Cognitive Neuroscience Flashcards
Cognition
Interpretation of transformation of recently acquired or stored information
Phrenology
Proposed that activation of brain areas makes them expand, which results in changes of skull shape. According to phrenology functions (traits) are highly localised – localisationist’s view
What did Marie-Jean-Pierre Flourens do?
Lesioned various parts of pigeon brains and didn’t find evidence of specific behavioural deficits due to any of the lesions
He concluded that behavioural abilities are made by interactions of areas from the entire brain - aggregate field theory
What did John Hughlings Jackson do?
Monitored epilepsy patients and realised that seizures often resulted in ordered jerks of the muscles. This led to the idea of a topographic organisation of muscle representation in the cortex - localisationist view
The neurone doctrine
Neurones are separate units
What did Golgi and Cajal win a Nobel prize for in 1906?
Arguing that the nervous system is made up of discrete individual cells (neurone doctrine)
Glial cells
Oligodendrocytes myelinate axons in the brain and spinal cord
Schwann cells myelinate axons in the periphery of the body
There are more glial cells in the brain than there are neurons
What functions do glial cells serve?
Getting nutrients from the blood
Maintaining the blood-brain barrier
Stop toxins from entering the brain and insulator cells
Briefly summarise the role of each part of the neurone
Dendrites receive the message
The soma (cell body) converts the message
The axon sends the message
Resting membrane potential
Resting potential is -70 mV
The neurone is negatively charged on the inside because it contains a lot of proteins and most proteins are negatively charged, it also has a pump
What is the role of the sodium-potassium pump?
Potassium tries to get out and sodium tries to get in and the pump works to maintain this negative energy
Synaptic transmission
At the synapse the action potential hits the membrane of the axon terminal, and it depolarises the membrane
Makes the inside more positive, which causes channels to open so calcium ions flow into the cell
Vesicles that contain neurotransmitter, once calcium binds with them they can then bind with the cell membrane then are able to release their neurotransmitter into the synaptic cleft
Neurotransmitter binds with receptor dendrite
Channels on postsynaptic terminal open which means sodium can now enter the postsynaptic cell which could trigger an action potential which would then move to the next neurone
Central nervous system
The brain
Spinal cord
Functional neurosurgery
Altering the activity of a brain area by either using ablation (removing), electrical or pharmacological methods to establish overall more normal patient function
Single dissociation
An acquired disability that affects only one are of functioning without impairing any other area of functioning
Transcranial magnetic stimulation (TMS)
Low-level currents that result in action potential under the anodes
Works to activate or inactivate parts of the brain and do this whilst subjects perform a certain task to see what the effect of this is on their functioning
Attention
The process by which the mind chooses from among the various stimuli that strike the senses at any moment
Dichotic listening
When you get one stimulus in one ear and a different one in the other and you have to ignore one of the stimuli depending on which stimuli you need to focus on
Exogenous attention
Transient, bottom-up, automatic
Endogenous attention
Sustained, top-down, voluntary
Covert attention
When you fixate somewhere and attend elsewhere
Overt attention
When you fixate and attend in the same place
Spatial attention
Attention to a specific location in space, irrespective of what is present at that location
Feature based attention
Attention to specific stimulus features irrespective of where they are in our environment
Object based attention
Attending to a whole object, even if only parts are relevant
What was Thales’ monistic perspective?
That the flesh and blood brain produces thoughts
That the conscious mind is a product of the brains physical activity and not separate from it
What is Franz Joseph Gall known for?
Believed innate functions were localised in specific brain regions in the cerebral cortex
Hypothesised that if a person used a specific faculty more then that part of the brain would grow and there would be a bump in the overlying skull so Gall believed that by carefully analysing a skull he could understand the personality of a person - he called this technique anatomical personology
This idea was later coined as phrenology
What is Flourens known for?
The first to show that certain parts of the brain were responsible for certain functions by destroying parts of pigeon and rabbit brains to observe what happened
Concluded advanced abilities like memory are more scattered throughout the brain
What is aggregate field theory?
The idea that the whole brain participates in behaviour
Who coined the localisationist view of the brain?
