brain and behavior exam 2 Flashcards
(195 cards)
1
Q
sensory systems
A
transduce environmental stimuli into action potentials
- operate to allow species to exploit ecological niches
- discriminate among forms of energy using specific receptors
2
Q
receptor cells
A
specialized cell that responds to particular energy or substance in internal or external environment- converts energy into change in electrical potential across membrane
3
Q
labeled lines
A
segregated neural pathways that each carries info about a distinct type of stimulus energy
-particular neurons labeled for distinctive sensory experiences
partially encodes stimulus quality
- receptor sends signal to particular line
4
Q
receptor potential
A
electrical change in receptor
- resembles excitatory postsynaptic potential
5
Q
sensory transduction
A
converting the signal from environmental stimuli to action potentials that brain can understand
6
Q
Pacinian corpuscle
A
onion like structure in innermost layer of skin- touch, mechanical force as energy
- selectively responds to vibration and pressure
- allows only vibrations more than 200 cycles per second, stretch part of neural membrane, open ion channels w entry of Na+, initiating action potential
- surrounds afferent nerve ending
7
Q
receptive fields
A
correspond to stimulus area that changes responses of a cell- both excitation and inhibition
- potential proportional to strength of stimulus, if potential exceeds threshold, action potential is generated
- shaped like donut with inhibitory inside, excitatory outside or vise versa, differ in size and shape
- specific for certain modalities (pain, cold, touch) tran
8
Q
meissner’s corpuscles and Merkel’s discs
A
mediate most of our ability to perceive forms of objects we touch
- merkels: edges and points
meissners: changes in stimuli, localized movement between skin and surface
9
Q
ruffini corpuscles
A
detect stretching of patches of skin when we move fingers/limbs
10
Q
free nerve endings
A
in the skin where pain, itch, heat, cold is detected
11
Q
receptive surface
A
displays plasticity- somatosensory representation of a region of the body changes if the corresponding region is injured or receives training
12
Q
levels of sensory processing
A
-sensory info enters CNS through brainstem or spinal cord to thalamus
- thalamus shares info with cerebral cortex; directs thalamus to suppress some sensations
-primary sensory cortex swaps info with nonprimary sensory cortex
13
Q
sensory info processing
A
selective and analytical
- selection analysis takes place along sensory pathways
- processing and filtering seen in many aspects of transduction
14
Q
somatosensory system
A
body sensation system
- reveals information by the position of receptors on sensory surface
- labeled lines help convey spatial info to directly encode
15
Q
sensory adaptation
A
progressive decrease in a a receptors response to sustained stimulation
- allows us to ignore unimportant events
16
Q
phasic receptors
A
- receptor where frequency of action potentials drops rapidly as stimulation is maintained
-display sensory adaptation - ex. somatosensory neuton
17
Q
tonic receptors
A
- receptor in which the frequency of action potentials declines slowly or not at all as simulation is maintained
-show little or no adaptation and can signal duration of stimulus - ex. pain receptor
18
Q
central modulation of sensory information
A
the brain actively controls the info it receives- helps brain attend to some stimuli more than others
19
Q
dorsal column system (touch)
A
- large wedge of white matter in dorsal spinal cord
-where somatosensory system sends sensory info thru CNS then to thalamus then to cortex (cortex directs thalamus to suprress some sensations)
20
Q
dermatone (skin- segment)
A
all levels of inputs organized according to a somatosensoty map, body is divided into descrete band
- touch, vision, hearing
21
Q
anterolateral (spinothalamic) tract (pain and temp)
A
sends sensory infro thru CNS to thalamaus to cortex to non primary
22
Q
thalamus
A
most sensory info reaches before being relayed to cortex, cortex also directs thalamus to suppress certain info
23
Q
primary sensory cortex
A
initial destination of sensory inputs to cortex
24
Q
nonprimary sensory cortex
A
cortical regions that may receive and process same info in collab w primary
- processes diff aspects of perceptual experience
25
primary somatosensory cortex
in postcentral gyrus, just posterioir to central sulcus, dividing parietal and frontal lobe
- touch info from opposite side of body
- size proportionate to density of receptors
26
brain regions
influence each other over time
- visual signal detected more accurately when accompanied by sound
27
association areas
sensory areas in the brain that process a mixture of inputs from different modalities
28
polymodal neurons
neurons that respond to other modalities
- convergence of indo from different sensory systems
29
synesthesia
stimulus in one sensory modality can evoke perception in another modality
