Effects of antipsychotics on cognitive functions: an ERP study in healthy controls

Abstract

IntroductionClinical studies on cognitive effects of second generation antipsychotics produced disappointing findings probably due to the heterogeneity of the clinical populations under investigation, as well as to poor sensitivity of neurocognitive indices. Event-Related Potentials (ERPs) provide a functional measure of electrical brain activity time-locked to discrete stages of information processing. They have been widely used as putative biological markers of cognitive abnormalities in schizophrenia and represent useful indices in the investigation of the cognitive effects of psychotropic drugs.ObjectivesThe present study investigated the effect of risperidone, haloperidol and placebo on N1 and P3 in male healthy subjects.MethodsERPs were recorded during a three-tone oddball task in which target, standard and rare-nontarget tones were randomly presented. Subjects had to press a button when hearing a target tone. Amplitude and topography of the ERP component maps at peak latencies were compared across conditions. If a significant drug effect was obtained, changes in the cortical sources of the corresponding ERP component were analyzed using Low-Resolution Electromagnetic Tomography (LORETA).ResultsThe amplitude of N1 for attended stimuli and of P3 for rare-nontargets (P3a) was significantly increased only by risperidone. No significant change was observed in overall topographic features and in LORETA cortical sources of the same components. No significant drug effect was demonstrated for the latency of all the investigated components and for P3b amplitude.ConclusionsOur findings suggest that risperidone has a favorable effect on early attention processes and automatic attention allocation.

Event-related brain potentials to emotional images and gonadal steroid hormone levels in patients with schizophrenia and paired controls

“…The effects of different molecules of antipsychotic drugs on the emotional experience are not very clear, although evidence suggests that such effects are minor ( Berenbaum and Oltmanns, 1992 ; Kring and Neale, 1996 ). However, more recently, several studies were able to demonstrate interactions between certain types of antipsychotic medication and cognitive functions ( Davidson et al, 2009 ; Marston et al, 2009 ; Mucci et al, 2011 ), a situation which could produce effects on emotions. Given that we are investigating hormonal differences, it would be more relevant to divide each group of women, according to either luteal or follicular phase of the menstrual cycle at the time of EEG/ERP recording.…”