Unit 1: Biological Bases of Behavior

Comprehensive vocabulary flashcards covering the biological bases of behavior, including nervous system divisions, neurons, action potentials, neurotransmitters, brain structures, and neuroimaging methods.

Nature vs. Nurture

The debate over whether human behavior, mental health, and personality are driven primarily by genetics or by environmental stimuli.

Genetic Predisposition

An inherited increased likelihood or susceptibility to developing a specific behavior, personality trait, or psychological disorder.

Evolutionary Perspective

An approach that views human thoughts, emotions, and behaviors as evolved adaptations shaped by natural selection over millions of years to solve ancestral survival and reproduction problems.

Twin Studies

Research methods that compare identical and fraternal twins to measure how genetics versus environment shapes human behavior.

Central Nervous System (CNS)

The primary control center of the body, consisting of the brain and the spinal cord.

Peripheral Nervous System (PNS)

All the nerves that branch out from the brain and spinal cord to connect the central nervous system to the rest of the body; essential for communication.

Somatic Nervous System

A division of the peripheral nervous system that manages voluntary movements and relays sensory information to the central nervous system.

Autonomic Nervous System

The part of the peripheral nervous system that unconsciously regulates involuntary bodily functions, such as heartbeat, digestion, and breathing.

Sympathetic Nervous System

The division of the autonomic nervous system that mobilizes the fight-or-flight response, preparing the body for action, stress, or danger.

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body down after a stressful event to conserve energy.

Glial Cells

Cells in the central and peripheral nervous systems that provide physical support, metabolic maintenance, and protection for neurons.

Neurons

Nerve cells responsible for receiving, processing, and transmitting electrical and chemical signals.

Reflex Arc

A neural pathway that controls an involuntary, rapid response to a stimulus without requiring initial processing from the conscious brain.

Sensory Neurons

Specialized nerve cells in the peripheral nervous system that convert physical and chemical stimuli from the environment into electrical impulses.

Motor Neurons

Nerve cells in the central nervous system that transmit output signals to muscles, glands, and organs, directly controlling voluntary and involuntary movements.

Interneurons

Specialized nerve cells that connect sensory and motor neurons within neural pathways.

Neural Transmission

The electrochemical process by which nerve cells communicate with each other, or with muscles and glands.

All-or-Nothing Principle

The rule stating that an individual neuron or muscle fiber will either fire a full-strength action potential or not fire at all.

Action Potential

A brief electrical impulse that travels down a neuron's axon, allowing nerve cells to communicate with one another.

Depolarization

The process by which a neuron's internal electrical charge becomes less negative (moving toward or past zero) because positively charged sodium ions ($\text{Na}^+$) rush into the cell.

Refractory Period

The delay in a person's reaction time to a second stimulus because the brain is still busy processing a first stimulus.

Resting Potential

Characterized in the notes as the delay in reacting to a second stimulus because the brain is still busy processing a first stimulus.

Reuptake

The process where a presynaptic neuron reabsorbs leftover neurotransmitters from the synaptic gap after they finish sending a signal.

Firing Threshold

The minimum level of electrical stimulation required inside a neuron to trigger an action potential.

Multiple Sclerosis

A condition involving direct neurological damage to the central nervous system characterized by damaged myelin and exposed nerve fibers.

Myasthenia Gravis

A chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles due to antibodies blocking acetylcholine receptors.

Excitatory Neurotransmitters

Chemical messengers that increase the likelihood that a receiving neuron will fire an action potential.

Inhibitory Neurotransmitters

Chemical messengers that decrease the likelihood that a receiving neuron will fire an action potential.

Dopamine

A neurotransmitter in the brain that drives motivation, anticipation, and pleasure.

Serotonin

A neurotransmitter that plays a central role in bodily function, mood regulation, and behavior.

Norepinephrine

A neurotransmitter that mediates arousal, action, alertness, and memory regulation.

Glutamate

A primary neurotransmitter driving nearly all fast communication between brain cells; plays a key role in learning and memory.

GABA

The primary inhibitory neurotransmitter that slows down and stops nerve signals, functioning to control anxiety and regulate mood.

Endorphins

Neurotransmitters released by the body that relieve pain and regulate mood.

Substance P

A key signaling molecule in the central and peripheral nervous systems that links physical pain, stress responses, and emotional regulation.

Acetylcholine

The primary neurotransmitter responsible for learning, memory, attention, stress, arousal, and emotional processing.

Adrenaline

A stress hormone and neurotransmitter produced by the adrenal glands that plays an important role in the fight-or-flight response by increasing heart rate and widening air passages.

Leptin

A protein and peptide hormone produced by fat cells that signals the brain to regulate hunger and body weight.

Ghrelin

A peptide hormone, often called the 'hunger' or 'go' hormone, that signals the hypothalamus that the stomach is empty.

Melatonin

A hormone produced by the pineal gland in the brain that regulates the body's sleep-wake cycle in response to darkness.

Oxytocin

A peptide hormone produced in the hypothalamus and released by the pituitary gland that facilitates social bonding, trust, uterine contractions during labor, and milk ejection.

