Lectures Flashcards
1
Q
Types of receptors
A
1) Ionotropic
excitatory - Glutamate - AMPA + KA –> Na+
NMDA –> Na+ + Ca2+
Acetylcholine - nicotinic –> Na+
inhibitory - GABA - GABAA –> Cl-
Glycine - Glycine R –> Cl-
2) Metabotropic
excitatory - Glutamate - mGluR 1-8
Acetylcholine - muscarinic (M1- M5)
inhibitory - GABA - GABAB –> prevents Ca2+ entry
2
Q
Summation
A
1) Temporal - 1 neuron, high frequency, <15ms
2) Spatial - multiple neurons, low frequency
3
Q
Refractory period
A
1) Absolute - Na+ channels inactive –> nothing can overcome
2) Relative - K+ channels open –> very strong repolarisation needed
4
Q
Cotransmission
A
Vesicles containing a neuropeptide Y, substance P and VIP are co-released with the typical NTs for:
complex effects
longer lasting
prevents blockage of main NT by still carrying functions
5
Q
Types of fibres
A
1) Proprioception, Vibration, fine touch - heavily myelinated, fast conducting, large diameter
A alpha - proprioception from muscle spindles
A beta - touch (slightly slower)
2) Pain, Temp, crude touch - unmyelinated, slower, smaller diameter
A delta - pain and temperature
C fibres - Pain, temp, itch
6
Q
Types of neurons
A
1) Pseudounipolar - 1st order - somatosensory pathway
2) Multipolar - Reflex arc - motor neurons
3) Bipolar - Special senses
7
Q
Dorsal Column
A
Touch and proprioception
2 major tracts -
fasciculus gracilis - medial dorsal column - lower limb (after C6)
fasciculus cuneatus - lateral dorsal column - upper limb (before C6)
1) 1st order neuron ascends in dorsal column and ipsilaterally
synapses with 2nd order neuron at either nuceli gracilis or cuneatus (lower or upper limb)
2) 2nd order neuron decussate in the low medulla
3) 2nd order neuron synapses with 3rd order neuron at the thalamus and projects into somatosensory cortex (post central gyrus)
8
Q
Spinothalmic pathway
A
Pain and Temperature
2 major tracts -
Anterior - crude touch and pressure
lateral - pain and temperature
1) 1st order synapses with 2nd order neuron immediately at the dorsal root ganglion
2) 2nd order neuron ascends in either anterior or lateral fasciculi of the spinal cord an decussate 2/3 of the way there and continues to ascend on the contralateral side.
3) 2nd order neuron synapses with 3rd order neuron at the thalamus and projects into somatosensory cortex
9
Q
Posterior Dorsal Spinocerebellar Tract
A
Direct – no decussation
2 neuron pathway –> fine movement to individual muscles
1st order neuron ascends to the upper lumbar segment/ CLARKE’S COLUMN in the IPSILATERAL POSTERIOR SPINOCEREBELLAR TRACT to the cerbellum via the INFERIOR CEREBELLAR PEDUNCLE.
10
Q
Anterior Ventral Spinocerebellar Tract
A
Double cross - Ipsilateral also
2 neuron pathway –> movement of limb as a whole
1st order neuron ascends to the upper lumbar segment where they synapse with 2nd order neurons.
2nd order neurons then ascend in the CONTRALATERAL ANTERIOR SPINOCEREBELLAR TRACT to the cerbellum via the SUPERIOR CEREBELLAR PEDUNCLE where it decussates again to terminate on the Ipsilateral side.
11
Q
Acuity
A
This is the ability to discriminate between 2 points.
1) Density of receptors inc - inc acuity
2) size of receptors dec - inc acuity
3) connection with other second order neurons more connections = more signals
4) lateral inhibition - capacity of an excited neuron to inhibit the other. Axon collaterals activate inhibitory interneurons which then inhibit surrounding neurons = 1 clear signal
12
Q
Adaptation and types of receptors
A
Adaptation that is the reduction of receptor (generator) potential overtime despite continued presence of a stimulus. Hence a reduction in the frequency of AP.
1) tonic receptors - slow increase in frequency overtime –> continuous
muscle stretch
merkel’s disc
ruffini
2) phasic receptors - rapidly adapt with the fast decrease in frequency
meissner corpuscle
pacinian corpuscle
olfactory
3) phasic-tonic - rapidly decrease but has long-lasting tonic response after
13
Q
Supporting Cells of NS
A
Glial cells provide structural support and Myelin
1) astrocytes - structural support and blood brain barrier
2) oligodendrocytes - form myelin in the CNS
3) Schwann cells - form myelin in the PNS
4) ependymal cells - cells that line the ventricles and produce CSF
5) microglial - macrophages of the CNS
14
Q
Fibres within the brain
A
1) Association fibres - same hemisphere
2) commissural fibres - crosses hemisphere
3) projection fibres - cortex to sub cortical structures
15
Q
Reflex arcs
A
Three components - none involved in the Brain.
1) afferent sensory neuron - carries AP to spinal cord at the dorsal root.
2) interneuron (area of integration) - received AP from afferent neurons and elicits excitatory or inhibitory effects and activates AP in motor neurons
3) Motor neuron - leaves from ventral horn to effector organ skeletal muscle (somatic) or smooth/cardiac (ANS)
16
Q
what brain area is rich in enkephalin synapses
A
periaqueductal grey
17
Q
Why does some motion eg spinning lead to dizziness?
A
movement of the otoliths (crystals) to the semi-circular canal
18
Q
Function of palatine tonsil
A
produces lymph which drains into the jugulodigastric group of lymph nodes
19
Q
what part of the neuron does the following
- receives signal
- transmits signal
A
- dendrite
2. axon
20
Q
what is stimulus duration based on?
A
duration of AP
21
Q
is the stimulus duration based on the continual presence of stimulus
A
NO
22
Q
what structure does a reflex integrate with directly?
A
Spine
**NOT the brain
23
Q
Give an example of a monosynaptic reflex
A
stretch reflex
24
Q
describe the structure of B type fibres
A
myelinated, small diameter fibres of ANS
25
where is melatonin produced
pineal gland
26
function of melatonin
induces sleep
27
what hormone is secreted during NREM or slow wave sleep
Growth hormone
28
what ion contributes to excitotoxicity within neuronal cells?
