Corrigendum: A structural connectivity atlas of limbic brainstem nuclei.

[This corrects the article DOI: 10.3389/fnimg.2022.1009399.].

Functional MRI Lateralization [M1] of dlPFC and Implications for Transcranial Magnetic Stimulation (TMS) Targeting.

The present study investigates a potential method of optimizing effective strategies for the functional lateralization of the dorsolateral prefrontal cortex (dlPFC) while in a scanner. Effective hemisphere lateralization of the dlPFC is crucial for lowering the functional risks connected to specific interventions (such as neurosurgery and transcranial magnetic stimulation (TMS), as well as increasing the effectiveness of a given intervention by figuring out the optimal location. This task combines elements of creative problem solving, executive decision making based on an internal rule set, and working memory. A retrospective analysis was performed on a total of 58 unique participants (34 males, 24 females, Mage = 42.93 years, SDage = 16.38). Of these participants, 47 were classified as right-handed, 7 were classified as left-handed, and 4 were classified as ambidextrous, according to the Edinburgh Handedness Inventory. The imaging data were qualitatively judged by two trained, blinded investigators (neurologist and neuropsychologist) for dominant handedness (primary motor cortex) and dominant dorsolateral prefrontal cortex (dlPFC). The results demonstrated that 21.4% of right-handed individuals showed a dominant dlPFC localized to the right hemisphere rather than the assumed left, and 16.7% of left-handers were dominant in their left hemisphere. The task completed in the scanner might be an efficient method for localizing a potential dlPFC target for the purpose of brain stimulation (e.g., TMS), though further study replications are needed to extend and validate these findings.

Transcranial focused ultrasound selectively increases perfusion and modulates functional connectivity of deep brain regions in humans.

Background: Low intensity, transcranial focused ultrasound (tFUS) is a re-emerging brain stimulation technique with the unique capability of reaching deep brain structures non-invasively. Objective/Hypothesis: We sought to demonstrate that tFUS can selectively and accurately target and modulate deep brain structures in humans important for emotional functioning as well as learning and memory. We hypothesized that tFUS would result in significant longitudinal changes in perfusion in the targeted brain region as well as selective modulation of BOLD activity and BOLD-based functional connectivity of the target region. Methods: In this study, we collected MRI before, simultaneously during, and after tFUS of two deep brain structures on different days in sixteen healthy adults each serving as their own control. Using longitudinal arterial spin labeling (ASL) MRI and simultaneous blood oxygen level dependent (BOLD) functional MRI, we found changes in cerebral perfusion, regional brain activity and functional connectivity specific to the targeted regions of the amygdala and entorhinal cortex (ErC). Results: tFUS selectively increased perfusion in the targeted brain region and not in the contralateral homolog or either bilateral control region. Additionally, tFUS directly affected BOLD activity in a target specific fashion without engaging auditory cortex in any analysis. Finally, tFUS resulted in selective modulation of the targeted functional network connectivity. Conclusion: We demonstrate that tFUS can selectively modulate perfusion, neural activity and connectivity in deep brain structures and connected networks. Lack of auditory cortex findings suggests that the mechanism of tFUS action is not due to auditory or acoustic startle response but rather a direct neuromodulatory process. Our findings suggest that tFUS has the potential for future application as a novel therapy in a wide range of neurological and psychiatric disorders associated with subcortical pathology.

Connectivity-based parcellation of the amygdala and identification of its main white matter connections.

The amygdala plays a role in emotion, learning, and memory and has been implicated in behavioral disorders. Better understanding of the amygdala circuitry is crucial to develop new therapies for these disorders. We used data from 200 healthy-subjects from the human connectome project. Using probabilistic tractography, we created population statistical maps of amygdala connectivity to brain regions involved in limbic, associative, memory, and reward circuits. Based on the amygdala connectivity with these regions, we applied k-means clustering to parcellate the amygdala into three clusters. The resultant clusters were averaged across all subjects and the main white-matter pathways of the amygdala from each averaged cluster were generated. Amygdala parcellation into three clusters showed a medial-to-lateral pattern. The medial cluster corresponded with the centromedial and cortical nuclei, the basal cluster with the basal nuclei and the lateral cluster with the lateral nuclei. The connectivity analysis revealed different white-matter pathways consistent with the anatomy of the amygdala circuit. This in vivo connectivity-based parcellation of the amygdala delineates three clusters of the amygdala in a mediolateral pattern based on its connectivity with brain areas involved in cognition, memory, emotion, and reward. The human amygdala circuit presented in this work provides the first step for personalized amygdala circuit mapping for patients with behavioral disorders.

