Inverted U-shape-like functional connectivity alterations in cognitive resting-state networks depending on exercise intensity: An fMRI study.

Acute physical activity influences cognitive performance. However, the relationship between exercise intensity, neural network activity, and cognitive performance remains poorly understood. This study examined the effects of different exercise intensities on resting-state functional connectivity (rsFC) and cognitive performance. Twenty male athletes (27.3 ± 3.6 years) underwent cycling exercises of different intensities (high, low, rest/control) on different days in randomized order. Before and after, subjects performed resting-state functional magnetic resonance imaging and a behavioral Attention Network Test (ANT). Independent component analysis and Linear mixed effects models examined rsFC changes within ten resting-state networks. No significant changes were identified in ANT performance. Resting-state analyses revealed a significant interaction in the Left Frontoparietal Network, driven by a non-significant rsFC increase after low-intensity and a significant rsFC decrease after high-intensity exercise, suggestive of an inverted U-shape relationship between exercise intensity and rsFC. Similar but trend-level rsFC interactions were observed in the Dorsal Attention Network (DAN) and the Cerebellar Basal Ganglia Network. Explorative correlation analysis revealed a significant positive association between rsFC increases in the right superior parietal lobule (part of DAN) and better ANT orienting in the low-intensity condition. Results indicate exercise intensity-dependent subacute rsFC changes in cognition-related networks, but their cognitive-behavioral relevance needs further investigation.

Coherent Structural and Functional Network Changes after Thalamic Lesions in Essential Tremor.

BACKGROUND: Magnetic resonance-guided focused ultrasound of the ventral intermediate nucleus is a novel incisionless ablative treatment for essential tremor (ET). OBJECTIVE: The aim was to study the structural and functional network changes induced by unilateral sonication of the ventral intermediate nucleus in ET. METHODS: Fifteen essential tremor patients (66.2 ± 15.4 years) underwent probabilistic tractography and functional magnetic resonance imaging (MRI) during unilateral postural tremor-eliciting tasks using 3-T MRI before, 1 month (N = 15), and 6 months (N = 10) post unilateral sonication. RESULTS: Tractography identified tract-specific alterations within the dentato-thalamo-cortical tract (DTCT) affected by the unilateral lesion after sonication. Relative to the treated hand, task-evoked activation was significantly reduced in contralateral primary sensorimotor cortex and ipsilateral cerebellar lobules IV/V and VI, and vermis. Dynamic causal modeling revealed a significant decrease in excitatory drive from the cerebellum to the contralateral sensorimotor cortex. CONCLUSIONS: Thalamic lesions induced by sonication induce specific functional network changes within the DTCT, notably reducing excitatory input to ipsilateral sensorimotor cortex in ET. ©[2022] International Parkinson and Movement Disorder Society. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Affective Modulation after High-Intensity Exercise Is Associated with Prolonged Amygdalar-Insular Functional Connectivity Increase.

Acute moderate exercise has been shown to induce prolonged changes in functional connectivity (FC) within affect and reward networks. The influence of different exercise intensities on FC has not yet been explored. Twenty-five male athletes underwent 30 min of "low"- (35% < lactate threshold (LT)) and "high"- (20% > LT) intensity exercise bouts on a treadmill. Resting-state fMRI was acquired at 3 Tesla before and after exercise, together with the Positive and Negative Affect Scale (PANAS). Data of 22 subjects (3 dropouts) were analyzed using the FSL feat pipeline and a seed-to-network-based analysis with the bilateral amygdala as the seed region for determining associated FC changes in the "emotional brain." Data were analyzed using a repeated measures ANOVA. Comparisons between pre- and post-exercise were analyzed using a one-sample t-test, and a paired t-test was used for the comparison between "low" and "high" exercise conditions (nonparametric randomization approach, results reported at p < 0.05). Both exercise interventions induced significant increases in the PANAS positive affect scale. There was a significant interaction effect of amygdalar FC to the right anterior insula, and this amygdalar-insular FC correlated significantly with the PANAS positive affect scale (r = 0.47, p = 0.048) in the "high"-intensity exercise condition. Our findings suggest that mood changes after exercise are associated with prolonged alterations in amygdalar-insular FC and occur in an exercise intensity-dependent manner.

