AP Psychology Unit 2: Biological Bases of Behavior

use advanced technologies to study the links between biological processes and psychological processes

biological psychologist

What four things have researchers seeking to understand the biology of the mind discovered?

1. Our adaptive brain is wired by experiences.

2. Among body cells there are nerve cells (neurons) that “talk” to each other by sending chemical messages over a tiny gap. (synaptic gap)

3. Certain brain systems serve certain functions

4. We use the information from these systems to construct our experiences of sight and sound, meaning and memory, and pain and passion.

What does it mean when it’s said that humans are biopsychosocial systems?

We are composed of smaller bodily systems and then a part of our own families, communities, and cultures. To understand our behavior, we must study how our biological, psychological, and social systems work.

Why is it a benefit that there is not much difference between the brains of humans and animals?

Researchers can study animals’ brains to learn about our own.

a nerve cell; basic building block of the nervous system

neuron

• contains the neuron’s nucleus

• The neuron’s “life support center”

• Also known as the soma

cell body

branching extensions that receive and integrate messages, conducting impulses toward cell body

dendrites

neuron extension that passes messages through branches to other neurons, muscles, or glands

axon

fatty tissue layer that encases axon to insulate it and speed up impulses

myelin sheath

How is the myelin sheath related to multiple sclerosis (MS)?

Multiple sclerosis occurs when the myelin sheath degenerates.

cells that support, nourish, and protect neurons; play a role in learning, thinking, and memory

glial cells

neural impulse; brief charge that travels down the axon

neuron’s action potential

What events have to occur in order for neurons to fire?

Ions are exchanged through the neuron’s chemistry-to-electricity process. The axon’s surface is selectively permeable; meaning it is picky about what it lets into its gates. The positive outside/negative inside state is called the resting potential.

How do the security parameters change when a neuron fires (Include the term depolarize)? How often can this process repeat?

The first section of axon opens and positively charged sodium ions, attracted by the negative interior, flood in. The loss of inside/outside charge difference called depolarization, causes other sections to open like falling dominos. This inflow is the action potential. Occurs 100-1000 times/second.

What are excitatory signals and inhibitory signals?

Excitatory signals press a neuron’s gas pedal, inhibitory signals press the break. If excitatory signals exceed inhibitory signals, an action potential is triggered.

The level of stimulation required to trigger a neural impulse

threshold

In neural processing, a brief resting pause after a neuron has fired; more action potentials cannot occur until the axon returns to its resting state.

refractory period

a neuron’s reaction of either firing or not firing

all-or-none response

The meeting point between the axon of one neuron and the dendrites of another. Tiny gap in between them is called the synaptic gap.

synapse

Chemical messengers that cross the synaptic gap. They bind to the receptors of the receiving neuron, sending an impulse

neurotransmitters

Excess neurotransmitters are reabsorbed by the sending neuron

reuptake process

Particular neurotransmitters affect specific _________ and ________.

behaviors; emotions

Enables muscle action, learning, and memory - In Alzheimer’s disease, neuron’s that produce this deteriorate.

Acetylcholine (ACh)

Influences movement, learning, attention, and emotion - Oversupply is linked to schizophrenia, undersupply is linked to tremors and decreased mobility in Parkinson’s disease.

Dopamine

Affects mood, hunger, sleep, and arousal - Undersupply linked to depression. Some antidepressants drugs raise serotonin levels.

Serotonin

Helps control alertness and arousal - Undersupply can depress mood.

Norepinephrine

A major inhibitory neurotransmitter - Oversupply can overstimulate the brain, producing migraines or seizures. (Why some people avoid MSG, monosodium glutamate, in food.

GABA (Gamma aminobutyric acid)

Natural opiate-like neurotransmitters linked to pleasure and pain control. Can cause runners high

Endorphins

What happens when the brain is flooded with opiate drugs such as heroin, and morphine?

The brain maintains chemical balance by suppressing its own natural opiates. When the drug is withdrawn, the brain may be deprived of natural opiates, causing discomfort.

What is the difference between an agonist and an antagonist?

Agonists increase a neurotransmitter’s action, an antagonist decreases or blocks it.

The body’s fast, electrochemical communication network, consisting of all nerve cells of the peripheral and central nervous systems.

Nervous system

Brain and spinal cord

Central nervous system

The sensory and motor neurons that connect the central nervous system to the rest of the body

Peripheral nervous system

Bundled axons form neural cables that connect central nervous system to muscles, glands, and sensory organs

Nerves

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

Sensory neurons carry messages from the body to the brain and motor neurons carry instructions from the brain to the body.

Neurons within the central nervous system that communicate internally; process information between sensory inputs and motor outputs

Interneurons

The division of the peripheral nervous system that controls the skeletal system

Somatic nervous system

Part of the peripheral nervous system that controls glands and muscles of internal organs

Autonomic nervous system

Division of autonomic nervous system that calms the body, conserving energy

parasympathetic nervous system

Division of autonomic nervous system that arouses body, mobilizing energy

Sympathetic nervous system

What does “the brain enables our humanity” mean?

It is the center of how we think, feel, and act.

How many neurons are in the central nervous system?

86 billion

Clusters of brain neurons

Neural networks

Neurons that ____ together ____ together, helping learning occur.

fire; wire

What is the spinal cord and how does it work?

A two-way information highway connecting the peripheral nervous system and the brain. Ascending neural fibers send up sensory information and descending neural fibers send back motor-control info.

Simple, automatic response to sensory stimuli (knee-jerk reaction)

Reflexes

what happens when the spinal cord is severed?

You wouldn’t feel anything from your paralyzed body part and below

The body’s slow, chemical communication system; secretes hormones into bloodstream

Endocrine system

Chemical messengers manufactured by glands in the endocrine system; travel through bloodstream and affect other tissues.

