Global Activation Patterns Research Articles

Exploring Implicit Biological Heterogeneity in ASD Diagnosis Using a Multi-Head Attention Graph Neural Network.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder exhibiting heterogeneous characteristics in patients, including variability in developmental progression and distinct neuroanatomical features influenced by sex and age. Recent advances in deep learning models based on functional connectivity (FC) graphs have produced promising results, but they have focused on generalized global activation patterns and failed to capture specialized regional characteristics and accurately assess disease indications. To overcome these limitations, we propose a novel deep learning method that models FC with multi-head attention, which enables simultaneous modeling of the intricate and variable patterns of brain connectivity associated with ASD, effectively extracting abnormal patterns of brain connectivity. The proposed method not only identifies region-specific correlations but also emphasizes connections at specific, transient time points from diverse perspectives. The extracted FC is transformed into a graph, assigning weighted labels to the edges to reflect the degree of correlation, which is then processed using a graph neural network capable of handling edge labels. Experiments on the autism brain imaging data exchange (ABIDE) I and II datasets, which include a heterogeneous cohort, showed superior performance over the state-of-the-art methods, improving accuracy by up to 3.7%p. The incorporation of multi-head attention in FC analysis markedly improved the distinction between typical brains and those affected by ASD. Additionally, the ablation study validated diverse brain characteristics in ASD patients across different ages and sexes, offering insightful interpretations. These results emphasize the effectiveness of the method in enhancing diagnostic accuracy and its potential in advancing neurological research for ASD diagnosis.

Engaging distributed cortical and cerebellar networks through motor execution, observation, and imagery.

When we interact with the environment around us, we are sometimes active participants, making directed physical motor movements and other times only mentally engaging with our environment, taking in sensory information and internally planning our next move without directed physical movement. Traditionally, cortical motor regions and key subcortical structures such as the cerebellum have been tightly linked to motor initiation, coordination, and directed motor behavior. However, recent neuroimaging studies have noted the activation of the cerebellum and wider cortical networks specifically during various forms of motor processing, including the observations of actions and mental rehearsal of movements through motor imagery. This phenomenon of cognitive engagement of traditional motor networks raises the question of how these brain regions are involved in the initiation of movement without physical motor output. Here, we will review evidence for distributed brain network activation during motor execution, observation, and imagery in human neuroimaging studies as well as the potential for cerebellar involvement specifically in motor-related cognition. Converging evidence suggests that a common global brain network is involved in both movement execution and motor observation or imagery, with specific task-dependent shifts in these global activation patterns. We will further discuss underlying cross-species anatomical support for these cognitive motor-related functions as well as the role of cerebrocerebellar communication during action observation and motor imagery.

Unity and diversity of neural representation in executive functions.

Although the unity and diversity model of executive functions (EFs) has been replicated, there are some studies questioning the validity of the EFs construct. This debate can be partially resolved by directly combining the brain activity pattern in different executive control processes. Previous univariate activation studies have suggested that the neural substrates of different EFs (e.g., updating, inhibiting, and shifting) involve common and distinct brain regions. However, the underlying multivariate neural representation of EFs in terms of unity and diversity is still elusive. Here, we employed the n-back task, stop signal task, and category switching task to investigate the characteristic of the neural representation in the three EF domains. At the global level, multivoxel pattern analysis revealed that a three-way classifier built with global activation pattern successfully distinguished the three EF tasks. At the local level, although most overlapping activations exhibit lower neural representational similarity, the inferior frontal junction showed similar neural representation across the three EFs, which was further confirmed by searchlight analysis that additionally revealed other similar representational regions were located in the presupplementary motor area extend to dorsal midcingulate cortex. In addition, using machine learning-based predictive framework, the resting-state functional networks built with the representational regions of EFs predicted intellectual abilities to some extent in a large independent sample. These findings suggest that different EFs are characterized by dissociable global neural representation but also share similar local neural representation, which contributes to understanding the neural correlates of the unity and diversity of EFs from an integrated framework. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Local neuronal relational structures underlying the contents of human conscious experience.

