Chapter 2: Cognitive Neuroscience Flashcards
Cognitive Neuroscience
field concerned with studying the neural basis of cognition
Levels of Analysis
a topic can be understood by studying it at a number of different levels of a system
Neurons
cell that is specialized to receive and transmit information in the nervous system
Nerve Net
a network of continuously interconnected nerve fibers (as contrasted with neural networks, in which fibers are connected by synapses)
Neuron Doctrine
the ides that individual cells called neurons transmit signals in the nervous system, and that these cells are not continuous with other cells as proposed by nerve net theory
Cell Body
part of a cell that contains mechanisms that keep the cell alive, in some neurons the cell body and the dendrites associated with it receive information from other neurons
Dendrites
structures that branch out from the cell body to receive electrical signals from other neurons
Axons
part of the neuron that transmits signals from the cell body to the synapse at the end of the axon
Synapse
space between the end of an axon and the cell body or dendrite of the next axon
Neural Circuits
group of interconnected neurons that are responsible for neural processing
Receptors
specialized neural structures that respond to environmental stimuli such as light, mechanical stimulation, or chemical stimuli
Microelectrodes
small wires that are used to record electrical signals from single neurons
Recording Electrode
when used to study neuronal functioning, a very thin glass or metal probe that can pick up electrical signals from single neurons
Reference Electrode
used in conjunction with a recording electrode to measure the difference in charge between the two
reference electrodes are generally placed where the electrical signal remains constant, so any change in charge between the recording and reference electrodes reflects events happening near the tip of the recording electrode
Resting Potential
difference in charge between the inside and outside of a nerve fiber when the fiber is at rest (no other electrical signals are present)
Nerve Impulse
an electrical impulse that is propagated down the length of an axon (nerve fiber)
Action Potential
propagated electrical potential responsible for transmitting neural information and for communication between neurons, typically travel down a neuron’s axon
Neurotransmitter
chemical that is released at the synapse in response to incoming action potential
Principle of Neural Representation
everything a person experiences is based on representations in the person’s nervous system
Feature Detectors
neurons that respond to specific visual features, such as orientation, size, or the more complex features that makeup environmental stimuli
Experience-Dependent Plasticity
a mechanism that causes an organisms neurons to develop so they respond best to the type of stimulation to which the organism has been exposed
Visual Cortex
area in the occipital lobe that receives signals from the eyes
Temporal Lobe
the lobe on the side of the brain that contains mechanisms responsible for language, memory, hearing, and vision
Hierarchy Processing
processing that occurs in a progression from lower to higher areas of the brain
Sensory Code
how neural firing represents various characteristics of the environment
Specificity Coding
the representation of a specific stimulus by the firing of neurons that respond only to that stimulus
an example would be the signaling of a person’s face by the firing of a neuron that responds only to that person’s face
Population Coding
neural representation of a stimulus by the pattern of firing of a large number of neurons
Sparse Coding
neural coding based on the pattern of activity in small groups of neurons
Localization of Function
location of specific functions in specific areas of the brain
for example, areas have been identified that are specialized to process information involved in the perception of movement, form, speech, and different aspects of memory
Cerebral Cortex
the 3-mm-thick outer layer of the brain that contains the mechanisms responsible for higher mental functions such as perception, language, thinking, and problem solving
Cortical Equipotentially
the idea, popular in the early 1800s, that the brain operates as an invisible whole, as opposed to operating based on specialized areas
Broca’s Area
an area in the frontal lobe associated with the production of language, damage to this area causes Broca’s aphasia
Broca’s Aphasia
a condition associated with damage to Broca’s area, in the frontal lobe, characterized by labored ungrammatical speech and difficulty in understanding some types of sentences
Wernicke’s Area
area in the temporal lobe associated with understanding language
damage to this area causes Wernicke’s aphasia
Occipital Lobe
the lobe at the back of the brain that is devoted primarily to analyzing incoming visual information
Parietal Lobe
the lobe at the top of the brain that contains mechanisms responsible for sensations caused by stimulation of the skin and also some aspects of visual information
Frontal Lobe
the lobe in the front of the brain that serves higher functions such as thought, language, memory, and motor functioning
Prosopagnosia
condition caused by damage to the temporal lobe that is characterized by an inability to recognize faces
