Final answer:
The labeled line theory, which is true, suggests that specific sensory modalities follow discrete pathways from the periphery to specific areas of the brain for processing, such as the dorsal column system or spinothalamic tract for somatosensory stimuli.
Step-by-step explanation:
The statement that the labeled line theory is based on the assumption that there is a discrete pathway from a sensory cell to the integrating center is true. This theory implies that specific sensory receptors are dedicated to transmitting information about a particular modality of sensation such as touch, temperature, or pain, to distinct areas of the brain for processing. Ascending pathways, such as the dorsal column system and the spinothalamic tract, convey information from the periphery to the brain, and each sensory modality follows these specific pathways.
For instance, somatosensory stimuli from the body travel through the spinal cord while those from the face travel through cranial nerves, like the trigeminal system. In the cerebral cortex, the primary sensory cortex processes the basic information which is then refined in association areas and integrated in multimodal areas for a complete perceptual experience.