Browsing by Author "Elonen, Jasmin"

To make fast and efficient decisions in changing environments, humans must plan their actions throughout their lives by maintaining and updating relevant information. Such goal-directed situations demand flexible adjustment of behavior and the suppression of task-irrelevant details. Executive dysfunctions in cognitive flexibility, working memory and inhibition have been related to aberrant prefrontal cortex functioning. The prefrontal cortex has previously been found to have an important role in these executive functions as a supervisory modulator and processor of information from posterior sensory brain areas. Structural and functional abnormalities in these brain areas have been found in attention deficit/hyperactivity disorder (ADHD). These impairments may be the underlying reason for problems in decision making and planning for people with ADHD. However how the brain’s oscillatory activity modulates different cognitive functions in areas relating to planning and decision making is still unclear. To investigate thisthe brain’s activity was measured with MEG while participants (21 ADHD patients, 28 controls) performed in Wisconsin card sorting test (WCST). WCST is a fast-paced task, where cards are sorted according to changing rule categories with the direction of feedback. The aim of this study was to investigate planning in adults with ADHD and a control group during WCST planning period and compare trials with previous feedback being correct or incorrect. Difference in the local neuronal activity in prefrontal and posterior areas were expected between the ADHD and control groups. Data-analysis and source modelling and reconstruction were conducted on the neuronal (MEG) data and structural (MRI) data. Statistical analyses were run for local neuronal amplitude dynamics and visualized within and between groups. The behavioral results of reaction times and hit rates did not show significant differences between groups. Clinical questionnaire scores did not correlate with reaction times. However, contrast of planning in correct-incorrect feedback trials within groups showed increased and decreased brain activity in delta, theta, alpha and beta oscillations. The control group showed activity in frontal, parietal, temporal, and occipital regions related to default mode, somatomotor with increased activity in the beta and alpha bands. For the ADHD group greatest positive activity was seen in beta band in frontal and parietal areas, but also in occipital regions. These activation sites were mostly related to dorsal and ventral attention and somatomotor networks but also to default mode and visual networks. Mostly temporal activity of suppressed delta, theta and alpha oscillations in the lateral areas was seen in the between groups comparison. These areas related to ventral attention and somatomotor networks. Impaired neuronal activity in the ADHD group was seen in weaker increased beta than the control group and the missing increased alpha oscillations. It remains for the future studies to interpret the roles of this oscillatory activity but direction towards impairments in cognitive functions like flexibility, working memory and inhibition in planning in ADHD. These data also suggest that planning in the WCST needs the flexible modulation of many cognitive functions and processes that are modulated by increased alpha and beta oscillations and the suppressed delta and theta oscillations.