Elevated plasma sulfides are associated with cognitive dysfunction and brain atrophy in human Alzheimer's disease and related dementias.

Emerging evidence indicates that vascular stress is an important contributor to the pathophysiology of Alzheimer's disease and related dementias (ADRD). Hydrogen sulfide (H2S) and its metabolites (acid-labile (e.g., iron-sulfur clusters) and bound (e.g., per-, poly-) sulfides) have been shown to modulate both vascular and neuronal homeostasis. We recently reported that elevated plasma sulfides were associated with cognitive dysfunction and measures of microvascular disease in ADRD. Here we extend our previous work to show associations between elevated sulfides and magnetic resonance-based metrics of brain atrophy and white matter integrity. Elevated bound sulfides were associated with decreased grey matter volume, while increased acid labile sulfides were associated with decreased white matter integrity and greater ventricular volume. These findings are consistent with alterations in sulfide metabolism in ADRD which may represent maladaptive responses to oxidative stress.

Cortical oscillatory dysfunction in Parkinson disease during movement activation and inhibition.

Response activation and inhibition are functions fundamental to executive control that are disrupted in Parkinson disease (PD). We used magnetoencephalography to examine event related changes in oscillatory power amplitude, peak latency and frequency in cortical networks subserving these functions and identified abnormalities associated with PD. Participants (N = 18 PD, 18 control) performed a cue/target task that required initiation of an un-cued movement (activation) or inhibition of a cued movement. Reaction times were variable but similar across groups. Task related responses in gamma, alpha, and beta power were found across cortical networks including motor cortex, supplementary and pre- supplementary motor cortex, posterior parietal cortex, prefrontal cortex and anterior cingulate. PD-related changes in power and latency were noted most frequently in the beta band, however, abnormal power and delayed peak latency in the alpha band in the pre-supplementary motor area was suggestive of a compensatory mechanism. PD peak power was delayed in pre-supplementary motor area, motor cortex, and medial frontal gyrus only for activation, which is consistent with deficits in un-cued (as opposed to cued) movement initiation characteristic of PD.

Neuroimaging and Neuropsychological Outcomes Following Clinician-Delivered Cognitive Training for Six Patients With Mild Brain Injury: A Multiple Case Study.

Nearly half of all mild brain injury sufferers experience long-term cognitive impairment, so an important goal in rehabilitation is to address their multiple cognitive deficits to help them return to prior levels of functioning. Cognitive training, or the use of repeated mental exercises to enhance cognition, is one remediation method for brain injury. The primary purpose of this hypothesis-generating pilot study was to explore the statistical and clinical significance of cognitive changes and transfer of training to real-life functioning following 60 h of Brain Booster, a clinician-delivered cognitive training program, for six patients with mild traumatic brain injury (TBI) or non-traumatic acquired brain injury (ABI). The secondary purpose was to explore changes in functional connectivity and neural correlates of cognitive test gains following the training. We used a multiple case study design to document significant changes in cognitive test scores, overall IQ score, and symptom ratings; and we used magnetic resonance imaging (MRI) to explore trends in functional network connectivity and neural correlates of cognitive change. All cognitive test scores showed improvement with statistically significant changes on five of the seven measures (long-term memory, processing speed, reasoning, auditory processing, and overall IQ score). The mean change in IQ score was 20 points, from a mean of 108 to a mean of 128. Five themes emerged from the qualitative data analysis including improvements in cognition, mood, social identity, performance, and Instrumental Activities of Daily Living (IADLs). With MRI, we documented significant region-to-region changes in connectivity following cognitive training including those involving the cerebellum and cerebellar networks. We also found significant correlations between changes in IQ score and change in white matter integrity of bilateral corticospinal tracts (CST) and the left uncinate fasciculus. This study adds to the growing body of literature examining the effects of cognitive training for mild TBI and ABI, and to the collection of research on the benefits of cognitive training in general. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02918994.

Altered Cortico-Limbic Network Connectivity in Parkinsonian Depression: The Effect of Antidepressants.

