There is a whole sphere of mental activity that goes beyond simple perception of stimuli and logical formulation of responses. We have drives and urges, and most of our experiences are emotionally colored. This emotional coloring and its relationship with…
The cerebral cortex is ultimately the part of the CNS that makes us human. Other parts of the CNS like sensory pathways bring in raw data, the reticular activating system adjusts levels of excitability, but the cortex is where events…
Photoreceptors throughout the animal kingdom use G protein–coupled transduction mechanisms for added sensitivity, but they pay a price in speed: images need to stay still on the retina for a tenth of second or so at a time to be…
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…