Final exam Flashcards
1
Q
what Provides basic wiring of the brain’s circuitry
A
synaptic plasticity
2
Q
in what is synaptic plasticity involved in?
A
Memory
Learning
Rehabilitation
3
Q
until what age are synapses continued to be made in the brain
A
until 2 years old
4
Q
what are the different mechanisms of brain plasticity available to the young CNS
A
1) Growth of axons and dendrites
2) Pruning of branches
3) Creation of synapses
4) Death of neurons
5) Changes in synaptic strength (LTP)
5
Q
What is the critical period when talking about neuroplasticity?
A
maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli
6
Q
what test was conducted to determine the importance of the critical period in child development?
A
monocular deprivation lead to development of vision in only one eye
7
Q
how is neuroplasticity involved in learning
A
help to adapt an individual’s brain according to the relative amount of usage and functioning
8
Q
what is learning?
A
Change in behavior that results from acquired knowledge about the world
9
Q
what is memory?
A
Process by which that knowledge in encoded, stored and later retrieved
10
Q
what can be remembered with memory?
A
People & places
Language
Motor skills
Personal identity
11
Q
in cases of injury what may happen to the sensory or motor maps?
A
they may be remapped to adapt to new pathways
12
Q
in the case of amputation to the sensory maps?
A
the map occupied by the missing body part is now a map of the adjacent finger
13
Q
what are some terms associated to neuroplasticity in adults?
A
Reorganization Learning Memory Adaptation Functional recovery Recuperation Rehabilitation
14
Q
why does axon regeneration in the CNS fail?
A
environment surrounding CNS lesions is inhibitory to axon growth
most CNS axons only mount a feeble regeneration response after they are cut
15
Q
what was hypothesized in hebb’s postulate?
A
coordinated activity of a presynaptic terminal and a postsynaptic neurons strengthens the synaptic connection between them
16
Q
what is explained by hebb’s postulate?
A
the cellular basis of memory and learning
17
Q
what are the different forms of short term plasticity?
A
facilitation
augmentation
potentiation
depression
18
Q
what is the timescale associated with short term plasticity?
A
tens of milliseconds to a few minutes
19
Q
what is affected in short term plasticity?
A
the amount of neurotransmitter released from presynaptic terminals in response to a presynaptic action potential either increase of decrease
20
Q
what is short term plasticity caused by?
A
persistent actions of calcium ions within the presynaptic terminal
21
Q
what are the main factors associated with long term plasticity?
A
strengthens synapses
basis for changes in brain functions that last weeks, months, years
underlies behavioral modification
22
Q
how does long term potentiation happen?
A
Few seconds of high frequency electrical stimulation can enhance synaptic transmission in the hippocampus for day even weeks by producing changes in the synapses
23
Q
what happens to a single stimulation after a strong activation?
A
increase EPSP.
24
Q
who described LTP? and when?
A
Described in 1973 by Terje Lømo and Tim Bliss
25
LTP required the binding of what NT to what type of receptor?
binding of glutamate to NMDA receptors
26
what happends suring postsynaptic depolarization in LTP?
Glutamate binds to NMDA receptor thus expelling Mg2+ from the channel and allowing Ca2+ to enter
27
what timescales are associated with longterm forms of plasticity?
30 minutes of longer
28
long term forms of plasticity arise from what?
Post-translational modifications of existing proteins, most notably changes in the trafficking of glutamate receptors
29
what are changes produced during later phases of LTP?
gene expression changes
30
in what regions of the brain can LTP be seen to happen?
amygdala, cerebellum and cerebral cortex`
31
Growing and adapting quality of dendritic spines that provide the basis
Synaptic plasticity and learning and memory
32
what is habituation
simple form of short term memory that allows our body to habituate to certain stimulis (touch, smell, etc) which at first we feel but then get used to
33
what is sensitization
simple form of long term memory
| its the generalization of an aversive response elicited by a noxious stimulus to a variety of non noxious stimulus
34
what is short term memory?
its is quickly acquired but quickly forgotten
useful for immediate recell
assess speech and visuospatial info
35
what type of memory is associated with changes in neural firing pattern and neuromodulator/transmitter release?
