Bilkey Flashcards
how many pairs of spinal nerves do we have?
31
how many cranial nerves do we have?
12
what is a sensory dermatome?
an image that describes where the sensory nerves synapse in the spinal cord
what are the two divisions of the forebrain?
telencephalon and diencephalon
are there more neurons lower in the neocortex or less?
less; there are less individual neurons lower in the neocortex and more nerve fibres that form
what are the ion concentrations of sodium and potassium of a neuron cell?
positive charge OUTSIDE the neuron and negative charge INSIDE the neuron
what does the Hodgkin/Huxley cycle describe?
that if an EPSP depolarises a nerve cell, more channels will be opened leading to larger depolarization of the nerve cell to create a positive feedback loop
what axon-related dysfunction is related to multiple schelorsis?
demyelination of nerve axons
do rods or cones have high acuity?
cones
which photoreceptor is more highly concentrated on the fovea?
cones
what is the fovea?
the spot on the retina where light hits when we focus on an object
what is another name for the high acuity vision cones have?
phototopic vision
what is another name for the low acuity vision cones have?
scotopic vision
what does it mean for rods to have a lower visual acuity?
they can be activated by lower light levels
why can rods work at nighttime but cones can’t?
because cones require higher light levels that are not there at nighttime, rods do not require this high light stimulation
why is the stuff we see in our periphery blurry?
because rods are concentrated on the peripheral retina which have a low visual acuity
which form of photoreceptor tends to activate a small number of bipolar cells?
cones
which photoreceptor is better at amplifying their information to many retinal ganglia cells?
rods
what are the 2 types of photoreceptors?
rods and cones
what is spatial frequency?
how detailed an image is based on how much light is sensed
what is high spatial frequency?
when an image has higher details (more specific) but less colours
what is low spatial frequency?
when an image has less details but more colour
why does Mona Lisa seem like she is smiling and not smiling at the same time?
because at a high resolution, she is not smiling (fovea) but our peripheral cells notice the lower resolution in which she is smiling
what area of the retina allows us to see high spatial resolutions?
fovea
what are intrinsically photoreceptive retinal ganglia cells (ipRGC)?
specialised retinal ganglia cells which also notice light, more dominantly blue light by using melanopsin photopigment
where do ipRGC transduce their information?
to the SCN to help govern the sleep/wake cycle
where in the retina are ipRGC found?
bottom, front
what colour light is dominant in the early morning?
blue (hence use of ipRGC to djust our sleep/wake cycles)
what neurotransmitter do RGC’s and photo transmitters mainly release?
glutamate (depolarisation)
what neurotransmitter do bipolar cells mainly release?
GABA (hyperpolarisation)
what is lateral inhibition?
the phenomenon where a neuron’s response to a stimulus is inhibited by a neighbouring stimulus
why does lateral inhibition occur?
because images that receive brighter light in the periphery will activate more inhibitory horizontal cells which makes the image seem dimmer compared to the one next to it
what is an opponent process?
when there are two systems competing to represent the world, for example:
- off/on centres of receptive fields
- approach-avoidance conflict
- homeostasis
- lateral inhibition
how do Mach bands demonstrate opponent processing?
the bands that form do not exist, but because the dark and light colours are placed next to each other, the left side seems darker and the right seems lighter
what is the frequency of purple light?
400nm
what is the frequency of red light?
700nm
is red light or purple light a higher frequency?
purple
what are the 3 main types of cones?
blue, green, red
what is deuteranomaly?
colour blindness weak in green perception (most common)
what is protanopia?
colour blindness weak in red perception
what are the two opponent systems of colour?
red-green and blue-yellow
what are the 5 examples of opponent processing Bilket discussed?
