Unit 1A Test: Biological Bases of Behavior

30-35 MCQ, 1 AAQ (STUDY UNIT 0 TERMS too!)

Evolutionary Perspective

A theoretical approach that explains human behavior and mental processes as products of natural selection and adaptation

Twin Studies

A research method used in behavior genetics to compare the traits and behaviors of identical and fraternal twins to measure the relative influences of nature (genetics) and nurture (environment). (Think of triplets)

Heritability

The proportion of variation among individuals in a specific population that can be attributed to genetic differences rather than environmental factors. Percentage of trait that is due to biology

Split-Brain Research and Contralateral Functions

Study of patients whose corpus callosum has been surgically cut (usually to stop severe epileptic seizures). Contralateral functions refer to neurological rule that each cerebral hemisphere processes sensory input from and controls motor commands for the opposite side of the body (left brain to right body, right brain to left body)

Plasticity

Brain's ability to reorganize, change, and adapt its structure and neural connections in response to new experiences, learning, or brain injury (flexibility)

Cerebellum (Brainstem & Hindbrain, 1 of 4)

Location: Back of the brain, underneath the occipital and temporal lobes (the "little brain").

Function: Coordinates voluntary muscle movements, balance, posture, and procedural/nonverbal motor learning.

Medulla (Brainstem & Hindbrain, 2 of 4)

Location: Lower part of the brainstem, directly above the spinal cord.

Function: Controls vital autonomic functions like heartbeat, breathing, and blood pressure

Pons (Brainstem & Hindbrain, 3 of 4)

Location: Above the medulla and below the midbrain in the brainstem.

Function: Helps coordinate movement and controls sleep, arousal, and facial expressions; acts as a bridge carrying information to the cerebellum

Reticular Formation (Brainstem & Hindbrain, 4 of 4)

Location: Inside the brainstem, running through the middle of the medulla and pons up to the thalamus.

Function: Controls arousal, alertness, and sleep-wake cycles (filters incoming sensory stimuli).

Thalamus

Location: Top of the brainstem (center of the brain).

Function: The brain's sensory switchboard or relay station; directs incoming messages for all senses except smell to the higher brain regions.

Amygdala (Limbic System, 1 of 3)

Location: Deep inside the temporal lobes (part of the limbic system, small).

Function: Processes strong emotions, particularly fear, aggression, and survival-related threat responses

Hippocampus (Limbic System, 2 of 3)

Location: In the temporal lobe, adjacent to the amygdala.

Function: Helps process and form explicit/conscious memories for facts and events

 Hypothalamus (Limbic System, 3 of 3)

Location: Just below the thalamus.

Function: Regulates homeostatic drives like hunger, thirst, body temperature, sexual behavior, and controls the endocrine system via the pituitary gland.

Cerebrum

Location: The largest, upper-most part of the brain, split into left and right hemispheres.

Function: Responsible for higher-level thinking, sensory processing, voluntary movement, and conscious action.

Cerebral Cortex

Location: The outer wrinkly surface layer of the cerebrum.

Function: The ultimate control and information-processing center; handles complex cognition, language, and perception.

Corpus Callosum

Location: A wide band of neural fibers connecting the left and right cerebral hemispheres.

Function: Carries messages and allows communication between the left and right hemispheres.

Motor Cortex

Location: Rear of the frontal lobe (along the motor strip).

Function: Controls voluntary muscle movements

Sensory Cortex (Somatosensory Cortex)

Location: Front of the parietal lobe (just behind the motor cortex).

Function: Registers and processes body touch and movement sensations

Pituitary Gland

Location: Base of the brain, right under the hypothalamus.

Function: The "master gland" of the endocrine system; releases hormones that regulate growth and control other glands

Broca’s Area

Location: Left frontal lobe (in most people).

Function: Controls language expression and muscle movements involved in speech production.

Wernicke’s Area

Location: Left temporal lobe (in most people).

Function: Involved in language reception, comprehension, and the meaningful understanding of spoken/written language

Aphasia

Location: Not a physical region itself; it is a neurological condition caused by damage to language areas (usually Broca's or Wernicke's area in the left hemisphere).

Function / Definition: Impairment of language, usually caused by left hemisphere damage either to Broca’s area (impaired speaking) or Wernicke’s area (impaired understanding)

Temporal Lobe

Location: Sides of the brain (roughly above the ears).

