Auditory and somatosensory event-related brain potentials in early blind humans

Abstract

Previous event-related potential (ERP) studies have suggested a possible participation of the visual cortex of the blind in auditory processing. In the present study, somatosensory and auditory ERPs of blind and sighted subjects were recorded when subjects were instructed to attend to stimuli of one modality and to ignore those of the other. Both modalities were stimulated with frequent ("standard") and infrequent ("deviant") stimuli, which differed from one another in their spatial locus of origin. In the sighted, deviant stimuli of the attended modality elicited N2 type of deflections (auditory N2b and somatosensory N250) over the lateral scalp areas. In contrast, in the blind, these ERP components were centroposteriorly distributed, suggesting an involvement of posterior brain areas in auditory and somatosensory stimulus discrimination. In addition, the mismatch negativity, elicited by deviant auditory stimuli even when the somatosensory stimuli were attended, was larger in the blind than in the sighted. This appears to indicate enhanced automatic processing of auditory stimulus changes in the blind. Thus, the present data suggest several compensatory changes in both auditory and somatosensory modalities after the onset of early visual deprivation.

Convergence of biological and psychological perspectives on cognitive coordination in schizophrenia

“…A pertinent example is the report of a larger mismatch negativity (MMN) evoked-potential response to deviant auditory stimuli in blind than in sighted humans (Kujala et al 1995). This demonstration of enhanced context sensitivity in the blind stands in stark contrast to the diminished MMN (mismatch negativity) observed in schizophrenics, and also in control samples administered the NMDA-receptor antagonist ketamine (Umbricht et al 2000).…”

Visual Cortex Activity in Early and Late Blind People

“…A likely basis for the extensive visual cortex responses to heard nouns is a general sensitivity to various non-language-related auditory stimuli in early (Kujala et al, 1995a(Kujala et al, ,b, 1997Röder et al, 1996Röder et al, , 2000Röder et al, , 2001Lessard et al, 1998;Liotti et al, 1998;Leclerc et al, 2000;Weeks et al, 2000;Arno et al, 2001) and late blind (Kujala et al, 2000) individuals. A PET study, for example, showed V1 activity in early blind subjects during a soundlocalization task (Weeks et al, 2000).…”

Cerebral organization for language in deaf and hearing subjects: Biological constraints and effects of experience

“…A central issue is how these highly specialized systems arise in human development, the degree to which they are biologically constrained, and the extent to which they depend on and can be modified by input from the environment. Extensive research at many levels of analysis has documented that, within the domain of sensory processing, strong biases constrain development, but many aspects of sensory organization can adapt and reorganize after both increases and decreases in sensory input (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). For example, in humans who have sustained auditory deprivation since birth some aspects of visual processing are unchanged whereas the processing of motion is enhanced and reorganized (10,14,15).…”