7.1

• The sensory systems that detect stimuli outside of our bodies.

  exteroceptive sensory systems
• What are the systems that compose the exteroceptive sensory system?

  auditory, somatosensory, olfactory, gustatory
• The process of detecting the presence of stimuli.

  Sensation
• Types of Sensory Areas of Cortex

  Primary Sensory Cortex, Secondary Sensory Cortex, Association Cortex
• A system is the area of sensory cortex that receives most of its input directly from the thalamic relay nuclei of that system.

  Primary Sensory Cortex
• Areas of the sensory cortex that receive most of their input from the primary sensory cortex of that system or from other areas of secondary sensory cortex of the same system.

  Secondary Sensory Cortex
• Any area of the cortex that receives input from more than one sensory system. Most input to this area comes via areas of secondary sensory cortex.

  Association Cortex
• Features of Sensory System Organization

  Sensory systems are hierarchical, functionally segregated, and parallel.
• True or False, the higher the level of damage, the more specific and complex the deficit.

  True
• Destruction of a sensory system’s receptors produces a complete loss of ability to perceive in that sensory modality
• Destruction of an area of association or secondary sensory cortex typically produces complex and specific sensory deficits, while leaving fundamental sensory abilities intact.
• Each of the three levels of cerebral cortex—primary, secondary, and association—in each sensory system contains functionally distinct areas that specialize in different kinds of analysis. This shows that sensory systems is functionally segregated.
• Sensory systems are parallel systems in which information flows through the components over multiple pathways.
• Although sensory systems carry information from lower to higher levels of their respective hierarchies, they also conduct information in the opposite direction (from higher to lower levels). These are called as top-down signals.
• The function of the auditory system is the perception of sound.
• Sounds are vibrations of air molecules that stimulate the auditory system.
• Humans hear only those molecular vibrations between about 20 and 20,000 hertz (cycles per second).
• Amplitude = loudness
• Frequency = pitch
• Complexity = timbre