3. Control of reflex muscular activity

Some of the reflex muscular activities, particularly visual and labyrinthine reflexes are important in the maintenance of posture. Coordination and integration of impulses for these activities depend upon basal ganglia.

During lesion of basal ganglia, postural movements, especially visual and labyrinthine reflexes become abnormal. These abnormal movements are associated with rigidity. Rigidity is because of the loss of inhibitory influence from the cerebral cortex on spinal cord via basal gangliа

4. Control of automatic associated movements

Automatic associated movements are the movements in body, which take place along with some motor activities. Examples are the swing of the arms while walking, appropriate facial expressions while talking or doing any work. Basal ganglia are responsible for these movements. The lesion in basal ganglia causes absence of these automatic associated movements, resulting in poverty of movements. Face without appropriate expressions while doing any work is called mask like face. Body without associated movements is called statue like body.

5. Role in arousal (excitive) mechanism

Globus pallidus and red nucleus are involved in arousal mechanism because of their connections with reticular formation. Extensive lesion in globus pallidus causes drowsiness, leading to sleep.

ROLE OF NEUROTRANSMITTERS IN THE FUNCTIONS OF BASAL GANGLIA

The functions of basal ganglia on motor activities are executed by some neurotransmitters released by nerve endings within basal ganglia. Following neurotransmitters are released in basal ganglia.

Dopamine: It is released by dopaminergic fibers from substantia nigra to corpus striatum (putamen and caudate nucleus - nigra strial fibers). The deficiency of dopamine leads to Parkinsonism.

Gamma aminobutyric acid (GABA): It is secreted by intrinsic fibers of corpus striatum and substantia nigra.

Acetylcholine: It is released by fibers from cerebral cortex to caudate nucleus and putamen.

Substance P and enkephalins: These are released by fibers from globus pallidus reaching substantia nigra.

Noradrenaline: This is secreted by the fibers between basal ganglia and reticular formation.

Among all these neurotransmitters, dopamine and GABA are inhibitory neurotransmitters. So, the dopaminergic fibers and the fibers releasing GABA are inhibitory fibers. All other transmitters possess excitatory function.

4.Materials for auditory self-work.

4.1.List of study practical tasks necessary to perform at the practical class.

Materials and methods: bed.

Investigation object: human being.

Task 1. To investigate movement co-ordination

Romberg’s pose - the investigated person is proposed to move his feet together, to rise his head, to put his hands alongside his trunk. To determine whether his pose is stable. Complicated Romberg’s pose: the doctor proposes to the investigated person to stretch his hands forward horizontally. Initially his eyes must be opened, than closed. Cerebellum functions disorders are accompanied by unstable pose (falling forward is observed at vermis anterior parts injuries; ahead - at vermis caudal parts disorders).

Walking - the investigated person must go on right line with his opened eyes, then with closed ones. At good performing these tests the investigated person is proposed to go on right line such that sock of one foot was touched to the heel of the other one.

Phalanx walking - step movements towards; the investigator put his attention to the step clearance and to the possibility of fast stoppage at sudden order (at injury one can see ataxic walking: legs are significantly extensed and putted forward).