Chapter 2: Cognitive Neuroscience Flashcards
What is COGNITIVE NEUROSCIENCE?
field concerned with studying the neural basis of cognition
What is meant by LEVEL OF ANALYSIS?
a topic can be understood by studying it at a number of different levels of a system
we can study psychology of cognition at levels ranging from the whole brain, to structures w/i the brain, to chemicals that create electrical signals
What is a NEURON?
Cell that is specialized to receive and transmit information in the nervous system
What is a NERVE NET?
A network of continuously interconnected nerve fibres, contrasting with neural networks connected by synapses
Who developed a staining technique that allowed for a more complete picture of tiny parts of the brain?
Camillo Golgi in the 1870s
What did Ramon y Cajal use to study brain tissue?
Glogi stain and tissue from the brains of newborn animals
What is the NEURON DOCTRINE?
The idea that individual cells transmit signals in the nervous system, not continuous with other cells
What are the basic parts of a neuron?
- Cell body
- Dendrites
- Axons (nerve fibres)
What is a SYNAPSE?
A small gap between the end of a neuron’s axon and the dendrites of another neuron
What are NEURAL CIRCUITS?
Groups of interconnected neurons
What are RECEPTORS in the context of neurons?
Neurons specialized to pick up information from the environment, such as from the eye, ear, and skin
Who won the Nobel Prize in 1906 for contributions to cellular study?
Ramon y Cajal
What are MICROELECTRODES?
Small shafts of hollow glass filled with a conductive salt solution that can pick up electrical signals
What is RESTING POTENTIAL?
Difference in charge between the inside and outside of a nerve fibre when the fibre is at rest
What is a NERVE IMPULSE?
An electrical response propagated down the length of an axon, also known as ACTION POTENTIAL
What happens to the charge inside the axon during an action potential?
It increases to +40 millivolts before reversing course and returning to resting potential
What is a NEUROTRANSMITTER?
A chemical released at the synapse in response to incoming action potentials
What did Edgar Adrian study in relation to nerve firing and sensory experience?
The firing of a neuron from a skin receptor and its changes with differing pressures
How does the rate of nerve firing relate to sensation intensity?
Crowded electrical signals indicate a strong sensation; separated signals indicate a feeble sensation
What does ‘Quality across the senses’ refer to?
The different experience associated with each of the senses
What is ‘Quality within a particular sense’?
Different aspects of experience within a sense, such as color, movement, shape, or identity of a face in vision
True or False: All action potentials have different heights and shapes depending on the quality of the stimulus.
False
Fill in the blank: The _______ is the mechanism by which information is transmitted through the nervous system.
Action potential
What is the principle of neural representation?
Everything a person experiences is based on representations in the person’s nervous system.
What decade did researchers begin focusing on recording from single neurons in the primary visual receiving area?
1960s
Why did vision dominate early research in neuroscience?
Stimuli could be easily controlled by creating patterns of dark and light on a screen; a lot was already known about vision.
What was discovered when researchers recorded neurons in areas outside the primary visual area?
Many neurons at higher levels of the visual system fire to complex stimuli like geometrical patterns and faces.
What does a specific stimulus cause in terms of neural firing?
Neural firing that is distributed across many areas of the cortex.
Where are vision and cognitions like memory created according to the research findings?
In many different areas, not just the primary visual receiving area.
What concept has emerged from the idea of neural signals transmitted between many destinations in the brain?
The conception of the brain as containing a vast highway system described in terms of ‘neural networks.’
Fill in the blank: The idea of neural signals transmitted between many destinations has led to the concept of the brain as a _______.
[neural networks]
Who won the Nobel Prize in 1981 for their research on neurons and visual stimuli?
David Hubel and Torsten Wiesel
They presented visual stimuli to cats to study neuron responses.
What term did Hubel and Wiesel use to describe neurons that respond to specific stimulus features?
FEATURE DETECTORS
These features include orientation, movement, and length.
What is EXPERIENCE-DEPENDENT PLASTICITY?
The structure of the brain is changed by experience
Example: Kittens reared in environments with limited orientations showed altered neuron responses.
What happens to feature detectors in a kitten’s visual cortex if it is raised in an environment with only vertical stimuli?
Neurons respond mainly to verticals and no neurons respond to horizontals
This was demonstrated by Blakemore and Cooper in 1970.
What role does the visual cortex play in visual processing?
It is an early stage of visual processing and receives signals from the eyes
It is located in the occipital lobe.
What is the TEMPORAL LOBE responsible for?
Language, memory, hearing, and vision
It contains mechanisms important for these functions.
What did Charles Gross discover about neurons in the temporal lobe?