Abnormal Cerebellar Connectivity Patterns in Patients with Parkinson's Disease and Freezing of Gait.

In this study, we aimed to evaluate the importance of cerebellum in freezing of gait (FOG) pathophysiology. Due to the fundamental role of the cerebellum in posture and gait control, we examined cerebellar structural and functional connectivity (FC) in patients with PD and FOG. We recruited 15 PD with FOG (PD-FOG), 16 PD without FOG (PD-nFOG) patients, and 16 healthy subjects (HS). The FOG Questionnaire (FOG-Q) assessed FOG severity. Three tesla-MRI study included resting-state functional MRI, diffusion tensor imaging (DTI), and 3D T1-w images. We located seed regions in the cerebellar locomotor region, fastigial, and dentate nucleus to evaluate their FC. DTI parameters were obtained on the superior, middle, and inferior cerebellar peduncles. Global and lobular cerebellum volumes were also calculated. Cerebellar locomotor and fastigial FC was higher in cerebellar and posterior cortical areas in PD-FOG than in HS. FC of the cerebellar locomotor region with cerebellar areas positively correlated with FOG-Q. Dentate FC was lower in the prefrontal and parieto-occipital cortices in PD-FOG than in HS and in the brainstem, right basal ganglia, and frontal and parieto-occipital cortices than in PD-nFOG. DTI parameters in superior and middle cerebellar peduncles were altered in PD-FOG compared with PD-nFOG and significantly correlated with FOG-Q. There were no differences in cerebellar volumes between PD-FOG and either PD-nFOG or HS. Our results suggest that altered connectivity of the cerebellum contributes to the pathophysiology of FOG. FC of the cerebellar locomotor region and white matter (WM) properties of cerebellar peduncles correlate with FOG severity, supporting the hypothesis that abnormal cerebellar function underlies FOG in PD.

Role of Cerebellar Dentate Functional Connectivity in Balance Deficits in Patients with Multiple Sclerosis.

Purpose To prospectively investigate, by using resting-state functional magnetic resonance (MR) imaging, cerebellar dentate nuclei (DNs) functional connectivity abnormalities in multiple sclerosis (MS) to explore their impact on balance impairment in patients with MS, considering the role of DNs and their projections in maintaining balance, posture, and muscle tone, Materials and Methods All subjects provided written informed consent, and the protocol was approved by the university institutional review board. Twenty-five patients with relapsing-remitting MS and 20 healthy control subjects underwent a 3-T resting-state functional MR imaging and static posturography. The seed-based method was applied to identify the cerebellar DNs resting-state network; first-level and high-level analyses were performed by using software tools. Results Compared with control subjects, patients had worse postural stability and altered patterns of cerebellar DNs connectivity network, with decreased connectivity in caudate nuclei and thalami and increased connectivity in the cerebellum, pons, left amygdala, and orbitofrontal cortices (cluster level, family-wise error corrected, P < .05, z threshold > 2.3). In patients, the decreased connectivity in the left caudate nucleus was related with worse balance performance (cluster level, family-wise error corrected P < .05, z threshold > 1.96) regardless of age, lesion burden, and global clinical disability. Conclusion These results reveal abnormalities of corticocerebellar circuit connectivity in patients with MS as compared with control subjects and suggest that the decreased connectivity between the DN and the left caudate nucleus could play a role in balance impairment in MS. © RSNA, 2017.

Dentate nucleus connectivity in adult patients with multiple sclerosis: functional changes at rest and correlation with clinical features.

