![]() ![]() The dorsal column system (sometimes referred to as the dorsal column–medial lemniscus) and the spinothalamic tract are two major pathways that bring sensory information to the brain (Figure 1). The sensory pathways in each of these systems are composed of three successive neurons.įigure 1. Ascending Sensory Pathways of the Spinal Cord. Somatosensory stimuli from below the neck pass along the sensory pathways of the spinal cord, whereas somatosensory stimuli from the head and neck travel through the cranial nerves-specifically, the trigeminal system. However, the somatosensory pathways are divided into two separate systems on the basis of the location of the receptor neurons. Tactile and other somatosensory stimuli activate receptors in the skin, muscles, tendons, and joints throughout the entire body. Each of the various sensory modalities follows a specific pathway through the CNS. Spinal Cord and Brain StemĪ sensory pathway that carries peripheral sensations to the brain is referred to as an ascending pathway, or ascending tract. The important regions of the CNS that play a role in somatic processes can be separated into the spinal cord brain stem, diencephalon, cerebral cortex, and subcortical structures. More complex arrangements are possible to integrate peripheral sensory information with higher processes. A simple case is a reflex caused by a synapse between a dorsal sensory neuron axon and a motor neuron in the ventral horn. Specific regions of the CNS coordinate different somatic processes using sensory inputs and motor outputs of peripheral nerves. Describe two pathways of visual processing and the functions associated with each.Explain topographical representations of sensory information in at least two systems.Describe the pathway of somatosensory input from the face and compare it to the ascending pathways in the spinal cord.Differentiate between the two major ascending pathways in the spinal cord.Describe the pathways that sensory systems follow into the central nervous system. ![]()
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