PSY260 - 2. Neuroanatomy/Neurotransmission

Question 1

Tolman’s Maze

Answer 1

rat explores maze at will, eventually will follow route without error
will find a different route if preferred route blocked

Question 2

Tolman’s Maze

Answer 2

rat retains cognitive map to make it nonrandom search if changed
retains info it doesn’t know it’s going to need
blank slate isn’t blank, holds info that isn’t perceivable

Question 3

NEUROBIOLOGY

Hodgkin and Huxley (1939, 1945)

Answer 3

look inside neurons

organisms made up of cells + nervous systems made up of neurons

Question 4

NEUROBIOLOGY

Hodgkin and Huxley (1939, 1945)

Answer 4

putting wires on axons of squids
first measured action potential in neuron
action potential forms basis of neuronal activity

Question 5

MOLECULAR BIOLOGY Watson and Crick (1953) Franklin (1953)

Answer 5

DNA model

Question 6

Santiago Ramon y Cajal neuron theory

Answer 6

anatomist
notion of units in brain that formed structure
active participants in learning, but no knowledge of how they work

Question 7

How do neurons transmit and store information?

Answer 7

billions of neurons working

learning relies on coordinated action of multiple neurons

Question 8

Neuron

Answer 8

dendrite receives info ⇒ nucleus - integrates into single signal ⇒ axon - action potential ⇒ released to terminal buttons
in diff configurations - multiple connections to other neurons

Question 9

Mechanisms of Neurons

Answer 9

A: Creating + maintaining potential difference across the cell membrane (membrane potential, Vm)
B: Generating a signal down axon(action potential)
C: Receiving an input signal
D: Transmitting the signal to a target
E: Synaptic plasticity

Question 10

axon model

Answer 10

cell membrane made of lipid bilayer: porous tube separating inside of cell
diff ions can be accumulated creating diff environ than outside
structural protein makes it stronger
ion selective channels for K + Na

Question 11

Simple diffusion

Answer 11

probability of moving across based on concentration of ion inside compared to outside
inside + outside will equilibrate
2 ions work independently if only diffusion is working

Question 12

Axons - Action Potential

Answer 12

ions have charge
channels made differentially permeable
reds can move more easily, then more likely to move to balance negative charge out
built on propensity to diffuse

Question 13

Pumps

Answer 13

pumps increase diff inside
pressure to move based on differential permeability maintains gradient difference
works to change differential permeability
at rest, lots of K inside, pressure to move out
positive pressure of Na to move inside

Question 14

Membrane Current

Answer 14

demonstrates electrical potential that can be measured
potassium can’t come out if there’s an electrical force keeping it in
electrical forces in the cell that keep sodium outside

Question 15

ion concentrations

Answer 15

1. Membrane separates molecules inside from outside with the exception of small ion-specific pores.
2. Negatively charged molecules inside (only) balanced by positively charged ions

Question 16

ion concentrations

Answer 16

3. Potassium moves more easily, so is concentrated inside
4. Sodium is kept out by electrostatic charge.
5. Sodium-potassium pump maintains the gradients.

Question 17

Nernst Equation

Answer 17

V at equilibrium = potential to move out - potential to move in
C = concentration
balanced by electrical charges on right side

Question 18

Goldman-Hodgkin-Katz Equation

Answer 18

integrates diff pressures of multiple ions
will equal total membrane pressures
potassium bigger on inside, Na bigger on outside
Na wants to move in, but opposed by electrostatic charges

Question 19

Action Potential

Answer 19

Action potential form because the ion channels are sensitive to voltage.
At rest, most ion channels closed except K channel - leak current at negative membrane potentials: membrane potential will remain strongly negative
potential less negative = other channels may open
actions don’t actually have to move, just be there to push out

Question 20

Action Potential

Answer 20

membrane potential rises to about -40 mV, sodium channels open: providing an inward potential
positive feedback effect + rapid depolarization

Question 21

Simple action potentials

Answer 21

first open Na channels - potential to move in increases ⇒ depolarized - positive inside ⇒ Na close, open K channels to repolarize - outside positive, inside negative
pumps return Na outside + K inside during refractory period