- seeing a number evokes a color
30
plasticity
cortical maps are highly plastic, change as a result of experience
31
sensory homunculus
- representation of body parts along postcentral gyrus in parietal lobe
-over represents sensitive areas in the body
32
somatosensory pathways
touch
- unipolar neurons carry info to dorsal root ganglia and dorsal side of spinal cord thru white matter
- first synapse made in medulla/brainstem
- second neuron sends axon across midline in brain stem
- info goes to thalamus, to primary cortex
largely mechanical
33
pain pathways
chemical constituents from damaged tissue
4 synapses made from same neuron
nociceptors: pain receprots on free nerve endings
- detect chemicals, transduce them to action potentials
- action potentials move through dorsal root and column and carried within nerve but diff part
- multiple neurotransmitters involved: glutamate and substance p
- first synapse made in spinal cord
- spinal cord neurons send axons to thalamus but make pit stops to pons: vocalizing when injured, midbrain periaqueductal grey: activates analgesia system, thalamus
34
glutamate
tells you tissue damage occured
35
substance p
tells you how bad tissue damage is
36
cingulate cortex
where pain info is ultimately integrated
37
immediate short term pain
causes us to withdraw reflexively to prevent further damage
38
longer-lasting pain
encourages sleep, inactivity, recuperation
39
transient receptor potential vanilloid type 1
report rise in temp to warn of danger
40
transient receptor potential type Ms
detects higher temps but does not respond to capsaicin
41
A delta fibers
home of TRPM3 receptors
large, myelinated axons
- bc of diameter and myelination, they reach spinal cord quickly
42
C fibers
home of TRPV1 receptors
thin and unmyelinated
- longer lasting pain/sensations
43
anterolateral system
nerve fibers carry pain and temp info to dorsal horn of spinal cord, to spinal neurons, project across midline, then to thalamus, fiber release glutamate and substance p
44
cingulate cortex
part of limbic system
integrates pain info
- dif subregions mediate emotional vs sensory aspects of pain
- part activates when we empathize
45
neuropathic pain
pain that persists after injury started to heal
- ex phantom limb syndrome
46
gate control theory
theorizes that spinal gates control signal that gets through to brain
- suggests pain relief can be done thru finding ways to keep gates closed
47
analgesia
absence of pain
48
analgesic drugs
- highly effective in relieving pain
- opiate drugs bind to receptors to reduce pain
- over the counter meds
49
naloxone (narcan)
opiod antagonist
50
transcutaneous electrical nerve stimulation
mild electrical stimulation applied to nerves around injury site to relieve pain
- releases endogenous opioids
- may close spinal gate for pain
51
placebo effect
-simply believing they are receiving treatment can relieve pain
-can control pain in some people
- activate endogenous opioid system
52
endogenous opioid activation
activating endogenous opioids can relieve pain
- acupuncture; needle placement has little to do with pain, so expecting it does can relieve pain
53
movements
contractions of muscles that provide out sole means of interacting w the world
54
reflexes
simple, unvarying and unlearned responses to sensory stimuli- basic units of behavior
55
motor plan
complex set of commands to muscles established before an act occurs
56
electromyography
track simples movements that make up an act by recording electrical activity of muscles
57
primary and nonprimary motor cortex
receives info from cortical areas and sends to thalamus and brainstem
58
brainstem
passes commands from cortex to spinal cord
59
cerebellym and basal ganglia
adjust commands received from motor cortex
60
antagonists
diff muscles connected to bones by tendons are arranged in reciprocal fashion- when one muscle group contracts, it stretches the other group
61
synergists
muscles that work together to move limb in one direction
62
skeletal muscles
striped from overlapping layers of contractile proteins myosin and actin
- made of striate muscle
63
muscle fibers
slow twitch: contract with low intensity but fatigue slowly
fast twitch: contract strongly but fatigue quickly
64
motoneurons
- muscle contraction
-in spinal cord and brainstem and send action potentials along axon and axon collaterals to terminate at specialized synapses
- tend to have large cell bodies and dendritic fields
- potentials reach target quickly
- final common pathway: sole route where spinal cord and brain control muscles
65
neuromuscular junctions
specialized synapses where motor neuron action potentials terminate, actin and myosin slide past eachother
- located in muscle fibers
66
acetylcholin
neurotransmitter released by motor neuron
67
motor unit
motor neuron and all muscle fibers it innervates
- can involve thousands of muscle fibers
- can have few
68
proprioception
