Psych Unit 3

neuron

a nerve cell; basic building block of the nervous system

• purpose: to transmit a message

  • fires electronically —> must have a stimulus

  • fire in rapid succession

cell body

the part of a neuron that contains the nucleus; the cell’s life support center

dendrite

a neuron’s often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body

axon

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

myelin sheath

fatty tissue layer insulating and speeding up impulses of axons

glial cells (glue cells)

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

action potential

a neural impulse —> brief electrical charge traveling down an axon; basically the neuron “firing”

• opening the flap in the toilet tank and the water rushing through the pipes

threshold

point of excitation on the neuron that must be reached for an action potential to occur

• you can push the handle a little bit but a toilet won’t flush until you push the handle past a certain point

refractory period

brief resting pause that occurs after a neuron has fired; subsequent action potentials can’t occur until axon returns to its resting state; “recharging” time

• after you flush the toilet, it won’t flush again for a certain period, even if you push the handle

all-or-nothing response

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

• a toilet either flushes completely or not at all

synapse

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

reuptake

excess neurotransmitter reabsorbed by axon terminal of sending neuron

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

• when released by the sending neuron, they travel across the synapse and bind to receptor sites on the receiving neuron —> influences whether that neuron will generate a neural impulse

• electrically charge the next neuron; start a new action potential

agonist

a molecule increasing a neurotransmitter’s action

antagonist

a molecule inhibiting/blocking a neurotransmitter’s action

acetylcholine

a neurotransmitter that enables muscle action, learning, and memory

• malfunction: Alzheimer’s- ACh-producing neurons deteriorate

dopamine

a neurotransmitter that influences movement, learning, attention, and emotion

• oversupply —> schizophrenia

• undersupply —> tremors, decreased mobility with Parkinson’s

serotonin

a neurotransmitter that affects mood, hunger, sleep, and arousal

• undersupply —> depression

  • drugs that raise levels of it can treat depression

norepinephrine

a neurotransmitter that helps control alertness and arousal

• undersupply —> depressed mood

GABA

a major inhibitory neurotransmitter associated with relaxation

• undersupply —> seizures, tremors, insomnia

endorphins

a neurotransmitter that influences perception of pain or pleasure

• oversupply w/ opiates —> suppresses natural supply

epinephrine

a neurotransmitter that affects metabolism, attention, focus, panic, and excitement

• malfunction: sleep disorders, anxiety, hypertension, lowered immunity

biological psychologist

a psychologist focusing on how our body and mind are connected/interact —> how the brain works/its structure and chemicals

impulse

communication between neurons are chemical interactions that causes an electric reaction in the next neuron; always goes in same direction

• toilet water always goes down, not up

nervous system

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

• takes in info from the world/the body’s tissues, makes decisions, sends back info/orders

central nervous system

the brain and spinal cord

• the body’s decision maker

• info processing (main communication path for info)

• neural network

peripheral nervous system

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

• nerves'

• responsible for EVERYTHING

nerves

bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs

sensory neurons

neurons that carry incoming info from the body’s tissues and sensory receptors to the brain and spinal cord

motor neurons

neurons that carry outgoing info from the brain and spinal cord to the muscles and glands

interneurons

neurons within the brain and spinal cord

• communicate internally —> process info between the sensory inputs and motor outputs

somatic nervous system

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

• spinal nerves to skeletal muscles

• controls voluntary movements

autonomic nervous system

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

• nerves to internal organs and glands

• automatic functions (breathing, digestion)

• sympathetic and parasympathetic divisions

sympathetic nervous system

(part of autonomic nervous system) arousing effects (ex. fight or flight, racing heartbeat)

parasympathetic nervous system

(part of autonomic nervous system) calming effects (ex. slowing heartbeat)

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

• when they act on the brain, they influence our interest in sex, food, and aggression

• ex. melatonin, insulin

adrenal glands

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

• fight-flight-freeze response

pituitary gland

an endocrine gland that, under the influence of hypothalamus, regulates growth and controls other endocrine glands

• most influential endocrine gland!!

• “master” gland because it regulates release of hormones and controls other glands

  • releases growth hormones

pineal gland

an endocrine gland that makes the hormone melatonin —> helps the body control day-night sleep patterns and circadian rhythm

resting potential

when a neuron is “charged” and waiting for another impulse

• toilet after the water has filled up and can flush again

depolarization

when the action potential fires, channels along the axon allow NA+ and K+ channels to open, thus propelling the electrochemical process down the axon

receptor cells

info receptive cells that translate different kinds of energy into electric impulses (action potential)

hypothalamus

controls pituitary gland, regulates glucose blood levels by stimulating insulin release (by pancreas)

thyroid gland

controls energy levels by regulating metabolism

pancreas

endocrine organ

• behind stomach

• releases hormone insulin

• regulates blood sugar levels by breaking down glucose (body’s fuel)

testis

endocrine gland; releases male hormones (testosterone) responsible for development of male characteristics

ovary

endocrine gland; releases female hormones (estrogen) responsible for development of female characteristics

lesion

naturally or experimentally caused tissue destruction

EEG

amplified recording of the waves of electrical activity in neurons sweeping across the brain’s surface; measured by electrodes placed on the scalp

• used for imaging of function/activity

MEG

a brain imaging technique that measures magnetic fields from the brain’s natural electrical activity (ex. soldiers with PTSD have stronger magnetic fields when viewing training-related images)

• used for imaging of function/activity

CT

“fancy X-ray”; a series of X-ray photos taken from different angles and combined by the computer into a composite representation of a slice of the brain’s structure —> may indicate brain damage

