C BBB - Chapter 3: The Electrophysiological Brain

Mental representation

The sense in which properties of the outside world are copied or simulated by cognitions.

Neural representation

The way in which properties of the outside world manifest themselves in neural signals.

Grandmother cells

A hypothetical neuron that represents a highly specific concept or object and activates only when that entity is recognized.

Exogenous

ERP components related to sensory stimuli.

Endogenous

ERP components related to the task being performed.

Magnetoencephalography (MEG)

A non-invasive method for recording magnetic fields generated by the brain at the scalp.

Representations

Properties of the world that are manifested in cognitive systems and neural systems.

Single-cell recordings (or single-unit recordings)

Measure the responsiveness of a neuron to a given stimulus in terms of action potentials per second.

Electroencephalography (EEG)

Measurements of electrical signals generated by the brain through electrodes placed on the scalp.

Event-related potential (ERP)

The average change in voltage at the scalp linked to the timing of specific cognitive events.

Reaction time / response time

The time between the onset of a stimulus and the production of a behavioural response.

Multi-cell recordings (or multi-unit recordings)

The electrical activity of many individually recorded neurons measured at one or more electrodes.

Local representation

A representation in which all information about a stimulus is carried by a single neuron.

Fully distributed representation

A representation in which all information about a stimulus is distributed across all neurons in a population.

Sparse distributed representation

A distributed representation in which only a small proportion of neurons carry information about a stimulus.

Rate coding

A coding scheme in which information is represented by the number of action potentials per second.

Temporal coding

A coding scheme in which information is represented by the timing or synchrony of neuronal firing.

Dipole

A pair of positive and negative electrical charges separated by a small distance.

Mental chronometry

The study of the time course of information processing in the nervous system.

Additive factors method

A method for dividing reaction times into different processing stages.

N170

An ERP component occurring around 170 ms that is associated with processing facial structure.

Associative priming

Faster responses to a stimulus when it is preceded by a previously associated stimulus.

Inverse problem

The difficulty of determining the neural source of electrical activity from measurements taken at the scalp.

Dipole modeling

A method for solving the inverse problem by assuming a certain number of neural dipoles contribute to the recorded signal.

All-or-none principle

The principle that a neuron either generates a full action potential or none at all.

Threshold

The minimum level of electrical input required to trigger an action potential.

Neural coding

The way information is represented and transmitted by neurons.

Concept cell

A neuron that responds to a specific concept regardless of how it is presented.

Electrophysiology

The study of the electrical activity of neurons and the nervous system.

Spike rate

The number of action potentials generated by a neuron per second.

Population coding

The representation of information through the combined activity of multiple neurons.

Scalp recording

The measurement of electrical activity using electrodes placed on the scalp.

Latency

The time between the onset of a stimulus and the occurrence of a neural response.

ERP component

A characteristic positive or negative deflection in an ERP waveform associated with a cognitive process.

Face inversion effect

The finding that faces are processed less efficiently when presented upside down.

Neural synchrony

The simultaneous firing of multiple neurons that may contribute to temporal coding.

Sternberg task (Encoding stage)

The first stage in which the probe stimulus is identified.

Sternberg task (Comparison stage)

The second stage in which the probe is compared with items held in memory.

Sternberg task (Decision stage)

The third stage in which a response is selected.

Sternberg task (Response stage)

The fourth stage in which the behavioural response is executed.

Event-related magnetic field (ERMF)

The magnetic equivalent of an ERP measured using MEG.

Source localization

Methods used to estimate the neural generators responsible for EEG, ERP or MEG signals.

Neural plausibility

The extent to which a proposed coding scheme resembles the way real neurons operate.

Concept neuron

A neuron that responds selectively to a specific concept, person or object across different sensory modalities.

Sternberg task

A memory-scanning task used to investigate stages of information processing and mental chronometry.

Serial processing

Information processing in which stages occur one after another.

Parallel processing

Information processing in which multiple operations occur simultaneously.

Component process

An individual stage of information processing identified through reaction-time experiments.