Noninvasive Delivery of Biologicals to the Brain.

In the past, psychotherapy and neuropharmacological approaches have been the most common treatments for disordered thoughts, moods, and behaviors. One new path of brain therapeutics is in the deployment of noninvasive approaches designed to reprogram brain function at the cellular level. Treatment at the cellular level may be considered for a wide array of disorders, ranging from mood disorders to neurodegenerative disorders. Brain-targeted biological therapy may provide minimally invasive and accurate delivery of treatment. The present article discusses the hurdles and advances that characterize the pathway to this goal.

Ultrasound as a Neurotherapeutic: A Circuit- and System-Based Interrogation.

Focused ultrasound is a novel brain stimulation modality that combines the noninvasiveness of repetitive transcranial magnetic stimulation and the precision of deep brain stimulation. In this review, the authors examine low-intensity focused ultrasound for brain mapping and neuromodulation. They also discuss high-intensity focused ultrasound, which is used for incisionless surgeries, such as capsulotomies for obsessive-compulsive disorder. Future potential applications of focused ultrasound are also presented.

A Systematic Approach to Neuropsychiatric Intervention: Functional Neuroanatomy Underlying Symptom Domains as Targets for Treatment.

An ever-growing population experiences a wide range of psychopathologies, and there is now more than ever a need for clear differential diagnoses between disorders. Furthering this need is the fact that many psychological, psychiatric, and neurological disorders have overlapping features. Functional neuroimaging has been shown to differentiate not only between the function of different brain structures but also between the roles of these structures in functional networks. The aim of this article is to aid in the goal of parsing out disorders on the basis of specific symptom domains by utilizing the most recent literature on functional networks. Current literature on the role of brain networks in relation to different psychopathological symptom domains is examined and corresponding circuit-based therapies that have been or may be used to treat them are discussed. Research on depression, obsession and compulsions, addiction, anxiety, and psychosis is reviewed. An understanding of networks and their specific dysfunctions opens the possibility of a new form of psychopathological treatment.

The Role of the Insula in Classical and Dissociative PTSD: A Double Case Study.

Two service members were diagnosed with PTSD due to military trauma exposure. One presented with the classical manifestation; the other presented with the dissociative subtype. A statistical map revealed anterior localization of insula connectivity in the classical PTSD patient and posterior localization in the dissociative PTSD patient. These differences suggest that dissociative PTSD may be identified, understood, and treated as a disorder related to increased posterior insula connectivity. This double case study provides preliminary evidence for a concrete neuroanatomical discrepancy between insula function in classical and dissociative PTSD that may help explain the emergence of different coping strategies.

Intraindividual variability in neuropsychological performance predicts longitudinal cortical volume loss in early Parkinson's disease.

OBJECTIVE: Cognitive impairment is common among individuals with Parkinson's disease (PD). Intraindividual variability (IIV) is a measure of variability across multiple tasks of cognitive functioning. Due to the limited amount of research, particularly among individuals with PD, IIV has been an underutilized metric of cognitive functioning both in research and clinical practice. Previous research demonstrated that individuals with PD have greater variability in cognitive performance relative to controls, and that IIV is predictive of future cognitive impairments. The aim of this study is to investigate the association between baseline IIV and change in cortical and subcortical volumes among individuals with PD. METHOD: The present study used data from 80 newly diagnosed PD patients who were part of a longitudinal cohort study (Parkinson progression marker initiative [PPMI]). Participants completed neuropsychological measures and underwent T1 structural magnetic resonance imaging (MRI) at baseline and the first annual follow-up. Neuropsychological tests assessed attention, processing speed, visuospatial functioning, verbal fluency learning, and memory. T1 scans were processed using standard Freesurfer protocols for extraction of regional volumes. RESULTS: Greater IIV at baseline was predictive of change in cortical volume in posterior temporal/parietal regions over the 1-year period. Baseline IIV predicted cortical volume changes above and beyond the main effect of motor severity and the baseline statistical mean/global cognition score. CONCLUSION: Our results provide initial evidence that IIV is a marker of longitudinal cortical volume loss. Evidence is building that IIV is a sensitive marker of cognitive impairment and the underlying neurodegeneration among individuals with PD. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Safety and Efficacy of Platelet Rich Plasma for Treatment of Lumbar Discogenic Pain: A Prospective, Multicenter, Randomized, Double-blind Study.

