The normalization model
is an influential model of responses of
neurons
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...
in
primary visual cortex
The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and ...
.
David Heeger developed the model in the early 1990s,
and later refined it together with
Matteo Carandini
Matteo Carandini (born 1967) is a neuroscientist who studies the visual system. He is currently a professor at University College London, where he co-directs thCortical Processing Laboratorywith Kenneth D Harris.
He studies the visual cortex at ...
and
J. Anthony Movshon.
The model involves a divisive stage. In the numerator is the output of the classical
receptive field
The receptive field, or sensory space, is a delimited medium where some physiological stimuli can evoke a sensory neuronal response in specific organisms.
Complexity of the receptive field ranges from the unidimensional chemical structure of od ...
. In the denominator, a constant plus a measure of local stimulus
contrast. Although the normalization model was initially developed to explain responses in the primary visual cortex, normalization is now thought to operate throughout the visual system, and in many other sensory modalities and brain regions, including the representation of odors in the olfactory bulb,
[ ] the modulatory effects of visual attention, the encoding of value, and the integration of multisensory information. It has also been observed at subthreshold potentials in the hippocampus.
[ ] Its presence in such a diversity of neural systems in multiple species, from invertebrates to mammals, suggests that normalization serves as a canonical neural computation.
Divisive normalization reduces the redundancy in natural stimulus statistics and is sometimes viewed as an implementation of the
efficient coding principle. Formally, divisive normalization is an
information-maximizing code for stimuli following a
multivariate Pareto distribution In statistics, a multivariate Pareto distribution is a multivariate extension of a univariate Pareto distribution.
There are several different types of univariate Pareto distributions including Pareto distribution#Pareto types I–IV, Pareto Types ...
.
References
Visual perception
{{neuroscience-stub