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
Functional Magnetic Resonance Imaging (fMRI)
a brain imaging technique that measures how blood flow changes in response to cognitive activity
Voxels
small cube-shaped areas in the brain used in the analysis of data from brain scanning experiments
Task-Related fMRI
the fMRI response that occurs in response to a specific cognitive task
Fusiform Face Area (FFA)
an area in the temporal lobe that contains many neurons that respond selectively to faces
Parahippocampal Place Area (PPA)
an area in the temporal lobe that contains neurons that are selectively activated by pictures of indoor and outdoor scenes
Extrastriate Body Area (EBA)
an area in the temporal cortex that is activated by pictures of bodies and parts of bodies, but not by faces or other objects
Multidimensional
the multidimensional nature of cognition refers to the fact that even simple experiences involve combinations of different qualities
Distributed Representation
occurs when a specific cognition activates many areas of the brain
Neuronal Networks
groups of neurons or structures that are connected together
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 fibers
Functional Connectivity
the extent to which the neural activity in separate brain areas is correlated with each other
Resting-State fMRI
the fMRI response recorded when a person is at rest (not involved in any cognitive tasks)
Resting-State Functional Connectivity
a method for determining functional connectivity that involves determining the correlation between the resting state fMRI in separated structures
Seed Location
the area of the brain associated with carrying out a specific cognitive or motor task that serves as the reference area in the resting-state functional connectivity method
Time-Series Response
the way the fMRI response changes over time
Test Location
when measuring resting-state functional connectivity, the activity of the test location is compared to the activity at the seed location to determine the degree of functional connectivity between the two locations
Default Mode Network
network of structures that are active when a person is not involved in specific tasks
What is cognitive neuroscience?
the study of physiological basis of cognition
involves an understanding of both the nervous system and the individual units that comprise that system
What are levels of analysis?
we do not examine topic of interest from a single perspective, but rather we look at them from multiple angles and different points of view
each “viewpoint” can add small amounts of information which, when considered together, leads to greater understanding
What are nerve nets?
early concept of interconnected neurons creating a nerve net, similar to a highway network
streets are connected without stop signs
this allows for almost nonstop, continuous communication of signals throughout the network
What is the neuron doctrine?
Ramon y Cajal
individual nerve cells transmit signals, and are not continuously linked with other cells
What are neurons?
cells specialized to receive and transmit information in the nervous system
each neuron has a cell body, an axon, and dendrites
What is a cell body?
contains mechanisms to keep cell alive
What is an axon?
tube filled with fluid that transmits electrical signal to other neurons
What are dendrites?
multiple branches reaching from the cell body, which receives information from other neurons
What are sensory receptors?
specialized to respond to information received from the senses
What is an action potential?
neuron receives signal from environment
information travels down the axon of that neuron to the dendrites of another neuron
How do you measure action potentials?
microelectrodes pick up electrical signal, placed near axon
size is not measured; it remains constant
the rate of firing is measured
low-intensity stimulus: slow firing
high-intensity stimulus: fast firing
What is the synapse?
space between axon of one neuron and dendrite or cell body of another
when the action potential reaches the end of the axon, synaptic vesicles open and release chemical transmitters
What are neurotransmitters?
chemicals that affect the electrical signal if the receiving neuron, cross the synapse and bind with receiving dendrites
What are excitatory neurotransmitters?
increases chance neuron will fire
What are inhibitory neurotransmitters?
decreases chance neuron will fire
What is the definition of the mind?
a system that creates representations of the world, so we can act on it to achieve goals
What is the principle of neural representation?
everything a person experiences is based on representations in the person’s nervous system
What are feature detectors?
neurons that respond best to a specific stimulus
What was the Hubel & Wiesel (1960s) research with visual stimuli in cats?
an experiment in which electrical signals are recorded from the visual system of an anesthetized cat that is viewing stimuli presented on the screen
the lens in front of the cat’s eye ensures that the images in the screen are focused in the cat’s retina
oriented bar, oriented moving bar, and short moving bar are the few types of stimuli that cause neurons in the cat’s visual cortex to fire
What is experience-dependent plasticity?
