Chapter 14 & 15 – The Cutaneous Senses & The Chemical Senses

Flashcards for Chapter 14 & 15 – The Cutaneous Senses & The Chemical Senses Exam IV Sensation and Perception Study Guide Vocabulary

Duplex theory of texture perception

The idea that texture perception is determined by both spatial and temporal cues that are detected by two types of receptors. Originally proposed by David Katz and now called the “duplex theory”.

Medial lemniscal pathway

A pathway in the spinal cord that transmits signals from the skin toward the thalamus

Multimodal nature of pain

The fact that the experience of pain has both sensory and emotional components.

Pacinian corpuscle

A receptor with a distinctive elliptical shape associated with RA2 mechanoreceptors. It transmits pressure to the nerve fiber inside it only at the beginning or end of a pressure stimulus and is responsible for our perception of vibration and fine textures when moving the fingers over a surface

PC fiber

Fiber in the skin associated with Pacinian corpuscle receptors that is located deeper in the skin than RA1 fibers

Proprioception

The sensing of the position of the limbs

RA1 fibers

Fiber in the skin associated with Meissner corpuscles that adapts rapidly to stimuli and fires only briefly when a tactile stimulus is presented

Rapidly adapting (RA) fiber

Fiber in the cutaneous system that adapts rapidly to a stimulus and so responds briefly to tactile stimulation

SA1 fibers

Fiber in the skin associated with Merkel receptors that adapts slowly to stimulation and so responds continuously as long as a tactile stimulus is applied

SA2 fiber

A slowly adapting fiber in the cutaneous system that is associated with the Ruffini cylinder and is located deeper in the skin than the SA1 fiber. This fiber also responds continuously to a tactile stimulus.

Secondary somatosensory cortex (S2)

The area in the parietal lobe next to the primary somatosensory area (S1) that processes neural signals related to touch, temperature, and pain.

Somatosensory receiving area (S1)

An area in the parietal lobe that receives inputs from the skin and the viscera associated with somatic senses such as touch, temperature, and pain

Somatosensory system

The system that includes the cutaneous senses (senses involving the skin), proprioception (the sense of position of the limbs), and kinesthesis (sense of movement of the limbs).

Spinothalamic pathway

One of the nerve pathways in the spinal cord that conducts nerve impulses from the skin to the somatosensory area of the thalamus.

Across-fiber patterns

The pattern of nerve firing that a stimulus causes across a number of neurons. Also referred to as distributed coding

Amiloride

A substance that blocks the flow of sodium into taste receptors

Chemotopic map

The pattern of activation in the olfactory system in which chemicals with different properties create a “map” of activation based on these properties. For example, there is evidence that chemicals are mapped in the olfactory bulb based on carbon-chain length. Also called odor map

Detection threshold

The minimum amount of energy that can be detected. The detection threshold for smell is the lowest concentration at which an odorant can be detected. This threshold is distinguished from the recognition threshold, which requires a higher concentration of odorant.

Forced-choice method

Method in which two choices are given, and the subject has to pick one. For example, a subject is presented with a weak odorant on one trial, and no odorant on another trial, and has to pick the trial on which the odorant was presented

Frontal operculum

An area in the frontal lobe of the cortex that receives signals from the taste system

Glomeruli

Small structures in the olfactory bulb that receive signals from similar olfactory receptor neurons. One function of each glomerulus is to collect information about a small group of odorants

Isolated congenital anosmia (ICA)

A condition in which a person is born without a sense of smell

Nucleus of the solitary tract

The nucleus in the brain stem that receives signals from the tongue, the mouth, and the larynx transmitted by the chorda tympani, glossopharyngeal, and vagus nerves

Odotopic map

The pattern of activation in the olfactory system in which chemicals with different properties create a “map” of activation based on these properties. For example, there is evidence that chemicals are mapped in the olfactory bulb based on carbon-chain length. Also called odor map

Orbitofrontal cortex

An area in the frontal lobe, near the eyes, that receives signals originating in the olfactory receptors. Also known as the secondary olfactory cortex.

Piriform cortex

An area under the temporal lobe that receives signals from glomeruli in the olfactory bulb. Also called the primary olfactory area

Primary olfactory area

A small area under the temporal lobe that receives signals from glomeruli in the olfactory bulb. Also called the piriform cortex

Recognition profile

The pattern of olfactory activation for an odorant, indicating which ORNs (olfactory receptor neurons) are activated by the odorant

Retronasal route

The opening from the oral cavity, through the nasal pharnyx, into the nasal cavity. This route is the basis for the way smell combines with taste to create flavor.

Secondary olfactory area

An area in the frontal lobe, near the eyes, that receives signals originating in the olfactory receptors. Also known as the orbitofrontal cortex.

Sensory-specific satiety

The effect on perception of the odor associated with food eaten to satiety . For example, after eating bananas until satiety, the pleasantness rating for vanilla decreased slightly (but was still positive), but the rating for banana odor decreased much more and became negative.