Neuroscience and MRI: Key Concepts and Brain Structures

Falling phase of the action potential

The phase in which the membrane potential decreases after reaching its peak, leading to repolarization.

Functional connectivity

The temporal correlation between spatially remote brain regions, indicating how they communicate during rest or tasks.

Functional magnetic resonance imaging (fMRI)

A neuroimaging technique that measures brain activity by detecting changes associated with blood flow.

Grandmother cell

A hypothetical neuron that responds to a highly specific stimulus, such as the image of one's grandmother.

Hyperpolarization

An increase in the membrane potential of a neuron, making it more negative and less likely to fire an action potential.

Inhibitory response

A response that decreases the likelihood of a neuron firing an action potential.

Ions

Atoms or molecules that carry an electric charge, essential for generating action potentials in neurons.

Magnetic resonance imaging (MRI)

A medical imaging technique used to visualize internal structures of the body, particularly the brain.

Mind-body problem

A philosophical issue concerning the relationship between mental states and physical processes in the body.

Modularity

The concept that certain cognitive processes are localized to specific brain regions or modules.

Module

A distinct functional unit of the brain that processes specific types of information.

Nerve fiber

An elongated projection of a neuron that conducts electrical impulses away from the neuron's cell body.

Neurons

The fundamental units of the brain and nervous system, responsible for processing and transmitting information.

Neuropsychology

The study of the relationship between brain function and behavior, often involving assessments of cognitive abilities.

Neurotransmitters

Chemical messengers that transmit signals across synapses between neurons.

Permeability

The ability of a membrane to allow substances to pass through it, crucial for neuronal function.

Phrenology

An outdated theory that claimed personality traits could be determined by the shape of the skull.

Population coding

A neural coding scheme where information is represented by the collective activity of a group of neurons.

Propagated response

The transmission of an action potential along the length of a neuron.

Receptor sites

Specific locations on neurons where neurotransmitters bind to initiate a response.

Refractory period

The period following an action potential during which a neuron is less responsive to stimuli.

Resting potential

The electrical potential difference across the membrane of a resting neuron, typically around -70 mV.

Resting-state MRI

An MRI technique that assesses brain activity by measuring fluctuations in blood flow during rest.

Resting-state functional connectivity

The functional connectivity of brain regions during rest, indicating their baseline communication.

Rising phase of the action potential

The phase in which the membrane potential rapidly increases, leading to the peak of the action potential.

Seed location

A specific brain region used as a reference point in functional connectivity analysis.

Sensory coding

The process by which sensory information is represented in the nervous system.

Sparse coding

A coding strategy where only a small number of neurons are active at any given time to represent information.

Specificity coding

A theory suggesting that individual neurons respond to specific stimuli, encoding particular features.

Spontaneous activity

The baseline level of neuronal firing that occurs in the absence of external stimuli.

Structural connectivity

The physical connections between brain regions, often mapped using diffusion tensor imaging.

Synapse

The junction between two neurons where communication occurs via neurotransmitters.

Task-related fMRI

An fMRI technique that measures brain activity in response to specific tasks or stimuli.

Test location

The specific area of the brain being examined or stimulated during a study.

Wernicke's area

A region in the left temporal lobe associated with language comprehension.

Absorption spectrum

A spectrum showing the wavelengths of light absorbed by a substance, often used in spectroscopy.

Accommodation

The process by which the eye adjusts its focus on near or distant objects.

Amacrine cells

Interneurons in the retina that play a role in visual processing and modulation.

Axial myopia

A type of myopia (nearsightedness) caused by an elongated eyeball.

Bipolar cells

Retinal neurons that transmit signals from photoreceptors to ganglion cells.

Blind spot

The area of the retina where the optic nerve exits, lacking photoreceptors and thus insensitive to light.

Center-surround antagonism

A visual processing mechanism where the response of a neuron is enhanced by stimulation in the center and inhibited by stimulation in the surrounding area.