week 1 (intro to neurosci) Flashcards
(49 cards)
1
Q
question: what is the difference between sensing and perceiving?
A
- sensory processes = detect info and transform them into bio. sig. interpreted by brain
⤷ can be quantified - perception = awareness of stim. that arises from sensation
⤷ private exp./personal opinion
2
Q
name + define: methods to study sensation and perception (6)
A
-
threshold
⤷ min. amount of stim. needed to be detected -
scaling
⤷ measuring private exp.
⤷ quantifies perception
⤷ how high above threshold can you go (ex. rate pain from 1 - 10) -
signal detection theory
⤷ measuring difficult decisions
⤷ how to decide if you’ve actually seen/exp. a stim. -
sensory neuroscience
⤷ what are the neurons actually doing -
neuroimaging
⤷ what larger parts of the brain are activated during certain things -
computational models
⤷ can you “recreate” w/ a model
3
Q
question: what is the nerve doctrine?
A
- nerve version of cell theory
- says that neurons do not touch each other
- nervous sys. is made up of neurons
4
Q
explain: steps for afferent info
A
- internal and external envrt. (stim.)
- sensory recep.
- sensory ganglia and nerves
- sensory components
- brain
5
Q
explain: steps of voluntary and involuntary efferent info
A
VOLUNTARY = SOMATIC
- brain
- motor components
- somatic motor sys.
- motor nerves
- skeletal musc.
INVOLUNTARY = VISCERAL
- brain
- motor components
- visceral motor sys.
- autonomic ganglia and nerves
- smooth musc., cardiac musc., glands
6
Q
define: transduction
A
- conversion of external E into elec. sig.
- always mediated by ion channels
7
Q
name + explain: types of prot. channels (3)
A
-
ligand gated
- opens w/ ligand binding -
g prot. coupled
- ligand binds to GPCR -> activates G-prot. -> signalling pathway -> opens channel -
stretch/pressure gated
- deforming mem. makes channel open
8
Q
define: receptors
A
- specialised prot. w/ specificity to neurotransmitters
- activation of receptors changes mem. potential
9
Q
name: steps of chemical synaptic transmission
A
- AP arrives at terminal
- depol. -> opens volt. gated Ca channels
- Ca triggers vesicles to fuse
- neurotransmitters diffuse across cleft
- NT bind to receptors on postsynaptic cell
10
Q
question: how to stop the resp. from NT (stop chem. synaptic transmission)?
A
- remove NT
⤷ breakdown w/ enz.
⤷ reuptake into presyn. terminal
⤷ diffuse out
11
Q
question: what causes a synaptic potential?
A
- binding NT to postsyn. receptors
- inhibitory vs excitatory dep. on NT
12
Q
name: types of sensory neuron structures (3)
A
-
bipolar
⤷ usually sensory
⤷ 1 dendrite, 1 axon -
pseudo-unipolar (unipolar)
⤷ usually sensory
⤷ axon branches
⤷ axon on outside (peripheral axon) has dendrites -
multipolar
⤷ usually motor and interneurons
⤷ many dendrites, 1 axon
13
Q
question: what are the principles of sensory coding? (4)
A
-
stim location
⤷ receptive field - intensity
-
duration
⤷ adaptation - modality
14
Q
define: receptive field
A
- neurons are only stim. if a particular area on the corresponding surface is stim.
- for touch + vision
15
Q
question: how does the intensity of stim. affect the AP?
A
- smaller stim. -> smaller receptor potential -> slower AP -> slower resp.
- vv for larger stim.
16
Q
define: adaptation (neurons)
A
- continued exposure to a stim. causes reduced awareness
17
Q
explain: pathway of sensory input through brain (general)
A
- all sensory input goes to primary receiving areas = cortexes
- transmitted to other cortical areas = association areas
18
Q
explain: struc. of cortex
A
- sheet-like array of neurons
- 6 layers
⤷ neocortex - cerebral cortex = gray matter
19
Q
explain: func. of thalamus
A
- all sensory sig. go through thalamus to get to cortex
20
Q
question: what are the parts of the brainstem (from top/sup. to bottom/inf.)
A
- midbrain
- pons
- medulla
21
Q
question: which cranial nerves are exclusively for sensory info, motor info, and both?
A
SENSORY
- I - olfactory
- II - optic
- VIII - vestibulocochlear
MOTOR
- III - oculomotor
- IV - trochlear
- VI - abducens
BOTH
- V - abducens
- VII - facial
- IX - glosspharyngeal
- X - vagus
- XI - accessory
- XII - hypoglossal
22
Q
define: ganglion
A
- local accumulation of neurons and glia in PNS
23
Q
define: segmental/spinal/peripheral nerves
A
- bundles of peripheral axons covered by glial cells
- 31 pairs
24
Q
question: what is the diff. between intracellular and extracellular recording?
A
INTRA
- pokes cell w/ electrode
- compares volt. inside vs outside cell
- sig. amp. = 1 - 100 mV
EXTRA
- electrode is near cell
- compares activity near cell vs distant (inactive) place
- sig. amp. = 10 - 500 uV
25
question: pros and cons of intracellular electrophysiological recording?
