INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY ELSEVIER International Journal of Psychophysiology 34 (1999) 341-348 www.elsevier.com/locate/physcho Learned control of slow potential interhemispheric asymmetry in schizophrenia John Gruzelier *, Elinor Hardman, Jennifer Wild, Rashid Zaman Department of Behavioural and Cognitive Sciences, Division of Neuroscience and Psychological Medicine, Imperial College School of Medicine at Charing Cross Hospital, University of London, London, UK Received 7 July 1998; received in revisedform 23 October 1998; accepted 5 January 1999 Abstract We report on the feasibility of teaching 16 (DSM-IV) schizophrenic patients, subdivided by syndrome, self-regu- lation of interhemispheric asymmetry having demonstrated efficient learning of interhemispheric control in normal subjects. Reversal of asymmetry may be important to treatment and recovery in schizophrenia for following improvement on neuroleptic drugs functional hemispheric asymmetries have reversed, with directions of reversal and pre-existing asymmetry dependent on syndrome. Asymmetry reversal in animals, manifested by spatial turning tendencies, has been used as a marker of neuroleptic action and involves striatal dopamine under reciprocal hemispheric control. We gave as feedback the left-right asymmetry in slow potential negativity recorded from the sensory motor strip (C3,4). Feedback took the form of a rocket on a screen which rose or fell with leftward or rightward shifts in negativity. Patients were able to learn control (P < 0.01). In those patients with lesser ability this was due to inability to sustain concentration throughout the session rather than slow initial learning. Active syndrome patients were better able to shift negativity rightward and withdrawn patients leftward, directions associated with drug reversal of functional asymmetry and symptom recovery for each syndrome. Accordingly our demonstration that many symptomatic schizophrenic patients are capable of learning control opens the door to electrocortical operant conditioning training in schizophrenia with therapeutic regimens. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Schizophrenia; EEG; Operant conditioning; Slow potentials; Laterality; Syndrome * Corresponding author, Department of Behavioural and Cognitive Sciences, Imperial College Schoolof Medicine, St Dunstan's Road, London W6 8RF. Tel.: +44-181-846-7386; fax: +44-181-846-1670. E-mail address:j.gruzelier@ic.ac.uk (1. Gruzelier) 0167-8760/99/$ - see front matter © 1999 Elsevier Science B.Y. All rights reserved. PH: SOl 67- 8760 (99)00091-4