psych 230 exam 1

neuroscience

neuroscience

study of the nervous system

behavioral neuroscience

study of the biological bases of psychological processes and behavior

5 viewpoints to explore the biology of behavior

1. describing behavior

2. studying biological mechanisms of behavior

3. observing the development of behavior over a single life-span

4. studying the evolution of behavior over many life-spans

5. studying applications of neuroscience

somatic intervention

change the brain → check behavior

behavioral intervention

change behavior → check brain

correlation

how much a body measure varies with a behavioral measure

within-subjects experiment

control group = experimental group

between subjects experiement

separate control and experimental groups

non experimental types

• correlational

• survey/poll

• case-study

• longitudinal research

• historical/archival

• naturalistic observation

neuroplasticity

ability of the brain to be changed by the environment and experience

neuron doctrine

the brain is composed of independent cells that are distinct structurally, metabolically, and functionally

structures that neurons have in common with other cells

mitochondria, golgi apparatus, ribosomes

4 principal subdivisions of neurons

1. input zone

2. integration zone

3. conduction zone

4. output zone

input zone

neuronal cell body and dendrites receive info via synapses from other cells

integration zone

part of the neuron that initiates nerve electrical activity (axon hillock)

conduction zone

part of the neuron where the signal is sent through (axon)

output zone

where the neuron transfers info to other cells (axon terminal)

motorneurons

stimulate muscles and glands

sensory neurons

respond to environmental stimuli

interneurons

receive input from and send input to other neurons

glial cells

nonneuronal cells that provide structural, nutritional, and other types of support to the brain.

glial cells can…

1. communicate with each other and other neurons

2. provide raw materials

3. alter neural structure and excitability

astrocytes

start-shaped cells that receive neuronal input and monitor neural activity, monitor blood flow and help form new synapses and prune old one

unipolar neuron

have a single extension, usually thought of as an axon, that branches in two directions after leaving the cell body

bipolar neurons

A nerve cell that has a single dendrite at one end and a single axon at the other end

multipolar neurons

A nerve cell that has many dendrites and a single axon

microglia

house-keeping cells and the primary immune cells in the brain

oligodendrocytes

provide myelin in the CNS

schwann cells

provide myelin in the PNS

nodes of ranvier

gaps between sections of myelin where the axon is exposed + voltage-gated ion channels are located

gross anatomy

features of nervous system visible to the naked eye

central nervous system (CNS)

brain and spinal cord

peripheral nervous system

all parts outside of the brain and spinal column; nerves/bundles of axons,

motor nerves

transmit info from CNS to muscles, organs, and glands

sensory nerves

convey info from the body to the CNS

somatic ns

interconnect the brain and major muscles + sensory systems; cranial and spinal nerves

cranial nerves

a nerve that is connected directly to the brain

spinal nerves/somatic nerve

A nerve that emerges from the spinal cord

dorsal root

sends sensory info to the spinal cord

ventral root

sends info to the muscles

autonomic ns

the part of the peripheral nervous system that supplies neural connections to glands and to smooth muscles of internal organs

sympathetic ns

prepares for action; produces norepinephrine to accelerate activity

parasympathetic ns

returns the body to homeostasis; produces acetylcholine

enteric ns

regulates the functioning of the gut; maintains fluid and nutrient balances

cerebral cortex

thick outermost layer of the brain comprised of cell bodies, dendrites and axons

gyrus

raised parts

sulci

furrows/indentations

gray matter

cell bodies

white matter

axon tracts

4 lobes of the brain

1. frontal

2. parietal

3. temporal

4. occipital

cortical columns

perpendicular to the cortical layers and serve as a unit to process info

cerebellum

motor learning and coordination

purkinje cell layer

middle layer of cerebellum, large cells form a row

granule cell layer

small neurons whose axons form the third innermost layer of the cerebellum

parallel layer

outermost layer of cerebellum

dura mater

tough outermost layer of brain

pia mater

delicate innermost layer of brain

arachnoid

substance between dura mater and pia mater that cushions the brain in cerebral spinal fluid

ventricular system

chambers filled with csf

functions of csf

1. shock absorber

2. provides exchange medium between the blood and brain to provide both fluid and nutrients to the brain

lateral ventricle

extends into all 4 lobes and is lined with the choroid plexus (produces csf)