BACKGROUND AND OBJECTIVE: The dentate nucleus, which is the largest of the cerebellar nuclei, plays a critical role in movement and cognition. The aim of our study was to assess any changes in dentate functional connectivity (FC) in adult relapsing remitting multiple sclerosis (RR-MS) patients and to investigate possible clinical correlates. MATERIALS AND METHODS: In all, 54 patients and 24 healthy subjects (HS) underwent multimodal magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI), three-dimensional-T1-weighted and resting state (RS) functional images; they also underwent a cognitive evaluation, that is, attention and information processing speed, by means of the Paced Auditory Serial Addition Test (PASAT). Patients were also scored according to Expanded Disability Status Scale (EDSS). RS-MRI data were analysed using FMRIB Software Library (FSL) tools, with the seed-based method to identify dentate FC. RESULTS: When compared with HS, patients exhibited brain atrophy and widespread DTI abnormalities, as well as greater FC between the dentate nucleus and cortical areas, particularly in the frontal and parietal lobes. Within these areas, FC in patients correlated inversely with clinical impairment. Finally, FC correlated inversely with lesion load and microstructural brain damage. CONCLUSION: Our findings indicate that dentate FC at rest is altered in MS patients. Whether these functional changes are induced by the disease and play a compensatory role remains to be established.

Primary motor cortex LTP/LTD-like plasticity in probable corticobasal syndrome.

Whether the primary motor cortex (M1) contributes to the pathophysiology of corticobasal syndrome (CBS) remains unclear. In this study in patients with probable CBS, we tested whether M1 plasticity contributes to the pathophysiology of symptoms in the contralateral "less affected" limb, manifesting only parkinsonism, and in the contralateral "more affected" limb, manifesting parkinsonism plus other motor and nonmotor symptoms. In Experiment 1, we applied intermittent/continuous theta-burst stimulation (iTBS/cTBS) over the M1 contralateral to the less affected limb in 17 patients. In Experiment 2, we applied iTBS/cTBS over the M1 contralateral to the more affected limb in 14 of the 17 patients. We measured iTBS/cTBS-induced plasticity as reflected by motor-evoked potential (MEP) changes. Data were compared with those obtained in 17 healthy subjects (HS). In Experiment 1, TBS over the M1 contralateral to the less affected limb disclosed reduced plasticity in patients than in HS. In Experiment 2, in 5 of 14 patients we recorded abnormally low-amplitude MEPs, preventing the evaluation of plasticity in the M1 contralateral to the more affected limb. In the remaining nine patients, TBS disclosed abnormal plasticity characterized by high intersubject variability. In these nine patients, the response to TBS correlated with specific patients' clinical features. In the present study in patients with probable CBS, we have demonstrated heterogeneous abnormalities of M1 that contribute to the pathophysiology of this condition.

Neuroimaging correlates of blinking abnormalities in patients with progressive supranuclear palsy.

OBJECTIVE: We aimed to identify the possible relationship between blinking abnormalities and neuroimaging changes in patients with progressive supranuclear palsy. METHODS: We studied 18 patients with progressive supranuclear palsy and 13 healthy subjects. Voluntary and spontaneous blinking were recorded using kinematic techniques. Changes in brain structures were detected by T1-weighted magnetic resonance imaging and voxel-based morphometry. We then sought possible correlations between blinking and neuroimaging abnormalities in patients. RESULTS: Kinematic analysis indicated several abnormalities during voluntary blinking and a markedly reduced spontaneous blink rate in patients compared with healthy subjects. Neuroimaging showed gray matter loss in cortical and subcortical structures and lower white matter volume in the brainstem. Gray matter loss in subcortical structures correlated with the prolonged pause duration between the closing and opening phases, during voluntary blinking. CONCLUSIONS: This study provides a more specific insight into the pathophysiological mechanisms underlying blinking abnormalities in progressive supranuclear palsy.

Unraveling Brain Functional Connectivity of encoding and retrieval in the context of education.

