van Essen et al. Mefloquine induced motor deficits Figure 1 | Dart throwing precision is not affected by the intake of mefloquine. (A) Schematic representations of two arms at the time of releasing the dart. Vertical throwing precision is more complex than horizontal throwing precision; it depends more on the moment of release and the speed of the throw. (B) Participants threw darts at a dartboard and for each throw the horizontal (Ex) and vertical deviations (Ey) from the center of the bull’s eye were determined. (C)The vertical and horizontal precision were not altered by the intake of mefloquine (n = 9). Under both conditions, the horizontal component of the throw is more precise than the vertical component (*both p < 0.05, n = 9, t test). (D)The normalized vertical deviation from the target (n = 9) and (e) the normalized standard deviation of vertical deviation from the target (n = 9) were not affected by the intake of mefloquine. Blue bars indicate mean + SEM (error bar) before mefloquine intake and red bars indicate mean + SEM (error bar) 24 h after mefloquine intake. The participants were explicitly instructed not to guess. Due to the involvement of the IO in this task and the temporal structure of the task, we would expect more errors in discriminating the rhythms after the use of mefloquine. Relfex blinking Participants were subjected to reflex blinking and eye-blink condi- tioning procedures. Eye blinks were recorded with the use of mag- netic distance measurement technique as described by (Koekkoek et al., 2002; Smit et al., 2008). Briefly, a magnetoresistive sensor was attached at the rim of the orbit below the right lower eyelid, while a small gold plated neodymium magnet was attached to the tarsal portion of the right upper eyelid (Figure 3A). The signal was amplified by a pre-amplifier close to the sensor and further amplification could be adjusted per subject. The signal was digi- tized (1000 Hz) using National Instruments hardware. A custom made LabView (National Instruments, Austin, TX, USA) script controlled the monitoring of eyelid movement, presentation of the stimuli and capturing of data on disk. Via the puff nozzle, an air puff (unconditioned stimulus: US) was directed to the cornea close to the outer canthus of the eye at a distance of about 15 mm. The apparatus served to deliver a 20-ms air-puff with an intensity of 10–50 PSI at the source. The intensity and duration were manually adjusted to elicit a single blink reflex (unconditioned response: UR). www.frontiersin.org November 2010 | Volume 4 | Article 191 | 3