Extended Data Figure 2: Morphologies of neurons in the proximal antennal protocerebrum.

Images are z projections of coronal sections (dorsal is up). The soma remains sealed to the patch pipette at the end of each recording, and so the soma and the proximal part of the primary neurite are not present in the reconstructed morphologies; they are indicated schematically (soma with a black ball and primary neurite with a thick black line). Morphologies shown here were representative of all filled examples of the same neuron type (except as noted below). Regions are colour-coded according to the key in f. a, A fast-cool-PN. These neurons have dendrites in the proximal antennal protocerebrum and axons projecting to two regions of the lateral protocerebrum (posterior lateral protocerebrum and posterior slope). Some fast-cool-PNs arbourized unilaterally (rather than bilaterally) in the proximal antennal protocerebrum; we pooled data from both morphologies because their physiological properties were indistinguishable. b, A slow-cool-PN. These neurons have dendrites in the ipsilateral proximal antennal protocerebrum and axons projecting to a subregion of the calyx of the mushroom body. This morphology has been described previously³⁶ (that study called this neuron a ‘transverse antennal lobe projection neuron’). c, A warm-PN. These neurons have dendrites in the ipsilateral proximal antennal protocerebrum and axons projecting to two regions of the lateral protocerebrum (posterior lateral protocerebrum and posterior slope). d, A warm–cool-PN. These neurons have dendrites in both the ipsi- and contralateral proximal antennal protocerebrum, as well as the ventral-posterior margin of the antennal lobe. Their axons project to two regions of the lateral protocerebrum (posterior lateral protocerebrum and posterior slope). e, Two GABAergic LNs. All LNs we encountered in this study were bilateral. We define an LN here as a neuron that does not extend processes into any region except the proximal antennal protocerebrum (and the midline commissure that links the right and left copies of this brain region). Most LNs arbourized broadly within the posterior antennal protocerebrum and so are well-positioned to mediate cross-talk between warm and cool pathways. f, Locations of colour-coded brain regions in a coronal section through the brain.