Which statement correctly describes the anterolateral spinothalamic pathway for pain and temperature?

Which statement correctly describes the anterolateral spinothalamic pathway for pain and temperature?

• A. They ascend ipsilaterally in the dorsal columns to the thalamus.
• B. They cross in the spinal cord at the level of entry and ascend contralaterally in the spinothalamic tract to the ventral posterolateral nucleus (VPL) of the thalamus and then to the somatosensory cortex.
• C. They project first to the cerebellum before reaching the thalamus.
• D. They terminate in the spinal cord without crossing and ascend to the cortex on the same side.

Answer: (B)

Pain and temperature travel through the anterolateral (spinothalamic) pathway by crossing in the spinal cord at the level of entry and then ascending on the opposite side in the spinothalamic tract to the ventral posterolateral nucleus (VPL) of the thalamus, from which they are relayed to the somatosensory cortex. This means the signals from one side of the body are ultimately processed in the opposite thalamus and cortex. The dorsal columns, in contrast, carry fine touch and proprioception and stay on the same side until they cross in the medulla, not in the spinal cord. Therefore the described route of crossing early in the spinal cord and terminating in the VPL before reaching the cortex best fits the pain and temperature pathway.

Pain and temperature travel through the anterolateral (spinothalamic) pathway by crossing in the spinal cord at the level of entry and then ascending on the opposite side in the spinothalamic tract to the ventral posterolateral nucleus (VPL) of the thalamus, from which they are relayed to the somatosensory cortex. This means the signals from one side of the body are ultimately processed in the opposite thalamus and cortex. The dorsal columns, in contrast, carry fine touch and proprioception and stay on the same side until they cross in the medulla, not in the spinal cord. Therefore the described route of crossing early in the spinal cord and terminating in the VPL before reaching the cortex best fits the pain and temperature pathway.