mod 2 Flashcards
1
Q
rostral
A
anterior
2
Q
caudal
A
posterior
3
Q
dorsal
A
superior
4
Q
ventral
A
inferior
5
Q
lateral
A
toward the side
6
Q
medial
A
toward the midline
7
Q
ipsilateral
A
on the same side
8
Q
contralateral
A
on the opposite side
9
Q
longitudinal fissure
A
separates the two hemispheres
10
Q
lateral sulcus
A
separates the temporal lobe from the frontal and parietal
11
Q
central sulcus
A
separates the frontal and parietal lobes
12
Q
temporal lobe gyri
A
superior, middle and inferior
13
Q
parietal lobe gyri
A
postcentral gyrus, superior and inferior parietal lobule
14
Q
frontal lobe gyri
A
precentral gyrus, superior/middle/inferior frontal gyrus
15
Q
what separates the superior parietal lobule from the inferior parietal lobule
A
intraparietal sulcus
16
Q
main fibre tract connecting the two cerbra
A
corpus callosum
17
Q
large structure attached to dorsal aspect of the brain stem
A
cerebellum
18
Q
subcortical structures
A
thalamus, basal ganglia
19
Q
brainstem
A
midbrain - pons - medulla
20
Q
basal ganglia
A
caudate nucleus + lentiform nucleus (putamen + globus pallidus)
21
Q
where are superior and inferior colliculi found
A
midbrain
22
Q
make up of ventricular system
A
consists of interconnected cavities filled with CSF
23
Q
divisions of ventricular system
A
2 x lateral, third and fourth
24
Q
what separates the lateral from the third
A
interventricular foramen
25
what separates the third from the fourth
cerebral aqueduct
26
white matter
axons, myelin
27
grey matte
cell bodies
28
10% of brain cells
neurons
29
90% of brain cells
glial cells
30
myelin
fatty substance that surrounds and insulates nerve fibres
31
destruction of myelin causes
multiple sclerosis
32
fMRI
records changes related to metabolic activity in order to produce a functional view of the brain
33
how many neurons are thought to be involved in representation of a single image
two hundred million neurons
34
brain lesion analysis
comparing people with brain lesion in region of interest with people whose region is intact
35
EEG
records brains electrical activity
36
ERP
a signature of the electrical activity (recorded by EEG) occurring in brain in response to specific event
37
ERP considers electrical response for three events
latency, amplitude + polarity, scalp topography
38
ERP temporal and spatial resolution
spatial not accurate, temporal accurate
39
structural neuroimaging
CT, MRI, DTI
40
functional neuroimaging
PET and fMRI
41
uses x-ray technology to produce a series of brain images enabling the structure of the brain to be viewed
CT
42
produces brain images with higher resolution than CT
MRI
43
provides view of white matter tracts using MRI scanner
Diffusion tensor imaging
44
provides image of concentration/distribution of the radioactive substance
PET
45
which has greater spatial resolution fMRI or PET
fMRI
46
records changes related to metabolic activity in successive images in order to produce functional view of brain
fMRI
47
non-invasive method that causes transient disruption of brain activity by emitting a brief magnetic pulse.
Transcranial magnetic stimulation TMS
48
TMS excitatory or inhbitory
can be either
49
a prominent fold of cartilage-supported skin, captures sound and focuses it into the auditory canal
pinna
50
where does auditory canal end
eardrum
51
outer ear components
pinna and auditory canal
52
outer ear
sound waves are captured by pinna and focused into auditory canal
53
middle ear components
ear drum (tympanic membrane) and ossicles
54
ossicles
incus, stapes, malleus
55
high pressure region does what to ear drum
pushes it inward
56
low pressure region does what to eardrum
pushes it outward
57
how are vibrations caused within ear
constant low and high pressure pushing eardrum in and out
58
vibrations travel from eardrum to ossicles to
cochlea
59
cochlea
spiral shaped fluid filled tube
60
where are hair cells
cochlea
61
what converts the sound signal to mechanical vibrations
the ossicles from the vibrations
62
what converts the mechanical signal to an electrical signal
hair cells
63
where do hair cells synapse
spiral ganglion cells
64
tinnitus
person hears noises in absence of any sound stimulus
65
how is tinnitus caused
by disease processes affecting cochlea or auditory nerve or spontaneous activity
66
inner ear to CNS
spiral ganglion cells --> vestibular nerve - vestibulocochlear nerve.
