Brain Structures, Functions, and Neurotransmitters

Cerebrum

Higher cognitive functions—thinking, memory, language, voluntary movement, and sensory interpretation.

Frontal Lobe

Decision-making, planning, emotions, motor control.

Parietal Lobe

Sensory processing (touch, temperature, pain).

Temporal Lobe

Hearing, language comprehension, memory.

Occipital Lobe

Visual processing.

Cerebellum

Coordination, balance, posture, and fine motor control.

Brainstem

Controls vital life functions like breathing, heart rate, and digestion.

Midbrain

Vision, hearing, motor control.

Pons

Sleep, respiration, facial expressions.

Medulla Oblongata

Heartbeat, blood pressure, reflexes like coughing and sneezing.

Thalamus

Relay station for sensory and motor signals to the cerebral cortex.

Hypothalamus

Regulates hunger, thirst, temperature, and hormones via the pituitary gland.

Amygdala

Processes emotions, especially fear and pleasure.

Hippocampus

Essential for forming new memories and spatial navigation.

Basal Ganglia

Coordinates movement and reward-based learning.

Corpus Callosum

Connects the left and right hemispheres, allowing communication between them.

Pituitary Gland

The 'master gland' that controls hormone release.

Pineal Gland

Regulates sleep-wake cycles via melatonin.

Ventricles & Cerebrospinal Fluid (CSF)

Cushions the brain and removes waste.

Neurotransmitters

Chemical messengers that carry signals across synapses between neurons and other cells.

Glutamate

Primary excitatory neurotransmitter in the brain involved in learning, memory formation, and cognition.

Acetylcholine (ACh)

Vital for muscle contraction in the peripheral nervous system and supports attention, arousal, and memory in the brain.

Gamma-aminobutyric acid (GABA)

The brain's primary inhibitory transmitter that helps regulate anxiety, muscle tone, and sleep.

Glycine

Inhibitory transmitter mostly found in the spinal cord that works with GABA to fine-tune motor and sensory signals.

Dopamine

Controls movement (via basal ganglia), reward, motivation, and learning.

Serotonin (5-HT)

Regulates mood, appetite, sleep, and digestion.

Norepinephrine (Noradrenaline)

Involved in alertness, arousal, and fight-or-flight responses.

Epinephrine (Adrenaline)

More of a hormone than a neurotransmitter in the brain involved in the acute stress response.

Endorphins and Enkephalins

The body's natural painkillers that promote feelings of euphoria and well-being (e.g., "runner's high").

Substance P

Transmits pain signals in the spinal cord and brain and also plays roles in inflammation and stress perception.

Histamine

Plays a role in arousal, sleep regulation, and immune responses; involved in wakefulness and appetite control in the brain.

Nitric Oxide (NO)

A gas that diffuses across cell membranes and modulates blood flow, learning, and memory—not stored in vesicles like traditional neurotransmitters.

Prefrontal Cortex

Handles decision-making, impulse control, and planning; it's the CEO of your brain.

Nucleus Accumbens

Central to reward, motivation, and pleasure; it lights up when you experience something enjoyable.

Ghrelin

A hormone that stimulates hunger and interacts with dopamine to enhance food-related reward signals.

Sensory Neuron

Transmits sensory information (like touch or pain) from the body to the brain.

Synapse

The tiny gap between neurons where neurotransmitters pass messages.

Myelin Sheath

A fatty layer that insulates axons, speeding up electrical signals in the nervous system.

Positive Incentive Theory

Suggests we're motivated to engage in behaviors (like eating or drug use) because of the anticipated pleasure or reward.

Conditioned Tolerance

When the body learns to anticipate a drug's effects in a specific environment, reducing its impact.

Conditioned Drug Tolerance

A more specific form of conditioned tolerance—tolerance develops in response to environmental cues associated with drug use.

Physical Dependence

When the body adapts to a drug and needs it to function normally.

Withdrawal Syndrome

The unpleasant physical and psychological symptoms that occur when a dependent person stops using a substance.

Addiction

A chronic condition marked by compulsive drug use despite harmful consequences, often involving changes in the brain's reward system.

Methadone

A synthetic opioid used to treat opioid addiction; it reduces withdrawal symptoms and cravings without producing a high.

Ketogenesis

A metabolic process where the body produces ketone bodies from fat, often triggered by low carbohydrate intake or fasting.

Hypoglycemia

Low blood sugar, which can cause shakiness, confusion, and even unconsciousness if severe.

Autonomic Nervous System

Controls involuntary functions like heart rate, digestion, and breathing; has two branches: Sympathetic (activates "fight or flight") and Parasympathetic (promotes "rest and digest").

Sagittal Plane

A vertical anatomical plane that divides the body into left and right sections.

Cortisol

A stress hormone that can influence appetite and metabolism.

Leptin

A hormone that signals satiety; imbalance may lead to overeating and obesity.

Carbohydrates

The body's quick energy source, especially when blood sugar is low.

Leptin Imbalance

May cause a person to eat without feeling full.

Insulin

A hormone that lowers blood sugar by helping cells absorb glucose.

Fats (Lipids)

A long-lasting energy source, especially during performance.

Broca's Area

Controls speech production.

Spinal Cord

Transmits reflexes and neural signals between the brain and body.

Adrenaline

A neurotransmitter that triggers the fight-or-flight response.

Absorptive Phase

The metabolic phase when nutrients are absorbed and stored.

Serotonin

A neurotransmitter linked to mood and appetite regulation.

Sympathetic Nervous System

Prepares the body for 'fight or flight' in response to stressful or threatening situations. It increases heart rate, enhances alertness, and mobilizes energy.

Environmental Cues

Stimuli in a specific environment—like places, people, or objects—that can trigger memories or cravings, especially in individuals recovering from substance use.

Ventromedial Hypothalamus

A specific region of the hypothalamus that helps signal satiety or the feeling of fullness. Damage to this area can cause a person to overeat, as the brain no longer registers when the body has had enough food.

Mesocorticolimbic Pathway

A major dopamine pathway in the brain that connects the midbrain (specifically the ventral tegmental area) to both the limbic system and the prefrontal cortex. It plays a key role in motivation, reward, pleasure, and reinforcement learning.

Norepinephrine

Hormone and neurotransmitter involved in the body's fight-or-flight response.

Insulin and Glucagon

Insulin is a hormone that lowers blood sugar by helping cells absorb glucose from the bloodstream, while Glucagon is a hormone that raises blood sugar levels by signaling the liver to release stored glucose.