Biological Bases of Behavior AP PSYCHOLOGY

ap psychology

what is the nature vs nurture debate?

Nature vs. nurture is the debate over the relative contributions that genes & experience make to the development of psychological traits and behaviors.

how does the nature vs nurture debate relate to psychology?

nature means the biological factors of a person (genetics), and nurture can refer to upbringing.

how does evolutionary perspective explain behavior?

It uses the principles of natural selection to study behavior.

Natural selection

The biological and physical traits that best enable organisms to survive and reproduce.

survival of the fittest

Variations in the physical features of organisms that tend to benefit an individual in their own environments.

Eugenics

The theory of “racial improvement”, or selectively breeding humans to promote characteristics.

Twin studies

Comparing data from identical and fraternal twins allow researchers to understand the role of genetics & environment on different traits.

Adoption studies

Personality traits, people who were adopted have been seen as more similar to their biological parents than their adoptive parents, showing genetic influence is stronger. If it’s the opposite, environmental influence is stronger.

Family studies

Search for traits and diseases that tend to be shared by family members.

Central nervous system

The brain & spinal cord, is the body’s decision maker.

Peripheral nervous system

The sensory & motor neurons that connect the CNS to the rest of the body. Responsible for gathering information & transmitting CNS decisions to other body parts.

Autonomic nervous system

The part of the PNS that controls the glands & muscles of the internal organs (such as the heart). It’s sympathetic division arouses; parasympathetic calms.

Parasympathetic nervous system

Calms the body, conserving its energy

Sympathetic nervous system

Arouses the body, mobilizing its energy

How do the sympathetic and parasympathetic nervous systems work together?

They keep our bodies in a steady, internal state called homeostasis.

Somatic nervous system

The division of the PNS that controls the body’s skeletal muscles.

Motor neurons

Efferent. Carry instructions from the CNS outward to the body’s muscles & glands.

Sensory neurons

Afferent. Carry messages from the body’s tissues and sensory receptors inward to the brain and spinal cord for processing.

Interneurons

Within the brain & spinal cord. Communicate internally and process information between the sensory inputs and motor outputs.

Reflex arc

Spinal reflex pathway. Composes of a single sensory neuron & single motor neuron. Communicate through spinal cord interaction.

Dendrite

Bushy, receive and integrate messages, conducting impulses toward the cell body.

Soma

Cell’s life-support center.

Axon

Passes on messages through its branches to other neurons or to muscles or glands.

Axon terminals or Terminal buttons

Form junctions with other cells.

Myelin sheath

Insulates axons & speeds their impulses.

Nodes of Ranvier

Allows ions to diffuse in and out of the neuron, sending the electrical signal down the axon

Glial cells

Support, nourish, and protect neurons.

Neural transmission

The process where a neuron sends a message by firing and impulse until it reaches the synapse. Once it reaches the end of the axon, it stimulates the release of neurotransmitters and carry the message with them into the synapse, & bind receptor sites on the receiving neuron. Excess neurotransmitters are reabsorbed, drift away, or are broken down by enzymes.

Threshold

The level of stimulation required to trigger a neural impulse.

Action potential

A neural impulse; brief electrical charge that travels down the axon.

Resting potential

Positive outside/Negative inside state of axon fluid.

Refractory Period

Resting process after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

Synapse or synaptic cleft

Junction between axon tip of the sending neuron & dendrite or cell body of the receiving neuron.

Reuptake

A neurotransmitters reabsorption by the sending neuron.

How do disruptions in the nervous system lead to disorders such as multiple sclerosis or myasthenia gravis?

when the myelin sheath degenerates, the deterioration leads to diminished control & slower reaction time?

What is the difference between excitatory and inhibitory neurotransmitters?

Excitatory: makes the next neuron more likely to fire

Inhibitory: makes the next neuron less likely to fire

Acetylcholine (ACh)

Enables muscle action, learning and memory. Linked to Alzheimer’s disease, ACh-producing neurons deteriorate.

Dopamine

Influences movement, learning, attention, emotion. Oversupply linked to Schizophrenia. Undersupply linked to tremors and decreases mobility in Parkinson’s disease.

Serotonion

Affects mood, hunger, sleep, and arousal. Undersupply linked to depression.