PROS
- can record graded synaptic and receptor potentials
- good spatial and temporal resolution
CONS
- invasive
- only 1 neuron at a time
26
question: pros and cons of extracellular electrophysiological recording?
PROS
- less invasive
CONS
- can't record receptor potentials
⤷ only generally around cell
27
name: types of neuroimaging (5)
1. **EEG** - electroencephalography
2. **MEG** - magnetoencephalography
3. **MRI** - magnetic resonance imaging
4. **fMRI** - functional magnetic resonance imaging
5. **PET** - positron emission tomography
28
question: (compare) how does each type of neuroimaging actually measure brain activity?
EEG
- electrodes placed on scalp
MEG
- person inside machine (only head)
- measures changes in magnetic fields of neurons
MRI
- person inside giant magnet
- sensors detect E released as atoms realign after being affected by giant magnet
- measures water rich tissues (bc H atoms)
fMRI
- magnetic pulse picks up areas where brain demands more oxygen (more active areas)
PET
- inject tracer into bloodstream
- camera detects radiation from tracer
29
question: pros and cons of EEG
PROS
- less invasive
- high temporal resolution
CONS
- low spatial resolution
⤷ shows populations of neurons (less detail)
30
define: event related potential
- EEG
- avg. activity from several resp. to the same stim.
31
question: pros and cons of MEG
PROS
- good spatial resolution
- can see deeper subcortical struc.
CONS
- very costly
32
question: pros and cons of MRI
PROS
- good detail
- no radiation (less invasive than X-ray)
- better for soft tissues (compared to X-ray)
- several images can be used to reconstruct 3D image
CONS
- only structural
- very loud (can't do aud. stim.)
- claustrophobic machine
- patient needs to be very still
33
question: pros and cons of fMRI
PROS
- can record func. info
- good for deep struc. (subcortical)
- less invasive
CONS
- low temporal resolution
⤷ bc relies on blood flow so it's indirect activity of neurons
⤷ some delay
- same other CONS as MRI (loud, etc.)
34
question: pros and cons of PET
PROS
- not loud
- good for deep struc. (subcortical)
CONS
- invasive
- low spatial resolution
⤷ compared to fMRI
35
define: mathematical models
- using math to closely mimic psych. and neuronal processes
36
define: computational models
- use math to decribe steps in physiologyal and/or neural processes
- on computer
- may be used to predict resp. (can learn from info.)
37
define: efficient coding models
- compresses redundant info and focues on areas w/ important info
- assumes sensory sys. are already used to the predictability of natural environments
38
define: bayesian models
- assumes earlier observations should bias expectations for future events
- use prior exp. to make predictions for the future
- uses errors to adjust and improve for the future
39
define: artificial neural networks and deep neural networks
- layers of heavily interconnected computational units (like neurons)
- strength of connections can increase/decrease w/ experience (like learning)
- deep neural networks = subcategory
⤷ many layers of units with millions of connections
⤷ good for classifying into categories
40
question: what are the components of a neural network?
- inputs
- weights
⤷ how important the input is to the outcome
- threshold
⤷ min. output needed for data to be sent to the next layer
- output
41
define: psychophysics
- quantitative relationship between physical stim. and psychological exp.
- by Fechner
42
question: why do we relate physical stim. to perceptual exp. w/ math models?
- to compare diff. indiv.
⤷ and help ID abnormalities
- to quantify diff. between stim.
43
describe: relationship between stim. intensity and sensation magnitude for linear, exponential, and log func.
LINEAR
- direct relationship
EXPONENTIAL
- near start/origin: big change in intensity = small change in sensation
- near end: small change in intensity = big change in sensation
LOG
- near start/origin: small change in intensity = big change in sensation
- near end: big change in intensity = small change in sensation
44
question: in functions, why don't they start at the origin?
- no stim. = no sensation
- doesn't reach threshold to be detected
45
question: subthreshold vs suprathreshold?
- sub = below level of detection
- supra = above level of detection
46
name: ways to measure thresholds? (3)
1. **adjustment**
⤷ adjust stim. to be just able to detect it
⤷ less detailed bc no defined values
2. **limits**
⤷ stim. starts very intense and progressively gets less and less until cannot be detected anymore (vv)
⤷ has defined values to test
3. **constant stimuli**
⤷ no consistency to stim. presentation
⤷ diff. intensities in random order
47
question: which method to measures threshold is best?
- constant stimuli
- adjustment and limits are predictable
⤷ can influence results -> bias
48
question: what type of data does psychophysics generate in ideal situations? what about in reality?
IDEAL
- step wise func.
- always sense suprathreshold
- clear diff. between yes and no stim.
REALITY
- psychometric func. (s-shaped)
- uncertainty around stim. intensities near thres.
- use 50% resp. lvl as abs. thres.
49
question: why does stim. intensity vary around 50%?
- cog. factors at play
⤷ ex. how much attention being given, if participant is bored
- physiological factors
⤷ stim. might vary
- biological sys.
⤷ neurons aren't perfect
