The Basal Ganglia: Dyskinesia

What are the two main functions of the basal ganglia?

1) Allowing desired movements to occur 2) Inhibiting competing (non-intended) movements from occurring

Name two common neurological disorders associated with the basal ganglia.

Parkinson's disease and Huntington's disease

What are the three regions of the basal ganglia?

1) Corpus Striatum 2) Subthalamic Nucleus 3) Substantia Nigra

What is the composition of the Corpus Striatum?

It is subdivided into the caudate and lentiform nuclei.

What are the components of the lentiform nuclei?

The Putamen and Globus Pallidus

What is the function of the caudate nucleus?

It has head, body, and tail regions located in the wall of the lateral ventricle.

What is the significance of the Substantia Nigra?

It is the largest nuclear mass of the midbrain and is characterized by melanin, giving it a black coloration.

What neurotransmitter is primarily involved in the nigrostriatal connection?

Dopamine

What is the chief output nucleus of the basal ganglia?

The medial pallidum

What are the positive signs of basal ganglia disorders?

Spontaneous actions the patient does not want to perform, such as dyskinesia and rigidity.

What is akinesia?

The inability to initiate movement, often seen in Parkinson's disease.

What are the hallmark symptoms of Parkinson's disease?

Tremor, Rigidity, Akinesia, and Postural instability (TRAP)

What is Huntington's disease characterized by?

Degeneration of striatal neurons, leading to symptoms like athetosis and chorea.

What is tardive dyskinesia?

A basal ganglia disorder involving involuntary movements of the face, lips, and tongue, often due to prolonged medication use.

What is the role of glutamate in the basal ganglia?

It is the primary excitatory neurotransmitter influencing the striatum and subthalamic nucleus.

What is the effect of D1 receptors in the basal ganglia?

They are excitatory and facilitate activity in the direct pathway.

What is the effect of D2 receptors in the basal ganglia?

They are inhibitory and decrease activity in the indirect pathway.

What is the clinical manifestation of lesions in the subthalamic nucleus?

Contralateral Hemiballismus, characterized by wild, involuntary movements of proximal limbs.

What is the primary inhibitory neurotransmitter in the basal ganglia?

GABA

What are the negative signs of basal ganglia disorders?

Actions a patient wants to perform but cannot, such as freezing gait patterns and abnormal posturing.

What is the significance of the pallidothalamic projections?

They are involved in the output of the basal ganglia to the thalamus.

What does the term 'hyperkinesia' refer to?

Clinical appearance seen with chorea, athetosis, ballismus, and tics.

What does 'hypokinesia' refer to?

Clinical appearance of akinesia, bradykinesia, rigidity, and impaired postural reflexes.

What is the role of the basal ganglia in voluntary movement?

They allow cortical initiation of desired voluntary movements and suppress undesired movements.

What is the impact of decreased dopamine in the striatum?

It leads to increased inhibition of the motor thalamus, decreasing activity between the thalamus and motor cortex.

What is the relationship between the basal ganglia and the pyramidal system?

The basal ganglia have a direct influence on the pyramidal system through thalamocortical projections.

What are the symptoms of cerebral palsy?

Common symptoms include spasticity and dyskinesia, affecting the CNS motor system and mental function.