Figure 6. The reciprocal short-term memories microcircuit of the mushroom body.

(A) Image of the reciprocal short-term memories microcircuit made of the MBON-γ5β′2a, PAM-β′2a, PPL1-γ2α′1, and MBON-γ2α′1 neurons – created using the Virtual Fly Brain software (Milyaev et al., 2012). (B) Schematic representation of the reciprocal short-term memories microcircuit (coloured) connected to the susceptible memories via the restrained mushroom body output neurons (MBONs). The responses of (C) the punishment-encoding charging dopaminergic neuron (DAN), $c_{\text{av}}$, the (D) attraction-driving restrained MBON, $r_{\text{at}}$, and (E) the reward-encoding charging DAN, $c_{\text{at}}$, generated by experimental data (left) and the model (right) during the olfactory conditioning paradigms of Figure 4D. Lightest shades denote the extinction, mid shades the unpaired, and dark shades the reversal phase. For each trial, we report two consecutive time-steps: the off-shock (i.e., odour only) followed by the on-shock (i.e., paired odour and shock) when available (i.e., odour B in acquisition and odour A in reversal phase); otherwise, a second off-shock time-step (i.e., all the other phases).

Figure 6—figure supplement 1. The responses of the neurons of the incentive circuit using the connections introduced so far of the susceptible memory (SM), restrained memory (RM), and reciprocal short-term memory (RSM) microcircuits.

The responses of (A) the punishment-encoding discharging dopaminergic neuron (DAN), $d_{\text{av}}$, (B) the attraction-driving susceptible mushroom body output neuron (MBON), $s_{\text{at}}$, (C) the avoidance-driving restrained MBON, $r_{\text{av}}$, (D) the reward-encoding charging DAN, $c_{\text{at}}$, (E) the reward-encoding discharging DAN, $d_{\text{at}}$, (F) the avoidance-driving susceptible MBON, $s_{\text{av}}$, (G) the attraction-driving restrained MBON, $r_{\text{at}}$, and (H) the punishment-encoding charging DAN, $c_{\text{av}}$, generated by experimental data (left) and the model (right) during the olfactory conditioning paradigms of Figure 4D. Lightest shades denote the extinction, mid shades the unpaired, and dark shades the reversal phase. The first row of responses (coloured pink) corresponds to responses associated with odour A, and the second (coloured yellow) to those associated with odour B. For each trial, we report two consecutive time-steps: the off-shock (i.e., odour only) followed by the on-shock (i.e., paired odour and shock) when available (i.e., odour B in acquisition and odour A in reversal phase); otherwise, a second off-shock time-step (i.e., all the other phases).

Figure 6—figure supplement 2. The KC→MBON synaptic weights of the neurons of the incentive circuit using the connections introduced so far of the susceptible memory (SM), restrained memory (RM), and reciprocal short-term memory (RSM) microcircuits.

The synaptic weights of (A) the attraction-driving susceptible mushroom body output neuron (MBON), $s_{\text{at}}$, (B) the avoidance-driving susceptible MBON, $s_{\text{av}}$, (C) the attraction-driving restrained MBON, $r_{\text{at}}$, and (D) the avoidance-driving restrained MBON, $r_{\text{av}}$, generated by experimental data (left) and the model (right) during the olfactory conditioning paradigms of Figure 4D. Lightest shades denote the extinction, mid shades the unpaired, and dark shades the reversal phase. The first row of weights (coloured pink) corresponds to Kenyon cells (KCs) associated with odour A, the second (coloured yellow) to KCs associated with odour B, and the third (coloured orange) to KCs associated with both odours. For each trial, we report two consecutive time-steps: the off-shock (i.e., odour only) followed by the on-shock (i.e., paired odour and shock) when available (i.e., odour B in acquisition and odour A in reversal phase); otherwise, a second off-shock time-step (i.e., all the other phases).