scholarly journals The human vestibular cortex: functional anatomy, connectivity and the effect of vestibular disease

2021 ◽  
Author(s):  
Richard Tolulope Ibitoye ◽  
Emma-Jane Mallas ◽  
Niall J Bourke ◽  
Diego Kaski ◽  
Adolfo Miguel Bronstein ◽  
...  
Keyword(s):  
Functional Mri ◽  
Visual Motion ◽  
Functional Anatomy ◽  
Slow Phase ◽  
Lateral Part ◽  
Vestibular Cortex ◽  
Vestibular Disease ◽  
Caloric Stimulation ◽  
Human Connectome Project ◽  
Visual Dependence

Area OP2 in the posterior peri-sylvian cortex has been proposed to be the core human vestibular cortex. We defined the functional anatomy of OP2 using spatially constrained independent component analysis of functional MRI data from the Human Connectome Project. Ten distinct subregions were identified. Most subregions showed significant connectivity to other areas with vestibular function: the parietal opercula, the primary somatosensory cortex, the supracalcarine cortex, the left inferior parietal lobule and the anterior cingulate cortex. OP2 responses to vestibular and visual-motion were analysed in 17 controls and 17 right-sided unilateral vestibular lesion patients (vestibular neuritis) who had previously undergone caloric and optokinetic stimulation during functional MRI. In controls, a posterior part of right OP2 showed: (a) direction-selective responses to visual motion; and (b) activation during caloric stimulation that correlated positively with perceived self-motion, and negatively with visual dependence. Patients showed abnormal OP2 activity, with an absence of visual or caloric activation of the healthy ear and no correlations with dizziness or visual dependence despite normal brainstem responses to caloric stimulation (slow-phase nystagmus velocity). A lateral part of right OP2 showed activity that correlated with chronic dizziness (situational vertigo) in patients. Our results define the functional anatomy of OP2 in health and disease. A posterior subregion of right OP2 shows strong functional connectivity to other vestibular regions and a visuo-vestibular profile that becomes profoundly disrupted after vestibular disease. In vestibular patients, a lateral subregion of right OP2 shows responses linked to the challenging long-term symptoms which define poorer clinical outcomes.

The human vestibular cortex: Functional anatomy, connectivity and the effect of peripheral vestibular disease

2021 ◽  
Vol 429 ◽  
pp. 117724
Author(s):  
Richard Ibitoye ◽  
Emma-Jane Mallas ◽  
Niall Bourke ◽  
Diego Kaski ◽  
Adolfo Bronstein ◽  
...  
Keyword(s):  
Functional Anatomy ◽  
Vestibular Cortex ◽  
Vestibular Disease

Vestibular Function in the Fetal Sheep

1998 ◽  
Vol 118 (5) ◽  
pp. 571-575
Author(s):  
Patrick J. Antonelli ◽  
Robert M. Abrams ◽  
Kenneth J. Gerhardt ◽  
Matthias Schwab ◽  
Reinhard Bauer
Keyword(s):  
Body Temperature ◽  
Vestibular System ◽  
Cold Water ◽  
Fetal Brain ◽  
Vestibular Function ◽  
Brain Maturation ◽  
Slow Phase ◽  
Facial Skin ◽  
Fetal Sheep ◽  
Caloric Stimulation

Little is known about the functional development of the vestibular system before birth. The purpose of this study was to determine whether vestibular response to caloric stimulation could be elicited in the fetal sheep in utero. Late gestational fetal sheep ( n = 6) were instrumented through a midline hysterotomy. Copper caloric probes were inserted into the right bulla and beneath the left facial skin. Electrodes were placed in the skull for monitoring of electro-ocular activity. At least 3 days after surgery the probes were irrigated with water (100 ml/minute) at body temperature, 46° C, and 6° C. Cold water infusion of the bulla consistently produced well-recognized, slow-phase deviations followed by saccades directed contralaterally, findings consistent with vestibular nystagmus. The direction of the response reversed with warm water irrigation. The response was absent with irrigation at fetal body temperature. Only random eye movements were observed in response to caloric stimulation of the facial skin, regardless of water temperature. These results demonstrate that the sheep vestibular system is functioning prenatally. The importance of vestibular function for normal fetal brain maturation may be revealed in future studies using this animal model. (Otolaryngol Head Neck Surg 1998;118:571–5.)

