BIOLOGICAL BASES OF BEHAVIOR

Gall's theory of phrenology

Gall's theory of phrenology

theorized that studying the bumps on a human skull could reveal a person's mental abilities and character traits--> proved localization of function

localization of function

various brain regions have particular functions

biological psychology

Studies the links between biological (genetic, neural, hormonal), and psychological processes

neurons

a nerve cell; the basic building block of the nervous system. BASIS OF THE NERVOUS SYSTEM

dendrite

a neuron's bushy, branch extensions that RECEIVES MESSAGES and conduct impulses toward the body.

axon

the extension of a neuron that PASSES MESSAGES through its branches to other neurons, muscles, or glands

myelin sheath

layer of fatty tissue that covers many axons and helps speed neural impulses

myelin sheath deterioration

--> multiple sclerosis: communication to muscle slows then eventually loses complete muscle control

action potential

a neural impulse; a brief electrical charge that travels down an axon

ions

electrically charged atoms that are exchanged in the neuron's chemistry-to-electricity process

resting potential

positive-outside/negative-inside state of an axon membrane

selectively permeable

axon membranes only allows certain substances to pass through

depolarize

when a neuron fires, the first section of the axon opens its gates, and positively charged sodium ions flood through the cell membrane→ Another axon's channels open, and another and another

refractory period

a period of inactivity after a neuron has fired

excitatory signal

excite and stimulate neuron and causes it to fire off a message

inhibitory signal

pushing a neuron's brake and prevents it from firing

threshold

the level of stimulation required to trigger a neural impulse

all-or-none response

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

synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Santigo y Cajal "protoplasmic kiss"

refers to the transmission of neurotransmitters across the synapse between the terminal branches of one neuron and the dendrites of another

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

reuptake

a neurotransmitter's reabsorption by the sending neuron

dopamine

neurotransmitter than influences movement, learning, attention, and emotion

serotonin

neurotransmitter that effects mood, hunger, sleep, and arousal

norepinephrine

neurotransmitter that helps control alertness and arousal

GABA

a major inhibitory neurotransmitter

glutamate

A major excitatory neurotransmitter; involved in memory

endorphins

"morphine within"--natural, opiate-like neurotransmitters linked to pain control and to pleasure (e.g. runner's high)

agonist

a molecule that, by binding to a receptor site, stimulates a response. MIMICS

antagonists

A molecule that, by binding to a receptor site, inhibits or BLOCKS a response

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the PERIPHERAL and CENTRAL nervous systems

central nervous system (CNS)

the body's decision maker, the brain and spinal cord

peripheral nervous system (PNS)

sensory and motor neurons responsible for gathering information and for transmitting CNS decisions to other body parts

nerves

electrical cables formed of bundles of axons that connect the CNS with muscles, glands, and sense organs

sensory (afferent) neurons

neurons that carry messages from the body's tissues and sensory receptors inward to the brain and spinal cord for processing 5 SENSES

motor (efferent) neurons

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands. MOVEMENT

interneurons

neurons within the CNS that communicate internally and intervene between the sensory inputs and motor outputs. INTERCEPTING NEURONS (REFLEX)

somatic nervous system

part of the peripheral nervous system that enables voluntary control of our skeletal muscles (aka the skeletal nervous system) VOLUNTARY

automatic nervous system (ANS)

controls our glands and the muscles of our internal organs, influencing such functions as glandular activity, heartbeat, and digestion AUTOMATIC

sympathetic nervous system

an important function of the ANS that arouses and expends energy.

sympathetic nervous system activates

fight or flight response

parasympathetic nervous system

a division of the ANS that calms the body when the stress subsides, conserving energy.

parasympathetic nervous system activates

rest and digest

neural network

Neurons cluster into work groups and network with nearby neurons with which they can have short, fast connections

reflex

interneurons will intercept motor and sensory neurons; automatic responses to stimuli

endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

hormones influence on the brain

interest in sex, food, and aggression

adrenal glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress- increase heart rate, blood pressure, and blood sugar→ fight or flight responses

pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

Early case studies of the brain found that damage to one side of the brain caused numbness or paralysis on the opposite side of the body. This suggested that:

body's right side is wired to the brain's left side, and vice versa

lesion

tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue

when doctors stimulate certain sections of the brain

people may giggle, hear voices, turn their head, feel themselves falling, have an out of body experience

Electrocephalogram (EEG)

measures electrical impulses in the brain, seeing what at what level your brain is functioning

computed tomography (CT)

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

Positron Emission Tomography (PET)

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

magnetic resonance imaging (MRI)

brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain

fMRI (functional MRI)

A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans

brainstem

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

medulla

the base of the brainstem; controls heartbeat and breathing

pons

right above the medulla where it helps coordinate movements

thalamus

A pair of egg-shaped structures that act as the brain's sensory switchboard. It receives information from all the senses except for smell and routes it to the higher brain regions that deal with all senses (except for smell) It also receives some of the higher brain's replies.

reticular formation

A nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal

cerebellum

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

limbic system

A neural system (including hippocampus, thalamus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives

emotions and motives linked to the limbic system

fear and anger, food and sex

hippocampus

processes conscious memories and forms the memory

Patient H.M

had hippocampus removed; showed that removing hippocampus destroyed the ability to form new memories

amygdala

two lima bean-sized neural clusters in the limbic system; linked to emotion. LINKED TO AGGRESSION, FEAR, AND ANXIETY

hypothalamus

a neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward

James Olds and Peter Milner

discovered a part of the hypothalamus that provides "reward centers"

reward centers

spots in the brain that stimulate pleasure

nucleus accumbens

another limbic reward center

Older brain networks sustain...

basic life functions, enable memory, emotions, basic drives (15%)

newer neural networks

within the cerebrum form specialized work teams that enable our perceiving, thinking, and speaking (85%)

cerebral cortex

It covers up the hemispheres: the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center

glial cells

cells in the nervous system that support, nourish, and protect neurons; they may also play a role in thinking and learning

parts of the cerebral cortex

frontal lobe, parietal lobe, occipital lobe, temporal lobe

frontal lobes

the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments

parietal lobes

portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position

occipital lobes

portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields

temporal lobes

portion of the cerebral cortex lying roughly 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

what happens when the motor cortex in the LEFT hemisphere is stimulated

Causes movements to specific body parts on the opposite (right) side of the body

cognitive neural prosthetics

those with paralyzed limbs may be able to use their brain signals to control computers and robotic limbs

somatosensory cortex

area at the front of the parietal lobes that registers and processes body touch and movement sensations

association areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking

prefrontal cortex

The forward part of the frontal lobes enables judgment, planning, and processing of new memories

Phineas Gage Case Study

Phineas Gage: railroad worker who survived a brain injury that changed his personality and behavior;

case study examined the localization of brain function: frontal lobe controls personality and behavior

prefrontal lobe function

judgment, planning, and processing of memories

frontal lobe function

personality and inhibitions

parietal lobes function

enable mathematical and spatial reasoning

the underside of the temporal lobe function

enables us to recognize faces

Broca's area function

necessary for the production and coordination of speech

Wernicke's area function

allows us to comprehend language, both written and spoken

auditory cortex location

temporal lobe, right by the ear

visual cortex location

occipital lobe, back of head

plasticity of the brain

the brain's ability to change, especially during childhood, by recognizing after damage or by building new pathways based on experience