Function: Includes areas for auditory processing (hearing), language comprehension, and memory.

Occipital Lobe

Location: Back portion of the brain.

Function: Receives and processes visual information from the eyes

Parietal Lobe

Location: Top-middle section of the brain (behind the frontal lobe).

Function: Receives sensory input for touch and body position (spatial awareness)

Frontal Lobe (includes prefrontal cortex)

Location: Front part of the brain (behind the forehead).

Function: Involved in speaking, muscle movements, abstract thinking, planning, personality, and judgment

Prefrontal Cortex

Location: The very front part of the frontal lobe.

Function: Responsible for executive functions, working memory, decision-making, and social judgment

CT Scan (Brain Imaging, 1 of 3)

What it is: A series of 2D X-ray photographs taken from different angles and combined by a computer to create detailed cross-sectional 3D images of the brain's structure.

When it is used: Used to check for physical brain damage, tumors, strokes, or structural injuries (showing anatomy, not brain activity)

fMRI (Brain Imaging, 2 of 3)

What it is: A technique that measures brain activity and function by tracking changes in blood flow and oxygen levels over time, comparing successive MRI scans.

When it is used: Used to see which specific parts of the brain are active and functioning in real time while a person performs a specific mental task or experiences different stimuli

EEG (Brain Imaging, 3 of 3)

What it is: An amplified recording of the electrical waves of activity sweeping across the brain's surface, measured via small metal electrodes placed on the scalp.

When it is used: Used to study overall brain wave patterns, diagnose sleep disorders (like tracking REM vs. deep sleep), or detect electrical abnormalities like seizures and epilepsy

Central Nervous System (CF + BBB)

Comprises the brain and spinal cord. It acts as the primary control center, processing sensory information, directing motor output, and coordinating higher thought and behavior.

 Cerebrospinal Fluid (CNS, 1 of 2)

A clear, protective fluid surrounding the brain and spinal cord within the ventricles and subarachnoid space. It cushions the CNS against physical shock, delivers nutrients, and helps remove metabolic waste.

Blood-Brain Barrier (CNS, 1 of 2)

A highly selective, tightly-packed membrane of endothelial cells lining brain blood vessels. It blocks harmful toxins, pathogens, and large molecules from entering the brain while allowing essential nutrients, oxygen, and lipid-soluble substances (like alcohol or caffeine) to pass.

Peripheral Nervous System (SNS + ANS)

The network of nerves that connects the central nervous system to the rest of the body (limbs, skin, and internal organs) to relay signals back and forth.

Somatic Nervous System (PNS, 1 of 2)

The division of the PNS that controls voluntary skeletal muscles and transmits conscious sensory information (touch, sight, sound) to the CNS

Autonomic Nervous System (PNS, 2 of 2) (SD + PD)

The division of the PNS that regulates involuntary internal processes, such as heart rate, breathing, digestion, and gland functions, without conscious effort.

Sympathetic Division (ANS, 1 of 2)

The "fight-or-flight" branch of the autonomic nervous system. It arouses the body, mobilizes energy reserves, accelerates the heart rate, and dilates airways during stress or perceived danger.

Parasympathetic Division (ANS, 2 of 2)

The "rest-and-digest" branch of the autonomic nervous system. It calms the body down, slows the heart rate, promotes digestion, and restores routine metabolic homeostasis.

Neurons (NAME ALL PARTS)

Dendrites (receive incoming signals or neurotransmitters from other neurons and send them toward cell body), Cell Body (Soma, central core that houses nucleus and organelles, processes incoming signals), Axon (long, slender fiber that carries the electrical action potential away from cell body toward other cells), Myelin Sheath (Fatty, insulating layer wrapped around axon, formed by Schwann cells, speeds up travel of electrical signals), Nodes of Ranvier (small gaps or interruptions in myelin sheath, allow electrical signal to jump rapidly down axon), Axon terminals (branching ends at far tip of axon, release chemical neurotransmitters across synapse, dont actually touch), Glial cells

Glial cells

Dots on outside, provide physical and metabolic support, insulation, and protection for neurons, remove waste

Spinal cord and reflex arcs (7)

Spinal Cord: A bundle of nerve fibers connecting the brain to the rest of the body, responsible for passing information back and forth and handling automatic responses.

