The cerebellum helps coordinate movement by sampling most kinds of sensory information, comparing current movements with intended movements, and issuing planning or correcting signals. The comparisons are made in a uniform, precisely organized, cerebellar cortex, and the planning or correcting…
Historically, the basal ganglia have been considered as major components of the motor system. In fact, they have a much broader role than that and are probably involved to some extent in most forebrain functions. However, their relationship to movement…
The firing rates of our motor neurons, and therefore the states of contraction of our muscles, are determined by multiple influences. Simple reflex arcs like the stretch reflex and more complex motor programs like the basic pattern generator for walking…
The visual system is the most studied sensory system, partly because we are such a visually oriented species and partly because of its relative simplicity. In addition, the visual pathway is highly organized in a topographical sense, so even though…
The diencephalon is a relatively small, centrally located part of the cerebrum that, like the spinal cord and brainstem, is functionally important way out of proportion relative to its size. It is subdivided into four general regions, each with the…
The previous four chapters presented various aspects of the brainstem and its cranial nerves bit by bit. This chapter summarizes the major points, using as a vehicle the same series of drawings of brainstem sections used in Chapter 11 but…
The eighth nerve is the nerve of hearing and equilibrium. All of its receptive functions are accomplished by variations on a common theme; the different sensory information carried by different fibers in the nerve is simply the result of slight…
The Perception of Flavor Involves Gustatory, Olfactory, Trigeminal, and Other Inputs When we eat food or drink a beverage, we have a unified perception, centered on the tongue, of some mixture of flavors. However, this unified perception actually results from…
Cranial nerves and their central connections often look bewilderingly complicated, but for the most part they are actually arranged systematically. Cranial Nerve Nuclei Have a Generally Predictable Arrangement Key Concept The sulcus limitans intervenes between motor and sensory nuclei of…
The Brainstem Has Conduit, Cranial Nerve, and Integrative Functions The brainstem is another part of the CNS whose importance is out of proportion to its size. All of the long tracts traverse the brainstem on their way to or from…