BACKGROUND: Interventions for chronic discogenic spine pain are currently insufficient in lowering individual patient suffering and global disease burden. A 2016 study of platelet rich plasma (PRP) for chronic discogenic pain previously demonstrated clinically significant response among active group patients compared with controls. OBJECTIVES: To replicate the previous research to move this intervention forward as a viable option for patient care. STUDY DESIGN: A double-blind, randomized, placebo-controlled study. SETTING: Multicenter private practices. METHODS: Twenty-six (12 men, 14 women) human patients, ages 25 to 71 with a diagnosis of chronic lumbar discogenic pain, were randomly assigned to active (PRP) or control (saline) groups in a ratio of 2 active to 1 control. Baseline and follow-up Oswestry Disability Index and Numeric Pain Rating Scale questionnaires were obtained to track patient outcomes at 8 weeks postoperatively. RESULTS: Within group assessment showed clinically significant improvement in 17% of PRP patients and clinically significant decline in 5% (1 patient) of the active group. Clinically significant improvement was seen in 13% of placebo group patients and no placebo patients had clinically significant decline secondary to the procedure. LIMITATIONS: Possible explanations may include a range of factors including differences in patient demographics, outcome-measure sensitivity, or misalignment of statistical analyses. CONCLUSIONS: These findings are markedly different than the highly promising results of the 2016 PRP study. This study posits necessary caution for researchers who wish to administer PRP for therapeutic benefit and may ultimately point to necessary redirection of interventional research for discogenic pain populations.

A structural connectivity atlas of limbic brainstem nuclei.

Background: Understanding the structural connectivity of key brainstem nuclei with limbic cortical regions is essential to the development of therapeutic neuromodulation for depression, chronic pain, addiction, anxiety and movement disorders. Several brainstem nuclei have been identified as the primary central nervous system (CNS) source of important monoaminergic ascending fibers including the noradrenergic locus coeruleus, serotonergic dorsal raphe nucleus, and dopaminergic ventral tegmental area. However, due to practical challenges to their study, there is limited data regarding their in vivo anatomic connectivity in humans. Objective: To evaluate the structural connectivity of the following brainstem nuclei with limbic cortical areas: locus coeruleus, ventral tegmental area, periaqueductal grey, dorsal raphe nucleus, and nucleus tractus solitarius. Additionally, to develop a group average atlas of these limbic brainstem structures to facilitate future analyses. Methods: Each nucleus was manually masked from 197 Human Connectome Project (HCP) structural MRI images using FSL software. Probabilistic tractography was performed using FSL's FMRIB Diffusion Toolbox. Connectivity with limbic cortical regions was calculated and compared between brainstem nuclei. Results were aggregated to produce a freely available MNI structural atlas of limbic brainstem structures. Results: A general trend was observed for a high probability of connectivity to the amygdala, hippocampus and DLPFC with relatively lower connectivity to the orbitofrontal cortex, NAc, hippocampus and insula. The locus coeruleus and nucleus tractus solitarius demonstrated significantly greater connectivity to the DLPFC than amygdala while the periaqueductal grey, dorsal raphe nucleus, and ventral tegmental area did not demonstrate a significant difference between these two structures. Conclusion: Monoaminergic and other modulatory nuclei in the brainstem project widely to cortical limbic regions. We describe the structural connectivity across the several key brainstem nuclei theorized to influence emotion, reward, and cognitive functions. An increased understanding of the anatomic basis of the brainstem's role in emotion and other reward-related processing will support targeted neuromodulatary therapies aimed at alleviating the symptoms of neuropsychiatric disorders.

Transcranial Infrared Laser Stimulation for the Treatment of Traumatic Brain Injury: A Case Series.

Introduction: This study intended to evaluate the safety and possible therapeutic effect of transcranial infrared laser stimulation (TILS) based on photobiomodulation (PBM) among patients with traumatic brain injury (TBI). Methods: Eleven participants who were diagnosed with TBI after full neurological examination and MRI evaluation by a board-certified neurologist completed five to eight 20-minute TILS sessions using the Cytonsys CytonPro-5000 apparatus (pilot laser control, focused wavelength of 1064 nm, maximum output power of 10W, maximum optical power density of 500 mW/cm2, effective area 4.5 cm2 in diameter). Per TILS session, participants underwent a laser dose of 250 mW/cm2 continuous laser wave to each hemisphere using predetermined patient-specific coordinates. Structural imaging was used to neuronavigate individual treatment targets in the frontal cortex (Brodmann area 10). The primary safety measure for this study was the occurrence of adverse events (AEs) or serious adverse events (SAEs). The primary efficacy outcome measure was the participant-rated global rating of change (GRC) post-intervention. Secondary outcome measures included a battery of neuropsychological testing and mood questionnaires done both pre- and post-intervention. Results: All patients enrolled in this study protocol were able to tolerate the study procedures without any AEs or SAEs. Nine out of eleven participants had clinically significant improvements in GRC score (≥ +2). Neuropsychological testing and mood questionnaire outcomes also suggested a positive therapeutic effect. Conclusion: This study provides preliminary evidence supporting the safety and potential efficacy of TILS as a non-invasive clinical intervention for individuals with TBI.

