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(This hierarchical progression, from V1 to IT, is also part of the abovementioned object recognition model of Deco and Rolls, 2004). In motor control, the view of behavior as hierarchically organized, with goals and performance being represented and controlled at different hierarchical levels, goes back at least to Bernstein in the 1940s (Latash and Latash, 1994), and functional models of behavior built on this type of assumption have been able to generate complex behaviors with concurrent goals at different time scales (e.g., tea-making; cf. Figure ?Figure1B),1B), while at the same time reproducing typical mistakes observed during such behavior (Cooper and Shallice,  2000, 2006; Crump and Logan, 2010). In line with this type of model,  a single pointwise electrical stimulation of primary motor [http://www.selleckchem.com/products/Erlotinib-Hydrochloride.html Erlotinib purchase] cortex can trigger seemingly goal-directed movements, such as reaching for a specific location in space ((Graziano et al., 2005; Graziano and Aflalo, 2007), interpretable as low-level chunks or schemata (Norman and Shallice, 1986) for use in the construction of more complex, compound overt activity. Neuronal activity in more rostral areas of frontal cortex, including prefrontal cortex (PFC), have been repeatedly shown to correlate with maintenance of goals for and control of such higher-level activity, with signs of hierarchical neuronal organization (Badre and D'Esposito, 2009), but the details of how this  organization implements selection and control of actions are far from settled. It has been argued that rather than assuming an exact correspondence between neuronal hierarchies and task hierarchies, higher neuronal hierarchical levels could in general encode task goal representations that are to be sustained over longer time scales (Uithol et al., 2012). Indeed, the idea of PFC being involved in sustaining neuronal activation over time has a long tradition, and also here both perception and action selection fit nicely within the same general framework, of PFC coming into play when something has to be kept active which could not otherwise sustain itself. Typical examples include working memory, for planned motor actions or perceptual representations to be maintained without any bottom-up sensory input (Fuster, 2000; Curtis and D'Esposito, 2003), as well as non-routine mappings between stimulus and response (Miller and Cohen, 2001; Deco and Rolls, 2005), see Figure ?Figure1C.1C. One hypothesis is that the to-be-sustained information or sensorimotor pathways themselves reside in more posterior brain networks, but that they need excitation from PFC to achieve sustained activity (Miller and Cohen, 2001; Curtis and D'Esposito, 2003; Postle, 2006).