Brain And Behavior Midterm 1

Front 1

Peripheral Nervous System
is made up of:
Function:

Back 1

spinal nerves, cranial nerves, autonomic nervous system

function: carries info into and out of CNS

Front 2

spinal nerves (also called somatic nerves)
dorsal and ventral roots

Back 2

(PNS) 31 pairs bring in sensory info and motor signals to and from the CNS

each spinal nerve has a dorsal (back) root: brings in sensory info
ventral (front) root: sends motor controls out

Front 3

cranial nerves
List 12 pairs. Sensory, motor, or both?

Back 3

(PNS) directly connected to brain's medulla
12 pairs:
I. olfactory: (Sensory) smell
II. optic (S) vision
III. oculomotor (Motor) moves eyes
IV. trochlear (M) moves eyes
V. trigeminal (S,M) face/sinuses/teeth, moves jaw muscles
VI. abducens (M) moves eyes
VII. facial (S,M) tongue, moves facial muscles/salivary glands/tear glands
VIII. vestibulochlear: (S) inner ear with auditory and balance functions
IX. glosspharyngeal: (S,M) taste, moves throat muscles
X. vagus: (S, M) info from internal organs (involuntary movement)
XI. spinal accessory: (M) neck and shoulders
XII. hypoglossal: (M) tongue

Front 4

autonomic nervous system
sympathetic, parasympathetic

Back 4

(PNS) controls the internal organs (involuntary)
sympathetic: "fight or flight" weekday system, hearing "pop quiz"
parasympathetic: "rest and digest" weekend system

Front 5

central nervous system

Back 5

brain and spinal cord
mediates all sensory inputs and motor outputs, generates behavior

Front 6

anatomical directions: anterior, posterior, dorsal, ventral, medial, lateral

Back 6

anterior (rostral): towards front
posterior (caudal): towards back

dorsal: top
ventral: bottom

medial: in the middle
lateral: on the outsides

Front 7

lobes of the cerebral hemisphere

Back 7

frontal lobe: executive functions, retain long term memory
parietal lobe: spatial functions
temporal lobe: primary auditory cortex, high level vision and memory
occipital lobe: primary visual cortex, fine motor skills

Front 8

outer surface of brain (CORTEX): gyri and sulci

Back 8

gyri: bumps/top parts of folds
sulci: infolds

Front 9

corpus callosum

Back 9

2 cerebral hemisphere connected by fiber bridges. They allow communication between the right and left hemispheres

Front 10

medulla, pons, hypothalamus, thalamus, hippocampus, fornix, pituitary gland, cerebellum, superior/inferior colliculus

Back 10

be able to identify on images!
hippocampus and fornix: learning (limbic system)
thalamus: all sensory info enters thalamus, where neurons send that info to the cortex
hypothalamus: hunger, thirst, temperature regulation, reproduction drive...controls pituitary gland: controls almost all hormone secretion

Front 11

meninges

Back 11

protective sheets of tissue that surround the brain and spinal cord
1. dura mater (outermost, hard)
2. arachnoid mater (spiderweb like, between dura and pia)
3. pia mater (innermost, soft)

Front 12

cerebral spinal fluid (CSF) and ventricular system

Back 12

CSF: waterbed protections comes from middle of tube that evolved into little holes called ventricles
medium for exchange between blood vessels and brain tissue

Front 13

choroid plexus

Back 13

lateral ventricles line with choroid plexus makes CSF in ventricles

Front 14

Ramon Y Cajal

Back 14

father of neuroscience
using Golgi stains, Cajal pieced together neural tissues to see how neurons are arranged (his drawings)

Front 15

Camillo Golgi

Back 15

developed Golgi staining technique: visualization approach that stains axons and dendrites
stains only a few cells
used to characterize the variety of cells in a region

Front 16

Neuron doctrine

Back 16

Cajal
neurons are independent functional and physiological units in the brain (extension of the cell theory: every structure is made up of cells)

Front 17

Reticular Theory

Back 17

(Golgi)
neurons are linked by anastomosis (continuity)

Front 18

Light microscopy vs. electron microscopy

Back 18

resolution of the light miscoscope could not resolve this debate, because resolution was too low- could not figure it out definatively.
electron microscopy able to see a physical space between the axon terminal on one hand and the head of the spine on the other --> Cajal was right!!!

