In all cases, the electrode and cannula placements in FOF were within the borders of M2 and between 2 and 3 mm anterior to Bregma (Paxinos and Watson, 2004). In all cases the M1 placements were within the borders of M1 and between 2.5 and 3.5 mm anterior to Bregma (Paxinos and Watson, 2004).

We thank B.W. Brunton and J.K. Jun for contributions to software to obtain head direction data, D.W. Tank and J.P. Rickgauer for suggestions to improve whisker tracking, B.W. Brunton, J.K. Jun, check details C.D. Kopec, and T. Hanks for discussion and comments on the manuscript, A. Keller and D. Kleinfeld for discussions related to the role of the FOF in whisker control, and L. Osorio and G. Brown for technical assistance. This work was supported by the Howard Hughes Medical Institute. “
“The purposeful movement of biological sensors, such as the motion of the eyes (Leigh et al., 1997) or hands (Shadmehr and Wise, 2005), is an essential part of perception. What algorithms incorporate movement as part of perception at the level of cortex? In particular, over what timescales does motor cortex direct the motor plant associated with a sensory modality? Motor cortex may be hypothesized to

maintain different pathways for fast and slow control Palbociclib mw of the motor plant. This is particularly relevant for the large repertoire of repetitive behaviors, such as those involved with scanning sensory systems involved with touch, vision, and even olfaction (Diamond et al., 2008 and Nelson and MacIver, 2006), in which fast rhythmic motion is modulated by a slowly varying amplitude and/or change in orientation. To test this hypothesis, we address how trains of spikes from single units in primary motor (vM1) cortex represent the motion of the vibrissae during free whisking in rat. The rodent vibrissa system is a scanning

sensorimotor system in which the sensors, i.e., long hairs referred to as vibrissae, rapidly scan a region around the head of the animal (Carvell and Simons, 1990, Knutsen et al., 2006 and Mehta et al., 2007) with an angular extent that evolves only slowly in time (Carvell and Simons, 1990 and Guic-Robles et al., 1989). The primary sensory organ of the rat vibrissa system is the vibrissa-follicle complex. This is composed of Levetiracetam pressure-sensitive cells that respond to external stimulation as well as internal motor drive of a long hair that originates in the follicle (Szwed et al., 2006). The follicle is swept rhythmically back and forth by muscles in the mystacial pad to permit the hairs to touch and probe objects that are located close to the head of the animal (Kleinfeld et al., 2006). While the rat can exhibit a variety of whisking patterns (Berg and Kleinfeld, 2003a, Carvell and Simons, 1995, Mitchinson et al., 2007 and Towal and Hartmann, 2006), we focus on exploratory rhythmic whisking in the absence of exafferent stimuli.