Calcium
29
Sweat glands are stimulated by the _________ NS.
Cholinergic Sympathetic
30
What produces CSF? What percentage does it produce?
choroid plexus (70%), other brain capillaries
31
Absorption in the subarachnoid space is done by ________.
Bulk transport
32
What is the value of normal ICP?
10mmHg
33
An increase in _______ leads to an increase in ICP.
volume
34
What does the 1A sensory afferents synapse on?
alpha motor neuron
| **NO INTERNEURON
35
What do muscle spindles regulate?
length/rate of change of length
36
What does golgi tendon organs regulate?
tension/rate of change of tension
37
What is the relationship of length and tension of muscles?
they are inversely proportional
38
Where are the muscle spindles found?
They are found in the extrafusal fibres which wraps around the intrafusal fibres.
39
How is muscle length and tension balanced?
Muscle spindles --> 1A --> CNS --> alpha motor neurons --> extrafusal fibres --> length
Golgi tendon --> 1B --> CNS --> gamma motor neurons --> intrafusal fibres --> tension
40
What is the relationship between firing of sensory receptors and 1) stretch, 2) tone?
as firing increases, stretch increases, tone decreases
41
What happens to the length and tone of the muscle after the initial stretch.
stretch --> muscle contracts --> length dec, tone inc
42
What regulates tone?
stretch reflex
| **tone is not a characteristic of the muscle itself
43
Describe the mechanism by which golgi tendon organ works.
detects tension
| inhibits alpha motor neuron
44
Describe the sequence of occurrences of the knee jerk.
tapping patellar ligament --> brief stretch of the muscle --> stretch of muscle spindles --> firing of 1A sensory afferent fibres increases --> alpha motor neuron activity in quads increases --> contraction of quads --> knee extends and leg kicks forward.
45
What are polysynaptic reflexes?
These reflexes involve 1 or more interneurons.
46
When does reciprocal innervation occur? Explain the mechanism.
When a muscle (protagonist) contracts, interneurons release inhibitory NTs (such as GABA, Glycine) causing the antagonist muscle to relax.
47
What is the antagonist of the knee-jerk reflex?
semitendinosus
48
Explain the withdrawal reflex.
it is a polysnaptic reflex.
sensory neurons --> interneuron --> stimulates biceps (flexor) to contract ; inhibits contraction of the extensor triceps (antagonist)
49
Explain the responses of the flexors and extensors during the crossed extensor reflex.
+ flexor 1, - extensor 1
- flexor 2, + extensor 2
**spinal reflexes are not limited to one side of the body such as the crossed reflex
50
What are the classifications of pain and nociceptors? Are they adaptive or maladaptive?
Actue - adaptive
Subacute - adaptive
Chronic - maladaptive
51
Describe the characteristics of acute pain.
transient
few seconds
associated with detection of potentially tissue damaging stimuli.
52
Describe the characteristics of subacute pain.
associated with tissue damage and immune cell infiltration
53
Describe the characteristics of chronic pain.
exceeds possibility to resolve damage
| may become pathological
54
What does it mean if a pain is said to be adaptive?
there is a protective mechanism present to prevent further damage
55
What are nociceptors?
pain receptors that respond to a mechanical or chemical stimuli or both.
56
What is the term given to describe a nociceptor that responds to both types of stimuli?
polymodal
57
what type of fibres are involved in the pain pathway?
Adelta and C
58
Describe the pain associated with A delta fibres.
highly localised first pain
| afferent pathway for reflex - low threshold
59
Describe the pain associated with C fibres.
polymodal, poorly localised, second pain, much slower
| high threshold
60
Where does the somatic pain pathway pass?
goes along lateral spinothalmic tract (corticospinal)
61
What does the salience model of drug taking imply?
Users want the drug more when reward the cues are present
62
The opening of a what channel is common to both graded potentials and action potentials?
Sodium channels
63
What nociceptive stimuli is released by the immune system?
Inflammatory chemicals such as histamine
64
Falx cerebri
separates hemispheres of the cerebrum
65
separates hemispheres of the cerebrum
Falx cerebri
66
tentorium cerebeli
separates cerebrum and cerebellum
67
separates cerebrum and cerebellum
tentorium cerebeli
68
what produces aqueous humour?
cilliary between cornea and lens of eye and retinal cells in the vitreous part of the eye.
69
What cells have the longest source of electrical signals of output to the optic nerve?
ganglion cells
70
What cells contribute to visual signal transduction?
horizontal
| amacrine
71
What nucleus regulates the circadian rhythm? where is it located?
Suprachiasmatic nucleus in hypothalamus
72
What is the significance of a vitamin A deficiency?
nightblindness
| inability ot regenerate rhodopsin
73
What vitamin is important in the regeneration of rhodopsin?
Vitamin A
74
What characteristic of light do neurons in the visual cortex respond to?
orientation
75
what structure within the eye is over-represented in visual processing?
fovea
76
What part of the brain re-inverts an image?
cortex
77
what is the sensory component of the occulomotor nerve?
optic nerve
78
eustation tube function
connects nasal cavity to middle ear
| equalizes pressure and drains fluid from the throat
79
what is the result of a positive rinne/ weber test?
BC
80
what part of the inner ear controls balance?
vestibular
81
what part of the inner ear controls hearing?
cochlear
82
What comprises the continuous fluid system in the ear?
scala vestibuli
| scala tympani
83
separation of scala vestibuli and scala tympani
helico trema directly
| scala media indirectly
84
tectorial membrane
in the organ of corti
stiff membrane
involved in mechanotransduction of sound by shearing of cilia of hair cells
85
Damage to what structure within the ear causes a cochlear implant to not work?
cochlear nerve fibres
86
hair cells in cochlear apparatus
cilia
87
hair cells in vestibular apparatus
stereocilia
88
where is perilymph found
scala vestibuli
| scala tympani
89
where is endolymph found
scala media
| semicircular canals
90
rate of use of heat from metabolic oxidation of food
80kcal/hr
91
thermoneutral zone
range range where temperature control is maintained by vasomotor responses only
92
vasomotor responses
constriction and dilation of peripheral vessels
93
cranial nerve pain pathway
- 1st order neuron travels via trigeminal nerve to brainstem
- synapses with 2nd order neuron
- decussates and ascends into thalamus
- synapse with 3rd order neuron
- to cortex
94
ascending nociceptive pathway
excitatory
glutamate - AMPA, NMDA, KA
Substance P - Neurokinin 1
95
Descending nociceptive pathway
inhibitory
GABA - GABAa, GABAb
opioids - afferent pain fibres (3 receptors)
endocannabinoids
96
What substance allows for the transmission of signals from periphery to brain?