67
vestibulocochlear nerve
carries both balance (vestibular nerve) and hearing (auditory nerve) from cochlea to brain stem
68
auditory signal synapse where in brainstem
cochlea nuclei located at level of lower pons and upper medulla
69
auditory information from cochlear nuclei to where?
inferior colliculi to medial geniculate nucleus of thalamus to primary auditory cortex
70
auditory pathway in brain
cochlear nuclei - inferior colliculi - medial geniculate nucleus - primary auditory cortex
71
where is primary auditory cortex located
superior temporal lobe
72
hechls gyri
primary auditory cortex
73
tonotopic organisation
in primary auditory cortex
74
interaural time
difference in arrival time of sound at the ear
75
where is sound localisation not good
vertical plane
76
what produces the reflections of entering sound
bumps and ridges on outer ear
77
sound waves are captured by the pinna and focused into the auditory canal
external ear
78
sound waves strike the ear drum and the vibrations pass through the ossicles to the cochlea
middle ear
79
hair cells within the cochlea transduce the vibrations into a neural signal, which is sent to spiral ganglion cells, whose axons form the cochlear nerve which carries info to brain stem via vestibulocochlear nerve
inner ear
80
where is medial geniculate nucleus found
thalamus
81
the opening that allows light to enter the eye and reach the retina
pupil
82
a circular muscle that controls the size of the pupil
iris
83
the transparent surface that covers the pupil and iris
cornea
84
the white of the eye, continuous with cornea
sclera
85
helps focus ray of light on the retina
lens
86
the internal lining of the rear two-thirds of the eye; converts images into electrical impulses, which are sent to the brain
retina
87
the central area of the retina that is specialised for the central vision
macula
88
marks the centre of the retina and the centre of the macula
fovea
89
visual image is the least distorted
fovea
90
made up of the axons of retinal ganglion cells, carries impulses for vision from the retina toward the brain
optic nerve
91
wavelength of electromagnetic energy that is visible to the naked human eye
400-700nm
92
flow of information within the retina
photoreceptors -> bipolar cells -> ganglion cells
93
photoreceptors
rods and cones
94
displacement of bipolar and ganglion cells
laterally to allow light to strike foveal photoreceptors directly
95
rods
scotopic, poor acuity achromatic vision in low light
96
photopigment in rods
all the same
97
periphery heavy in rods or cones
rods
98
cones
photopic, high acuity colour vision
99
central retina / fovea heavier in cones or rods
cones
100
photopigment of cones
different cones sensitive to different wavelengths of light
101
blindspot
where the axons of retinal ganglion cells exit retina, there are no photoreceptors
102
total amount of space that can be viewed by retina
visual field
103
half the retina that is closer to the nose
nasal hemiretina
104
other half of the retina (not close to the nose)
temporal hemiretina
105
blindspot location
15 degrees eccentric in your temporal hemifield
106
where is optic disc located in retina
nasal hemiretina
107
axons in which hemi-retina cross the midline
ganglion cells in the nasal hemi-retina
108
when visual stimuli in the right hemifield
cells in both retinas project axons into left optic tract
109
if left optic nerve is cut
vision in left eye will be lost completely
110
if optic chiasm is transected
peripheral vision will be lost bilaterally
111
if left optic tract is cut
vision fo right hemifield will be lost bilaterally
112
axons of ganglion cells pre optic chiasm
optic nerves
113
axons of cells post optic chiam
optic tract
114
axons of optic tract project to
superior colliculus and lateral geniculate nucleus in thalamus
115
subcortical vision
retinotectal pathway
116
retinotectal pathway
retina, superior colliculus
117
cortical vision
retinogeniculostriate pathway
118
retinogeniculostriate pathway
retina, thalamus (LGN), primary visual cortex
119
superior colliculus in non-mammalian vertebrates
optic tectum
120
% of ganglion cells in retina that project to superior colliculus
10%
121
% of ganglion cells that project to the lateral geniculate nucleus
90
122
what does the right lateral geniculate nucleus receive information about
the left half of the visual field
123
what does the left LGN receive information about
the right half of the visual field
124
primary visual cortex location
medial part of occipital lobe buried within the calcarine fissure
125
visual pathway from primary visual cortex
to striate cortex -> V1 -> broadmanns area 17
126
what happens when TMS is placed over the occipital cortex
TMS can elicit light sensations (phosphenes) in absence of any visual stimuli
127
increase in the phosphene threshold reflects..
