Dr Månsson's Research Lab

Estimated Gray Matter Volume Rapidly Changes after a Short Motor Task

Wed, 09 Feb 2022 10:43:57 -0800

What are your participants doing while youacquire the anatomical MRI brain scans? Our latest show that estimated gray matter volume (GMV) rapidly changes after a 2-minute short motor task (t.ly/gFwU) Does this common estimate really represent GMV?

We acquired up to 14 T1-weighted and 8 BOLD-fMRI images from 51 subjects while resting or performing a finger-tapping task (FTT; á 2 min) for 30 or 60 minutes.

Estimated GMV decreased in motor regions during FTT compared with rest. These effects in motor cortex were specific to taskexecution, and differed from time-related GMV changes occurring over 30 to 60 min of FTT exercise. Are these rapid GMV changes BOLD-related?

Task-related motor cortex BOLD signals did notoverlap nor correlate with any effects observed on T1-w GMV estimates, evincing that BOLD signals cannot fully explain the rapid task-induced changes in estimated GMV.

Estimates of GMV were not related to behavioural performance, but cerebellum neural response changes (BOLD) were related to FTT improvements.

We previously showed that passive image viewinglead to enlargements in visual cortex GMV (t.ly/8zJZ). Here, an active finger-tapping task induced motorcortex GMV changes and we conclude that behavior-related GMV changes may poseserious questions to reproducibility across studies.

Shout out to all co-authors and collaboration at Kaorlinska Institutet, Unversity of Gothenburg, and Stockholm University.

Moment-to-moment brain signal variability reliably predicts psychiatric treatment outcome

Sun, 17 Oct 2021 06:53:05 -0700

Biomarkers in psychiatry remain elusive, and typical BOLD fMRI measures show low reliability. In contrast, moment-to-moment variability in brain activity can reliably index the effectiveness of neural systems, but has so far not been linked to psychiatric treatment response.

In a sample of social anxiety patients, we recorded BOLD during resting state and emotional face viewing (a social anxiety-relevant task) in two fMRI sessions, 11 weeks apart. Afterwards, patients received a 9-week CBT and clinical symptoms were monitored pre and post CBT.

We showed that BOLD variability strongly predicted CBT outcome (r[Predict,Actual] = .77). In particular, task-related BOLD variability was a better predictor than 1) social anxiety self-reports, 2) resting-state variability, and 3) standard mean-based BOLD measures.

Task-related BOLD variability exhibited excellent test-retest reliability of treatment outcome prediction (ICC=.80). Strikingly, high reliability and prediction accuracy were achieved despite the extraordinarily short face task (<3 min).

Notably, task-based lower variability in visual cortex was the strongest CBT outcome predictor. What could this mean? These patients may show a heightened focus on emotional content at the cost of an incomplete sensory representation processing.

Indeed, lower variability in visual cortex is expected when individuals do not fully process the complexity of the input (Read More