With brain lesions, which of the following reflex changes might occur?

• A. All reflexes become hyperactive
• B. Reflexes are unchanged
• C. Some reflexes may diminish or become absent, and abnormal reflexes may appear
• D. Only superficial reflexes change

Answer: (C)

Reflex changes after brain lesions can be mixed rather than uniform, because brain damage can disrupt multiple control and modulation pathways that shape how reflexes appear. Upper motor neurons and cortical networks normally regulate and refine reflexes, so injury can remove inhibitory influence and make some reflexes more active. At the same time, damage can interrupt the circuits needed to elicit certain reflexes, causing others to be diminished or absent. Additionally, loss of cortical control can release primitive reflexes, leading to abnormal responses such as Babinski or grasp reflexes emerging.

So the pattern described—that some reflexes may diminish or become absent, and abnormal reflexes may appear—best fits what can happen with brain lesions. The other descriptions don’t capture this mixed picture: reflexes aren’t universally hyperactive, they aren’t always unchanged, and the changes aren’t limited to superficial reflexes alone.