Chapter 2-cognitive Neuroscience Flashcards
Cognitive Neuroscience
- the study of the physiological basis of cognition
- involves an understanding of the nervous system and the individual units that comprise that system
Nerve net
Early concept of interconnected neurons creating a nerve net (similar to a highway network)
This allows for almost non stop continuous communication of signals throughout the network
Neuron doctrine
- Contradicts the nerve net
- Ramon y Cajal
- individual nerve cells transmit signals and are not continuously linked with other cells
Neurons
Cells specialized to receive and transmit information in nervous system
Cell body
Contains mechanisms to keep cell alive
Axon
Tube filled with fluid that transmits electrical signal to other neurons
Dendrites
Multiple branches reaching from the cell body, which receives information from other neurons
Sensory receptors
Specialized to respond to information received from the senses
Action potential
- Neuron receives signal from environment
- information travels down the axon of that neuron to the dendrite of another neuron
- all or none propagation
Measuring action potentials
- microelectrodes pick up electrical signal
- placed near axon
Measuring action potentials
- size is not measured: it remains consistent
- the rate of firing is measured:
Low intensity stimulus: slow firing
High intensity stimulus: fast firing
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 neurotransmitters
Neurotransmitters
Chemicals that affect the electrical signal of the receiving neuron, cross the synapse and bind with the receiving dendrites
Excitatory neurotransmitter
Increases chance neuron will fire
Inhibitory neurotransmitter
Decreases chance neuron will fire
Definition of the mind
A system that creates representations of the world, so that we can act on it to achieve goals
Principle of neural representation
Everything a person experiences is based on representations in the person’s nervous system
Feature detectors
Huber and Wiesel research with visual stimuli in cats
Feature detectors are neurons that respond best to a specific element
Experience-dependent plasticity (feature detectors)
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
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
Specificity coding (grandma cell)
Representation of a stimulus by the firing of specifically tuned neurons specialized to respond only to a specific stimulus
Population coding
Representation of a stimulus by the pattern of firing of a large number of neurons
All neurons fire but in different patterns
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
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