Chapter 7 — Hearing, Touch, Smell, Taste, and Attention

Hierarchical organization

Information is processed through successive levels, with higher levels dealing with increasingly complex aspects of sensory information.

Functional segregation

Different areas of the brain specialize in processing different types of sensory information.

Parallel processing

Different aspects of information can be processed simultaneously by separate neural pathways.

Example:

When looking at an object, different neural systems can process its:

- shape

- color

- movement

- location

at the same time.

Sound

A form of physical energy produced by vibrations.

Major structures:

Outer ear → middle ear → inner ear → auditory nerve → brainstem → thalamus → auditory cortex

Cochlea

The inner-ear structure that converts sound vibrations into neural signals.

Basilar membrane

A structure within the cochlea that responds differently to different sound frequencies.

Auditory cortex

The cortical area involved in processing auditory information.

Sound localization

The ability to determine where a sound originates.

Somatosensory System

Processes sensations involving:

- touch

- pressure

- temperature

- pain

- body position

Cutaneous receptors

Sensory receptors located in the skin.

Dermatomes

Areas of the body associated with particular spinal nerves.

Primary somatosensory cortex

The cortical area that receives and processes much of the body's somatosensory information.

Somatosensory pathways

The two major pathways carrying somatosensory information toward the brain.

Pain

A sensory and emotional experience associated with actual or potential tissue damage.

Neuropathic pain

Pain resulting from abnormal functioning or damage within the nervous system.

Olfaction

The sense of smell.

Olfactory receptors

Receptors that detect chemicals associated with odors.

Olfactory glomeruli

Structures in the olfactory bulb where information from olfactory receptor neurons is organized.

Taste receptor proteins

Proteins involved in detecting different taste stimuli.

Gustation

The sense of taste

Selective attention

The ability to focus on some sensory information while ignoring other

information.

Change blindness

Failure to notice changes in a visual scene.

Simultanagnosia

Difficulty perceiving more than one object at a time.