Reflex Arc: A neural pathway, consisting of sensory neurons, interneurons, and motor neurons, that allows a rapid, involuntary response to a stimulus (like pulling your hand from a hot stove) before the signal even reaches the brain

Excitatory and Inhibitory signals (1 of 7)

Excitatory Signals: Neurotransmitter messages that push the receiving neuron closer to firing an action potential (depolarizing the membrane).

Inhibitory Signals: Neurotransmitter messages that push the receiving neuron further away from firing an action potential (hyperpolarizing the membrane)

All or None Principle (2 of 7)

Rule that a neuron either fires a complete action potential at full strength or does not fire at all; there are no half-strength or weak impulses. (Think of toilet example and flushing)

Threshold (3 of 7)

The minimum level of electrical stimulation (depolarization) required at the axon hillock to trigger a neuron's action potential.

Depolarization (4 of 7)

The shift in a neuron's charge when positively charged sodium (\(Na^{+}\)) ions rush into the cell, making the inside less negative and initiating an action potential.

Refractory period (5 of 7)

Brief recovery time immediately following an action potential during which the neuron resets its balance and cannot fire again (or requires a much stronger stimulus).

Resting potential (6 of 7)

The baseline polarized state of a resting neuron (~ 70mV) where the interior is more negative relative to the exterior.

Reuptake (7 of 7)

Process in which excess neurotransmitters left in the synaptic cleft are reabsorbed by the sending (presynaptic) neuron to be recycled

Myelination

Process where myelin sheaths (fatty tissue layers) wrap around the axons of neurons. It insulates the axon and drastically increases the speed of neural impulse transmission.

Neurotransmitters (Dopamine, Serotonin, Norepinephrine, Glutamate, GABA, Endorphins, Substance P, Acetylcholine)

• Dopamine: Controls reward, pleasure, and voluntary movement. Deficits are linked to Parkinson’s disease; excesses are linked to schizophrenia.

• Serotonin: Regulates mood, hunger, sleep, and arousal. Undersupply is strongly linked to clinical depression.

• Norepinephrine: Helps control alertness and arousal. It activates the body's "fight-or-flight" response during stress.

• Glutamate: The primary excitatory neurotransmitter in the brain. It is heavily involved in memory, but too much can cause migraines or seizures.

• GABA (Gamma-Aminobutyric Acid): The primary inhibitory neurotransmitter. It calms central nervous system activity; undersupply is linked to anxiety and insomnia.

• Endorphins: The body's natural painkillers and mood elevators. They are released during exercise, excitement, and pain (causing the "runner's high").

• Substance P: A neurotransmitter responsible for transmitting pain messages from the body to the brain.

• Acetylcholine (ACh): Enables muscle action, learning, and memory. Alzheimer's disease is marked by the deterioration of ACh-producing neurons.

Disruptions to Neural Transmission (Multiple Sclerosis & Myasthenia Gravis)

Multiple Sclerosis (MS): An autoimmune disorder where the immune system destroys the myelin sheath. This slows down or blocks communication between the brain and muscles, leading to loss of motor control.

Myasthenia Gravis: A chronic autoimmune disorder where antibodies destroy acetylcholine receptors at the neuromuscular junction. This causes extreme muscle weakness and fatigue.

Hormones (Adrenaline, leptin, ghrelin, melatonin, and oxytocin)

Chemical messengers produced by the endocrine glands that travel through the bloodstream to coordinate and manage hundreds of bodily functions.

Psychoactive drugs (Stimulants, Depressants, Hallucinogens, Opioids)

• Stimulants: Drugs (e.g., caffeine, nicotine, amphetamines, cocaine) that excite neural activity and speed up body functions.

• Depressants: Drugs (e.g., alcohol, barbiturates, tranquilizers) that calm neural activity and slow down body functions by mimicking GABA.

• Hallucinogens: Drugs (e.g., LSD, marijuana) that distort perceptions and evoke sensory images in the absence of actual sensory input.

• Opioids (Narcotics): Drugs (e.g., heroin, morphine, fentanyl) that depress neural functioning and temporarily lessen pain and anxiety by mimicking endorphins.

Tolerance and addiction

Tolerance: The diminishing effect of a drug with regular use, requiring the user to take larger doses to experience the same effect.

Addiction: A compulsive craving and use of a substance or behavior despite known adverse consequences, often driven by changes in the brain's reward pathway.