Sensorimotor Cortex Reorganization in Alzheimer's Disease and Metal Dysfunction: A MEG Study

Abstract

Objective. To verify whether systemic biometals dysfunctions affect neurotransmission in living Alzheimer's disease (AD) patients. Methods. We performed a case-control study using magnetoencephalography to detect sensorimotor fields of AD patients, at rest and during median nerve stimulation. We analyzed position and amount of neurons synchronously activated by the stimulation in both hemispheres to investigate the capability of the primary somatosensory cortex to reorganize its circuitry disrupted by the disease. We also assessed systemic levels of copper, ceruloplasmin, non-Cp copper (i.e., copper not bound to ceruloplasmin), peroxides, transferrin, and total antioxidant capacity. Results. Patients' sensorimotor generators appeared spatially shifted, despite no change of latency and strength, while spontaneous activity sources appeared unchanged. Neuronal reorganization was greater in moderately ill patients, while delta activity increased in severe patients. Non-Cp copper was the only biological variable appearing to be associated with patient sensorimotor transmission. Conclusions. Our data strengthen the notion that non-Cp copper, not copper in general, affects neuronal activity in AD. Significance. High plasticity in the disease early stages in regions controlling more commonly used body parts strengthens the notion that physical and cognitive activities are protective factors against progression of dementia.

Unsuspected Involvement of Spinal Cord in Alzheimer Disease

“…The present work is pioneering the investigation of spinal cord alterations in patients with dementia, and in particular with AD, a major neurodegenerative disease known for its profound effects on cognitive functions. The motor/sensorimotor system has already been shown to be affected in AD at various levels in the brain, but nobody has yet investigated the spinal cord (Agosta et al, 2010;Salustri et al, 2013;Castellazzi et al, 2014;Albers et al, 2015;Fu et al, 2018). Here, we have shown that the spinal cord is significantly atrophic in established AD patients.…”

“…As the spinal cord is relaying sensorimotor control signals from the cortex to the peripheral nervous system and vice versa, it is indeed important to assess whether it is affected by atrophy in a disease that is known for its involvement of cognitive domains. Recent indications suggest that there is definitely a sensorimotor network rewiring and that the motor system may even be affected before cognitive functions in AD (Agosta et al, 2010;Salustri et al, 2013;Castellazzi et al, 2014;Albers et al, 2015;Fu et al, 2018). Clinical symptoms of early AD include, amongst others, fine motor impairment, with for example worsening of writing abilities.…”

Predicting individual brain functional connectivity using a Bayesian hierarchical model

“…Compared to the control group, both the MCI and AD disease groups demonstrated weaker positive connectivity within the auditory and sensorimotor networks and also weaker positive connections between these two networks. Some previous studies have found altered activity and connectivity in these two networks that are related to the Alzheimer disease (Agosta et al, 2010; Goll et al 2012; Salustri et al 2013; Terranova et al 2013; Ferreri et al 2016). …”

A combination of physical activity and computerized brain training improves verbal memory and increases cerebral glucose metabolism in the elderly

“…It is tempting to speculate that, as the more susceptible areas of the brain are affected in early dementia, the more resistant areas such as the sensorimotor cortex may provide cognitive reserve and higher neuronal activity following lifestyle interventions. 73 …”