While most theories of consciousness posit some kind of dependence on global network activities, I consider here an alternative, localist perspective—in which localized cortical regions each underlie the emergence of a unique category of conscious experience. Under this perspective, the large-scale activation often found in the cortex is a consequence of the complexity of typical conscious experiences rather than an obligatory condition for the emergence of conscious awareness—which can flexibly shift, depending on the richness of its contents, from local to more global activation patterns. This perspective fits a massive body of human imaging, recordings, lesions and stimulation data but opens a fundamental problem: how can the information, defining each content, be derived locally in each cortical region. Here, I will discuss a solution echoing pioneering structuralist ideas in which the content of a conscious experience is defined by its relationship to all other contents within an experiential category. In neuronal terms, this relationship structure between contents is embodied by the local geometry of similarity distances between cortical activation patterns generated during each conscious experience, likely mediated via networks of local neuronal connections. Thus, in order for any conscious experience to appear in an individual’s mind, two central conditions must be met. First, a specific configural pattern (“bar-code”) of neuronal activity must appear within a local relational geometry, i.e. a cortical area. Second, the individual neurons underlying the activated pattern must be bound into a unified functional ensemble through a burst of recurrent neuronal firing: local “ignitions”.

The utility of a novel mapping algorithm utilizing vectors and global pattern of propagation for scar-related atrial tachycardias.

Activation maps of scar-related atrial tachycardias (AT) can be challenging to interpret due to difficulty in inaccurate annotation of electrograms, and an arbitrarily predefined mapping window. A novel mapping software integrating vector data and applying an algorithmic solution taking into consideration global activation pattern has been recently described (Coherent™, Biosense Webster "Investigational"). We aimed to assess the investigational algorithm to determine the mechanism of AT compared with the standard algorithm. This study included patients who underwent ablation of scar-related AT using the Carto 3 and the standard activation algorithm. The mapping data were analyzed retrospectively using the investigational algorithm, and the mechanisms were evaluated by two independent electrophysiologists. A total of 77 scar-related AT activation maps were analyzed (89.6% left atrium, median tachycardia cycle length of 273 ms). Of those, 67 cases with a confirmed mechanism of arrhythmia were used to compare the activation software. The actual mechanism of the arrhythmia was more likely to be identified with the investigational algorithm (67.2% vs. 44.8%, p = .009). In five patients with dual-loop circuits, 3/5 (60%) were correctly identified by the investigational algorithm compared to 0/5 (0%) with the standard software. The reduced atrial voltage was prone to lead to less capable identification of mechanism (p for trend: .05). The investigational algorithm showed higher inter-reviewer agreement (Cohen's kappa .62 vs. .47). In patients with scar-related ATs, activation mapping algorithms integrating vector data and "best-fit" propagation solution may help in identifying the mechanism and the successful site of termination.

Cortical propagation tracks functional recovery after stroke.

Stroke is a debilitating condition affecting millions of people worldwide. The development of improved rehabilitation therapies rests on finding biomarkers suitable for tracking functional damage and recovery. To achieve this goal, we perform a spatiotemporal analysis of cortical activity obtained by wide-field calcium images in mice before and after stroke. We compare spontaneous recovery with three different post-stroke rehabilitation paradigms, motor training alone, pharmacological contralesional inactivation and both combined. We identify three novel indicators that are able to track how movement-evoked global activation patterns are impaired by stroke and evolve during rehabilitation: the duration, the smoothness, and the angle of individual propagation events. Results show that, compared to pre-stroke conditions, propagation of cortical activity in the subacute phase right after stroke is slowed down and more irregular. When comparing rehabilitation paradigms, we find that mice treated with both motor training and pharmacological intervention, the only group associated with generalized recovery, manifest new propagation patterns, that are even faster and smoother than before the stroke. In conclusion, our new spatiotemporal propagation indicators could represent promising biomarkers that are able to uncover neural correlates not only of motor deficits caused by stroke but also of functional recovery during rehabilitation. In turn, these insights could pave the way towards more targeted post-stroke therapies.

The Utility of a Novel Mapping Algorithm Utilizing Vectors and Global Pattern for Atrial Tachycardias

