Amyloid beta (Aβ) inhibits spontaneous network activity in the olfactory bulb (OB) of mice and rats.

<p>A, Representative recordings of the OB spontaneous network activity in slices, filtered at highpass = 0.5 Hz and lowpass = 1.5 KHz, obtained from 8-week-old mice in control conditions (upper trace), after 60 min of Aβ exposure (middle trace), and after 30 min of washout (lower trace). B, Averaged power spectra (± standard error; shaded area) of the slices under the three experimental conditions shown in A. Note that OB spontaneous network activity includes a broad variety of frequencies and that Aβ application produces a generalized and reversible reduction of the power without preferentially affecting any frequency range. C, Quantification of the power of OB network activity (as % of control) for different frequency bands (theta, beta, and gamma) for the experimental conditions represented in A. Note that Aβ reversibly reduces the power of the OB network activity to the same degree for all frequencies. D, Time-course of Aβ-induced inhibition of OB network activity, as % of control, over a frequency range of 1 to 50 Hz, and its washout. E, Comparison of Aβ-induced inhibition of OB network activity and its washout recorded in slices obtained from mice and rats. Note that the phenomenon is identical in slices obtained from both species. * Denotes a significant difference (p < 0.05) relative to the control (n = 7).