Unit 3 - Biological Bases of Behavior (Psychology)

Biological Psychologists

People who study the links between biological activity and psychological events

Biopsychosocial Systems

Systems composed of subsystems and in term are composed oof even smaller subsystems

Neuron

A nerve cell; the basic building block of the nervous system

What are the various parts of a neuron?

Cell body, dendrite, axon, myelin sheath

Cell body

The cell's life-support center

Dendrite

A neuron's bush; branching extensions that receive messages and conduct impulses toward the cell body

Axon

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

Myelin sheath

A fatty tissue layer segmentally encasing the axons; enables greater transmission speed

Multiple Sclerosis

When the myelin sheath degenerates. Communication with muscles slow and will eventually lose control of the muscles

Glial cells

Provide supporting functions to the nervous system

Action potential

A brief electrical charge that travels down the axon

What events allow neurons to fire?

1) Neuron stimulation causes a brief change in electrical change
2) If the electrical charge is strong enough, this produces depolarization and an action potential
3) Ions are exchanged -- the fluid outside an axon's membrane is mostly positively charged ions and the interior is negatively charged ions (resting potential)

How do security parameters change when a neuron fires?

1) The first section of the axon opens its gates
2) Positively charged sodium ions flood through the cell membrane
3) Axon section depolarizes and causes another axon channel to open up
4) During the refractory period (a period of inactivity after a neuron has fired), the neuron pumps positive sodium ions back outside to fire again

Excitatory signal

Signals that push a neuron's accelerator

Inhibitory signal

Signal that pushes the neuron's brakes

Threshold

The level of stimulation required to trigger a neural impulse

Refractory period

A period of inactivity after a neuron has fired

All-or-none response

A neuron's reaction of either (firing) with a full-strength response or not firing

Synapse (synaptic gap)

The junction between the sending axon's tip and the receiving neuron's dendrite or cell body.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons

How do neurotransmitters work?

When neurotransmitters are released, the neurotransmitter travels across the synapse and bind to receptor sites on the receiving neuron

Reuptake

The sending neuron reabsorbs the excess neurotransmitters

Acetylcholine (ACh)

Enables muscle action, learning, and memory (Alzheimer's disease)

Dopamine

Influences movement, learning, attention, and emotion (oversupply is linked to schizophrenia & undersupply is linked to Parkinson's)

Serotonin

Affects mood, hunger, sleep, and arousal (Undersupply is linked to depression)

Norepinephrine

Helps control alertness and arousal (Undersupply can depress mood)

GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter (undersupply linked to seizures, tremors, and insomnia)

Gulatmate

A major excitatory neurotransmitter; involved in memory (oversupply can overstimulate the brain -- migraines)

Endorphins

Natural, opiate-like neurotransmitter linked to pain control and pleasure

What happens when the brain is "flooded" with opiate drugs

The brain stops producing its own natural opiates. When the drugs are withdrawn, the brain may then be deprived of any form of opiate

Agonist

A molecule that binds to a receptor site and stimulates a response

Antagonist

A molecule that binds to a receptor site and inhibits or blocks a response (blocks a neurotransmitter's functioning)

Nervous system

The body's speedy, electrochemical communication network, consisting of the peripheral and central nervous systems

Central nervous system

The brain and spinal cord combined. The body's decision maker.

Peripheral nervous system

The sensory and motor neurons connected the central nervous system to the rest oof the body. Responsible for gathering information and transmitting CNS decisions to other body parts

Nerves

Electrical cables formed of bundles of axons that link the CNS with the body's sensory receptors, muscles, and glands

Sensory neurons (afferent)

Carry incoming information from the sensory receptors to the brain and spinal cord

Motor neurons (efferent)

Carry outgoing information from the brain and spinal cord to the muscles and glands.

