Neuronal noise

Neuronal noise is the term that describes random activity of neurons that presumably is not associated with encoding of behaviorally relevant variables. Many neuroscientists consider neuronal noise a factor that limits the capacity of information processing by the brain. Thus, Patrick Wilken and colleagues have suggested that neuronal noise is the principal factor that limits the capacity of visual short-term memory. Investigators of neural ensembles, and especially those who support the theory of distributed processing, propose that large neuronal populations effectively decrease noise by averaging out the noise in individual neurons.

Some investigators have shown experimentally and in models that neuronal noise is a possible mechanism to facilitate neuronal processing. The presence of neuronal noise (or more specifically synaptic noise) confers to neurons more sensitivity to a broader range of inputs, it can equalize the efficacy of synaptic inputs located at different positions on the neuron, and it can also enable finer temporal discrimination (see details in the "High-conductance state" article in Scholarpedia).

The external noise paradigm is used to test the presence or absence of neural noise. According to this paradigm, external noise should multiplicatively increase the amount of internal noise in the central nervous system. Researchers add visual or auditory external noise to a stimuli, and measure how it affects reaction time or the subject's performance. If performance is more inconsistent than without the noise, the subject has internal noise.

External links

• Neuronal Noise article in Scholarpedia
• High-Conductance State article in Scholarpedia