BACKGROUND: Depression is a common comorbidity of Parkinson's disease (PD); however, the impact of antidepressant status on cortical function in parkinsonian depression is not fully understood. While studies of resting state functional MRI in major depression have shown that antidepressant treatment affects cortical connectivity, data on connectivity and antidepressant status in PD is sparse. OBJECTIVE: We tested the hypothesis that cortico-limbic network (CLN) resting state connectivity is abnormal in antidepressant-treated parkinsonian depression. METHODS: Thirteen antidepressant-treated depressed PD and 47 non-depressed PD participants from the Parkinson's Progression Markers Initiative (PPMI) database were included. Data was collected using 3T Siemens TIM Trio MR scanners and analyzed using SPM and CONN functional connectivity toolbox. Volumetric analysis was also performed using BrainSuite. RESULTS: We found decreased connectivity in the antidepressant-treated depressed PD group when compared to non-depressed PD between the left frontal operculum and bilateral insula, and also reduced connectivity between right orbitofrontal cortex and left temporal fusiform structures. Increased depression scores were associated with decreased insular-frontal opercular connectivity. No ROI volumetric differences were found between groups. CONCLUSION: Given the relationship between depression scores and cortico-limbic connectivity in PD, the abnormal insular-frontal opercular hypoconnectivity in this cohort may be associated with persistent depressive symptoms or antidepressant effects.

Changes in hippocampal metabolites after effective treatment for fibromyalgia: a case study.

BACKGROUND: Fibromyalgia has been associated with disrupted hippocampal brain metabolite ratios by studies using single voxel magnetic resonance spectroscopy (1H-MRS). Exposure to stress is considered a risk factor for the development and exacerbation of fibromyalgia symptoms. Basic science has demonstrated the hippocampus to be exquisitely sensitive to the effects of stressful experience, which results in changes including alterations in metabolite content and frank atrophy. METHODS: This report details the case of a 47-year-old woman with fibromyalgia who was originally found to have a profound depression of the ratio of N-acetylaspartate to creatine in her right hippocampus during participation in a study to assess brain metabolite disturbances in fibromyalgia utilizing single voxel proton magnetic resonance spectroscopy. An individualized treatment strategy was developed based both on physiological abnormalities associated with the disorder and symptoms that characterized the patient's unique clinical profile. RESULTS: Clinical and spectroscopic evaluation following nine months of treatment demonstrated both an improvement in her clinical profile and normalization of the NAA/Cr ratio within her right hippocampus. DISCUSSION: Therapeutic strategies aimed at demonstrable lesions associated with fibromyalgia appear to represent rational targets for pharmacological intervention. The rationale for development of novel pharmacotherapies for this unusual disorder is discussed.

Hippocampal metabolite abnormalities in fibromyalgia: correlation with clinical features.

UNLABELLED: Although the pathology of fibromyalgia is poorly understood, a growing body of evidence suggests involvement of the central nervous system. The hippocampus is a brain center that is sensitive to the effects of stress exposure and has been demonstrated to be affected in a variety of disorders whose onset, like fibromyalgia, are associated with stressful experience. We therefore interrogated the bilateral hippocampus of 16 female fibromyalgia patients in comparison to 8 age- and gender-matched healthy control subjects using single voxel proton magnetic resonance spectroscopy. Our results demonstrate a significant reduction in the ratio of N-acetylaspartate to creatine (NAA/Cr) in fibromyalgia patients versus matched control subjects specifically in the right temporal lobe from a voxel centered on the right hippocampus (patient vs control, mean +/- standard deviation: 1.20 +/- 0.13 vs 1.34 +/- 0.10, P = .03). Moreover, correlation analysis demonstrated a significant negative correlation between patient scores on the Fibromyalgia Impact Questionnaire and NAA/Cr ratio within the right hippocampus (Spearman rank correlation, rho = -0.681, P = .018). Our results indicate that fibromyalgia is associated with brain metabolite abnormalities within the right hippocampus that correlate with patient symptoms. PERSPECTIVE: We have demonstrated an abnormality in hippocampal brain metabolites in premenopausal female fibromyalgia patients with no psychiatric comorbidity. A significant negative correlation between patient subjective experience of symptoms and a reduced NAA/Cr ratio suggests a role for hippocampal pathology in fibromyalgia.