John Hughlings Jackson
what is the homunculus?
topographic organisation of muscle representation in the cortex
Broca’s area
language production
Wernicke’s area
language comprehension
the neuron doctrine
neuro system is made up of discrete individual cells
who won a Nobel prize in 1906 for the neuron doctrine?
Golgi and Cajal
oligodendrocytes
myelinate axons in the brain and spinal cord
schwann cells
myelinate cells in the periphery of the body
microglial cells
immune response in the brain
glial cells
more glial cells than neurons in the brain, get nutrients from the blood and maintain the blood brain barrier
soma
cell body
resting membrane potential
-70mV
where is the neuron more negative when resting?
inside the neuron, made more positive with action potential
which is the first channel to open during action potential?
sodium ion channels
which ions bind to the vesicles in the synapse?
calcium ions
coronal brain section
view from side of the brain
sagittal brain section
view from top of the brain
caudal
posterior (back of the brain)
dorsal
superior (top of the brain)
rostral
anterior (front of the brain
ventral
inferior (bottom of the brain)
gyri
wrinkles in the brain
how does MRI distinguish white and grey matter?
uses differences in the amount of water and fatty tissue in the brain
Posner’s Letter matching task
two letters on the screen and the participant has to press ‘same’ or ‘different’
findings of Posner’s letter matching task
processing time differs depending on which letters are represented, Posner argued that the different latencies represented the degree of processing required to do the letter matching task, stimulus identity representations are activated first, phonetic representations second and categorisations are last
neurology
understanding the brain based on brain damage and disorders
raster plot
plot of action potentials, recorded as time after an external event, every time an action potential is recorded you mark it on the plot
alzheimer’s disease
degenerative, tangles and plaques in limbic and temporo-parietal cortex
Parkinson’s disease
degenerative, loss of dopaminergic neurons
Electroencephalogram (EEG)
electrodes attached to the head to measure electrical activity in the brain - relatively cheap, non-invasive, fairly good signal
Event related potentials (ERP)
average of EEG recordings which may allow a pattern from a stimulus to appear
optogenetics
using light to manipulate neuronal activity
transcranial magnetic stimulation (TMS)
inducing a magnetic field into the brain to excite the underlying tissues - can create virtual lesions, can excite or inhibit certain areas of the brain
how does MRI work?
hydrogen are disturbed by a signal and are flipped, then this is stopped and we measure how long it takes for them to flip back, different time depending on whether it is white or grey matter, used to plot the brain
what does BOLD stand for?
blood oxygen-level dependent
Feature based attention
Ability to attend to specific features, across the visual space
Object based attention
Attention to sub parts of an object, ensures that other parts of that object are automatically better processed as well
Attention
Attention is the process by which the mind chooses from among the various stimuli that strike the senses at any given moment.
Astrocytes
Large glial cells that create the blood brain barrier
Dichotic listening task
One stream of information in one ear and another stream of information being played in the other
Evidence for early selection
- auditory cortical responses are affected by attention, e.g. the cat, when it pays attention to the mouse the response to the sound being played is not as big
- auditory brainstem responses are not affected by attention
- dichotic listening task, less response of ERP to the unattended input, modulated by attention as person is listening to the other input
otoacoustic emissions
sound that your ear reflects back out after hearing something
exogenous attention
transient, bottom-up (something in the external world), automatic
endogenous attention
sustained, top-down (willful act by ourselves), voluntary
ERP evidence for endogenous visuo-spatial attention
when the cue and the target match we get a big signal from attending to the right area that they chose to attend to - also evidence for early selection
What do single cell electrophysiology experiments show about spatial attention?
Neurons fire more when we attend to the receptive field
Retinotopic mapping
How is how the retina is represented across the surface of our brain, the orderly representation of the external world in the cortex
Biased competition model of attention
Neurons compete for processing resources. Feedback from ‘higher areas’ selectively boosts those neurons that process stimuli at the attended location. These in turn suppress their competitors. Biased competition is an example how attention selectively filters incoming information.
What are the two main visual processing pathways in humans?