Human memory is an enigmatic component of cognition which many researchers have attempted to comprehend. Accumulating studies on functional connectivity see brain as a complex dynamic unit with positively and negatively correlated networks in perfect coherence during a task. We aimed to examine coherence of network connectivity during visual memory encoding and retrieval in the context of education. School Educated (SE) and College Educated (CE) healthy volunteers (n=60) were recruited and assessed for visual encoding and retrieval. Functional connectivity using seed to voxel based connectivity analysis of the posterior cingulate cortex (PCC) was evaluated. We noticed that there were reciprocal dynamic changes in both dorsolateral prefrontal cortex (DLPFC) region and PCC regions during working memory encoding and retrieval. In agreement with the previous studies, there were more positively correlated regions during retrieval compared to encoding. The default mode network (DMN) networks showed greater negative correlations during more attentive task of visual encoding. In tune with the recent studies on cognitive reserve we also found that number of years of education was a significant factor influencing working memory connectivity. SE had higher positive correlation to DLPFC region and lower negative correlation to DMN in comparison with CE during encoding and retrieval.

Fractional amplitude of low-frequency fluctuations associated with µ-opioid and dopamine receptor distributions in the central nervous system after high-intensity exercise bouts.

Introduction: Dopaminergic, opiod and endocannabinoid neurotransmission are thought to play an important role in the neurobiology of acute exercise and, in particular, in mediating positive affective responses and reward processes. Recent evidence indicates that changes in fractional amplitude of low-frequency fluctuations (zfALFF) in resting-state functional MRI (rs-fMRI) may reflect changes in specific neurotransmitter systems as tested by means of spatial correlation analyses. Methods: Here, we investigated this relationship at different exercise intensities in twenty young healthy trained athletes performing low-intensity (LIIE), high-intensity (HIIE) interval exercises, and a control condition on three separate days. Positive And Negative Affect Schedule (PANAS) scores and rs-fMRI were acquired before and after each of the three experimental conditions. Respective zfALFF changes were analyzed using repeated measures ANOVAs. We examined the spatial correspondence of changes in zfALFF before and after training with the available neurotransmitter maps across all voxels and additionally, hypothesis-driven, for neurotransmitter maps implicated in the neurobiology of exercise (dopaminergic, opiodic and endocannabinoid) in specific brain networks associated with "reward" and "emotion." Results: Elevated PANAS Positive Affect was observed after LIIE and HIIE but not after the control condition. HIIE compared to the control condition resulted in differential zfALFF decreases in precuneus, temporo-occipital, midcingulate and frontal regions, thalamus, and cerebellum, whereas differential zfALFF increases were identified in hypothalamus, pituitary, and periaqueductal gray. The spatial alteration patterns in zfALFF during HIIE were positively associated with dopaminergic and µ-opioidergic receptor distributions within the 'reward' network. Discussion: These findings provide new insight into the neurobiology of exercise supporting the importance of reward-related neurotransmission at least during high-intensity physical activity.

Differential modulation of resting-state functional connectivity between amygdala and precuneus after acute physical exertion of varying intensity: indications for a role in affective regulation.

Introduction: Physical activity influences psychological well-being. This study aimed to determine the impact of exercise intensity on psychological well-being and alterations in emotion-related brain functional connectivity (FC). Methods: Twenty young, healthy, trained athletes performed a low- and high-intensity interval exercise (LIIE and HIIE) as well as a control condition in a within-subject crossover design. Before and after each condition, Positive And Negative Affect Scale (PANAS) was assessed as well as resting-state functional MRI (rs-fMRI). Voxel-wise FC was examined for bilateral amygdala seed region to whole-brain and emotion-related anatomical regions (e.g., insula, temporal pole, precuneus). Data analyses were performed using linear mixed-effect models with fixed factors condition and time. Results: The PANAS Positive Affect scale showed a significant increase after LIIE and HIIE and a significant reduction in Negative Affect after the control condition. In rs-fMRI, no significant condition-by-time interactions were observed between the amygdala and whole brain. Amygdala-precuneus FC analysis showed an interaction effect, suggesting reduced post-exercise anticorrelation after the control condition, but stable, or even slightly enhanced anticorrelation for the exercise conditions, especially HIIE. Discussion: In conclusion, both LIIE and HIIE had positive effects on mood and concomitant effects on amygdala-precuneus FC, particularly after HIIE. Although no significant correlations were found between amygdala-precuneus FC and PANAS, results should be discussed in the context of affective disorders in whom abnormal amygdala-precuneus FC has been observed.