Background: Activation maps of scar-related atrial tachycardias (AT) can be challenging to interpret due to difficulty in inaccurate annotation of electrograms, and an arbitrarily predefined mapping window. A novel mapping software integrating vector data and applying an algorithmic solution taking into consideration global activation pattern has been recently described (CoherentTM, Biosense Webster Investigational). Objective: We aimed to assess the investigational algorithm to determine the mechanism of AT compared with the standard algorithm. Methods: This study included patients who underwent ablation of scar-related AT using the Carto 3 and the standard activation algorithm. The mapping data was analyzed retrospectively using the investigational algorithm, and the mechanisms were evaluated by two independent electrophysiologists. Results: A total of 77 scar-related AT activation maps were analyzed (89.6% left atrium, median tachycardia cycle length of 273 milliseconds). Of those, 67 cases with confirmed mechanism of the arrhythmia were used to compare the activation software. The actual mechanism of the arrhythmia was more likely to be identified with the investigational algorithm (67.2% vs 44.8%, P=0.009). In 5 patients with dual-loop circuits, 3/5 (60%) were correctly identified by the investigational algorithm compared to 0/5 (0%) with the standard software. The reduced atrial voltage was prone to lead to less capable identification of mechanism (P for trend: 0.05). The investigational algorithm showed higher inter-reviewer agreement (Cohen's kappa 0.62 vs 0.47). Conclusions: In patients with scar-related ATs, activation mapping algorithms integrating vector data and best-fit propagation solution may help in identifying the mechanism and the successful site of termination.

His bundle pacing shows similar ventricular electrical activation as sinus: selective and nonselective His pacing indistinguishable

His bundle pacing utilizes the His-Purkinje system to produce more physiological activation compared with traditional pacing therapies, but differences in electrical activation between pacing techniques are not yet quantified in terms of activation pattern. Furthermore, clinicians distinguish between selective and nonselective His pacing, but measurable differences in electrical activation remain to be seen. Hearts isolated from seven dogs were perfused using the Langendorff method. Electrograms were recorded using two 64-electrode basket catheters in the ventricles and a 128-electrode sock situated around the ventricles during sinus rhythm (right atrial pacing), right ventricular (RV) pacing, biventricular cardiac resynchronization therapy (biV-CRT), selective His pacing (selective capture of the His bundle), and nonselective His pacing (capture of nearby myocardium and His bundle). Activation maps were generated from these electrograms. Total activation time (TAT) was measured from the activation maps, and QRS duration was measured from a one-lead pseudo-ECG. Results showed that TAT, QRS duration, and activation sequence were most similar between sinus, selective, and nonselective His pacing. Bland-Altman analyses showed highest levels of similarity between all combinations of sinus, selective, and nonselective His pacing. RV and biV-CRT activation patterns were distinct from sinus and had significantly longer TAT and QRS duration. Cumulative activation graphs were most similar between sinus, selective, and nonselective His pacing. In conclusion, selective pacing and nonselective His bundle pacing are more similar to sinus compared with RV and biV-CRT pacing. Furthermore, selective pacing and nonselective His bundle pacing are not significantly different electrically.NEW & NOTEWORTHY Our high-density epicardial and endocardial electrical mapping study demonstrated that selective pacing and nonselective His bundle pacing are more electrically similar to sinus rhythm compared with right ventricular and biventricular cardiac resynchronization therapy pacing. Furthermore, small differences between selective and nonselective His bundle pacing, specifically a wider QRS in nonselective His pacing, do not translate into significant differences in the global activation pattern.

Cellular Mechanisms of Conscious Processing.

Recent breakthroughs in neurobiology indicate that the time is ripe to understand how cellular-level mechanisms are related to conscious experience. Here, we highlight the biophysical properties of pyramidal cells, which allow them to act as gates that control the evolution of global activation patterns. In conscious states, this cellular mechanism enables complex sustained dynamics within the thalamocortical system, whereas during unconscious states, such signal propagation is prohibited. We suggest that the hallmark of conscious processing is the flexible integration of bottom-up and top-down data streams at the cellular level. This cellular integration mechanism provides the foundation for Dendritic Information Theory, a novel neurobiological theory of consciousness.

Understanding unipolar electrograms and global activation from noninvasive mapping for diagnosing arrhythmias

In the past several decades Electrocardiographic Imaging has been developed, validated, and recently commercialized for clinical use (Medtronic CardioInsight™). The technology noninvasively maps cardiac electrical potentials by combining multi-channel body surface electrocardiograms and patient specific heart-torso geometry. Unlike contact catheter mapping where bipolar electrograms are commonly used, noninvasive mapping is unipolar in nature. While bipolar electrograms reflect local activation time, noninvasive mapping reflects both local and global information. Characterizing arrhythmias using noninvasive mapping requires a different approach than what is used with bipolar mapping during electrophysiological studies. With multiple example cases, this article aims to demonstrate how in-depth analysis of noninvasive electrogram features and global activation patterns can reveal clinically important characteristics of arrhythmias, which may not be evident on the automatically generated maps. These characteristics include transmural location of the ectopic focus, differential locations within structural proximity, engagement of bundle or specific tissue, and substrate properties. The analysis approach involves applying unipolar potential fundamentals and relating electrogram features, global activation with underlying electrophysiology and cardiac anatomy to explain specific mapping phenomenon. If validated, easy-to-use diagnostic criteria or algorithms can be built and automated as product features in the commercial system to facilitate future noninvasive mapping in patients.