- simultaneous contrast
- Mach bands
- colour perception
- homeostasis
- motivation
where do most of the neurons in the retina send through axons?
to the lateral geniculate nucleus (LGN)
what is retinotopic mapping?
idea that the way we see the world is also organised in how the information is understood in the brain
what is the main difference between simple and complex cells found in the V1?
simple cells have on/off areas where they only respond if light hits them a certain way but complex cells will respond if light falls on them at any area
what is meant by the columnar architecture of V1?
that the cells are close to each other in V1 are responsible for transmitting information about the same region of a visual field
why is the LGN topographically represented?
reduces axon volume which reduces overall brain volume
where do most auditory stimuli travel through before reaching the primary auditory cotex in the brain?
the medial geniculate nucleus (MGN)
what is top-down processing vs bottom-up?
when you use prior knowledge and experience to help you understand the world and novel experiences, bottom-up is using the new information to better understand the world
do humans do more top-down or bottom-up processing in our visual system?
top-down processing
why do humans do more top-down processing than monkeys?
because humans have more brain tissue dedicated in the surrounding tissues of the auditory system, not in the actual primary auditory cortex (like monkeys)
what is the McGurk effect?
that we will perceive an audible stimulus using visual information (‘ba’ and ‘va’ experiment)
what does the dorsal stream from V1 share information about?
the movement of an object
what does the ventral stream share information about?
the object’s features: shape, colour, size
what did researchers learn about facial recognition in monkeys a long time ago?
that they have specific neurons in their IT that fire at different points of a monkey’s head turning
what was the method of the Quironga study about Jennifer Aniston cells?
showed people 100 images and recorded how their V1 neurons fired in response to these images
what were the results from the Quironga study about Jennifer Aniston cells?
- invariance: that the cells fired despite how the image of Jennifer Aniston was changed
- local coding theory
what is the local coding theory?
that a small number of cells in the V1 fire and give you the perception and recognition of an object eg Jennifer Aniston
what are the advantages and disadvantages of the local coding theory?
adv: means the neurones are separated so they don’t mix up the people you see
disad: it doesn’t support the idea of object generalisability or pattern completion
what is pareidolia?
seeing faces in inanimate objects
what is the dense encoding theory?
that many cells have components of the representation of something and the pattern of firing is unique to each situation
what did Doris Tsao find in her experiments of facial recognition?
the main points that make up a face are processed by specific V1 neurons, and the firing sequence of these neurons leads to the recognition of faces
what does V5 process?
movement
what does V4 process?
colour and form
what is akinetopsia?
not seeing movements as fluid movements, but as many still images (Patient MP)
why is it beneficial we can see motion?
- captures attention
- separates back from front
- distance from objects
- 3d shape of an object
- recognition of objects
what is looming?
when you detect a change in an object as you get closer to the object (truck thing)
what is the binding problem?
the problem the brain faces in representing different elements of an image in different areas of the brain, but somehow still is able to make all the information merge into one representation
what is temporal binding?
that neural responses are tied together by the simultaneous firing of their axons
what is schizophrenia?
A disorder characterized by abnormalities in perception, cognition, and emotion due to high levels of dopamine
what are some typical features of a schizophrenic brain?
- enlarged ventricles and less brain mass
- loss of dopamine activity
- less GABA and glutamate activity
why do schizophrenic people take more time to work out a Mooney face?
because they have reduced brain wavelengths
why do schizophrenic brains have a reduced ASSR (auditory steady-state response)?
ASSR sends signals to the brain, and schizophrenic brains have less response to these
what is Atkinson’s multi-store model of memory?
that sensory memory becomes short term memory which if rehearsed becomes long term memory, and if not is lost
how is a memory collected in the brain?
every psychologically significant event and sensation is the result of a particular pattern of activity in a group of interconnected neurons
what is the idea of reverberating neural activity in a closed loop circuitry?
how short term memories are recorded in the brain, when an experience happens, a network of axons fire repeatedly, but this must be consolidated to turn into a long term memory
how can a weak connection become stronger, according to Hebb?
if a weak synapse is present at the same time as a strong synapse, the weaker one will become stronger
what is Hebbian learning?
when the postsynaptic and presynaptic cells fire together, then the connection between them is strengthened
what is long term potentiation?
a high frequency electrical pulse given to a neuron to strengthen its synapse, and once it is strengthened, it stays strengthened
how does the LTP induction mechanism work?
