1. Basal ganglia movement modulation
Domina Petric, MD

2. Introduction
Basal ganglia are collection of nuclei that are found deep in the base of the forebrain.
Basal ganglia are developed from the telencephalon so the basal ganglia relate to the functions of the cerebral cortex.
Basal ganglia recieve inputs from various regions of the cerebral cortex.

3. Basal ganglia
Basal ganglia interact with upper motor neurons and are concerned with gating proper initiation of movement.
Ventral anterior-ventral lateral (VA-VL) complex of the thalamus sends signals up into the motor cortex: excitatory trigger for the execution of the movement.
Basal ganglia provide inhibitory output to the thalamus.
Thalamic input is crucial for the upper motor neurons to send excitatory signals to the lower motor neurons.
The basal ganglia has inhibitory control over the motor thalamus and that is how basal ganglia modulate movement control.

4. Major basal ganglia function is
MODULATION OF THALAMO-CORTICAL ACTIVITY!

5. Basal ganglia function
initiation of behavior
suppression of unwanted behavior

6. Parallel pathways (streams)
Body movement loop
Oculomotor loop
Motor loops
Prefrontal loop
Limbic loop
Non-motor loops

7. Parallel pathways (streams)
Cortical input
Basal ganglia: striatum
Basal ganglia: pallidum
Thalamus
Cortical targets

8. Body movement loop
Cortical input is from primary motor cortex, premotor cortex, supplementary motor cortex and somatosensory cortex.
That input goes first to the PUTAMEN and from the putamen to the LATERAL GLOBUS PALLIDUS.
From the basal ganglia input goes to the VA-VL thalamic nuclei complex.
Motor thalamus then sends signals into the motor cortex: INITIATION OF THE MOVEMENT or SUPRESSION OF UNWANTED MOVEMENTS.

9. Oculomotor loop
Cortical input is from the frontal eye field and supplementary eye field.
That input goes into the body of CAUDATE and from caudate into the GLOBUS PALLIDUS and SUBSTANTIA NIGRA (PARS RETICULATA).
Input then goes into the MEDIODORSAL AND VENTRAL ANTERIOR THALAMIC NUCLEI and then to cortical targets.

10. Prefrontal loop
Cortical input is from dorsolateral prefrontal cortex.
Input goes then into the ANTERIOR CAUDATE and then into the GLOBUS PALLIDUS and SUBSTANTIA NIGRA.
Input then goes into the MEDIODORSAL and VENTRAL ANTERIOR NUCLEUS of the THALAMUS.
Last station is cortical target.

11. Limbic loop
Last station is cortical target.
Thalamic station is MEDIODORSAL NUCLEUS.
Next station is VENTRAL STRIATUM and then VENTRAL PALLIDUM.
Cortical input is from anterior cingulate cortex, orbital frontal cortex, amygdala and hippocampus.

12. Basal ganglia dysfunction
Hypokinetic movement disorders (Parkinsonism): failure of initiation of the movement.
Hyperkinetic movement disorders (Huntington´s disease): failure of suppression of the unwanted movement.
Affective and cognitive disorders (depression, schizophrenia, Tourette´s syndrome): failure of initiation of a particular behavior program and/or failure of supression of an inappropriate behavior program.

13. Dopamine
Dopamine from the midbrain (Substantia nigra, pars compacta) is important neuromodulator of basal ganglia function.

14. Ventral tegmental area (VTA)
Ventral tegmental area provides a dopamine projection to the ventral part of the striatum that is included into the limbic processing stream.

15. They are important source of modulation of the basal ganglia.
Subthalamic nuclei
Subthalamic nuclei provide input to the internal part of the globus pallidus.
They are important source of modulation of the basal ganglia.

16. Putamen
Putamen is the principal recipient of the inputs from the frontal motor cortex and the parietal somatosensory cortex: MODULATION OF THE BODY MOVEMENTS.

17. Caudate nucleus
Caudate nucleus recieves inputs from the frontal cortex, the anterior part of the premotor cortex which includes frontal eye field: MODULATION OF THE EYE MOVEMENTS AND MOVEMENT OF THE MIND.

18. Nucleus accumbens
Nucleus accumbens is recieving input from the ventromedial parts of the forebrain that are concerned with processing EMOTION or AFFECT.

19. Basal ganglia pathways
SUBTHALAMIC NUCLEUS MODULATES ACTIVITY
OF GLOBUS PALLIDUM INTERNAL SEGMENT.
Basal ganglia pathways
Direct pathway
Indirect pathway
CORTEX
STRIATUM
PALLIDUM (INTERNAL SEGMENT)
THALAMUS
CORTEX
STRIATUM
GLOBUS PALLIDUM EXTERNAL SEGMENT
SUBTHALAMIC NUCLEUS
GLOBUS PALLIDUM INTERNAL SEGMENT

20. Literature
Leonard E. White, PhD, Duke University