Methods in Neuropsychology: Studying Brain Function with Various Mechanical Methods

What is the basic idea behind the Information Processing Paradigm in neuropsychology?

It suggests that any thinking system can be decomposed into basic operations or processes that underlie its operation.

What philosophical position argues that the whole is a product of the sum of its parts?

Reductionism.

What is mental chronometry?

The measurement of mental timing using reaction time.

How does mental chronometry infer sensory and perceptual processes?

By using reaction time in a sensory task to infer the content, duration, and temporal sequencing of these processes.

What does psychophysics study?

The quantification of the relationship between physical stimuli and the sensations and perceptions they generate.

What is the purpose of threshold measurements in psychophysics?

To assess the intensity of the lowest or weakest stimulus that can be detected by an observer.

What are absolute thresholds?

The intensity of a stimulus at which a participant can detect its presence on 50% of the trials.

What are discrimination thresholds?

The minimum level at which a difference between two stimuli can be perceived.

What is single-cell recording?

A technique used to measure the electrical activity of single neurons.

How is the single-cell recording technique performed?

By inserting a thin wire electrode into the brain of an animal to monitor electrical changes in nearby neurons.

What is the primary goal of single-cell recording experiments?

To determine what manipulations produce changes in the firing rate of neurons.

What is electrical brain stimulation?

A method that uses fine wire electrodes to stimulate neurons and help localize brain function.

What is transcranial magnetic stimulation (TMS)?

A noninvasive method used to stimulate small regions of the brain.

What type of stimuli do modern psychophysicists typically use for experiments?

Experimental stimuli that can be objectively measured, such as tones or lights.

What is the definition of a threshold in psychophysics?

The intensity at which a participant can just detect the presence of a stimulus.

What are subliminal stimuli?

Stimuli with intensities below the threshold that are considered not detectable.

What is the role of the device connected to the wire electrode in single-cell recording?

It monitors small changes in current to record electrical activity in neurons.

What is the relationship between reaction time and mental chronometry?

Reaction time is used to measure the timing of mental processes in mental chronometry.

What measurement does the study of psychophysics rely on?

Threshold measurements to assess sensory perception.

What is TMS and how does it work?

Transcranial Magnetic Stimulation (TMS) involves placing a coil near the head to induce small electrical currents in the brain, blocking normal activity in local circuits. Helps localize brain function.

What is the primary use of TMS in neuropsychology?

TMS is considered the best way to simulate a temporary lesion to help localize brain function.

How can TMS be combined with other techniques?

TMS can be used with fMRI to localize brain areas involved in specific perceptual tasks.

What does it indicate if a person cannot perform a task when a brain area is blocked by TMS?

It indicates that the blocked area is involved in the task.

What conditions can TMS be used to treat?

TMS is used to treat chronic depression and evaluate damage from strokes, multiple sclerosis, movement disorders, and other neurological issues.

What is the classic method for studying neuropsychology?

Brain lesions are a classic method, where damaging a specific brain area results in particular behaviors.

What is the concept of dissociation in neuropsychology?

Dissociation occurs when damage to a brain area disrupts one behavior but not another.

What is single dissociation?

Single dissociation is when damage to brain area 'A' disrupts behavior '1' but not behavior '2'.

What is double dissociation?

Double dissociation occurs when damage to brain area 'A' disrupts behavior '1' but not '2', while damage to area 'B' disrupts behavior '2' but not '1'.

What are some structural imaging techniques used in neuropsychology?

Structural imaging techniques include CAT scans and MRIs.

What is a CAT scan and its limitations?

A CAT scan is an advanced x-ray technique that visualizes brain anatomy but exposes the brain to radiation and is not accurate for small structures.

Why has MRI largely replaced CAT scans?

MRI provides better spatial resolution, down to less than a millimeter, and does not expose patients to radiation.

What does MRI rely on to form images?

MRI relies on the abundance of hydrogen molecules in the brain to create images.

What is the significance of hydrogen molecules in MRI?

