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To have or not to have a break. Neural connectivity patterns during task-to-rest transitions in healthy subjects and patients with obsessive-compulsive disorder (OCD)

100%

Zurowski B., Kordon A., Hohagen F., Buetof S. J.

Acta Neurobiologiae Experimentalis

2017

tom 77

nr Suppl.1

INTRODUCTION: The investigation of resting state connectivity typically provides a static view on neuronal integration that does not capture dynamic transitions between rest and task-related network connectivity underlying real life functioning – particularly in neuropsychiatric disorders characterized by cognitive inflexibility and difficulties to disengage from cognitive processing. AIM(S): The aim of the present study was to characterize network connectivity differences between OCD patients and healthy controls. Using fcMRI, we explored whether engagement in a perceptual decision task has differential impact on subsequent topographical and timely aspects of neural connectivity. METHOD(S): fMRI data from 18 OCD and 14 healthy subjects was obtained using a 3T Siemens scanner before (fixation1), during, and after (fixation2) a luminance‑based perceptual decision task. For analysis SPM8 and CONN Toolbox were used. To test for differences in spontaneous and task-induced fcMRI study groups were contrasted in fixation1 and the decision block, respectively. In a second analysis, fixation1 was compared to fixation2 to determine the impact of the decision task. In addition, the fixation2 period was segmented into three time windows which were then contrasted separately with fixation1 and with each other. RESULTS: Healthy controls had stronger connections between the orbitofrontal cortex and superior and medial frontal gyri during fixation1 and during the decision task. The segmentation of fixation 2 into 3 time windows revealed that only the 1. window differed significantly from fixation1 in controls. In contrast, the fcMRI discrepancy in OCD was significant across the entire period of fixation2. CONCLUSIONS: Healthy subjects and OCD patients show differences between pre‑task and post‑task resting state network connectivity, which is prolonged in OCD patients, however. The investigation of dynamic rather than static network connectivity is strongly encouraged both in healthy and neuropsychiatric populations. FINANCIAL SUPPORT: Medical Faculty of the University of Lübeck, Deutsche Forschungsgemeinschaft (DFG, Grant BR 1766/4), Federal Ministry of Education and Science (BMBF).

Behavioural and neural correlates of action selections:probing indecisiveness in obsessive-compulsive disorder

88%

Zurowski B., Arnoldussen A., Kordon A., Eimeren van T., Hohagen F.

Acta Neurobiologiae Experimentalis

2015

tom 75

nr Supl.

BACKGROUND AND AIMS: The observation of every-day problems in decision making in patients with obsessive-compulsive disorder (OCD) is reflected by their inclusion in psychometric scales for OCD. Experimentalstudiesin OCD patients did not consistently find deficits in DM, however. Our aim was to minimize the hypothesized influence of working memory capacity, reward/punishment processing upon feedback, planning and strategy on action selection performance and neural correlates thereof using fMRI. METHODS: We conducted an event-related 3T-fMRI study in 12 unmedicated OCD patients and 10 healthy controls. We used a forced-choice reaction time (RT) paradigm with parametrically increasing number of choice alternatives to be indicated by button press (0–4). Choices were based on abstract stimuli and rules, with no feedback provided. RESULTS: As expected both groups showed nearly errorless task performance and increasing RTs with increasing number of choice alternatives (0–4). This effect was paralleled by a parametrically increasing recruitment of a bilateral parieto-premotor-prefrontal cortical network and the cerebellum in all subjects. However, we did not observe any group differences applying a P=0.05 threshold with correction for multiple comparisons in SPM8. Analoguously, patients with OCD did not differ from controls regarding error rate or RT. CONCLUSIONS: Using a “purified” action selection paradigm we suggest that forming and executing simple decisions without switching contingencies and without delivering reward or punishment is unimpaired in OCD, both in behavioural and neural terms. Further studies will need to determine which additional task requirements associated with action selection may be responsible for observable deficits.

Ograniczanie wyników

2 Acta Neurobiologiae Experimentalis

2 Hohagen F.

2 Kordon A.

2 Zurowski B.

1 Arnoldussen A.

1 Buetof S. J.

1 Eimeren van T.

1 2017

1 2015

Wyniki wyszukiwania

To have or not to have a break. Neural connectivity patterns during task-to-rest transitions in healthy subjects and patients with obsessive-compulsive disorder (OCD)

Behavioural and neural correlates of action selections:probing indecisiveness in obsessive-compulsive disorder