Endogenous evoked potentials assessment in depression: a review

Cognitive processing of anorexic patients in recognition tasks: an event-related potentials study

OBJECTIVE

We used event-related potentials (ERPs) to test whether anorexic subjects have difficulties in filtering out irrelevant stimuli in controlled information processing tasks.

METHODS

ERPs from 12 anorexic patients were recorded during recognition of simple and complex body images and simple and complex geometrical shapes.

RESULTS

Anorexic subjects had larger P300 amplitudes for frequent stimuli during body images and simple geometrical shape recognition tasks. Longer P300 latencies were also found in simple geometrical shape recognition tasks, although task complexity had no effect on the P300 latency and amplitude.

DISCUSSION

These results are explained in terms of nonspecific hyperarousal in mental anorexia and relative inability to filter out irrelevant stimuli leading to working memory saturation.

Emotion/cognition-coupling in word recognition memory of depressive patients: an event-related potential study

Depressive patients show deficits in memory functions. However, the underlying mechanisms remain unclear. Experiments with a special emphasis on the link between emotion and cognition appear challenging. The aim of this study is to investigate the influence of the emotional content of words on memory in non-medicated depressive patients (n=11) compared with a control group (n=11) utilizing event-related brain potentials (ERPs). In a continuous word recognition paradigm brain responses to repeated items are characterized by more positive waveforms of ERPs. This recognition effect ('old/new effect') has been shown to be sensitive to parameters relevant for memory processing. For the purpose of this ERP experiment visually presented words were classified into three different categories of emotional content. The ERPs for the correctly detected 'old' (repeated) words showed an increased positivity beginning approximately 250 ms post-stimulus, concurring with a good recognition performance. In addition, old/new effect and behavioral data were sensitive to words' different emotional connotations in the control group. In contrast, the depressive patients performed worse and showed no significant old/new effect. Nevertheless, their recognition performance was also enhanced by the emotional content. Furthermore, a differential effect of the emotional content on frontal ERPs was found between groups. In contrast to the control group, a reduced old/new effect indicates a reduced working memory capacity in the moderately depressed patients. This is suggested to be partially due to changes of the emotion/cognition coupling related to ruminations with preferably negative emotional connotation. However, the emotional content also affects recognition performance in the depressive patients.