Effects of scopolamine on the acquisition and expression of the conditioned response (CR).

<p>After 2 days of adaptation sessions (sp1–2), both saline–and scopolamine–treated mice underwent acquisition sessions for 7 consecutive days (acq1–7) followed by 3 days of expression sessions (exp1–3). (A) The left and middle panels represent the averaged CR frequency in both cued and non-cued trials. (a) Averaged data from cued trials (filled circles; n = 8) and non-cued trials (empty circles; n = 8) are illustrated for saline-injected control mice. (b) Averaged data from cued trials (filled circles; n = 8) and non-cued trials (empty circles; n = 8) are shown for scopolamine-injected mice. (B) The right panel represents the discrimination (%) to the CSs between the groups. Differences in discrimination percentage between cued and non-cued trials are plotted for the saline-treated (filled triangles) and scopolamine–treated mice (empty triangles). In panel A, the vertical axis represents the CR(%) frequency while the horizontal axis illustrates corresponding sessions and the vertical bars indicate the standard error of the mean. In panel B, the vertical axis represents discrimination to the CSs(%), while the horizontal axis illustrates corresponding sessions and the vertical bars indicate the standard error of the mean. sp, spontaneous session; acq, acquisition session; exp, expression session.</p

The stimulus sequence in the eyeblink serial feature-positive discrimination task.

<p>(A) Two kinds of trials were used in the task: cued trials and non-cued trials. In a cued trial, a light cue (2 s) was delivered 5 or 6s randomly before a tone conditional stimulus (CS), which co-terminated with a periorbital electrical shock unconditional stimulus (US). In a non-cued trial, the CS was presented alone, without the preceding light or US. Inter-trial intervals were randomized between 60 and 70 s. (B) The right panel shows the average of integrated EMGs in cued (black line) and non-cued trials (dotted line) of a mouse.</p

Modulation of CR dynamics in scopolamine–treated mice.

<p>Panel (A) represents the onset latency data for cued (filled circles) and non-cued (empty circles) trials, respectively. Panel (B) represents peak latency data for cued (filled circles) and non-cued (empty circles) trials, respectively. Panel (C) represents the CR peak amplitude data for cued (filled circles) and non-cued (empty circles) trials, respectively. In panels A and B, the vertical axis represents the average time (ms), while the horizontal axis illustrates corresponding sessions. In panel C, the vertical axis represents the CR peak amplitude (%), while the horizontal axis shows corresponding sessions. Vertical bars indicate the standard error of the mean.</p

Effects of scopolamine on EMG amplitudes.

<p>(A) The left and middle panels represent the averaged EMG amplitude overall valid trials. (a) Averaged data from cued trials (filled circles; n = 8) and non-cued trials (empty circles; n = 8) are illustrated for saline-injected control mice. (b) Averaged data from cued trials (filled circles; n = 8) and non-cued trials (empty circles; n = 8) are shown for scopolamine-injected mice. (B) The right panel represents ΔEMG amplitude values between cued and non-cued trials in both groups. Filled triangles represent ΔEMG amplitude values for the saline-treated group and empty triangles represent ΔEMG amplitude values for scopolamine–treated mice. In panel A, the vertical axis represents averaged EMG amplitudes, while the horizontal axis illustrates corresponding sessions, and the vertical bars indicate the standard error of the mean. In panel B, the vertical axis represents the ΔEMG amplitude values, while the horizontal axis illustrates corresponding sessions and the vertical bars indicate the standard error of the mean.</p

Modulation of CR dynamics in saline-treated mice.

<p>Panel (A) represents the onset latency data for cued (filled circles) and non-cued (empty circles) trials, respectively. Panel (B) represents peak latency data for cued (filled circles) and non-cued (empty circles) trials, respectively. Panel (C) represents the CR peak amplitude data for cued (filled circles) and non-cued (empty circles) trials, respectively. In panels, A and B, the vertical axis represents the average time (ms), while the horizontal axis illustrates corresponding sessions. In panel C, the vertical axis represents the CR peak amplitude (%), while horizontal axis shows corresponding sessions. Vertical bars indicate the standard error of the mean. The latencies of one control mouse in acquisition sessions 5–7 were excluded from the analysis because the average number of CR trials among non-cued trials was low (<1).</p