Hippocampal subfield plasticity is associated with improved spatial memory.

Physical exercise studies are generally underrepresented in young adulthood. Seventeen subjects were randomized into an intervention group (24.2 ± 3.9 years; 3 trainings/week) and 10 subjects into a passive control group (23.7 ± 4.2 years), over a duration of 6 months. Every two months, performance diagnostics, computerized spatial memory tests, and 3 Tesla magnetic resonance imaging were conducted. Here we find that the intervention group, compared to controls, showed increased cardiorespiratory fitness, spatial memory performance and subregional hippocampal volumes over time. Time-by-condition interactions occurred in right cornu ammonis 4 body and (trend only) dentate gyrus, left hippocampal tail and left subiculum. Increases in spatial memory performance correlated with hippocampal body volume changes and, subregionally, with left subicular volume changes. In conclusion, findings support earlier reports of exercise-induced subregional hippocampal volume changes. Such exercise-related plasticity may not only be of interest for young adults with clinical disorders of hippocampal function, but also for sedentary normal cohorts.

Fronto-striatal alterations correlate with apathy severity in behavioral variant frontotemporal dementia.

Structural and functional changes in cortical and subcortical regions have been reported in behavioral variant frontotemporal dementia (bvFTD), however, a multimodal approach may provide deeper insights into the neural correlates of neuropsychiatric symptoms. In this multicenter study, we measured cortical thickness (CTh) and subcortical volumes to identify structural abnormalities in 37 bvFTD patients, and 37 age- and sex-matched healthy controls. For seed regions with significant structural changes, whole-brain functional connectivity (FC) was examined in a sub-cohort of N = 22 bvFTD and N = 22 matched control subjects to detect complementary alterations in brain network organization. To explore the functional significance of the observed structural and functional deviations, correlations with clinical and neuropsychological outcomes were tested where available. Significantly decreased CTh was observed in the bvFTD group in caudal middle frontal gyrus, left pars opercularis, bilateral superior frontal and bilateral middle temporal gyrus along with subcortical volume reductions in bilateral basal ganglia, thalamus, hippocampus, and amygdala. Resting-state functional magnetic resonance imaging showed decreased FC in bvFTD between: dorsal striatum and left caudal middle frontal gyrus; putamen and fronto-parietal regions; pallidum and cerebellum. Conversely, bvFTD showed increased FC between: left middle temporal gyrus and paracingulate gyrus; caudate nucleus and insula; amygdala and parahippocampal gyrus. Additionally, cortical thickness in caudal, lateral and superior frontal regions as well as caudate nucleus volume correlated negatively with apathy severity scores of the Neuropsychiatry Inventory Questionnaire. In conclusion, multimodal structural and functional imaging indicates that fronto-striatal regions have a considerable influence on the severity of apathy in bvFTD.

Independent and additive contribution of white matter hyperintensities and Alzheimer's disease pathology to basal forebrain cholinergic system degeneration.

