Activation and maintenance of peripheral semantic features of unambiguous words after right hemisphere brain damage in adults

Abstract

Background-The right cerebral hemisphere (RH) sustains activation of subordinate, secondary, less common, and/or distantly related meanings of words. Much of the pertinent data come from studies of homonyms, but some evidence also suggests that the RH has a unique maintenance function in relation to unambiguous nouns. In a divided visual field priming study, Atchley, Burgess, and Keeney (1999) reported that only left visual field/RH presentation yielded evidence of continuing activation of peripheral semantic features that were incompatible with the most common image or representation of their corresponding nouns (e.g., rotten for "apple"). Activation for weakly related features that were compatible with the dominant representation (e.g., crunchy) was sustained over time regardless of the visual field/hemisphere of initial stimulus input. Several studies report that unilateral right hemisphere brain damage (RHD) in adults affects the RH's meaning maintenance function, but this work also has centred on homonyms, and/or more recently metonymic and metaphoric polysemous words.

Contextual Constraint Treatment for coarse coding deficit in adults with right hemisphere brain damage: Generalisation to narrative discourse comprehension

“…It has been proposed that adults with RHD have a specific deficit in processing metaphors and other non-literal language (e.g., Klepousniotou & Baum, 2005; Lundgren, Brownell, Cayer-Meade, Milione & Kearns, 2011). However, in line with several theories on the continuity of literal and nonliteral language processing (Coulson & Van Petten, 2002; Grady, Oakley & Coulson, 1999; Pynte, Besson, Robichon & Poli, 1996), it is also possible that difficulties with the activation and maintenance of metaphoric meanings reflect a special case of coarse coding in which the non-literal meanings reflect subordinate or distant meanings (Tompkins, Fassbinder et al, 2008; Tompkins, Scharp et al, 2008). In this case, improving the coarse coding process should facilitate access to metaphoric meanings, and improve interpretation of metaphors and perhaps other non-literal language forms.…”

“…Additionally, most studies focus on generation of multiple meanings of homonyms (e.g., Burgess & Simpson, 1988; Klepousniotou & Baum, 2005). Tompkins and colleagues (Tompkins, Fassbinder, Scharp & Meigh, 2008; Tompkins, Scharp, Meigh & Fassbinder, 2008) conducted two direct studies of coarse coding in adults with RHD focusing on activation of distantly-related, or peripheral, features of unambiguous words. To maximize the likelihood that coarse coding processes were being tapped, extensive piloting was conducted to verify that the features were only peripherally related.…”

Hemispheric differences in the processing of contextual information during language comprehension

“…A large amount of evidence in the literature (see Tompkins, Fassbinder, Scharp, & Meigh, 2008, for a review) supports this suggestion that the processing mechanisms used by the RH maintain activation of the contextual information, particularly peripheral features or subordinate meanings, whereas the LH does not. For example, Faust, Barak, and Chiarello (2006) investigated whether the two hemispheres maintain activation of script meaning (i.e., context) across neutral and unrelated information.…”

“…Although this sort of finding has been observed in a number of studies investigating particular capacities such as inference generation (Beeman et al, 2000;Mason & Just, 2004) and information maintenance (Tompkins et al, 2008), few behavioural studies have, until recently, demonstrated this advantage for extracting meaning from short contextual sentences. This finding therefore adds to the growing body of evidence that a special contribution of the RH to language tasks is its ability to extract, build and maintain access to a contextual base.…”

“…Their findings suggested that although the RH kept several words simultaneously activated, LH activation of word meanings related to earlier scripts quickly declined once additional sentences were added. Similarly, Tompkins et al (2008) found that sustained activation of peripheral semantic features of nouns was less in individuals with right hemisphere damage (RHD) that were poor comprehenders than those that were good comprehenders. These findings provide some support for the notion that differences in hemispheric processing mechanisms might be reflected in their respective abilities to maintain activation of contextual information and are thus consistent with Federmeier's (2007) framework.…”