Neur305 exam 1

Dr. Jose Delgado

was able to control bulls remotely through brain

does behavior control neural activity

no, neural activity controls behavior

astrocytes, oligodendrocytes, Schwann cells

glial cells

can glia communicate?

Yes, chemically

can an individual neuron receive multiple inputs?

yes

does neuron have same organelles as other cells

yes

where does synapse occur

Synaptic cleft
axon terminal of pre-synaptic cell - dendrite of post-synaptic cell

How does astrocyte help in synaptic communication

neural threesome
Regulate neurotransmitters within synapse

where is action potential initiated?

axon hillock

Resting Membrane potential

difference in voltage between inside and outside of neurons (-70 mV) separated by semipermeable lipid bilayer
Stored electrical charge
Regulated by sodium potassium pump

How does depolarization occur?

EPSP's add up to reach threshold

saltatory conduction

electrical signals of axons move only one way

what is glutamate released by?

pyramidal cells

what is the most abundant neurotransmitter

glutamate

neurotransmitter that is fast, excitatory

glutamate

second most prevelant neurotransmitter

GABA

what is GABA synthesized from

glutamate

neurotransmitter that is fast, inhibitory

GABA

producer of dopamine

Substantia nigra + ventral tegmental area

producer of norepinephrine

locus coeruleus

producer of serotonin

raphe nucleus

Encoding

stimulus -\> response

Decoding

response -\> stimulus

Rate Coding

rate at which the motor units are fired

Temporal coding

intervals/timing between action potentials

Rate coding

the NUMBER of action potentials

Coronal view

Horizontal/Traverse view

Sagittal view

Superior view

Inferior view

Lateral view

Microscopic level

single neurons and their synaptic connections

Mesoscopic level

connections within and between columns and other local cell assemblies

Macroscopic level

anatomically segregated brain regions

Anatomical (structural) connectivity

pattern of structural connections between neurons, neuronal populations, or brain regions

Functional connectivity

pattern of statistical dependencies between distinct (often remote) neuronal elements

effective connectivity

network of causal effects, combination of functional connectivity and structural model

Brain lesions tend to have effects on what scale

Macroscopic

What does traumatic brain injury cause?

Inflammation
Torn fibers (axons)

What are CT scans

Computerized axial tomography
Xray images from different angles to create 3D

is CT scan cheaper than MRI

Yes

MRI

magnetic resonance imaging

Does CT have higher resolution than MRI

No, MRI has better resolution

How does MRI work

1. Magnetic field aligns proteins
2. Radio waves applied, put protons in elevated energy state
3. Radio turned off, protons snap back into place, energy released

resolution of MRI

high spatial
low temporal

DTI

diffusion tensor imaging
see where water flows parallel to axons
Uses MRI

CT, MRI, DTI all measure \____ connectivity

structural

GECI

Genetically encoded calcium indicators
Correlate of neural activity (neurotransmitter release)
Image with fluorescence (GFP)

What are the two ways to conduct GECI

1. Viral expression
2. Transgenic (insert into genome)

Electroencephalography (EEG)

- cap with surface electrodes
- record passive electrical signals from cortex

resolution of GECI

low temporal

resolution of EEG

good temporal
poor spatial (weak signals, skull+tissues attenuate signals)

What measures Event-Related Potentials

EEG, averaged over many trials

P1 and P3 of ERP

P1: first recognition of stimulus
P3: decision-making/analysis as a result

latency (ERP)

delay in network communication
time from stimulus to P3

MEG

magnetoencephalography
measures activity parallel to surface of skull (SULCI)
Use SQUIDS to pick up event related fields

MEG resolution vs EEG

Good temporal, better spatial
More expensive!

GECI, EEG, MEG all measure \____ connectivity

functional

fMRI

functional magnetic resonance imaging
Detects inhomogeneities to magnetic field as result of changes in blood flow, CORRELATE of neural activity
Increased activity, increased BOLD (blood flow) to area

resolution of fMRI

pretty good spatial
poor temporal

fMRI measures \____ connectivity

effective
(Structure + Function)

Pharmacology

Manipulating neural activity through drugs

Agonist drugs (pharmacology)

Similar structure as neurotransmitter
Mimics function

Antagonist drugs (pharmacology)

Bind to receptors, block function

Optogenetics

manipulate neural activity, understand causal mechanism
Find way to express light activated channel in targeted neuron, then find way to deliver light to neuron

resolution of optogenetics

high temporal and spatial resolution

is optogenetics used on humans

NO

Transcranial Stimulation resolution

low spatial

Are transcranial stimulation results consistent? Can it be used on humans

No, they are inconsistent
Yes, can be used on humans

deep brain stimulation

Implantable electrode deep in brain
Neurostimulator in chest sends continuous pulses to disrupt neural function at site of electrode

What method is used for Parkinson's treatment

Deep Brain Stimulation
Electrode planted in subthalamic nucleus

resoultion of deep brain stimulation

Good spatial
Good temporal

The technique known as \________ can be used to induce virtual lesions in humans.

Transcranial Magnetic Stimulation

how can transcranial stimulation cause virtual lesions?

Just like it can excite neurons, can also briefly inhibit activity

Morals

personal standards

Ethics

Rules or codes provided by external code

Laws

legal standards that allow for enforcement

What does Nuremburg code state about what we need to do before testing humans

Need to test on other animals

Declaration of Helsinki

1964
Tied Nuremburg Code to Declaration of Geneva
Medically focused
Has been revised up to 2013

What did U.S. Surgeon General do in late 1960's

Orders federally-funded research proposals from Public Health Service to be reviewed for ethics

National Research Act (1974)

Mandated regulations for protection of subjects

the three principles defined by Belmont Report (1979)

Respect for persons
Beneficience
Justice

Respect for persons

Individuals are autonomous and some require protection

Beneficience

minimizing possible harms and maximizing benefits

Justice

Equitable division of benefits

American Psychological Association (APA) Guidelines (1973)

First set of guidelines for protecting human subjects in research
Updated periodically

Did APA ethics code add confidentiality?

Yes

the 3 R's of 1959

for animal experiments:
- replace protected animals
- reduce \# of animals used
- refine procedures to minimize pain & suffering

IRB's

Institutional Review Boards
Review human experimental research

IACUC's

Institutional Animal Care and Use Committees
Review research w/ nonhuman subjects

3 categories of Nazi experiments

1. facilitating military survival
2. develop/test treatments for injury/illness
3. advance racial tenets

Name points of Nuremburg code

- Voluntary informed consent
- Goal should be positive results for society
- Previous data justification for research
- Avoid unnecessary physical and mental suffering
- No implied risk of death or injury
- Risks in proportion to benefits
- Protections against participant risks
- Researchers should be trained and scientifically qualified
- Participants able to quit at any time
- Medical researchers must stop if continuation would be dangerous

Goldberger and Vanderbilts experiments were both unethical because

Caused harm
No consent (prisoners)

Is situs inversus rare in brain?

No, quite common in brain compared to other organs

Which hemisphere protrudes slightly in front

Right

Which hemisphere has more frontal volume

Right

Which hemisphere has more prominent sylvian fissure

Right

Which hemisphere has larger planum temporale (Wernicke's area)

Left

What does left hemisphere do in posterior occipital region

Bend towards the right