short term memory
36
what are the properties of long term memory?
slow process but long lasting
37
what type of memory is associated with plastic changes in the brain (number and strength of the synapses)
long term memory
38
the vestibular system Process sensory information underlying motor responses
Self-motion
Head position
Spatial orientation relative to gravity
Helping to stabilize gaze, head and posture
39
the vestibular system is important for the evaluation of what type of injury?
injury at the brainstem
40
what bone composes the vestibular system?
temporal bone
41
what is the function of the semicirular canal?
provides information about rotational acceleration
42
where are the hair cells of the vestibular system responsible for?
allow to detect motion and send AP to the cortex and cerebellum
43
vestibular N is a branch of what CN?
CN 8
44
what fluid fills the vestibular system?
endolymph which is high in calcium
45
where are vestibular cells located?
ampulla
46
what is contained in the otolith organ
utricle and saccule
47
what is the fluid that fills the membranous sacs in the vestibular system?
endolymph
48
what are the longer hair cells called?
kinocillium
49
what are the shorter hair cells called?
sterocillia
50
what happens in the case that the movement of the endolymph strikes the haircells in the direction of them?
it allows the channels to open and release Ca2+ therefore increasing the amount of APs that are fired (more depolarizedP
51
what happens in the case that the movement of the endolymph strikes the haircells in the opposite direction of them?
haircells are not deflected therefore the cell hyperpolarizes and reduces the amount of APs that are fired
52
what is the name of the cristals that float in the endolymph?
otoconia
53
what is the function of the otoconia?
it will pull on the liquid and hair cells in a given direction
54
what happens to the otoconia in cases of TBI?
the calcium crystals may be displaced and will move around causing imbalances leading to vertigo
55
how many kilocilium does each hair cell
one
56
what hair cell is responsible for the mechanical openning of channels?
kinocilium
57
what happens when hair cells bend towards kinocilium?
neuron activity increases
58
what happens when hair cells bend away from kinocilium?
neuron activity decreases
59
what organ is responsible for horizontal acceleration?
utricle
60
what organ is responsible for vertical acceleration?
saccule
61
what is sensed by the semicircular canals?
rotation
62
what heppens if hair cells in the semicirular canal are hit in ther preferential direction?
increases AP firing
63
how do the semicirular canals lie?
in 3 planes
64
the vestibular system is in constant communication with what portion of the brain?
cerebellum
65
how does the vestibular system undergo multisensory processing?
it projects to different structures such as eyes, neck, limbs to ensure balance and control motion
66
what vestibular reflex directly synapses on the cerebellum?
vestibulo-occular reflex
67
what is the vestibulo-occular reflex?
involves the reflexive ete movement that counter head movemtn so that gaze is fixed
68
at what speed does the vestibulo-occur reflex occur?
5 ms
69
what acts as a premotor cortex for the occulomotor and abducens nerve
the vestibular nuclei
70
what nucleus is reached by the vestibular-cervical reflex?
MEDIAL VESTIBULAR NUCLEUS
71
what does the VCR respond to?
semicircular canal and responds to movement of the head
72
what nucleus is reached by the vestibulospinal reflex?
REACHES THE LATERAL VESTIBULAR NUCLEUS
73
through what tract does the VSR travel?
lateral vestibulospinal tract
74
what is contoled by the VCR?
movement of the head
75
what is controlled by the VSR?
movement of the body
76
in what cases does decerebration occur?
in cases of lesions above the vestibular system
77
what is associated to the decerebration?
fully extended posture
78
what is suggested by decerebration?
that the cerebral corthex nromally supresses the VS pathway
79
what is the vestibular pathway to the thalamus involved in?
in perception of body orientation in extrapersonal space
80
what happens if we have a lesion in the right parietal lobe?
left hemineglect syndrome
81
what portions of the thalamus recieve information from the periphery and vestibular system that gets sent to S1?
