Publications by authors named "Baxter P Rogers"

Background: The interthalamic adhesion (IA) is a midline structure connecting the left and right thalamus that typically develops during the 2 trimester of pregnancy. Missing and smaller IA has been linked to neurodevelopmental disorders, including schizophrenia, and subtle deficits in cognition. However, findings are inconsistent and the association between IA and other anatomical variants linked to atypical brain development in schizophrenia, including incomplete hippocampal inversion (IHI), is unclear.

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Structural brain abnormalities in psychosis are well-replicated but heterogenous posing a barrier to uncovering the pathophysiology, etiology, and treatment of psychosis. To parse neurostructural heterogeneity and assess for the presence of anatomically-derived subtypes, we applied a data-driven method, similarity network fusion (SNF), to structural neuroimaging data in a broad cohort of individuals with psychosis (schizophrenia spectrum disorders (SSD) n=280; bipolar disorder with psychotic features (BD) n=101). SNF identified two transdiagnostic subtypes in psychosis (subtype 1: n=158 SSD, n=75 BD; subtype 2: n=122 SSD, n=26 BD) that exhibited divergent patterns of abnormal cortical surface area and subcortical volumes.

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Background: Negative symptom severity predicts functional outcome and quality of life in people with psychosis. However, negative symptoms are poorly responsive to medication, and existing literature has not converged on their neurobiological basis. Previous work in small schizophrenia samples has observed that lower cerebellar-dorsolateral prefrontal cortex (DLPFC) connectivity is associated with higher negative symptom severity and that increasing cerebellar-DLPFC connectivity with neuromodulation reduces negative symptoms.

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Importance: Persecutory delusions are common, distressing, and difficult to treat. Testing computational neuroscience models of delusions can identify new therapeutic targets.

Objective: To determine whether change in delusion severity is associated with a corresponding change in volatility priors and brain activation estimated during a belief updating task.

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Objective: Epilepsy is a debilitating disorder affecting more than 50 million people worldwide, and one third of patients continue to have seizures despite maximal medical management. If patients' seizures localize to a discrete brain region, termed a seizure onset zone, resection may be curative. Localization is often confirmed with stereotactic electroencephalography; however, this may require patients to stay in the hospital for weeks to capture spontaneous seizures.

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Background: There is evidence for altered interoceptive processing in individuals diagnosed with autism, compared to non-autistic individuals. At a neural level, functional and structural connectivity of interoceptive cortices may differ in autism, though developmental patterns of these differences are unclear as well as how these patterns may vary by subregion within the insular cortex. To better understand the roles of autism, age, and subregion in interoceptive connectivity patterns, we used a cross-sectional approach to examine interoceptive functional connectivity across individuals spanning a wide age range.

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The massa intermedia (MI) is a midline structure connecting the left and right thalamus that typically develops during the 2 trimester of pregnancy. Missing and smaller MI has been linked to neurodevelopmental disorders, including schizophrenia (SZ), and subtle deficits in cognition. However, findings are inconsistent and the association between MI and other anatomical variants linked to atypical brain development in SZ, including incomplete hippocampal inversion (IHI), is unclear.

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Background: Negative symptom severity predicts functional outcome and quality life in people with psychosis. However, negative symptoms are poorly responsive to antipsychotic medication and existing literature has not converged on their neurobiological basis. Previous work in small schizophrenia samples has observed that lower cerebellar-prefrontal connectivity is associated with higher negative symptom severity and demonstrated in a separate neuromodulation experiment that increasing cerebellar-prefrontal connectivity reduced negative symptom severity.

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Background: The magnitudes and patterns of alterations of the white-gray matter (WM-GM) functional connectome in preclinical Alzheimer's disease (AD), and their associations with amyloid and cognition, remain unclear.

Methods: We compared regional WM-GM functional connectivity (FC) and network properties in subjects with preclinical AD (or AD dementia) and controls (total n = 344). Their associations with positron emission tomography AV45-measured amyloid beta (Aβ) load and modified Preclinical Alzheimer Cognitive Composite (mPACC) scores were examined.

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Purpose: Prospective motion correction (PMC) with inductively-coupled wireless NMR markers has been shown to be an effective plug-and-play method for dealing with head motion at 7 Tesla [29,30]. However, technical challenges such as one-to-one identification of three wireless markers, generation of hyper-intense marker artifacts and low marker peak SNR in the navigators has limited the adoption of this technique. The goal of this work is to introduce solutions to overcome these issues and extend this technique to PMC for brain imaging at 3 Tesla.

