PSY 223 Intro Cog Exam 1 Detail

Question 1

Cognitive neuroscience:

Answer 1

the neuroscience of cognitive processes

Question 2

Neuroscience:

Answer 2

study of the structure and function of the nervous system

Question 3

Cognition:

Answer 3

the mental action of acquiring knowledge and understanding through thought, experience, and the senses

Sensory info can contribute to thoughts
Give rise to neural activity

Question 4

Neurology:

Answer 4

function and pathology of the nervous system
That brian region is important for that cognitive function

Question 5

Psychology:

Answer 5

study of the mind and its implications for behavior
What types of cognitive process we might want to examine

Question 6

Broad relationships between brain and behavior

Localization of function:

Answer 6

each function is localized to a brain region / each brain region has a specific function - one to one mapping

Question 7

Broad relationships between brain and behavior

Mass action:

Answer 7

each function can’t necessarily be localized to a specific brain region / each brain region isn’t specialized for a particular function - that brain wasn’t specialized all of brain was doing all tasks

Question 8

Neuronal Signaling

Answer 8

Chemical NT carry signal

Electrical impulses carry signals within a neuron

inputs from other neurons cause excitatory or inhibitory postsynaptic potentials at the dendrites

postsynaptic potentials (PSPs) may “add up” with temporal or spatial summation

Question 9

post-synaptic potential:

Answer 9

change in potential that a neuron causes downstream

from a single action potential, a neuron might not be able to induce an action potential on its own

If the PSPs add up to increase membrane potential enough, this may cause a neuron’s membrane potential to reach a critical threshold, an action potential is generated

Question 10

spatial summation examples

Answer 10

neurons in primary visual cortex (V1)
neurons in the superior olive (sound localization in the horizontal plane)
neurons in middle temporal area (MT)

Question 11

Ways to compare methods:
temporal/spatial summation

Answer 11

Spatial summation:
Simultaneous EPSPs in diff. parts of neuron
add and sum to produce AP
- spatial summation (multiple neurons summing across space)
location of brain region
- how resolved in space is the method, i.e. how specific is the spatial location of this method? - across neurons (for example, neuron vs. broad region of brain)

Temporal summation:
Rapid repeat EPSPs same location (EPSP lasts a while)
add and sum to produce AP
- temporal - when there is a change in brain activity
- how resolved in time is the method, i.e. how specific is the timing of this method? - across time (for example, milliseconds vs. minutes)

EPSPs summate across time from one neuron (temporal summation) or across space from multiple neurons (spatial summation)

Question 12

single-cell recording:

Answer 12

measure electrical potential/activity/ signal in a single neuron (good spatial resolution, good temporal resolution) - individual neuron

Question 13

electrocorticography (ECoG):

Answer 13

measure electrical potential/ activity/signal across neurons, recording directly on or in the brain (good spatial resolution, good temporal resolution) - group of neurons so a larger region

Question 14

electroencephalography (EEG):

Answer 14

measure electrical potential/ activity/signal across neurons from the scalp (poor spatial resolution, good temporal resolution) - not sure where its coming from

Question 15

magnetoencephalography (MEG):

Answer 15

based on magnetic signal generated from electrical postsynaptic activity, recorded at the scalp (poor spatial resolution, good temporal resolution)

Question 16

Single-cell activity:

Answer 16

Single-cell activity: recorded in voltage, but it is often reported by the presence of an action potential

“All or none” principle of the action potential: a neuron usually has a characteristic action potential shape

Question 17

Representations of the body in cortex for M1 and S1

Answer 17

Somatotopy: different parts of M1 / S1 correspond to planning and control of movement / somatosensation in different body parts
- So there are neurons that respond to specific body parts
- Individual neurons have a specific body part
- So the group of neurons are all near each other

Each side of the brain M1 and S1 corresponds to the contralateral side of the body

Not consistent with anatomical size (e.g. more brain tissue devoted to hands than arms)

Not consistent with anatomical order - not from top to bottom or left to right

Question 18

Primary motor cortex M1

Answer 18

Neurons located nearby each other are more likely to be more active when planning movement of the same body part

Neurons more active when planning movement of the same body part differ with respect to the direction of movement which leads to the most action potentials

An individual neuron in M1 fires the most action potentials during planning of movement of a particular body part AND movement of that body part in a specific direction - start point doesn’t matter just same general direction and not in relation to oneself just direction of movement of a body party

Question 19

Motivation for neuroimaging

Answer 19

Take advantage of the fact that more active brain regions require more resources - more blood

