## Section: New Results

### Neural fields theory

#### Neural fields with noise

Participants : Olivier Faugeras, James Inglis.

We extend the theory of neural fields which has been developed in a deterministic framework by considering the influence spatio-temporal noise. The outstanding problem that we here address is the development of a theory that gives rigorous meaning to stochastic neural field equations, and conditions ensuring that they are well-posed. Previous investigations in the field of computational and mathematical neuroscience have been numerical for the most part. Such questions have been considered for a long time in the theory of stochastic partial differential equations, where at least two different approaches have been developed, each having its advantages and disadvantages. It turns out that both approaches have also been used in computational and mathematical neuroscience, but with much less emphasis on the underlying theory. We present a review of two existing theories and show how they can be used to put the theory of stochastic neural fields on a rigorous footing. We also provide general conditions on the parameters of the stochastic neural field equations under which we guarantee that these equations are well-posed. In so doing we relate each approach to previous work in computational and mathematical neuroscience. We hope this will provide a reference that will pave the way for future studies (both theoretical and applied) of these equations, where basic questions of existence and uniqueness will no longer be a cause for concern. This work has appeared in the Journal of Mathematical Biology [19] .

#### A center manifold result for delayed neural fields equations

Participants : Romain Veltz, Olivier Faugeras.

Lemma C.1 in [83] is wrong. This lemma is used in the proof of the existence of a smooth center manifold, Theorem 4.4. An additional assumption is required to prove this existence. We spell out this assumption, correct the proofs and show that the assumption is satisfied for a large class of delay functions $\tau $. We also weaken the general assumptions on $\tau $.

This work has been accepted for publication in the SIAM Journal on Mathematical Analysis and is available as [37] .