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

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.

[1]  D. Wilkin,et al.  Neuron , 2001, Brain Research.

[2]  A. Cowey,et al.  Blindsight in man and monkey. , 1997, Brain : a journal of neurology.

[3]  S. Hillyard,et al.  Identification of early visual evoked potential generators by retinotopic and topographic analyses , 1994 .

[4]  S. Hillyard,et al.  Allocation of visual attention to spatial locations: Tradeoff functions for event-related brain potentials and detection performance , 1990, Perception & psychophysics.

[5]  A. Marcel,et al.  Blindsight and shape perception: deficit of visual consciousness or of visual function? , 1998, Brain : a journal of neurology.

[6]  L Weiskrantz,et al.  Learning from the pupil: a spatial visual channel in the absence of V1 in monkey and human. , 1998, Brain : a journal of neurology.

[7]  L. Weiskrantz,et al.  Awareness and confidence ratings in motion perception without geniculo-striate projection , 1998, Behavioural Brain Research.

[8]  A. Cowey,et al.  Wavelength discrimination in blindsight. , 1992, Brain : a journal of neurology.

[9]  C. Kennard,et al.  Residual colour vision in a human hemianope: spectral responses and colour discrimination , 1994, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[10]  L. Weiskrantz Blindsight : a case study and implications , 1986 .

[11]  Alan Cowey,et al.  Wavelength sensitivity in blindsight , 1989, Nature.

[12]  P. Ekman,et al.  Measuring facial movement , 1976 .

[13]  G. Mangun Neural mechanisms of visual selective attention. , 1995, Psychophysiology.

[14]  J. Vroomen,et al.  Covert Processing of Faces in Prosopagnosia Is Restricted to Facial Expressions: Evidence from Cross-Modal Bias , 2000, Brain and Cognition.

[15]  J. Winn,et al.  Brain , 1878, The Lancet.