substance P
97
action of opiates
inhibit NT release from 1st order neurons and hyperpolarise the 2nd order neurons
98
types of endogenous opioid receptors
Mu and beta endorphins -- increases K+ conductance on postsynaptic neuron
delta and enkephalins
kappa and dynorphins
99
action of endogenous opioid receptors
inhibits substance P and glutamate release by stopping ca2+ release and inhibit their effects on postsynaptic neurons, hyperpolarising them
Mu and beta endorphins -- increases K+ conductance on postsynaptic neuron
100
where are endogenous opioid receptors found?
pre-synaptic except Mu
101
action of endocannabinoids
GABA released - binds to GABA receptor on post-synaptic neuron
releases 2-AG and Anandamides into synaptic cleft
bind to GPCR cannabinoid receptors (CB1, CB2)
analgesic effects
102
inhibition of adenylyl cyclase leads to ....
decrease cAMP
blocks Ca2+ channels
increase K+ channels
103
k+ is mediated by what endogenous opioid receptor
Mu
104
Gate theory
lg diameter fibres (Aalpha and Abeta) synapse with interneurons
block transmission of c fibres
105
what is the 'gate' in gate theory
interneurons
106
when is the gate open
no stimuli
107
the large fibre _____ the gate
the small _______ it
no fibre _____ it
closes
opens
closes
108
Allodynia
feeling of pain when not normally stimulated
109
hyperalgesia
enhanced sensation of pain at normal threshold
110
enhanced states of pain
protective measures of sensitisation
111
protective measures of sensitisation
| types
enhanced states of pain
peripheral
central
112
peripheral sensitisation
release of substance p --> increase in sensitivity in surrounding cells
113
release of substance p --> increase in sensitivity in surrounding cells
peripheral sensitisation
114
central sensitisation
increase NMDA receptors on dendrites of second order neurons
115
increased NMDA receptors on dendrites of second order neurons
central sensitisation
116
pathological pain
chronic pain
117
neuropathic pain
neural lesions
118
symptoms of neural lesions
positive - increased chronic pain
| negative - sensory loss/ numbness
119
dysfunctional pain
non-neural lesion
120
symptoms of non-neural lesion
positive - increased chronic pain
121
types of neuropathic pain
```
central:
strokes
cord injury
MS
PD
```
peripheral:
Nerve fibres
diabetic neuropathy
122
diabetic neuropathy
peripheral neuropathic pain
123
strokes
central neuropathic pain
124
corticobulbar pathway
conveys info from cortex to cranial nerve motor nucleus
| UMN axons --> genu --> decussate just before synapsing with LMN
125
cell body of UMN
pre central gyrus
126
cell body of LMN in corticobulbar pathway
motor nucleus of trigeminal nerve
127
corticospinal pathway
conveys info from cortex to ventral horn cells of spinal cord
UMN axons --> posterior limb --> through midbrain, pons, pyramids
85% decussates at pyramids --> lateral corticospinal tract --> descends spinal cord and synapses with LMN
15% does not decussate --> anterior corticospinal tract --> descend and decussate near termination (LMN)
128
cell body of LMN in corticospinal pathway
ventral horn
129
decussation in lateral corticospinal tract
85%
| at pyramids
130
decussation in anterior corticospinal tract
15%
| near termination
131
What pathway passes through the genu?
corticobulbar pathway
132
What pathway passes through the posterior limb of the internal capsule?
corticospinal pathway
133
decussation in corticospinal pathway
just before synapsing with LMN
134
Extrapyramidal pathways
rubrospinal
tectospinal
vestibulospinal
135
rubrospinal pathway
cerebellum --> cortex
| tone of flexor muscles of limbs
136
tectospinal pathway
superior colliculi
| reflex movement to audio and visual stimuli
137
vestibulospinal pathway
vestibular nuclei in pons and medulla
| tone of extensor muscles
138
tectum
posterior to aqueduct in midbrain
| superior and inferior colliculi
139
superior colliculi
visual reflex
140
inferior colliculi
auditory reflex
141
tegmentum
all of brainstem anterior to aqueduct
| homeostatic and reflexive pathways
142
consciousness
state of self awareness
| ability to respond to stimuli
143
sleep
changed consciousness, can be aroused by stimulation
144
coma
profound unconsciousness
inability to respond and sense external stimuli
loss of the sleep-wake cycle
145
vegetative state
unconsciousness
when coma progresses
sleep-wake cycle
no response to external stimuli other than pain
146
brain dead
lack of brain activity and cranial nerve reflexes
147
state of self awareness
| ability to respond to stimuli
consciousness
148
changed consciousness, can be aroused by stimulation
sleep
149
profound unconsciousness
inability to respond and sense external stimuli
loss of the sleep-wake cycle
coma
150
unconsciousness
when coma progresses
sleep-wake cycle
no response to external stimuli other than pain
vegetative state
151
lack of brain activity and cranial nerve reflexes
brain dead
152
stages of sleep
```
awake with eyes open
awake with eyes closed
NREM 1
NREM 2
NREM 3
NREM 4
REM
```
153
rhythm when awake with eyes open
beta
154
rhythm when awake with eyes closed
alpha
155
NREM 1
light sleep
slow eye movement
theta waves of high amplitude and low frequency
156
NREM 2
```
no eye movement
slow brain waves
bursts of rapid waves
low frequency
k complexes
spindles
```
157
NREM 3
extremely slow
| delta waves interrupted by small and faster waves
158
NREM 4
exclusively delta waves
159
REM
EEG - fast and low amplitude
EOG - very rapid eye movements
EMG - flaccid/ hypotonic (little to no wave)
160
light sleep
slow eye movement
theta waves of high amplitude and low frequency
NREM 1
161
```
no eye movement
slow brain waves
bursts of rapid waves
low frequency
k complexes
spindles
```
NREM 2
162
extremely slow eye movement
| delta waves interrupted by small and faster waves
NREM 3
163
exclusively delta waves
NREM 4
164
EEG - fast and low amplitude
EOG - very rapid eye movements
EMG - flaccid/ hypotonic (little to no wave)
REM
165
theta waves
NREM 1
166
k complexes
| spindles
NREM 2
167
delta waves interrupted by small and faster waves
NREM 3
168
exclusively delta waves
NREM 4
169
slow eye movement
NREM 1
170
no eye movement
NREM 2
171
extremely slow eye movement
NREM 3
172
no response to external stimuli other than pain
vegetative state
173
inability to respond and sense external stimuli
coma
174
brain wave of: NREM 1
theta waves
175
brain wave of: NREM 2
k complexes
| spindles
176
brain wave of: NREM 3
delta waves interrupted by small and faster waves
177
brain wave of: NREM 4
exclusively delta waves
178
brain wave of: REM
EEG - fast and low amplitude
EOG - very rapid eye movements
EMG - flaccid/ hypotonic (little to no wave)
179
How long does it take to complete 1 alternating cycle of the sleep cycle?
