Studies have shown that people with obsessive–compulsive disorder (OCD) have impairments in spatial working memory (SWM) performance. However, it remains unclear whether this deficit represents a cognitive endophenotype preceding symptoms or a correlate of OCD. We investigated SWM in 69 people with OCD, 77 unaffected first-degree relatives of people with OCD and 106 healthy control participants. Taking age effects into account, SWM performance was best in healthy controls, intermediate in relatives and worst in OCD participants. However, since performance did not differ significantly between healthy controls and relatives, our study does not fully support SWM performance as a core cognitive endophenotype of OCD.

Objectives: The aim of this study was to explore the relationship between cognitive and white matter deterioration in a group of participants with spinocerebellar ataxia type 2 (SCA2). Methods: Fourteen genetically confirmed participants with SCA2 and 14 aged-matched controls participated in the study. Diffusion tensor imaging tract-based spatial statistics were performed to analyze structural white matter integrity. Significant group differences in the mean diffusivity were correlated with SCA2 cognitive deficits. Results: Our analysis revealed higher mean diffusivity in the SCA2 group in cerebellar white matter, medial lemniscus, and middle cerebellar peduncle, among other regions. Cognitive scores correlated with white matter mean diffusivity in the parahippocampal area, inferior frontal and supramarginal gyri and the stria terminalis. Conclusions: Our findings show significant correlations between white matter microstructural damage in key areas affected in SCA2 and cognitive deficits. These findings result in a more comprehensive understanding of the effect of the neurodegenerative process in people with SCA2. (JINS, 2016, 22, 486–491)

Developmental psychophysiologists working with infants have no commonly accepted frequency definitions of EEG waves or rhythms. The purpose of this study was to investigate the task-related power changes in three infant EEG frequency bands during the performance of a spatial working memory task by 8-month-old infants. EEG data were divided into three frequency bands: 3–5 Hz, 6–9 Hz, and 10–12 Hz. Although all three frequency bands showed some level of discrimination of baseline from task and among different processing stages of cognitive activity, only the 6–9 Hz band consistently exhibited these capabilities and distinguished the correct from incorrect responses. These data may form the foundation for defining EEG frequency bands that are appropriate for use with infant research participants and for understanding the function of these frequencies during cognitive activity.