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Article Synopsis
  • Resting state correlations in BOLD MRI signals from white matter are anisotropic, allowing the use of functional correlation tensors (FCTs) to analyze microstructural changes in these brain areas.
  • This study analyzed FCT characteristics in a large sample of 461 cognitively normal individuals aged 42 to 95, aiming to uncover patterns related to aging and sex differences.
  • Results showed variable changes in FCT metrics with age, with some areas showing decreased correlations and others increased—indicating complex regional aging effects, especially with more significant changes observed in females.
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  • The study explored how functional connectivity relates to seizure outcomes at different times after surgery in patients with temporal lobe epilepsy (TLE), focusing on those who underwent a specific surgical procedure known as selective amygdalohippocampectomy.
  • It compared the brain connectivity of patients who remained seizure-free after surgery to those who experienced seizures again, using resting-state fMRI scans taken pre- and post-surgery.
  • Results showed significant differences in brain network strength in specific areas for seizure-free patients, indicating that increased connectivity over time may contribute to better long-term seizure control.
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  • Gradient nonlinearities in MRI can cause distortion and inaccurate diffusion measurements, making it crucial to correct these issues as scanner technology improves.
  • The authors present a mathematical method to estimate the complete gradient nonlinear field using a minimization problem, applicable whether the true diffusion tensor is known or estimated.
  • The study validates this approach through simulations, showing that it effectively estimates gradient fields, achieving minimal differences between estimated and true diffusion metrics, and operates stably even with varying levels of corruption.
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  • Thalamic abnormalities are linked to schizophrenia and neurodevelopmental disorders, but understanding their development and effects on behavior is challenging due to unknown developmental patterns and individual variations.
  • The study utilized data from the Human Connectome Project to establish normative models of thalamic nuclei volumes across ages, revealing complex age-related changes in these structures.
  • About 18% of individuals with schizophrenia showed significantly smaller thalamic volumes, particularly in the mediodorsal and pulvinar regions, with smaller volumes correlating to worse cognitive function, highlighting the need for personalized approaches in treatment.
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Article Synopsis
  • - The study aimed to analyze behavioral and cognitive changes in patients with temporal lobe epilepsy (TLE) after surgical removal of the seizure focus, specifically looking at how brain network dynamics are affected through a measure called average regional controllability (ARC).
  • - Researchers collected and compared brain imaging data from 27 patients before and after selective amygdalohippocampectomy, focusing on edge-wise and node strength changes in the brain's structural network.
  • - Findings revealed significant postsurgical changes in brain nodes near the resection zone and unexpected alterations in the ipsilateral occipital lobe, indicating that network disconnection from TLE surgery causes extensive effects beyond just the immediate area of resection.
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Background: Imaging investigation of cerebrospinal fluid (CSF) in multiple sclerosis (MS) is understudied. Development of noninvasive methods to detect pathological CSF changes would have a profound effect on MS diagnosis and would offer insight into MS pathophysiology and mechanisms of neurological impairment.

Objective: We propose magnetization transfer (MT) MRI as a tool to detect macromolecular changes in spinal CSF.

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Background: Hippocampal abnormalities are among the most consistent findings in schizophrenia. Numerous studies have reported deficits in hippocampal volume, function, and connectivity in the chronic stage of illness. While hippocampal volume and function deficits are also present in the early stage of illness, there is mixed evidence of both higher and lower functional connectivity.

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Functional MRI (fMRI) of the spinal cord is an expanding area of research with potential to investigate neuronal activity in the central nervous system. We aimed to characterize the functional connectivity features of the human lumbar spinal cord using resting-state fMRI (rs-fMRI) at 3T, using region-based and data-driven analysis approaches. A 3D multi-shot gradient echo resting-state blood oxygenation level dependent-sensitive rs-fMRI protocol was implemented in 26 healthy participants.

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Seasonal variations have long been observed in various aspects of human life. While there is an abundance of research that has characterized seasonality effects in, for example, cognition, mood, and behavior, including studies of underlying biophysical mechanisms, direct measurements of seasonal variations of brain functional activities have not gained wide attention. We have quantified seasonal effects on functional connectivity as derived from MRI scans.

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Prolonged inflammatory expression within the central nervous system (CNS) is recognized by the brain as a molecular signal of "sickness", that has knock-on effects to the blood-brain barrier, brain-spinal barrier, blood-cerebrospinal fluid barrier, neuro-axonal structures, neurotransmitter activity, synaptic plasticity, neuroendocrine function, and resultant systemic symptomatology. It is concurred that the inflammatory process associated with cancer and cancer treatments underline systemic symptoms present in a large portion of survivors, although this concept is largely theoretical from disparate and indirect evidence and/or clinical anecdotal reports. We conducted a proof-of-concept study to link for the first time late non-CNS cancer survivors presenting chronic systemic symptoms and the presence of centralized inflammation, or neuroinflammation, using TSPO-binding PET tracer [ C]-PBR28 to visualize microglial activation.

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Nonlinear gradients impact diffusion weighted MRI by introducing spatial variation in estimated diffusion tensors. Recent studies have shown that increasing signal-to-noise ratios and the use of ultra-strong gradients may lead to clinically significant impacts on analyses due to these nonlinear gradients in microstructural measures. These effects can potentially bias tractography results and cause misinterpretation of data.

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Article Synopsis
  • Existing fMRI analysis tools focus on gray matter and are inadequate for processing WM signals, prompting the development of a new preprocessing pipeline aimed at better analyzing WM BOLD signals in older populations.
  • The new pipeline, which incorporates advanced software and high-performance computing, has shown high reliability with an intraclass correlation coefficient of 0.52 - 0.86, making it a valuable resource for studying functional changes in WM as people age.
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The effects of normal aging on functional connectivity (FC) within various brain networks of gray matter (GM) have been well-documented. However, the age effects on the networks of FC between white matter (WM) and GM, namely WM-GM FC, remains unclear. Evaluating crucial properties, such as global efficiency (GE), for a WM-GM FC network poses a challenge due to the absence of closed triangle paths which are essential for assessing network properties in traditional graph models.

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Background: Functional near-infrared spectroscopy (fNIRS) is a viable non-invasive technique for functional neuroimaging in the cochlear implant (CI) population; however, the effects of acoustic stimulus features on the fNIRS signal have not been thoroughly examined. This study examined the effect of stimulus level on fNIRS responses in adults with normal hearing or bilateral CIs. We hypothesized that fNIRS responses would correlate with both stimulus level and subjective loudness ratings, but that the correlation would be weaker with CIs due to the compression of acoustic input to electric output.

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Epilepsy surgery consists of surgical resection of the epileptic focus and is recommended for patients with drug-resistant focal epilepsy. However, focal brain lesions can lead to effects in distant brain regions. Similarly, the focal resection in temporal lobe epilepsy surgery has been shown to lead to functional changes distant from the resection.

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