90 minutes
180
As sleep progresses, NREM sleep becomes ___A____ while REM sleep becomes ___B___.
A - less deep
| B - longer
181
In what order does the stages of NREM disappear?
1 and 4
| 3
182
How many alternating cycles are typically undergone in one night?
5-6
183
what trend is observed in the sleeping patterns of infants
many short naps which eventually increase in length and decrease in number
184
what trend is observed in the sleeping patterns of adults
duration of sleep and length of REM becomes shorter
185
What age group is known to have many short naps which eventually increase in length and decrease in number
infants
186
What controls the sleep cycle?
RAS reticular formation
| SCN (suprachiasmatic)
187
RAS reticular formation
controls sleep cycle
involves cholinergic neurons (Ach) and monoaminergic (monoamines)
During NREM both pathways slow down
During REM cholinergic neurons fire, monoaminergic stops
188
The pathways in the RAS reticular formation involve what type of neurons?
cholinergic neurons (Ach) and monoaminergic (monoamines)
189
What events occur during NREM of RAS reticular formation?
both pathways slow down
190
What events occur during REM of RAS reticular formation?
cholinergic neurons fire, monoaminergic stops
191
The response below is generated by the RAS reticular formation. Identify what stage of sleep has this response.
cholinergic neurons fire, monoaminergic stops
REM
192
The response below is generated by the RAS reticular formation. Identify what stage of sleep has this response.
both pathways slow down
NREM
193
SCN (suprachiasmatic)
controls sleep cycle
| input from retina links light to day-night cycle
194
What gland makes melatonin?
pineal gland
195
function of melatonin
induce sleep
196
In a standard sleep schedule, at what point is the sleep schedule is growth hormone release?
NREM/ slow wave sleep
| 10pm - 2am
197
Where is CSF made?
tufts of capillaries that invaginate ventricles called the choroid plexus
198
What part of the brain is CSF transported to after production?
subarachnoid space (cisterns)
199
what mechanisms are used to transport CSF to the subarachnoid space?
passive and active transport
200
function of CSF
supports and protects the brain
201
structure of choroid plexus
2 cell thick layer
| endothelial cells of capillary and ependymal cells (tight junction)
202
describe the movement of hydrophilic molecules across the blood CSF barrier.
do not freely move
| rely on transport proteins (glucose - GLUT1)
203
describe the movement of hydrophobic molecules across the blood CSF barrier.
freely moves across both layers
204
What type of molecules do not freely move through the blood CSF barrier and rely on transport proteins.
hydrophilic molecules
205
What type of molecules freely moves across both layers of the blood CSF barrier.
hydrophobic molecules
206
compare the composition of blood and CSF
```
CSF has:
more Na+Cl-
less glucose
little to no proteins
less K+
```
207
Between blood and CSF which has:
| more Na+Cl-
CSF
208
Between blood and CSF which has:
| less glucose
CSF
209
Between blood and CSF which has:
| little to no proteins
CSF
210
Between blood and CSF which has:
| less K+
CSF
211
Between blood and CSF which has:
| less Na+Cl-
Blood
212
Between blood and CSF which has:
| more glucose
blood
213
Between blood and CSF which has:
| more K+
blood
214
What forms the blood-CSF barrier?
choroid plexus
capillaries
transporters
215
Compare the BBB and the CSF-blood barrier.
functionally the same]
structurally different - BBB is only one cell think composed of flattened endothelial cells of capillaries connected by tight junctions and astrocytes.
216
describe the structure of the BBB
only one cell think composed of flattened endothelial cells of capillaries connected by tight junctions and astrocytes.
217
What type of cells are found in the CSF-blood barrier but not the BBB?
ependymal cells
218
One structural similarity of the CSF-blood barrier and the BBB
presence of tight junctions
219
What type of cell is found in the BBB but not in the CSF-blood carrier?
astrocytes
220
What is the function of astrocytes in the BBB?
give structural support
221
function of the BBB
maintains constant environment for neurons in CNS
222
Clinical significance of BBB when taking medications.
avoids CNS side effects as the drug must be able to cross the BBB
223
How do the presence of tumours disrupt the functioning of the BBB when taking medications?
They have no barriers and hence allows for the free entry of substances
224
Is the cranium compressible?
NOPE
225
How does a rise in ICP affect blood vessels?
compresses them
226
How does a rise in ICP affect cerebral blood flow?
decreases --> ischemia
227
What is cushing's reflex?
a pathophysiological reflex triggered when there is a severe decreases in cerebral perfusion.