Ventral pathway (goes to inferior temporal lobe) and dorsal pathway (goes to posterior parietal)
What are the feature maps in the visual cortex?
Describes that specific features are represented in specific areas
fMRI evidence for feature selective attention in different human brain areas
When attending to motion, areas that process motion show more activity
Evidence for object based attention representation in the brain
When someone is told to attend to a certain object if there is an invalid cue on the same object it is slower than a valid cue on the right object but faster than if it is invalid cue and not on the same object
Why do we need spatial working memory?
To remember where he cue has told us to attend to
What does a response after cue offset mean?
Delineates the attentional control network
What does response related to stimulus onset mean?
Delineates areas activated by stimulus and task
Which brain regions is the top-down attentional network in?
Fronto-parietal network with superior parietal lobule and the frontal eye field
Which brain areas are involved in the bottom-up network for novelty and attentional reorienting?
Temporo-parietal junction and ventral frontal cortex
Parts of the monkey attentional network
Frontal eye field (motor)
Posterior parietal cortex (attention)
Primary visual cortex (sensory)
Which brain area is involved in directing attention to what is relevant to us, early visual processing?
Superior colliculus
Which brain region does top-down attention reside?
Posterior parietal
Which region is the frontal eye field in?
Superior frontal cortex
What does extinction mean?
If you wiggle your fingers someone with extinction will only point to one side that is more dominantly processed for them -imbalanced perception
What does neglect mean?
People with neglect may ignore one side of their surroundings completely and not perceive it at all
Unilateral spatial neglect
When someone doesn’t perceive or even have a representation of half of their world
Why is the phenomenon extinction named that?
Because the presence of a stimulus in one side of their visual field causes the other stimulus in the other side to be extinguished from awareness
Neuropsychological test for neglect or extinction?
Line bisection test
Redrawing an image
Circling Os or Cs
Gaze bias - people with extinction look all at one side
Declarative/ explicit memory
Something we can talk about
Events (episodic memory)
Facts (semantic memory)
Nondeclarative/ implicit memory
Procedural memory
Perceptual priming
Classical conditioning
Non associative learning
Sensory memory
Iconic (visual)
Echoic (auditory)
How long is the capacity of our echoic memory?
Around 12 seconds - evidence from measurements showing no surprise after a 12 seconds because there is no automatic memory of the deviant sound anymore
The hierarchal (serial) modal memory
Sensory input
Sensory register
(Attention)
Short term memory
(Rehearsal)
Long term memory
Atkinson and Shiffrin modal model
Working memory model
Proposed by Baddeley and Hitch
Visuospatial sketch pad
Central executive
Phonological loop
Brain areas in phonological loop:
BA44 - Broca’s area 44
Supramarginal gyrus (part of higher auditory cortex)
Visual spatial sketchpad
Mostly located in right hemisphere, frontal and parietal cortex
Evidence of how people with no hippocampus perform on procedural learning
They show faster reaction times in a procedural task as it is repeated more even if they can’t remember doing it
Priming
Change in the response to a stimulus, or in the ability to identify a stimulus, following prior exposure to that stimulus
Fornix
Big loop of fibre bundles that helps to connect the different parts of the brain
Anterograde amnesia
Can’t make new long term memories
Retrograde amnesia
Can’t remember things from the past, most recent things usually forgotten first
Patient HM
Epilepsy
Hippocampus removed
Can no longer form new memories
Study with monkeys on delayed non-match to sample
Have to pick which one doesn’t match from remembering the first item
With no lesion the monkey performs the task well
Hippocampus removed doesn’t perform as well
With multiple lesions the effects start earlier and deficit is worse
Lesions that cause severe anterograde amnesia
Dorso medial nucleus of thalamus
Mammillary bodies
Korsakoff syndrome
Vitamin B1 deficiency which damages dorsomedial nucleus of the thalamus and the mammillary bodies and causes amnesia
Critique of modal memory model
Short term memory not required for long term memory
Patient with severe STM deficits retained significant LTM
But did still have some STM digit spam so some STM may be intact
Patient EE
Short term memory deficits
Digit span of 1-2
Due to a tumour
Retained LTM
Evidence of different storage for semantic and episodic memory
HM could still draw his old flat so suggests different storage for semantic and episodic memory
Patient KC
Anterograde and retrograde amnesia
Lesions found in many parts of the brain but they were particularly prominent in the medial temporal lobes
Despite the dense episodic and source amnesia, K.C. was still able to learn semantic facts, even if at a slower pace. His forgetting rate was similar to controls
Familiarity
a form of memory stored in and around the entorhinal cortex
Evidence of familiarity in the entorhinal cortex
More activity in fMRI during encoding shows the participant will then be more familiar with that item
If they have low confidence on whether they’ve seen the item or not there was low activity during encoding
What is encoded in the entorhinal cortex?