info abt body movements and positions
69
muscle spindle
type of propioceptors
- capsule buried within fibers of muscle that contains intrafusal fiber
stretch/length
70
intrafusal fiber
small muscle fibers that lie within each muscle spindle
71
golgi tendon organs
sensitive to tension of the muscle as it shortens
- detect overloads that threaten to tear muscles and tendons, can cause reflexive relaxation of affected muscles (knee jerk)
72
stretch reflex
contraction of muscle in response to stretch of the muscle
73
primary motor cortex
M1- major source of axons forming the pyramidal tract
- occupies precentral gyrus
74
precentral gyrus
immediately in front of central sulcus
- like a map of contralateral side of body
75
motor homunculus
representation of baody parts and correspondents along precentral gyrus of frontal lobe
76
nonprimary motor cortex
anterior to M1
- cortical regions that contribute to motor control
- behavior directly through communication w lower levels of motor hierarchy in brainstem and spinal cord, and indirectly thru M1
77
supplementary motor area (behaviors)
one of two regions of nonprimary motor cortex
- medial aspect of hemisphere
- recieves input from basal ganglia and modulates activity of primary motor cortex
- initiation of movement
78
premotor cortex (behaviors)
-anterior to primary motor cortex
- motor sequences guided by external events
-mosaic of diff units
79
plegia
paralysis
- damage to motor cortex
80
paresis
weakness
- damage to motor cortex
81
apraxia
inability to carry out complex movements
- damage to nonmotor zones of cortex ie parietal or frontal association cortex
82
pyramidal system
motor system w neurons within cerebral cortex and axons
- in cross section of medulla, wedge shaped, on each side of midline
83
extrapyramidal system
motor system w basal ganglia and brainstem structures
- projections pass thru spinal cord via reticular formation and red nucleus of midbrain and brainstem
84
extrapyramidal projections
motor fibers outside of pyramidal tracts
85
basal ganglia
- group of forebrain nuclei (caudate nucleus, globus pallidus, putamen)
- crucial for skill learning
-important source of extrapyramidal fibers
- receives infor from thalamus
-control amplitude and direction of movement
- movements performed by memory
86
cerebellum
located in back of brain dorsal to pons, involved in central regulation of movement and forms of learning
-important source of extrapyramidal fibers
- inputs come from sensory and motor systems like muscle and joint, vestibular, somatosensory, visual, auditory
87
ataxia
- loss of coordination of the legs
- result of damage to extrapyramidal motor structures- cerebellum
88
decomposition of movement
gestures broken up into individual segments instead of being executed smoothly- prob w gaze and visual tracking
- cause by cerebellar lesions
89
parkinsons
-progressive degeneration of dopamine-containing cells in substantia nigra
-disease that targets basal ganglia
90
substantia nigra
brainstem structure that innervates basal ganglia- source of dopaminergic projections
91
huntingtons
- destruction of basal ganglia results in syndrome of abrupt, involuntary movements and change in mental function
- caudate and putamen affected
92
auditory system
detects changes in vibration of air molecules caused by sound sources
- intensity and frequency
93
decibels
loudness
94
hertz
pitch
95
auditory transduction
outer ear directs sound to inner ear
- mechanical force of sound transduced into neural activity
96
amplitude
instensity of sound
97
frequency
pitch, number of cycles per second in sound wave
98
pinna (two pinnae)
funnel sound waves to ear canal
- mammalian
- placement aids in sound localization
99
ear canal
second part of external ear, leads to tympanic membrane
100
inner ear
cochlea nd vestibular apparatus
101
middle ear
cavity between tympanic membrane and cochlea
- volume control
tensor tympani and stapedius attach to chain of ossicles
- chain stiffens when sound hits and reduces effectiveness
102
tympanic membrane
eardrum- captures sound vibrations in air
103
ossicles
three small bones (incus, malleus, stapes) that transmit vibration across middle ear from ear drum to oval window
- concentrate and amplify vibrations
104
oval window
location on coclea at which vibrations are tranmitted from ossicles to interior of cochlea
105
cochlea
converts vibrational energy to neural activity
- size of a pea
spiral of canals
106
scala vestibuli
- one of three cochlea canals
107
scala media
one of three cochleal canals, contains organ of corti
108
scala tympani
one of three cochlea canals
109
organ of corti
receptor system that converts vibration into neural activity
110
hair cells
- auditory sensory cells, stereocilia proturude from top and transduce vibrational energy
part of organ of corti
111
basilar membrane
membrane in cochlea that contains principal structures involved in auditory transduction
-bridge between hair cells
112
tectorial membrane