VPM and VPL
82
how much of our life is consumed by sleep
1/3
83
Does sleep occur in all mamals?
yes
84
is sleep associated with a decrease in brain activity
no
85
why is sleep impoortant
consolidates memory and learning retention
86
what is the role of sleep and glycogen
replensihed glycogen levels
87
what is the relation ebwteen sleep and energy conservation
temperature regulation,
88
what happens if we lack sleep
decreased memory and cognitive ability, mood swings hallucination
89
can we die from lack of sleep
yes
90
what hormone triggers sleep? when does it peak?
melatonin
| peak at 2-4am
91
what is responsible for percievable light changes
melanopsin contained in the photoreceptors
92
information provided from melanopsin is sent to what portion of the brain?
hypothalamus
93
how is melatonin secretion inhibitied?
the presence of light captured by melanopsin signals pre-G sympathetic neurons which signal the pinealgland and prevents melatonin secretion
94
what type of assessments about vision can be made by an optometrist?
Visual acuity, near and far
Visual fields
Binocular vision
Colour vision
95
his hemineglect a visual or a cortical disorder?
cortical --> damage to the parietal lobe
96
what are the different photoreceptors contained in the retina?
cones and rods
97
onto what do cones and rods synapse onto?
bipolar cells
98
what type of cells are found below the rods and cones in the visual pathway?
ganglion cells
99
what do the ganglion cells form?
the optic nerve
100
what types of cells increase contrast sensitivity
horizontal and amacrine cells
101
do photoreceptors produced APs?
no
102
what is steadily released by the photoreceptors in the dark?
NTs
103
what happens to the photoreceptors in the presence of light?
the photoreceptors hyperpolarize and amount of NTs released is reduced.
104
how do rods synapse on bipolar cell?
multiple on one bipolar cell
105
how can rods be described?
more sensitive to light, lower acuity
function well in the dark as the signal gets amplified
big RFs
106
how do cones synapse on bipolar cell?
one on one
107
how can cones be described?
higher acuity but lower light sensitivity, better for spatial sensitivity.
108
what photoreceptor is more concentrated in fovea and responsible for color vision and acuity?
cones
109
what type of RF do ganglion cells have?
center surround
110
what does center surround RF represent?
the central and surrounding area of the RF have opposite properties
111
when do center cells “on” produce APs
when light is shined in the center of the RF
112
when do center cells “on” not produce APs
when light strikes the surround area
113
when does the surround area produce AP?
when light hits the center
114
what causes the contrasting RF in center surround RFs
Due to inhibitory properties of horizontal cells which make synapses with different bipolar cells and photoreceptors
115
how is light generally recieved in the real worl?
we do not receive small dots of light on single receptive fields
116
when is the ganglion cell most responsive?
when the center is lightened up and surround is dark
117
what do ganglion cells respond to best?
visual corners, contrasts, edges, etc
118
what type of map is contained by the visual system?
retinotopic map
119
up to where does the retinotopic map extend?
striate cortex
120
what do ganglion cells project onto?
lateral genticulate bodues and superior colliculus
121
onto what do the lateral genticulate bodies project onto
striate cortex
122
what type of movement is controled by the superior colliculus?
reflexes and eye movements
123
what type of vision occupies a large volume of Lateral genticulate bodies?
central vision
124
how is the image on the retina?
inverted
125
how is the lateral genticulate body organized
in multiple layers in both eyes, each of which is organized as a map of the retina
126
what happens when the axons comming from both etes are combined in the lateral genticulate body?
they combine but remain segregated
127
onto what area do axons leaving the LGB project onto
straite cortex (area 17_
128
in the cortex the inputs from both eyes are combined into what?
dominance columns`
129
dominance columns are more responsive to what?
visual inputs from the left or right eye
130
what type of pattern is observed in the dominance columns
```
adjacent colums are testes
a- contralateral eye
b- both eye
c- ipsilateral eye
pattern repeates
```
131
what is the cytoarchitectonic region 17 known as
primary visual cortex
132
what happens in the case of a lesion in the occipital pole
destruction of a portion of the retinal representation
133
what do neurons in the striate cortex respond to?
orientation
134
what do neurons respond to in the LGN
EDGES AND CONTRASTS
135
how are edge orientations distributed within the striate cortex?
equally
136
what is the organization within the same cortical column in the striate cortex?
neurons have roughly the same receptive field, the same ocular dominance and the same orientation preference
137
how are neighboring columns organized in the striate cortex?
may have different receptive field, ocular dominance and/or orientation preference
138
columnar origanization for light causes what type of neural response?
neurons respond to elongated bars of light
139
what is the diameter of the cortical column?
