Introduction
The substantia nigra (SN) is an essential structure of the brain that plays a critical role in controlling movement. This opinion article aims to explore the findings presented in the study “Anatomical and functional organization of the human substantia nigra and its connections” published in the journal eLife, highlighting the functional importance of this region and its implications in the neuroscience of movement.
Evidence and Discussion
The substantia nigra is subdivided into two main parts: the pars compact (SNc) and the pars reticulata (SNr). The SNc is known for its dopaminergic cells, the degeneration of which is associated with Parkinson’s disease, while the SNr is crucial for somatosensory integration and movement organization.
Installments and Connectivity:
The research by Zhang et al. (2017) identified a tripartition based on connectivity of the substantia nigra with a limbic, cognitive, and motor organization. The medial part of the SN connects with limbic regions of the striatum and cortex, encoding reward values, while the ventral part connects with associative regions, encoding salience. The lateral part is associated with somatomotor regions, also encoding salience (Zhang et al., 2017).
Impulsivity and Decision Making:
Connectivity within the medial network, which encodes value, is associated with decisional impulsivity, while the ventral network, which encodes salience, is related to motor impulsivity. These findings highlight the anatomical and functional heterogeneity of the substantia nigra and its distinct networks that underpin different aspects of impulsive behavior (Zhang et al., 2017).
Motor Control and Movement Disorders:
The SNr, being the main output structure of the basal ganglia, is involved in somatosensory integration and movement organization. Studies have shown that changes in SNr neuronal activity may be associated with movement disorders, such as those observed in Parkinson’s disease, where there is an increase in the activity of the basal ganglia output nuclei due to hyperactivity of the subthalamic nucleus (Windels & Kiyatkin, 2006).
Conclusion
The substantia nigra plays a multifaceted role in controlling movement, integrating limbic, cognitive, and motor information. Its complex functional organization and distinct connections are fundamental to understanding the mechanisms underlying various impulsive behaviors and movement disorders. Continuous studies on their networks and connectivity are essential for the development of new therapeutic strategies for neurodegenerative diseases such as Parkinson’s.
Reference
ZHANG, Yu; LARCHER, K.; MIŠIĆ, B.; DAGHER, A. Anatomical and functional organization of the human substantia nigra and its connections. eLife, 2017.
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