Representative spontaneous neuronal activity exhibited by (A) immature and (B) mature cortical cultures recorded via MEA in control and following application of the mAChR agonist, OXO-M (10 μM). (i) 100 s of spontaneous neuronal activity occurring on a single channel, where the left and right asterisks indicate periods later expanded to show a long (ii) and short burst (iii) respectively. (iv) ~50 s of activity following application of OXO-M, showing occurrence of bursting and (iv.a) asynchronous mixed tonic and bursting activity types. (v) Expanded period indicated by asterisk in iv. (vi) Array-wide neuronal activity in control conditions and (vii) following addition of OXO-M. Note the appearance of burst events on several channels in OXO-M, in both mature and immature cultures.