-gelatinous membrane located on top of organ of corti
- hair cells are between
113
supporting cells
main structure of organ of corti
114
auditory nerve terminals
transmit neural signals to and from brain
-main structure of organ of corti
115
process of hearing
ossicles transmit vibrations to tympanic membrane to oval window
waves created in fluid of scala vestibuli
basilar membrane ripples- tapered so high freuqencies has greater effects at base and vice versa
116
stereocilia
sloping brush of miniscule hairs on upper surface of hair cell
- bridge between two membrance, bend when sound hits, causing ripple
- bend tightens tip links and causes depolarization of cell
rush of potassium and calcium
117
tip links
attached to each stereocilia
- open cation channels
118
inner hair cells
3500 in cochlea, single row
- closer to central axis of coiled cochlea
119
outer hair cells
12000 in cochlea in three rows
120
vestibulocochlear nerve
cranial nerve VIII, from cochlea to brainstem auditory nuclei
- fibers contact bases of hair cells
- convey info to brain
121
4 types of connections with hair cells
-IHC: afferent, to brain- 95% of fibers
-IHC: effetent- from brain
- OHC afferent- to brain abt state of basilar membrane
- OHC efferent- from brain, makes OHC change length, modifies stiffness of basilar membran regions
122
cochlear nucleaus
brainstem nuclei that receive input from auditory hair cells and send output to superior olivary nuclei
- where binaural interactions commence
123
superior olivary nuclei
brainstem nuclei that receive input from left and right cochlear nuclei and provide first binaural analysis of auditory info
- localizing sounds
124
inferior colliculi
paired gray matter structures of dorsal midbrain that process auditory info
125
medial geniculate nuclei
left and right, in thalamus and receive input from inferior colliculi and send output to auditory cortex
126
tonotopic organization
organization of auditory neurons according to an orderly map of stimulus frequency, low to high
- organization of cochlea to auditory cortex
127
primary auditory cortex (A1)
cortical region on superior surface of temporal lobe
- processes complex sounds transmitted from lower auditory pathways
128
place coding theory
theory that pitch of sound is determined by location of activated hair cells on length of basilar membrane
129
temporal coding theory
theory that frequency of auditory stimuli is encoded in rate of firing of auditory neurons
- mathematically related to cycles per second
- used with lower frequencies
130
hearing loss
moderate to severe decrease in sensitivity to sound
131
deafness
hearing loss so profound that speech cannot be perceived without hearing aid
132
conduction deafness
involves middle ear problem that blocks sound vibrations from reaching inner ear
133
sensorineural deafness
problem with structures- cochlea- that convert sound vibrations into neural activity and project to brain
- ripples in badilar membrane fail to convert
134
central deafness
damage to auditory brain structures can affect hearing in various ways
135
word deafness
selevtive trouble with speech sounds despite normal speech and hearing
136
cortical deafness
rare- involves bilateral lesions of auditory cortex
137
superior olivary nuclei
compare intensity and latency differences between ears to localize sound
138
flavors
sense of taste combined with sense of smell
139
tastes
salty, sour, sweet, bitter, umami
- determined genetically
140
taste buds
clluster of 50-150 cells that detect tastes
- found in papillae
141
papillae
lumps of tissue that increase surface area of the tongue
- contain most receptor cells
142
3 types of papillae
- circumvallate: back part, mostly bitter
-foliate: middle, sweet sour salty and bitter
-fungiform: front, umami salty
143
microvilli
fine fibers that extend from taste receptor cells into tiny pore where they come into contact with tastants
144
tastant
substances that can be tasted
145
taste receptor cells
10-14 day lifespan
146
g protein
perceive sweet, bitter and umami
147
salty
ionotropic Na+ ions
148
sour
ionotropic H+ ions
149
sweet, bitter
metabotropic receptors
- tastant molecules bind to complex receptor protein on taste cell surface
- bitter signals toxins
150
umami
metabotropic glutamate, heterodimer of T1R1 and T1R3
151
gustatory system
sensory system that detects taste
- extends from tongue to brainstem nuclei to thalamus to sustatory regions of somatosensory cortex
152
olfaction
odor perception
153
odors
sensation of a smell
- can discriminate btwn 1 trillion odors
154
olfactory epithelium
sheet of olfactory receptors and cells that lines dorsal portion of nasal cavities and adjacent regions
155
olfactory receptor cell
complete neuton with dendrite and cilia that extend to mucosal surface
- odorant dissolve in mucosal layer and interact with receptors
- variety of G protein
- can regenerate
156
olfactory bulb
anterior projection of brain that terminates in upper nasal passages thru small openings of skil, provides receptors for smell