reduced visual cortex excitability
128
reduction in phosphene threshold reflects
increased visual cortex excitability
129
correlation of ecstasy use and phosphene threshold
negatively correlated
130
phosphene levels in mdma users and control
ecstasy group had lower threshold than control, those who hallucinated within ecstasy group was even lower
131
where does sensory integration occur
heteromodal regions of cortex
132
superior colliculus visual or auditory
both! but think visual
133
what does ventriloquist illusion provide
an example of how visual and auditory information are integrated
134
how does the ventriloquist illusion occur
sound source being mislocalized towards a synchronous but spatially discrepant visual event. e.g. puppets mouth moving
135
spontaneous activity can lead to perceived sensation e.g.
hallucinations and tinnitus
136
maunsell and van essen
single cell recording in macaque monkeys
137
results from maunsell and van essen
neurons in area MT are selective for the direction and speed of motion
138
what was subtracted during the PET activation during visual stimulation to identify colour
activity elicited by the abstract scene shown in colour - activity elicited by abstract scene shown in greyscale
139
what was subtracted during PET activation during visual stimulation to identify motor perception
activity elicited when moving - activity elicited when stationary
140
two projection routes from primary visual cortex (V1) to extrastriate visual cortex
dorsal and ventral stream
141
stream that codes motion and location
dorsal
142
stream processes detailed stimulus features and object identity
ventral stream
143
what does each visual areas topographical represent
contralateral hemifield
144
what marks the boundaries between anatomically adjacent visual areas
topographic discontinuities
145
V4
respond to combinations of colour and form
146
what extrastriate cortex is ventral stream associated with
V4
147
V5
selective for direction and speed of motion
148
extrastriate cortex that the dorsal stream is associated with
V5
149
where are the neurons that receive information from the retinal ganglion cells located within the superior colliculi
superficial layers
150
superior colliculus experiment
monkey press bar to turn on light, monkey fixated on ligh which projected another stimulus onto the screen in order to determine receptive field of study
151
when do the monkeys receive a drop of water during the superior colliculus experiment
when they press the bar while the light was dim
152
conclusions about the superior colliculus (3)
superficial layers contain retinotopic maps of visual field
left superior colliculus represents the right hemifield
map is distorted with more neurons devoted to analysis of central portion of the visual field
153
sprague effect
visual orienting responses can be restored in the cortically blind hemifield by removing the contralesional superior colliculus
154
experiment visual cortex vs. superior colliculus damage
looks at effect of disrupting cortical vs subcortical vision using localization and discrimination tasks and making lesions of bilateral removal of visual cortex or transection of input fibres to both superior colliculi
155
localisation task
turn head toward a sunflower seed held in experimenters hand
156
discrimination task
run down a two-arm maze and enter the door behind which a sunflower seed was hidden
157
how did those with lesions in visual cortex perform
performed normal in localization task but showed impaired performance in the discrimination
158
how did those with altered superior colliculi perform
performed normal in discrimination but in localisation, made no attempt to orient towards the seed
159
when in humans can the contribution of subcortical pathways be assessed in absence of cortical pathways
after a stroke involving the primary visual cortex
160
cortical blindness
damage of V1
161
perimetry test
present a small spot of light at random locations across the visual field while patient fixates on a central stimulus
162
what happens when light falls outside the scotoma during a perimetry test
detection is immediate
163
what happens when light falls within the scotoma during a perimetry test
fail to detect the light however rods and cons are still transmitting information to the lateral geniculate nucleus
164
weiskrantz
residual vision without primary visual cortex - tone sounds, move your eyes to location of light
165
what is the dependent variable of weiskrantz test of residual vision without PVC
eye position and how far they moved after tone sounded
166
in rafal findings what was the latency with which his eyes moved towards the light that appeared in the intact hemifield?