the structure of the brain changes with experience
kittens exposed to vertical-only stimuli over time could only perceive verticals in normal stimuli
demonstrated that perception is determined by neurons that fire to specific qualities of a stimulus
What is hierarchical processing?
when we perceive different objects, we do so in a specific order that moves from lower to higher areas of the brain
the ascension from lower to higher areas of the brain corresponds to perceiving objects that range from lower (simple) to higher levels of complexity
What is specificity coding?
representation of a stimulus by the firing of specifically tuned neurons specialized to respond only to a specific stimulus
What is population coding?
representation of a stimulus by the pattern of firing of a large number of neurons
What is sparse coding?
representation of a stimulus by a pattern of firing of only a small group of neurons, with the majority of neurons remaining silent
What is the localization of function?
specific functions are served by specific areas of the brain
cognitive functioning declines in specific ways when certain areas of the brain are damaged
cerebral cortex (3-mm-thick layer covering the brain) contains mechanism responsible for most cognitive functions
What are the primary receiving areas for the senses?
occipital lobe: vision
parietal lobe: touch, temperature, and pain
temporal lobe: hearing, taste, and smell
What is the frontal lobe?
coordination of information received from all senses
What is double dissociation?
when damage to one part of the brain causes function A to be absent while function B is present, and damage to another area causes function B to be absent while function A is present
allows us to identify functions that are controlled by different parts of the brain
What is positron emission tomography (PET)?
blood flow increases in areas of the brain activated by a cognitive task
radioactive tracer is injected into person’s bloodstream
measures signal from tracer at each location of the brain
higher signals indicate higher levels of brain activity
What is brain imaging?
subtraction technique measures brain activity before and during stimulation presentation
difference between activation determines what areas of the brain active during manipulation
How is localization demonstrated by brain imaging?
functional magnetic resonance imaging (fMRI)
measures neural activity by identifying highly oxygenated hemoglobin molecules
activity recorded in voxels (3-D pixels)
What are event-related potentials (ERP)?
neuron “firing” is an electrical event
measure electrical activity on the scalp and make inferences about underlying brain activity
averaged over a large number of trails to calculate ERPs
advantage: continuous and rapid measuremnts
disadvantage: does not give precise location
What is the fusiform face area (FFA)?
responds specifically to faces
damage to this area causes prosopagnosia (inability to recognize faces)
What is the Parahippocampal place area (PPA)?
responds specifically to places (indoor/outdoor scenes)
What is the extrastriate body area (EBA)?
responds specifically to pictures pf bodies and parts of bodies
What is the central principle of cognition?
most of our experience is multidimensional
What is distributed representation in the brain?
in addition to localization of function, specific functions are processed by many different areas of the brain
may seem to contradict the notion of localization of function, but the concepts are complementary
What are neural networks?
interconnected areas of the brain that communicate with each other
What is a connectome?
structural description of the network of elements and connections forming the human brain
What is structural connectivity?
the brain’s “wiring diagram” created by axons that connect brain areas
as unique to individuals and fingerprints
What is functional connectivity?
how groups of neurons within the connectome function in relation to types of cognition
determined by the amount of correlated neural activity in two brain areas
What are the dynamics of cognition?
the flow and activity within and across the brain’s functional networks change based on conditions
change within and across networks is constant
What is the default mode network?
mode of brain function that occurs when it is at rest (activation at rest is higher than at tasks)
e.g. mind wandering is higher than when you engage in the class
one of the brain’s largest networks
What is the Coglab for Brain Asymmetry?
this experiment uses a technique devised by Levy, Heller, Banich, & Burton (1983) for demonstrating differences between the hemispheres of a normal subject’s brain
the stimuli involve chimeric faces
a chimeric face is made by taking two different faces, dividing them in half, and combining the left side of one face with the right side of the other face to make a combined, chimeric, face
a right-handed observer will choose the chimeric face with the younger half on the left in terms of the viewpoint of the subject
left-handed people will not show as strong differences in choose the chimeric face
