chapter 2: cognitive neuroscience

Question 1

neurons

Answer 1

Cognitive Neuroscience: the study of the physiological basis of cognition
(Goldstein, 2019

Question 2

levels of analysis

Answer 2

Levels of analysis refers to the idea that a topic can be studied in a number of different ways, with each approach contributing its own dimension to our understanding

Question 3

early conceptions of neurons

Answer 3

Microscope: brain tissue looked like it was made of a continuous network called a nerve net.
* like a highway system in which one street connects directly to another, but without stop signs or traffic lights. When visualized in this way, the nerve net provided a complex pathway for conducting signals uninterrupted through the network.

Golgi staining: structure of neurons could be seen using a staining solution
of silver nitrate.

Golgi staining of newborn animal brains: Cajal discovered individual units
in the brain and the idea of a nerve net was replaced with neuron doctrine.

• Neuron doctrine: individual cells are not continuous with other cells.
• neuron doctrine—the idea that individual cells transmit signals in the nervous system, and that these cells are not continuous with other cells as proposed by nerve net theory.
  Each cell sends signals

Question 4

structure of neurons

Answer 4

1) Cell body (soma): area of metabolic activity that
keeps the cell alive.

2) Dendrites: receives signals from other neurons.

3) Axon (nerve fiber): transmits signal from one
neuron to another.

4) Synapse: A gap exists between the axon of one neuron and the dendrite of another
called a synapse.

5) Neural circuits: Group of connected neurons are called neural circuits

Question 5

resting potential

Answer 5

Resting potential: inside the neuron is -70 mV more negative than
outside.

At Rest the inside of neurons are -70 millivolts an action potential is the temporary reversal of a neurons interior polarity from being negatively charged to being positively charged

this occurs because of the opening of voltage sensitive sodium ion channels that allow positively charged sodium ions inside the neuron

Question 6

action potential

Answer 6

Nerve impulse: neuron is stimulated and reverses the interior polarity of
the neuron to +40 mV. This reversal is called an action potential.

see figure

Question 7

what is a device that measures electrical signals

Answer 7

Microelectrodes: device that measures electrical signals. Can be used to
measure action potentials.

Characteristics of an action potential are determined by using a measurement device known as micro electrodes in the figure on the screen you will see that the microelectrode has two points of reference

one is placed inside the neuron and the other is outside the neuron. the resting potential inside the neuron is -70 millivolts but when there is a nerve impulse the microelectrode records a change of -70 milivolts to that of +40 millivolts, eventually the interior polarity returns to -70 millivolts the resting potential

Question 8

Neurons Communicate via Action Potential

Answer 8

• Action potentials travel to the axon terminal buttons (end of the axon) and
  trigger synaptic vesicles containing neurotransmitters (chemical
  messengers) to release the neurotransmitters across the synapse.
• The neurotransmitters cross the synapse and bind to the dendrites of a
  nearby neuron.

notes:

action potentials are important for communication between neurons when action potentials occur they travel down to the end of the Axon called the Axon terminal buttons and trigger the release of neurotransmitters which are chemical messengers such as GABA endorphins and dopamine among others

these neurotransmitters cross the synapse and bind to a nearby neurons dendrites

Question 9

a characteristic of action potentials

Answer 9

Intensity of stimulation changes the rate of action potentials traveling
down the axon.

see figure

the shape and height of action potentials are all the same regardless of the intensity of this stimulation however the rate of neural firing changes with stimulus intensity for example when there is light stimulus intensity the rate of action potentials traveling down the Axon is slow relative to when there is strong stimulus intensity

Question 10

representation by neural firing

Answer 10

Principle of Neural Representation

1) Representation from processing of neural information from sensory
receptors.

2) Neural representation involves different parts of the brain

Question 11

representation by neural firing

feature detectors

Answer 11

Feature detectors: neurons that respond to specific stimulus features
such as orientation, movement and length.

Question 12

representation by neural firing

experience-dependent plasticity

Answer 12

1) Feature detectors that respond to stimuli that one is exposed to will
be plentiful

2) Feature detectors that respond to stimuli that one is NOT exposed
to will be lost

Question 13

Representation by Neural Firing

Hierarchical Processing:

Answer 13

As complexity of object increases, higher areas of the brain involved with
its perception.

Question 14

Representation by Neural Firing

neurons in the visual cortex

Answer 14

Neurons in the Visual Cortex: process simple stimuli (e.g., oriented bars)

Question 15

Representation by Neural Firing

neurons in the temporal lobe

Answer 15

Neurons in the Temporal Lobe: process complex visual stimuli (e.g., hands
and faces)

Feature detectors in the temporal lobe
responds to complex stimuli (Gross et al., 1969, 1972)

Question 16

Representation by Neural Firing

what are three types of sensory coding?

