Unit 3 Flashcards
What is “behavioral genetics,” and what does it study?
- Behavioral Genetics: The field examining how heredity (genes) and environment jointly shape behaviors, personality, cognition, and mental health.
- Goals: Disentangle the relative contributions of genetic makeup versus environmental factors in various traits.
What are the three primary research methods in behavioral genetics?
- Twin Studies: Compare identical (100% shared genes) vs. fraternal twins (≈50% shared genes).
- Family Studies: Trace trait prevalence across generations.
- Adoption Studies: Compare adopted individuals to both biological and adoptive parents to discern genetic vs. environmental influences.
How do genes and chromosomes influence behavior, and what are polygenic traits?
- Chromosomes: Humans typically have 23 pairs; each pair consists of one chromosome from each parent.
- Genes: Segments of DNA that code for proteins; many behaviors and physical traits have multiple genetic influences.
- Polygenic Traits: Influenced by multiple genes and further shaped by the environment (e.g., height, intelligence).
Distinguish between genotype and phenotype.
- Genotype: An individual’s complete genetic makeup, fixed at conception.
- Phenotype: The observable expression of traits (physical, behavioral) resulting from the interaction of genes and the environment.
What are the two major types of cells in the nervous system?
- Neurons: The primary signaling cells; they transmit electrical impulses and release neurotransmitters.
- Glial Cells: Support cells that maintain homeostasis, form myelin sheaths, and help repair the nervous system.
Briefly outline how neurons communicate.
- Resting Potential: Neuron is polarized (negative charge inside).
- Action Potential: Rapid depolarization travels down the axon.
- Synaptic Transmission: Neurotransmitters released into the synapse bind to receptors on the postsynaptic neuron, influencing its likelihood of firing.
Name a few key neurotransmitters and their general functions.
- Acetylcholine (ACh): Muscle activation, memory, attention.
- Dopamine (a monoamine): Motivation, reward, movement.
- Norepinephrine (a monoamine): Alertness, arousal.
- Serotonin (a monoamine): Mood, appetite, sleep.
- GABA: Main inhibitory neurotransmitter, calming effect.
- Endorphins: Natural pain relief, “feel-good” chemicals.
How do agonists and antagonists affect neurotransmitter activity?
- Agonists: Enhance or mimic neurotransmitters (e.g., some Parkinson’s meds mimic dopamine).
- Antagonists: Block or reduce neurotransmitter effects (e.g., antipsychotics blocking dopamine receptors).
What are the major divisions of the brain and their primary functions?
- Hindbrain (Cerebellum, Pons): Basic life functions, motor coordination, sleep.
- Midbrain: Integrates sensory processes, manages reflexive responses.
- Forebrain:
- Thalamus: Sensory relay station.
- Hypothalamus: Regulates hunger, thirst, temperature, and hormones.
- Limbic System (Hippocampus, Amygdala): Emotion, motivation, memory.
- Cerebrum/Cerebral Cortex: Higher-order thinking, language, problem-solving.
Name and describe the four lobes of the cerebral cortex
- Frontal: Executive functions, planning, decision-making, motor control (includes Broca’s area for speech production).
- Parietal: Processes tactile (touch) and spatial information.
- Temporal: Auditory processing, language comprehension (Wernicke’s area), memory.
- Occipital: Primary visual processing center.
Contrast Broca’s area and Wernicke’s area.
- Broca’s Area (Left Frontal): Speech production. Damage = difficulty forming speech.
- Wernicke’s Area (Left Temporal): Language comprehension. Damage = fluent but nonsensical speech.
What is lateralization, and how do the hemispheres communicate?
- Lateralization: Each hemisphere specializes in certain tasks (left often in language/analysis; right in spatial/creative tasks).
- Corpus Callosum: Large bundle of fibers connecting hemispheres, enabling them to work together.
- Split-Brain Surgery: Cutting the corpus callosum reveals distinct hemisphere functions.
Why does damage to the left motor cortex affect the right side of the body?
Because sensory and motor pathways cross in the brainstem, the left hemisphere controls the right side of the body and vice versa.
What is plasticity, and why is it important?
Brain Plasticity: The ability of the brain to reorganize itself by forming new connections. It underlies learning, memory formation, and recovery from injury.
Define neurogenesis.
The process of creating new neurons, primarily in the hippocampus. This contributes to learning, memory, and adaptive changes over time.
Why are case studies (like patient H.M.) useful and what is a limitation?
- Usefulness: Help localize brain functions and reveal how damage affects behavior.
- Limitation: Unique circumstances may not generalize widely.
Differentiate lesioning from electrical stimulation of the brain (ESB).
- Lesioning: Deliberately damaging specific areas (often in animal models) to see how behavior changes.
- ESB: Applying mild electric currents to stimulate brain regions, revealing their functions.
What’s the difference between structural and functional brain imaging methods?
- Structural:
- CT: X-ray images for large-scale structure.
- MRI: Detailed, high-resolution images of brain anatomy using magnetic fields.
- Functional:
- EEG: Electrical brain activity patterns (e.g., in sleep studies).
- PET: Uses radioactive tracers to show metabolic activity.
- fMRI: Tracks blood flow to identify active brain regions during tasks.
How do hormones differ from neurotransmitters?
- Endocrine System: Glands releasing hormones into the bloodstream for slower, longer-lasting effects.
- Neurotransmitters: Rapid, localized signals between neurons.
- Hormones: Influence growth, metabolism, reproduction, mood; can have body-wide impacts.