- the AMPA glutamate receptor lets in glutamate, and magnesium blocks it, a strengthened synapse gets rid of the magnesium, to allow for more calcium to enter the postsynaptic cell
NMDA antagonists block __________
learning
disrupting LTP maintenance produces _________
forgetting
what is long-term depression?
works alongside LTP to prevent over-excitation in neural circuits
what parts of HM’s brain were removed?
temporal lobe, hippocampus, adjacent cortex
what is anterograde amnesia?
can’t make new memories
what is retrograde amnesia?
forgotten some memories before the accident
what is explicit/declarative memory?
memory about events and facts, governed by the medial temporal lobe and diencephalon
what is implicit/nondeclarative memory?
procedural memories (skills and habits), priming, learning
what happened to Patient RB?
heart surgery lead to loss of blood flow to the hippocampus and surrounding structures, had amnesia then died
what happened to Patient NA?
fencing sword through the brain, damaged the thalamus and mammillary bodies leading to memory deficits
what is Wernicke-Korsakoff syndrome?
syndrome that usually happens in heavy drinkers because it is caused by a lack of thiamine (vitamin B1) in one’s diet, causes bad memory after damage to mammillary bodies and thalamus
how does the hippocampal-diencephalic memory system work?
information enters the association areas –> hippocampus –> fornix –> mammillary body –> thalamus to the neocortex for consolidation
what is egocentric space?
when you orient yourself based on your own location
what is allocentric space?
when you orient yourself based on the location of landmarks around you
if you place a rat in the same location for each trial in the Morris Water Maze, what form of direction will it use to navigate itself?
egocentric space, because it can use the starting point as a reference point
if you place a rat in different locations for each trial in the Morris Water Maze, what form of direction will it use to navigate itself?
allocentric space, because they would use landmarks to find the platform not its own location
what area of the brain is responsible for processing spatial information?
hippocampus
in the Morris-Bath test, which hippocampal-damaged rats were the most disadvantaged? the rats that started egocentrically or allocentrically?
allocentrically, because hippocampal damage processes allocentric information more than egocentric information
what kind of spatial awareness are taxi drivers thought to be superior in and why?
allocentric, because they train up their cognitive map of towns, and have to use landmarks to get around
what were the significant brain mass differences between taxi drivers and controls?
taxi drivers: larger posterior hippocampus, smaller anterior hippocampus compared to controls
what are place cells?
potentially cells in the hippocampus that can remember the location of things, represent the space one occupies
people with damage to what area of the brain struggle to predict the time things take?
hippocampus (Patient HM struggled to tell the time)
what are time cells?
cells in the hippocampus that code the length of a period of time
what study on rats is used to support the idea of time cells?
rats run on treadmill with their brain’s monitored, found that the same cells fired every 12 seconds no matter how fast the mouse was running
what is the scalar expectancy theory (SET)?
the theory that we have a pace tracker in our brains, and when you are asked to time an event, you turn it on, so you can guess how much time has passed
can people’s SET’s differ?
yes
what drug has been found to alter time perception?
THC (the active component in marijuana)
why is it thought that people’s perception of time slows down when they are in a near death experience?
could be a result of one’s pacemaker changing to chop up their perception of time into smaller chunks, meaning events take longer
Fearfall study testing time cells found that…
people’s time estimation was longer post-fall, so in highly adrenaline provoking events, time seems to slow down
what is chronostasis?
the idea that time stops when you make a rapid eye movement. No visual information goes to the brain when you blink, but the brain fills it in
what is the flash-lag illusion?
