OADES, R. D., MÜLLER, B. W., BENDER, S., & SARTORY, G. (2001) Neuropsychological indicators of heteromodal cortex (dys)function relevant to conditioned blocking measures of attention in schizophrenia. Cognitive Neuropsychiatry, 6, 41-61. - ( request a copy)

In accord with our understanding of journal policy, we present the pre-publication text (view). The original publication (cited above: ISSN 1354-6805, Online ISSN: 1464-0619) is available at http://www.ingentaconnect.com/content/psych/pcnp/2001/00000006/00000001/art00004

Background.
Learning a predictive relationship between two events can block learning about an added event (conditioned blocking, CB). Patients with nonparanoid schizophrenia can show reduced CB and learn about the similar consequences of the added event. What parts of the brain are involved in the functions required in learning the CB task and actually showing 'blocking' - a part of normal selective attention processes? As a first approximation, we ask if neuropsychological test performance sensitive to specific cortical regions is associated with these two functions.

Methods.
This study reports on the relationship of associative learning and CB measures of attention obtained with a visuospatial maze-like task to signs of heteromodal cortex function provided by performance on a battery of 10 neuropsychological tasks. These tasks were sensitive to frontal, parietal and temporal lobe function of the left and right hemisphere. Acquisition criteria for the task were achieved by 62 patients with schizophrenia and 62 matched controls but not by 39 other people with schizophrenia.

Results.
First right-hemisphere, visuo-spatial abilities were generally associated with faster task-learning (e.g. visual reproduction, immediate and delayed, picture-completion), and patients that could not learn the task were poorer on tests emphasising set-switching and problem-solving abilities associated with left frontal lobe function (e.g. trail-making, block-design).
Second CB expression depended on Stroop- and Mooney-faces-task performance that are reported to require cingulate and parietal lobe function.

Conclusions.
As would be predicted right hemisphere function was implicated in performing a visuospatial learning task. The additional CB requirement incurred additional anterior cingulate and right parietal involvement. Functionally this probably reflected effortful attentional processes, and illustrates the problems of patients with schizophrenia in switching between automatic and controlled processing strategies. The results are astonishingly consistent with imaging studies implicating brain regions such as the cingulate and intra-parietal sulcus in attention (Mesulam, 1999).

[This report was conceived as the second of 5 reports on Project 1 (blocking), see also 1) Schizophr. Res., (associations with symptoms and onset) 2) Behav. Pharmacol. (associations with dopamine D2 receptor occupancy): (2 other reports still in prep.).
Our first blocking study in schizophrenia: a) 1996 Dev.Neuropsychol., b) 1996 J.Psychiat. Res. c) 1992 Acta Paedopsychiat. ]
The effect on CB of DA-depleting lesions in the Frontal cortex, Septum and VTA in rats was reported in Oades et al., 1987.