Familiarity
Process of encoding episodic memory
Starts form association areas in the frontal, temporal and parietal lobes
Where = parahippocampal
What = perirhenal cortex
Then to entorhinal cortex
Then hippocampal complex
Can then be bound together into an episodic memory
Which area do words activate during encoding?
Left frontal cortex
Which areas do nameable objects activate during encoding?
Left and right frontal cortex
Which area do faces activate during encoding?
Primarily the right frontal cortex
Apperception agnosia
Can say what the object is but can’t replicate (draw)it
Associative agnosia
Can’t identify the object so semantic representation is gone but can draw the item
Long term potentiation
Post synaptic cell becomes depolarised by AMPA receptors and the magnesium is kicked out of the NMDA receptor so the calcium can flow into the cell
Difference between associative and non-associative LTP
If there is long term potentiation in pathway 2 but not pathway 1 that is non-associative
If LTP is in both then it is associative
Long term potentiation
When neuronal connections get stronger
Long term depression
When neuronal connections get weaker
Place cells
Cells in the hippocampus that are involved in spatial recognition
Evidence of place cells
Recorded in rats as different place cells activate when the rat is in a specific area
If NMDA receptors are eliminated in the hippocampus of mice they learn a little in the water maze but are never as good as the control with the NMDA receptors intact
What happens when LTP is induced in mice performing the water maze task?
The excitatory potential is a lot larger and they are faster at escaping the water and learn well where the platform is but when they lack the NMDA receptors they can’t build a stable spatial representation
Frontal cortex
Executive
Motor function
Goal orientated behaviour
Parietal lobe
Somatosensation
Spatial processing and orienting
Decision making
Attention
Temporal lobe
Audition
High level object recognition
Occipital lobe
Vision
The limbic system
the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus
Central occipital lobe
Midline of the back of the brain
Early visual areas (V1,V2,V3)
Left and right occipital lobe
Mid level visual areas (V4,V5)
Cochlear nucleus
Part of the auditory brain stem
First processing stage of auditory processing after the ear
Primary auditory area (A1)
N1 EEG signal shows difference in Dichotic listening task with attention (M20-50 when measure with MEG)
Primary visual cortex (V1) and secondary visual cortex (V2)
Show spiking difference when monkeys attend to the neurons receptive field compare to attend away
V1-V7 visual areas
Show topographic organisation (retinotopy)
What does V4 mid level visual area do?
Form, colour, basic shape processing
Where biased competition model of attention was originally tested and evidence supported the model
Visual pathways
Lateral geniculate body
Dorsal pathway
Ventral pathway
Dorsal pathway (visual pathway)
posterior parietal cortex
spatial/motion processing
areas - V5 and medial superior temporal area
Ventral pathway (visual pathway)
temporal, inferior temporal cortex
form, colour and object processing
areas V4 and unimodal visual association area (TEO)
What area of the brain is involved in motion processing?
Middle temporal area
Which area is involved in colour processing?
Area V4
fMRI experiments show evidence for feature selective attention effects in this area
What is area V4 involved in with attention?