Neurons respond to complex stimuli, such as hand-like shapes and faces
This was observed in studies conducted in 1969 and 1972.
Define HIERARCHICAL PROCESSING in the context of visual perception.
Processing that occurs in a progression from lower to higher areas of the brain
Neurons in the visual cortex send signals to higher levels for more complex stimuli.
What is a SENSORY CODE?
How neurons represent various characteristics of the environment
This includes how different stimuli are encoded by neuronal firing patterns.
What does SPECIFICITY CODING suggest?
An object could be represented by the firing of a specialized neuron that responds only to that object
This idea is considered unlikely due to the variety of stimuli.
What is POPULATION CODING?
The representation of a particular object by the pattern of firing of a large number of neurons
This allows for a large number of stimuli to be represented.
Define SPARSE CODING.
When a particular object is represented by the firing of a small group of neurons
The majority of neurons remain silent during this process.
What recent discovery was made about neurons in the temporal lobe during epilepsy surgery?
Neurons responded to very specific stimuli, such as faces of publicly known people
This supports the concept of sparse coding.
How are memories represented in the brain?
By the firing of neurons
This may involve principles of population and sparse coding as well.
What is the difference between perceptions and memories?
Perceptions are associated with present stimuli, while memories are associated with past information
This distinction highlights the nature of neuronal firing related to each.
What does localization of function refer to?
Specific functions are served by specific areas of the brain
What is the cerebral cortex?
A layer of tissue ~3mm thick that covers the brain
What was the principle of cortical equipotentiality?
The idea that the brain operated as an indivisible whole as opposed to specialized areas
Who studied Broca’s area and in what year?
Paul Broca in 1861
What is Broca’s aphasia?
Patients with slow, labored, ungrammatical speech caused by damage to Broca’s area
What did Carl Wernicke describe in 1879?
Patients with fluent but incoherent speech due to damage to Wernicke’s area
What is Wernicke’s aphasia?
Meaningless speech and unable to understand others’ speech
What did studies of soldiers in WWI show about the occipital lobe?
Damage resulted in blindness
What is the role of the auditory cortex?
Receives signals from the ears and is responsible for hearing
What does the somatosensory cortex do?
Responsible for perceptions of touch, pressure, and pain
What is the function of the parietal lobe?
Contains mechanisms responsible for sensations caused by skin stimulation and some aspects of vision
What is the function of the frontal lobe?
Receives signals from all senses and coordinates them, as well as thinking and problem solving
What is PROSOPAGNOSIA?
An inability to recognize faces despite being able to tell a face is a face
What is double dissociation in neuropsychology?
A situation where a single dissociation is demonstrated in one person and the opposite in another
Fill in the blank: Damage to the left part of the occipital lobe causes blindness in the _______ part of visual space.
upper-right
What type of research has identified areas important for perceiving motion?
Neuropsychology research
What is the significance of double dissociation?
It allows us to conclude that functions A and B are served by different mechanisms which operate independently
What is the primary focus of neuropsychology research?
To determine whether a particular area of the brain is specialized for a specific cognitive function
What method demonstrates localization of function in neuroscience?
Single-neuron recording
This method involves measuring the activity of individual neurons to understand their specific functions.
What percentage of neurons in a small area of a monkey’s temporal lobe respond to faces according to Doris Tsao’s study?
97%
This finding indicates a high level of specialization for face recognition in that brain region.
In which part of the brain did Doris Tsao conduct her research?
Lower part of the monkey’s temporal lobe
This area is crucial for processing visual information, particularly faces.
What human condition is associated with the area in the brain where face-responsive neurons were found?
Prosopagnosia
Prosopagnosia is a neurological condition characterized by the inability to recognize faces.
What type of studies primarily support the findings of neuron responses to faces?
Brain imaging studies
Brain imaging techniques allow researchers to visualize brain activity in response to various stimuli.
What does the multidimensional nature of cognition refer to?
The fact that even simple experiences involve combinations of different qualities.
List some emotional aspects we respond to when identifying a face.
- Emotional aspects
- Where someone is looking
- How the parts of the face move
- How attractive a face is
- Whether the face is familiar
What is distributed representation?
Occurs when a specific cognition activates many areas of the brain.
Are short term memories and long term memories served by the same parts of the brain, or different?
Different
How do different types of memories activate different areas of the brain?
Thinking about episodic memories and semantic memories activates different areas.
What are some components of memories?
- Visual
- Auditory
- Olfactory
- Emotional (good and bad)
What did Wernicke propose about language?
Language goes beyond isolated regions to include connections between them and other areas.
What did modern researchers demonstrate about the physiology of language?
