Cognitive Brain Activity Research Articles

Neuroanatomical aspects of cognitive-behavioural therapy response in obsessive-compulsive disorder

Recent research has demonstrated that cognitive-behavioural therapy (CBT) for obsessive-compulsive disorder (OCD) can systematically modify cerebral metabolic activity in a manner which is significantly related to clinical outcome. A substantial body of research is reviewed which supports an involvement of neural circuitry connecting the orbitofrontal cortex, cingulate gyrus and basal ganglia in the expression of the symptoms of OCD. Data are presented which expand upon previous work demonstrating effects of CBT on functional interactions between limbic cortex and the basal ganglia. The relevance of these effects of CBT on brain function is discussed in the context of recent advances in our knowledge of cortical-basal ganglia physiology. The clinical importance of these data is best appreciated when they are seen to reflect the interactive nature of the relationships between cognitive choice, behavioural output and brain activity.

Between Sessions Reproducibility of Cognitive Task-Induced Brain Activation

Between Sessions Reproducibility of Cognitive Task-Induced Brain Activation

MEG-based imaging of focal neuronal current sources.

We describe a new approach to imaging neural current sources from measurements of the magnetoencephalogram (MEG) associated with sensory, motor, or cognitive brain activation. Many previous approaches to this problem have concentrated on the use of weighted minimum norm (WMN) inverse methods. While these methods ensure a unique solution, they do not introduce information specific to the MEG inverse problem, often producing overly smoothed solutions and exhibiting severe sensitivity to noise. We describe a Bayesian formulation of the inverse problem in which a Gibbs prior is constructed to reflect the sparse focal nature of neural current sources associated with evoked response data. We demonstrate the method with simulated and experimental phantom data, comparing its performance with several WMN methods.