Brain activation induced by chronic psychosocial stress in mice

Chronic psychosocial stress is a well-established risk factor for neuropsychiatric diseases. Abnormalities in brain activity have been demonstrated in patients with stress-related disorders. Global brain activation patterns during chronic stress exposure are less well understood but may have strong modifying effects on specific brain circuits and thereby influence development of stress-related pathologies. We determined neural activation induced by chronic social defeat stress, a mouse model of psychosocial stress. To assess chronic activation with an unbiased brain-wide focus we used manganese-enhanced magnetic resonance imaging (MEMRI) and immunohistochemical staining of ∆FOSB, a transcription factor induced by repeated neural activity. One week after 10-day social defeat we observed significantly more activation in several brain regions known to regulate depressive and anxiety-like behaviour, including the prefrontal cortex, bed nucleus of stria terminalis, ventral hippocampus and periaqueductal grey in stressed compared to control mice. We further established that the correlation of ∆FOSB positive cells between specific brain regions was altered following chronic social defeat. Chronic activation of these neural circuits may relate to persistent brain activity changes occurring during chronic psychosocial stress exposure, with potential relevance for the development of anxiety and depression in humans.

P.4.e.006 - Brain activation induced by chronic psychosocial stress in mice

Chronic psychosocial stress is a well-established risk factor for neuropsychiatric diseases. Abnormalities in brain activity have been demonstrated in patients with stress-related disorders. Global brain activation patterns during chronic stress exposure are less well understood but may have strong modifying effects on specific brain circuits and thereby influence development of stress-related pathologies. We determined neural activation induced by chronic social defeat stress, a mouse model of psychosocial stress. To assess chronic activation with an unbiased brain-wide focus we used manganese-enhanced magnetic resonance imaging (MEMRI) and immunohistochemical staining of ∆FOSB, a transcription factor induced by repeated neural activity. One week after 10-day social defeat we observed significantly more activation in several brain regions known to regulate depressive and anxiety-like behaviour, including the prefrontal cortex, bed nucleus of stria terminalis, ventral hippocampus and periaqueductal grey in stressed compared to control mice. We further established that the correlation of ∆FOSB positive cells between specific brain regions was altered following chronic social defeat. Chronic activation of these neural circuits may relate to persistent brain activity changes occurring during chronic psychosocial stress exposure, with potential relevance for the development of anxiety and depression in humans.

Ultra-deep tyrosine phosphoproteomics enabled by a phosphotyrosine superbinder.

We present a new strategy for systematic identification of phosphotyrosine (pTyr) by affinity purification mass spectrometry (AP-MS) using a Src homology 2 (SH2)-domain-derived pTyr superbinder as the affinity reagent. The superbinder allows for markedly deeper coverage of the Tyr phosphoproteome than anti-pTyr antibodies when an optimal amount is used. We identified ∼20,000 distinct phosphotyrosyl peptides and >10,000 pTyr sites, of which 36% were 'novel', from nine human cell lines using the superbinder approach. Tyrosine kinases, SH2 domains and phosphotyrosine phosphatases were preferably phosphorylated, suggesting that the toolkit of kinase signaling is subject to intensive regulation by phosphorylation. Cell-type-specific global kinase activation patterns inferred from label-free quantitation of Tyr phosphorylation guided the design of experiments to inhibit cancer cell proliferation by blocking the highly activated tyrosine kinases. Therefore, the superbinder is a highly efficient and cost-effective alternative to conventional antibodies for systematic and quantitative characterization of the tyrosine phosphoproteome under normal or pathological conditions.

Extracting extensor digitorum communis activation patterns using high-density surface electromyography.