It involves more than just two separate localized areas.
Can problems with language be caused by damage to areas other than Broca’s and Wernicke’s?
Yes.
Where does processing sentence grammar occur in the brain?
TOccurs throughout the language system.
What are the two sets involved in language pathways?
- One for processing sounds, production of speech, and saying words
- One for understanding words
True or False: Both sets of language pathways are involved in understanding sentences.
True
What are NEURAL NETWORKS?
interconnected areas of the brain that can communicate with each other
*an extension of the idea of distributed processing > if many areas are involved in a particular type of cognition, they may be connected
What commonality do perceiving faces, remembering, and language share?
They all involve experiences that activate many separated brain areas.
What is the evidence regarding the areas activated in memory?
Many of these areas are linked either by direct neural connections or by being part of interconnected structures.
What are the 4 properties of neural networks?
- complex structural pathways that form the brain’s information highway
- within the structural pathways, there are functional pathways that serve different functions
- networks operate dynamically, mirroring the dynamic nature of cognition
- there is a resting state of brain activity > parts of the brain are active all the time, even when there is no cognitive activity
What is meant by STRUCTURAL CONNECTIVITY?
the brain’s “wiring diagram” created by nerve axons that connect different brain areas
What is TRACK-WEIGHTED IMAGING (TWI)?
a technique for determining connectivity in the brain that is based on detection of how water diffuses along the length of nerve fibres
What is meant by the term CONNECTOME?
a structural description of the network of elements and connections forming the brain OR
the writing diagram of neurons in the brain
What is meant by FUNCTIONAL CONNECTIVITY?
the extent to which the neural activity in the separate brain areas is correlated with each other
» if the responses of 2 brain areas are correlated with each other, this means they are functionally connected
What is resting-state fMRI?
The fMRI response measured when a person is at rest (not performing a cognitive task)
Developed by Bharat Biswal in 1995.
What is the seed location in resting-state fMRI?
The location in the brain associated with carrying out a specific task, determined using task-related fMRI.
What is the time-series response in resting-state fMRI?
The measure of how the fMRI response changes over time at the seed location.
What is the test location in resting-state fMRI?
Another brain location where resting-state fMRI is measured to assess connectivity.
How is functional connectivity determined in resting-state fMRI?
By calculating the correlation between the seed and test location responses using a complex mathematical procedure.
What does a high correlation in resting-state fMRI indicate?
High functional connectivity between the seed and test locations.
What does a low correlation in resting-state fMRI indicate?
Poor or no functional connectivity between the seed and test locations.
Which functional networks can be determined using resting-state fMRI?
- Visual
- Somato-motor
- Dorsal Attention
- Executive Control
- Salience
- Default mode
Is functional connectivity the same as structural connectivity?
No, functional connectivity and structural connectivity are not the same but are related.
True or False: Saying two areas are functionally connected means they directly communicate by neural pathways.
False.
Fill in the blank: Regions with high structural connectivity often show a high level of _______.
[functional connectivity]
What can cause two areas to have a high correlation in resting-state fMRI?
Both areas receiving inputs from another area.
What changes in the brain’s functional networks depend on conditions?
The flow of activity within and across the functional networks changes depending on conditions.
What does a simple experience like picking up a coffee cup involve?
Rapid switching and sharing of information between different functional networks (visual, attention, motor).
Can changes in brain connectivity happen slowly?
Yes, changes in connection can also happen slowly.
What is an example of functional connectivity changes throughout the day?
Functional connectivity changes in memory networks from morning to evening as memories are accumulated during the day and strengthened at night.
What changes have been reported in response to eating or drinking?
Some networks are strengthened and others are weakened when a person who fasted for a day resumed eating and drinking.
What is the DEFAULT MODE NETWORK?
A network discovered that responds when people are not engaged in tasks.
What was Gordon Schulman’s contribution to the discovery of the default mode network?
in 1997, noted fMRI instances where presentation of a task caused a decrease of activity in some areas of the brain, and stopping the task caused an increase in activity in the same areas
What was Marcus Raichle’s contribution to the development of the default mode network?
in 2001, proposed that the areas that decrease activity during tasks represent a “default mode” of brain function > brain function that occurs when the brain is at rest
What areas of the brain have been indicated in the default mode network?
frontal and parietal lobes
Fill in the blank: The flow of activity within and across the functional networks in the brain changes depending on _______.
[conditions]
True or False: The default mode network is active only when people are engaged in tasks.
False
What is the effect of an active default mode on people’s thinking?
“mind wandering”
decreases performance on tasks that require focused attention
this means that the DMN must have a purpose other than creating mind wandering and decreasing function
