Poststroke acute dysexecutive syndrome, a disorder resulting from minor stroke due to disruption of network dynamics

Figures

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  Fig. 1.. Overlay plots of cerebral activation time courses corresponding to each of the predefined areas of interest highlighted in green (created by combining aparc labels as described in our Methods section): the occipital lobe (visual response), fusiform gyrus (M170 word form response) and lateral temporal lobe (M400 semantic processing response) for stroke patients and controls at visit 1 (n = 9 patients and 8 controls). Responses shown correspond to the average response to all words included in the analysis. Each trace corresponds to one virtual current dipole in the source model. dSPM, related to a standardized Z score, represents the current estimate normalized by the variance of the noise estimate (34). Note the decreased amplitude and lack of clear peaks for stroke patients compared to controls.

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  Fig. 2.. Clinical MRI scans of the nine stroke patients (diffusion weighted imaging sequences) obtained during their hospital admission showing small acute infarcts without involvement of areas typically associated with cognitive dysfunction.

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  Fig. 3.. MEG rms analysis demonstrating a significant difference in activation patterns between 50 and 600 ms for both words and images at visit 1 for stroke patients versus controls. This difference was no longer significant for words at visit 2. Activation patterns appear more visually similar between groups at visit 2, especially when compared to the visit 1 activation patterns of only the participants (n = 6 patients and 6 controls) who had repeat imaging performed (Inlays). Error bars represent the within-subject SEM (48).

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  Fig. 4.. (A) At visit 1 there are task effects by the group (n = 9 patients and 8 controls) present within the fusiform gyrus and lateral temporal lobe. Bars indicate the temporal extent of significant clusters found in the spatiotemporal cluster-based analysis. Time courses are shown within ROIs defined from significant clusters, outlined in red. Times series demonstrate that for controls, the shape of the waveform varies as a function of task while remaining relatively flat and typically around zero for stroke patients. dSPM, related to a Z score, represents the current estimate normalized by the variance of the noise estimate but is averaged across sources in the ROI, which accounts for the lower amplitude compared to Fig. 1. Error bars indicate the within-subject SEM. (B) Waveforms remain consistent for both stroke patients and controls across visits. Only subjects with complete data from visits 1 and 2 (n = 6 patients and 6 controls) are displayed for comparison.