Chapter 14

Front 1

circadian rhythm

Back 1

A pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period

Front 2

diurnal

Back 2

Active during the light periods of the daily cycle

Front 3

Nocturnal

Back 3

Active During the dark periods of the daily cycle

Front 4

free-running

Back 4

referring to a rhythm of behavior shown by an animal deprived of external cues about time of day

Front 5

period

Back 5

the interval of time between two similar points of successive cycles, such as sunset to sunset

Front 6

phase shift

Back 6

a shift in the activity if a biological rhythm, typically provided by a synchronizing environmental stimulus

Front 7

entrainment

Back 7

the process of synchronizing a biological rhythm to an environmental stimulus

Front 8

zeitgeber

Back 8

Literally "time-giver" the stimulus that entrains circadian rhythms

Front 9

suprachiasmatic nucleus (SCN)

Back 9

A small region of the hypothalamus above the optic chiasm that is the location of the circadian oscillator

Front 10

pineal Gland

Back 10

a secretory gland in the brain midline, the source of melatonin release

Front 11

retinohypothalamic pathway

Back 11

the projection of retinal ganglion cells to the SCN

Front 12

melanopsin

Back 12

A photopigment found within particular retinal ganglion cells that project to the SCN

Front 13

Dimer

Back 13

a complex of two proteins that have bound together

Front 14

ultradian

Back 14

referring to the rhythmic biological event whose period is shorter than that of circadian rhythm, usually from several minutes to several hours

Front 15

circannual

Back 15

occurring on a roughly annual basis

Front 16

infradian

Back 16

referring to a rhythmic biological event whose period is longer than that of the circadian rhythm--longer than a day

Front 17

eletroencephalography (EEG)

Back 17

the recording and study of gross electrical activity of the brain recorded from large electrodes placed on the scalp

Front 18

electro-oculography (EOG)

Back 18

the electrical recording of eye movements

Front 19

electromyography (EMG)

Back 19

the electrical recoding of muscle activity

Front 20

slow-wave sleep (SWS)

Back 20

sleep, divided into stages 1-4, that is defined by the presence of slow-wave EEG activity

Front 21

rapid eye movement (REM) sleep

Back 21

stage of sleep characterized by small-amplitude, fast EEG waves, no postural tension, and rapid eye movements

Front 22

stage 1 sleep

Back 22

the initial stage of slow wave sleep, which is characterized by small-amplitude EEG waves of irregular frequency, slow heart rate, and reduced muscle tension

Front 23

stage 2 sleep

Back 23

a stage of slow-wave sleep that is defined by bursts of regular 14-18 Hz EEG waves called sleep spindles

Front 24

stage 3 and 4 sleep

Back 24

(has delta waves)

Front 25

Delta waves

Back 25

the slowest type of EEG wave, characteristic of stages 3 and 4 slow wave sleep

Front 26

stimulus

Back 26

a physical event that triggers a sensory response

Front 27

receptor cell

Back 27

a specialized cell that responds to a particular energy or or substance in the internal or external environment, and converts this energy into a change in the electrical potential across its membrane

Front 28

adequate stimulus

Back 28

The type of stimulus for which a given sensory organ is particularly adapted

Front 29

specific nerve energies doctrine

Back 29

The doctrine that the receptors and neural channels for the different senses are independent and operate in their own special ways, and can produce only one particular sensation each

Front 30

labeled lines doctrine

Back 30

the concept that each nerve input to the brain reports only a particular type of information

Front 31

sensory transduction

Back 31

the process in which a receptor cell converts the energy in a stimulus into a change in the electrical potential across its membrane

Front 32

generator potential

Back 32

a local change in the resting potential of a receptor cell that mediates between the impact of stimuli and the initiation of nerve impulses

Front 33

pacinian corpuscle

Back 33

A skin receptor cell that detects vibration

Front 34

Free nerve endings

Back 34

Pain and temperature

Front 35

Merkel's disc

Back 35

touch

Front 36

Meissner corpuscle

Back 36

touch

Front 37

Ruffini's ending

Back 37

stretch

Front 38

threshold

Back 38

The stimulus intensity that is just adequate to trigger a nerve impulse in the axon

Front 39

coding

Back 39

the rules by which action potentials in a sensory system reflect a physical stimulus

Front 40

range fractionation

Back 40

A hypothesis of stimulus intensity perception stating that a wide range of intensity values can be encoded by a group of cells. each of which is a specialist for a particular range of stimulus intensities

Front 41

somatosensory

Back 41

body sensation, referring to touch and pain sensation

Front 42

adaptation

Back 42

the progressive loss of receptor sensitivity as stimulation is maintained

Front 43

tonic receptor

Back 43

a receptor in which the frequency of nerve impulse discharge declines slowly or not at all as stimulation is maintained

Front 44

phasic receptor

Back 44

a receptor in which the frequency of nerve impulse discharge drops rapidly as stimulation is maintained

Front 45

sensory pathway

Back 45

the chain of neural connections from sensory receptor cells to the cortex

Front 46

thalamus

Back 46

the brain regions at the top of the brainstem that trade information with the cortex

Front 47

central modulation of sensory information

Back 47

the process in which higher brain centers, such as the cortex and thalamus, such as the cortex and thalamus, suppress some sources of sensory some sources of sensory information and amplify others

Front 48

receptive field

Back 48

the stimulus region and features that cause the maximal response of a cell in a sensory system

Front 49

primary sensory cortex

Back 49

for a given sensory modality the region of cortex that receives most of the information about that modality from the thalamus or in the case of olfaction, directly from the secondary sensory neurons

Front 50

secondary sensory cortex or non-primary cortex

Back 50

for a given sensory modality the cortical regions receiving direct projections from primary sensory cortex for that modality

Front 51

attention

Back 51

a state or condition of selective awareness or perceptual receptivity, possible involving the activation of certain brain regions

Front 52

primary somatosensory cortex (S1) or somatosensory 1

Back 52

the gyrus posterior to the central sulcus where sensory receptors on the body surface mapped. Primary cortex for receiving touch and pain information, in the parietal lobe

Front 53

secondary somatosensory cortex (S2) or somatosensory 2

Back 53

the region of cortex that recieves direct projections from primary somatosensory cortex

Front 54

polymodal

Back 54

involving several sensory modalities

Front 55

epidermis

Back 55

the outermost layer of skin

Front 56

dermis

Back 56

the middle layer of skin between the epidermis and the hypodermis

Front 57

hypodermis

Back 57

the innermost layer of skin, under the dermis

Front 58

dermatome

Back 58

a strip of skin innervated by s particular spinal root