Neuroanatomical differences in the memory systems of intellectual giftedness and typical development.

INTRODUCTION: Studying neuro-structural markers of intellectual giftedness (IG) will inform scientific understanding of the processes helping children excel academically. METHODS: Structural and diffusion-weighted MRI was used to compare regional brain shape and connectivity of 12 children with average to high average IQ and 18 IG children, defined as having IQ greater than 145. RESULTS: IG had larger subcortical structures and more robust white matter microstructural organization between those structures in regions associated with explicit memory. TD had more connected, larger subcortical structures in regions associated with implicit memory. CONCLUSIONS: It was found that the memory systems within brains of children with exceptional intellectual abilities are differently sized and connected compared to the brains of typically developing children. These different neurodevelopmental trajectories suggest different learning strategies. A spectrum of intelligence types is envisioned, facilitated by different ratios of implicit and explicit system, which was validated using a large external dataset.

Translating state-of-the-art brain magnetic resonance imaging (MRI) techniques into clinical practice: multimodal MRI differentiates dementia subtypes in a traditional clinical setting.

BACKGROUND: This study sought to validate the clinical utility of multimodal magnetic resonance imaging (MRI) techniques in the assessment of neurodegenerative disorders. We intended to demonstrate that advanced neuroimaging techniques commonly used in research can effectively be employed in clinical practice to accurately differentiate heathy aging and dementia subtypes. METHODS: Twenty patients with dementia of the Alzheimer's type (DAT) and 18 patients with Parkinson's disease dementia (PDD) were identified using gold-standard techniques. Twenty-three healthy, age and sex matched control participants were also recruited. All participants underwent multimodal MRI including T1 structural, diffusion tensor imaging (DTI), arterial spin labeling (ASL), and magnetic resonance spectroscopy (MRS). MRI modalities were evaluated by trained neuroimaging readers and were separately assessed using cross-validated, iterative discriminant function analyses with subsequent feature reduction techniques. In this way, each modality was evaluated for its ability to differentiate patients with dementia from healthy controls as well as to differentiate dementia subtypes. RESULTS: Following individual and group feature reduction, each of the multimodal MRI metrics except MRS successfully differentiated healthy aging from dementia and also demonstrated distinct dementia subtypes. Using the following ten metrics, excellent separation (95.5% accuracy, 92.3% sensitivity; 100.0% specificity) was achieved between healthy aging and neurodegenerative conditions: volume of the left frontal pole, left occipital pole, right posterior superior temporal gyrus, left posterior cingulate gyrus, right planum temporale; perfusion of the left hippocampus and left occipital lobe; fractional anisotropy (FA) of the forceps major and bilateral anterior thalamic radiation. Using volume of the left frontal pole, right posterior superior temporal gyrus, left posterior cingulate gyrus, perfusion of the left hippocampus and left occipital lobe; FA of the forceps major and bilateral anterior thalamic radiation, neurodegenerative subtypes were accurately differentiated as well (87.8% accuracy, 95.2% sensitivity; 85.0% specificity). CONCLUSIONS: Regional volumetrics, DTI metrics, and ASL successfully differentiated dementia patients from controls with sufficient sensitivity to differentiate dementia subtypes. Similarly, feature reduction results suggest that advanced analyses can meaningfully identify brain regions with the most positive predictive value and discriminant validity. Together, these advanced neuroimaging techniques can contribute significantly to diagnosis and treatment planning for individual patients.

Treatment of Dementia With Bosutinib: An Open-Label Study of a Tyrosine Kinase Inhibitor.