Front 19

law of dynamic polarization

Back 19

Cajal
info flows from dendrites, through cell body, down axon

Front 20

principle of connectional specificity

Back 20

Cajal
no cytoplasmic continuity between nerve cells
they don't form random networks
each cell forms specific connections making contact with some nerve cells and not others

Front 21

axon hillock

Back 21

integrates inputs
"decides" output

where action potential generates

Front 22

axons

Back 22

usually 1 per cell
carries output from cell
transports chemicals from cell body to terminals
transmits electrical impulses to terminals (speed determined by size, myelin coating)

Front 23

dendrites

Back 23

many per cell
receives input signals
no myelin

Front 24

axon terminals

Back 24

many per cell
output transmitted to other cells

Front 25

3 common types of neurons

Back 25

1. monopolar neurons: transmits touch info from body to spinal cord; one axon branches 2 directions
2. bipolar neuron: common in sensory systems; one dendrite one axon
3. multipolar neuron: most common in cortex; many dendrites one axon

Front 26

Nissl stains

Back 26

see density of cell bodies in particular regions (ex. we see big cell bodies in motor cortex bc they need to go the distance down long axons)
can also stain for neurotransmitters

Front 27

cytoarchitectonics

Back 27

study of cell body cytoarchitecture in the cortex (using Nissl stains)

Front 28

chemoarchitectonics

Back 28

stains of neurotransmitters, hormones to differentiate the brain

Front 29

myloarchitectonics

Back 29

stains the density of the fiber bundles in the cortex

Front 30

glia

Back 30

in cortex, glia outnumber neurons 10:1 (opposite in cerebellum)

Communicate with each other and with neurons
Provide raw materials and chemical signals
Protection and damage control
Debris removal

Front 31

4 major glia

Back 31

Astrocytes: nourish & support with nutrients (ex. increasing bloog flow in a certain cappilary), scavenge extra neurotransmitters at synapse
Microglia: multiply at injury site, seal area, remove debris
Oligodendrocytes: make myelin (insulation around axons) in the CNS
Schwann cells: make myelin in PNS

Front 32

multiple scelorosis

Back 32

"many scars"
denegration of myelin
trouble moving muscles

Front 33

myelin sheath

Back 33

fatty insulation around axons that speeds conduction, protects axons
wraps around axons in layers--white matter

Front 34

Nodes of Ranvier

Back 34

gaps between segments of myelin
axon membrane is exposed

Front 35

What defines a brain area?

Back 35

1. Anatomical organization (cytoarchitectonics, myeloarchitectonics and chemoarchitectonics).
2. It’s Connections with other brain areas (Anatomical connections)
3. It’s Function (Physiology studies and lesion studies)

Front 36

anterograde tracers

Back 36

label axon terminals of cell bodies that take up the tracer (staining where cell bodies went)
inject in cortex (Where do these inputs project? Inject anterograde in different cortices.)

Front 37

retrograde tracers

Back 37

label cell bodies of the axon terminals that take up the tracer
inject in area X (What are all the inputs to area X? Inject retrograde in X)

Front 38

anatomical tool box

Back 38

Golgi stain
Nissl Stain
Chemical stain
Myelin stain
Anterograde tracers
Retrograde tracers

Front 39

Two types of communication happen in neurons

Back 39

electrical: within the neurons (from dendrite to axon)
chemical: between the neurons (transmission at the synapse)

Front 40

Ions:
anions, cations

Back 40

anions: negative charged ions
cations: positively charged

ions are dissolved in intracellular fluid (cytoplasm), separated from the extracellular fluid by the cell membrane

Front 41

resting membrane potential

Back 41

-50 to -90 mV
shows negative polarity of cell's interior
resting potential is a balancing act between diffusion and electrostatic pressure that drive K+ in and out of cell