In their normal state, hydrogen molecules are randomly oriented. In an MRI, they are (1) aligned via magnetic field, (2) forced to oscillate again via radio waves, and (3) when the radio waves are turned off, they relax back to alignment. (4) The relaxing effect produces a magnetic field of its own which is (5) measured and reconstructed into 3D images of the brain's tissue density.

What is the purpose of functional imaging techniques?

Functional imaging techniques like PET and fMRI are used to observe brain activity.

What is the role of intracranial EEG in neuropsychology?

Intracranial EEG (ECoG) records electrical activity from the brain when it is open.

What is MEG and its application?

Magneto-encephalography (MEG) measures magnetic fields produced by neural activity.

What are surface EEG and ERP used for?

Surface EEG and event-related potentials (ERP) are used for time-locked electrical recording of brain activity.

What is multi-modal imaging?

Multi-modal imaging combines different imaging techniques to provide comprehensive insights into brain function.

What is the advantage of modern structural imaging?

Modern structural imaging allows visualization of brain anatomy in living subjects.

What is the significance of advanced computer models in neuropsychology?

Advanced computer models help simulate cognitive and brain functions, aiding in the understanding of brain trauma.

What is the primary function of nuclear magnetic resonance imaging (MRI)?

MRI allows observation of brain structure and activity without invasive procedures.

What happens to hydrogen molecules in a strong magnetic field during an MRI?

They become aligned.

What occurs when hydrogen molecules are exposed to radio waves in an MRI?

The hydrogen molecules are disturbed.

What is produced when hydrogen molecules relax back to their original orientation after radio waves are turned off?

A magnetic field that can be detected by the MRI machine.

What type of images does an MRI produce?

3D images of the brain based on differences in tissue density.

What do functional imaging methods measure in the brain?

Changes in brain metabolism or blood flow during sensory or perceptual tasks.

What is the primary focus of functional imaging methods?

They do not measure the output of neurons but rather changes in systems sensitive to neural processing.

What is the purpose of a radioactive tracer in PET scans?

To measure the decay of tracers during a perceptual task.

How does the PET scanner determine active brain regions?

By measuring increased blood flow and tracer collisions in areas during the task.

What is the control condition in a PET scan?

Participants remain quiet or look at a blank screen to establish a baseline for comparison.

What is a significant drawback of using PET scans?

It uses ionizing radiation, which is not considered safe for women of childbearing age.

What does fMRI exploit to measure brain activity?

The increase in blood flow to active parts of the brain.

How does fMRI differ from structural MRI?

fMRI focuses on the magnetic properties of iron in hemoglobin and measures the ratio of oxygenated to deoxygenated hemoglobin.

What is the Blood Oxygen Level Dependent Response in fMRI?

The measurement of the ratio of oxygenated to deoxygenated hemoglobin in the blood.

What are the advantages of fMRI over PET?

No radiation exposure, continuous testing, lower cost, and greater spatial resolution.

What does EEG measure?

Continuous electrical activity of the brain from the scalp or electrodes inside the brain.

What is an ERP in the context of EEG?

The brain's electrical response to a specific event, such as a stimulus.

How is an ERP obtained from EEG data?

By averaging the EEG signals from multiple presentations of the same event to cancel out noise.

What do the peaks and valleys in an ERP waveform represent?

Neural activity associated with various sensory and perceptual phenomena.

What is MEG and how does it differ from EEG?

Magnetoencephalography measures magnetic fields produced by neuronal activity, providing better localization of signals.

What is a limitation of MEG?

It can only detect sources producing magnetic fields oriented parallel to the skull surface (in sulci), and sources close to the surface of the brain.

What types of brain activity can EEG detect?

Sleep states and sleep conditions, awake brain activity, and seizure disorders like epilepsy.

What is the significance of the amplitude of peaks in ERP waveforms?

It indicates the amount of neural activity dedicated to processing the event.

What is the main advantage of using MEG over EEG?

MEG is not distorted by the brain, skull, and scalp, allowing for better localization of the signal.

What is a common application of EEG?

Detecting epilepsy and diagnosing seizure disorders.