• used for imaging of structure

PET

a brain imaging technique that detects where a radioactive form of glucose goes while the brain performs a given task (ex. monkeys with anxious temperament have brains that use more glucose in regions related to fear, memory, and expectations of reward/punishment)

• used for imaging of function/activity

MRI

a technique using brain scans and radio waves to produce computer-generated images of soft tissue; show brain anatomy

• used for imaging of structure

fMRI

a technique for revealing blood flow —> brain activity by comparing successive MRI scans

• shows brain structure AND function/activity

brainstem

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

medulla

the base of the brainstem (slight swelling of spinal cord just after it enters skull), controls heartbeat and breathing

• damage —> respiratory failure, paralysis, brain death

thalamus

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

• damage —> unconsciousness, sleep disorders, sensory breakdown (all senses but smell)

reticular formation

nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal, relays the info to other brain parts

• damage —> irreversible coma

cerebellum

the “little brain” at the rear of the brainstem; processes sensory input, coordinates voluntary movement output/balance, enables nonverbal learning/memory

• damage —> staggering, tremors, coordination loss

limbic system

neural system located below the cerebral hemispheres; associated with emotions and drives

amygdala

2 lima-bean-sized neural clusters in the limbic system; linked to emotion, aggression, and fear

• damage

  • removal: reduced arousal to fear

  • stimulation: aggression

hippocampus

in temporal lobe beneath front of thalamus; helps process for storage explicit (conscious) memories of facts/events

• damage —> loss of NEW short-term memories, retrograde or anterograde amnesia

plasticity

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

neurogenesis

the formation of new neurons

split brain

a condition resulting from surgery that isolates the brain’s 2 hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

consciousness

our subjective awareness of ourselves and our environment

• comes in many forms

• daydreaming, meditating

• sleep is a state of consciousness

cognitive neuroscience

the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language)

dual processing

information is often simultaneously processed on separate conscious/unconscious tracks

parallel processing

processing many aspects of a problem simultaneously; the brain’s natural mode of info processing for many functions

sequential processing

processing one aspect of a problem at a time; generally used to process new info or to solve difficult problems

pons

above medulla; a structure linking the brain (thalamus) to the spinal cord (medulla); a juncture point in motor and sensory info, coordinates movements, controls autonomic processes like sleep and circadian rhythms

• damage —> paralysis, locked-in syndrome

frontal lobes

behind forehead; involved with speech, muscle movement (motor cortex), making plans/judgments/problem solving

• damage —> difficulty making decisions/organizing, motor issues

parietal lobes

at top, rear of head; processes info and associations, receives sensory input for touch, body position (somatosensory cortex)

• damage —> sensation issues

occipital lobes

back of head; controls visual reception and interpretation

• damage —> blindness (or flashes of light, if slightly injured)

temporal lobes

above ears; auditory processing, language composition, memory/info retrieval

• damage —> deafness (or phantom ringing; overstimulated in schizophrenic auditory hallucinations)

motor cortex

rear of frontal lobes; controls voluntary movements

• damage —> coordination loss; stimulation→body part moved but no perception of it

somatosensory cortex

front of parietal lobes; registers, processes body touch and movement sensations

• damage —> numbness, tingling; stimulation→felt like body part moved but it didn’t

association areas

areas in all 4 lobes (cerebral cortex) not involved in primary motor/sensory functions; involved with higher mental functions, such as learning, remembering, speaking, and thinking

• damage —> inability to recognize/learn new faces

  • prefrontal cortex: removed inhibitions

  • parietal lobe: math and spacial reasoning

cerebral cortex

intricate fabric of interconnected neural cells covering cerebral hemispheres. the ultimate control and info processing center

corpus callosum

the large band of neural (axon) fibers connecting the 2 brain hemispheres; carries messages between them

• damage —> split brain

left hemisphere

language center, analytical/mathematical reasoning, home of Broca’s and Wernicke’s area

Broca’s area

left frontal lobe; directs muscle movement involved with expressing language (speech)

• damage —> disrupted speaking

Wernicke’s area

left temporal lobe; processes receptive language (ability to understand speech)

• damage —> disrupted understanding

right hemisphere

spatial reasoning, inferential skills, processing relationship of words (interpreting meaning)

aphasia

language impairment due to damage to the LEFT hemisphere (either in Broca’s area or Wernicke’s area)

behavior genetics

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

chromosome

threadlike structures made of DNA molecules that contain the genes

DNA

a complex molecule containing the genetic info that makes up chromosomes

genes

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

genome

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

heritability

the proportion of variation among individuals in a group that we can attribute to genes (may vary depending on the range of populations/environments studied)

molecular genetics

a subfield of biology that studies the molecular structure and function of genes

molecular behavior genetics

the study of how the structure and function of genes interact with our environment to influence behavior

epigenetics

the study of environmental influences on gene expression that occur without a DNA change

• our genetic code doesn’t get expressed the same way in all situations

• environmental conditions (epigenetic molecules, trauma, etc.) affect the expression of our genes

upstairs brain

does the thinking, conscious processing, judgment, planning

downstairs brain

does the feeling, especially anger and fear

circadian rhythm

our biological clock; regular bodily rhythms (ex. temperature, wakefulness) that occur on a 24-hour cycle

• brain shuts down “consciousness” during sleep

• lack of sleep —> harmful disruption to body’s natural rhythms

REM sleep

a recurring sleep stage when vivid dreams commonly occur; known as “paradoxical sleep” because the muscles are relaxed but other body systems are active

• (100 min total) FAST brain waves, 25% of sleep time

alpha waves

the relatively slow brain waves of a relaxed, awake state