The extensor digitorum communis muscle plays an important role in hand dexterity during object manipulations. This multi-tendinous muscle is believed to be controlled through separate motoneuron pools, thereby forming different compartments that control individual digits. However, due to the complex anatomical variations across individuals and the flexibility of neural control strategies, the spatial activation patterns of the extensor digitorum communis compartments during individual finger extension have not been fully tracked under different task conditions. The objective of this study was to quantify the global spatial activation patterns of the extensor digitorum communis using high-density (7 × 9) surface electromyogram (EMG) recordings. The muscle activation map (based on the root mean square of the EMG) was constructed when subjects performed individual four finger extensions at the metacarpophalangeal joint, at different effort levels and under different finger constraints (static and dynamic). Our results revealed distinct activation patterns during individual finger extensions, especially between index and middle finger extensions, although the activation between ring and little finger extensions showed strong covariance. The activation map was relatively consistent at different muscle contraction levels and for different finger constraint conditions. We also found that distinct activation patterns were more discernible in the proximal–distal direction than in the radial–ulnar direction. The global spatial activation map utilizing surface grid EMG of the extensor digitorum communis muscle provides information for localizing individual compartments of the extensor muscle during finger extensions. This is of potential value for identifying more selective control input for assistive devices. Such information can also provide a basis for understanding hand impairment in individuals with neural disorders.

Influence of short-term unweighing and reloading on running kinetics and muscle activity.

In running, body weight reduction is reported to result in decreased lower limb muscle activity with no change in the global activation pattern (Liebenberg et al. in J Sports Sci 29:207-214). Our study examined the acute effects on running mechanics and lower limb muscle activity of short-term unweighing and reloading conditions while running on a treadmill with a lower body positive pressure (LBPP) device. Eleven healthy males performed two randomized running series of 9 min at preferred speed. Each series included three successive running conditions of 3 min [at 100 % body weight (BW), 60 or 80 % BW, and 100 % BW]. Vertical ground reaction force and center of mass accelerations were analyzed together with surface EMG activity recorded from six major muscles of the left lower limb for the first and last 30 s of each running condition. Effort sensation and mean heart rate were also recorded. In both running series, the unloaded running pattern was characterized by a lower step frequency (due to increased flight time with no change in contact time), lower impact and active force peaks, and also by reduced loading rate and push-off impulse. Amplitude of muscle activity overall decreased, but pre-contact and braking phase extensor muscle activity did not change, whereas it was reduced during the subsequent push-off phase. The combined neuro-mechanical changes suggest that LBPP technology provides runners with an efficient support during the stride. The after-effects recorded after reloading highlight the fact that 3 min of unweighing may be sufficient for updating the running pattern.

Repeated BOLD-fMRI imaging of deep brain stimulation responses in rats.

Functional magnetic resonance imaging (fMRI) provides a picture of the global spatial activation pattern of the brain. Interest is growing regarding the application of fMRI to rodent models to investigate adult brain plasticity. To date, most rodent studies used an electrical forepaw stimulation model to acquire fMRI data, with α-chloralose as the anesthetic. However, α-chloralose is harmful to animals, and not suitable for longitudinal studies. Moreover, peripheral stimulation models enable only a limited number of brain regions to be studied. Processing between peripheral regions and the brain is multisynaptic, and renders interpretation difficult and uncertain. In the present study, we combined the medetomidine-based fMRI protocol (a noninvasive rodent fMRI protocol) with chronic implantation of an MRI-compatible stimulation electrode in the ventroposterior (VP) thalamus to repetitively sample thalamocortical responses in the rat brain. Using this model, we scanned the forebrain responses evoked by the VP stimulation repeatedly of individual rats over 1 week. Cortical BOLD responses were compared between the 2 profiles obtained at day1 and day8. We discovered reproducible frequency- and amplitude-dependent BOLD responses in the ipsilateral somatosensory cortex (S1). The S1 BOLD responses during the 2 sessions were conserved in maximal response amplitude, area size (size ratio from 0.88 to 0.91), and location (overlap ratio from 0.61 to 0.67). The present study provides a long-term chronic brain stimulation protocol for studying the plasticity of specific neural circuits in the rodent brain by BOLD-fMRI.

Deep Brain Stimulation: Are Astrocytes a Key Driver Behind the Scene?

Despite its widespread use, the underlying mechanism of deep brain stimulation (DBS) remains unknown. Once thought to impart a "functional inactivation", there is now increasing evidence showing that DBS actually can both inhibit neurons and activate axons, generating a wide range of effects. This implies that the mechanisms that underlie DBS work not only locally but also at the network level. Therefore, not only may DBS induce membrane or synaptic plastic changes in neurons over a wide network, but it may also trigger cellular and molecular changes in other cells, especially astrocytes, where, together, the glial-neuronal interactions may explain effects that are not clearly rationalized by simple activation/inhibition theories alone. Recent studies suggest that (1) high-frequency stimulation (HFS) activates astrocytes and leads to the release of gliotransmitters that can regulate surrounding neurons at the synapse; (2) activated astrocytes modulate synaptic activity and increase axonal activation; (3) activated astrocytes can signal further astrocytes across large networks, contributing to observed network effects induced by DBS; (4) activated astrocytes can help explain the disparate effects of activation and inhibition induced by HFS at different sites; (5) astrocytes contribute to synaptic plasticity through long-term potentiation (LTP) and depression (LTD), possibly helping to mediate the long-term effects of DBS; and (6) DBS may increase delta-opioid receptor activity in astrcoytes to confer neuroprotection. Together, the plastic changes in these glial-neuronal interactions network-wide likely underlie the range of effects seen, from the variable temporal latencies to observed effect to global activation patterns. This article reviews recent research progress in the literature on how astrocytes play a key role in DBS efficacy.