OBJECTIVE: The pursuit of an effective therapeutic intervention for dementia has inspired interest in the class of medications known as tyrosine kinase inhibitors such as bosutinib. METHODS: Thirty-one patients with probable Alzheimer dementia or Parkinson spectrum disorder with dementia completed 12 months of bosutinib therapy and an additional 12 months of follow-up. The Clinical Dementia Rating scale (as estimated by the Quick Dementia Rating System [QDRS]) was the primary cognitive status outcome measure. Secondary outcome measures included the Repeatable Battery Assessment of Neuropsychological Status (RBANS) and the Montreal Cognitive Assessment. Cox regression methods were used to compare results with population-based estimates of cognitive decline. RESULTS: The present article reports on cognitive outcomes obtained at 12 months for 31 participants and up to 24 months for a 16-participant subset. Safety and tolerability of bosutinib were confirmed among the study population (Mage = 73.7 years, SDage = 14 years). Bosutinib was associated with less worsening in Clinical Dementia Rating (CDR) scores (hazard ratio = -0.62, p < 0.001, 95% confidence interval [CI]: -1.02 to -0.30) and less decline in RBANS performance (hazard ratio = -3.42, p < 0.001, 95% CI: -3.59 to -3.72) during the year of treatment than population-based estimates of decline. In the 24-month follow-up, wherein 16 patients were observed after 1 year postintervention, 31.2% of participants exhibited worsened CDR levels compared with their 12-month performances. CONCLUSIONS: Results support an overall positive outcome after 1 year of bosutinib. Future studies should explore the relationship between tyrosine kinases and neurodegenerative pathology as well as related avenues of treatment.

Safety of focused ultrasound neuromodulation in humans with temporal lobe epilepsy.

OBJECTIVE: Transcranial Focused Ultrasound (tFUS) is a promising new potential neuromodulation tool. However, the safety of tFUS neuromodulation has not yet been assessed adequately. Patients with refractory temporal lobe epilepsy electing to undergo an anterior temporal lobe resection present a unique opportunity to evaluate the safety and efficacy of tFUS neuromodulation. Histological changes in tissue after tFUS can be examined after surgical resection, while further potential safety concerns can be assessed using neuropsychological testing. METHODS: Neuropsychological functions were assessed in eight patients before and after focused ultrasound sonication of the temporal lobe at intensities up to 5760 mW/cm2. Using the BrainSonix Pulsar 1002, tFUS was delivered under MR guidance, using the Siemens Magnetom 3T Prisma scanner. Neuropsychological changes were assessed using various batteries. Histological changes were assessed using hematoxylin and eosin staining, among others. RESULTS: With respect to safety, the histological analysis did not reveal any detectable damage to the tissue, except for one subject for whom the histology findings were inconclusive. In addition, neuropsychological testing did not show any statistically significant changes in any test, except for a slight decrease in performance on one of the tests after tFUS. SIGNIFICANCE: This study supports the hypothesis that low-intensity Transcranial Focused Ultrasound (tFUS) used for neuromodulation of brain circuits at intensities up to 5760 mW/cm2 may be safe for use in human research. However, due to methodological limitations in this study and inconclusive findings, more work is warranted to establish the safety. Future directions include greater number of sonications as well as longer exposure at higher intensity levels to further assess the safety of tFUS for modulation of neuronal circuits.

Brain circuitry underlying the ABC model of anxiety.

Anxiety Disorders are prevalent and often chronic, recurrent conditions that reduce quality of life. The first-line treatments, such as serotonin reuptake inhibitors and cognitive behavioral therapy, leave a significant proportion of patients symptomatic. As psychiatry moves toward targeted circuit-based treatments, there is a need for a theory that unites the phenomenology of anxiety with its underlying neural circuits. The Alarm, Belief, Coping (ABC) theory of anxiety describes how the neural circuits associated with anxiety interact with each other and domains of the anxiety symptoms, both temporally and spatially. The latest advancements in neuroimaging techniques offer the ability to assess these circuits in vivo. Using Neurosynth, a large open-access meta-analytic imaging database, the association between terms related to specific neural circuits was explored within the ABC theory framework. Alarm-related terms were associated with the amygdala, anterior cingulum, insula, and bed nucleus of stria terminalis. Belief-related terms were associated with medial prefrontal cortex, precuneus, bilateral temporal poles, and hippocampus. Coping-related terms were associated with the ventrolateral and dorsolateral prefrontal cortices, basal ganglia, and anterior cingulate. Neural connections underlying the functional neuroanatomy of the ABC model were observed. Additionally, there was considerable interaction and overlap between circuits associated with the symptom domains. Further neuroimaging research is needed to explore the dynamic interaction between the functional domains of the ABC theory. This will pave the way for probing the neuroanatomical underpinnings of anxiety disorders and provide an evidence-based foundation for the development of targeted treatments, such as neuromodulation.