Cognitive research in action Flashcards
introspection
The examination or observation of one’s own mental processes
Capacity limits
Our psychological system is limited in its ability to perform online processing of information
Bit
amount of information we need to make a decision between 2 equally likely alternatives
memory span
the longest list of items that a person can repeat back in the correct order immediately after presentation
Pre-attentive
the unconscious accumulation of information from the environment
Attention
the allocation of limited processing resources
input-output correlation
the measure of transmitted information. a small correlation between input and output suggests that there is a lot of noise in the signal
George Miller
He looked at our cognitive communication system as a system which processes information using input-output correlation. He reasoned that the human channels capacity of the magic number 7+/-2
Code
a system of words, letters or signs used to represent something
Four ways we use code in experiments
- we code participants’ identifiers to keep track of our data and to maintain participants’ anonymity
- we also code our experimental conditions
- we code our data from one type of value to another
- our speech is constructed from code
- the brain uses its own set of neural codes
subtising
using rapid, accurate and confident judgements of numbers. This works for small numbers of items (1 to 4)
How much time do we need to process each item?
250-350ms
Adaptive brain (functions)
Functions to regulate our thoughts, to process sensory information from the environment, to translation important information into something useful for behaviour, to remember previous behaviours, and to promote future behaviour for adaptive survival skills
Donalds Hebb
Worked with many psychologists and neurosurgeons who stimulated the brain and mapped motor pathways during brain surgery
John Hughlings Jackson
made the first brain model organisation
neuron
unit of communication
axon
end of the neuron
network
combination of neurons which could be grouped together as one processing unit
Hierarchy
organisation of brain networks in which higher processes infirm, suppress and inhibit lower ones
EEG
measures electrical activity from the scalp
spectral power
power or energy within a frequency
frequency bands
Delta: 1 - 3 Hz
Theta: 4 - 7 Hz
Alpha: 8 - 12 Hz
Beta: 13 - 30 Hz
tempotal resolution
amount of time needed to revisit and acquire data for the exact same location
spatial resolution
the measure of the smallest object that can be resolved by the sensor
Hebb’s Law
when an axon of cell A if near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth process of metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing cell B, is increased.
Sensors of the Left hemisphere
have odd numbers
Sensors on the right hemisphere
have even numbers
C sensors
represent the motor cortex
Event related potential
The brain’s response to a particular stimulus or motor response (this is averaged across lots of trials of the same type)
Cz sensor
in the middle, along the vertex
how is EEG power estimated
estimated using a mathematical procedure that decomposes an EEG trace into its components
Averaging across trials
forming a wave-form for a patient across many trials
Averaging across patients
forming a wave-form for multiple patients exposed to the same stimulus
complex waveforms
The result of combining the instantaneous amplitudes of two (or more) sine waves
MRI (magnetic resonance imaging)
can be used for measured structure
fMRI (functional magnetic resonance imaging)
used for measuring function
DTI (diffusion tensor imaging)
water diffusion of fibre tracts is used to estimate white matter tract density and integrity
What frequency bands are involved in movement?
alpha and beta (8-30Hz)
Where does movement of the right hand occurs in the brain?
left hemisphere
Where does imagining movement of the right hand occur in the brain?
right hemisphere
Where does movement of the left hand occur in the brain?
the right hemisphere
where does imagining moving the right hand occur in the brain?
the right hemisphere
How to record event-related potentials? (4 steps)
- present a stimulus
- record EEG
- repeat (a lot)
- average recordings after time-locking them to a known stimulus
Callosotomy
the surgical disconnection of the corpus callosum
split-brain
patient’s who have a disconnected brain and separate hemispheres
visual latelarisation
A technique used to deliver stimulus information to each cerebral hemisphere separately
reaction-time
latency to respond
movement time
duration of the movement
spatial coupling
A general concept that can be applied to different existing code constructions
What makes visual lateralisation effective ?
- present the stimulus for a short duration of time (<150ms)
- no eye movements
novel action
something new
well-learnt action
an action which is already coded in the brain and is familiar, almost automatic
automaticity
performance of a skill that has been practiced repeatedly with little or no direct attention
What is the left side of the brain lateralised for?
Local features of display
What is the right side of the brain lateralised for?
more global features
What side is in charge of speech?
The left side
What part of the brain is necessary for spatial coupling?
the corpus callosum
Subcortical
A process that occurs only in one cortex
somatosensory
relating to a sensation that can occur on the body, also refers to the brain’s representation of the body
perceptual illusions
a faulty or distorted perception of something externally represented
representation
an image or likeness of something, as accessed by the brain
cross-modal
use of two different sense modalities. matching (congruent) inputs tend to facilitate performance
corticospinal
An efferent tract
ipsilateral
same side
contralateral
crosses over
bilateral
information is sent to the same side as well as the opposite side
distal
far-away limb
proximal
close-limb
topographical
the arrangement of physical features of an area
homunculus
a representation of a small human being (in the somatosensory cortex)
decussate
cross or intercept to form an X
Wilder Panfield
mapped the functions of various regions of the brain such as the cortical homunculus
Where do projections to the hand cross-over?
The mid-brain
speed-accuracy trade-off
as performance gets faster, accuracy decreases
dual-tasks
performing two tasks simultaneously
low-level constraints
muscle
high-level constraints
cognitive processes
congruent
Matching tasks
incongruent
separate tasks
Difference between congruent and incongruent tasks reaction time
was hypothesised to be due to people conceptually regarding incongruent tasks as two different tasks
perceptual manipulation
connecting the two circles with a line, which now joins the images together.
conceptual manipulation
pre-instruction display either signifying to use ‘both hands’ or the ‘left and right hands’
Congenital mirror movements
a rare, genetic disorder. congenital defects of the motor system can occur, which leads to the existence of extra ipsilateral tracts
bilateral movements
when both limbs are used in unison to contract the muscles
neural compensation
neural activation of additional brain regions or networks that typically are not activated
volition
deciding on and committing to a particular action
plasticity
changes in brain structure
learning
the acquisition of knowledge or skills through eperience, study or by being taught
How much of the corticospinal tracts to the hands and fingers descend ipsilaterally?
20%