0.5mm
140
where do cortical columns rnage from?
Stretches from white matter to cortical surface
141
what do the cortical columns consist of?
Consists of neurons activated by one class of receptors
142
what is the function of the different visual areas ?
all believed to have different functions
143
what is the role of the middle temporal area in te extrastriate cortex?
responds to moving edges
144
what is the role of visual area 4?
color perception
145
how are the axons of the olfactory system?
short unmyelinated axons
146
onto what do the olfactory receotor neurons project onto?
neurons in the olfactory bulb
147
how does humans smell compare to rats?
humand dont have the bets sens of smell. they have approximately the same amount of olfacotry neurons as rats however the space occupied by the neurons in the brain is much larger than in rats and therefore sense is much less developed
148
what was the first sens detected?
smell
149
what part transduces the signal for smell?
the snesory neuron itself
150
how many different types of smell sensory neurons do humand have?
400 different or more
151
where does transduction of smell occur?
transduction of olfactory receptor cells in olfactory epithelium
152
how are the smell sensory neurons described as?
bipolar cells with dendrites/cilia on the surface of the epithelium
153
what do the receptors in the cilia possess?
they have cilia that have channels that bind to specific odor molecules which triggers and AP
154
what does mucus serve as?
mechanical trap for the odorate molecule
155
what is particular about olfactory neurons?
they can constantly be remplaced as they remian stem cells throughout their entire life
156
what are the main cells found in the olfactory bulb?
mitral cells and glomeulus
157
onto what do axons of the olfactory receptor synapse on?
mitral cells
158
what forms the glomerulus?
the synapses of the mitral cells in the olfacotry bulb
159
what composes a glomerulus
One glomerulus: dendrites from ~25 mitral cells and axons from ~25,000 ONR axons
160
what is the glomerulus sensiive to?
one specific odorant. this creates an odorant map
161
what is formed by the arrangement of the glomerului?
an odorant map which enables us to recognize and associate different odors
162
olfactory signals have connections to what?
Olfactory signals have powerful connections to cortical and subcortical areas.
163
what can be evoked by olfactory signals>
memories (hyppocampus) and emotions (amygdala)
164
how can epiliepsy be trigged by smells?
strong smells may trigger this due to its association with different portions of the brain
165
what is the orbifrontal cortex associated with?
peronality
166
what is the similarity between taste and smell?
both detect chemicals in the environment
167
what provides innervation to the anterior 2/3 of the tongue
corda tympani a branch of facial N
168
what does the glossopharygeal N innervate?
sensation of taste to the posterior 1/3 of the tongue
169
where does the first taste synapse occur?
in the nucleus of the solitary tract
170
where is the nucleus of the solitary tract located?
in medulla oblongata
171
what gets depolarized by taste receptors?
they depolarize gustatory neurons
172
where are the gustatory neurons contained?
taste buds
173
what type of receptors are gustatory neurons?
chemoreceptors
174
what carries the taste molecules to the receptors in the tongue?
saliva
175
what are the 5 classes of stimuli detected by taste sensation?
```
sweet
salty
bitter
sour
umami
```
176
how is the acitvation of gustatory neurons based on different tastes?
different tastes will activate different neurons
177
what is umami taste?
a taste sensation that is meaty or savory and is produced by several amino acids and nucleotides (such as glutamate and aspartate)
178
how do gustatory messages travel to the brain?
travel through the BS to the thalamus and to the cortex
179
how many neurons are needed for taste to reach the cortex
3
| bs --> thalamus --> cortex
180
where is the gustatory sense detected in the cortex?
in the frontal cortex and insula
181
onto what does the solitary tract synapse on
VPM of thalamus --> frontal cortex
amygdala
hypothalamus
182
what can be used to measure hearing loss?
audiogram which allows to detect the minimal threshold of spound able to be heard
183
which type of frequency (high or low) travel further?
low frequency
184
what frequencies are generally lost with loss of hearing?