Agonist

A molecule that binds to a cell receptor and activates it to produce a biological response.

Antagonist

A molecule that binds to a receptor without activating it, thereby blocking or dampening the effects of agonists.

Reuptake Inhibitors

A type of chemical substance that blocks the reabsorption of neurotransmitters by the presynaptic neuron that released them.

Brainstem

The stalk-like lower part of the brain that connects the cerebrum and cerebellum to the spinal cord, acting as the body's primary control center.

Medulla

The lowest, stem-like part of the brainstem that connects the higher levels of the brain to the spinal cord.

Reticular Activating System (RAS)

A net-like network of neurons located deep within the brainstem that regulates wakefulness, consciousness, and the sleep-wake cycle.

Reward Center

A group of interconnected brain structures that process motivation and the drive to repeat behaviors that feel good or satisfy survival needs.

Cerebellum

A major structure located at the back and base of the brain that coordinates movement, balance, and posture, while also contributing to cognitive and emotional functions.

Cerebral Cortex

The outermost layer of gray matter of the cerebrum in the human and mammalian brain, folded to increase total surface area.

Cerebral Hemispheres

The two symmetrical halves of the cerebrum, which constitutes the largest part of the brain responsible for thought and voluntary movement.

Limbic System

A complex network of brain structures located beneath the cerebral cortex that controls emotions, memory, behavior, and basic survival drives.

Thalamus

A pair of egg-shaped gray matter structures deep in the center of the brain that acts as the body's primary information relay station.

Hypothalamus

A small, cone-shaped structure located deep in the center of the brain that serves as the main control center for maintaining internal balance (homeostasis).

Pituitary Gland

A small, pea-sized endocrine gland located at the base of the brain that secretes growth hormone as well as hormones related to reproduction and metabolism.

Amygdala

A pair of almond-shaped clusters of nuclei deep within the temporal lobes of the brain that functions as part of the limbic system for emotional processing and threat detection.

Hippocampus

A C-shaped structure in the medial temporal lobe of the brain that manages emotions, learning, spatial memory, and short- and long-term memory formation.

Corpus Callosum

The largest white matter structure in the human brain, consisting of $200$ to $300\text{ million}$ nerve fibers (axons) that bridge and share information between the two cerebral hemispheres.

Frontal Lobes

The region at the front of the brain responsible for voluntary movement and executive functions such as planning, problem-solving, and reasoning.

Parietal Lobes

The middle-upper section of the cerebral cortex that integrates sensory input from the body and handles spatial awareness.

Occipital Lobes

The smallest of the four main lobe pairs, located at the back of the head, functioning as the primary hub for visual processing and object/face recognition.

Prefrontal Cortex (PFC)

The anterior-most part of the frontal lobe that manages higher-level planning, problem-solving, and abstract reasoning.

Motor Cortex

A region within the frontal lobe that sends direct neural signals down the spinal cord to control voluntary movement and coordination.

Temporal Lobes

A major region of the cerebral cortex located on each side of the head, responsible for auditory processing and language comprehension.

Somatosensory Cortex

A strip in the parietal lobe containing a topographic map of the body (sensory homunculus), where physical sensitivity dictates the amount of cortical space assigned to each body part.

Association Areas

Cortical regions that integrate raw sensory data with memory, visual cues, and language rather than processing primary motor or sensory signals directly.

Split-Brain Condition

A neurological condition that occurs when the corpus callosum is severed or missing, preventing direct communication between the two cerebral hemispheres.

Hemispheric Specialization

The distinct functional lateralization of the brain, where the left hemisphere specializes in movement, language, speech, and logic, while the right hemisphere specializes in recognition, spatial processing, sounds, and melodies.

Broca's Area

A region in the frontal lobe of the dominant hemisphere (usually left) that controls speech production, motor planning for language, and grammatical structuring.

Wernicke's Area

A region in the temporal lobe of the dominant hemisphere essential for language comprehension and processing spoken and written words.

Aphasia

A neurological communication disorder caused by damage to the brain's language centers that impairs a person's ability to speak, understand, read, or write while leaving general intelligence intact.

Contralateral Organization

The structural arrangement in the nervous system where each cerebral hemisphere receives sensory information from and controls motor actions on the opposite side of the body.

Neuroplasticity

The lifelong ability of the brain and nervous system to reorganize its physical structure, functions, and neural connections in response to learning, experience, or injury.

Electroencephalogram (EEG)

A medical test that measures and records the electrical activity of the brain using small metal sensors (electrodes) attached to the scalp.

Functional Magnetic Resonance Imaging (fMRI)

A non-invasive, radiation-free neuroimaging technique that measures and maps brain activity by tracking changes in blood flow and oxygen levels.

Case Studies (in Neuroscience)

In-depth scientific investigations of a single patient or small group who suffered a unique brain injury, disease, or surgical intervention.

Lesioning Procedure

A neurosurgical technique that selectively destroys or removes a specific, small area of brain tissue to treat severe neurological disorders or investigate brain function.