Digital Mind 🧠

🪵 The Threshold

Tinnitus patients show reduced default mode network connectivity and a blunted task effect.

Properties2
tagsja-picks, xref, question, factual_claims, trade, corroborated, category/factual-claims
aliases@van_dijk_physiology_2016, loc. 2700

4 min read

Tinnitus patients show reduced default mode network connectivity and a blunted task effect.

Evidence

Specifically in patients with tinnitus, the DMN does not clearly show a task-effect, which in contrast is clearly present in controls. This observation enhances the hypothesis that subjects with tinnitus cannot get the ‘rest’ that is necessary for a healthy life. In conclusion, we attribute the pattern of reduced connectivity in the DMN to the unremitting engaging effect of the tinnitus percept. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2747

When looking at the map strength, a proxy for functional connectivity, patients consistently show decreased functional connectivity (panels B and F). Moreover, whereas controls show a clear task-effect, as would be expected for the DMN, this task-effect is much smaller in patients (panel B). — Dijk, Pim van, Physiology, Psychoacoustics and…, 2737

In both the DMN and the latter component, there are adjacent voxels that show a clear and significant group difference (p < 0.001 for each of the maps, corresponding to a F-value of 12.71). When looking at the map strength, a proxy for functional connectivity, patients consistently show decreased functional connectivity (panels B and F). Moreover, whereas controls show a clear task-effect, as would be expected for the DMN, this task-effect is much smaller in patients (panel B). — Dijk, Pim van, Physiology, Psychoacoustics and…, 2729

Moreover, whereas controls show a clear task-effect, as would be expected for the DMN, this task-effect is much smaller in patients (panel B). … For the network with the visual cortex and cingulate gyrus (panel E), this task-effect is less clear (panel F) and shows in controls a decrease during resting state compared to watching a movie, presumably due to the lack of visual stimulation throughout the acquisition of resting-state data. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2729

We investigated tinnitus-related differences in functional networks in adults with tinnitus by means of a functional connectivity study. Previously it was found that various networks show differences in connectivity in patients with tinnitus compared to controls. How this relates to patients’ ongoing tinnitus and whether the ecological sensory environment modulates connectivity remains unknown.Twenty healthy controls and twenty patients suffering from chronic tinnitus were enrolled in this study. Except for the presence of tinnitus in the patient group, all subjects were selected to have normal or near-normal hearing. fMRI data were obtained in two different functional states. In one set of runs, subjects freely viewed emotionally salient movie fragments (“fixed-state”) while in the other they were not performing any task (“resting-state”). After data pre-processing, Principal Component Analysis was performed to obtain 25 components for all datasets. These were fed into an Independent Component Analysis (ICA), concatenating the data across both groups and both datasets, to obtain group-level networks of neural origin, each consisting of spatial maps with their respective time-courses. Subject-specific maps and their time-course were obtained by back-projection (Dual Regression). For each of the components a mixed-effects linear model was composed with factors group (tinnitus vs. controls), task (fixed-state vs. resting state) and their interaction. The neural components comprised the visual, sensorimotor, auditory, and limbic systems, the default mode, dorsal attention, executive-control, and frontoparietal networks, and the cerebellum. Most notably, the default mode network (DMN) was less extensive and shows significantly less connectivity in tinnitus patients than in controls. This group difference existed in both paradigms. At the same time, the DMN was stronger during resting-state than during fixed-state in the controls but not the patients. We attribute this pattern to the unremitting engaging effect of the tinnitus percept. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2701

Categorization

  • XREF: The claim that ongoing percepts rob the brain of needed rest links to the reader’s prior interest in chronic noise robbing quiet reflection. — connects to: Chronic tinnitus prevents the brain from entering the resting state normally.; A dysfunctional default-mode network links tinnitus with autism; Resting-state fMRI reveals connectivity differences in numerous brain regions in tinnitus. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2707 (+1 more)
  • QUESTION: Could reduced DMN connectivity in tinnitus relate to the attentional capture effects of phantom sound? Worth tracing this to the physiology-versus-perception debate in the book.
  • corroborated: 11 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 2747; Dijk, Pim van, Physiology, Psychoacoustics and…, 2737; Dijk, Pim van, Physiology, Psychoacoustics and…, 2729 (+1 more)

Broader Connections

✉️

Backlinks