Answer 16

Sensory Coding: representation of the environment based on the neural
firing.

Three types of sensory coding:

1. Specificity Coding: representation of an object based on the neural firing
   of a specialized neuron that responds to that object.
2. Population Coding: representation of an object by pattern of neural firing
   from large group of neurons.
3. Sparse Coding: representation of an object by pattern of neural firing from small group of neurons.

Question 17

(localized representation)

Answer 17

One of the basic principles of brain organization is localization of function—specific functions are served by specific areas of the brain. Many cognitive functions are served by the cerebral cortex, which is a layer of tissue about 3 mm thick that covers the brain

Localized representation: activity in a specific part of the brain is
associated with a function. We know this from brain imaging (PET and
fMRI) and studies that demonstrate a double dissociation.

Question 18

Localized Representation

what is double dissociation?

Answer 18

Double dissociation: Damage to one part of the brain results in
impaired function A and intact function B. Damage to another part of the brain results in intact function A and impaired function B.

Double dissociation A situation in which a single dissociation can be demonstrated in one person and the opposite type of single dissociation can be demonstrated in another person (i.e., Person 1: function A is present, function B is damaged; Person 2: function A is damaged, function B is present). (2)

Question 19

Localized Representation

Cognitive functions. Can be divided into
4 lobes.

Answer 19

Cerebral cortex: 3 mm thick
outer layer of the brain used for
Cognitive functions. Can be divided into
4 lobes.

notes:

If you were to cut open the skull what you would see is the cerebral cortex it is the outer 3mm of the brain and it is where a lot of higher level processing of sensory information occurs

the cerebral cortex can be divided into four types of lobes based on their specialized functions appropriately named is the frontal lobe that sits at the front of the brain

above both of your ears of what we call the temporal lobe

the occipital lobe is at the back of the brain and at the very top of the brain is the parietal lobe

Question 20

4 lobes of the brain

Answer 20

1) frontal lobe
2) parietal lobe
3) occipital lobe
4) temporal lobe

see image

Question 21

frontal lobe

Answer 21

thinking / problem solving

coordinate senses

the frontal lobe specializes in thinking, problem solving and coordinating senses. you will notice that in the frontal lobe is an area called Broca’s area

broca’s area is specialized for producing speech if there is damage to the broka’s area speech production is impaired and individuals would have difficulty making fluent speech sounds

Question 22

parietal lobe

Answer 22

somatosensory cortex

touch perception

pressure

pain

the parietal lobe at the top of the brain holds the somatosensory cortex for touch perception that is stimuli such as pressure and pain are processed here

Question 23

occipital lobe

Answer 23

visual cortex

visions

the occipital lobe holds the visual cortex which is a specialized area of for vision processing it is here that visual stimuli are first processed when the visual stimuli are complex this information gets transferred to other parts of the brain such as the temporal lobe

Question 24

temporal lobe

Answer 24

auditory cortex

hearing

fusiform face area

processing of complex virtual stimuli

the temporal lobe just above the ears is involved with auditory processing which just means the processing of sound stimuli. in addition to processing auditory information this is a specialized area for face processing and other complex visual stimuli

the Wernicke’s area is found in the temporal lobe it is an area that specialized in speech comprehension. those who have damage to the wernicke’s area in the temporal lobe have difficulty understanding speech

Question 25

broca’s area

Answer 25

for speech production

in the frontal lobe

Question 26

wernicke’s area

Answer 26

for speech comprehension

in the temporal lobe

Question 27

double dissociation between broca’s area and wenicke’s area

Answer 27

you might notice a double dissociation between broca’s area and wenicke’s area. recall from the slides in the textbook that a double dissociation refers to damage to one part of the brain that result in impaired function A and intact function B and damage to another part of the brain result in intact function A and impaired function B

I stated that the brocas areas for speech production if there’s damage to this part of the brain speech is impaired however if Wernicke’s area is still intact they can still comprehend speech

in contrast if wernicke’s area is damaged one would have difficulty with speech comprehension but no difficulty with speech production thus this is the double dissociation

Question 28

Localized Representation

Damage to the FFA could
result in..

