introduction to cognitive psychology (week 2) Flashcards
what is the difference between bottom-up and top-down processing?
bottom-up describes when all processing is directly triggered by the stimulus, whereas top-down describes when processing is caused by the individual person due to prior knowledge.
what are “grandmother” cells?
neurons that fire to particular concepts
what is the information processing approach?
humans as “stimulus response machines”, assumes serial (one step at a time) and bottom-up processing
what is the difference between rate and temporal codes?
rate coding describes the idea that the speed at which a neuron fires is dependent on the information a neuron represents, whereas, temporal coding describes the idea that the representation of information is due to the synchrony of neurons firing
what is experimental cognitive psychology?
where experiments are done in labs using experimental manipulation, then output/behavior is measured
what is cognitive neuropsychology?
when the cognition in patients with brain injuries is studies in order to find out which functions are impaired and which ones are preserved when a given region is brain damaged
what is cognitive neuroscience?
relating brain structure to cognitive processes by recording brain activity whilst participants perform cognitive tasks
Where is the frontal lobe located?
directly behind the forehead, at the front of the brain
what are single-cell recordings (electrophysiology)?
the measurement of electrical activity within brain cells
EEG (electroencephalography)
when a series of electrodes are placed on the scalp of an individual to record the electrical activity generated from a large number of neurons firing at the same time - this is non-invasive and allows neural activity to be measured in essentially real-time
what are event-related potentials (ERPs)?
these measure EEG response to the same stimulus/task over and over - the average waveform generates an “event-related potential”
what are the advantages and limitations of EEGs/ERPs?
good temporal resolution (milliseconds), portable and relatively cheap, however, poor spatial resolution (centimeters)
what are MRIs (magnetic resonance imaging)?
when we put someone in a strong magnetic field (0.5-7 Tesla) - the protons in our brain spin and line up with the direction of the magnetic field and we can measure these changes
what are structural MRIs (diffusion tensor imaging)?
these work by measuring how water diffuses across white matter fibers (bundles of axons), which allows us to study how cognition is supported by connections within the brain
what are functional MRIs?
these measure the BOLD (blood oxygenation level dependent signal) response of neurons - active neurons need oxygen so our brain supply oxygen to active areas which cause an overshoot in oxygenated blood - oxygenated blood causes less magnetic field disturbance than deoxygenated blood, so active brain regions have a higher signal
where is the parietal lobe located?
near the back and top of the head
where is the temporal lobe located?
behind the ears and below the parietal lobe
where is the occipital lobe located
at the very back of the skull
where is the cerebellum located?
just above and behind where the spinal cord connects to the brain
how many neurons are in the human brain?
80 billion
what is subtraction logic?
when we design experiments to make sure we isolate the cognitive process we are interested in
what are the advantages and limitations of fMRI?
very good spatial resolution (millimeters) however poor temporal resolutions (seconds), and it is not a measure of the neurons themselves therefore requiring indirect inference that neurons are firing due to the use of oxygen
what is TMS (transcranial magnetic stimulation)?
short magnetic pulses that briefly affect electrical activity in a localised patch of brain tissue under the coil - this is typically applied before or after a cognitive task and can have either positive or negative effects on said task performance - this demonstrates whether or not an area is important for the task
what are the advantages and limitations of brain stimulation?
it is mostly non-invasive, however it has a potential risk to those with a history of epilepsy and the effects produced are often weak as the stimulation is too