Name a few major glands/hormones in the endocrine system.
- Pituitary (“master gland”): Controls growth, water balance, etc.
- Adrenal Glands: Release cortisol/adrenaline (stress response).
- Thyroid: Metabolic rate regulation.
- Gonads (Ovaries/Testes): Sex hormones (estrogen, testosterone) for reproduction and secondary sex traits.
What does evolutionary psychology study?
It explores how evolutionary pressures shaped human behavior, emotions, and thought processes. Behaviors like mate selection, fear responses, or social bonding are examined as adaptive traits from our ancestors.
Define “natural selection” and “adaptations,” giving an example.
- Natural Selection: Traits that enhance survival/reproduction become more common.
- Adaptations: Features or behaviors that improve an organism’s fitness.
- Example: Fight-or-flight response helped early humans respond quickly to threats.
Why might human social behaviors be considered evolved mechanisms?
As with physical traits (e.g., giraffes’ long necks), certain human social and cognitive behaviors likely evolved to navigate complex group life, foster cooperation, and enhance survival.
What is cerebrospinal fluid (CSF)?
A clear, colorless fluid circulating around the brain and spinal cord in the ventricles, subarachnoid space, and central canal.
List the primary functions of CSF.
- Cushioning and Protection: Absorbs shock to protect brain/spinal cord from injury.
- Maintains Intracranial Pressure: Helps regulate pressure in the skull.
- Nutrient Delivery and Waste Removal: Transports nutrients to neural tissue and removes metabolic byproducts.
Where is CSF produced, and how does it circulate?
- Production: Mainly by the choroid plexus in the brain’s ventricles.
- Path of Circulation: Flows through the ventricles → subarachnoid space → reabsorbed into the bloodstream via arachnoid granulations.
Why is CSF critical for proper brain function?
Creates a stable chemical environment, helps buffer against physical shocks, and ensures essential nutrients reach the CNS while removing waste.
Why are case studies of individuals with brain injuries valuable to research?
- Insight into Brain-Behavior Links: Reveals how damage to certain brain regions affects cognition and behavior.
- Neuroplasticity: Shows how the brain compensates for injury over time.
What are the key limitations of brain-injury case studies?
- Small Samples: Findings may not generalize to everyone.
- Individual Differences: Pre-existing conditions and injury context vary greatly.
- Subjective Accounts: Can complicate data interpretation and reduce reliability.
How is lesioning used to study brain function?
Lesioning: Deliberately damaging targeted brain areas (e.g., chemicals, surgical methods) to see how behavior and abilities change, linking specific brain regions to distinct functions
How does electrical stimulation of the brain (ESB) help researchers?
- ESB: Delivers mild electrical currents to targeted brain areas.
- Purpose: Temporarily activate or inhibit these areas and observe real-time changes in movement, sensation, or behavior.
Which subjects are typically used in lesioning and ESB studies?
- Commonly: Animals (rodents, primates) for controlled experiments.
- Occasionally: Humans (clinical settings) where therapeutic procedures allow for observation of brain function.
What does CT (Computed Tomography) show, and when is it especially useful?
- CT Scans: Use multiple X-ray angles to create cross-sectional images of the brain.
- Utility: Quickly identify tumors, bleeding, or large-scale structural issues—often used in emergency situations.
How does MRI (Magnetic Resonance Imaging) differ from CT?
- MRI: Uses strong magnetic fields and radio waves for high-resolution images of soft tissue.
- Advantage: Better for identifying subtle differences in gray vs. white matter and more detailed structural features.
What is EEG (Electroencephalography), and what does it measure?
- EEG: Records electrical activity in the brain via scalp electrodes.
- Real-Time Data: Monitors brainwaves during tasks like sleep studies or detecting seizure patterns.
How do PET (Positron Emission Tomography) scans show brain activity?
- PET Scans: Inject a radioactive tracer, which highlights regions of high glucose metabolism.
- Usage: Identifies which brain areas are active during specific tasks or stimuli.
Explain how fMRI (Functional MRI) reveals brain function.
- fMRI: Detects changes in blood oxygen levels in the brain.
- Purpose: Locates which regions are active during tasks like memory, emotion, or problem-solving—providing a dynamic “map” of neural activity.
What is the main difference between structure-focused and activity-focused imaging techniques?
- Structure-Focused (CT, MRI): Provide anatomical snapshots of the brain’s shape, lesions, and other structural details.
- Activity-Focused (EEG, PET, fMRI): Reveal functional brain processes and real-time changes in neural activity.
Where is Broca’s Area located, and what is its primary function?
- Location: Left frontal lobe.
- Function: Produces and plans language (speech, grammar).
What happens when Broca’s Area is damaged?
- Broca’s Aphasia:
- Speech is slow, effortful, and halting.
- Difficulty forming complete sentences.
- Language comprehension remains relatively intact.
Where is Wernicke’s Area located, and what is its primary function?
- Location: Left temporal lobe (back part).
- Function: Processes and comprehends spoken and written language.
What are the effects of damage to Wernicke’s Area?
- Wernicke’s Aphasia:
- Fluent but nonsensical (or “word salad”) speech.
- Significant difficulty understanding others.
What is split-brain surgery, and why is it performed?
- Definition: Cutting the corpus callosum to separate the hemispheres.
- Purpose: Treats severe epilepsy by preventing seizures from spreading across hemispheres.
What are some effects of split-brain surgery?
- Reduces seizures but can cause coordination issues on tasks needing both hemispheres.
- Reveals differences in how each hemisphere processes information.
