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CNS: Anatomy# Basal Nuclei
Q1. All of the following structures are anatomically included in the basal nuclei EXCEPT:
Corpus striatum
Amygdaloid nucleus
Substantia nigra
Claustrum
Explanation:
Substantia nigra is functionally related to basal nuclei but is not anatomically located within the cerebral white matter.
Q2. All of the following statements regarding basal nuclei are correct EXCEPT:
They play a role in posture control
They regulate voluntary movement
They have no direct spinal cord connections
They send efferent fibers directly to anterior horn cells
Explanation:
Basal nuclei do not have direct output to the spinal cord or anterior horn cells.
Q3. All of the following correctly describe the head of the caudate nucleus EXCEPT:
Large and rounded
Forms part of the floor of the lateral ventricle body
Forms the lateral wall of the anterior horn
Separated from lentiform nucleus by internal capsule
Explanation:
The body (not the head) forms part of the floor of the body of the lateral ventricle.
Q4. All of the following statements regarding the tail of the caudate nucleus are true EXCEPT:
Terminates posteriorly in the thalamus
Follows the contour of the lateral ventricle
Runs in the roof of the inferior horn
Terminates anteriorly in the amygdaloid nucleus
Explanation:
The tail terminates anteriorly in the amygdaloid nucleus, not posteriorly in the thalamus.
Q5. All of the following correctly describe the lentiform nucleus EXCEPT:
Wedge-shaped
Separated from thalamus by posterior limb of internal capsule
Putamen is darker than globus pallidus
Putamen lies medial to globus pallidus
Explanation:
Putamen lies lateral to globus pallidus, not medial.
Q6. All of the following statements regarding globus pallidus are correct EXCEPT:
Medial part is lighter due to myelinated fibers
Has internal and external segments
External segment sends fibers directly to cortex
Neurons are inhibitory
Explanation:
Globus pallidus does not project directly to the cortex.
Q7. All of the following are afferent inputs to the neostriatum EXCEPT:
Cortico-striate fibers
Thalamo-striate fibers
Nigro-striatal fibers
Pallido-striatal fibers
Explanation:
Pallido-striatal fibers are not described; striato-pallidal fibers are efferent.
Q8. All of the following neurotransmitters are correctly matched with their pathway EXCEPT:
Cortico-striate – Glutamate
Nigro-striatal – GABA
Striato-pallidal – GABA
Brainstem striatal – Serotonin
Explanation:
Nigro-striatal fibers release dopamine, not GABA.
Q9. All of the following statements regarding pallido-thalamic fibers are true EXCEPT:
They terminate in the ventral lateral nucleus
Include ansa lenticularis
Include fasciculus lenticularis
They unite to form the thalamic fasciculus
Explanation:
Pallido-thalamic fibers terminate in the Ventral Anterior (VA) nucleus, not VL.
Q10. All of the following events occur in the direct pathway EXCEPT:
Suppression of globus pallidus internal segment
Disinhibition of VA nucleus
Increased GABA release to cortex
Increased cortical motor activity
Explanation:
Cortical excitation occurs via glutamate, not GABA.
Q11. All of the following correctly describe the indirect pathway EXCEPT:
Inhibits undesired movements
Involves subthalamic nucleus activation
Increases GABA output to thalamus
Leads to increased motor cortex activity
Explanation:
The indirect pathway decreases motor cortex activity.
Q12. Dopamine effect on basal nuclei pathways is correctly described in all EXCEPT:
Stimulates direct pathway via D1 receptors
Stimulates indirect pathway via D2 receptors
Overall increases motor activity
Released from pars compacta
Explanation:
Dopamine inhibits the indirect pathway via D2 receptors.
Q13. Lesion of the indirect pathway results in all EXCEPT:
Hyperkinesia
Dyskinesia
Hypokinesia
Undesired movements
Explanation:
Hypokinesia results from direct pathway dysfunction.
Q14. Parkinson disease is associated with all of the following EXCEPT:
Increased dopamine levels
Degeneration of pars compacta
Bradykinesia
Masked facial expression
Explanation:
Parkinson disease involves dopamine deficiency.
Q15. All of the following statements regarding hemiballismus are correct EXCEPT:
Results from contralateral STN lesion
Often due to stroke
Involves proximal muscles
Usually bilateral
Explanation:
Hemiballismus is unilateral; bilateral involvement is ballismus.
Q16. All of the following capsule relationships are correct EXCEPT:
External capsule lies between lentiform nucleus and claustrum
Extreme capsule lies medial to claustrum
Internal capsule lies medial to lentiform nucleus
Extreme capsule lies medial to insula
Explanation:
Extreme capsule lies lateral to the claustrum, not medial.