A non-moving object is flashed next to a moving object which makes us think the nonmoving object is lagging behind the moving object so it looks like it’s behind it
why does the flash-lag illusion occur?
because the nervous system is slow in picking the nonmoving object up and follows the moving object so closely (activates V5) ie pays closer attention to the moving object than the nonmoving
what is memory reactivation?
the idea that patterns in the brain are ‘reactivated’ when they are remembered
what is memory reconsolidation?
the process whereby a memory is consolidated from short term into long term memory, and then when it is remembered, it is brought into an active state where it can undergo change before it is reconsolidated into long term memory
how does adrenaline effect memory formation?
remember events much more vividly than those who weren’t emotionally affected (9/11 study)
what is episodic future thinking, and what area of the brain corresponds with it?
Imagining or simulating a specific episode that might occur in one’s personal future; medial temporal lobe
what is dementia?
when a person experiences gradual loss of brain function due to physical changes in the structure of their brain
what is the phonemic and semantic verbal fluency task (SVF)?
A test widely used to test an individual’s memory ability, people with Alzheimer’s have worse results
what are beta-amyloid plaques?
clusters of beta-amyloid (broken up APP) that is associated with Alzheimer’s disease
what are neurofibrillary tangles?
tangles of microtubules caused by the inactivation of Tau proteins
what is a possible treatment for Alzheimer’s that targets the brain’s production of Ach?
inhibit the cholinesterase enzymes (like Ach-E) to give the Ach more time to hang out in the synaptic cleft to fill the available receptors
what do Tau proteins do?
stabilise the microtubules
where do neurofibrillary tangles first appear in early AD?
perirhinal areas (supporting hippocampal) and then goes onto affect the hippocampus
what does the APOE gene do?
determines what kind of APOE protein is produced (E2, E3, or E4) and this is responsible for transporting cholesterol to neurons
what does the APOE gene do?
determines what kind of APOE protein is produced (E2, E3, or E4) and this is responsible for transporting cholesterol to neurons
which APOE variant leads to higher likelihood of Alzheimers?
E4, especially if two E4 alleles are inherited from parents
what happens to those with an E4 variant of the APOE gene?
E4 variant means people will have a cholesterol accumulation and impaired beta-amyloid clearance, more reactive microglia, disrupts the BBB, and increased synapse formation in neurons.
what did the Nun study teach us about the brain?
found that people without intellectual language had more neurofibrillary tangles in their brains
what is cognitive control?
the set of psychological processes that contribute to planning, controlling and regulating the flow of information processing, and these processes bias our actions and thoughts
what are delay cells?
cells in the prefrontal cortex (PFC) that respond only in the delay period after a stimulus, potentially to help the short term memory in remembering things they just saw
what is the n-Back test?
test of working memory and false memory formation due to lures, activates PFC
what is inhibitory control?
to be driven solely by the stimuli in the environment
what is the Wisconsin card sorting task?
Task where you are given four piles of cards and you have to sort them but aren’t initially told how to sort them. You do trial and error until you figure out how they are sorted, but after you’ve done a few correct rounds, the rules change, and you must figure out the new rule.
people with damage to what area of the brain sucked at the Wisconsin card game?
PFC damage
what is self control?
when previously reinforced, highly reinforcing, or well-learned habitual responses are suppressed
what is set-shifting?
when the immediate goals no longer get you to your long-term goal, so you need to change the short-term goals to redirect your purposes
what is the trail making test?
test for set-shifting: the subject is instructed to connect dots and then the rule changes to connect letters - like in set-shifting, you change your short term goals when they no longer line up to the long term goal
abstract vs concrete thought?
abstract: use concepts to make and understand ideas, not the same for everyone
concrete: things that are objective eg a red traffic light means to stop
what are rule responsive neurons in the PFC?
neurons that fire based on the rule of what context you are in, so they remind you what the ‘correct’ choice is in every context eg social rules
people who struggle with abstract thought and goal planning often have brain damage where?
left lateral PFC
how might the PFC inhibit creativity?
the PFC could be constraining you on expressing your creativity because it always is reminding you of the social ‘rules’ to stay within, by inhibiting the PFC a wee bit, people could be more creative.
why don’t people like the term ‘executive function’ when considering cognitive control?
insinuates the idea of a homunculus
what is system 2 of the dual systems model of decision making?
the kind of decision making where you rationally go through each decision, very analytical, a lot of energy and attention, slow
what is system 1 of the dual systems model of decision making?
