14 Motor system III Hierarchic organization of motor system http://www.slideshare.net/drpsdeb/presentations Basal ganglia • Corpus striatum – Nucleus caudatus – Putamen • Globus pallidus (Pallidum) – Externum – Internum • Nucleus subthalamicus • Substantia nigra – Pars compacta – Pars reticulata • Thalamic motor nuclei http://www.slideshare.net/CsillaEgri/presentations Basal ganglia • Corpus striatum – Nucleus caudatus – Putamen • Globus pallidus (Pallidum) – Externum – Internum • Nucleus subthalamicus • Substantia nigra – Pars compacta – Pars reticulata • Thalamic motor nuclei http://www.slideshare.net/CsillaEgri/presentations Basal ganglia - inputs Corpus striatum • Connections from all cortical areas with two exceptions – primary visual and primary auditory cortex • The most of connections from – Frontal and parietal association areas – Motor areas http://www.slideshare.net/CsillaEgri/presentations Basal ganglia - inputs Corpus striatum • Connections from all cortical areas with two exceptions – primary visual and primary auditory cortex • The most of connections from – Frontal and parietal association areas – Motor areas http://www.slideshare.net/CsillaEgri/presentations Basal ganglia • Motor control realized by two circuits – Direct pathway • Motor cortex activation – Indirect pathway • Motor cortex inhibition Direct pathway Cortex Corpus striatum Globus pallidus internus (Gpi) Thalamus Cortex http://www.slideshare.net/drpsdeb/presentations Direct pathway http://www.slideshare.net/drpsdeb/presentations • Thalamic motor nuclei activate motor cortex • Tonic inhibitions of thalamic motor nuclei by GPi • Activated corpus striatum transiently inhibits Gpi, resulting in transient disinhibition of thalamic motor nuclei Direct pathway http://www.slideshare.net/drpsdeb/presentations • Thalamic motor nuclei activate motor cortex • Tonic inhibitions of thalamic motor nuclei by GPi • Activated corpus striatum transiently inhibits Gpi, resulting in transient disinhibition of thalamic motor nuclei Direct pathway • Thalamic motor nuclei activate motor cortex • Tonic inhibitions of thalamic motor nuclei by GPi • Activated corpus striatum transiently inhibits Gpi, resulting in transient disinhibition of thalamic motor nuclei http://www.slideshare.net/drpsdeb/presentations Indirect pathway Cortex Corpus striatum Globus pallidus externus (GPe) GPiNucleus subthalamicus (NS) http://www.slideshare.net/drpsdeb/presentations • NS activates GPi • GPe tonically inhibits NS • Corpus striatum transiently inhibits GPe NS disinhibition Gpi activation Indirect pathway http://www.slideshare.net/drpsdeb/presentations • NS activates GPi • GPe tonically inhibits NS • Corpus striatum transiently inhibits GPe NS disinhibition Gpi activation Indirect pathway http://www.slideshare.net/drpsdeb/presentations • NS activates GPi • GPe tonically inhibits NS • Corpus striatum transiently inhibits GPe NS disinhibition Gpi activation Indirect pathway http://www.slideshare.net/drpsdeb/presentations • NS activates GPi • GPe tonically inhibits NS • Corpus striatum transiently inhibits GPe NS disinhibition Gpi activation Indirect pathway http://www.slideshare.net/drpsdeb/presentations Indirect pathway http://www.slideshare.net/drpsdeb/presentations • NS activates GPi • GPe tonically inhibits NS • Corpus striatum transiently inhibits GPe NS disinhibition Gpi activation Indirect pathway • NS activates GPi • GPe tonically inhibits NS • Corpus striatum transiently inhibits GPe NS disinhibition Gpi activation • Less important is a direct inhibition of Gpi by GPe http://www.slideshare.net/drpsdeb/presentations Direct and indirect pathway differences • Direct pathway  Motor cortex activation • Indirect pathway  Motor cortex inhibition http://www.slideshare.net/drpsdeb/presentations Basal ganglia • Corpus striatum – Nucleus caudatus – Putamen • Globus pallidus (Pallidum) – Externum – Internum • Nucleus subthalamicus • Substantia nigra – Pars compacta – Pars reticulata • Thalamic motor nuclei http://www.slideshare.net/CsillaEgri/presentations Direct and indirect pathway differences • Direct pathway  Motor cortex activation • Indirect pathway  Motor cortex inhibition http://www.slideshare.net/drpsdeb/presentations Dopaminergic projections http://www.slideshare.net/drpsdeb/presentations • Dopaminergic projections are crucial for the function of corpus striatum • S. nigra pars compacta • Direct pathway activation  D1 receptors • Indirect pathway inhibition  D2 receptors Dopaminergic projections • Dopaminergic projections are crucial for the function of corpus striatum • S. nigra pars compacta • Direct pathway activation  D1 receptors • Indirect pathway inhibition  D2 receptors http://www.slideshare.net/drpsdeb/presentations Basal ganglia • Beside motor loop there are other loops associated with other thalamic nuclei • „Gating“ of the other sort of information • Association loop • Limbic loop • Basal ganglia play an important role in information processing in general and this is crucial for thinking process • Connections of corpus striatum are plastic what allows learning and this was very important during evolution Cerebellum http://www.slideshare.net/HarshshaH103/cerebellum-its-function-and-releveance-in-psychiatry Coordination Cerebellum Cerebellum plays an important role not only in the coordination of movement, but also in the "coordination" of thoughts