3rd and 4th ventricle

csf flows into 3rd ventricle at midline then the 4th ventricle and exits to circulate over the brain and spinal cord

vascular system

provides the brain with oxygen

blood-brain barrier

result of higher resistance in brain capillaries that restricts the passage of large molecules

3 parts of synapse

presynaptic membrane, synaptic cleft, postsynaptic membrane

post synaptic receptors

specialized proteins that react when a nt binds to them

axon hillock

cone-shaped area of cell body that gives rise to axon; site of integration

axonal transport

movement of materials within an axon via motor proteins

neurophysiology

study of electrical and chemical processes in neurons; info flows within a neuron using chemical signals and between neurons using chemical signals

resting membrane potential

-65mV

maintaining membrane potential

1. selectively permeable ion channels

2. electrostatic forces

3. sodium-potassium pump

sodium potassium pump

• pumps three sodium ions out for every two potassium ions in

action potential

cell firing; how one cell sends a message to another cell

hyperpolarization

making the membrane potential of a neuron decrease by increasing the negative charge on the inside

depolarization

making the membrane potential increase

action potential sequence

1. when the threshold for activation is triggered an action potential begins

2. voltage-gated sodium channels open

3. sodium ion rush into cell until mp is +40mV

4. as inside of cell becomes more positive, voltage-gated K+ channels open

5. K+ move out and resting potential is restored

6. happens all the way down the axon

afterpotential

when potassium channels close slowly so, too many potassium ions leave the cell, and it becomes more negative

refractory period

time when only some stimuli can produce an action potential

absolute refractory phase

time when no new action potentials can be produced

relative refraction phase

time when only strong stimuli can produce an action potential

how is the ap propagated along the axon

an ap is a spike of depolarizing electrical activity, so it strongly depolarizes the next adjacent axon segment and opens the voltage-gated sodium channels to produce another electrical spike

conduction velocity

speed of propagation of action potentials varies with diameter

saltatory conduction

the axon potential travels inside the axon and jumps from node to node

demyelinating disorder

when the body’s immune system produces antibodies that attack myelin and conduction of action potentials

first step of nt transmission

action potential travels down axon to axon terminals

second step of nt transmission

voltage-gated calcium channels open at the axon terminals and cause influx of calcium ions

third step of nt transmission

exocytosis

exocytosis

calcium ions cause vesicles filled with nts to fuse with the presynaptic membrane and release their contents into the synaptic cleft

v-SNARE

specialized protein anchored to vesicles to aid their fusing to the presynaptic membrane to release neurotransmitter

t-SNARE

specialized protein anchored to the presynaptic “target” membrane to bind v-SNAREs to dock vesicles, making them ready for release

synaptotagmin

a specialized protein that responds to calcium ions to trigger vesicular exocytosis

fourth step of nt transmission

the nts cross the synaptic cleft and bind to special receptors on the postsynaptic cell where they cause small changes in membrane potential of the post synaptic cell

fifth step of nt transmission

the nts diffuse away and are broken down by enzymes or are taken back up to the presynaptic cell

tetrodotoxin (TTX) and saxitoxin (STX)

block voltage gated sodium channels

Batrachotoxin

force sodium channels to stay open

botulinum (botox) and tetanus toxin

inhibit neural transmission by cutting up SNARE proteins and stopping exocytosis

postsynaptic potentials

nts bind to receptors on the postsynaptic cell and briefly alter membrane potential of postsynaptic cell

excitatory postsynaptic potentials (EPSPs)

certain nt (glutamate) binds and lets positive ions into the cell; makes membrane potential more positive (depolarization) and increases likelihood of firing

inhibitory postynaptic potentials (IPSPs)

certain nt (GABA) binds and lets negative ions into the cell; makes membrane potential more negative (hyperpolarization); decreases likelihood of firing

local PSP

the change in membrane potential spreads passively over the neuron and degrades in strength over time and distance