Unit 1: Brain, Neurotransmitter

Peripheral Nervous System (PNS)

Connects the central nervous system to the rest of the body.

Somatic Nervous System

Division of the PNS that enables voluntary control over muscles.

Autonomic Nervous System

Division of the PNS that regulates involuntary bodily functions.

Sympathetic Nervous System

Division of the autonomic nervous system that activates the body (fight/flight/freeze response, increases heart rate, decreases digestion).

Parasympathetic Nervous System

Division of the autonomic nervous system that calms the body and brings it back to a resting state; promotes digestion.

Homeostasis

The state of steady internal physical and chemical conditions maintained by living systems; brings the body back to a resting state.

Central Nervous System (CNS)

Composed of the brain and spinal cord.

Sensory Neurons (Afferent)

Neurons that carry incoming information from the sensory receptors (body) to the brain and spinal cord.

Motor Neurons (Efferent)

Neurons that carry outgoing information from the brain and spinal cord out to the body/muscles.

Interneurons

Neurons within the brain and spinal cord that communicate internally and process information between the sensory inputs and motor outputs.

Reflex

Automatic, involuntary, and rapid responses to stimuli processed through the spinal cord.

Agonists

Molecules that increase neurotransmitter action/amount, often by decreasing or stopping reuptake.

Antagonists

Molecules that decrease neurotransmitter action/amount, often by increasing reuptake.

Selective Serotonin Reuptake Inhibitors (SSRIs)

Antidepressants that stop the reuptake of serotonin, increasing serotonin levels in the synapse.

Cortisol

A hormone released in response to stress; known as the stress hormone.

Pituitary Gland & Hypothalamus

The "master gland" connected to the hypothalamus that releases Human Growth Hormone (HGH) and triggers hormone production in other glands.

Oxytocin

A hormone associated with social bonding, trust, and empathy ("bonding/love hormone").

Acetylcholine (ACh)

Involved in thought, learning, memory, and muscle action. Deficits are linked to Alzheimer's disease and Myasthenia Gravis.

Myasthenia Gravis

An autoimmune disorder characterized by reduced ACh, leading to muscle weakness and fatigue.

Dopamine

Influences movement, learning, attention, emotion, and reward mechanisms. Deficits are linked to Parkinson's disease; excesses are linked to Schizophrenia.

Serotonin

Regulates mood, hunger, sleep, and arousal. Low levels are linked to depression, anger, and anxiety/OCD.

Norepinephrine

Helps control alertness and arousal; involved in the fight-or-flight response. Deficits can depress mood.

GABA (Gamma-Aminobutyric Acid)

Primary inhibitory neurotransmitter that calms nerve activity ("calms you down"); low levels are linked to anxiety.

Glutamate

Primary excitatory neurotransmitter involved in memory and learning; excess can cause overstimulation/seizures.

Endorphins

Neurotransmitters involved in pain control and pleasure ("euphoria"); released during exercise and excitement to reduce pain.

Substance P

Neurotransmitter responsible for transmitting pain signals to the brain.

Lesion

Tiny areas of brain tissue destruction, studied to understand brain function.

Electroencephalogram (EEG)

Measures electrical activity/signals and waves across the brain surface.

Magnetoencephalography (MEG)

Records magnetic fields produced by the brain's electrical currents.

Computed Tomography (CT)

Uses multiple X-ray images taken from different angles to create cross-sectional slice images.

Magnetic Resonance Imaging (MRI)

Uses magnetic fields and radio waves to produce detailed maps of brain structure.

Functional MRI (fMRI)

Measures brain activity by detecting changes in blood flow while comparing continuous scans.

Prosopagnosia

A neurological condition characterized by the inability to recognize faces ("facial blindness").

Medulla

Located in the brainstem/hindbrain; controls heartbeat and breathing.

Thalamus

The brain's sensory switchboard located on top of the brainstem; routes sensory information to higher brain regions for all senses except smell.

Reticular Formation (RAS)

Nerve network in the brainstem that plays an important role in controlling arousal, alertness, and sleep-wake cycles.

Cerebellum

Coordinates voluntary movement, balance, and fine motor control; processes implicit memories (procedural learning).

Basal Ganglia

Group of structures that control voluntary motor movements, procedural learning, and habit formation.

Pons

Helps coordinate involuntary muscle movements, sleep, and motor control.

Limbic System

Neural system located below the cerebral hemispheres; associated with emotions and drives.

Amygdala

Structure in the limbic system linked to emotion, specifically anger and fear.

Hypothalamus

Directs maintenance activities (eating, drinking, body temperature, sexual arousal) and helps govern the endocrine system via the pituitary gland.

Hippocampus

Structure in the limbic system that encodes and processes explicit memories for storage in the cerebral cortex.

Cerebral Cortex

The outer layer of neural tissue that enables higher-level thinking and information processing.

Association Areas

Regions of the cerebral cortex not involved in primary motor or sensory functions, but rather in higher mental processes like learning, remembering, thinking, and speaking.

Corpus Callosum

The large band of neural fibers connecting the two brain hemispheres, allowing them to communicate.

Frontal Lobe

Involved in working memory, personality, judgment, decision-making, and emotional control.

Motor Cortex

Controls voluntary movements; the top controls lower body parts (toes) and the bottom controls upper body parts (head).

Phineas Gage

Famous case study of a railroad worker who survived an iron rod driven through his frontal lobe, leading to dramatic changes in personality and emotional regulation.

Broca's Area

Located in the left frontal hemisphere; controls language expression and muscle movements involved in speech.

Contralateral Hemispheric Organization

The principle that each hemisphere of the brain controls and receives sensory input from the opposite side of the body (e.g., the right hemisphere controls the left side/eye).

Aphasia

Impairment of language, usually caused by left-hemisphere damage, leading to trouble speaking clearly or understanding speech