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Ruling out and ruling in neural codes.

ABSTRACT: The subject of neural coding has generated much debate. A key issue is whether the nervous system uses coarse or fine coding. Each has different strengths and weaknesses and, therefore, different implications for how the brain computes. For example, the strength of coarse coding is that it is robust to fluctuations in spike arrival times; downstream neurons do not have to keep track of the details of the spike train. The weakness, though, is that individual cells cannot carry much information, so downstream neurons have to pool signals across cells and/or time to obtain enough information to represent the sensory world and guide behavior. In contrast, with fine coding, individual cells can carry much more information, but downstream neurons have to resolve spike train structure to obtain it. Here, we set up a strategy to determine which codes are viable, and we apply it to the retina as a model system. We recorded from all the retinal output cells an animal uses to solve a task, evaluated the cells' spike trains for as long as the animal evaluates them, and used optimal, i.e., Bayesian, decoding. This approach makes it possible to obtain an upper bound on the performance of codes and thus eliminate those that are insufficient, that is, those that cannot account for behavioral performance. Our results show that standard coarse coding (spike count coding) is insufficient; finer, more information-rich codes are necessary.

SUBMITTER: Jacobs AL

PROVIDER: S-EPMC2657589 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature

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Ruling out and ruling in neural codes.

Jacobs Adam L AL Fridman Gene G Douglas Robert M RM Alam Nazia M NM Latham Peter E PE Prusky Glen T GT Nirenberg Sheila S

Proceedings of the National Academy of Sciences of the United States of America 20090318 14

The subject of neural coding has generated much debate. A key issue is whether the nervous system uses coarse or fine coding. Each has different strengths and weaknesses and, therefore, different implications for how the brain computes. For example, the strength of coarse coding is that it is robust to fluctuations in spike arrival times; downstream neurons do not have to keep track of the details of the spike train. The weakness, though, is that individual cells cannot carry much information, s ...[more]

PMID: 19297621

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Ruling out and ruling in neural codes.

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Ruling out and ruling in neural codes.

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