Hormones

What happens when hormones act on the brain?

They influence our interest in sex, food, and aggression.

How is the endocrine system similar to the nervous system? How is it different?

Some hormones are chemically identical to neurotransmitters. The nervous system is fast, and the endocrine system is slow. Endocrine messages outlast neural ones.

Pair of glands above kidneys, that secrete epinephrine and norepinephrine that arouse body during stress

Adrenal glands

The endocrine systems most influential gland. Under the control of the hypothalamus, this gland regulates growth and controls other endocrine glands.

Pituitary gland

Explain the immediate reaction that happens when you step on a piece of glass in terms of neurons.

The sensory neurons in your foot send a message up to your brain that notifies it of pain. The interneurons take the message from your foot and process it, sending it up to your brain. The motor neurons receive the message from the interneurons and send an instruction to your foot to pull away. This all happens instantly.

Tissue destruction; a brain ______ is a naturally or experimentally caused destruction of brain tissue.

Lesion

How else can scientists observe brain function?

• Stimulate parts of the brain

• Investigate individual neuron messages

• Snoop in on the chatter of billions of neurons

An amplified recording of the waves of electrical activity sweeping across the brain’s surface. Measured by electrodes on scalp. To examine brain activity caused by stimulus.

Electroencephalogram (EEG)

A brain imaging technique that measures magnetic fields from the brain’s natural, electrical activity

Magnetoecenphatography

Series of x-ray photographs from different angles, and combined by a computer into composite representation of a slice of the brain structure

Computed tomography (CT) scan

Visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a task

Positron emission tomography (PET) scan

Technique that uses magnetic fields and radio waves to produce computer generated images of soft tissue; shows brain anatomy

Magnetic resonance imaging (MRI)

Technique for revealing blood flow and brain activity by comparing successive MRIs; shows brain structure and function

Functional magnetic, resonance imaging (fMRI)

List a couple of examples how animals’ capacities come from brain structures.

• Shark: not so complex brain = basic survival functions (breathing, resting, feeding)

• Rodent: more complex brain = enables emotion, and memory

• Humans: most complex brain = foresight

What makes the brain of advanced mammals more complex?

Different/new brain systems

Oldest part and central core of the brain; responsible for automatic survival functions

Brainstem

Base of brainstem; controls heartbeat and breathing

Medulla

Nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal

Reticular formation

Egg-shaped structures; brain’s sensory control center

Thalamus

“Little brain“ at rear of brainstem; processes, sensory input, coordinating movement output, balance, enabling nonverbal learning and memory

Cerebellum

Helps cerebullum coordinate voluntary movements

Pons

These older brain functions all occur without ___ _________ ______ .

Any conscious effort

Neural system (amygdala, hypothalamus and hippocampus) located below cerebral hemispheres; associated with emotions and drives

Limbic system

What is the amygdala? Is this the only area that controls rage and fear? Explain.

Two lima bean sized neural clusters; linked to emotion. No, our brain is not organized structures according to our behavior categories. When we experience rage, there is natural activity in many areas of our brain.

Neural structure below thalamus; direct several maintenance activities (eating, drinking, body temperature) helps govern endocrine system via pituitary gland, and is linked to emotion and reward.

Hypothalamus

Why is the hypothalamus referred to as the reward center?

Because when stimulated, it gives us a sense of reward or pleasure, and leaves us going back for more.

Do humans have limbic systems for pleasure?

Yes, but they aren’t as strong as the rat’s (mild pleasure, but not a frenzy.)

Neural center (located in limbic system) helps process for storage, explicit (conscious) memories of facts and events

Hippocampus

The two cerebral hemispheres – form specialized work teams that enable perceiving, thinking, and speaking

cerebrum

The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control and sensory processing center.

Cerebral Cortex

What happens to the cerebral cortex as we “move up the ladder of animal life”?

It expands, tight genetic controls relax, and adaptability increases

just behind forehead; involved in speaking, muscle movement, making plans, and judgment.

Frontal lobe

Top of head toward rear; receives sensory input for touch and body position

parietal lobe

at the back of the head, receives info from visual fields

occipital lobe

above the ears; includes auditory areas, processes info for the opposite ear

temporal lobe

area at rear of frontal lobe that controls voluntary movements

motor cortex

What body areas occupy the greatest amount of cortical space? Why?

Fingers and mouth because they require precise control

Is it possible to move prosthetics just by thinking?

Yes. Scientists can observe brain signals associated with certain movements and program a computer to perform those same movements with just a thought.

An area at the front of the parietal lobes, processing body touch and movement sensation

Somatosensory cortex

What is the relationship between the sensitivity of a body region and the size of the sensory cortex area devoted to it?

The more sensitive the area, the larger the sensory cortex area

What additional areas provide input to the sensory cortex besides touch?

Visual and auditory; occipital and auditory cortex

Areas of cerebral cortex not involved in primary motor or sensory, but rather learning, speaking, remembering, and thinking.

Association areas

How are association areas different from sensory and motor areas?

They cannot be neatly mapped; not all in one place

What do association areas in the frontal lobes enable?

Judgment, planning, and processing of new memories

What happens if there is frontal lobe damage?

altered personality and remove inhibitions

What other mental functions are accomplished through association areas?

The parietal lobes - mathematical and spatial reasoning

Underside of right temporal lobe - help us recognize faces

area of the frontal lobe, usually in the left hemisphere, directs muscle movement involved in speech, helps control language expression.

Broca’s area

an area in the left temporal lobe involved in language expression and comprehension

Wernicke’s area

The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.

Plasticity

When is plasticity strongest?

childhood

__________ is what makes the brain unique.

Plasticity