Ruling out and ruling in neural codes

Adam L. Jacobs, Gene Fridman, Robert M. Douglas, Nazia M. Alam, Peter E. Latham, Glen T. Prusky, Sheila Nirenberg

Research output: Contribution to journalArticlepeer-review

121 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)5936-5941
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number14
StatePublished - Apr 7 2009
Externally publishedYes


  • Bayesian
  • Ganglion cells
  • Ideal observer
  • Neural coding population coding

ASJC Scopus subject areas

  • General


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