In neuroscience, a neurometric function is a mathematical formula relating the activity of brain cells to aspects of an animal's sensory experience or motor behavior.
Neurometric functions provide a quantitative summary of the neural code of a particular brain region.
In sensory neuroscience, neurometric functions measure the probability with which a sensory stimulus would be perceived based on decoding the activity of a given neuron or collection of neurons.
The concept was introduced to investigate the visibility of visual stimuli, by applying Detection theory to the output of single neurons of visual cortex.
[1] Comparing neurometric functions to psychometric functions (by recording from neurons in the brain of the observer) can reveal whether the neural representation in the recorded region constrains perceptual accuracy.