Midterm 2: Chapter 2 Flashcards
The interaction of the signals of many neurons
Neural Processing
Electrical signals
Neurons
Contain mechanisms to keep the cell alive
Cell body
Branches out from the cell body to receive electrical signals from other neurons.
Dendrites
Filled with fluid that conducts/sends out electrical signals
Axon
Neurons specialized to respond to environmental stimuli.
Sensory receptors
Approximately -70 millivolts (mV), meaning the inside of the axon is negatively charged compared to the outside when it is not actively transmitting a signal.
Resting potential
Once the response is triggered, it travels all the way down the axon without decreasing in size; it enables neurons to transmit signals over long distances.
Propagated Response
What happens to action potentials depending on the intensity of the stimulus?
it remains the same size
What does changing the stimulus intensity affect?
the RATE of firing
The interval between the time one nerve impulse occurs and the next one can be generated in the axon.
Refractory Period
Action potentials that occur in the absence of stimuli from the environment.
Spontaneous Activity
Molecules that carry an electrical charge; created when molecules gain or lose electrons.
Ions
the ease with which a molecule can pass through the membrane and selective means that the fiber is permeable to one specific type of molecule but not to others.
Permeability
An increase in positive charge inside the neuron
Depolarization
The quick and steep depolarization from -70mV to +40mV during an action potential
Rising phase of the action potential
Small space between neurons
Synapse
Chemicals that are stored in structures called synaptic vesicles at the end of the sending neuron.
Neurotransmitters
Small areas on the receiving neuron that are sensitive to specific neurotransmitters.
Receptor Sites
What causes the triggering of a chemical process that causes a new electrical signal in the receiving neuron?
When an electrical signal reaches the synapse
Occurs when the neuron becomes depolarized, and thus, the inside of the neuron becomes more positive.
Excitatory Response
Why is depolarization an excitatory response?
It causes the charge to change in the direction that triggers an action potential.
Occurs when the inside of the neuron becomes more negative, or hyperpolarized.
Inhibitory Response
Why is hyperpolarization an inhibitory response?
It causes the charge inside the axon to move away from the level of depolarization.
How does a neuron’s firing decrease?
Inhibition becomes stronger, and excitation becomes weaker.
Refers to how neurons represent various characteristics of the environment
Sensory Coding
The notion of a specialized neuron that responds only to one concept or stimulus.
Specificity Coding
Can a particular neuron respond to the CONCEPT of a particular person?
YES
Occurs when a particular stimulus is represented by a pattern of firing of only a small group of neurons, with the majority of neurons remaining silent.
Sparse coding
Proposed that our experiences are represented by the pattern of firing across a large number of neurons.
Population coding
What did Franz Gall claim about the shape of a person’s skull?
There is a correlation between the shape of a person’s skull and their abilities and traits, which he called “mental faculties”: PHRENOLOGY.
The idea is that specific brain areas are specialized to respond to specific types of stimuli or functions; each specific area is called a module.
Modularity
Area of speech production
Broca’s area
Area in temporal lobe involved in understanding speech.
Wernicke’s area
What was Broca’s and Wernicke’s area evidence for?
Early evidence for modularity
What is a more controlled way in which modularity has been studied?
Recording brain responses in neurologically normal humans using brain imaging.
- Excellent for revealing brain structures, but doesn’t indicate neural activity.
- use magnets, radio waves, and a computer to create images of soft tissues in the body, such as organs and muscles.
MRI (magnetic resonance imaging)
- helps researchers determine how various types of cognition, or functions, activate different areas of the brain.
- takes advantage of the fact that blood flow increases in activated areas of the brain (hemoglobin).
- determines the relative activity of various areas of the brain by detecting changes in the magnetic response of the Hemoglobin.
- IT CAN’T RECORD ACTIVITY FROM INDIVIDUAL NEURONS.
fMRI (functional magnetic resonance imaging)
An idea proposed by Hinton is that the brain represents information in patterns distributed across the cortex, rather than in one single brain area.
Distributed Representation
What is an example of distributed representation?
How the brain responds to pain, you simultaneously experience the sensory component, emotional component, and reflexive motor component.
The road map of fibers connecting different areas of the brain.
Structural connectivity
The neural activity is associated with a particular function that is flowing through this structural network.
Functional connectivity
The structure of the brain is measured using _________.
MRI
The function of the brain is measured using _________.
fMRI
a technique that measures brain activity in response to experimental circumstances. It’s used to identify neural reactions to tasks
task-related fMRI
a brain imaging technique that measures spontaneous brain activity while a subject is at rest or sedated
resting-state fMRI
a philosophical question that explores the relationship between the mind and the body
Mind-body problem