Colour processing (feature based attention)
Object based attention
Evidence for both of these through fMRI
Subcortical attentional network
Pulvinar nucleus (part of the thalamus
Superior colliculus (brain stem part of attentional network)
Both show strong attention dependent activation in speaking and fMRI activity
Cortical (top down) attentional network
These areas are active when subjects attend to a location, even when there is no stimulus present, attentional control areas
Dorsolateral frontal cortex
Inferior parietal lobule (cortex)
Superior temporal sulcus
Posterior cingulate cortex
Medial frontal cortex
Intraparietal sulcus
Frontal eye field
Bottom-up attentional network
Temporo-parietal junction
Ventral frontal cortex (inferior/medial frontal gyrus)
Phonological loop areas
Left inferior frontal gyrus
Supramarginal gyrus
(Areas 44,40)
Visuospatial sketchpad areas
lateral parietal
inferior frontal
occipital areas
Major hippocampal inputs
Entorhinal cortex
(Which also has inputs from perirhinal and parahippocampal cortex
Mamillary bodies
subcortical area with inputs to the
hippocampal formation), often damaged in long term
alcoholics, due to vitamin B1 deficiency
Where pathway areas
Occipitoparietal
Visual areas
To parietal
To parahippocampal
To entorhinal cortex
What pathway areas
Occipitotemporal
Visual areas
To temporal to perirhinal
To entorhinal
Procedural memory area
Basal ganglia
Familiarity area
Entorhinal cortex
Storage area of semantic knowledge
Anterior inferior
temporal: function and meaning of objects
Posterior inferior temporal: fusing of low-level stimulus features into coherent wholes
Amygdala
almond shaped nucleus in the medial temporal lobe involved in emotional processing (fear,
value, anger, …)
Orbitofrontal cortex (OFC)
part of the frontal (ventral
parts) cortex, which is involved in value estimation and comparison. Also involved in (social) decision making and evaluation of social situations. Also involved in processing of angry faces.
areas involved in implicit bias
dorsolateral prefrontal cortex, anterior cingulate cortex, ventrolateral prefrontal cortex
Anterior cingulate cortex
involved in processing of anger (angry faces)
Which areas are active during sadness?
Amygdala, right temporal pole
Which areas process disgust?
Insula cortex, anterior cingulate cortex
medial prefrontal cortex
Involved in self referential processing
also idling, daydreaming, resting state network
resting state network brain areas
dorsal and ventral medial frontal cortex, posterior medial cortex, posterior lateral cortices
orbitofrontal cortex
utilization behaviour, self monitoring
in social environments (see also above in relation to
value estimates, somatic markers, ….)
theory of mind brain area
right temporo-parietal junction (but see
also in relation to bottom up attention)
Dorsolateral prefrontal cortex (dlPFC)
mostly involved in
planning, cognitive control, working memory. As such it contributes to social cognition, but does not have a specialized role
Anterior cingulate cortex (ACC)
error detection, rule selection, social evaluation, reward anticipation, positive self esteem
nucleus accumbens
reward processing
Superior temporal sulcus (STS)
various multimodal functions, attention, tracking of ‘others’ actions/intention.
cerebellum
integrates information about the body and motor commands, and it modifies motor outflow to effect smooth, coordinated movements
thalamus
relay station for almost all sensory information
Patient SM
Amygdala lesions
Patient S.M. had selective deficits to judge whether a fearful expression was displayed.
Patient S.M. had no problem rating any of the other emotional expressions.
Patient S.M. had selective deficits also in generating an image of fearful expressions.
Who studied emotions and claimed certain universal ones?
Ekman and Friesen
Ekman and Friesen: The basic emotions
happiness, sadness, anger, surprise, disgust, and fear
James Lange theory
argues that perception triggers bodily emotional responses, which then trigger the emotional perception
Cannon bard theory
Emotional perception first then emotional experience (facial expressions)
Which task did Damasio develop?
Gambling card task where skin conductance was measured
somatic marker hypothesis
states that emotional information, in the form of physiological arousal, is needed to guide decision making
The cortical (slow/high) road into the amygdala
entails high level processing of information, where most likely conscious awareness of e.g. danger triggers fear and the associated responses
The subcortical low road into amygdala
allows for fast processing of potential danger/benefit, and physical reactions can be triggered before an awareness of and emotion
