Unit 1: Biological Bases of Behavior

Comprehensive review flashcards covering biological bases of behavior, including nervous system divisions, neuronal signaling, neurotransmitters, brain anatomy, endocrine mechanisms, and sleep processes.

What is epigenetics?

The study of environmental influences on gene expression that occur without a change in the underlying DNA sequence.

What components make up the Central Nervous System?

The brain and the spinal cord.

What is the primary function of the Somatic Nervous System?

It controls the body's voluntary movements of skeletal muscles and transmits sensory information to the Central Nervous System.

How do the Sympathetic Nervous System and Parasympathetic Nervous System differ in function?

The Sympathetic Nervous System arouses the body and mobilizes energy for fight-or-flight, whereas the Parasympathetic Nervous System calms the body and conserves energy for rest and digestion.

What is the primary role of dendrites in a neuron?

Branch-like extensions that receive incoming messages and electrical impulses from other cells and carry them toward the soma.

What is the function of the myelin sheath?

A layer of fatty tissue that insulates the axon and significantly increases the transmission speed of neural impulses.

What is meant by the all-or-none law of neural firing?

A neuron either fires completely with full electrical intensity if the threshold is met, or it does not fire at all; the impulse strength does not vary.

What occurs during the refractory period of a neuron?

A brief recovery period following an action potential during which the neuron is unable to fire another action potential until resting potential is restored.

What is reuptake in neural communication?

The reabsorption of excess neurotransmitter molecules from the synaptic gap back into the presynaptic terminal buttons.

How does a reputake inhibitor work?

It blocks the reabsorption of neurotransmitters by the sending neuron, leaving higher concentrations of neurotransmitter active in the synapse.

What is the difference between afferent (sensory) neurons and efferent (motor) neurons?

Afferent neurons carry sensory signals inward from receptors to the central nervous system, while efferent neurons carry motor commands outward from the central nervous system to muscles and glands.

What role do interneurons play in a reflex arc?

They process signals locally in the spinal cord, directly connecting sensory and motor pathways to execute rapid, automatic responses before signals reach the brain.

What are glial cells and what is their role?

Non-neuronal cells in the nervous system that nourish, protect, support, and insulate neurons.

What primary functions are associated with the neurotransmitter ACh (acetylcholine)?

Enabling muscle contraction, as well as playing critical roles in learning and memory.

What functions are mediated by dopamine?

Motor movement, pleasure, motivation, alertness, and reward-seeking behavior.

What is the primary role of Substance P?

A neurotransmitter primarily involved in transmitting pain messages to the central nervous system.

How do GABA and Glutamate differ in their synaptic effects?

GABA is the brain's major inhibitory neurotransmitter, while Glutamate is the major excitatory neurotransmitter involved in memory and learning.

Why is the pituitary gland considered the 'master gland' of the endocrine system?

It releases hormones that regulate and trigger the hormone production of other endocrine glands under the direct direction of the hypothalamus.

How do ghrelin and leptin influence appetite differently?

Ghrelin is a hormone that triggers the sensation of hunger, whereas leptin is a hormone produced by fat cells that signals satiety and fullness.

What is the difference between agonists and antagonists?

Agonists bind to receptors and mimic or amplify the actions of a neurotransmitter, whereas antagonists bind to receptors to block or inhibit neurotransmitter actions.

How do depressents affect the central nervous system?

They reduce neural activity and slow down bodily functions, often by increasing GABA activity.

What vital functions are regulated by the medulla in the brain stem?

Involuntary autonomic functions essential for survival, including heartbeat, respiration, and blood pressure.

What is the function of the reticular formation?

A nerve network running through the brainstem that controls physiological arousal, alertness, and attention.

What is the primary role of the thalamus?

Acting as the brain's sensory switchboard, directing sensory information (except smell) to corresponding areas in the cerebral cortex.

What are the primary functions of the cerebellum?

Coordinating voluntary muscle movements, maintaining balance and posture, and storing procedural memories.

What structures make up the limbic system, and what is its main function?

It includes the amygdala, hippocampus, and hypothalamus, functioning together to regulate emotions, memory, and basic physiological drives.

What is the key cognitive role of the hippocampus?

Consolidating new explicit (declarative) memories and transferring them to the cortex for long-term storage.

What is the function of the amygdala?

A limbic structure involved in processing emotion, particularly fear, anger, and aggression.

What function is localized to Broca’s Area, and what deficit characterizes Broca's aphasia?

Located in the left frontal lobe, it controls speech production; damage causes expressive aphasia, characterized by halting, labored speech despite preserved comprehension.

What function is localized to Wernicke’s Area, and what deficit characterizes Wernicke's aphasia?

Located in the left temporal lobe, it processes language comprehension; damage causes receptive aphasia, where speech is grammatically fluent but meaningless and comprehension is impaired.

Where is the somatosensory cortex located and what is its role?

Located in the parietal lobes, it registers and processes incoming tactile sensations such as touch, temperature, and pain from across the body.

What are the primary sensory processing functions of the occipital lobes and temporal lobes?

The occipital lobes process visual input, while the temporal lobes process auditory input and speech recognition.

What is contralateral hemispheric organization?

