Differential lateralization of memory discrimination and response bias in temporal lobe epilepsy patients

Abstract

Recognition memory for words and designs was assessed in epilepsy patients who underwent unilateral anterior temporal lobectomy. Memory was assessed during the intracarotid amobarbital test (IAT) performed prior to surgery and also following surgery. Memory discrimination and response bias lateralized differently. Memory discrimination, or memory accuracy, lateralized as a function of the type of material used in memory testing. Left temporal lobe lesions resulted in more impaired discrimination of verbal materials; right temporal lobe lesions resulted in more impaired discrimination of visuospatial materials. Response bias, the decision rule adopted in situations of uncertainty, was more liberal following left temporal lobe lesions for both verbal and visuospatial materials. Findings suggest that the two cerebral hemispheres are differentially specialized for encoding different types of information in long term memory, and that this impacts on decision strategies in situations of memory uncertainty. (JINS, 1998, 4, 502-511.)

Dissociating Prelexical and Postlexical Processing of Affective Information in the Two Hemispheres: Effects of the Stimulus Presentation Format

“…Although some studies on brain lateralization are available in which signal detection theory or variants thereof have been applied to the data (e.g., Chiarello, Nuding, & Pollock, 1988;Chiarello, MacMahon, & Chaefer, 1989;Funnell, Corballis, & Gazzaniga, 1999;Glosser, Deutsch, Cole, Corwin, & Saykin, 1998;Madden, Nebes, & Berg, 1981), these methods have never before been used to dissociate semantic processing at different perceptual stages in the two hemispheres. If we can demonstrate such dissociation, we might help to establish a paradigm for disentangling hemispheric preferences (bias) from hemispheric skills (accuracy).…”

The development of categorical and coordinate spatial relations

“…In addition, the RH showed a smaller response bias than the LH. Laterality effects for response bias have been reported before and retraced to the early organization of the visual system (Glosser et al, 1998). It should be acknowledged that Glosser et al (1998) for a different task obtained slightly different hemispheric bias trends.…”

“…Sensitivity (also called memory discrimination) refers to the accuracy of memory and represents the degree to which participant is certain in deciding whether or not an item was previously presented. Response bias refers to the strategy that is adopted (that is, saying 'seen before') when participants are uncertain about whether or not they have seen the item before (Glosser et al, 1998;Windmann, Daum, et al, 2002;Windmann, Urbach, et al, 2002). At a behavioral level, these measurements are largely independent of one another (Snodgrass & Corwin, 1988).…”

“…Moreover, since the current change-detection task afforded a signal detection approach, we could establish to what extent cognitive development comprises sensitivity and bias changes. This is specifically interesting since previous research has shown that sensitivity and bias scores on recognition memory tasks are, to a certain extent, correlated with age and hemisphere (Berch & Evans, 1973;Glosser, Deutsch, Cole, Corwin, & Saykin, 1998;Windmann, Daum, & Güntürkün, 2002;Windmann, Urbach, & Kutas, 2002). For example, older children were shown to exhibit greater response biases (Berch & Evans, 1973) and a more liberal response bias was reported for visuo-spatial information encoded by the RH (Glosser et al, 1998).…”

“…Different potential explanations exist for this finding. Affective, contextual or executive factors all contribute to making decisions in uncertain situations and might have a differential impact at different stages of development (Glosser et al, 1998). A plausible explanation, related to the executive factors mentioned, might be sought in the maturity of the frontal regions of the brain during development.…”