Uncertainty, Neuromodulation, and Attention

Neuron : Uncertainty, Neuromodulation, and Attention

Haven’t read this article from Peter Dayan’s lab yet but some interesting Bayesian modeling implicating acetylcholine as a signal of expected uncertainty and norepinephrine as a signal of unexpected uncertainty.


Uncertainty in various forms plagues our interactions with the environment. In a Bayesian statistical framework, optimal inference and prediction, based on unreliable observations in changing contexts, require the representation and manipulation of different forms of uncertainty. We propose that the neuromodulators acetylcholine and norepinephrine play a major role in the brain’s implementation of these uncertainty computations. Acetylcholine signals expected uncertainty, coming from known unreliability of predictive cues within a context. Norepinephrine signals unexpected uncertainty, as when unsignaled context switches produce strongly unexpected observations. These uncertainty signals interact to enable optimal inference and learning in noisy and changeable environments. This formulation is consistent with a wealth of physiological, pharmacological, and behavioral data implicating acetylcholine and norepinephrine in specific aspects of a range of cognitive processes. Moreover, the model suggests a class of attentional cueing tasks that involve both neuromodulators and shows how their interactions may be part-antagonistic, part-synergistic.

2 thoughts on “Uncertainty, Neuromodulation, and Attention

  1. I am sorry, but I cannot resist the similarity to one of my favorite Rumsfeldisms:

    As we know,
    There are known knowns.
    There are things we know we know.
    We also know
    There are known unknowns.
    That is to say
    We know there are some things
    We do not know.
    But there are also unknown unknowns,
    The ones we don’t know
    We don’t know.

    —Feb. 12, 2002, Department of Defense news briefing

    Nice post; do you really think that the mechanism is that cut-and-dry, however? Curious to know your thoughts.


  2. I’m with Dan on this one. I can kinda get behind the idea of dopamine as a signal for reward prediction error, but only really as a metaphor for what it is actually doing (signalling which synapses to strengthen and weaken). If noradrenaline signalled “unexpected uncertainty” then wouldn’t stimulants like cocaine/amphetamine, which release huge amounts of noradrenline, leave people feeling unexpectidly uncertain? (“Man that last line of blow was so good, but for some reason, I feel very unsure”… maybe not quite). Furthermore, what would the physiological consequences of uncertainty be?

    Also, I don’t understand how “Acetylcholine signals expected uncertainty”. Striatal cholinergics, as far as I am aware, behave just as dopaminergics do, in regards to the RESPOND to unexpected rewards, or initially the cues that signal a reward. Though in the case of striatal cholinergics, there response is to STOP firing.

    But then I see the author is talking about the cortex… might wanted to put that in the abstract there buddy. :/


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