Cognitive Neuro - Ch 3

Posner task

Task: participants decide if two letters are in the same category

Effect: longer RT for accessing more abstracted representations

Main idea: different response times reflect degrees of processing required

Stroop task

Task: subjects instructed to name the color of a word

Effect: slower to name colors for mismatched colors and words

Main idea: task-irrelevant information interferes with processing

serial processing

sequential, “step-by-step” processing

slow, recognizes bottlenecks

parallel processing

simultaneous processing

faster, requires effective resource allocation

Steinberg memory paradigm

Task: identify if a “probe” letter was part of a set of letters

Effect: RT increases with number of items, no difference for “yes” or “no”

Main idea: comparison process acts in a sequential manner

Word superiority: serial vs. parallel

Task: decide which of two target letters were embedded in a word, nonsense string, or surrounded by Xs

Effect: most accurate when identifying target embedded in a word

Main idea: context affects performance - we activate individual letters and words in parallel

Shephard Mental Rotation

Task: asked whether two (rotated) images match

Effect: RT increases with amount of rotation needed

Main idea: takes time to form a mental image and perform transformations

parametric manipulation

varying the amount of a given process

cognitive subtraction

add or remove a process from the processing stream

Donder’s Method

Task: hit a button in response to a light under various conditions

Effect: RT increases with number of processes executed

Main idea: processes are additive

causal methods

“poking” the brain - interrupting or modifying brain function to see what happens (lesioning, transcranial magnetic stimulation)

correlational methods

“listening” to the brain (fMRI, EEG, single-unit recordings)

stroke

disruption to blood flow in the brain; damage at specific anatomical locations

traumatic brain injury (TBI)

often result from accidents or blows to the head, can cause physical damage and may lead to long-term impairments

neurodegenerative disorders

progressive conditions characterized by gradual loss of neurons and brain function; widespread brain damage

examples: Alzheimer’s, Parkinson’s, Huntington’s

single dissociation

patient group shows impairment on one task, but not another

double dissociation

one patient group shows impairment on one task, second patient group shows impairment on a separate task

provides stronger evidence for selective impairment than single dissociation

deep brain stimulation (DBS)

causal method

implantation of electrodes in the brain and delivering of electrical impulses to modulate neural activity in targeted areas

optogenetics

causal method

uses light to control neurons that have been genetically modified to express light-sensitive ion channels, precise control of neuronal activity

transcranial magnetic stimulation (TMS)

causal method

utilizes magnetic fields to induce electrical currents in specific brain areas, non-invasive modulation of neuronal activity

electrophysiology

correlational method

records electrical activity from individual neurons or groups of neuron at a highly detailed level

electrocorticography (ECoG)

captures electrical activity from surface of the brain using electrodes on the cortex, high spatial and temporal resolution

used to identify epileptic zones, map critical brain functions

electroencephalography (EEG)

measures electrical activity through the scalp, noninvasive

used to diagnose epilepsy, sleep disorders, and brain activity in response to tasks

Event-Related Potentials (ERP)

brain responses tied to specific sensory, cognitive, or motor events; insight into brain function and timing

magnetoencephalography (MEG)

detects magnetic fields produced by neuronal electrical activity, allows for noninvasive study of brain function with good spatial, excellent temporal resolution

computed tomography (CT)

uses X-rays to create detailed images of the brain

used to diagnose injuries, tumors, structural abnormalities

positron emission technology (PET)

visualizes metabolic processes in the brain by detecting radioactive tracers, useful for studying brain function and disorders

magnetic resonance imaging (MRI)

provides high-resolution images of the brain’s structure and anatomy using magnetic fields and radio waves, no exposure to ionizing radiation

diffusion tensor imaging (DTI)

type of MRI that maps diffusion of water molecules in brain tissue, reveals microstructural organization of white matter

functional magnetic resonance imaging (fMRI)

measures brain activity by detecting changes in blood flow, offers insight into brain’s functional areas during tasks or rest

BOLD (blood-oxygen-level-dependent) signal

detected in fMRI, reflects changes in blood oxygenation