Fig. 4. Combinations of model LC units are required for behaviour.
a, We assess whether a group of model LC units are sufficient and necessary for behaviour if we inactivate all model LC units not in that group (middle, sufficient) or inactivate only that group of model LC units (right, necessary). b, We identify which model LC units contribute to forward velocity by cumulatively inactivating model LC units in a greedy manner (that is, inactivate the next model LC unit that, once inactivated, maintains the best prediction performance R2). The model LC units with the largest changes in performance (for example, LC13 and LC22) contribute the most. c, Results for cumulative inactivation for all six behavioural outputs; forward velocity (top) is the same as in b. Columns of each row are ordered based on the ordering of forward velocity (top). d, For a dynamic stimulus sequence of a fictive female only varying her size, we used our approach in a to identify the sufficient and necessary model LC units for the male forward velocity of the male (top). Red crosses denote inactivation; each square represents a model LC unit; colours match those in Fig. 3a. The active model LC units in the middle row are the same as those inactivated in the bottom row. e, Other example behavioural outputs and stimulus sequences to assess necessity and sufficiency. Same format as in d. For predicting Pslow song (right column), all but LC11 and LC25 were required, although not every LC type contributed as strongly. f, Results of cumulative inactivation for the dynamic stimulus sequences in d,e. Same format, colour legend and ordering of columns as in c.