Variability and habituation of nystagmic responses to hot caloric stimulation of normal subjects

1982 ◽  
Vol 96 (7) ◽  
pp. 599-612 ◽  
Author(s):  
P. G. Davey ◽  
E. S. Harpur ◽  
F. Jabeen ◽  
D. Shannon ◽  
P. M. Shenoi
Keyword(s):  
Phase Velocity ◽  
Screening Method ◽  
Normal Subjects ◽  
Mean Value ◽  
Slow Phase ◽  
Caloric Test ◽  
Maximum Frequency ◽  
Slow Phase Velocity ◽  
Caloric Stimulation ◽  
Vestibular Toxicity

AbstractExperiments were performed on 25 otoneurologically ‘normal’ subjects to evaluate the hot caloric test as a screening test for aminoglycoside vestibular toxicity.Using portable equipment under non-ideal conditions, it was found that there was a large inter-subject variability in nystagmic response and that, instead of a random test-retest variability, a systagmic variation in response occurred on repeated caloric stimulation with water at 44°C.A response deline (habituation) evident in both the maximum slow phase velocity and the maximum frequency occurred at second test, although the inter-test interval ranged from 24 to 72 hours.After a 3-month interval with no intervening tests, the mean value of the maximum frequency reverted back to the original level. However, there was still a significant reduction in maximum slow phase velocity at this time. Some individuals had a sustanined reduction in both parameters.Hence it is concluded that the hot caloric test, used under the conditions described in this study, is not a suitable serial screening method for aminoglycoside vestibular toxicity. The reproducibility of this test under other conditions, or any other caloric test, should be established in normal subjects befre employing, it as a serial screen for aminoglycoside vestibular toxicity.

scholarly journals The parieto-insular vestibular cortex in humans: more than a single area?

2018 ◽  
Vol 120 (3) ◽  
pp. 1438-1450 ◽  
Author(s):  
Sebastian M. Frank ◽  
Mark W. Greenlee
Keyword(s):  
Nonhuman Primate ◽  
Visual Motion ◽  
Insular Cortex ◽  
Vestibular Cortex ◽  
Anatomical Structures ◽  
The Core ◽  
Primate Brain ◽  
Cortex Area ◽  
Posterior Insula ◽  
And Function

Here, we review the structure and function of a core region in the vestibular cortex of humans that is located in the midposterior Sylvian fissure and referred to as the parieto-insular vestibular cortex (PIVC). Previous studies have investigated PIVC by using vestibular or visual motion stimuli and have observed activations that were distributed across multiple anatomical structures, including the temporo-parietal junction, retroinsula, parietal operculum, and posterior insula. However, it has remained unclear whether all of these anatomical areas correspond to PIVC and whether PIVC responds to both vestibular and visual stimuli. Recent results suggest that the region that has been referred to as PIVC in previous studies consists of multiple areas with different anatomical correlates and different functional specializations. Specifically, a vestibular but not visual area is located in the parietal operculum, close to the posterior insula, and likely corresponds to the nonhuman primate PIVC, while a visual-vestibular area is located in the retroinsular cortex and is referred to, for historical reasons, as the posterior insular cortex area (PIC). In this article, we review the anatomy, connectivity, and function of PIVC and PIC and propose that the core of the human vestibular cortex consists of at least two separate areas, which we refer to together as PIVC+. We also review the organization in the nonhuman primate brain and show that there are parallels to the proposed organization in humans.