Norepinephrine

Helps control alertness and arousal. Undersupply can depress mood.

GABA

A major inhibitory neurotransmitter. Undersupply linked to seizures, tremors, and insomnia.

Glutamate

A major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain, producing migraines and seizures.

Endorphins

Neurotransmitters that influence the perception of the pain or pleasure. Oversupply with opioid drugs can suppress the body’s natural endorphin supply.

Substance P

Involved in pain perception & immune response. Oversupply can lead to chronic pain.

How does the endocrine system transmit information and interact with the nervous system?

The body’s “slow” chemical communication system; a set of glands & fat tissue that secrete hormones in the bloodstream. Messages travel along the bloodstream. The system and the nervous system produce molecules that act on receptors elsewhere.

How are hormones different than neurotransmitters?

They are chemical messengers that are manufactured by the endocrine glands.

Adrenaline

Increase heart rate, blood pressure and blood sugar, fight-or-flight response. Release points at adrenal glands on top of kidneys, release epinephrine and norepinephrine.

Ghrelin

Hunger arousing hormone. Release points at brain, small intestine, pancreas, and stomach.

Leptin

Hunger suppressing hormone. Release point at white adipose tissue (body fat).

Melatonin

Sleep inducing hormone. Release point at pineal gland in your brain.

Oxcytocin

Enables orgasm, for women labor contractions and milk flow while nursing. Aids social support. Release point in the hypothalmus.

Agonists

Mimics neurotransmitters, activates neurons

Antagonists

Decrease a neurotransmitter’s action by blocking production or release.

Reuptake inhibitors

Stops or delay the body from reabsorbing a substance called serotonin.

What are psychoactive drugs and how do they impact our body?

A chemical substance that alters the brain, causing changes in perceptions and moods. It can cause substance disorder. They stimulate, inhibit, and mimic the activity of neurotransmitters.

Hallucinogens

Mind manifesting drugs that distort perceptions and evoke sensory images in the absence of sensory input.

Depressants

Drugs that reduce neural activity and slow body functions (alcohol, tranquilizers, opioids).

Stimulants

Drugs that excite neural activity and speed up body functions.

Opioids

Opium and its derivatives; depress neural activity, temporarily lessening the pain and anxiety.

Lesion

Brain lesions may occur naturally (from disease or trauma) during surgery, or experimentally. They would be used to test the role a region plays in a particular function.

EEG

Electrodes placed on the scalp measure electrical activity in neurons. Used when diagnosing brain conditions, such as epilepsy.

MRI

People sit or lie down in a chamber that uses magnetic fields and radio waves to provide a map of brain structure. Used to diagnose conditions that affect soft tissue, such as tumors or brain disorders.

fMRI

Measures blood flow to brain regions by comparing continuous MRI scans. Used for pre-surgical planning purposes.

What is “split brain”, and why is the procedure done?

A condition resulting from surgery that isolates the brain’s two hemispheres by cutting the corpus collosum connecting them. It is to treat epilepsy and prevent seizures.

Left hemisphere

Logic and language

Right hemisphere

Creativity and intuition

What is contralateral control?

Describes how each hemisphere of the brain controls the contralateral side of the body.

Consciousness

Our subjective awareness of ourselves and our environment.

NREM sleep

Deep sleep stage

REM sleep

Your eyes move rapidly, and other body systems are still active.

Hypnagogic sensations

Bizzarre experiences such as jerking or feeling of falling, floating weightlessly.

Activation synthesis

Dreams are the brain’s attempt to synthesize random neural activity.

Memory consolidation

Dreams help us sort out the day’s events and consolidate them in memory.

Narcolepsy

Uncontrollable sleep attacks by overwhelming sleepiness.

REM sleep behavior disorder

Acting out content of dreams while asleep, including vocalizing, kicking, or punching

Somnambulism

Repeated episodes of complex motor behavior, such as walking while asleep.

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Perception

When our brain is organized and interprets sensory information, enabling us to reorganize objects and events as meaningful.

Absolute thresholds

The minimum stimulus energy needed to detect a particular stimulus 50% of the time.

Difference thresholds

The minimum difference between two stimuli required for detection 50% of the time.

Just-noticeable difference

The smallest level of stimulation that a person can detect 50% of the time.