“gut instinct”, processes the info and gives back feedback effectively, mainly automatic, not much processing, heuristics, low energy cost
what is temporal discounting?
idea that something is of greater value if it is available sooner rather than later
what is the exploit-explore trade-off?
the trade-off we use when decision making - between using energy actually using a resource to inform us and using energy to find new resources
what is the marginal value theorem?
finds the optimal time it takes to use a resource before you search elsewhere
what is Kluver-Bucy syndrome?
in animals, due to damage to amygdala, increased sexual activity, lack of fear, crazy
what processes are the ventral medial PFC (vmPFC) thought to be associated with?
planning of events and remembering pleasant memories, triggering somatic responses to reward stimuli and punishment
what is Damasio’s somatic marker hypothesis (SMH)?
the key idea is that when one’s decision is uncertain, one’s emotions and feelings are essential in the making of the decision; this is why people with PFC damage didn’t show any emotional responses to arousing stimuli
what happened in the Iowa Gambling task?
people with amygdala damage didn’t show any difference in skin conductance (measure of one’s feelings of anxiety) when choosing the high risk vs low risk deck, but in controls, skin conductance was higher for the high risk deck; shows lack of emotional awareness
reactive fear vs cognitive fear
reactive is the fear felt in escaping decisions and cognitive fear is a low buildup of fear involving decision-making and planning
what is social cognition?
how people process, store and apply information about other people are social situations
what are the seven key components for successful human interaction?
- social perception
- social inference
- social learning
- social signaling
- social drives
- social identity
- integration of social cues
what is the simulation theory?
idea that some aspects of our ability to understand others is based on our ability to MIMIC their experience – to mentalize and empathize
what are mirror neurons?
neurons in the brain that fire when someone does something, shows how good we are at observing others, could be the basis of empathy
what is the faux pas test used for?
tell someone a situation and test their ability to notice the socially strange thing - people with mPFC lesions struggle to understand WHY people do things socially
what is the social control hypothesis of social connection/isolation ?
that socialising is good for our wellbeing because having family and friends around influences our health behaviours like sleep and diet
what is the evolutionary hypothesis of social connection/isolation ?
that being social was evolutionary selected for because it allows us to be closer with others for safety
what is epigenetics?
when environmental factors affect how genes are expressed and passed on
what are the 3 important aspects of consciousness?
sentience, self-knowledge and access to information
what is sentience?
an aspect of consciousness: one’s subjective experience, so what you experience, anger, pain, etc
what is self-knowledge?
one of the 3 aspects of consciousness: the awareness of how unique you are, or how unique others are
what is access to information?
an aspect of consciousness: the ability to communicate how one’s brain works personally
what did the Rhesus monkeys suggest?
showed some kind of self awareness because the monkeys were more correct when they chose to take the test vs when they were forced to
hypnogogic state vs hypnopompic state?
Hypnogogic state: falling asleep
Hypnopompic state: waking up
what is the neural correlate of consciousness ?
asks the question if there is a neural part that is responsible for consciousness; tested using bistable tasks to see what people perceive
what is a bistable task?
used to test consciousness, compares brain activity during perceptual changes and when it doesn’t change, sometimes there can be changes in the conscious experience even when the physical stimulus doesn’t change
how is REM sleep related to consciousness?
effective connectivity is damaged during non-REM sleep, thus the impairment of the ability to integrate information may cause the fading of consciousness ie less REM sleep may lead to lowered consciousness
what is lucid dreaming?
when you are conscious you are dreaming within the dream; increases the BOLD signal
