Parkinson’s disease (PD) is a neurodegenerative disorder that affects millions of people worldwide. PD is known to cause tremors, stiffness, and slow movements, but it has also been linked to a number of psychiatric symptoms, including anxiety. While anxiety is a common problem among people with PD, the exact mechanism behind it has remained a mystery. A new study published in the journal Frontiers in Aging Neuroscience has shed light on the potential mechanism behind anxiety in PD.
The study aimed to explore alterations in brain iron deposition in PD patients with anxiety compared to those without anxiety, especially in the fear circuit. The fear circuit is a neural network that is responsible for detecting and processing emotions, such as fear and anxiety. It includes regions such as the amygdala, medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), hippocampus, insula, and striatum. The amygdala plays a crucial role in detecting external threats, transmitting information to other nodes in the fear circuit, and ultimately exporting negative emotions.
The study included 16 PD patients with anxiety, 23 PD patients without anxiety, and 26 healthy elderly controls. Participants underwent neuropsychological assessments and brain magnetic resonance imaging (MRI) examinations. The researchers used two MRI techniques, voxel-based morphometry (VBM) and quantitative susceptibility mapping (QSM), to study brain differences and compare susceptibility changes in the brain tissue among the three groups. The results showed that PD patients with anxiety had increased QSM values in several brain regions, including the mPFC, ACC, hippocampus, precuneus, and angular cortex. These increased QSM values were positively correlated with anxiety scores as measured by the Hamilton Anxiety Rating Scale (HAMA).
The study provides evidence that anxiety in PD is associated with an iron burden in the brain’s fear circuit. This is a groundbreaking discovery and offers a new approach to understanding the mechanism behind anxiety in PD. The findings suggest that excessive iron accumulation in the fear circuit could play a role in the development of anxiety in people with PD. However, the study’s authors emphasize that further research is needed to fully understand the relationship between anxiety and iron deposition in the fear circuit.
This study provides new insight into the potential mechanism behind anxiety in PD and highlights the importance of examining brain iron deposition in people with PD and anxiety. The findings have the potential to lead to new treatments for anxiety in PD, which could improve the quality of life for millions of people affected by this debilitating disease.