Non-conscious recognition of affect in the absence of striate cortex

Abstract

Functional neuroimaging experiments have shown that recognition of emotional expressions does not depend on awareness of visual stimuli and that unseen fear stimuli can activate the amygdala via a colliculopulvinar pathway. Perception of emotional expressions in the absence of awareness in normal subjects has some similarities with the unconscious recognition of visual stimuli which is well documented in patients with striate cortex lesions (blindsight). Presumably in these patients residual vision engages alternative extra-striate routes such as the superior colliculus and pulvinar. Against this background, we conjectured that a blindsight subject (GY) might recognize facial expressions presented in his blind field. The present study now provides direct evidence for this claim.

From affective blindsight to emotional consciousness

“…As in the original study, the patients, prompted by consciously perceived auditory stimuli, are forced to guess and to press different buttons for different emotions that may be displayed (de Gelder et al, 1999;Pegna et al, 2005;Van den Stock et al, 2011). Most commonly, direct behavioral measures rely on response accuracy and latency.…”

“…Thus, it has been proposed, and later on verified with different neuroimaging methods, that considerable post-lesion and experience-dependent plasticity has taken place in GY's brain (Bridge et al, 2008;Tamietto et al, 2012). Although we will discuss the neural underpinnings of affective blindsight in a dedicated section below, it has become increasingly clear that affective blindsight is not such a rare phenomenon, for it has been reported in more than 20 different patients studied by at least five independent research teams in several different countries (Anders et al, 2004(Anders et al, , 2009Bertini et al, 2013;Cecere et al, 2014;de Gelder & Hadjikhani, 2006;de Gelder et al, 1999de Gelder et al, , 2002de Gelder et al, , 2005de Gelder et al, , 2014Hamm et al, 2003;Heywood & Kentridge, 2000;Morris et al, 2001;Pegna et al, 2005;Rossion et al, 2000;Tamietto & de Gelder, 2008;Tamietto et al, 2009Tamietto et al, , 2012Van den Stock et al, 2011). These patients suffered different lesions to the visual cortex at different ages, but for the large majority in adulthood, and two of them had bilateral cortical blindness.…”

“…The phenomenon, referred to as ''affective blindsight'', denotes the uncanny ability of such patients to respond correctly, or above chance level, to emotionally salient visual stimuli presented to their blind fields (Anders et al, 2004(Anders et al, , 2009Bertini, Cecere, & Ladavas, 2013;Cecere, Bertini, Maier, & Ladavas, 2014;de Gelder & Hadjikhani, 2006;de Gelder, Morris, & Dolan, 2005;de Gelder, Pourtois, van Raamsdonk, Vroomen, & Weiskrantz, 2001; de Gelder, Pourtois, & http://dx.doi.org/10.1016/j.concog.2015.05.007 1053-8100/Ó 2015 Elsevier Inc. All rights reserved. Weiskrantz, 2002;de Gelder, Tamietto, Pegna, & Van den Stock, 2014;de Gelder, Vroomen, Pourtois, & Weiskrantz, 1999;Hamm et al, 2003;Heywood & Kentridge, 2000;Morris, DeGelder, Weiskrantz, & Dolan, 2001;Pegna, Khateb, Lazeyras, & Seghier, 2005;Rossion, de Gelder, Pourtois, Guerit, & Weiskrantz, 2000;Tamietto & de Gelder, 2008;Tamietto, Pullens, de Gelder, Weiskrantz, & Goebel, 2012;Tamietto et al, 2009;Van den Stock et al, 2011). As is the case for the original phenomenon of ''blindsight'' (Pöppel, Held, & Frost, 1973;Weiskrantz, Warrington, Sanders, & Marshall, 1974), the ''blind'' component in affective blindsight refers to the patients' statement of not seeing or consciously perceiving the emotional stimuli, while the ''sight'' component reflects their residual ability to respond, discriminate or display spontaneous expressive and physiological responses that are appropriate to the specific emotional content of the visual signals they are presented with.…”

Faces, Bodies, Social Vision as Agent Vision, and Social Consciousness

“…New experiments on affective blindsight investigated possible online interaction between the aware and the unaware modes of emotional processing, as well as the influence exerted by unseen emotions over ongoing recognition of other consciously perceived stimuli(de Gelder, Morris, & Dolan, 2005;de Gelder, Pourtois, van Raamsdonk, Vroomen, & Weiskrantz, 2001;de Gelder, Pourtois, & Weiskrantz, 2002;Tamietto, Weiskrantz, Geminiani, & de Gelder, 2007). This series of studies took advantage of indirect methods of testing which, as compared to direct "guessing" methods, cannot be influenced by deliberate response strategies used by the patient.…”

Visual stimuli modulate frontal oscillatory rhythms in a cortically blind patient: Evidence for top-down visual processing

“…In an initial study, de Gelder et al (1999) showed that a patient was able to guess above chance level the expression of emotional faces, even though he was unaware of the presence of the stimulus. Another study on a patient (TN) with bilateral V1 destruction (Pegna et al, 2005) showed that emotionally expressive faces elicited brain responses, notably in the right amygdala.…”