OBJECTIVES: Degeneration of the cholinergic basal forebrain nuclei (CBFN) system has been studied extensively in Alzheimer's disease (AD). White matter hyperintensities are a hallmark of aging as well as a common co-morbidity of AD, but their contribution to CBFN degeneration has remained unclear. Therefore, we explored the influence of white matter hyperintensities within cholinergic subcortical-cortical projection pathways on CBFN volumes and regional gray matter volumes in AD and age- and gender-matched controls. METHODS: We analyzed magnetic resonance images (MRI) from 42 patients with AD and 87 age- and gender-matched control subjects. We assessed the white matter hyperintensity burden within the cholinergic projection pathways using the Cholinergic Pathways Hyperintensities Scale (CHIPS), and applied probabilistic anatomical maps for the analysis of CBFN volumes, i.e. the Ch1-3 compartment and the Ch4 cell group (nucleus basalis of Meynert), by diffeomorphic anatomical registration using exponentiated lie algebra analysis of voxel-based morphometry. Using multiple linear regression analyses, we explored correlations between regional gray matter volumes and the extent of white matter hyperintensities or CBFN volumes in both groups. RESULTS: In AD, all CBFN volumes were significantly smaller than in controls, and white matter hyperintensity burden within the cholinergic projection pathways was not correlated with CBFN volume. In controls, white matter hyperintensity burden within the cholinergic projection pathways was inversely correlated with CBFN volume when corrected for sex and total intracranial volume, but this correlation was no longer significant after correction for age. Voxel-wise multiple linear regression analyses using threshold-free cluster enhancement revealed that in controls, cholinergic pathway hyperintensities correlated with gray matter loss in perisylvian areas, whereas the were no effects in AD. Moreover, we found that CBFN volumes correlated with distinct regional cortical atrophy patterns in both groups. CONCLUSION: Our results indicate that white matter hyperintensities and AD pathology contribute independently but additively to the degeneration of cholinergic basal forebrain structures. Whereas AD is primarily associated with CBFN volume loss, cholinergic degeneration associated with white matter hyperintensities appears to involve disruption of cholinergic cortical projection fibers with less pronounced effects on CBFN volumes.

MRgFUS of the nucleus ventralis intermedius in essential tremor modulates functional connectivity within the classical tremor network and beyond.

BACKGROUND: Magnetic resonance-guided focused ultrasound (MRgFUS) of the thalamic ventral intermediate nucleus is an incisionless lesional treatment for essential tremor. OBJECTIVE: To examine relationships between tremor severity and functional connectivity in patients with essential tremor and to assess long-term changes in the tremor network after sonication of the ventral intermediate nucleus. METHODS: Twenty-one patients with essential tremor (70.33 ± 11.32 years) were included in the final analysis and underwent resting state functional magnetic resonance imaging at 3 T before and 6 months after treatment. Tremor severity (Fahn-Tolosa-Marin Clinical Rating Scale) was evaluated and functional connectivity was investigated using independent component analysis. RESULTS: MRgFUS of the thalamic ventral intermediate nucleus reduced contralateral tremor effectively. Multiple regression analysis revealed exclusively negative correlations between FC and tremor severity, notably in the right cerebellar lobe VI and the left cerebellar lobe VIIIa (cerebellar network), in the left occipital fusiform gyrus (lateral visual network), the anterior division of the left superior temporal gyrus (fronto-parieto-temporal network), and in the posterior division of the left parahippocampal gyrus and the bilateral lingual gyri (default mode network). Six months after treatment, increased functional connectivity was observed in almost all tremor-associated clusters, except the cluster localized in the left cerebellum. CONCLUSIONS: Our findings suggest that tremor-related activity in essential tremor extends beyond the classical cerebellar network, additionally involving areas related to visual processing. Functional restoration of network activity after sonication of the ventral intermediate nucleus is observed within the classical tremor network (cerebellum) and notably also in visual processing areas.

Whole-brain network transitions within the framework of ignition and transfer entropy following VIM-MRgFUS in essential tremor patients.

