Volume 9 Issue 4, April 2006

Volume 9 Issue 4

In a Bayesian model of human motion perception, a prior expectancy for slow speeds is combined with sensory information. Low contrast stimuli provide a weaker sensory signal, so the prior contributes more to perception. Fixating on the central point of this cover image elicits a stronger illusion of motion in the surrounding circles with higher contrast. In this issue, Stocker and Simoncelli show that the prior in human speed perception can be derived from psychophysical measurements. (pp 468 and 578)



Book Review

News and Views

  • News & Views |

    Antidepressants take a few weeks to act, and their effects can extend for months after the drugs are discontinued. Tsankova et al. suggest a possible molecular basis for these effects, by showing that stress and the antidepressant imipramine induce modifications of chromatin to produce more or less repressive states for gene expression.

    • Steven E Hyman
  • News & Views |

    Both menthol and cool temperatures activate the cation channel TRPM8, but whether they do so via distinct domains was unclear. A new paper shows that activation of TRPM8 by these two stimuli can be separated.

    • Craig Montell
  • News & Views |

    A Bayesian model of visual motion perception describes how the brain combines assumptions with evidence. A new study in this issue tests and expands the model, building connections between perception, the environment and neural responses.*

    • Matteo Carandini
  • News & Views |

    Traditional learning theory suggests that animals do not understand that actions cause their consequences. A new paper uses sophisticated behavioral experiments to conclude that rats are capable of causal reasoning.

    • Nicola Clayton
    •  & Anthony Dickinson

Brief Communications