228
describe cushing's reflex.
a pathophysiological reflex triggered when there is a severe decreases in cerebral perfusion. --> hypercapnia and hypoxia --> activates medullary vasomotor centre --> increases peripheral vasoconstriction --> blood redirected to brain --> increase in arterial Bp (increase in firing of baroreceptors) --> reflex bradycardia (cardio inhibitory centre)
229
end result of cushing's reflex.
reflex bradycardia
230
there is an increase in firing of what type of receptors as arterial Bp incresases?
baroreceptors
231
what does a decrease in cerebral perfusion lead to in cushing's reflex?
hypercapnia and hypoxia
232
hypercapnia and hypoxia activates what centre of the brain?
medullary vasomotor centre
233
what does the activation of the medullary vasomotor centre result in?
increases peripheral vasoconstriction
234
what there is an increase in peripheral vasoconstriction, what happen to the blood during cushing's reflex?
redirected to brain
235
the blood redirected to brain in cushing's reflex results in what?
increase in arterial Bp
236
"brain's shortcut for emotion" pathways
slow - proper interpretation
| fast - thalamus --> amygdala - autonomic arousal and hormonal responses
237
what emotional pathway allows for proper interpretation
slow
238
what emotional pathway allows for autonomic arousal and hormonal responses
fast
239
what structures are involved un the fast emotional pathway?
thalamus --> amygdala
240
what are the functions of the hypothalamus
```
modulation of ANS activity
modulates the circadian rhythm
controls homeostasis
controls emotional behaviour
*hunger centre
```
241
where is the hunger centre of the brain located?
lateral hypothalamus
242
what does a damage in the hunger centre lead to?
lack of appetite
243
what results from a lesion of the anterior hypothalamus
disruption in circadian rhythm
244
hippocampal formation
structures involved in learning, memory and recognition of novelty
245
amygdaloid complex
modulates endocrine activity, sexuality, reproduction, autonomic responses and emotion.
facilitates perceptual and memory functions in those regions
246
what part of the brain is involved in learning, memory and recognition of novelty
hippocampal formation
247
what part of the brain modulates endocrine activity, sexuality, reproduction, autonomic responses and emotion.
amygdaloid complex
248
what part of the brain facilitates perceptual and memory functions in those regions
amygdaloid complex
249
What key structures regulate emotions
orbital prefrontal cortex and ventromedial prefrontal cortex
dorsolateral prefrontal cortex
amygdala
anterior cingulate cortex
250
what parts of the PFC are involved in regulation of emotional responses?
orbital prefrontal cortex and ventromedial prefrontal cortex
| dorsolateral prefrontal cortex
251
function of PFC
tasks that need attention
inhibitory control
decision making
252
what is the result of the destruction in any key emotional regulatory structure?
increase propensity for impulsive aggression and violence
253
Kluver-Bucy Syndrome
after bilateral destruction of the anterior temporal lobes, including the amygdaloid complex
symptoms: triad of docility (absence of fear), hyperorality and hyper-sexuality
254
the triad of docility (absence of fear), hyperorality and hyper-sexuality is associated with what illness?
Kluver-Bucy Syndrome
255
what is the name given the illness cause by the bilateral destruction of the anterior temporal lobes, including the amygdaloid complex
Kluver-Bucy Syndrome
256
is the amygdaloid complex destroyed in Kluver-Bucy Syndrome?
YUP
257
damage to amygdala
decrease conditioned fear response
| decreased ability to recognise meaningful facial and vocal expressions of anger in others
258
damage to hippocampus
inability to make and store long term memories
259
death of neuronal hippocampal cells are present in what illness?
Alzheimers
260
What physical changes do the hippocampus and amygdala undergo in schizophrenia
decrease in size
261
A decrease conditioned fear response is a typical symptom of damage to what structure of the brain?
amygdala
262
A decreased ability to recognise meaningful facial and vocal expressions of anger in others is a typical symptom of damage to what structure of the brain?
amygdala
263
The inability to make and store long term memories is a typical symptom of damage to what structure of the brain?
hippocampus
264
What happen to the cells of the hippocampus in an illness such as Alzheimers?
death of neuronal hippocampal cells
265
The hippocampus and amygdala decrease in size in what illness?
schizophrenia
| depressive disorder
266
what does anxiety result from?
hyper-activation of the amygdala
267
in severe anxiety disorders, what structures are not functioning normally? what happens?
decreased threshold for amygdala to detect potential threats
decrease in ventrolateral prefrontal cortex activation (severe)
268
What physical changes occur to structures in the brain in depressive disorders?
decrease size of amygdala
| decrease size of PFC specifically the orbitofrontal cortex
269
in depressive disorders, what structures are not functioning normally? what happens?
increased amygdala activation in response to fear and sad faces
increased activity of PFC (ventral)
270
How do antidepressants work?
they decrease the hyperactivation of the amygdala and the ventral PFC
271
what is the maslow heirachy of motivation
from bottom --> top
physiological (water and food)
safety (security and protection)
love/belongingness (closeness and affiliation)
esteem (self and others)
self-actualisation (express oneself; growth; actualise potential of one's self)
272
place the following elements of the maslow heirachy of motivation in order (bottom to top)
esteem (self and others)
love/belongingness (closeness and affiliation)
physiological (water and food)
self-actualisation (express oneself; growth; actualise potential of one's self)
physiological (water and food)
from bottom --> top
physiological (water and food)
safety (security and protection)
love/belongingness (closeness and affiliation)
esteem (self and others)
self-actualisation (express oneself; growth; actualise potential of one's self)
273
Motivation disorders can be broadly categorised into __A__ categories. what are these categories. give an example of each.
A - 2
1) apathy and physiological defects (eg. schizophrenia and mood disorders)
2) addictions (misdirection of motivation) - Eg frug addiction
274
schizophrenia and mood disorders falls into what category of motivation disorder?
apathy and physiological defects
275
what is the basic mechanism of integration of motivation in the brain
the brain weighs the cost:benefit ratio depending on: physiological state
environment
past history
276
How does the brain interpret repeat experiences?
repeat experiences make pathways that links the experience to specific thoughts, memories and behaviours.
277
How does an increase in dopamine affects behavioural patterns?
reinforces the behaviour
278
Anterior cingulate cortex (ACC)
regulates one's own behaviour and monitors the behaviour of others
determines when behaviour needs to be modified
279
what part of the brain makes dopaminergic neurons?
pars compacta of the substantia nigra
280
what does the pars compacta produce?
dopaminergic neurons
281
Nucleus Accumbens
evaluates stimuli that produces a wanting or liking response (usually those that release dopamine)
learning from feedback and in reward based decision-making.
282
substantia nigra and the ventral tegmental areas
produces dopamine
| delivers it to other regions that are involved in motor function and in motivating and rewarding behaviours
283
raphe nuclei
seretonin production
| deliver to network circuits in the brain including structures related to motivation, reward and threat detection
284
what structure produces serotonin?
raphe nuclei
285
what structure delivers dopamine to other regions that are involved in motor function and in motivating and rewarding behaviours
substantia nigra and the ventral tegmental areas
286
where is dopamine delivered to?
other regions that are involved in motor function and in motivating and rewarding behaviours
287
where is seretonin delivered to?
to network circuits in the brain including structures related to motivation, reward and threat detection
288
Serotonin pathways
key factor in 'liking'
combines with other neurochemical to convey euphoria
widest distribution in the brain
major influence on emotional states, sleep cycles, eating and other rewarding behaviours
289
What substance conveys euphoria?
