Neural Bases of Cognitive Impairments in Post-Traumatic Stress Disorders: A Mini-Review of Functional Magnetic Resonance Imaging Findings.

INTRODUCTION: Post-Traumatic Stress Disorder (PTSD) is often associated with impairments in emotional and cognitive domains. Contrarily to the emotional sphere, neural basis underpinnings to cognitive impairments are still not well known. METHODS: We performed a bibliographic search on PUBMED of all the studies investigating the cognitive impairments in PTSD individuals. We considered only studies that applied cognitive tasks using a functional Magnetic Resonance Imaging technique. The inclusion criteria were met by nine studies. RESULTS: Overall, PTSD individuals reported significant impairments in the dorsolateral prefrontal cortex, anterior cingulate cortex, inferior frontal gyrus, insula, inferior temporal cortex, supplement motor area, and Default Mode Network (DMN). Moreover, abnormal activity was reported in subcortical structures (e.g. hippocampus, amygdala, thalamus) and in the cerebellum. LIMITATIONS: Cognitive functioning was assessed using different cognitive tasks. Potential confounding factors such as age, sex, symptoms intensity, and comorbidities might have influenced the results. CONCLUSION: So far, the evidence reported that PTSD is characterized by cognitive impairments in several domains, such as attention, memory and autonomic arousal, which may be due to selective dysfunctions in brain regions that are part of cortical networks, the limbic system and DMN. However, further studies are needed in order to better assess the role of cognitive impairments in PTSD and to develop more targeted therapeutic approaches.

Brain mitochondrial impairment in early-onset Parkinson's disease with or without PINK1 mutation.

BACKGROUND: PINK1 mutations are likely to affect mitochondrial function. The objective of this study was to study brain mitochondrial function in patients with early-onset Parkinson's disease, with or without PINK1 mutations. METHODS: We investigated brain intracellular pH, mitochondrial activity, and energetics with functional magnetic resonance spectroscopy in patients with early-onset Parkinson's disease with PINK1 mutations (n = 10), early-onset Parkinson's disease without PINK1 mutations (n = 10), and healthy sex- and age-matched subjects (n = 20). We measured peak areas of phosphocreatine and beta adenosine triphosphate. RESULTS: The EOPD- group had normal PCr + ßATP contents at rest (P = NS) and under activation (P = NS), but reduced contents during recovery (P < 0.001). The EOPD+ group had abnormal PCr + ßATP contents at rest (P < 0.001) and during activation (P < 0.001); during recovery, the contents only partially recovered (P < 0.001). Brain intracellular pH alterations were more severe with EOPD+ than with EOPD-. CONCLUSIONS: Brain mitochondrial impairments were similar in early-onset Parkinson's disease without PINK1 mutations and late-onset Parkinson's disease. However, mitochondrial impairments were more severe in early-onset Parkinson's disease with PINK1 mutations. © 2020 International Parkinson and Movement Disorder Society.

In Vivo Mitochondrial Function in Idiopathic and Genetic Parkinson's Disease.

Parkinson's disease (PD) is associated with brain mitochondrial dysfunction. High-energy phosphates (HEPs), which rely on mitochondrial functioning, may be considered potential biomarkers for PD. Phosphorus magnetic resonance spectroscopy (31P-MRS) is a suitable tool to explore in vivo cerebral energetics. We considered 10 31P-MRS studies in order to highlight the main findings about brain energetic compounds in patients affected by idiopathic PD and genetic PD. The studies investigated several brain areas such as frontal lobes, occipital lobes, temporoparietal cortex, visual cortex, midbrain, and basal ganglia. Resting-state studies reported contrasting results showing decreased as well as normal or increased HEPs levels in PD patients. Functional studies revealed abnormal PCr + ßATP levels in PD subjects during the recovery phase and abnormal values at rest, during activation and recovery in one PD subject with PINK1 gene mutation suggesting that mitochondrial machinery is more impaired in PD patients with PINK1 gene mutation. PD is characterized by energetics impairment both in idiopathic PD as well as in genetic PD, suggesting that mitochondrial dysfunction underlies the disease. Studies are still sparse and sometimes contrasting, maybe due to different methodological approaches. Further studies are needed to better assess the role of mitochondria in the PD development.