Avoiding response is due to______ lesion in the brain
**Core Concept**
The question pertains to the concept of "avoiding response" or "paratonia," which is a type of motor reaction characterized by resistance to movement or passive movement due to the brain's inability to properly interpret sensory information. This is often seen in patients with frontal lobe lesions, particularly those affecting the premotor cortex.
**Why the Correct Answer is Right**
The correct answer is related to the lesion in the premotor cortex, which is responsible for the integration of sensory information and motor planning. In patients with premotor cortex lesions, the brain's ability to generate a motor response to a stimulus is disrupted, leading to a phenomenon known as "paratonia" or "gegenhalten." This is because the premotor cortex plays a crucial role in the regulation of motor tone and the planning of voluntary movements.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because lesions in the primary motor cortex would result in weakness or paralysis of the affected muscles, rather than an avoiding response.
**Option B:** This option is incorrect because lesions in the primary sensory cortex would result in loss of sensation in the affected area, rather than an avoiding response.
**Option C:** This option is incorrect because lesions in the basal ganglia would result in movement disorders such as Parkinson's disease or dystonia, rather than an avoiding response.
**Clinical Pearl / High-Yield Fact**
A key clinical feature of paratonia is the presence of "gegenhalten," which is a German term that literally means "against-holding." This refers to the patient's resistance to passive movement, often with a characteristic "clasp-knife" phenomenon where the patient's limb is stiff at first but then relaxes as the movement continues.
**Correct Answer:** B.