Responses produced in tectal cells by nicotinic receptor activation. One of three responses was evoked in tectal cells by application of nicotine (nic; 100 μM): an increase in the frequency and amplitude of sPSCs (A1, 30% of total recordings), an increase in the frequency and amplitude of sPSCs and an inward membrane current (B1, 14% of total recordings) or just an inward membrane current (C1, 16% of total recordings). Nicotine did not evoke any response in 40% of the cells. Arrows in A1, B1 and C1 indicate areas of traces displayed at a faster time scale prior to drug application (A2, B2 and C2) and during the peak period of the nicotine response (A3, B3 and C3).