Unit Eleven: The Nervous System: C. Motor and

Integrative Neurophysiology

Chapter 56: Contributions of the Cerebellum

And Basal Ganglia to Overall Motor Control

Guyton and Hall, Textbook of Medical Physiology, 12 edition

Cerebellum and Its Motor Functions

• The cerebellum plays major roles in the timingof motor activities and in rapid, smoothprogression from one muscle movement to the next.

• The basal ganglia help to plan and control complexpatterns of muscle movement

• Cerebellum helps to sequence motor activitiesand monitors and makes corrective adjustmentsduring motor activities

Cerebellum and Its Motor Functions

• The cerebellum receives continuously updated information from the brain motor control areas

• Aids the cerebral cortex in planning sequentialmovements

Anatomical Functional Areas of the Cerebellum

Fig. 56.1 Anatomical lobes of the cerebellum Fig. 56.2 Functional parts of the cerebellum

Anatomical Functional Areas of the Cerebellum

Fig. 56.3 Somatosensory projection areas in the cerebellar cortex Fig. 56.4 Principle afferent tracts to the cerebellum

Anatomical Functional Areas of the Cerebellum

Fig. 56.5 Spinocerebellar tracts Fig. 56.6 Principle efferent tracts from the cerebellum

Functional Unit of the Cerebellar Cortex

Fig. 56.7 The left side of this figure shows the basic neuronal circuit of the cerebellum, with the excitatory neurons shown in red, and the inhibitory neuron (Purkinje cell) shown in black.

Functional Unit of the Cerebellar Cortex

• Cerebellum has nearly 30 million nearly

identical functional units; a Purkinje cell

on a corresponding deep nuclear cell

• Three major layers

a. Molecular layerb. Purkinje cell layerc. Granule cell layer

Functional Unit of the Cerebellar Cortex

• Neuronal Circuit of the Functional Unit

a. Purkinje fibers and deep nuclear cells firecontinuously under normal resting conditions

b. Balance between excitation and inhibition at thedeep cerebellar nuclei

c. Other inhibitory cells1. Basket cells2. Stellate cells

Functional Unit of the Cerebellar Cortex

• Turn-On/Turn-Off and Turn-Off/Turn-On Output

Signals from the Cerebellum

• The Purkinje Cells Learn to Correct Motor Errors-

Role of the Climbing Fibers

Functional Unit of the Cerebellar Cortex

• Function of the Cerebellum in Overall Motor Control

a. Vestibulocerebellum functions in association with thebrain stem and spinal cord to control equilibrium andpostural movements

b. Spinocrebellum-feedback control of distal limb move-ments

1. Prevention of overshooting of movements andto “damp” movements

2. Control of ballistic movements

Functional Unit of the Cerebellar Cortex

• Function of the Cerebellum in Overall Motor Control

c. Cerebrocerebellum-function of the large lateral zoneto plan, sequence, and time complex movements

1. Planning of sequential movements2. Timing function3. Extramotor predictive functions

Basal Ganglia-Their Motor Functions

Fig. 56.9 Anatomical relations of the basal ganglia to the cerebral cortex and thalamus

Basal Ganglia-Their Motor Functions

Fig. 56.10 Relation of the basal gangli circuitry to the corticospinal-cerebellar system for movement control

• Neuronal Circuitry

Basal Ganglia-Their Motor Functions

Fig. 56.11 Putamen circuit

• Function of the Basal Ganglia in Executing Patternsof Motor Activity—the Putamen Circuit

Basal Ganglia-Their Motor Functions

• Neural Pathways of the Putamen Circuit

a. Abnormal function1. Athetosis2. Hemiballismus3. Chorea

Basal Ganglia-Their Motor Functions

• Role of the Basal Ganglia for Cognitive Control of Sequences of Motor Patterns—Caudate Circuit

Fig. 56.12 Caudate circuit through the basal ganglia

Basal Ganglia-Their Motor Functions

• Function of the Basal Ganglia to Change the Timingand to Scale the Intensity of Movements

a. Brain must determine how rapidly the movement isto be performed, and

b. Control how large the movement will be

Basal Ganglia-Their Motor Functions

• Functions of Specific Neurotransmitter Substancesin the Basal Ganglial System

Fig. 56.14

Integration of the Many Parts of the Total Motor Control System

• Spinal Level

• Hindbrain Level

• Motor Cortex Level

a. Associated functions of the cerebellum

b. Associated functions of the basal ganglia