Search

Burgmans et al. (2009) stated that the prevalence of cortical gray matter atrophy may be overestimated in the healthy aging brain, because the inclusion of participants with preclinical cognitive pathology might have been responsible for the age effects found in previous studies. Fjell et al. (2010) and Raz and Lindenberger (2010) verified this statement by reanalyzing previously published data. They both argue that it is unlikely that preclinical cognitive pathology explains cortical gray matter atrophy in healthy aging. Burgmans et al. (2010) respond to these commentaries. © 2010 American Psychological Association.

The aim of this study was to identify whether specific deficits in cognitive processing are present in schizophrenia and whether these ave related to the volume of temporal and limbic structures. Twenty-seven schizophrenic outpatients were compared with 19 matched control subjects. Compared with control subjects, patients performed complex tasks disproportionately worse than they performed simple tasks, No group differences were found with regard to temporal and limbic volume. Volume of the parahippocampal gyrus was correlate with cognitive performance. The findings are interpreted as evidence for a dysfunction in the maintenance of task-relevant information and the inhibition of irrelevant information.

Road traffic accidents are largely determined by human errors in information processing and attention. Attentional functions constitute a vulnerable link in the human information processing chain. Three distinct attentional brain mechanisms are described that are considered to be involved in the supply of nervous energy for information processing. Arousal, phasic physiological responses to novel stimuli; Activation, tonic physiological readiness to respond; and Effort, the voluntarily exerted coordination between arousal and activation. These energy supply systems are mainly driven by noradrenergic, dopaminergic and cholinergic neurotransmission, respectively. Furthermore, they are affected by a behavioural inhibition system controlled by serotonin. The histamine neurotransmitter system is also associated with behavioural activation, whereas the neurotransmitter GABA has an inhibitory influence on the noradrenergic, dopaminergic and cholinergic systems. It is argued that the effects of drugs on driving can be predicted in terms of their effects on these neurochemical systems. Drugs that decrease noradrenaline-, acetylcholine-, dopamine- and histamine-neurotransmitter turn-over impair different facets of attention. GABAergic drugs are sedative, while serotonergic drugs seem to influence attention in a more subtle manner. Any pharmacological intervention on one or more of these systems via medicinal or other psychoactive drugs, can alter, and often impair, driving performance. The assessment of behavioural, psychophysiological and pharmacological markers of the attentional systems during driving performance may provide clues for the answer to the question how, rather than if, drugs have an influence on driving performance.