A low-stress restraint procedure for EEG acquisition in awake rats

A restraint procedure was developed to reduce movement-related artifacts during the acquisition of EEG data from unanesthetized, unparalyzed rats. It combines the low-stress properties of a cloth restraint bag with the improved immobility of a rigid restraint device. The spontaneous behavior of the rat facilitates both the induction of and the subsequent release from restraint.     

Predictors of therapeutic response to treatments for depression: a review of electrophysiologic and dichotic listening studies

There are few clinical or biologic predictors of response to treatments for depression. This article reviews growing evidence that electrophysiologic and neurocognitive measures of brain function may be of value as predictors of therapeutic response to antidepressants. Initial studies using dichotic listening, quantitative electroencephalography, or event-related brain potential measures have found differences between treatment responsive and nonresponsive subgroups of depressed patients. The neurophysiologic basis for these differences and the potential clinical utility of electrophysiologic and dichotic predictors of treatment outcome remain to be determined in future studies.     

Cognitive and temperamental vulnerability to depression: Longitudinal associations with regional cortical activity

Posterior cortical activity may be related to individual differences in temperamental emotionality, especially traits implicated in depression vulnerability. We previously reported that electroencephalographic (EEG) indices of cortical activity in posterior regions were associated with temperamental positive emotionality (PE) in early childhood. This project examined whether EEG indices of regional cortical activity, assessed at age 5–6, were associated with child temperament and cognitive vulnerability to depression, assessed at age 7. Asymmetry in posterior cortical activity measured at age 5–6 was associated with PE at follow-up at age 7, and with greater helplessness during a standardised laboratory task simulating a mild interpersonal rejection. Findings provide further support for the notion that low PE and depression are associated with similar patterns of cortical activity. Furthermore, these patterns of activity may have observable behavioural and cognitive correlates that are meaningfully linked to the phenomenology of depression.     

Reward sensitivity in depression: a biobehavioral study

The approach-withdrawal model posits 2 neural systems of motivation and emotion and hypothesizes that these systems are responsible for individual differences in emotional reactivity, or affective styles. The model also proposes that depression is characterized by a deficit in reward-seeking behavior (i.e., approach motivation) and is associated with a relative decrease in left frontal brain activity. The authors tested aspects of this model by comparing the electroencephalogram alpha power of depressed and nondepressed individuals during a task that manipulated approach motivation. The study found that control participants and individuals with late-onset depression exhibited the hypothesized increase in left frontal activity during the approach task but individuals with early-onset depression did not. This suggests that early-onset depression may be associated with a deficit in the hypothesized approach motivation system.     

Electroencephalographic asymmetries in adolescents with major depression: influence of comorbidity with anxiety disorders

This study examined whether adolescents with major depressive disorder (MDD) display the abnormal electroencephalographic (EEG) alpha asymmetries found in depressed adults. Resting EEG was recorded in 25 right-handed female outpatients (19 with MDD, 11 of whom also had a current anxiety disorder; 6 with anxiety disorders only) and 10 non-ill controls. In contrast to the non-ill controls, adolescents having MDD but no anxiety disorder showed alpha asymmetry indicative of less activation over right than over left posterior sites. Within the MDD patient group, comorbid anxiety disorders reduced the posterior alpha asymmetry, supporting the potential importance of evaluating anxiety in studies of regional brain activation in adolescent MDD. These preliminary findings are similar to those from adult studies that suggest that MDD is associated with right parietotemporal hypoactivation.