From decision to action: Detailed modelling of frog tadpoles reveals neuronal mechanisms of decision-making and reproduces unpredictable swimming movements in response to sensory signals
Fig 5
Swimming initiation in response to trunk and head touch stimulation.
a-b. Neuronal activities on the left and right sides (2 upper and two lower panels, respectively). Central panels show spiking times where the vertical coordinate corresponds to the neuron rostro-caudal position. Other panels show the voltage traces of selected active neurons (one from sensory pathway and CPG populations plus three hexNs) and black arrows indicate the first dIN spike. (a) To mimic trunk touch 4 RBs are activated by a brief stimulation at time 0 (arrow, amplitude 0.3nA, duration 5ms). This starts swimming. (b) To mimic head touch, 4 sensory tSts fire one spike in response to stimulation at time 0 (arrow, amplitude 0.3nA, duration 5ms). c-d. Summary of statistics for simulated responses to high (low) trunk or head skin stimulation. (c) Simulation outputs are classified as swim, no swim, synchrony (sync) and one sided. Distribution of outputs is shown for each protocol as well as the percentages of swimming starting on the stimulated side. (d) Boxplots of swimming delays for each type of stimulation. Head skin touch (HT) is mimicked by stimulation of four sensory tSt neurons on the left side to fire once (Fig 5B). This excites tINs and rdlcs which fire once to excite hexNs on both sides and initiate reverberating firing. Short latency direct inputs from tINs and hexNs recruit left dINs which then excite left CPG neurons and initiate swimming.