The structural arrangement where the left hemisphere receives sensory input from and controls motor actions of the right side of the body, and vice versa.

What is severed during split brain surgery?

The corpus callosum, severing communication between the left and right cerebral hemispheres.

What is neuroplasticity?

The brain's capacity to modify its neural connections, reorganize pathways, and adapt in response to learning, experience, or physical damage.

In neuroscience, what does the technique of lesioning refer to?

The deliberate destruction or removal of a specific area of brain tissue to study its behavioral and physiological functions.

What is REM Rebound?

The increased frequency and duration of rapid eye movement (REM) sleep that occurs following periods of REM sleep deprivation.

What is somnabulism and during which sleep stage does it occur?

Sleepwalking, which occurs during deep non-rapid eye movement (NREM) slow-wave sleep.

How do narcolepsy and sleep apnea differ as sleep disorders?

Narcolepsy causes uncontrollable, sudden attacks of overwhelming daytime sleepiness and direct collapse into REM sleep, while sleep apnea involves intermittent cessations of breathing during sleep leading to repeated awakenings.

What characterizes REM sleep behavior disorder?

A sleep condition where the typical motor paralysis (atonia) of REM sleep fails, causing individuals to physically act out their dreams.

What does the activation synthesis theory state regarding dreams?

Dreams are the cerebral cortex's attempt to synthesize and impose narrative meaning onto random neural activity originating from the brainstem during REM sleep.

What does the consolidation theory suggest about the role of sleep?

Sleep serves to stabilize and consolidate memory traces acquired during wakefulness, transferring them from temporary storage into long-term memory networks.

What physiological characteristics define NREM (non-rapid eye movement) sleep?

A progression through stages of decreasing physiological arousal, characterized by slowed respiration, reduced heart rate, progressively slower brain wave patterns such as delta waves, and tissue repair.

Why is REM sleep often characterized as 'paradoxical sleep'?

Internal physiological arousal and brain wave activity closely resemble alert wakefulness, while external voluntary motor control is suppressed through muscle atonia.

What primary restorative functions are supported by sleep?

Enables cellular and tissue repair, releases human growth hormone, strengthens immune defense, clears neural metabolic waste, and reorganizes cognitive pathways.

What symptoms define the sleep disorder insomnia?

Persistent difficulty initiating sleep, maintaining sleep through the night, or waking prematurely, resulting in non-restorative sleep and impaired daytime functioning.

What executive cognitive functions are governed by the prefrontal cortex?

Abstract reasoning, forward planning, cognitive flexibility, risk evaluation, decision-making, working memory maintenance, and conscious impulse inhibition.

What is the primary role of the motor cortex?

A band of cortex at the rear of the frontal lobes that plans, coordinates, and executes voluntary muscular movements in contralateral regions of the body.

What sensory and spatial functions are carried out by the parietal lobes?

Processing somatosensory sensations like touch, pain, and temperature, alongside integrating multimodal sensory data for spatial orientation and mathematical calculations.

What physiological duties are coordinated by the pons within the brain stem?

Serving as a communication bridge between the cerebellum and higher brain structures, assisting in respiration and facial control, and initiating motor paralysis during REM sleep.

How does the cerebrum differ structurally from the cerebral cortex?

The cerebrum encompasses the entire bilateral bulk of the upper brain, including internal subcortical tracts, whereas the cerebral cortex is specifically the outer, wrinkled mantle of gray matter.

What role does melatonin play in sleep-wake regulation?

A hormone produced by the pineal gland during darkness that lowers physiological arousal and signals to the body that it is time to transition into sleep.

What behavioral and physiological effects are driven by oxytocin?

Facilitating maternal labor contractions and milk letdown, while physiologically fostering trust, social affiliation, parental bonding, and emotional attachment.

What bodily effects are triggered by adrenaline (epinephrine) released from the adrenal glands?

Surges blood pressure, accelerates heart rate, dilates bronchial passages, and mobilizes blood glucose to optimize immediate physical capacity for fight-or-flight emergencies.

How does signal transmission in the endocrine system differ from that of the nervous system?

Hormones travel systemically via blood circulation, resulting in slower onset but longer-lasting and more widespread effects compared to targeted, millisecond electrochemical impulses.

What is the excitation threshold of a neuron?

The minimum level of depolarization (typically around $-55\,\text{mV}$) required to trigger the all-or-none opening of voltage-gated channels and initiate an action potential.

What occurs during the depolarization phase of an action potential?

Voltage-gated sodium channels open rapidly, allowing an influx of positively charged sodium ions ($\text{Na}^+$) to enter the axon and shift the internal charge from negative to positive.

How do excitatory postsynaptic potentials (EPSPs) differ from inhibitory postsynaptic potentials (IPSPs)?

EPSPs depolarize the postsynaptic membrane to bring the membrane potential closer to threshold, whereas IPSPs hyperpolarize the membrane, decreasing the likelihood of an action potential.

What is the structural role of an axon within a neuron?

A singular elongated projection that conducts electrical impulses away from the cell body toward distant synaptic junctions and downstream targets.

What activity takes place within the terminal buttons during synaptic transmission?

Incoming action potentials stimulate synaptic vesicles to fuse with the cell membrane, releasing stored neurotransmitter molecules outward into the synaptic cleft.