e., the values below zero are set as zero. Dynamic clamp recordings were carried out according to (Sharp et al., 1993, Chance et al., 2002 and Nagtegaal and Borst, 2010). The current injected in dynamic clamp was calculated on-line by a custom-written LabVIEW routine

and controlled by National Instrument Interface: I(t)=Ge(t)∗(Vm(t)−Ee),withoutinhibition; I(t)=Ge(t)∗(Vm(t)−Ee)+Gi(t)∗(Vm(t)−Ei),withinhibition. www.selleckchem.com/products/fg-4592.html The time-dependent Ge and Gi were generated by the computer according to the same function as shown above, and the difference in onset delay between excitation and inhibition was set as 50 ms. Ee and Ei were set as 0 mV and −70 mV, respectively. The membrane potential Vm was sampled at 5 kHz. Measurements of Vm were corrected off-line for the voltage drop on the uncompensated, residual series resistance (15–20 MΩ). The corrected Vm was only slightly different from the recorded Vm (data not shown). This work was supported by grants to H.W.T. from the US National Institutes of Health (EY018718 and EY019049). L.I.Z. is a Searle Scholar and Packard Fellow and was also supported

by the National Institute of Health (DC008983, DC008588). “
“In 1991, Leroy Burrell set a world record for the 100 m dash with a spectacular time of 9.90 s, stunning the prerace favorite Carl Lewis, who finished second with a time PF-02341066 molecular weight of 9.93 s. It was later noted, however, that Burrell was not the faster runner. Rather, his reaction time to the gun that marked the start of the race was much shorter than Lewis’s: a hair-trigger 117 ms against a relatively oxyclozanide lethargic 166 ms. Without this difference, Lewis would have won handily. Why was Carl Lewis so much slower than Leroy Burrell to start the race that day? Of course, nonathletes also often prepare movements in anticipation of events: while preparing to swat a fly, to press

a car accelerator when a traffic light turns green, or to select the appropriate button while playing a video game. Sometimes we are slow in reacting and sometimes we move before we are fully ready. This inability to precisely time the onset of a movement can often be extremely frustrating. What is the cause of this imprecision? Presumably, it is related to the operation of planning and executing movements. Voluntary movements are believed to be “prepared” before they are executed (e.g., Wise, 1985). Important evidence for this belief comes from behavioral tasks in which a delay period separates a stimulus instructing the goal of a reaching movement from a subsequent “go” cue. Reaction time (RT) is the time elapsed from the go cue until movement onset in these delayed-reach tasks, and RT is shorter when delays are longer (e.g., Rosenbaum, 1980 and Riehle and Requin, 1989). This suggests that a time-consuming preparatory process is given a head start by the delay period.