, 2008). In this respect, delay activity could be thought of as the response function of the network, rather than active maintenance of a static firing state. Here, we highlight short-term synaptic dynamics as an attractive putative mechanism for rapid adaptive coding Selleckchem INK1197 in PFC (see also Buzsáki, 2010; Deco et al., 2010). However, other phenomena
that systematically shift the response properties of a population could also contribute to adaptive coding. For example, temporary activity-dependent changes in membrane potentials could also shift the tuning profile of the network (Buonomano and Maass, 2009). Moreover, a systematic shift in the baseline activity state of the network could reroute processing
via conditional logic gates (McCulloch and Pitts, 1943) and/or exploiting nonlinear dynamics (Izhikevich, 2007). Finally, neural synchrony might be especially important for temporary shifts in effective connectivity (Fries, 2009). Phase synchrony has been implicated in WM (Axmacher et al., 2010; Buschman et al., 2011; Fell and Axmacher, 2011), and a recent study has further shown how rapid configuration of synchronized networks in PFC is specific to different rules states (Buschman et al., 2012). These mechanisms might also PD173074 ic50 be able to implement the functional change we describe here—a context-dependent shift in network dynamics, altering the mapping of sensory inputs to final behavioral decisions. Subjects were two male rhesus monkeys (Macaca mulatta), weighing 11 and 12 kg. All experimental procedures were approved by the UK Home Office and were in compliance with the guidelines of the European Community for the care and use of laboratory animals (EUVD, European Union directive 86/609/EEC). The cued target detection task is schematized in Figure 1B. Each trial commenced with a 500 ms baseline
period, during which the monkey held fixation on a red central fixation point accompanied by two dim gray circles (location markers) 6° to left and right on the horizontal meridian. Next, Sclareol one of three cue stimuli was presented for 500 ms at either the left or right (randomized) location marker. The cue determined the spatial location of all subsequent stimuli within that trial and also the direction of the eventual saccade response at the end of the trial. Most importantly, the cue identity also instructed which choice stimulus would be the target stimulus for the current trial. During initial training sessions, monkeys learned to associate three specific cue stimuli with three specific target stimuli. An additional stimulus served as a neutral nontarget item. All pictures were randomly drawn from the same set of images (2° × 2°). New stimulus pairs and neutral pictures were occasionally introduced and maintained for a number of sessions.