**Core Concept:**
The somatosensory system is responsible for detecting external stimuli affecting the skin, muscles, ligaments, and joints, and transducing these mechanical signals into electrical impulses that can be processed by the central nervous system. The primary function of this system is to provide information about the location, size, shape, texture, and position of the body parts in relation to other parts and the external environment.

**Why the Correct Answer is Right:**
The correct answer, the **Cerebral Cortex**, is the highest-level part of the somatosensory system that processes the information received from the thalamus and other subcortical nuclei. The cerebral cortex is known for its remarkable capacity to integrate complex sensory information, including spatial and temporal fidelity of the somatosensory input.

**Why Each Wrong Option is Incorrect:**
A. **Thalamus:** Although the thalamus plays a crucial role in relaying somatosensory information from the spinal cord to the cerebral cortex, it does not have the highest degree of temporal and spatial fidelity.

B. **Spinal Cord:** While the spinal cord is involved in transmitting somatosensory information, it lacks the sophistication and integration capabilities of the cerebral cortex, making it an incorrect answer to this question.

C. **Peripheral Nervous System (PNS):** The PNS is responsible for transmitting somatosensory information to the central nervous system, but it does not possess the level of temporal and spatial processing found in the cerebral cortex, making it an incorrect answer.

D. **Spinal Cord and Medulla Oblongata:** These structures are part of the PNS and relay somatosensory information to the CNS, but they do not have the sophistication in processing spatial and temporal information as the cerebral cortex does.

**Clinical Pearl:**
The somatosensory system plays a vital role in maintaining bodily awareness, reflexes, and motor control. A deep understanding of the somatosensory pathways and processing centers is essential for accurate diagnosis and treatment planning in clinical practice.