Task 3 Brains and Computers Flashcards
Connectionism
An artifical intelligence appraoch which models cognition in artifical neural networks.
Local representation
Nodes in a neural network each represent one representational element.
Distributed representation
Nodes in a neural network each represent seperate elements of a representational element.
Graceful degradation
Network breaks down only slowly as damage increases
- small damage has no effect on network performance
Activation functions
The function of a node in a neural network that determines the activity of a neuron. (Linear, Threshold linear, Binary, Sigmoid)
Output functions
The function of a node in a neural network that determines the output a node sends forward
Transfer functions
The function of a node in a neural network that determines the transformation on the input to create an output
Multilayerd network
A neural network that contains one hidden layer, and are useful for higher level computations
Deep neural network
A neural network that contains multiple hidden layers, and are useful for higher level computations
Feedforward network
A neural network in which information flows in one direction throught the network
Recurrent network
A neural network which exhibits temporal dynamic behaviour by sending its output back into itself as well as to the next layer
Backpropagation
- The delta rule applied to multi-layer networks propagates the error back through the neural network
- To find total error of neuron in hidden layer
Delta rule
- Method used to calculate the difference between actual and desired output (error) and change the weights accordingly (That the error equals 0)
- Gradual changes with each learning trial
Gradient descend learning
An optimization algorithm used in machine learning to find the optimal weight levels of nodes in a neural network. (Only find local optimum)
Neural network
An artificial neural network, composed of artificial neurons or nodes.
BCI
Brain Computer Interface, is a direct communication pathway between an enhanced or wired brain and an external device
- Changing brain activation
- -> Enhancing normal brain function
- -> Neurofeedback therapy - Compensation of lost motor function
- -> Communication
- -> Device control
Invasive BCI
Attach wires to the brain (open scalp)
Non-invasive BCI
EEG, MEG, fMRI, PET etc.
Neurofeedback
Technique in which subjects can see their own brain activity (fmri and eeg) and then actively try to change this brain activity
BCI system
- Signal Acquisition
- Signal Processing
- Feature Extraction
- Translation Algorithm
- -> Device commands
