Chapter 16.2, Problem 9AYLO

Summary Introduction

To discuss:

The pain pathways from receptors in the head to the cerebral cortex, including the cranial nerves that carry pain signals.

Introduction:

Somatosensory signals like facial sensations (from the head) reach the pons and medulla oblongata through various cranial nerves. The first-order nerve fibers of these somatosensory neurons synapse with the second-order neurons in the brainstem. Most of these neurons (second-order somatosensory) synapse with the third-order in the contralateral thalamus. The third-order somatosensory neurons complete the pathway to the brain (cerebrum). The second-order nerve fibers carry the proprioceptive signals (from the head) to the cerebellum.