introduction and neuroimaging

Question 1

mathematical model

Answer 1

The use of mathematical language and equations
to describe psychological and/or neural processes.

Question 2

computational model

Answer 2

The use of mathematical language and equations to describe steps in psychological and/ or neural processes (often implemented on a computer).

Question 3

efficient coding models

Answer 3

Theoretical and/or computational models that
explain neural processing by assuming that sensory systems become tuned to predictability in natural environments in ways that economically encode predict- able sensory inputs while highlighting inputs that are less predictable.

Question 4

bayesian models

Answer 4

Theoretical and/ or computational models that employ Bayesian statistical methods to gen- erate an internal model of the source of sensory inputs based upon prior experience.

Question 5

predictive coding

Answer 5

The use of Bayesian models to predict future inputs. If pre- dictions do not match inputs (prediction error), the model is adjusted to improve future predictions.

Question 6

artificial neural networks

Answer 6

Also referred to as connectionist models,
are computational methods that consist of networks of nodes with weighted connections between them. Connection weights increase and decrease following experience in ways that resemble orga- nization of biological neural networks

Question 7

deep neural networks

Answer 7

Artificial neural networks that have a very large num- ber of layers of nodes with millions of connections.

Question 8

What’s the difference between sensation and perception?

Answer 8

A similar distinction:
Sensation is the immediate, basic experience generated by external stimuli.
Perception involves the interpretation of these sensations, giving them meanings and organization.

No clear boundary-fuzzy distinction

Think of sensation as the initial processing carried out by our sensory systems and perception as the interpretive processing of this sensory information

Question 9

Cajal

Answer 9

Cajal- made drawing of organization of neurons in the brain.Neurons do not actually touch( separate cells with tiny gaps(synapse))

Question 10

Loewl

Answer 10

Loewl-excitatory( increase response of next neuron). Inhibatory( decrease response response of next neuron)

Chemical instead of electrical NT travel from axon across the synapse to bind to receptor molecules on the dendrite of the next neuron - some excite or inhibit from firing

Question 11

Neuroimaging

Answer 11

A set of methods that generate images of the structure and/or function of the brain.
Allow us to examine the brain in healthy, living, behaving humans.

Question 12

Dendrite

Answer 12

Receives info

Question 13

Soma

Answer 13

Contains nucleus & multicell organelles

Question 14

Terminal

Answer 14

Synapse with target cell

Question 15

Axon

Answer 15

Conducts AP away from cell body

Question 16

Axon Hillock

Answer 16

Info integrated here.
Generates AP

Question 17

Types of structural NeuroImaging Technologies

Answer 17

Structural techniques:
Computerized Tomography(CT)
Magnetic Resonance Imaging(MRI)

Question 18

Types of functional NeuroImaging Technologies

Answer 18

Functional techniques:
Functioning Magnetic Resonance Imaging(fMRI)
Positron Emission Tomography(PET)
Electroencephalography(EEG)
Event-Related Potential(ERP)
Magnetoencephalography(MEG)

Question 19

Advantages of MRI over CT

Answer 19

Higher resolution(clearer images)
No radiation
Versatile

Question 20

Advantages of CT over MRI

Answer 20

Advantages of CT over MRI:

Advantages of CT over MRI:
More comfortable environment
MRI is very loud
No danger of asphyxiation
No danger of foreign materials

Question 21

How can we determine function?

(B❤️H)

Answer 21

Metabolic imaging: indirect measure of brain activity
based on changes in blood flow
Functional MRI (fMRI)
Positron Emission Tomography (PET)

Question 22

Electromagnetic:direct measure of brain activity

Answer 22

Electroencephalography (EEG), event-related potentials (ERPs)
Magnetoencephalography (MEG)

Question 23

Metabolic Imaging: The Timecourse of Blood Flow

Answer 23

Changes in cerebral blood flow (CBF) are very slow.

Typically 5-20 seconds post-stimulus.

Consequently, metabolic imaging techniques suffer

Question 24

Functional magnetic resonance imaging (fMRI)

Answer 24

Blood oxygen level-dependent (BOLD) signal:
The ratio of oxygenated to deoxygenated hemoglobin that permits the localization of brain neurons that are most involved in a task.

Active brain tissue needs oxygen. Which is delivered by blood( active brain demands more).

See the activity of the brain.

Temporal resolution is slow.

Machines noisy,expensive.

Looks at increase metabolic activity

Question 25

Positron emission tomography (PET)

Answer 25

Small amount of safe, biologically active, radioactive material( a tracer) is introduced in the participants bloodstream.
Camera directs gamma rays emitted from brain region where the tracer is being used the most.

Question 26

Advantages of fMRI

Answer 26

Slightly higher spatial resolution

Does not require a radioactive tracer

Question 27

Advantages of PET

Answer 27

Different radioisotopes provide more flexibility for PET

Radiopharmacology

Question 28

The Subtractive Approach

Answer 28

All parts of the brain are active at all times

Interested in small changes in blood flow during cognitive processes

Need to use a good control condition to isolate the cognition-related activity

Question 29

Example of Subtractive Approach- Peterson, Fox, Posner, Mintun, & Raichle (1989) -Experimental conditions

Answer 29

1) Subjects stared at a crosshair on a computer monitor while their brain activity was monitored via PET imaging
2) Common English nouns appeared on the screen (visual), or were heard over earphones (auditory). The presentation rate was 40 words a minute.
3) The subjects were asked to speak the words that they saw or heard.
4) The subjects were asked to say aloud a use appropriate for the noun they either viewed or heard (e.g., if the word was ‘hammer’ an appropriate response would be ‘hit’)

Question 30

Example of Subtractive Approach-Subtractions

Answer 30

Hearing words: Condition 2 (Auditory) – Condition 1

Seeing words: Condition 2 (Visual) – Condition 1

Speaking words: Condition 3 – Condition 2

Generating words: Condition 4 – Condition 3

Question 31

Electroencephalography (EEG)

Answer 31

Measures brain electrical
activity at the scalp from
the rapid post-synaptic potential changes of of pyramidal cells in the cortex

Dozens of electrodes on the scalp

Can’t learn what individual neurons are doing or pinpoint exact are of neural activity

Localize population of neurons and measure their activities with excellent temporal accuracy

Question 32

MRI

Answer 32

Uses responses of atoms to strong magnetic fields to form images of structure in the brain

Question 33

Event related potential (ERP

Answer 33

Created by averaging together many EEG trials time locked top a specific event

Tells us about temporal processing of a stimulus

Question 34

Magnetoencephalography MEG

Answer 34

A technique similar to eeg that measures changes in magnetic activity across populations of many neurons in the brain

Has the same high temporal resolution as EEG, but better spatial resolution

Provides good measure of neuronal timing

Shows where in the brain neurons are. Most active

Shows that very small changes in local magnetic fields accompany the small electrical changes that take place when a neuron fires - use small devices to measure these tiny magnetic field changes

Simple and cheap

Question 35

EEG vs Meg

Answer 35

EEG:
Relatively inexpensive
Portable

Equivalent:
Safe/non-invasive
Very high temporal resolution (1 ms accuracy)

MEG
Better spatial resolution (though not as good as fMRI)