Unit 3_Basal Ganglia Flashcards
What functions do the following contribute to?
1. Contribute to normal movement patterns
2. Planning and execution of complex motor tasks
3. Control fast (saccadic) eye movements
4. Establishment of motor memories
5. Involved in our psychological well being and with the production of emotional responses
Basal Ganglia
What are the following components included in?
Input (receptive) is Striatum (Caudate and Putamen)
Output (Projection) is Pallidum (Globus Pallidus)
Basal Ganglia
What are the following structures included in?
1. Caudate nucleus (Dorsal Striatum)
2. Putamen (Dorsal Striatum)
3. Globus pallidus (Dorsal Pallidum)
Internal and external (projection modulation) segments
Substantia nigra reticulata (SNR)
4. Nucleus Accumbens (Ventral Striatum)
5. Ventral Pallidum
Basal Ganglia
What are the following internal modulatory structures included in?
1. Globus Pallidus (External segment)
2. Substantia nigra (midbrain)
Substantia nigra compacta (SNC)
3. Subthalamic nucleus (projection modulation)(ventral to the thalamus)
Basal Ganglia
What are the following functional circuits for?
Motor
Oculomotor
Executive/Association (Prefrontal)
Limbic (Emotion/Motivation)
Basal ganglia
What are the four basal ganglia loops?
Motor
Oculomotor
Executive/Association (Prefrontal)
Limbic (Emotion/Motivation)
Each Functional Circuit has an ______ and _____ portion.
input and output
The nuclei that comprise the basal ganglia can be divided functionally into _______ or _______portions and _________.
receptive or projection portions and modulators.
Many brain regions project into the basal ganglia and synapse on cells in the basal ganglia.
Structures that receive this information are referred to as what?
the receptive components of the basal ganglia
Many brain regions project into the basal ganglia and synapse on cells in the basal ganglia. Structures that output information form what?
the projection portion of the basal ganglia
What kind of organization is throughout the motor circuit?
Somatotopic
What is the input (receptive) in the Basal Ganglia?
is Striatum (Caudate and Putamen)
What is the output (projection) in the Basal Ganglia?
Pallidum (Globus Pallidus)
What circuit in the basal ganglia includes the following?
Afferent:
somatic sensory cortex
primary motor cortex
premotor and supplementary motor areas
Receptive = Putamen
Projection = GPI and SNR through VL and VA nuclei of the thalamus back to the cortex
The Motor Circuit
Normally, neurons in the internal segment of the globus pallidus and in the substantia nigra reticulata are tonically active at rest.
This activity will tend to __________ activity in the motor-related cortex.
suppress (inhibit)
The high tonic activity in neurons of the projection portion of the basal ganglia will _______ activity in motor-related cortex at rest.
inhibit
When a movement is desired and the motor-related regions of the cortex become active, neurons in the receptive portion of the basal ganglia are stimulated by the cortical neurons.
The result will be to _______ the inhibition of the motor cortex normally produced by neurons in the projection portion of the basal ganglia and it allows you to move.
remove
What circuit in the basal ganglia includes the following?
A portion of the basal ganglia that has to do with the production of saccadic eye movements.
Most of the afferent fibers to this circuit come from the cerebral cortex.
The major contributor is the frontal eye fields of the frontal lobe.
There is a robust connection with the superior colliculus.
The oculomotor circuit
What circuit in the basal ganglia includes the following?
This circuit is poorly understood but is believed to play a role in the formation of memories concerned with orientation in space.
Lesions of this brain region produce an impairment of working memories that have a spatial component. These memories are used to help direct a future movement when that movement is based on information that must be recalled about the spatial environment.
The Executive circuit
What circuit in the basal ganglia includes the following?
The circuit may have a role in the production of emotional responses.
This circuit has also been implicated in OCD and substance abuse/addictions
The Limbic circuit
What disease involves the loss of dopamine because of degeneration in the Substantia nigra?
When dopamine is missing these stimulation of motor cortical areas are no longer activated to the same extent by the motor circuit of the basal ganglia.
The symptoms of the disease are indicative of the underlying pathology. Bradykinesia, akinesia, a mask like expression of the face, and a shuffling gait are all symptoms of the disease.
Parkinson’s Disease
What disease is caused by destruction of the subthalamic nucleus?
Normally during a movement, neurons in the subthalamic nucleus are responsible for dampening excessive movement.
The disease is characterized by wild, uncontrolled, involuntary movements.
Hemiballismus
What disease involves the death of putamen neurons which project to the external segment of the globus pallidus produces involuntary movements that look like fragments of goal-directed movements?
Involuntary motions are produced.
Chorea
What disease produces chorea? It is a hereditary disorder that presents as a progressive degenerative disorder in the fourth of fifth decade of life. Symptoms include severe personality changes, cognitive impairments, and movement disorders such as chorea.
Huntington’s Chorea