Indirect measure of neural activity

Whole team of brain regions want to know which is more active

Neuroimaging looking at resources of more blood

Question 20

Neuroimaging methods measuring blood flow

Answer 20

more active brain regions use more (oxygenated) blood (good spatial resolution, poor temporal resolution)

functional magnetic resonance imaging (fMRI): tracks blood flow based on the magnetic properties of oxygenated vs. deoxygenated blood

Positron emission tomography (PET): Tracks blood flow using a radioactive tracer

Which brain regions are more active

Question 21

“Subtraction logic”: PET and fMRI

Answer 21

Interested in a task and find a second task that’s very close to first task

Reading interested in but also picks up vision and breathing

Not enough saying flowing blood instead we must subtraction

Question 22

Lesion studies

Definition:

Electrophysiology and neuroimaging

Answer 22

Definition: “a region in an organ or tissue which has suffered damage through injury or disease”

Damaging brain region and how that imparies cog function

Lesions can identify if a brain region is necessary for a function: if someone is missing brain region A, and they can’t perform function B => brain region A is necessary for function B Lesion studies

Electrophysiology and neuroimaging identify brain regions involved in, or more active during, a function: if brain region A is more active during function B => then it is probably involved in function B

generally good spatial resolution - which area

Question 23

Transcranial Magnetic Stimulation (TMS):

Answer 23

creates reversible/temporary lesions in humans by creating a magnetic field that influences electrical properties of the brain

Question 24

Lesion

permanent vs temporary

Answer 24

generally good spatial resolution - which area

permanent
poor temporal resolution - know brain region is important for tasks but not when

temporary
humans: transcranial magnetic stimulation (TMS)
animals: cooling or pharmacological
good temporal resolution
for humans, better control of locations than permanent lesions

Question 25

Lesion: Analysis approach

Answer 25

Single Dissociation: damaging a single brain region and dissociating particularly properties of that brain region → control normal is good at task and lesion to region 1 says they can’t do task

Double Dissociation: two brain regions are selectively associated with two different tasks

Question 26

Transduction:

Answer 26

“translation” of external, environmental stimuli into changes in neuronal signaling

Question 27

Sensation:

Answer 27

“neural processes that correspond most closely to the concept of detection”

Question 28

Perception:

Answer 28

internal experience of the external world; “identification of features of what is being sensed”

Question 29

Action:

Answer 29

“isolated acts of motor control…also goals or plans that can be abstracted from isolated movements” - having thought and then making motor movement

Question 30

Receptive field:

Answer 30

sensory stimulus that provides maximal changes in the membrane potential of a neuron

Question 31

Vision

Transduction

visual field

receptive fields

Answer 31

Transduction - Each photoreceptor has a receptive field in specific part of visual field

Altogether, all of the photoreceptors’ receptive fields form one’s visual field

Retinal ganglion cell - visual field
receptive fields: ON-center (light in middle) and OFF-center (light off in middle)

Question 32

optic chiasm:

Answer 32

where some nerve fibers cross from the left and right eyes => each side of the brain has visual information from the contralateral visual hemifield

Question 33

Organization of V1

cortical magnification

retinotopy

Answer 33

cortical magnification - Visual information presented near the center of the visual field is represented by larger areas of cortex
The majority of neurons in V1 have receptive fields from the center of the visual field (fovea, central portion of the retina)
Thus information central in the visual field is “magnified”

retinotopy spatial relationships preserved from retina - neurons near each other

Question 34

Neurons in primary visual cortex
Defined by type of receptive field

Answer 34

1) Cells with ON center / OFF surround receptive fields, like ganglion cells (in a particular region of the visual field)

2) simple cell: detects points of light in a single orientation in a particular region of the visual field — like signal line in visual field so diff direction or location

Question 35

The information leaving the visual cortex divides into 2 main streams of visual information

Answer 35

dorsal: “where” (where in space are these features located?)

ventral: “what” (what do these features comprise?)

Question 36

dorsal: “where” (where in space are these features located?)

