Psych 330 Lecture 2

Front 1

Define Attention.

Back 1

Mentally focusing or concentrating on a stimulus or event in order to process it as efficiently as possible

Front 2

Why is it that we can only focus on one stimuli at a time?

Back 2

The brains information processing capacity is limited and cannot encode all inputs at once

Front 3

Define Introspection

Back 3

in

Front 4

Why did behaviourism "die" out ?

Back 4

Because behaviourists only study observable behaviour. Things like Attention cannot be studied just by observations.

Front 5

Explain "seeing"

Back 5

involves focusing attention at different locations to find objects of interest. The act of focusing attention is required.

Front 6

Easily finding an object vs. difficulty finding an object

Back 6

Easy: if object is only thing in view and if it has distinguishing features

Hard: if there are many objects surrounding it and if it blends in (nothing especially unique)

Front 7

Name the four lobes of the brain and a function.

Back 7

Frontal - executive control

Temporal - hearing

Partial - attention processing

Occipital - sight

Front 8

What is phrenology? And who is most responsible for its popularity?

Back 8

The study of the bumps on a person's head as indication of personality.

Gall encouraged this study.

Front 9

Why is the brain tissue convoluted?

Back 9

To fit in the skull

Front 10

Lesion method

Back 10

Systematic destruction of selected brain regions to observe changes in task performance.

Determines locations of neurons involved in particular behaviour

Front 11

Who is Lashley?

Back 11

Scientist who tried to use lesion method to locate the memory region

Front 12

Why aren't lesion methods definitive?

Back 12

Neighboring neurons may become damaged too

Neural pathways may be damaged rather than actual brain region responsible for behaviour

Recovery

Front 13

Who is Galavani?

Back 13

Came up with the idea of neural electricity

Leyden Jar + frog legs = stimulation

Front 14

Grey matter vs. white matter in brain

Back 14

Grey: cell bodies

white: myelin

Front 15

Microstimulation

Back 15

Artificially stimulating brain areas with weak electrical currents

Front 16

Single-cell recording

Back 16

insertion of an electrode directly into a specific brain region while an alert animal performs a task

The firing rate of neuron increases with activity

Studies show that at the onset of a stimulus impulses spike

Front 17

How can we use microsimulation and single cell recording together

Back 17

Can be used in tandem to determine if two areas are linked

If you stimulate one area the other should be affected

Front 18

How is single cell recording useful in studying attention

Back 18

Neurons whose responses vary with performance are said to be associated with the task at hand. Therefore if the task is an attention task than SCR can be used to determine brain areas involved

Front 19

What did Berger (1920s) study?

Back 19

Human neural electricity

Placed electrodes on scalp to measure propagation of electric impulses

Possible to produce record of minute electrical fluctuations known as brain waves

Front 20

Electroencephalography (EEG)

Back 20

Device used to measure electrical activity using surface electrodes on the scalp

Measures changes in polarity along an axon

Is useful in studying sleep states

Front 21

Event-related potentials (ERPs)

Back 21

Waveforms triggered by external events during EEG test

Front 22

How are ERPs used to study the brain / attention

Back 22

Stimulus presentation is repeated many times and the resulting waves averaged to produce a clean waveform with characteristic peaks and valleys representing positive and negative voltage polarities

Front 23

Advantages of Erp method

Back 23

Temporal precision with which brain activity can be measured in response to external stimuli

Front 24

Disadvantages of Erp method

Back 24

Does not indicate precisely where activity occurs because signal is a result of massed neural response

We can overcome this by recording activity of many electrodes and compare activity in different brain regions

Front 25

Rontgen

Back 25

Tried to create N rays, actually created X rays

Front 26

X Rays

Back 26

Denser materials block rays, appear darker on film

Front 27

CT / CAT scan

Back 27

Computed axial tomography.

Structural Imaging technique uses x-rays to create cross-sectional images of brain

Best for hematomas

Front 28

Structural imaging vs functional imaging

Back 28

Structural Imaging: create structural image of brain

Functional Imaging: shows changes in real time during activity

Front 29

Mosso

Back 29

Connected cerebral blood flow and imaging

Bed tilt test: patient lies on balanced bed that "will tilt'' during a mental task because increase blood flow to brain

Front 30

Walter K

Back 30

Bruit over visual cortex → can hear increased blood flow in that area

location of increased blood flow = type of task performed

Front 31

Positron Emission Tomography (PET)

Back 31

creates image of brain blood concentrations

Stage 1: weak radioactive tracer added to blood that emits detectable positions

Stage 2: monitoring of blood flow patterns.

Positron collisions → photons

Photons det table

"Hot spots"of radioactivity= highest blood flow

Front 32

How can we use tomography to create 3D shapes?

Back 32

It takes cross sectional images of brain. If you piece all those together you can get a 3D image.

Front 33

Why is PET useful?

Back 33

Can determine the locus of components of the brains attentional network.

Ie. Can show the neural activity increase in certain cortical areas when attention is shifted between locations

Front 34

What are PET's limitations?

Back 34

1. limited spatial resolution caused by tendency for small regions of activity to blur together

2.subjects must remain very still while performing tasks durng scan

3. Poor temporal resolution because recording time can sometimes take minutes depending on scanning speed and the speed with which blood flow reflect task demands whereas mental phenomena can occur in a fraction of a second

4. It is not clear whether changes in blood flow detected by PET occur in response to excitatory or inhibitory brain processes or both.

Front 35

What is difference imaging?

Back 35

Subtracting the baseline scan from the load scan to create the PET image. Shows the difference between blood flow pattern of baseline activity and pattern during task state

Front 36

Functional Magnetic Resonance Imaging (fMRI)

Back 36

Functional Imaging technique for localizing brain activity using blood oxygen levels

Can be used in conjunction with ERPs to pinpoint the location and the temporal pattern of brain activity

Front 37

BOLD fMRI

Back 37

Blood oxygen level dependent.

Oxygenated blood is less magnetic than deoxygenated blood. When brain area active relative O2 and de-O2 blood increases in local region

Scanner can determine relative activity by detecting changes in magnetic response of blood flow

Front 38

Advantages of fMRl

Back 38

1. Does not require injection of tracer, therefore no limit on number of multiple scans

2. Produces more accurate, higher resolution image

3. Faster temporal resolution (less than 15 sec) than PET

4. Reduced need to run multiple subjects to obtain useful data

Front 39

Transcranial Magnetic Stimulation

Back 39

Involves the placement of coils on person scalp that produces a pulsed magnetic field. This can temporarily change brain activity in neurologically intact individuals by altering potentials of neurons and causing them to fire in a random matter.

Front 40

Limitation to TMS

Back 40

While it can be used to stimulate cortical neurons close to the scout, it cannot stimulate the deeper cortical neurons for subcortical structures without also affecting the neurons that are on top of them