Serotonin
290
What substance has the widest distribution in the brain?
Serotonin
291
What substance has a major influence on emotional states, sleep cycles, eating and other rewarding behaviours
Serotonin
292
what does Serotonin influence?
emotional states, sleep cycles, eating and other rewarding behaviours
293
What psychiatric diagnoses involves a dysregulation of serotonin?
depression
294
What psychiatric diagnoses are involved with motivational deficits?
```
depression
schizophrenia
bipolar disorder
PTSD
anxiety disorders
```
295
How do motivational deficits affect normal functioning?
interfere with cognitive abilities
impede functional outcomes
impair subjective wellbeing
296
1 Main negative symptom of schizophrenia?
avolition - decrease in motivated self-initated purposeful activities
297
1 criteria of manic/ hypomanic episodes
increase in goal-directed activity
298
Aberration in reward processing can lead to ...
addiction
299
What is used in the treatment of addictions?
extrinsic motivators to change behaviour
300
cognitive/ behavioural approaches
creating reward contingencies that modify deficits or excesses in behaviour
301
what is deep brain stimulation used for?
```
essential tremour
parkinson's disease
treatment refractory major depression
OCD
Chronic pain
```
302
what are the major functions of the frontal lobe?
```
(motor)
movement
executive control
planning
language
personality
```
303
which part of the brain controls movement
frontal lobe
304
which part of the brain controls executive control
frontal lobe
305
which part of the brain controls planning
frontal lobe
306
which part of the brain controls language
frontal lobe
307
which part of the brain controls personality
frontal lobe
308
what are the functional parts of the frontal cortex? how many parts are there?
3 part
primary motor - gross and fine movement
premotor cortex - planning and selective movement
prefrontal cortex - integrates multimodal sensory information (post gyrus)
309
what is the function of the primary motor?
gross and fine movement
310
what is the function of the premotor cortex?
planning and selective movement
311
what is the function of the prefrontal cortex?
integrates multimodal sensory information (post gyrus)
312
what part of the brain controls gross and fine movement
frontal lobe - primary motor
313
what part of the brain controls planning and selective movement
frontal lobe - premotor cortex
314
what part of the brain integrates multimodal sensory information (post gyrus)
frontal lobe - prefrontal cortex
315
frontal lobe damage
problems in intellectual abstraction and concentration
problems with executive function, sequencing and speed
personality changes - instability, social difficulties, says what they think (disinhibition)
Broca's Aphasia - difficulty producing speech, disjointed words, comprehension preserved, aware of problem
inability to find and create patterns or to change action when rules have changed.
316
what causes problems in intellectual abstraction and concentration?
frontal lobe damage
317
what causes problems with executive function, sequencing and speed
frontal lobe damage
318
what causes personality changes - instability, social difficulties, says what they think (disinhibition)
frontal lobe damage
319
what causes Broca's Aphasia
frontal lobe damage
320
what causes inability to find and create patterns or to change action when rules have changed.
frontal lobe damage
321
what causes difficulty producing speech, disjointed words, comprehension preserved, aware of problem
frontal lobe damage - Broca's Aphasia
322
what is Broca's Aphasia
difficulty producing speech, disjointed words, comprehension preserved, aware of problem by frontal lobe damage to Broca's area
323
what lobe controls motor function?
frontal
324
what lobe controls senses and perception?
parietal
325
what is the function of the parietal lobe?
```
somatosensory with info from visual system
perception of language
attention
learning
coordination in space
```
326
what lobe is responsible for perception of language
parietal lobe
327
what lobe is responsible attention
parietal lobe
328
what lobe is responsible learning
parietal lobe
329
what lobe is responsible learning coordination in space
parietal lobe
330
what is the importance of the functional parts of the parietal lobe?
primary somatosensory cortex - receives and interprets sensory information (contralateral)
somatosensory unimodal association area - further processes sensory information
multimodal sensory association area - interprets afferents from somatosensory, visual, auditory and movement in 3D space
331
what part of the brain interprets movement in 3D space
multimodal sensory association area or parietal lobe
332
what results from parietal lobe damage
denial/ neglect of 1/2 of the visual field (contralateral)
apraxia - inability to carry out movement
agnosias - inability to recognise words, numbers and location
difficulty integrating information from various parts of the body
difficulty with skills requiring knowledge of relations (eg numbers)
difficulty with skills requiring manipulation of objects
333
how is agnosias tested?
maze
334
what is apraxia?
inability to carry out movement
335
what is the name of the illness characterised by the inability to carry out movement?
apraxia
336
what is agnosias?
inability to recognise words, numbers and location
337
what is the name of the illness characterized by the inability to recognise words, numbers and location?
agnosias
338
what causes denial/ neglect of 1/2 of the visual field (contralateral)
parietal lobe damage
339
what causes apraxia
parietal lobe damage
340
what causes inability to carry out movement
parietal lobe damage
341
what causes agnosias
parietal lobe damage
342
what causes inability to recognise words, numbers and location
parietal lobe damage
343
what causes difficulty integrating information from various parts of the body
parietal lobe damage
344
what causes difficulty with skills requiring knowledge of relations (eg numbers)
parietal lobe damage
345
what causes difficulty with skills requiring manipulation of objects
parietal lobe damage
346
what is lobe of the brain is involved in vision?
occipital
347
what is the importance of the functional parts of the occipital lobe?
Primary visual cortex - initial processing of visual information from thalamus
Visual unimodal Association area - further Processing of the visual information from primary visual cortex
348
where does visual information go after being processed by the occipital lobe?
Multimodal sensory Association areas of the parietal and temporal lobe
349
Where are the multimodal sensory Association areas located in the brain?
Parietal and temporal lobe
350
Visual information from the occipital lobe goes to which lobes?
Parietal and temporal lobe
351
What results from occipital lobe damage?
Cortical blindness - lesion in primary visual cortex, normal eye, visual stimuli received but cannot be interpreted - confabulates the response
Inability to recognise what is seen, cannot draw what is in front of them.