high frequencies
185
what happens to sound as it enters the round window? why?
sound gets amplified because of the changes in pressure
186
what happens as the sound passes into scala vestibuli and scala tympani?
shearing between basilar and tectoral membrane which causes deflection of hair cells
187
what is the function of the round window?
allows to move liquid back and forth, if a pull is exerted then it will yield a push motion and vice versa
188
where does sound transduction occur?
in the organ of corti
189
how does sound transduction occur?
the pressure wave moves the basilar membrane and hair cells the cilia are fixed to the tectoral membrane resulting in shearing forces which opens transmembrane channels and creates back and forth bending of hair cells on the tectoral membrane
190
what do the generated sound potentials generate int eh auditory nerve?
AP in the nerve
191
what forms the organ of corti?
Organ of Corti: hair cells + tectorial membrane + basilar membrane + other supportng cells
192
where do hair cells sit on>
basilar membrane
193
onto what do hair cells synapse on?
with sensory neurons found in the spiral ganglion
194
what do spiral ganglion cells project onto?
onto the cortex and form CN 8
195
what is the sens organ for hearing?
organ of corti
196
how are the hair cells divided into?
inner and outer
197
what is provoked by the shearing motion
bending of hair cells and production of receptor potential
198
what is converted by the inner hair cells?
the mechanical shearing is converted to neural activity
199
what happens when the sterocilia on inner hair cells are bent?
opens the ion channels
200
what does the flow on K+ into hair cells release/
transmitter substance for hair cells and produces a generator potential in the sensory neirons of the spinal ganglion
201
AP travel where to generate sounds
in the CNS to afferent neurons
202
what type of signal is recieved from outter hair cells?
signal from efferent neurons
203
what type of information is carried by efferent neurons in auditory system?
carry information from higher auditory system to cochlea
204
where do the efferent neurons of the auditory system come from?
superior olivary complex
205
what is the function of the efferent neurons of the auditory system?
sharpen the tuning of the inner hair cells.
206
are outter hair cells sensory neurons?
no, they recieve information.
207
what is the function of the outter hair cells?
they are believed to modulate the function of inner hair cells and make it much less sensitive to different sounds
208
hwo are sounds converted to nerve impulses
cochlea will convert sound tone to movement of a portion of the basilar membrane and movement of a specific place activates a specific set of hair cells which activates a specific group of neurons and the neurons project to a specific place in the CNS maps of the auditory system
209
what do the auditory maps represent?
a specific location represents a specific sound frequency
210
what is tone?
a specific frequency of sound
211
what do different frequncies produce in the basilar membrane?
different sounds produce movement of different portions of the basilar membrane allowing different group of neurons to signal different frequencies
212
what do frequencies show in the auditory cortex?
selectivity
213
what is unique to each auditory neurone
each have a characteristic frequency which is the frequency at which the threshold of the axon is at its lowesr
214
what is the basis of tonortropic organization?
frequency selectivity
215
what is the most common cause of hearing loss?
damage to the inner hair cells
216
what are the main factors of inner hair cell damage
repeated exposure to loud noises
aging
heredity
217
what does our ability to localiize sounds depend uoin
upon the interaction of information from two ears. Those interactions seem to occur at many levels beyond the cochlear nuclei.
218
give an example of a binaural perception?
our ability to localize sounds
219
what are the key brainstem nucleis involved in the auditory system
cochlear nucleus
superior olivary nucleus
inferior colliculus
MGB
220
what are the main functions of the auditory nucleis
reflex and orienting functions
221
what is the first relay nucleus of the auditory system?
cochlear nucleus
222
what is the function of the cochlear nucleus?
preserve and enhance frequency information
223
what type of neurons are contained in the superior olivary complex?
binaural neurons
224
how is the superior olivary complex an example of binaural interaction?
the inputs from the two ears converge on the same neuron, but with different time delays dur to distance.
225
what is the main fucntion of the superior olivary complex?
Has a role in sound localization based on the use of timing and intensity differences between the two ears. Translates speed of conduction as a delay and delay is then interpreted a an angle
226
inferior colliculus recieves information from where>
from the olivary complex and the cochlear nucleus.