slower when the distractor appeared in the cortically blind hemifield than when no distractor appeared, despite not being able to see
167
effect of unilateral damage to primary auditory cortex
minro due to auditory information being transmitted ipsilaterally and contralaterally.
168
movement fields -where found/what are they
neurons in deep layers of SC have movement field. movement fields are large and fire most intensely before saccades in one optimal direction
169
where are the smallest saccades represented in the SC?
in the rostral SC
170
where are the largest saccades represented in the SC
in the caudal SC
171
when do neurons in deep layer increase their discharge rate
before an eye movement
172
what proved visuomotor abilities within the SC
the fact that the cell still responded to the light on the receptive field even though no movement occurred
173
SC superficial layers
recieve info from retinal ganglion cells and contain a retinotopic map
174
SC deep layers
have either visuomotor or pure motor capabilities and contain a motor map
175
exogenous saccades =
reflexive saccades
176
what is the activity of fixation cells in the SC modulated by
an external visual stimulus at fixation
177
whats activated when a when a stimulus is present at fixation
cells in the rostral portion of the superior colliculus
178
what structure is important for the fixation reflex
SC
179
fixation offset effect paradigm
fixate on central dot, look at star in periphery when it appears
180
fixation offset condition in effect paradigm
fixation stimulus disappears when target appears
181
fixation overlap condition
fixation stimulus remains present when target appears
182
fixation offset effect paradigm independent variables
fixation overlap condition and fixation offset condition
183
what does fixation offset paradigm conclude
strong fixation reflex with a large FOE and weak for a small one
184
endogenous eye movements
voluntary eye movements
185
experiment: effects of TMS over cortex on saccadic eye movements, endogenous task
move eyes to left or right in response to a central arrowhead
186
experiment: effects of TMS over cortex on saccadic eye movements, exogenous task
move your eyes to a peripheral asterisk
187
did TMS have an effect over the superior prefrontal cortex or the superior parietal lobule of endogenous saccade task
the superior prefrontal cortex, endogenous saccades to contralateral hemifield were delayed
188
did TMS have an effect over the superior prefrontal cortex or the superior parietal lobule of endogenous saccade task
neither were affected
189
what was the theorised conclusion for disruptions of superior prefrontal cortex in endogenous movements
normal operation of the frontal eye field was disrupted
190
henik: effects of a lesion involving the frontal eye field on voluntary saccades task
move eyes to left or right in response to a central arrowhead
191
heniks conclusion
the delay in contralateral endogenous saccades associated with damage to the FEF indicate that the FEF is normally involved in generating voluntary saccades
192
reflexive eye movements are associated with which structure
the subcortical
193
voluntary eye movements are associated with which structure
the cortical
194
what is the frontal eye field important for
generating voluntary eye movements
195
anti-saccade task
fixate on centre, when stimulus appears in the periphery, move your eyes in the opposite direction then return eyes to centre
196
what does the anti-saccade task require
inhibition of a reflexive saccade, followed by execution of a voluntary saccade
197
who had most errors in anti-saccade test
children 5-8
198
machado et al: effects of a lesion involving the frontal eye field on anti-saccades supported what hypothesis
that the FEF normally imposes inhibitory control over the ipsilesional oculomotor circuitry that generates reflex saccades
199
subcortical cells in oculomotor system
mediate more primitive reflex oculomotor responses
200
phylogenetically newer cortical cells in oculomotor system
impose control over primitive reflexes via projections to subcortical cells, facilitating when advantageous and inhibiting when disadvantageous
201
what behaviour re-emerges in older adults due to ageing degenerative processes
uncontrolled reflexive behaviour due to disrupted strategic visual orienting
202
higher proportion of cortical or subcortical neurons?