352
what causes Cortical blindness
occipital lobe damage
353
what causes lesion in primary visual cortex, normal eye, visual stimuli received but cannot be interpreted -confabulates the response
occipital lobe damage
354
what causes Inability to recognise what is seen, cannot draw what is in front of them.
occipital lobe damage
355
what is cortical blindness?
lesion in primary visual cortex, normal eye, visual stimuli received but cannot be interpreted - confabulates the response
356
what is the function temporal lobe?
```
auditory
memory
language comprehension
taste
smell
facial recognition
```
357
what part of the brain is responsible for language comprehension
temporal lobe
358
what part of the brain is responsible for facial recognition
temporal lobe
359
what part of the brain is responsible for taste
temporal lobe
360
what part of the brain is responsible for smell
temporal lobe
361
what are the functional regions if the temporal lobe?
primary auditory cortex
auditory unimodal association areas
visual unimodal association (also in occipital)
multimodal sensory association areas
limbic association areas - memory, learning, feelings, emotions associated with senses (visual and auditory stimuli)
amygdala and hippocampus - components of limbic system
362
what results from temporal lobe damage?
Wernicke's aphasia - loss of comprehension, silent reading, speaks fluently with no meaning
memory difficulties - left damage - impaired verbal memory, right damage - impaired non-verbal memory (music)
difficulty recognizing faces
inability to characterize objects
363
what causes Wernicke's aphasia
temporal lobe damage
364
what causes loss of comprehension, silent reading, speaks fluently with no meaning
temporal lobe damage - Wernicke's aphasia
365
what causes memory difficulties
temporal lobe damage
366
what causes impaired verbal memory
temporal lobe damage left damage to memory
367
what causes impaired non-verbal memory (music)
temporal lobe damage - right damage to memory
368
what causes difficulty recognizing faces
temporal lobe damage
369
what causes inability to characterize objects
temporal lobe damage
370
what is Wernicke's aphasia
loss of comprehension, silent reading, speaks fluently with no meaning
371
what illness is characterised by loss of comprehension, silent reading, speaks fluently with no meaning
Wernicke's aphasia
372
is a person with Wernicke's aphasia aware of their problem?
NOPE
373
What do the characteristics of light govern?
wavelength - colour (ROYGBIV) (780-550-400)
| amplitude - brightness
374
what is the wavelength of red light?
780
375
what is the wavelength of violet light?
400
376
what is the wavelength of green light?
550
377
what is the relationship of wavelength, frequency and energy?
wavelength is inversely proportional to frequency and energy
378
significance of choroid
nutritional
| pigments
379
significance of retina
photoreceptors and neurons
380
significance of cornea
2/3 of the light converges
381
what produces aqueous humour
ciliary
382
significance of iris
adjusts pupil diameter by the contraction of radial and circular muscles
383
what is responsible for the adjustment of pupil size
radial and circular muscles
| ie dilator and sphincter pupillae
384
significance of lens
adjusts focal length
385
how does the lens adjust focal length
by changing the curvature by the suspensory ligaments and the ciliary apparatus
386
significance of macula
region containing fovea
387
significance of fovea
only cones
| most photoreceptors at this point
388
what structure of the eye converges light?
cornea (2/3)
| lens (1/3)
389
what alters the shape of the lens?
ciliary muscles of the PNS (III)
390
what is the shape of the lens?
biconcave
391
explain the alteration of the shape of the lens in viewing a distant image?
distant vision --> relax --> flatten lens --> increase in focal length --> no stimulation
392
explain the alteration of the shape of the lens in viewing a near image?
near vision --> contracts --> more convex --> decrease in focal length --> PNS stimulation
393
stimulation of the PNS is involved in ______ vision.
near
394
the lens flattens when viewing a ____ object.
distant
395
the lens takes on a more convex shape when viewing a ______ object.
nearby
396
the ciliary muscles ____ in distant vision
relaxes
397
the ciliary muscles ____ in near vision
contracts
398
the focal length _____ in distant vision
increases
399
the focal length _____ in near vision
decreases
400
is the pupil a hole?
YES
401
what induces a change in pupil diameter?
change in light intensity
402
how does a change in light intensity affect the pupil?
change is diameter
403
explain the alteration of pupil diameter in response to light intensity.
PNS --> pupil constriction --> circular muscle (sphincter pupillae) --> reduces light --> increase DoF (depth of focus) and decrease FoV (field of view)
SNS --> pupil dilation --> radial muscles (dilator pupillae) --> increases light --> decrease DoF and increase FoV
404
what NS is responsible for pupil constriction
PNS
405
what NS is responsible for pupil dilation?
SNS
406
what changes in DoF and FoV result from the pupil constriction?
increase DoF (depth of focus) and decrease FoV (field of view)
407
what changes in DoF and FoV result from the pupil constriction?
decrease DoF and increase FoV
408
what is the retina
it is the part of the eye where the image is focused on and is comprised of 3 layers
409
how many layers does the retina had?
3
410
what are the layers of the retina
photoreceptors - rods and cones (graded potential to bipolar cells)
bipolar cells - receives graded potential from photoreceptors and releases NTs from ganglion cells
ganglion cells - axons of which form the optic nerve and send out action potential
411
photoreceptors
rods and cones (graded potential to bipolar cells)
412
bipolar cells
receives graded potential from photoreceptors and releases NTs from ganglion cells
413
ganglion cells
axons of which form the optic nerve and send out action potential
414
the axons of which cell type directly contact the optic nerve?
ganglion cells
415
where are NTs in the eye released from?
ganglion cells
416
what cell causes the release of NTs
bipolar cells
417
what cells in the eye generate a graded potential?
photoreceptors
418
what cells in the eye generate an action potential
ganglion cells
419
parts of retina
neural - deals with perception and transduction of light into electrical signals
pigmented - lines retina
420
function of neural part of retina
deals with perception and transduction of light into electrical signals
421
what part of the retina deals with perception and transduction of light into electrical signals
neural part
422
what is the thinnest part of the retina
fovea
423
what is the center if the retina
fovea
424
what part of the retina has the highest density of photoreceptors?
fovea
425
what part of the retina has only cones?
fovea
426
what part of the retina has no blood vessels
fovea
427
what part of the retina has no photorecptors?
optic disc
428
what does the optic disc contain?
optic nerve
| central retinal artery and vein
429
compare the central and peripheral retina
central retina has less photoreceptors per ganglion cells
430
melanopsin
light sensitive pigment that only absorbs 720-480 nm
| contributes to circadian rhythm in SCN of the hypothalamus
431
what wavelength of light can melanopsin absorb?
