Deep Brain Structures Flashcards
Associated nuclei of basal ganglia
Caudate nucleus
Putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra
(Pedunculopontine nucleus)
Parkinson’s disease
Reduction in striatal dopamine due to degeneration of Substantia nigra
Huntington’s chorea
Hereditary disorder with chorea and dementia
Hemiballism
Due to lesion in the Subthalamic nucleus
Surgical treatment of Parkinson’s disease
Involves making lesions or inserting stimulating electrodes into different regions of the basal ganglia
Lentiform nucleus
Putamen
Globus pallidus
Striatum
Caudate nucleus
Putamne
Corpus striatum
Caudate nucleus
Putamen
Globus pallidus
2 parts of Globus pallidus
GP externis
GP internis
2 parts of the Subthalamic nucleus
Pars compacta
Pars reticularis
What separates the caudate nucleus and Putamen
Internal capsule
Function of basal ganglia
Related to motor refinement, acting as a tonically active break, preventing unwanted movements to start
Reducing excitatory input to cerebral cortex - prevents excessive and exaggerated movement
Modulates cognitive and emotional responses
Inputs to Putamen
From motor and somatosensory cortices
Outputs of Putamen
Motor areas of cortex
Input of caudate nucleus
Cortical association areas
Output of caudate nucleus
Prefrontal areas
Inputs of ventral striatum
Limbic inputs- related to emotions
Arterial supply of basal ganglia is mainly from
Middle cerebral artery —> lenticulostraite artery
Periaqueductal grey function
Receives input from somatosensory cortex
Part of descending pain pathway
Location of Periaqueductal grey
Grey matter around cerebral aqueduct in midbrain
Functions of basal ganglia
Facilitates purposeful behaviour and movement
Inhibits unwanted movement
Controls posture and movement
Selects which competing systems to activate- emotions, cognition, sensorimotor
Motor disorders of basal ganglia
Parkinson’s disease = lack of dopamine
Huntington’s disease = excess dopamine
Psychiatric disorders of basal ganglia
OCD
ADHD
Secondary damage to basal ganglia
Cerebral palsy
Wilson disease
Wilson disease
Excessive storage of copper in the liver, eyes and brain
Results in CNS dysfunction and hepatic disease
Symptoms of Parkinson’s disease
Spasticity
Reduced movement
Bradykinesia
Tremor
Muscle rigidity
Pathophysiology of Parkinson’s
Loss of dopaminergic neurons in Substantia nigra
Treatment of Parkinson’s
L-dopa= aims to correct dopamine deficiency
Converted into dopamine by serotonin neurons
Wear-off effect- drugs only work for a limited time, once wear off symptoms can come back worse
Pathophysiology of Huntington’s disease
36+ CAG repeats
Too little GABA resulting in too much dopamine
Autosomal dominant with full Penetrance
Treatment of Huntington’s
Dopamine receptor blockers
Symptoms of Huntington’s
Dementia
Personality change
Atrophy of the ventricles resulting in destruction of the striatum- particularly caudate nucleus