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Fig. 1. Olfactory responses of Carassius auratus to changes in
environmental [Ca2+]. (A) Typical electroencephalogram (EEG)
recordings from the olfactory bulb (lower traces) and their integrated
activity (upper traces) in response to increases in [Ca2+] from
nominally zero (Ca2+-free AFW) to 0.1, 1.0 and 10 mmol
l-1 (horizontal bars). All three recordings were taken from the
same fish. (B) Semi-logarithmic plot of mean values (normalised data, see
Materials and Methods for details; N=6) showing the concentration
dependence of this effect (r2=0.98), and a Hill plot
fitted to the data giving an apparent EC50 of 0.6 mmol
l-1 [Ca2+] and a Hill coefficient of 0.8. The
environmental range of [Ca2+] normally encountered by Carassius
auratus and the plasma free [Ca2+] are also shown.