humans higher cortical but frogs higher subcortical
203
overt attention
attention involved with movement of eyes
204
covert attention
attention in absence of eye movement
205
findings of the experiment looking at covert attention in occipital lobe
stronger neural signal occurred in response to the stimulus when attention was directed at the location of the stimulus
206
attention elicited by an external stimulus
exogenous shift - reflexive - superior colliculus
207
attention elicited by an internal stimulus
endogenous shift - voluntarily - cortical
208
faciliation
latency to respond to target is reduced when target appears at location of attention compared to different location.
209
what does inhibition of return provide an example of
a reflexive mechanism of attention
210
inhibition of return
when attention is directed toward a location, then there is a long delay before a target appears, latency to respond to target increases when target appears at attended location compared to different location
211
is latency decreased when target appears at same location in inhibition of return or facilitation
facilitation
212
flanker tast purpose
used to assess the efficacy of strategic control over attention (how easily distractible someone is)
213
flanker effect
reaction times on incongruent trials - reaction times on congruent trials
214
flanker task
when stimulus appears at centre indicate identity by pressing appropriate button as quickly as you can
215
3 steps of brain development
1. cell division, 2. cell migration, 3. cell differentiation
216
plasticity
refers to the neurons system ability to change. decreases with age, adults brain more rigid
217
formation of ocular dominance columns in primary visual cortex
at birth inputs from LGN of the two eyes intermingle with striate cortex V1. inputs from two eyes over development segregate into these columns.
218
ferret study: rewiring brain in newborns what is it testing
plasticity in terms of visual and auditory systems
219
ferret study: rewiring brain in newborns what was removed
the superior and inferior colliculus - so axons of retinal ganglion cells intended for SC went to MGN
220
ferret study: rewiring brain in newborns findings
by adults, neurons in auditory cortex behaved like visual neurons responding to visual stimuli
221
effects of stimulating visual cortex in adults with impaired vision
self-reported phosphenes elicited by TMS over visual cortex
222
experiment: effects of stimulating visual cortex in adults with impaired vision findings
those with some residual vision = 100%
those with poor residual vision = 60%
those with no residual vision = 20%
223
experiment = mental imagery in sighted and congenitally blind adults task
produce mental images from animal names versus passive listening to abstract words
224
what was used to measure mental imagery in sighted and congenitally blind adults and how
fMRI (brain activity during mental imagery task - brain activity during passive listening to abstract words
225
results from mental imagery experiment
production of mental images were associated with activation of visual cortex for blind people too implying they were imagining things just maybe not the same thing as we would, seeing as they would have never visually seen one
226
training and plasticity A1
training monkeys to discriminate different tone frequencies
227
what did trained frequencies lead to
enlarged cortical regions and functional plasticity within A1
228
training and plasticity M1
finger to thumb tapping sequences
229
what and how was measured in M1 for training and plasticity
fMRI used to measure activity related changes in blood flow in primary motor cortex. (left practised movements - right untrained sequential movements)
230
results for M1 training and plasticity
3 weeks + 8 weeks = greater changes in blood flow in contralateral motor cortex for trained (left) compared to untrained (right)
231
age can decline memory function which can be seen by a reduced
hippocampus
232
what can increase size of hippocampus
exercise
