Task evoked EEG reveals neural processing differences in aphantasia.

Aphantasia, the inability to generate voluntary visual images, affects an estimated 3-4% of the population and provides a valuable model for examining how the brain supports cognition without imagery. Functional MRI studies have reported reduced coordination between visual and higher-order association areas involved in imagery control. However, the temporal characteristics of these neural differences remain unclear, as electroencephalographic (EEG) evidence limited to single-case studies. Here we present the first group-level EEG investigation of aphantasia, comparing 62 individuals with the condition to 59 controls during rest and tasks probing attention and working memory. In the oddball task, participants with aphantasia demonstrated smaller P300 amplitudes, an EEG index of attentional allocation and the updating of task-relevant information into working memory. Given the absence of behavioural differences between groups, we propose this result reflects reduced engagement of imagery-related processes during this task rather than diminished cognitive function. Under high working-memory load in the n-back task, individuals with aphantasia showed lower delta power-brain activity linked to regulating sensory input and maintaining internal representations. Notably, delta power was also associated with imagery vividness (VVIQ), potentially indicating greater engagement of these sensory-regulating processes in individuals with stronger imagery. Together, these findings suggest that individuals with aphantasia may rely more on non-visual strategies for information maintenance, thereby reducing sensory interference and demands on inhibitory control. This study provides the first EEG evidence that people with aphantasia have distinct-but effective-neural dynamics that support cognition without visual imagery.