Neuroimaging and Cognitive Neuroscience Methods

Vocabulary practice flashcards covering brain lesions, neuroimaging modalities (sMRI, dMRI, fMRI), electrophysiological methods (EEG, ERPs, ECoG), and neuroimaging analysis concepts.

Single-Dissociation

When a lesion in a specific brain region impairs Process A but leaves Process B intact, suggesting localization of function.

Double-Dissociation

When lesion in Region 1 impairs Process A but not B, and lesion in Region 2 impairs Process B but not A; provides strong evidence for independent, specialized brain structures.

Virtual Lesion

A temporary, reversible disruption of neural activity in a specific cortical region created non-invasively using Transcranial Magnetic Stimulation (TMS).

Transcranial Magnetic Stimulation (TMS)

A non-invasive technique using magnetic pulses to temporarily disrupt or stimulate local cortical function; high temporal resolution, limited to superficial cortical structures.

Structural MRI (sMRI)

An MRI technique used to measure static anatomical brain features, such as gray matter volume, tissue density, and cortical thickness.

Cortical Thickness

A structural MRI metric measuring the thickness of the cerebral cortex layers; useful for studying neurodevelopmental or psychiatric conditions like bipolar disorder.

Diffusion MRI (dMRI)

An MRI technique measuring the directional diffusion of water molecules along axons to map white matter pathways and anatomical connectivity.

Isotropic Diffusion

Water molecule movement that occurs equally in all directions, typically seen in cerebrospinal fluid or unconstrained environments.

Anisotropic Diffusion

Water molecule movement restricted to specific directions, characteristic of water diffusing along intact, highly structured axonal bundles.

Functional MRI (fMRI)

A neuroimaging method measuring brain activity by detecting local hemodynamic changes and blood-oxygenation levels over time.

Blood Oxygen Level-Dependent (BOLD) Signal

The primary signal measured in fMRI, reflecting changes in the ratio of oxygenated to deoxygenated hemoglobin in response to neural activity.

Repetition Time (TR)

The time interval between successive radiofrequency pulses applied to a volume during an fMRI acquisition sequence; defines temporal sampling rate.

Spatial Resolution

The ability of an imaging method to discriminate between two adjacent physical locations in space (high in fMRI/sMRI, poor in EEG).

Temporal Resolution

The ability of a recording technique to resolve rapid changes in neural activity over time (high in EEG/ERP, poor in fMRI).

Block Design

An fMRI task paradigm grouping identical trials into extended blocks; offers high statistical power for detecting overall brain activation levels.

Event-Related Design

An fMRI task paradigm presenting trials in randomized or interleaved order; best for distinguishing specific neural representations and single-trial dynamics.

fMRI Activation

A measure of the overall level or intensity of neural engagement in a specific region during a cognitive task.

fMRI Representation

The pattern or similarity of multi-voxel neural activity within a region, indicating how specific cognitive contents or stimuli are encoded.

Functional Connectivity

Statistical correlation or synchronization of fMRI time-series signals between distant brain regions over time, without implying direct physical connections.

Seed Region Approach

A method for assessing functional connectivity by selecting a specific region of interest ("seed") and calculating time-series correlations with all other brain regions.

Resting-State fMRI

An fMRI recording taken while the participant is awake but performing no active task, used to measure intrinsic baseline functional networks.

Task-Induced fMRI

An fMRI recording acquired while participants perform specific cognitive tasks to identify stimulus- or state-driven neural responses.

Electroencephalography (EEG)

A non-invasive technique measuring spontaneous electrical activity generated by synchronized population firing of neurons near the scalp.

Event-Related Potentials (ERPs)

Averaged EEG epoch waveforms locked to specific events, cancelling out background noise to boost the time-locked signal-to-noise ratio.

Electrocorticography (ECoG)

An invasive electrophysiological technique placing electrode grids directly onto the exposed cortical surface; offers high spatial and temporal resolution.

Psychophysiological Interaction (PPI)

An fMRI analysis technique assessing how functional connectivity between two brain regions changes as a direct function of a psychological task condition.