Neuroscience: Neurons, Signals, and Brain Functions

Neuron

A specialized cell that transmits nerve impulses throughout the body.

Dendrites

Extensions of a neuron that receive signals from other neurons.

Cell Body

The part of a neuron that contains the nucleus and maintains the cell's health.

Axon

A long projection that transmits electrical impulses away from the cell body.

Myelin Sheath

A fatty layer that insulates axons and speeds up signal transmission.

Axon Terminals

The endings of an axon that release neurotransmitters into the synapse.

Resting Membrane Potential

The electrical charge difference across a neuron's membrane when it is not firing.

Semipermeable

A property of membranes that allows certain substances to pass while blocking others.

Action Potential

A rapid change in electrical charge that travels down an axon when a neuron fires.

Excitatory Signals

Neural signals that increase the likelihood of a neuron firing.

Inhibitory Signals

Neural signals that decrease the likelihood of a neuron firing.

All-or-None Principle

The principle stating that a neuron either fires completely or not at all.

Chemical Signals

Neurotransmitters that transmit signals between neurons across synapses.

Electrical Signals

Signals that travel within a neuron.

Neurotransmitters

Chemicals that transmit signals across a synapse from one neuron to another.

Dopamine

A neurotransmitter associated with pleasure, reward, and movement.

Serotonin

A neurotransmitter that regulates mood, appetite, and sleep.

GABA

The main inhibitory neurotransmitter that produces a calming effect.

Glutamate

The primary excitatory neurotransmitter involved in learning and memory.

Acetylcholine

A neurotransmitter that plays a key role in muscle movement and memory.

Norepinephrine

A neurotransmitter involved in alertness and arousal.

Presynaptic Neuron

The neuron that sends the signal in a synaptic transmission.

Postsynaptic Neuron

The neuron that receives the signal in a synaptic transmission.

Reuptake

The process by which neurotransmitters are reabsorbed into the presynaptic neuron.

Psychoactive Drug

A substance that alters mood, perception, or behavior.

Agonist Drug

A substance that mimics or enhances the effect of a neurotransmitter.

Antagonist Drug

A substance that blocks or reduces the effect of a neurotransmitter.

Central Nervous System (CNS)

The part of the nervous system consisting of the brain and spinal cord.

Peripheral Nervous System (PNS)

The part of the nervous system that includes all nerves outside the CNS.

Somatic Nervous System

The division of the PNS responsible for voluntary muscle movements.

Autonomic Nervous System

The division of the PNS that controls involuntary bodily functions.

Sympathetic Nervous System

The part of the autonomic nervous system that triggers the fight or flight response.

Parasympathetic Nervous System

The part of the autonomic nervous system that promotes rest and digestion.

EEG

A technique that measures the electrical activity of the brain.

fMRI

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

TMS

A non-invasive procedure that uses magnetic fields to stimulate nerve cells in the brain.

PET Scan

A brain imaging technique that uses radioactive tracers to visualize brain activity.

Brainstem

The part of the brain that controls basic survival functions such as breathing.

Cerebellum

The part of the brain that coordinates balance, movement, and fine motor skills.

Frontal Lobe

The brain region responsible for planning, decision-making, and voluntary movement.

Parietal Lobe

The brain region that processes touch and spatial awareness.

Temporal Lobe

The brain region involved in hearing and language processing.

Occipital Lobe

The brain region responsible for visual processing.

Corpus Callosum

A band of fibers that connects the left and right hemispheres of the brain.

Thalamus

A subcortical structure that acts as a sensory relay station.

Hypothalamus

A subcortical structure that regulates hormones and homeostasis.

Amygdala

A subcortical structure involved in emotion regulation.

Hippocampus

A subcortical structure critical for memory formation.

Split-Brain Patients

Individuals whose corpus callosum has been severed, leading to communication issues between hemispheres.

Attention

The cognitive process of focusing mental resources on specific stimuli.

Automatic Attention

Attention that occurs without conscious effort.

Controlled Attention

Attention that requires conscious effort and focus.

Selective Attention

The ability to focus on one stimulus while ignoring others.

Cocktail Party Effect

The phenomenon of hearing one's name in a noisy environment.

Sensation

The process of detecting physical stimuli.

Perception

The process of interpreting sensory information.

Transduction

The conversion of physical energy into neural signals.

Sensory Adaptation

The decrease in sensitivity to a constant stimulus over time.

Gestalt Principles

Rules that describe how we organize visual information into meaningful wholes.

Monocular Depth Cues

Depth cues that can be perceived with one eye.

Binocular Depth Cues

Depth cues that require both eyes for perception.

Brain Plasticity

The brain's ability to change and adapt as a result of experience.

Synaptic Pruning

The process of eliminating unused neural connections.

Critical Periods

Specific windows of time when certain experiences are essential for development.

Infant Reflexes

Automatic responses that infants exhibit, such as sucking.

Harlow Monkey Study

Research demonstrating the importance of comfort in attachment over food.

Strange Situation Test

An assessment that evaluates infant attachment styles.

Secure Attachment

A style characterized by distress when separated and joy when reunited.

Avoidant Attachment

A style marked by little emotional response to separation or reunion.

Ambivalent Attachment

A style characterized by anxiety during separation and difficulty being comforted.

Cognitive Changes in Aging

Declines in fluid intelligence and memory, while crystallized intelligence remains stable.

Nonassociative Learning

Learning that involves a single stimulus.

Habituation

A decrease in response to a repeated stimulus.

Dishabituation

The return of a response following a change in stimulus.

Sensitization

An increased response to a stimulus after exposure.

Associative Learning

Learning that occurs when two stimuli are linked.

Classical Conditioning

A learning process that pairs a neutral stimulus with an unconditioned stimulus.

Operant Conditioning

A learning process that involves consequences for behavior.

Positive Reinforcement

Adding a stimulus to increase a desired behavior.

Negative Reinforcement

Removing an aversive stimulus to increase a desired behavior.

Positive Punishment

Adding an aversive stimulus to decrease an undesired behavior.

Negative Punishment

Removing a pleasant stimulus to decrease an undesired behavior.