Question 22

Simple action potentials

Answer 22

Near the peak of the action potential, other voltage dependent potassium channels open and contribute to further outward currents. At the same time sodium channels close + membrane returns to its negative potential

Question 23

Action potential propagation

Answer 23

1. Na potential increase causing nearby channels to do same
   Nearby affected + next region is affected
   Schwann cells: insulator around axons - directs currents along axon rather than through adjacent regions
   accelerates transmission of the signal down axon

Question 24

Action potential propagation

Answer 24

now negative outside causes depolarization to propagate along axis
Loss of myelin results in slower transmission speed + poor regulation of transmission timing = disorganized brain activity and loss of control ⇒ multiple sclerosis

Question 25

synapse

Answer 25

gap, where chem signals dropped into
neuronal communication: Ca causes movements of synaptic vesicles containing neurotransmitters
neurotransmitters moves to synapse + interacts with postsynaptic receptors

Question 26

Synaptic function

Answer 26

regulatory site: allows signals to be regulated

allows for modification in treatment of action potentials by sensitizing

Question 27

General principles of neuronal organization in the brain

Answer 27

• Neuronal activity similar in all cells

* Neuron structure reflects its functional role in info processing

Question 28

General principles of neuronal organization in the brain

Answer 28

• Synaptic contacts - sites for regulation + integration

* Modifications of synapse # + strength (growth + retraction of neurites) = plasticity, neural correlate of memory

Question 29

General principles of neuronal organization in the brain

Answer 29

• Learning ⇒ relatively permanent changes in synaptic connectivity underlying memory
• Flexibility, capacity, + capability increase with # of neuron
• Folding increases density of neurons in brains

Question 30

General principles of neuronal organization in the brain

Answer 30

•Distance counts: Brain regions specialized into centres with defined functions.
Regional activity accompanied by changes in blood flow
closer regions can communicate faster with one another
conservative design to neurons, fastest possible way to get signal transmtted

Question 31

General principles of neuronal organization in the brain

Answer 31

•Timing critical to learning + plastic changes
some cells have lots of connections + integrate a mass of input
not everything causes synapse to change same way

Question 32

Computed tomography [CT]

Answer 32

scan from multiple x-ray images at multiple angles ⇒ computer integrate, generating images that look like cross-sections through body

Question 33

Magnetic resonance imaging [MRI]

Answer 33

changes in magnetic fields generate images of internal structure
•Powerful magnets
radio waves broadcast, disturb atoms⇒Generate tiny electrical currents
•radio waves stop, return to stable align state
•Computer collects all signals and use them to generate images

Question 34

Primary motor cortex [M1]

Answer 34

generates coordinated movements - frontal lobe, adjacent to S1 in parietal lobe
•sends output to brainstem ⇒ send instructions down spinal cord to activate motor fibers that control muscles
•input from frontal lobe - high-level plans based on present situation, past experience + future goals
•Complex motor movements requires choreographed interactions betw frontal lobe, basal ganglia + brainstem + muscles

Question 35

Neuropsychology

Answer 35

deals with relation betw brain functions + behavior, examining functioning of patients with specific types of brain damage

Question 36

Engram

Answer 36

supposed physical change in brain that forms basis of a memory

Question 37

Theory of equipotentiality

Answer 37

memories not stored in one area of the brain, rather brain operates as a whole to store memories

Question 38

Positron a mission tomography [PET]

Answer 38

measures brain activity by detecting radiation from emission of subatomic particles called positrons, associated with brains use of glucose from the blood

Question 39

Functional magnetic resonance imaging [fMRI]

Answer 39

oxygenated blood produces slightly diff signals betw deoxygenated blood, fluctuations in signal received from areas of the brain that undergo change in activity level
•Tend to emphasize associations between specific brain regions and particular functions
•Both are comparatively slow

Question 40

Electroencephalography [EEG]

Answer 40

technique for measuring electrical activity in brain
•Electrodes record changes in electrical activity, measure combined tiny electrical charges of lots of neurons in brain
•Event related potential: average across many repetitions of the same event
oSimple and cheap way to monitor changes in brain activity, can detect rapid changes in brain with more precision, signal show activity over a wide swath of the brain (not location precise)