720-480 nm
432
what is the name give to the light sensitive pigment in the eye?
melanopsin
433
What pigment in the eye contributes to the circadian rhythm?
circadian rhythm
434
function of rods
light intensity
435
quantity of rods
very high except in fovea
436
structure of rods
outer segment has more discs
437
what part of the rods have more discs?
outer segment
438
distribution of rods
mostly in peripheral areas
439
what do rods detect
single photons
440
what is an important characteristic of rods that allows it to detect single photons?
high sensitivity to light
441
describe the acuity of rods
low acuity as they converge onto the same ganglion
442
do rods contribute to colour vision?
NO
443
function of cones
colour and sharp image production
444
quantity of cones
less except at fovea
445
structure of cones
outer segment has less discs - discs contain photopigments
446
what do the discs of cones contain?
photopigments
447
where are cones mostly found?
macula (includes fovea)
448
describe the sensitivity to light of a cone
low
449
compare rods and cones in terms of pigments and signal amplication
cones have less pigments (less discs) and less signal amplification
450
types of cones
3
short - blue - 430
medium - green - 530
long - red - 690 (MOSTLY)
451
what is the most abundant type of cone?
long - red - 690
452
significance of types of cones
allow for high absorption of light in 3 distinct regions
453
how does the brain interpret colour
there is overlap where the incoming light stimulates each cone differently
the brain compares relative stimulation of each type of cone to interpret the colour
454
difference in process of phototransduction of rods and cones
no difference in process
rods - rhodopsin
cones - iodopsin
455
explain the process of phototransduction
1. light triggers conformational change of retinal from cis to trans and activates it into rhodopsin
2. the activated opsin activates transduction which activates PDEs (phosphodiesterases)
3. the activated PDE converts cGMP to GMP and this decrease in cGMP levels causes closure of the Na+ channels which can only be opened when cGMP is present
4. the closure of the channels leads to the decrease in Nt release (eg. glutamate) which causes hyperpolarization (-40 to -70). The degree in reduction of glutamate release determines light intensity/ brightness.
5. graded potentials are then presented to bipolar cells. the decrease in glutamate, increases depolarisation.
6. depolarisation of bipolar cells leads to release of another graded potential to ganglion cells which send action potential through its axons
456
where is rhodopsin found?
rods
457
where is iodopsin found?
cones
458
what is rhodopsin
chromophore
| composed of retinal (vitamin a derivative) and opsin protein
459
what substance inhibits bipolar cells?
glutamate
460
phototransduction - ______ triggers conformational change of retinal from cis to trans and activates it into rhodopsin
light
461
phototransduction - light triggers conformational change of _________________ and activates it into rhodopsin
retinal from cis to trans
462
phototransduction - the activated opsin activates ______ which activates PDEs (phosphodiesterases)
transduction
463
phototransduction - the activated opsin activates transductuction which activates _________
PDEs (phosphodiesterases)
464
phototransduction - light triggers conformational change of retinal from cis to trans and activates it into _______
rhodopsin
465
phototransduction - the activated PDE converts ______ and this decrease in cGMP levels causes closure of the Na+ channels which can only be opened when cGMP is present
cGMP to GMP
466
phototransduction - the activated PDE converts cGMP to GMP and this decrease in cGMP levels causes closure of the _____ which can only be opened when cGMP is present
closure of the Na+ channels
467
phototransduction - the closure of the channels leads to the _________ which causes hyperpolarization (-40 to -70).
decrease in Nt release (eg. glutamate)
468
phototransduction - The degree in reduction of glutamate release determines _________.
light intensity/ brightness
469
phototransduction - graded potentials are then presented to ____ cells.
bipolar
470
phototransduction - the decrease in glutamate, ______ depolarisation.
increases
471
phototransduction - depolarisation of bipolar cells leads to _______ to ganglion cells which send action potential through its axons
another graded potential
472
Colour blindness
inherited absence of one or more types of cones
473
types of colour blindness
protanope - red cone cells defective
deuteranope - green cone cells defective
tritanope - blue cone cells defective
474
protanope
red cone cells defective
475
deuteranope
green cone cells defective
476
tritanope
blue cone cells defective
477
red cone cells defective
protanope
478
green cone cells defective
deuteranope
479
blue cone cells defective
tritanope
480
what determines the eye's sensitivity to light?
the amount of photosensitive pigments
481
dark adaptation
light --> dark
insufficient light to activate cones
must wait for regeneration of rhodopsin
scotopic vision
482
light adaptation
dark --> light
rod cells are bleached
brain switched to cone-only information processing
483
light --> dark
insufficient light to activate cones
must wait for regeneration of rhodopsin
scotopic vision
dark adaptation
484
dark --> light
rod cells are bleached
brain switched to cone-only information processing
light adaptation
485
outline the visual pathway
eye --> optic chiasm --> lateral geniculate nucleus of thalamus --> primary visual cortex --> 2 pathways
1) parietal lobe --> perception of movement
2) temporal lobe --> perception of shape and colour
486
incoming light affects what side of eye
nasal of the same eye
temporal of the opposite
they cross over at the optic chiasm
487
where do neurons involved in the visual pathway synapse
lateral geniculate nucleus of thalamus
488
which axons in the visual pathway decussate?
nasal
489
which axons in the visual pathway do not decussate?
temporal
490
what structure cortically processes neurons of the visual pathway?
lateral geniculate nucleus of thalamus
491
what is the result of the cortical processing of neurons?
topographical maps from patterns of illuminations in order to vender movement (parietal), shapes and movement (temporal) in 3D space
492
significance of topographical maps from patterns of illuminations made by the brain
result of the cortical processing of neurons
| fxn - to vender movement (parietal), shapes and movement (temporal) in 3D space
493
pupil light reflex
shining a light in the eye --> optic nerve sends info to occipital lobe but goes to the edinger-westphal nucleus in the midbrain before going to the lateral geniculate nucleus --> parasympathetics of CN III travel with Va where it synapses at the ciliary ganglion before continuing to the sphincter pupillae which causes the pupil to constrict in both eyes
