Attentional resources and hemispheric functional asymmetry in schizophrenia

Abstract

Inconsistent findings within certain areas of schizophrenia research--processing of verbal and pictorial stimuli, and hemispheric functional asymmetry--suggest the importance of examining the attentional resources associated with the cerebral hemispheres among schizophrenics. A cognitive task battery was developed which assessed the functioning of the left and right hemispheres under varying attentional loads. This battery was administered to paranoid and non-paranoid schizophrenics, and three control groups. Error rate and response latencies were monitored. It was found that the schizophrenics, particularly the non-paranoids, displayed evidence of a generalized decrease in available resources across attentional pools. In addition, response latencies were indicative of a complex interaction involving loads and visual field of stimulus presentation, which differed across schizophrenic subtypes. These lateralized effects among the schizophrenics did not interact with the differential sensitivity of the hemispheres to stimulus characteristics.

Stochastic dynamics of stimulus encoding in schizophrenia: Theory, testing, and application

“…There were significant group differences in performance accuracy (see Table 1), but not so as to compromise latency-rendered inferences (see, e.g., Pachella (1974); cf. Townsend and Wenger (2004); also, in the present instance, ANOVA's on all latencies differed trivially from those on correct responses only; see George and Neufeld (1987)). …”

“…The paradigm was designed initially to examine schizophrenia deviations in the following functional brain asymmetry (George & Neufeld, 1987): a left ''hemifield'' (right visual field) advantage for processing verbal stimuli, and a right hemifield (left visual field) advantage for processing pictorial stimuli (see, e.g., Moscovitch and Klein (1980) and Sergent (1982)). Principal experimental manipulations involved composition of presented stimuli (fourletter words or pictures of faces), and visual field of presentation.…”

“…Briefly, they differentially tapped hemispheric resources considered to be particularized to the stimulus type for the given trial (left hemisphere, in the case of words, and right hemisphere in the case of faces). Justification for their inclusion, and associated procedures, are detailed in George and Neufeld (1987) and Neufeld, Vollick et al (2007). Note that the auxiliary procedures did not detract from the validity of data for the present modeling purposes, and their presence is built into the model predictions, below.…”

A formal analysis of stressor and stress‐proneness effects on simple information processing

“…The present instrumentation, was not designed expressly to tap differential processing of stimulation in the alternate hemifields (cf. George & Neufeld, 1987). Nevertheless, lateralized processing efficiency, without highly constrained manipulations, is far from out of the question (e.g.…”

Addressing very short stimulus encoding times in modeling schizophrenia cognitive deficit

“…At this point an adequate method has not been determined (although see Donders (1969) and Townsend and Wenger (2004) for a discussion). It should be noted that an attempt by the present author to obtain encoding times for the George and Neufeld (1987) data by subtracting the estimates of E(Y) and E(W)…”