PAM dopaminergic neurons
systemLearning and memoryspeciesD. melanogaster3D view1 of 626 cellssources3
PAM neurons are dopaminergic neurons of the protocerebral anterior medial (PAM) cluster of the fruit fly brain. A group of them signals sugar reward to the medial lobes of the mushroom body, where appetitive odor memories form.
| Also known as | PAM cluster · Protocerebral anterior medial dopaminergic neurons |
|---|---|
| Region | Protocerebral anterior medial cluster; output to the medial lobes of the mushroom body |
| System | Learning and memory |
| In the display bundle | 1 of the 626 reconstructed neurons in the site’s MaleCNS display bundle, which shows 626 of the model’s 166,700 neurons: PAM05 1 |
What they are
A group of PAM dopaminergic neurons signals sugar reward. They are activated by sugar ingestion, more strongly when the fly is starved, and are required for the reinforcing property of sugar but not for reflexive responses to it (Liu et al., 2012).
Where they sit
Their output sites lie mainly in the medial lobes of the mushroom body (Liu et al., 2012). Each dopaminergic neuron type projects to one, or at most two, of the 15 mushroom body compartments (Aso et al., 2014).
What they do
Dopamine in insects had long been associated with aversive reinforcement; the PAM findings showed that a distinct subset of dopaminergic neurons signals reward (Liu et al., 2012).
Octopamine reinforces only short-term appetitive memory and does so through dopaminergic neurons. Directly activating an identified subset of mushroom-body-targeted dopaminergic neurons can substitute for sugar to form appetitive memory, even in flies lacking octopamine (Burke et al., 2012).