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Prof. Dr. Evgeni Ponimaskin Central control of motor functions Dying Lioness (650 B.C.) Central control of motor functions Motorcortex Descending motor pathways Motor neuron nuclei in the spinal cord Subcortical control of motor functions Central control of motor functions Motorcortex Descending motor pathways Motor neuron nuclei in the spinal cord Subcortical control of motor functions Motor activity includes both arranged as well as instictive behaviour and is necessary for the interaction with enviroment - Reflectory - Rhytmic - Voluntary movement Organisation of CNS: Three main axis Rostral-caudal and Dorsal-ventral axis Medial-lateral axis Motor system with 3 levels of control Forebrain - Cortex (motor areas) - Basal ganglia + Thalamus - Cerebellum Brainstem Spinal cord Motor Cortex (BA-6) (BA-4) (BA-1,2,3) (BA-8) (BA-5,7) Functions of motor cortical area Primary motor cortex - responsible for execution of the motor programm Supplementary motor cortex - Programming of complex movements Premotor cortex - Initial phase of movement - Orientataion of the body toward the target - Body posturing Functional analysis of cortex Wilder G. Penfield (1891-1976) „It must be great fun to put question to experimental preparation and have it answered!“ Sites controlling individual muscle Post. Ant. Med. Lat. Layer structure of cortex (layers I – VI) Cytoarchitecture of the primary motor cortex Betz cells project towards the spinal cors Cortical projections Three main projection systems: - Commisural - Associative - Efferent app.106 Fasern 30% of Neurons in Area 4 Motor Efferences 30% of Neurons in Area 6 40% of Neurons in Areae 1,2,3 1 = striatal und thalamic tracts 2 = cortico-rubral tracts 3 = cortico-pontin tracts 4 = cortico-reticlar tracts 7 = cortico-spinal lateral tract 8 = cortico-spinal ventral tract Cortical efferent projections Tractus corticospinalis ventralis Body posturing and balance Tractus corticospinalis lateralis voluntary motor function Motor system with 3 levels of control Forebrain - Cortex (motor areas) - Basal ganglia + Thalamus - Cerebellum Brainstem Spinal cord Efferent projection of brainstem Body posturing and balance Goal-directed limb movement Motor system with 3 levels of control Forebrain - Cortex (motor areas) - Basal ganglia + Thalamus - Cerebellum Brainstem Spinal cord Functions of different spinal cord segments Spinal cord Somato-sensory afferences Sensory neurons efferent and afferent fibers Interneurone Motoneurons Motor efferences Motoneurons within the spinal cord Extremitäten Somatotopic organization of motoneurons within a spinal cord • Proximal muscles: medial part of anterior horn • Distal muscles : lateraler part of anterior horn Central control of motor functions Tractus corticospinalis lateralis Tractus corticospinalis lateralis Tractus corticospinalis ventralis + Tractus corticospinalis ventralis Lateral white matter • Goal-directed limb movement Medial white matter: • Body posturing and balance Basal ganglia and thalamus Circuits within basal ganglia and thalamus input Internal circuits output Cerebellum Control of motor functions Central motor descending projections Movement requires coordinated activity of all components of the motor system!
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