Even worse, it turned out that motor maps derived from the same species

by different investigators could differ considerably. It was also observed that motor maps are not even entirely consistent Selleckchem Fulvestrant within experiments, an observation referred to “functional instability of cortical motor points” by Sherrington. Finally, it was found that musclelotopy captures the complexity of cortical motor organization only partially (Schieber, 2001) and that motor cortex might contain multiple entirely different maps. In particular, when long and intense stimulation trains are used, one can evoke from single motor cortical sites complex, “goal-directed” motor behaviors (Graziano et al., 2002). As these movements include sequences of very different muscle activation patterns, they require some kind of remapping of motor output during behavior. Behaviors map in an orderly fashion onto motor cortex and are organized according to “ethological” categories, i.e., defensive behaviors, reaching behaviors, etc. Ultimately, investigators started to integrate cytoarchitectonic, connectional, recording, and lesion data in their concepts of cortical localization, but—while it greatly expanded our knowledge of cortical circuitry—it also led to novel disagreements and an even wider variety PI3K Inhibitor Library of cortical partitioning schemes. This has led to a Babylonian confusion about

how to label cortical areas. Thus, two studies published in this issue of Neuron report data from exactly the same area in rodent cortex, but they refer to it under different names, namely as vibrissae primary motor cortex (vM1; Hill et al., 2011) or frontal orienting field (FOF; Erlich et al., 2011). If there were just two names for this area, we would probably deal with it, but the reality is that this exact same piece of cortex has also been referred to as anteromedial cortex, dorsomedial prefrontal cortex, medial precentral cortex, frontal eye field (FEF), vMC (vibrissa motor

cortex), agranular medial area (AgM), frontal area 2 (F2), and secondary motor cortex (M2). This cacophony of names fundamentally impairs our ability to communicate our findings. There is hope, however. First, investigators have taken up the challenge posed by cortical complexity. Specifically nearly as reported in this issue, Hill et al. (2011) and Erlich et al. (2011) performed sophisticated recording, blocking, and deafferentation experiments in rats. Perhaps most importantly, the researchers overcame the temptation to be original and performed experiments very similar to those that had been done before in other cortical areas and species. As discussed in depth below, the results reveal both intriguing similarities and crystal-clear differences between cortical areas; collectively, the experiments make one feel that we are on the road of clarification about motor cortices.