Sophie Deneve | PubMed Health

PubMed2003

Basis functions for object-centered representations.

In an object-centered representation, the position of the subparts of an object are encoded with respect to a set of axes and an origin centered on the object. Several physiological and neuropsychological results support the existence of such representations in humans and monkeys. An explicit representation would involve neurons with invariant response properties in object-centered coordinates. We consider an alternative scheme using basis functions in which the cells have retinotopic receptive fields modulated by the orientation of the object and task-related signals. We show that this alternative is consistent with single-cell data, is computationally efficient, and accounts for object-centered hemineglect, a syndrome observed in humans after fronto-parietal lesions.

Algorithms↗

PubMed2002

A computational perspective on the neural basis of multisensory spatial representations.

We argue that current theories of multisensory representations are inconsistent with the existence of a large proportion of multimodal neurons with gain fields and partially shifting receptive fields. Moreover, these theories do not fully resolve the recoding and statistical issues involved in multisensory integration. An alternative theory, which we have recently developed and review here, has important implications for the idea of 'frame of reference' in neural spatial representations. This theory is based on a neural architecture that combines basis functions and attractor dynamics. Basis function units are used to solve the recoding problem, whereas attractor dynamics are used for optimal statistical inferences. This architecture accounts for gain fields and partially shifting receptive fields, which emerge naturally as a result of the network connectivity and dynamics.

Animals↗