Embryological Disorders of the Brain

The correct answer is C.

Explanation:

The patient in question has a cerebellar lesion. Cerebellar dysfunction can lead to a variety of motor dysfunctions, including truncal ataxia (appearing similar to the gait of an intoxicated individual), intention tremor (uncontrolled shaking of affected extremity present only with purposeful movement), dysdiadochokinesia (the inability to perform rapid and regular alternating movements), dysmetria (inability to stop movements at the desired point), dysarthria (ataxic speech), hypotonia, and nystagmus.

During the fourth week of embryonic development, the anterior end of the neural tube develops three vesicles, the prosencephalon (forebrain), the mesencephalon (midbrain), and the rhombencephalon (hindbrain). By the sixth week, five vesicles (listed in the answer options) have developed. The rhombencephalon has now developed into the metencephalon and myelencephalon. The cerebellum and pons derive from the metencephalon.

The diencephalon (choice A), which is derived from the prosencephalon, develops into the thalamus, hypothalamus, epithalamus, subthalamus (everything with the word "thalamus"), posterior lobe of the pituitary, and neural retina.

The mesencephalon (choice B), or midbrain, is the only brain vesicle that does not produce a secondary vesicle; it remains the mesencephalon.

The myelencephalon (choice D), which is derived from the rhombencephalon, develops into the medulla oblongata.

The telencephalon (choice E), which is derived from the prosencephalon, develops into the cerebral hemispheres (cerebral cortex, basal ganglia, and deep white matter).

Category: