The Pathobiology of Behavioral Changes in Multiple System Atrophy: An Update

Area of Science:

• Neuroscience
• Neurology
• Psychiatry

Background:

• Behavioral disorders are prevalent in multiple system atrophy (MSA), affecting 30-70% of patients.
• These include anxiety, apathy, attention deficits, compulsive behaviors, and REM sleep behavior disorder (RBD).
• These symptoms are early, pervasive, and may influence disease progression in this synucleinopathy.

Purpose of the Study:

• To explore the poorly understood pathophysiological and biochemical mechanisms underlying behavioral disorders in MSA.
• To investigate the neuroimaging correlates of specific behavioral symptoms in MSA.
• To highlight the need for further research into the pathogenesis of these debilitating comorbidities.

Main Methods:

• Review of existing neuroimaging studies linking specific behavioral changes to brain circuit dysfunction.
• Examination of proposed associations between α-synuclein pathology and anxiety in MSA.
• Analysis of the relationship between REM sleep behavior disorder (RBD) and monoaminergic deficits.

Main Results:

• Neuroimaging implicates cortico-limbic changes in anxiety, prefrontal-subcortical dysfunction in apathy/depression, and basal ganglia/orbito-frontal impairment in compulsive behaviors.
• Anxiety is linked to amygdala α-synuclein pathology; RBD to striatal monoaminergic deficits.
• Mechanisms for other behavioral disorders and their links to non-motor dysfunctions remain largely unknown.

Conclusions:

• Behavioral disorders are significant, early features of multiple system atrophy (MSA) with complex underlying mechanisms.
• Current understanding of pathogenesis is limited, particularly regarding biochemical and functional aspects.
• Further neuroimaging and biochemical studies are essential for developing diagnostic biomarkers and effective treatments for MSA-related behavioral symptoms.