Neural Mechanisms of Attention

Following the discovery of context-dependent synchronization of oscillatory neuronal responses in the visual system, novel methods of time series analysis have been developed for the examination of task- and performance-related oscillatory activity and its synchronization. Studies employing these advanced techniques revealed that synchronization of oscillatory responses in the beta- and gamma-band is involved in a variety of cognitive functions, such as perceptual grouping, attention-dependent stimulus selection, routing of signals across distributed cortical networks, sensory-motor integration, working memory, and perceptual awareness. Here, we review evidence that certain brain disorders, such as schizophrenia, epilepsy, autism, Alzheimer's disease, and Parkinson's are associated with abnormal neural synchronization. The data suggest close correlations between abnormalities in neuronal synchronization and cognitive dysfunctions, emphasizing the importance of temporal coordination. Thus, focused search for abnormalities in temporal patterning may be of considerable clinical relevance.

Emotion regulation strategies are thought to differ in when and how they influence the emotion-generative process. However, no study to date has directly probed the neural bases of two contrasting (e.g., cognitive versus behavioral) emotion regulation strategies. This study used functional magnetic resonance imaging (fMRI) to examine cognitive reappraisal (a cognitive strategy thought to have its impact early in the emotion-generative process) and expressive suppression (a behavioral strategy thought to have its impact later in the emotion-generative process). Seventeen women viewed 15 sec neutral and negative emotion-eliciting films under four conditions--watch-neutral, watch-negative, reappraise-negative, and suppress-negative--while providing emotion experience ratings and having their facial expressions videotaped. Reappraisal resulted in early (0-4.5 sec) prefrontal cortex (PFC) responses, decreased negative emotion experience, and decreased amygdala and insular responses. Suppression produced late (10.5-15 sec) PFC responses, decreased negative emotion behavior and experience, but increased amygdala and insular responses. These findings demonstrate the differential efficacy of reappraisal and suppression on emotional experience, facial behavior, and neural response and highlight intriguing differences in the temporal dynamics of these two emotion regulation strategies.