Front 42

lipid bilayer

Back 42

cell membrane is a lipid bilayer: two layers of lipid molecules within which many special proteins float

Front 43

(gated) ion channels

Back 43

ion channels: proteins that span the membrane and allow ions to pass
gated ion channels: respond to voltage changes, chemicals, mechanical actions

Front 44

selective permeability

Back 44

allows some substances to pass but not others
potassium ions can enter/exit freely

Front 45

diffusion

Back 45

ions flow from high to low concentration, along concentration gradient (crystal light)

Front 46

electrostatic pressure

Back 46

ions flow towards oppositely charged areas (fridge magnets)

Front 47

sodium potassium pump

Back 47

lots of negative proteins inside cell that cannot get past membrane, making inside of cell negative (and attracting outside K+)
Pump maintains resting potential
It pumps three sodium ions (Na+) out for every two K+ ions pumped in.

Front 48

equilibrium

Back 48

when inside is -60 mV

pump causes a buildup of K+ inside. but bc of permeable membrane and diffusion, K+ will leave the inside and cause buildup of negative charge inside.
now, electrostatic pressure will pull K+ back inside.

equilibrium when any movement of K+ into the cell (by electrostatic pressure) matched by flow of K+ out of cell (by diffusion)

Front 49

Nernst equation

Back 49

predicts voltage needed to counterbalance diffusion force pushing an ion across membrane
This prediction is the resting membrane potential for that ion.

equilibrium potential = +40 mV

Front 50

Hodgkin and Huxley

Back 50

measured resting membrane potential of a living neuron (from giant squid axon)

They showed that the action potential was created by the movement of sodium ions into the cell through channels in the membrane

Front 51

hyperpolarization

Back 51

interior becomes more negative/increase in membrane potential

A hyperpolarizing stimulus produces a response that passively follows the stimulus.
The greater the stimulus the greater the response–the change in potential is called a graded response.

Front 52

depolarization

Back 52

interior becomes less negative/decrease in membrane potential

A depolarizing stimulus is the same as a hyperpolarizing one, to a point.....
If the membrane reaches the threshold–about –40 mV–it triggers an action potential.
The membrane potential reverses and the inside of the cell becomes positive.

Front 53

local potential

Back 53

as potential spreads, diminishes as it moves away from stimulus

Front 54

action potential

Back 54

(spike)

brief but large reversal of the membrane potential that momentarily makes inside of the membrane positive

originates at the axon hillock

Front 55

action potential threshold

Back 55

stimulus intensity just enough to trigger action potential at the axon hillock

Front 56

all or none property of action potentials

Back 56

fire at full amplitude or not at all (flushing)

opposite of graded responses

Front 57

afterpotentials

Back 57

positive or negative change following action potential

Front 58

voltage gated Na+ channel

Back 58

open when depolarization reaches threshold (at -40 mV)
and close when membrane potential reaches +40 mV

Front 59

voltage gated K+ channel

Back 59

open as inside of cell becomes more positive
K+ moves out and the resting potential is restored

Front 60

refractory period
absolute refractory phase
relative refractory phase

Back 60

Refractory period–only some stimuli can produce an action potential
Absolute refractory phase–no action potentials are produced
Relative refractory phase–only strong stimulation can produce an action potential

Front 61

conduction velocity

Back 61

speed of propagation of action potentials (determined by diameter of axon, thicker=faster)

Front 62

saltatory conduction

Back 62

action potentials jump from one node of Ranvier to the next because of myelinated axons

Front 63

excitatory post synaptic potential

Back 63

produces small local depolarization
pushes cell closer to threshold
caused by opening Na+ channels

Front 64

inhibitory post synaptic potential

Back 64

produces small hyperpolarization
pushes cell farther from threshold
caused by opening Cl- channels

Front 65

Charles Sherrington

spatial summation
temporal summation

Back 65

spatial summation: summing of potentials that come from different axon terminals
If the overall sum–of EPSPs and IPSPs–can depolarize the cell at the axon hillock, an action potential will occur.

temporal summation: summing of potentials that arrive at the axon hillock at different times
The closer together in time that they arrive, the greater the summation and possibility of an action potential.