Three-Dimensional High-Density Bipolar Contact Mapping of Left Atrial Endocardial Activation During Sinus Rhythm in Patients With Atrial Fibrillation

Non-contact array mapping studies have demonstrated the existence of a line of conduction block along the septopulmonary bundle area and the posterior left atrial (LA) roof during sinus rhythm (SR). However, little is known of the global LA activation pattern during SR using a high-density contact bipolar mapping system. High-density contact bipolar isochronal mapping (bipolar mapping sites: 292 [IQR 250-348] points) of the LA was performed during SR with the NavX mapping system in 20 patients with paroxysmal atrial fibrillation (AF) and 11 patients with non-paroxysmal AF. The earliest endocardial breakthrough in the the LA from the right atrium (RA) during SR occurred in the anterosuperior LA (77%) or anterior to the right pulmonary veins (23%), and the breakthrough site did not differ between patients with paroxysmal and non-paroxysmal AF. Regardless of the site of breakthrough, the LA activation pattern was homogeneous, and no line of functional block was observed in any patient. Total LA activation time was significantly longer in non-paroxysmal AF patients than in paroxysmal AF patients (95.1 ± 4.3 ms versus 78.3 ± 3.2 ms, P = 0.0040). Contact-based bipolar LA endocardial activation mapping revealed a homogeneous LA activation pattern during SR, regardless of the between-group difference in activation time and the between-patient difference in sites of earliest LA endocardial breakthrough from the RA.

Migraine changes the brain

Purpose of review This review summarizes key findings of the current literature on functional neuroimaging in migraine and describes how these studies have changed our view of the disorder. Recent findings Recent studies have started not only to investigate the global cerebral activation pattern during migraine attacks, but to address specific aspects of migraine attacks such as photophobia, osmophobia as well as pain perception with the aim of disentangling the underlying mechanisms. There is also more and more evidence that the migraine brain is abnormal even outside of attacks and that repeated attacks are leading to functional and structural alterations in the brain, which may in turn drive the transformation of migraine to its chronic form. Some new results are pinpointing toward a potential role of interesting new brain areas in migraine pathophysiology such as the temporal cortex or the basal ganglia. Summary Neuroimaging studies are beginning to shed light on the mechanisms underlying the development and evolution of migraine and its specific symptoms. Future studies have the potential to also improve our understanding of established and upcoming treatment approaches and to monitor treatment effects in an objective and noninvasive way.

High-resolution fMRI detects neuromodulation of individual brainstem nuclei by electrical tongue stimulation in balance-impaired individuals

High-resolution functional magnetic resonance imaging (fMRI) can be used to precisely identify blood oxygen level dependent (BOLD) activation of small structures within the brainstem not accessible with standard fMRI. A previous study identified a region within the pons exhibiting sustained neuromodulation due to electrical tongue stimulation, but was unable to precisely identify the neuronal structure involved. For this study, high-resolution images of neural activity induced by optic flow were acquired in nine healthy controls and nine individuals with balance dysfunction before and after information-free tongue stimulation. Subjects viewed optic flow videos to activate the structures of interest. Sub-millimeter in-plane voxels of structures within the posterior fossa were acquired using a restricted field of view. Whole-brain functional imaging verified that global activation patterns due to optic flow were consistent with previous studies. Optic flow activated the visual association cortices, the vestibular nuclei, and the superior colliculus, as well as multiple regions within the cerebellum. The anterior cingulate cortex showed decreased activity after stimulation, while a region within the pons had increased post-stimulation activity. These observations suggest the pontine region is the trigeminal nucleus and that tongue stimulation interfaces with the balance-processing network within the pons. This high-resolution imaging allows detection of activity within individual brainstem nuclei not possible using standard resolution imaging.