Cog Processes Ch. 2

Cognitive Neuro Science

Cognitive Neuroscience Definition

the study of the physiological basis of cognition

Levels of Analysis Definition

the idea that a topic can be studied in many different ways, with each approach contributing its own dimension to our understanding

How did early researchers examine brain tissue?

by dying the tissue with special stains that allowed the tissue to be observed

What is Nerve Net Theory?

an early theory for how brain tissue was connected in which it was belived that the brain tissue consisted of a network of continuously interconnected nerve fibers

Whose discoveries led to the Neural Doctrine?

Ramon y Cajal

Neural Doctrine Definition

individual cells transmit signals in the nervous system and that these cells are not continuous with other cells as previously believed (nerve net theory)

5 important contributions from Cajal

1. the nerve net is not continuous, but rather comprised of individual units

2. the individual units, called neurons, are the basis of the brain

3. there are gaps between the neurons called synapses

4. only specific neurons are connected, which create neural circuits

5. some neurons are receptors that intake specialized sensory information

Neural Circuit Definition

A group of interconnected neurons that are responsible for neural processing (Ex: the default mode network)

Receptors

specialized neural structures that respond to environmental stimuli

Who discovered that action potentials do not change shape ever?

Edgar Adrian

How did Edgar Adrian discover firing rate?

by examining action potentials on skin receptors when different pressure was applied; saw that the action potentials’ shapes stayed the same, but that their firing rate increased with more skin pressure

Resting Potential Definition

the neuron's resting state in which the inside of the neuron has a charge of -70mV, which is more negative that the outside of the neuron

Action Potential Definition

a nerve impulse that is transmitted down a neuron's axon, which leads to the neuron's electrical charge changing

Neurotransmitter Definition

chemicals that are released at the synapse in response to an action potential

What is The Principle of Neural Representation

that everything a person experiences is based on representations in the person's nervous system

What experiment did Hubel and Wiesel conduct?

in the 60s they presented cats with different visual stimuli to determine which neurons would fire in response to the stimuli

What were the findings of Hubel and Weisel’s Cat Experiment?

found that each neuron in the visual region of the cortex responded to specific types of stimulation (based on orientation, movement, length), which were termed feature detectors

Feature Detector Neuron Definition

neurons that respond to specific features such as orientation, movement, and length

What experiment did Blakemore and Cooper conduct?

brought kittens up in a space in which they only saw vertical black and white stripes on a wall

What were the findings from Blakemore and Cooper’s study?

the cats developed experience-based plasticity in which their brain development changed based on their experience; they only had neurons that could detect vertical lines, but not horizontal lines

about how much of the cortex does the visual network make up?

30%

What experiment did Charles Gross conduct?

presented different stimuli such as different shapes that were either light or dark to monkeys and recorded single neurons in their temporal lobes

What were the findings from Charles Gross’ monkey study?

found that some neurons responded to simple stimuli, however, others did not respond until they detected complex stimuli

Hierarchical Processing Definition

the process that occurs in progression from lower to higher areas of the brain, in which neurons progressively respond to more and more complex stimuli

What it The Problem of Sensory Coding

the problem of determining the neural representation for the senses

Sensory Code Definition

how neural firing represents various characteristics of the environment

Specificity Coding Definition

the representation of a specific stimulus by the firing of neurons that respond only to that stimulus

Examples of Specificity Coding

“the grandmother cell” and “the jennifer aniston cell”

Is Specificity Coding supported?

it is highly debated

Population Coding Definition

Neural representations of a stimulus by the pattern of firing of a large number of neurons

Sparse Coding Definition

when a particular object is represented by a pattern of firing of only a small group of neurons

Localization of Function Definition

when specific functions are performed by specific regions of the brain

What is Cortical Equipotentiality?

a theory from the early 1800s that assumed the brain operated as an indivisible whole

What is Broca’s Area and where is it?

an area in the temporal lobe associated with understanding language

What is Broca’s Aphasia?

a disorder caused by damage to Broca’s Area, characterized by laboured ungrammatical speech and difficulty in understanding some sentences

What is Wernicke’s Area and where is it?

an area in the temporal lobe associated with understanding language

What is Wernicke’s Aphasia?

a disorder caused by damage to Wernicke’s Area, characterized by difficulty understanding language and producing incoherent speech

Prosopagnosia Definition

the inability to recognize faces, caused by damage to the right lower temporal lobe (fusiform face area)

What must be found in order to determine if a specific brain region is specialized for a single function?

a double dissociation

What is Electroencephalography?

a brain imaging technique that uses electrodes put on the scalp to measure and record electrical activity of the brain

What is Magnetoencephalography?

a brain imaging technique that measures and records magnetic fields generated by neural activity

What in Near-Infrared Spectroscopy?

a brain imaging technique that measures and records changes in blood oxygenation by projecting near-infrared light throught the scalp and skull

What is Transcranial Magnetic Stimulation?

A brain imaging technique that uses magnetic coils oriented over specific brain regions to induce electrical currents that temporarily render that brain region unusable

What is Diffusion Tensor Imaging

a brain imaging technique that measures the diffusion of water across the brain

What is functional magnetic resonance imaging?

a brain imaging technique that measures how blood flow changes in response to cognitive activity

What is the fusiform face area?

an area in the temporal lobe that contains many neurons that respond selectively to faces

Where is the fusiform face area?

in the fusiform gyrus at the bottom of the temporal lobe

What is the Parahippocampal Place Area?

an area in the temporal lobe that contains neurons that are selectively activated by pictures of indoor and outdoor scenes

What is the Extrastriate Body Area?

an area in the temporal cortex that is activated by pictures of bodies and body parts, but not faces or other objects

What does it mean for out conscious experience to be multidimensional?

that even simple experiences involve combinations of many different qualities

Explain how looking at a face is multidimensional

we can perceive a face as a whole, but we simultaneously perceive emotion, where someone is looking, how the face is moving, the attractiveness of the face, and if the face is familiar, which all activate different areas of the brain

What is Distributed Representation

when a specific cognition activates many areas of the brain

Neural Network Definition

interconnected regions of the brain that can communicate with each other

Structural Connectivity Definition

the physical connections between different brain regions, established through neural pathways

How was structural connectivity discovered?

by staining thin slices of brain tissue to be able to see the neural pathways under a microscope

Connectome Definition

a map of the brain that details the complex network of neurons and their connections

Functional Connectivity

the extent to which the neural activity in separate brain areas is correlated with each other

What is the default mode network?

a network of structures that are functionally connected as they respond when a person is not involved in specific task

What cognitive process is the default mode network associated with?

mind wandering