198 | Role of the Mesencephalic Locomotor Region in gait disorders associated with Parkinson’s disease

Disorders of the Nervous System

Author: Joaquín Alejo Quintana | Email: quintana.joaquin.alejo@gmail.com

Joaquín Alejo Quintana , Leonardo Molano Ramírez , Jose Ricardo Lobera , María Soledad Espósito

1° Neurobiology of Movement, Medical Physics Department, Atomic Centre of Bariloche

Locomotion is a fundamental behavior for animals, allowing them to move and interact with their environment. It requires the correct functioning of local circuits in the spinal cord and supraspinal structures responsible for the selection of motor programs, among which the mesencephalic locomotor region (MLR) stands out. The detailed study of these structures and the circuits in which they are embedded is essential to comprehend the etiology of certain neurodegenerative syndromes that impair motor capacity. For example, Parkinson’s disease (PD) is characterized by a plethora of highly debilitating motor and non-motor symptoms, and while some of them are relieved by the administration of dopamine derivatives, others, such as Freezing of Gait (FoG), are not. FoG is defined by the inability to perform a movement despite the intention to do so, causing falls and negatively affecting patients’ quality of life. Here, by globally silencing MLR’s activity and manipulating the activity of its glutamatergic neurons, we study the link between its malfunction and the development of FoG, using a novel behavioral test that provides information on the latency of the onset of locomotion. Our results expand the possibilities for PD symptoms’ study, highlight the importance of the MLR in the control of locomotor behavior and, at the same time, point out the need to delve into the implication of the loss of functionally distinct neuronal subpopulations in this region.