Depicted are parts of the basal ganglia and their interconnections as revealed by diffusion spectrum imaging based on thirty subjects from the human connectome project (HCP MGH). Direct, indirect and hyperdirect pathways are visualized in different colors (see legend). Subcortical structures are rendered based on the Harvard-Oxford subcortical (Thalamus) as well as the Atlasing of the Basal Ganglia atlas (other structures). Rendering was generated using TrackVis software.
Overview of neuronal connections and normal function
The direct pathway passes through the caudate nucleus, putamen, and globus pallidus, which are parts of the basal ganglia. It also involves another basal ganglia component the substantia nigra, a part of the midbrain.[2] In a resting individual, a specific region of the globus pallidus, the internal globus pallidus (GPi), and a part of the substantia nigra, the pars reticulata (SNpr), send spontaneous inhibitory signals to the ventral lateral nucleus (VL) of the thalamus, through the release of GABA, an inhibitory neurotransmitter.[3] Inhibition of the inhibitory neurons that project to the ventral anterior nucleus (VA), which project to the motor regions of the cerebral cortices of the telencephalon, leads to an increase in activity in the motor cortices, thereby promoting muscular action.
When the pre-frontal region of the cerebral cortex, which is generally involved in decision making and planning, determines that a particular motor activity will be executed, it sends activating signals to the motor cortices. The motor cortices send signals through the basal ganglia to refine the choice of muscles that will participate in the movement and to amplify the activity in the motor cortices that will drive the muscle contractions.[4]
In the direct pathway, the motor cortices send activating signals to the caudate and putamen (which together form the dorsal striatum). The cells of the direct pathway in the caudate and putamen that receive these signals are inhibitory and, once they become activated, send inhibitory signals to the GPi and SNpr and stop activity there. Before activation of the direct pathway, these two nuclei were actively sending inhibitory signals to the ventrolateral nucleus of the thalamus, which prevented the development of significant activity in the motor cerebral cortices. This behavior ceases on activation of the direct pathway. The net effect is to allow the activation of the ventral lateral nucleus which, in turn, sends activating signals to the motor cortices. These events amplify motor cortical activity that will eventually drive muscle contractions.
Diseases involving the direct pathway
Interruption or dysfunction of the direct pathway results in hypokinesia, which is, in general terms, a disease which leads to a lack of motion in our body
References
^Nambu A (2004). "A new dynamic model of the cortico-basal ganglia loop". Prog. Brain Res. Progress in Brain Research. 143: 461–466. doi:10.1016/S0079-6123(03)43043-4. ISBN9780444513892. PMID 14653188.
^Pollack AE (August 2001). "Anatomy, physiology, and pharmacology of the basal ganglia". Neurol Clin. 19 (3): 523–34, v. doi:10.1016/s0733-8619(05)70032-3. PMID 11532641.
^Hauber W (December 1998). "Involvement of basal ganglia transmitter systems in movement initiation". Prog. Neurobiol. 56 (5): 507–40. doi:10.1016/S0301-0082(98)00041-0. PMID 9775402. S2CID 9986326.
^Bolam JP, Hanley JJ, Booth PA, Bevan MD (May 2000). "Synaptic organisation of the basal ganglia". J. Anat. 196 ( Pt 4) (4): 527–42. doi:10.1046/j.1469-7580.2000.19640527.x. PMC1468095. PMID 10923985.
February 01, 2023
direct, pathway, direct, pathway, sometimes, known, direct, pathway, movement, neural, pathway, within, central, nervous, system, through, basal, ganglia, which, facilitates, initiation, execution, voluntary, movement, works, conjunction, with, indirect, pathw. The direct pathway sometimes known as the direct pathway of movement is a neural pathway within the central nervous system CNS through the basal ganglia which facilitates the initiation and execution of voluntary movement 1 It works in conjunction with the indirect pathway Both of these pathways are part of the cortico basal ganglia thalamo cortical loop Depicted are parts of the basal ganglia and their interconnections as revealed by diffusion spectrum imaging based on thirty subjects from the human connectome project HCP MGH Direct indirect and hyperdirect pathways are visualized in different colors see legend Subcortical structures are rendered based on the Harvard Oxford subcortical Thalamus as well as the Atlasing of the Basal Ganglia atlas other structures Rendering was generated using TrackVis software Overview of neuronal connections and normal function EditThe direct pathway passes through the caudate nucleus putamen and globus pallidus which are parts of the basal ganglia It also involves another basal ganglia component the substantia nigra a part of the midbrain 2 In a resting individual a specific region of the globus pallidus the internal globus pallidus GPi and a part of the substantia nigra the pars reticulata SNpr send spontaneous inhibitory signals to the ventral lateral nucleus VL of the thalamus through the release of GABA an inhibitory neurotransmitter 3 Inhibition of the inhibitory neurons that project to the ventral anterior nucleus VA which project to the motor regions of the cerebral cortices of the telencephalon leads to an increase in activity in the motor cortices thereby promoting muscular action When the pre frontal region of the cerebral cortex which is generally involved in decision making and planning determines that a particular motor activity will be executed it sends activating signals to the motor cortices The motor cortices send signals through the basal ganglia to refine the choice of muscles that will participate in the movement and to amplify the activity in the motor cortices that will drive the muscle contractions 4 In the direct pathway the motor cortices send activating signals to the caudate and putamen which together form the dorsal striatum The cells of the direct pathway in the caudate and putamen that receive these signals are inhibitory and once they become activated send inhibitory signals to the GPi and SNpr and stop activity there Before activation of the direct pathway these two nuclei were actively sending inhibitory signals to the ventrolateral nucleus of the thalamus which prevented the development of significant activity in the motor cerebral cortices This behavior ceases on activation of the direct pathway The net effect is to allow the activation of the ventral lateral nucleus which in turn sends activating signals to the motor cortices These events amplify motor cortical activity that will eventually drive muscle contractions Diseases involving the direct pathway EditInterruption or dysfunction of the direct pathway results in hypokinesia which is in general terms a disease which leads to a lack of motion in our bodyReferences Edit Nambu A 2004 A new dynamic model of the cortico basal ganglia loop Prog Brain Res Progress in Brain Research 143 461 466 doi 10 1016 S0079 6123 03 43043 4 ISBN 9780444513892 PMID 14653188 Pollack AE August 2001 Anatomy physiology and pharmacology of the basal ganglia Neurol Clin 19 3 523 34 v doi 10 1016 s0733 8619 05 70032 3 PMID 11532641 Hauber W December 1998 Involvement of basal ganglia transmitter systems in movement initiation Prog Neurobiol 56 5 507 40 doi 10 1016 S0301 0082 98 00041 0 PMID 9775402 S2CID 9986326 Bolam JP Hanley JJ Booth PA Bevan MD May 2000 Synaptic organisation of the basal ganglia J Anat 196 Pt 4 4 527 42 doi 10 1046 j 1469 7580 2000 19640527 x PMC 1468095 PMID 10923985 Retrieved from https en wikipedia org w index php title Direct pathway amp oldid 1047682134, wikipedia, wiki, book, books, library,