Answer 28

Damage to the FFA could
result in prosopagnosia
(impaired facial recognition)

parts of the brain specialize in the processing of specific stimuli and we discussed how simple visual stimuli are processed in the visual cortex that’s located in the occipital lobe at the back of the brain

however when the visual stimuli are complex this information gets processed in other parts of the brain such as the temporal lobe

through brain scans it has been found that the fusiform face area responds to face stimuli. research has shown that damage to the fusiform base area can result in prosopagnosia which is impaired facial recognition

the parahippocampal place area responds to the outdoors a building or inside A room and the extra strike body area responds to body parts such as an arm stick figures of people or even the shadow of a body

Question 29

Distributed Representation

Answer 29

Distributed representation: activity in multiple areas of the brain is
associated with a function.

Processing that involves multiple areas of the brain:
* Face processing
* Remembering
* Production and comprehension of speech

notes:

while I’ve discussed the specialized functions of specific brain areas keep in mind that multiple regions of the brain are needed for a function such as face processing for example facial recognition might involve the fusiform phaseout area however the attractiveness of the face is processed in the frontal lobe and identifying the location of where the person is looking involves the temporal lobe

another example of distributed representation is that a remembering remembering is associated with brain activity in the frontal temporal and occipital lobes

yet another example of distributed representation is that of speech production and comprehension while we focused on broca’s and wickenaris areas regions outside of these areas can also impact the production and comprehension of speech

Question 30

neural networks

Answer 30

Default mode network (DMN): a neural network that is active when one is not
engaged in a task.

• Activity of the DMN is associated with mind wandering
• Might be involved with attention, memory, and creativity

Question 31

reflection questions

Answer 31

1.What are some characteristics of an action potential?

2.What does double-dissociation mean?

3.Name the 4 lobes of the cerebral cortex and their functions.

Question 32

chemical messengers are called

Answer 32

neurotransmitters

Question 33

Which of the following is NOT a type of sensory coding?

Answer 33

feature coding

sensory coding:

Specificity coding
Sparse coding
Population coding

Question 34

the default model network is most closely associated with

Answer 34

MIND WANDERING
Visual processing of simple stimuli (e.g. vertical bar)
Face processing
Touch perception

Question 35

Cognitive neuroscience is the study of the physiological basis of cognition. Taking a levels-of-analysis approach to the study of the mind involves research at both behavioral and physiological levels.

Question 36

Ramon y Cajal’s research resulted in the abandonment of the neural net theory in favor of the neuron doctrine, which states that individual cells called neurons transmit signals in the nervous system.

Question 37

Signals can be recorded from neurons using microelectrodes. Edgar Adrian, who recorded the first signals from single neurons, determined that action potentials remain the same size as they travel down an axon and that increasing stimulus intensity increases the rate of nerve firing.

Question 38

4. The principle of neural representation states that everything that a person experiences is based not on direct contact with stimuli, but on representations in the person’s nervous system.

Question 39

Representation by neurons can be explained by considering feature detectors, neurons that respond to complex stimuli, and how neurons are involved in specificity coding, population coding, and sparse coding.

Question 40

The idea of localization of function in perception is supported by the existence of a separate primary receiving area for each sense, by the effects of brain damage on perception (for example, prosopagnosia), by recording from single neurons, and from the results of brain-imaging experiments.

Question 41

Brain imaging measures brain activation by measuring blood flow in the brain. Functional magnetic resonance imaging (fMRI) is widely used to determine brain activation during cognitive functioning. Brain-imaging experiments have measured the response to still pictures to identify areas in the human brain that respond best to faces, places, and bodies, and the response to movies to create a brain map indicating the kinds of stimuli that activate different areas of the brain.

Question 42

The idea of distributed processing is that specific functions are processed by many different areas in the brain. One reason for the activation of many areas is the multidimensional nature of experience. This principle is illustrated by the multidimensional nature of seeing a face, remembering, and producing and understanding language.

Question 43

Neural networks are groups of neurons or structures that are connected structurally and also that are functionally related.

Question 44

structural connectivity defines the neural highway system of the brain. It has been measured using track weighted imaging.

Question 45

Functional connectivity occurs when different areas have temporally correlated responses. Measuring resting-level fMRI has emerged as one of the ways to measure functional connectivity, but functional connectivity can also be measured by task-related fMRI.

Question 46

A number of different functional networks, such as visual, auditory, salience, executive function, and motor networks, have been determined using resting-level fMRI.

Question 47

A full description of networks needs to include the dynamic aspects of network activity.

Question 48

Thedefaultmodenetworkisdifferentthanothernetworks because its activity decreases when a person is engaged in
a task, but then increases when the brain is at rest. The function of the DMN is still being researched, but it
has been suggested that it may play important roles in a number of cognitive processes, which we will discuss later in the book.

Question 49

Progress in understanding the physiology of cognition has depended on advances in technology. This is demonstrated by considering the connection between technology and answering three basic questions: The Representation Question, The Organization Question, and The Communication Question.