Narrow Versus Wide Tuning Curves: What’s Best for a Population Code?

Neurophysiologists are often faced with the problem of evaluating the quality of a code for a sensory or motor variable, either to relate it to the performance of the animal in a simple discrimination task or to compare the codes at various stages along the neuronal pathway. One common belief that has emerged from such studies is that sharpening of tuning curves improves the quality of the code, although only to a certain point; sharpening beyond that is believed to be harmful. We show that this belief relies on either problematic technical analysis or improper assumptions about the noise. We conclude that one cannot tell, in the general case, whether narrow tuning curves are better than wide ones; the answer depends critically on the covariance of the noise. The same conclusion applies to other manipulations of the tuning curve profiles such as gain increase

Multisensory spatial representations in eye-centered coordinates for reaching

Humans can reach for objects with their hands whether the objects are seen, heard or touched. Thus, the position of objects is recoded in a joint-centered frame of reference regardless of the sensory modality involved. Our study indicates that this frame of reference is not the only one shared across sensory modalities. The location of reaching targets is also encoded in eye-centered coordinates, whether the targets are visual, auditory, proprioceptive or imaginary. Furthermore, the remembered eye-centered location is updated after each eye and head movement. This is quite surprising since, in principle, a reaching motor command can be computed from any non-visual modality without ever recovering the eye-centered location of the stimulus. This finding may reflect the predominant role of vision in human spatial perception

Differential preservation of anthracological material and mechanical properties of wood charcoal: an experimental approach of fragmentation

National audienceDifferential preservation of anthracological material and mechanical properties of wood charcoal: an experimental approach of fragmentatio

Narrow Vs Wide Tuning Curves: What's Best for a Population Code?

Neurophysiologists are often faced with the problem of evaluating the quality of a code for a sensory or motor variable, either to relate it to the performance of the animal in a simple discrimination task, or to compare the codes at various stages along the neuronal pathway. One common belief that has emerged from such studies is that sharpening of tuning curves improves the quality of the code, although only to a certain point beyond which further sharpening is believed to be harmful. We show that this belief relies on either problematic technical analysis or improper assumptions about the noise. We conclude that one cannot tell, in the general case, whether narrow tuning curves are better than wide ones; the answer depends critically on the covariance of the noise. The same conclusion applies to other manipulations of the tuning curve profiles such as gain increase