Repetitive Transcranial Magnetic Stimulation Improves Hippocampal N-Acetlaspartate Levels and Visual Memory Scores in Alzheimer's Disease.

The latest research into the pathophysiology of Alzheimer's Disease (AD) has included several cognitive deficits related to hippocampal functioning. However, current clinical research fails to consider the full extent of the heterogeneous cognitive spectrum of AD, resulting in a lack of the specific methods required to draw definitive diagnostic and therapeutic conclusions. This also includes in-vivo metabolic measurements for tailoring the diagnostic and therapeutic regimens in humans with AD. Magnetic resonance spectroscopy and repetitive transcranial magnetic stimulation (rTMS) are two novel diagnostic and therapeutic approaches that must be modified to treat AD. In the present study, we aimed to investigate the underlying therapeutic role of rTMS in humans with AD by evaluating the in-vivo hippocampal metabolites before and after rTMS treatment. Based on the data obtained using the fMRI data in our previous study and on the references reported in the literature, in the present study, we decided to use hippocampal NAA data after rTMS stimulation and found a significant increase in NAA levels. To the best of our knowledge, no other study has evaluated the effect of rTMS on hippocampal metabolites in humans with AD.

The functional role of the pulvinar in discriminating between objective and subjective cognitive impairment in major depressive disorder.

INTRODUCTION: Emotionally driven cognitive complaints represent a major diagnostic challenge for clinicians and indicate the importance of objective confirmation of the accuracy of depressive patients' descriptions of their cognitive symptoms. METHODS: We compared cognitive status and structural and functional brain connectivity changes in the pulvinar and hippocampus between patients with total depression and healthy controls. The depressive group was also classified as "amnestic" or "nonamnestic," based on the members' subjective reports concerning their forgetfulness. We then sought to determine whether these patients would differ in terms of objective neuroimaging and cognitive findings. RESULTS: The right pulvinar exhibited altered connectivity in individuals with depression with objective cognitive impairment, a finding which was not apparent in depressive patients with subjective cognitive impairment. DISCUSSION: The pulvinar may play a role in depression-related cognitive impairments. Connectivity network changes may differ between objective and subjective cognitive impairment in depression and may play a role in the increased risk of dementia in patients with depression.

Infection with COVID-19 is no longer a public emergency: But what about degenerative dementia?

Although no longer considered a public health threat, post-COVID cognitive syndrome continues to impact on a considerable proportion of individuals who were infected with COVID-19. Recent studies have also suggested that COVID may be represent a critical risk factor for the development of Alzheimer's disease (AD). We compared 17 COVID patients with 20 controls and evaluated the effects of COVID-19 on general cognitive performance, hippocampal volume, and connections using structural and seed-based connectivity analysis. We showed that COVID patients exhibited considerably worse cognitive functioning and increased hippocampal connectivity supported by the strong correlation between hippocampal connectivity and cognitive scores. Our findings of higher hippocampal connectivity with no observable hippocampal morphological changes even in mild COVID cases may be represent evidence of a prestructural compensatory mechanism for stimulating additional neuronal resources to combat cognitive dysfunction as recently shown for the prodromal stages of degenerative cognitive disorders. Our findings may be also important in light of recent data showing that other viral infections as well as COVID may constitute a critical risk factor for the development of AD. To our knowledge, this is the first study that investigated network differences in COVID patients, with a particular focus on compensatory hippocampal connectivity.

Brain temperature in healthy and diseased conditions: A review on the special implications of MRS for monitoring brain temperature.

Brain temperature determines not only an individual's cognitive functionality but also the prognosis and mortality rates of many brain diseases. More specifically, brain temperature not only changes in response to different physiological events like yawning and stretching, but also plays a significant pathophysiological role in a number of neurological and neuropsychiatric illnesses. Here, we have outlined the function of brain hyperthermia in both diseased and healthy states, focusing particularly on the amyloid beta aggregation in Alzheimer's disease.