The movement Sample Clauses

The movement signalling pathways of the brain’s basal ganglia. Signals are grouped into 2 pathways: the movement-generating direct pathway (solid lines) and the movement-inhibiting indirect pathway (dotted lines). Where pathways overlap (for example in the efferent signals from the SNpr and internal globus pallidus), a solid line is used. Signals in green are excitatory, while inhibitory signals are red. SNpc: substantia nigra pars compacta, SNpr: substantia nigra pars reticulata. D1 and D2 refer to the type of dopamine receptors located at the putamen and caudate nucleus respectively. Movement-influencing signals in the basal ganglia can be grouped into 2 pathways: the movement-generating direct pathway and the movement-inhibiting indirect pathway. The direct pathway promotes movement by increasing thalamic-motor cortex signalling via its putamen-mediated disinhibition. On the other hand the indirect pathway dampens thalamic signalling by strengthening the inhibitory signals of the substantia nigra pars reticulata (SNpr) and the internal globus pallidus. The SNpc plays a key role in modulating the strengths of these 2 pathways. Dopamine released by SNpc neurons at D1 receptors promotes activation of the direct pathway at the putamen. At the same time, dopamine also acts upon inhibitory D2 receptors at the caudate nucleus to inhibit the indirect pathway. The end result of dopamine’s dual action is a movement-promoting signal being sent from the thalamus to the motor cortex and onwards to the periphery (Xxxxxx, Xxxxxxxx & Xxxxxx 2000, Xxxxxx et al. 2001). Upon degeneration of the SNpc, the balance between these 2 pathways is disrupted, causing increased thalamic inhibition. In practice, this leads to a lowering of the body’s ability to change conscious thought into movement. In particular, subtle movements, which the SNpc is especially capable of facilitating, become harder to perform, leading to the characteristically rigid movement patterns common in PD patients (Purves et al. 2001). While degeneration of SNpc dopaminergic neurons is the most identifiable cause of PD and, indeed, the key factor of its movement-deteriorating pathology, there is growing evidence to suggest that PD is not simply a disorder affecting this single cell

The movement development and functional cooperation All components shall strive to assist each other to realize their full potential and adopt a policy of constructive complentarity in elaborating a comprehensive development approach.