04-02-2009, 03:33 PM
48. A brain MRI scan taken from a 6-month-old baby revealed that while the overall size of the cerebral cortex was normal, the size of the pyramidal tracts was considerably smaller than normal. The most likely explanation for this defect is that there is a
a. Reduction in the numbers of cortical neurons giving rise to pyramidal tract fibers
b. Reduction in the numbers of synaptic contacts made by pyramidal tract neurons
c. Reduction in the extent of myelin found on pyramidal tract neurons
d. Reduction in the amount of neurotransmitter released by pyramidal tract neurons
e. Reduction in the numbers of glial cells attached to pyramidal tract neurons
a. Reduction in the numbers of cortical neurons giving rise to pyramidal tract fibers
b. Reduction in the numbers of synaptic contacts made by pyramidal tract neurons
c. Reduction in the extent of myelin found on pyramidal tract neurons
d. Reduction in the amount of neurotransmitter released by pyramidal tract neurons
e. Reduction in the numbers of glial cells attached to pyramidal tract neurons