scholarly journals Integrating Task-Based Functional MRI Across Tasks Markedly Boosts Prediction and Reliability of Brain-Cognition Relationship

2021 ◽  
Author(s):  
Alina Tetereva ◽  
Jean Li ◽  
Jeremiah Deng ◽  
Argyris Stringaris ◽  
Narun Pat
Keyword(s):  
Individual Differences ◽  
Functional Mri ◽  
Cognitive Abilities ◽  
Brain Mri ◽  
Integration Theory ◽  
Sources Of Information ◽  
Resting State Functional Connectivity ◽  
Retest Reliability ◽  
Human Connectome Project ◽  
Test Retest Reliability

Capturing individual differences in cognitive abilities is central to human neuroscience. Yet our ability to estimate cognitive abilities via brain MRI is still poor in both prediction and reliability. Our study tested if this inability was partly due to the over-reliance on 1) non-task MRI modalities and 2) single modalities. We directly compared predictive models comprising of different sets of MRI modalities (e.g., task vs. non-task). Using the Human Connectome Project (n=873 humans, 473 females, after exclusions), we integrated task-based functional MRI (tfMRI) across seven tasks along with other non-task MRI modalities (structural MRI, resting-state functional connectivity) via a machine-learning, stacking approach. The model integrating all modalities provided unprecedented prediction (r=.581) and excellent test-retest reliability (ICC>.75) in capturing general cognitive abilities. Importantly, comparing to the model integrating among non-task modalities (r=.367), integrating tfMRI across tasks led to significantly higher prediction (r=.544) while still providing excellent test-retest reliability (ICC>.75). The model integrating tfMRI across tasks was driven by areas in the frontoparietal network and by tasks that are cognition-related (working-memory, relational processing, and language). This result is consistent with the parieto-frontal integration theory of intelligence. Accordingly, our results sharply contradict the recently popular notion that tfMRI is not appropriate for capturing individual differences in cognition. Instead, our study suggests that tfMRI, when used appropriately (i.e., by drawing information across the whole brain and across tasks and by integrating with other modalities), provides predictive and reliable sources of information for individual differences in cognitive abilities, more so than non-task modalities.

scholarly journals What Is the Test-Retest Reliability of Common Task-Functional MRI Measures? New Empirical Evidence and a Meta-Analysis

2020 ◽  
Vol 31 (7) ◽  
pp. 792-806 ◽  
Author(s):  
Maxwell L. Elliott ◽  
Annchen R. Knodt ◽  
David Ireland ◽  
Meriwether L. Morris ◽  
Richie Poulton ◽  
...  
Keyword(s):  
Functional Mri ◽  
Biomarker Discovery ◽  
Disease Risk ◽  
Brain Activity ◽  
Meta Analysis ◽  
A Priori ◽  
Intraclass Correlation ◽  
Common Task ◽  
Human Connectome Project ◽  
State Of Affairs

Identifying brain biomarkers of disease risk is a growing priority in neuroscience. The ability to identify meaningful biomarkers is limited by measurement reliability; unreliable measures are unsuitable for predicting clinical outcomes. Measuring brain activity using task functional MRI (fMRI) is a major focus of biomarker development; however, the reliability of task fMRI has not been systematically evaluated. We present converging evidence demonstrating poor reliability of task-fMRI measures. First, a meta-analysis of 90 experiments ( N = 1,008) revealed poor overall reliability—mean intraclass correlation coefficient (ICC) = .397. Second, the test-retest reliabilities of activity in a priori regions of interest across 11 common fMRI tasks collected by the Human Connectome Project ( N = 45) and the Dunedin Study ( N = 20) were poor (ICCs = .067–.485). Collectively, these findings demonstrate that common task-fMRI measures are not currently suitable for brain biomarker discovery or for individual-differences research. We review how this state of affairs came to be and highlight avenues for improving task-fMRI reliability.

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