Distinct neuropsychological profiles of three major symptom dimensions in obsessive-compulsive disorder.

Recent neuroimaging studies have suggested that different symptom dimensions are mediated by partially distinct neural systems in obsessive-compulsive disorder (OCD). However, the correlations between neuropsychological profiles and symptom dimensions in OCD are unknown. The aim of this study was to examine the extent to which OCD symptom dimensions were associated with episodic memory and attention and executive functions. The symptom dimensions of 63 patients with OCD were assessed using both the Padua Inventory and the Y-BOCS symptom checklist. Then, we administered the Logical Memory (LM) subset of the Wechsler Memory Scale-Revised (WMR-R) test and evaluated inhibition (Stroop test, Trail Making test) and cognitive flexibility (Digit Symbol test, Letter Fluency, and Category Fluency). While associations were observed between scores on the contamination/cleaning dimension and better performances on the LM and Trail Making tests, associations were also observed between scores on the aggressive/checking dimension and poorer performances on the Trail Making test. In addition, we found that scores on the symmetry/ordering dimension were associated with poorer performances on the LM and Trail Making tests. Our results support the hypothesis that different symptoms may represent distinct and partially overlapping neurocognitive networks in OCD patients.

Ictal electroencephalographic correlates of posttreatment neuropsychological changes in electroconvulsive therapy: a hypothesis-generation study.

OBJECTIVES: Electroconvulsive therapy (ECT) has been associated with memory and neuropsychological changes, but which features of ECT are associated with those changes have not been well investigated. The aim of this hypothesis-generation study was to examine correlations between ictal electroencephalographic (EEG) characteristics and cognitive side effects after ECT. METHODS: Eight patients with major depressive disorder were examined with the Wechsler Memory Scale-Revised (WMS-R), the Stroop test, the Trail Making Test, and verbal fluency before and after ECT treatment. Seven ictal EEG measurements (eg, slow-wave phase amplitude, postictal suppression) were manually rated by 3 independent psychiatrists. The correlations between ictal EEG measurements, changes in WMS-R subset scores, and non-memory-related neuropsychological assessments were examined with Spearman rank correlation. RESULTS: Verbal memory, general memory, attention/concentration, delayed memory of WMS-R subset scores, and the Stroop test scores improved significantly after ECT treatment. Postictal suppression and slow-wave amplitude correlated positively with delayed memory and visual/verbal discrepancy score. Slow-wave amplitude correlated negatively with letter fluency. The longer the polyspike wave duration, the higher the attention/concentration test results. CONCLUSIONS: Certain ictal EEG measurements were associated with changes in several neuropsychological test results that had improved 2 weeks after the final ECT treatment. A hypothesis-testing study with a larger sample is needed to verify the relationships between EEG measurements and neuropsychological test performance.

Effects of melatonin injection on running-wheel activity and body temperature differ by the time of day.

Melatonin, which is released from the pineal gland, influences many physiological events concerned with circadian rhythm. Body temperature levels and rhythmicity are tightly coupled with locomotor activity. To understand the functions of melatonin, we determined the effects of melatonin injection on locomotor activity measured by running-wheel activity and body temperature in rats. The rats were kept under a 12-h light and 12-h dark lighting condition, with the light on at zeitgeber time 0 (ZT 0, correspond to 7:00 JST). Melatonin injection, between ZT 3 and ZT 5 (light period) and between ZT 15 and ZT 17 (dark period), attenuated the wheel-running activity in a dose-dependent manner (10 microg to 1 mg/100 g body weight [bw]). A significant attenuation of activity by melatonin was recognized when injected at ZT 8, ZT 14 and ZT 20. After the injection of melatonin, the animal's body temperature was elevated at ZT 2 and ZT 8 (during light), while it fell at ZT 14 and ZT 20 (during darkness). We propose a plausible explanation underlying the observed changes in body temperature during the light and dark periods accompanying the suppression of activity induced by melatonin.