Neural code Flashcards
What does encoding mean
Changing the format of information, for example physical events into mental ones or changing sensory information into neural code
What are Electrophysiological recordings
Allow us to study a single neuron through an electron placed close to it.
What is the rate code
The number of action potentials per second used to encode information
What is a retinotopic map
The large array in which visual neurons are arranged
How does information detected by the neurons get coded into neural signals
Photoreceptors in the neurons convert images into electrical activity.
Interneurons (bipolar. horizontal and amacrine cells) collect this info and transmit it the retinal ganglion cells
Retinal ganglion cells send spikes/ action potentials to the brain.
What is ther difference between rods and cones
Rods: detect light and have low spatial resolution and so are used in the dark
Cones: detect colour and have high spatial resolution
Direct representation of sampling points
Neurons have low sensitivity as they only react to what is in front of them but high resolution.
As the stimulus size increases, the response of the neuron does not.
Many to one representation of sampling points
High sensitivity but low resolution
It will increase to an extent as if the size in increasing the response will also increase.
What is lateral inhibition
Where there response of a neuron is inhibited because of opponency where neighbouring neurons’ signals are balanced against it.
What happens to the response as the stimulus size increases when there is lateral inhibition
It will increase until a certain point where the receptors feeding neighbouring interneurons are stimulated.
This leads to inhibition and response continuously decreases.
Meaning there is an Optimum size for activation
What is the receptive field
The location in space where the presence of a visual stimulus can produce change in the response of a neuron
Which part of the receptive field is inhibitory and which is excitatory
Centre- excitatory
Surroundings- inhibitory
Why do neurons ignore larger uniform areas of light
Because we form images through looking at the change in light, where there is not change neurons provide a filter response and do not transmit it: redundancy reduction.
What is the difference between luminance and brightness
Luminance is the measured light and brightness is the perceived light.
What is size tuning
Receptive fields and cells have size tuning and therefore will respond best to certain sizes