Magnetic resonance-guided focused ultrasound (MRgFUS) lesioning of the ventralis intermedius nucleus (VIM) has shown promise in treating drug-refractory essential tremor (ET). It remains unknown whether focal VIM lesions by MRgFUS have broader restorative effects on information flow within the whole-brain network of ET patients. We applied an information-theoretical approach based on intrinsic ignition and the concept of transfer entropy (TE) to assess the spatiotemporal dynamics after VIM-MRgFUS. Eighteen ET patients (mean age 71.44 years) underwent repeated 3T resting-state functional magnetic resonance imaging combined with Clinical Rating Scale for Tremor (CRST) assessments one day before (T0) and one month (T1) and six months (T2) post-MRgFUS, respectively. We observed increased whole brain ignition-driven mean integration (IDMI) at T1 (p < 0.05), along with trend increases at T2. Further, constraining to motor network nodes, we identified significant increases in information-broadcasting (bilateral supplementary motor area (SMA) and left cerebellar lobule III) and information-receiving (right precentral gyrus) at T1. Remarkably, increased information-broadcasting in bilateral SMA was correlated with relative improvement of the CRST in the treated hand. In addition, causal TE-based effective connectivity (EC) at T1 showed an increase from right SMA to left cerebellar lobule crus II and from left cerebellar lobule III to right thalamus. In conclusion, results suggest a change in information transmission capacity in ET after MRgFUS and a shift towards a more integrated functional state with increased levels of global and directional information flow.

Physical Activity Alters Functional Connectivity of Orbitofrontal Cortex Subdivisions in Healthy Young Adults: A Longitudinal fMRI Study.

Physical activity (PA) plays an important role in affect processing. Studies describe the orbitofrontal cortex (OFC) as a major hub for emotion processing and the pathophysiology of affective disorders. Subregions of the OFC show diverse functional connectivity (FC) topographies, but the effect of chronic PA on subregional OFC FC still lacks scientific understanding. Therefore, we aimed at investigating the effects of regular PA on the FC topographies of OFC subregions in healthy individuals within a longitudinal randomized controlled exercise study. Participants (age: 18-35 years) were randomly assigned to either an intervention group (IG; N = 18) or a control group (CG; N = 10). Fitness assessments, mood questionnaires, and resting state functional magnetic resonance imaging (rsfMRI) were performed four times over the duration of 6 months. Using a detailed parcellation of the OFC, we created subregional FC topography maps at each time point and applied a linear mixed model to assess the effects of regular PA. The posterior-lateral right OFC showed a group and time interaction, revealing decreased FC with the left dorsolateral prefrontal cortex in the IG, while FC in the CG increased. Group and time interaction in the anterior-lateral right OFC with the right middle frontal gyrus was driven by increased FC in the IG. The posterior-lateral left OFC showed a group and time interaction based on differential change in FC to the left postcentral gyrus and the right occipital gyrus. This study emphasized regionally distinctive FC changes induced by PA within the lateral OFC territory, while providing aspects for further research.

Automatic planning of MR-guided transcranial focused ultrasound treatment for essential tremor.

Introduction: Transcranial focused ultrasound therapy (tcFUS) offers precise thermal ablation for treating Parkinson's disease and essential tremor. However, the manual fine-tuning of fiber tracking and segmentation required for accurate treatment planning is time-consuming and demands expert knowledge of complex neuroimaging tools. This raises the question of whether a fully automated pipeline is feasible or if manual intervention remains necessary. Methods: We investigate the dependence on fiber tractography algorithms, segmentation approaches, and degrees of automation, specifically for essential tremor therapy planning. For that purpose, we compare an automatic pipeline with a manual approach that requires the manual definition of the target point and is based on FMRIB software library (FSL) and other open-source tools. Results: Our findings demonstrate the high feasibility of automatic fiber tracking and the automated determination of standard treatment coordinates. Employing an automatic fiber tracking approach and deep learning (DL)-supported standard coordinate calculation, we achieve anatomically meaningful results comparable to a manually performed FSL-based pipeline. Individual cases may still exhibit variations, often stemming from differences in region of interest (ROI) segmentation. Notably, the DL-based approach outperforms registration-based methods in producing accurate segmentations. Precise ROI segmentation proves crucial, surpassing the importance of fine-tuning parameters or selecting algorithms. Correct thalamus and red nucleus segmentation play vital roles in ensuring accurate pathway computation. Conclusion: This study highlights the potential for automation in fiber tracking algorithms for tcFUS therapy, but acknowledges the ongoing need for expert verification and integration of anatomical expertise in treatment planning.