Final answer:
The itch sensation is transmitted via the spinothalamic pathway, where sensory neurons send signals that decussate at the spinal cord level, ascend to the thalamus, and finally process in the primary somatosensory cortex of the brain.
Step-by-step explanation:
The neural pathway for itch, also known as pruritus, is closely related to the pathways for pain. The primary ascending tract involved in the transmission of itch sensations is the spinothalamic pathway. Sensory neurons detect itch-related stimuli and send signals through the peripheral nerves to the spinal cord.
These stimuli then ascend contralaterally within the spinothalamic tract after they decussate, or cross over, at the level of spinal entry. The signals travel to the thalamus, which plays a key role in routing sensory information to the appropriate areas of the brain. Finally, the neural signal undergoes processing in the primary somatosensory cortex of the brain, where the perception of itch is realized.
It's worth noting that similar to other sensory modalities, such as pain and temperature, the sensation of itch undergoes various processing stages involving different neurons and parts of the central nervous system, including the spinal cord, brain stem, and cerebral cortex.