157
glomerulus
spherical clump of neurons
-arbor of dendrites from group of olfactory cells
- receives inputs exclusively from olfactory neurons
- tunes and sharpens neural activity
- receive signals from cilia
158
olfactory cilia
dendrite that divides into branches on olfactory receptor cell
- extend into olfactory mucosa and project unmyelinated axons
159
mitral cells
convey olfactory info to brain
160
odorant receptor genes
humans-350
mice-1000
161
chemical senses
olfactory and gustatory systems
162
smell
only sensory modality that synapses directly in cortex rather than going thru thalamus
163
olfactory system pathway
-olfactory receptors to amygdala, prepyriform cortex and hypothalamus
-amygdala to hypothalamus and medial dorsal thalamus
- prepyriform cortex to hypothalamus and medial dorsal thalamus
- hypothalamus to lateral posteriot orbitofrontal cortex
- mefial dorsal thalamus to orbitofrontal cortex
164
vomeronasal organ
collection of specialized cells near olfactory epithelium that detects pheromones and sends signals to olfactory bulb
165
retina
layer of neurons that turns light into neural signals in a transduction process
- frist stage of visual info
166
cornea
outer layer of eye with fixed curvature
- blends light rays and is responsible for forming image on retina
167
refraction
bending of light rays
- visual info refracted and turned to back of eye
168
lens
helps focus image on retina
- shape indicates where light hits
- cyndrical when focused on something near, flat when focused on something far
169
ciliary muscles
controls change in shape of lens
- contraction of muscle alters focal distance of eye causing accomodation
170
accommodation
process by which ciliary muscles adjust lens to bring nearby objects into focus
- focuses light on fovea
171
myopia
difficulty seeing distant object
- develops if eyeball is too long, causing corna and lens to focus in front of retina instead of on retina
172
fovea
focuses light to bring acuity
- cones concentrated in this area
- not as sensitive
- needed to have clear view of world
173
ectraocular muscles
three pairs of muscles extend outside of eyeball to bony socket of eye
- controls position and movement of eye
174
photoreceptors
sensory neurons that detect light
175
rods
photoreceptor in retina that is most active at low levels of light
- humans have 100 million
- outside fovea, large so acuity is lower
- slow
176
cones
photoreceptor cell in retina responsible for color vision
- concentrated in fovea, small so acuity is higher
- humans have 4 million
-rapid
177
bipolar cells
- receives info from rods and cones and passes to retinal ganglion cells
-rod and cone phororeceptors release neurotransmitter into bipolar cell synapses
- connect with ganglion cells
178
ganglion cells
cells in retina whose axons form optic nerve
179
optic nerve
cranial nerve II
- collection of ganglion cell axons that extends from retina to brain
- carries info to brain
180
horizontal cells
retinal cell that contacts photoreceptors and bipolar cells
181
amacrine cells
specialized retinal cell that contacts bipolar and ganglion cells- inhibitory interactions in retina
182
anatomy of retina
cells generate graded local potentials, no action potentials
- ganglion cells conduct action potentials
183
scotopic system
system in retina that operates at low levels of light and involves rods
- use to detect objects in dim light
- has a lot of convergence bc many rods converge onto each ganglion cell
184
photopic system
system in retina that operates at high levels of light, sensitive to color, involves cones
- less convergence
185
rhodopsin
photopignment in rods that responds to light
- light particles that strike discs
-triggers a cascade of chemical reactions that close sodium channels, result in graded
hyperpolarization and associated decrease in transmitter release (from tonic levels), signaling a
change in illumination
186
pupil
opening, formed by iris that allows light into eye
- adjust sin size to deal with large range of light intensities
187
iris
colorful disc that provides opening for pupil
188
visual field
area that you can see without moving head or eyes
189
visual acuity
sharpness of vision
190
optic chaism
-where parts of two optic nerves crosses at midline
191
nasal hemiretina
where axons from half of retina move toward nose
- right to right, left to left
192
temporal hemiretina
projects axons on its own side of brain
- right to left, left to right
193
lateral geniculate nucleus
part of thalamus that receives info from optic tract and sends to visual areas in occipital cortex
194
visual info pathways
ptic nerves to optic chiasm to lateral geniculate nucleus (LGN), visual cortex
At successively higher levels of the visual
system, the receptive fields of neurons become larger and respond to more complex stimuli.
195
two streams
ventral: what- recognition of objects
dorsal: where- location of objects
