Figure 9.
MPH treatment. A, Optomotor responsiveness in wild-type flies treated with 0.5 mg/ml MPH (red histograms). Starved flies were transferred to drug-laced food and allowed to feed for 10 min, 3 h, or 24 h. Control flies were similarly transferred but to food without drug and tested 10 min later (Control1) or the next day (Control2). Flies chronically exposed to drug for 24 h were transferred back to normal food for 1–2 h and tested (Recovery). *p < 0.05, significantly different from controls by t test. n = 8 runs of 25–30 flies for each experiment. B, MPH (0.5 mg/ml) was administered acutely (2–4 h feeding on drug-laced food) to a panel of learning and memory mutants, as well as to flies with altered dopamine function [Th–Gal4 (Friggi-Grelin et al., 2003) × UAS–tnt, wherein dopaminergic neurons are silenced, or × UAS–eagΔ932, in which dopaminergic neurons are activated]. *p < 0.05, significantly different from controls (red vs blue bars) by t test. n = 8 runs of 25–30 flies for each experiment. C, Spectral analysis (0–5 Hz) of LFP activity in the brains of radish mutants treated to acute MPH (red line). Blue line, The same flies before treatment. Data are averages of z-scored spectrograms (n = 5 flies). *p < 0.05, significantly different within 0.3 Hz band range surrounding the peak, by t test. D, The effect of MPH on 20–30 Hz responsiveness (±SEM) to visual novelty in radish1 and wild-type flies. MPH feeding (red box) resulted in a significant novelty response in radish mutants (n = 5 flies), whereas radish mutants fed without the drug (blue box) show no response to novelty (n = 14). Wild-type responses to visual novelty were similar with and without MPH (n = 4 and 6 flies, respectively). *p < 0.05 by t test of means for either competing object. A visual explanation of how these data were calculated is in supplemental Methods 1 (available at www.jneurosci.org as supplemental material).