Which of the following manifestation occur secondary to ablation of the ‘somatosensory area I’ of the cerebral coex?
**Core Concept**
The somatosensory area I (also known as the primary somatosensory cortex) is a critical region in the cerebral cortex responsible for processing basic tactile information, such as touch, pressure, and vibrations. This area is organized in a somatotopic manner, meaning that different parts of the body are represented in distinct areas of the cortex.
**Why the Correct Answer is Right**
Ablation of the somatosensory area I would lead to deficits in processing basic tactile information. Patients with damage to this area may exhibit impaired tactile perception, including difficulties in identifying shapes, textures, and temperatures. This is due to the loss of direct connections between the thalamus and the primary somatosensory cortex, which are essential for transmitting sensory information to the cortex.
**Why Each Wrong Option is Incorrect**
**Option A:** Motor weakness
This option is incorrect because the primary somatosensory cortex is not directly involved in motor function. Motor weakness would be more likely associated with damage to the primary motor cortex.
**Option B:** Visual field defect
This option is incorrect because the primary somatosensory cortex is not responsible for processing visual information. Damage to this area would not result in visual field defects.
**Option C:** Aphasia
This option is incorrect because the primary somatosensory cortex is not involved in language processing. Aphasia is typically associated with damage to Broca's area or Wernicke's area in the language network of the brain.
**Option D:** Loss of olfactory function
This option is incorrect because the primary somatosensory cortex is not responsible for processing olfactory information. Damage to this area would not result in loss of olfactory function.
**Clinical Pearl / High-Yield Fact**
The primary somatosensory cortex is often referred to as the "sensory homunculus," due to its somatotopic organization, which maps different parts of the body onto distinct areas of the cortex.
**Correct Answer: A. Impaired tactile perception**