Front 66

Loewi and Vagustoff

Back 66

chemicals are required for synaptic transmission

Stimulation of vagus nerve slowed the
heart of a frog. Placing fresh heart into same
solution slowed second heart without stimulation.

Deduced that stimulation of vagus released chemical into solution containing original frog

Front 67

calcium ions Ca+2 and voltage gated calcium channels

Back 67

The sequence of transmission:
1. Action potential travels down the axon to the axon terminal.
2. Voltage-gated calcium channels open and calcium ions (Ca2+) enter.
3. Ca2+ entry causes synaptic vesicles fuse with membrane and release transmitter into the synaptic cleft

Front 68

ligands

endogenous ligands
exogenous ligands

Back 68

anything that binds to a receptor-could activate or block
endogenous: neurotransmitters/hormones
exogenous: drugs and toxins from outside the body

Front 69

Acetylcholine (ACh) and its two types of receptors

Back 69

can be excitatory (open Na+, K+ channels) or inhibitory (open Cl- channels)

motor functions (heart and muscles), learning, and memory--Alzheimers

Nicotinic: most are ionotropic and excitatory
(Ex. muscles use nicotinic ACh receptors–paralysis can be induced with an antagonist)
Muscarinic–metabotropic and can be excitatory or inhibitory

Front 70

agonist vs. antagonist

Back 70

agonist: molecules that act like the transmitter at a receptor
antagonist: molecules that interfere/prevent action of a transmitter at its receptor

Front 71

iontropic vs. metabotropic receptors

Back 71

iontropic receptors: open when bound by a transmitter (ligand gated ion channel) (faster than metabotropic)

metabotropic: (no direct ion channel activity) first recognizes transmitter but instead activated G proteins
G proteins, or first messengers, sometimes open channels or may activate another chemical to affect ion channels.
The chemical is known as the second messenger–it amplifies the effects of the G protein and may lead to changes in membrane potential.

Front 72

degradation and reuptake

Back 72

synapses inactivated briefly:

degradation: chemical breakdown of a neurotransmitter
reuptake: released transmitter molecules are taken up and reused by the presynaptic neuron, thus stopping synaptic activity

Front 73

what defines a neurotransmitter

Back 73

Exists in pre-synaptic axon terminals
Substance is released when AP reach terminals
Specific receptors recognize the substance
Application of the substance produces changes in postsynaptic potential
Blocking release of the substance prevents nerve impulses

Front 74

glutamate

Back 74

major excitatory neutransmitter
uses AMPA and NMDA receptors (all ionotropic)

There are also metabotropic glutamate receptors as well

Front 75

GABA and glycine

Back 75

major inhibitory neurotransmitters

GABA A–ionotropic, producing fast, inhibitory effects via a Cl- channel (ALCOHOL)

Front 76

dopamine

Back 76

found in
mesostriatal pathway: originates in the midbrain, specifically the substantia nigra, and innervates the striatum
important in motor control and neuronal loss (separate from reward system) (parkinson's)
mesolimbocortical pathway (ventral tegmental area VTA): originates in midbrain, projects to limbic system and cortex (involved with reward, reinforcement learning) (schizophrenia, addiction)

Front 77

serotonin

Back 77

found in raphe nucleus
sleep, mood, sexual behavior, and anxiety

Prozac increases serotonin

Front 78

drugs

Back 78

act via neurotransmitter systems

many drugs are exogenous ligands
can be agonists or antagonists
can mess with your receptors

Front 79

binding affinity and efficacy

Back 79

binding affinity: chemical attraction between a ligand and a receptor
efficacy (or intrinsic activity): ability of a bound ligand to activate the receptor

Front 80

limbic system

Back 80

involved in emotion and learning
amygdala (almond shaped head of seahorse), hippocampus, fornix (tail of the seahorse)