AUTHOR=Bertini Caterina , Pietrelli Mattia , Braghittoni Davide , Làdavas Elisabetta 

TITLE=Pulvinar Lesions Disrupt Fear-Related Implicit Visual Processing in Hemianopic Patients

JOURNAL=Frontiers in Psychology

VOLUME=Volume 9 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2018.02329

DOI=10.3389/fpsyg.2018.02329

ISSN=1664-1078

ABSTRACT=The  processing of emotional stimuli in the absence of awareness has been widely investigated in patients with lesions to the primary visual pathway since the classical studies on affective blindsight. In addition, recent evidence has shown that in hemianopic patients without blindsight only unseen fearful faces can be implicitly processed, inducing enhanced visual encoding (Cecere, Bertini, Maier, & Làdavas, 2014) and response facilitation (Bertini, Cecere, & Làdavas, 2013, 2017) to stimuli presented in their intact field. This fear-specific facilitation has been suggested to be mediated by activity in the spared visual subcortical pathway, comprising the superior colliculus (SC), the pulvinar and the amygdala. This suggests that the pulvinar might represent a critical relay structure, conveying threat-related visual information through the subcortical visual circuit. To test this hypothesis, hemianopic patients, with or without pulvinar lesions, performed a go/no-go task in which they were asked to discriminate simple visual stimuli (Gabor patches) presented in their intact field, while fearful, happy and neutral faces were concurrently presented in their blind field. In line with previous evidence, hemianopic patients without pulvinar lesions showed response facilitation to stimuli presented in the intact field, during the concurrent presentation of fearful faces in their blind field. In contrast, no facilitatory effect was found in hemianopic patients with lesions of the pulvinar. These findings reveal that pulvinar lesions disrupt the implicit visual processing of fearful stimuli in hemianopic patients, therefore suggesting a pivotal role of this structure in relaying fear-related visual information from the SC to the amygdala.