Interneurons

Neurons within the brain and spinal cord communicate internally and intervene between sensory inputs and motor outputs

Somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system

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

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

Spinal cord

Two-way information highway connecting the peripheral nervous system and the brain. Ascending neural fibers send sensory information, and descending fibers send back motor-control infoormation

Reflexes

Automatic response to a sensory stimulus -- if the spinal cord is severed, you would not feel pain

Endocrine system

The body's slow chemical communication system (a set of glands that secrete hormones into the bloodstream)

Hormones

Chemical messengers manufactured by the endocrine glands that travel through the bloodstream and affect other tissues
Influence our interest in sex, food, and aggression

Adrenal glands

A pair of endocrine glands that sit above the kidneys and secrete hormones that help arouse the body

Pituitary gland

regulates growth and controls other endocrine glands

Lesion

Tissue destruction

How else can scientists observe brain functions?

electrically, chemically, or magnetically stimulate various parts of the brain and noting the effect.

electroencephalogram

amplified recording of the waves of electrical activity sweeping across the brain's surface - measured by electrodes placed on the scalp

magnetoencephalography

the measurement of the magnetic field generated by the electrical activity of neurons

CT (computed tomography) scan

a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain's structure; can reveal brain damage

PET (positron emission tomography) scan

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

MRI (magnetic resonance imaging)

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

fMRI (functional magnetic resonance imaging)

can reveal the brain's functioning as well as its structure

Brainstem

the oldest part of the central core, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival function

medulla

the base of the brainstem; controls heartbeat and breathing

reticular formation

inside the brainstem and between your ears; a neuron network that extends from the spinal cord right up through the thalamus. Plays an important role in controlling arousal.

thalamus

the brain's sensory control center, located on top of the brainstem it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

cerebellum

at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

pons

above the medulla and helps coordinate movements

Limbic system

Neural system that includes the hippocampus, amygdala, and hypothalaums. The limbic system is located below the cerebral hemispheres; associated with emotions and drives.

Amygdala

two lima-bean-sized neural clusters linked to aggression and fear. The amygdala also plays a role in the perception of processing of emotional memories.

hypothalamus

directs maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

hippocampus

processes conscious memories.

cerebrum

forms specialized work teams that enable our perceiving, thinking, and speaking.

cerebral cortex

covers the cerebral hemisphere, the body's ultimate control and information processing center.

frontal lobe

behind the forehead; involved in speaking and muscle movements and in making plans and judgments

parietal lobe

lies at the top of the head and toward the rear; receives sensory input for touch and body position

occipital lobe

lies at the back of the head; includes areas that receive information from the visual fields

temporal lobe

above the ears; includes the auditory areas, each receiving information primarily from the opposite ear

motor cortex

An area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

An area at the front of the parietal lobes registers and processes body touch and movement sensations. The somatosensory cortex receives incoming messages.

Association areas

areas of the cerebral cortex that are not involved in primary motor or sensory function; instead, are involved in higher mental functions

Broca's Area

The region of the brain concerned with the production of speech

Wernicke's Area

Concerned with the comprehension oof language

Plasticity

The brain's ability to change

Neurogenesis

The formation of new neuronal the brain sometimes mends itself by producing new brain cells

Lateralization

Our brain's look-alike left and right hemispheres serve different functions

Corpus callosum

Large band of neural fibers connecting the two brain hemispheres and carrying messages between them

Split brain

A condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers connecting them

What happens when the "two minds" are at odds?

When "two minds" are at odds, the left hemisphere does mental gymnastics to rationalize reactions it does not understand.

When is the left hemisphere more active? When is the right hemisphere more active?

When a person performs a perceptual task, the activity in the right hemisphere is increased. When the person speaks or calculates, activity increases in the left hemisphere.

right brain

excels in making inferences, helps us modulate our speech, and helps orchestrate our sense of self

left brain

process language

consciousness

Consciousness is our awareness of ourselves and our environment.

cognitive neuroscience

Cognitive neuroscience is the interdisciplinary study of the brain activity linked with our mental processes.

dual processing

The principle that information is often simultaneously processed on separate conscious and unconscious tracks.

blindsight

Blindsight is acting like you can see.

What do people often have trouble accepting?

Accepting that much of our everyday thinking, feeling, and acting operates outside our conscious awareness.

parallel processing

The processing of several aspects of a problem simultaneously.

sequential processing

Mental process of integrating and understanding stimuli in a particular order.

behavior genetics

The study of the relative power and limits of genetic and environmental influences on behavior.

Describe the influences of heredity and environment on our behavior

Heredity creates a framework within which the environment acts to shape the behavior of an individual animal.

chromosomes

Threadlike structures made of DNA molecules that contain the genes

DNA (deoxyribonucleic acid)

DNA is a complex molecule containing the genetic information that makes up the chromosomes

Genes

Biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins

Genomes

complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes