Noninvasive transcranial brain stimulation for the study of perception and attention

Humans are highly specialized in perceiving and interpreting sensory information. This chapter explores how noninvasive brain stimulation (NIBS) has advanced our understanding of perception and attention, with a focus on visual perception. In the first part, we introduce visual and attentional networks, and their links to visual performance and awareness. In the second part, we examine how stimulating visual areas can evoke percepts without external stimuli (e.g., phosphenes) or alter perception of external visual stimuli. In the third part, we discuss top-down influences from fronto-parietal regions on detection and categorization, including attentional modulation through cortical oscillations. The fourth part is devoted to the conscious interpretation of bistable stimuli as a case of higher-level visual perception. Finally, in the fifth part, we review how NIBS informs our understanding and treatment of visuospatial neglect—a condition affecting awareness after attentional network damage.