Specific Visual Subregions of TPJ Mediate Reorienting of Spatial Attention
Résumé
The temporo-parietal junction (TPJ) has been associated with various cognitive and social functions, and is critical for
attentional reorienting. Attention affects early visual processing. Neuroimaging studies dealing with such processes have
thus far concentrated on striate and extrastriate areas. Here, we investigated whether attention orienting or reorienting
modulate activity in visually driven TPJ subregions. For each observer we identified 3 visually responsive subregions within
TPJ: 2 bilateral (vTPJant and vTPJpost) and 1 right lateralized (vTPJcent). Cortical activity in these subregions was measured
using fMRI while observers performed a 2-alternative forced-choice orientation discrimination task. Covert spatial
endogenous (voluntary) or exogenous (involuntary) attention was manipulated using either a central or a peripheral cue
with task, stimuli and observers constant. Both endogenous and exogenous attention increased activity for invalidly cued
trials in right vTPJpost; only endogenous attention increased activity for invalidly cued trials in left vTPJpost and in right
vTPJcent; and neither type of attention modulated either right or left vTPJant. These results demonstrate that vTPJpost and
vTPJcent mediate the reorientation of covert attention to task relevant stimuli, thus playing a critical role in visual attention.
These findings reveal a differential reorienting cortical response after observers’attention has been oriented to a given
location voluntarily or involuntarily.