Ch. 1 Flashcards
the principle of cost control:
costs would be minimised if the brain consisted of limited, short-distance connections
the principle of efficiency:
efficiency in terms of the ability to integrate information across the brain through numerous long distance connections
Single-unit recording
is a fine-grain technique permitting the study of single neurons. A micro-electrode is inserted into the brain to record extracellular potentials. Information about neuronal activity can be obtained over a wide range of time periods, however, it only provides information at the single-neuron level.
Event-related potentials (ERPs)
An electroencephalogram (EEG) is based on recordings of brain activity measured at the scalp, but a key problem is that background activity may obscure the impact of stimulus processing – a solution is to present the stimulus several times to produce event-related potentials (ERPs):
ERPs have limited spatial resolution but high temporal resolution, providing a continuous measure of the time course of the response.
ERPs have been used to investigate the time course of processing.
ERPs are mainly of value when the stimuli are simple and the task involves basic processes occurring at a certain time after stimulus onset.
Positron emission tomography (PET)
Positron emission tomography (PET) is based on detection of positrons from radioactively labelled water injected into the body. Increased blood flow to active areas of the brain is indicated by increased positron detection:
PET has reasonable spatial resolution (5–10mm) but very poor temporal resolution (30–60s).
PET provides only an indirect measure of neural activity and is an invasive technique.
Magnetic resonance imaging (MRI
In magnetic resonance imaging (MRI), radio waves are used to excite atoms in the brain, which produces magnetic changes detectable by a large magnet surrounding the body:
MRI produces a precise 3-D picture.
MRI only tells us about structure, not function.
fMRI has a better temporal resolution (2–3s) and spatial resolution (1mm) than PET.
fMRI
Functional MRI (fMRI) measures the BOLD (blood oxygen level-dependent contrast) signal. This is a distortion in the local magnetic field when oxyhaemoglobin is converted to deoxyhaemoglobin when neurons consume oxygen. Event-related fMRI (efMRI) allows comparison of brain activity across different cognitive events, for example during learning and retrieval in a recognition memory task. fMRI is more useful than PET as it provides more precise spatial information and shows changes over shorter periods of time.
Magneto-encephalography (MEG)
Magneto-encephalography (MEG) uses a super-conducting quantum interference device (SQUID) to measure magnetic fields produced by electrical brain activity:
Transcranial magnetic stimulation (TMS)
In transcranial magnetic stimulation (TMS), a coil is placed close to the participant’s head and a brief but large pulse of current is run through it in a short time. In practice several pulses are usually administered (repetitive transcranial magnetic stimulation (rTMS)). Each magnetic pulse creates a short-lived magnetic field that inhibits processing activity in the area:
Computational cognitive science is an approach to understanding human cognition that uses…
computational models. Computational modelling involves programming computers to mimic aspects of human cognitive functioning. Artificial intelligence, in contrast, involves constructing computer systems that produce intelligent outcomes, but the processes may bear little resemblance to those used by humans.
Cognitive neuropsychology is concerned with….
the patterns of cognitive performance shown by patients with brain damage.
bottom-up processing.
Processing directly affected by the input
Serial processing
is when only one process occurs at a given time.
Top-down processing occurs when…
processing is influenced by the individual’s knowledge and expectations.
Cognitive neuroscience involves study of…
the brain as well as behaviour.