MT

Answer 36

A neuron in MT fires the most action potentials in response to visual movement: A bar of light moving in a specific region of one’s visual field and in a specific direction

Motion processing in region MT thanks to spatial summation

Neurons firing AP in response to light

Question 37

ventral: “what” (what do these features comprise?)
object recognition:
4 things -

Answer 37

object recognition: Matching representations of organized sensory input to stored representations in memory
– Faces several challenges

1) where does it end? - neurons have lines of light or one for corners but not effective to have neurons only doing one single line similar to grandma so you can recognize here even if she gets a haircut

2) object constancy: can be viewed as a constant object despite change in perspective, size, etc. - so different shapes of blue car can still see that it’s a blue car

3) object composition: many objects consist of the same collection of features
Another example: Different objects, similar sets of features

4) aperture problem: integrating information from early visual regions, where neurons are sensitive to small regions of visual space, into a coherent picture across larger regions of visual space - can put the whole image together to a larger picture

Question 38

Solution to “where does it end” and object constancy

Answer 38

“What”/ventral pathway and inferior temporal cortex has many solutions to the challenges of object recognition

“Distributed coding”: A response to an object is distributed across increased activity from several neurons — Way we could for individual object is distributed across several neurons

Neurons are sensitive to more complex sets of features (such as stimuli on the right) but no “top level” such as e.g. a neuron only sensitive to one’s grandmother

Increased activity to a set of neurons

Question 39

Solution to aperture problem

Answer 39

“What”/ventral pathway and inferior temporal cortex has many solutions to the challenges of object recognition

group features together in principled ways

Similarity/Proximity: link alike items together

Continuity/Closure: link items with missing pieces - some parts of cat is missing still link

Expectations/Pre-existing knowledge

Question 40

Audition: Input signal

Sound

Frequency

Intensity/amplitude

Transduced

Combined

Answer 40

Sound = changes in (oscillatory) air pressure over time

Frequency (oscillations per second): perceived as pitch —– Higher frequency is pitch

Intensity/amplitude: perceived as loudness —- Height of signal then how loud sound is perceived

Transduced inner hair cells of coahela

Information from left ear and right ear is combined to localize where sound is something from and then sent to A1

Question 41

Low frequencies (below 100 Hz):

Answer 41

A neuron fires an action potential at a particular phase for a certain frequency (e.g. peak), so its timing is in sync with the wave

Question 42

Volley principle (100-4000 Hz):

Answer 42

a group of neurons (“volley”) encodes the frequency, because no one neuron can fire action potentials quickly enough on its own
Rate at which air pressure oscillate is faster than neurons so they need to act as a group to encode a frequency

Question 43

Tonotopy (100-20000 Hz):

Answer 43

Tonotopy (100-20000 Hz): sound causes maximum vibration for hair cells at one location on the basilar membrane in the cochlea, which varies in width and height - at extreme low or high frequency
Tonotopy: systemic organization of characteristic frequency within an auditory structure

Question 44

Sound localization

Answer 44

Horizontal: Relies on the differential timing of information from the left and right ears - superior olive - relies on spatial summation from both ears

Question 45

Somatosensory receptors

Somatization - all over the body - left side of brain is for right side of body processed in primary somatosensory cortex (S1)

Answer 45

1.mechanoreceptors: receptive to mechanical forces, such as pressure, texture, vibration, stretch

2.thermoreceptors: receptive to heat and cold

3.nociceptors: receptive to sensory processes signaling (risk of) tissue damage, which can trigger pain response

Question 46

Receptive fields of somatosensory receptors
vary in

Answer 46

1.location of the body part it covers
2.size of the body part it covers
3.the type of stimulus it is sensitive to
4.for frequency-sensitive mechanoreceptors, the optimal frequency of vibration

Question 47

Controlling for adaptation when measuring (somatosensory) receptor responses

adaptation:

Answer 47

adaptation: “decreased response to a stimulus as a result of recent exposure to it” - neuron can adapt with lost of exposure - so exposed to cold

Question 48

Cerebellum

Answer 48

Motor coordination
motor sequences requiring precise aim and timing
fine-tuning of movements
posture (“the position in which someone holds their body when standing or sitting”)

Question 49

Basal ganglia

Answer 49

Regulating motor activity, such as starting and stopping actions
Parkinson’s disease: specific type of damage to the basal ganglia relevant symptom of
Parkinson’s disease: difficulty initiating and maintaining motor movements

Question 50

Mirror neurons

Answer 50

Fire the most action potentials in response to
1) a specific action or set of actions performed by the self or
2) the same (set of) action(s) as in 1, but performed by another

Some seem to fire more action potentials in response to specific actions performed by another; some respond to a wider range of actions

These actions usually consist of a series of individual movements

Question 51

action potentials are regenerated at

Answer 51

the nodes of Ranvier

Question 52

Axon hillock

Answer 52

origin of the action potential

Question 53

Supplementary motor cortex

Answer 53

most active just before a rapid series of movements
e.g. push, turn, then pull a mechanical key, playing piano or guitar

Question 54

Premotor cortex

Answer 54

primarily active during preparations for a movement (e.g. grab a cup)
somewhat active during the actual movement