Abstract

Perceptual difficulty is sometimes used to manipulate selective attention. However, these two factors are logically distinct. Selective attention is defined by priority given to specific stimuli based on their behavioral relevance, whereas perceptual difficulty is often determined by perceptual demands required to discriminate relevant stimuli. That said, both perceptual difficulty and selective attention are thought to modulate the gain of neural responses in early sensory areas. Previous studies found that selectively attending to a stimulus or increasing perceptual difficulty enhanced the gain of neurons in visual cortex. However, some other studies suggest that perceptual difficulty can have either a null or even reversed effect on gain modulations in visual cortex. According to Yerkes-Dodson's Law, it is possible that this discrepancy arises due to an interaction between perceptual difficulty and attentional gain modulations yielding a non-linear inverted-U function. Here, we used EEG to measure modulations in the visual cortex of male and female human participants performing an attention-cueing task where we systematically manipulated perceptual difficulty across blocks of trials. The behavioral and neural data implicate a non-linear inverted-U relationship between selective attention and perceptual difficulty: a focused-attention cue led to larger response gain in both neural and behavioral data at intermediate difficulty levels compared to when the task was more or less difficult. Moreover, difficulty-related changes in attentional gain positively correlated with those predicted by quantitative modeling of the behavioral data. These findings suggest that perceptual difficulty mediates attention-related changes in perceptual performance via selective neural modulations in human visual cortex.SIGNIFICANCE STATEMENT:Both perceptual difficulty and selective attention are thought to influence perceptual performance by modulating response gain in early sensory areas. That said, less is known about how selective attention interacts with perceptual difficulty. Here, we measured neural gain modulations in the visual cortex of human participants performing an attention-cueing task where perceptual difficulty was systematically manipulated. Consistent with Yerkes-Dodson's Law, our behavioral and neural data implicate a non-linear inverted-U relationship between selective attention and perceptual difficulty. These results suggest that perceptual difficulty mediates attention-related changes in perceptual performance via selective neural modulations in visual cortex, extending our understanding of the attentional operation under different levels of perceptual demands.

Age-related differences in electrophysiological correlates of visuospatial reorientation

“…Moreover, the fact that older adults presented a decreased P1 amplitude suggests that they may have impairments in the early categorization process of visual stimuli which are exacerbated by the reorientation task. Then, when faced with increased perceptual difficulty older adults required more time to allocate greater attentional resources to the harder perceptual task (Sawetsuttipan et al, 2023). These findings align with the two leading cognitive aging hypotheses which posit that aging is associated with an inhibitory deficit ( i.e., decreased P1 amplitude) and the processing speed hypothesis, ( i.e ., increased P1 latency) when the perceptual difficulty of the task is increased (Finnigan et al, 2011; Gazzaley et al, 2008).…”