== Data were collected during penetrations of the hand representation in area 3b with 0.34 mm diameter linear array multicontact electrodes (24 contacts; 0.10.3 M impedence; Neurotrak) that record from all cortical layers simultaneously (Fig. to a single digit is represented. == Introduction == Studies of the primate hand representation in primary somatosensory cortical area 3b have consistently identified separate representations of each digit (Powell MP470 (MP-470, Amuvatinib) and Mountcastle, 1959b;Jones and Powell, 1969;Paul et al., 1972;Sur et al., 1982;Pons et al., 1987;Kaas, 1993). This detailed surface representation is a cornerstone of hierarchical organization in the somatosensory system, providing a substrate for specific computational functions of higher order cortices (Burton and Sinclair, 1996;Moore et al., 1999). The capacity for radical spatial reorganization in the area 3b digit map shows clearly that it is not invariant (Allard et al., 1991;Rasmusson et al., 1992;Mogilner et al., 1993;Zarzecki et al., 1993;Schroeder et al., 1997). The rapidity and preferred pattern of heterotopic functional reorganization in area 3b (Allard et al., 1991;Zarzecki et al., 1993) suggests changes in the gain of existing heterotopic neuronal connections underpin these effects (Jenkins and Merzenich, 1987;Turnbull and Rasmusson, 1990;Clarey et al., 1996;Coq and Xerri, 1999). The existence of heterotopic connections in the normal intact digit map can be inferred from numerous previous observations in monkeys. For example, (1) the axon terminals of single thalamocortical neurons span regions of area 3b cortex several times the diameter of an individual digit representation (Garraghty and Sur, 1990), (2) stimulation of digits outside of the driving input of a single area 3b neuron elicits subthreshold postsynaptic potentials (Zarzecki et al., 1993), (3) ambient activity in the median nerve territory of area 3b is strongly modulated by stimulation of radial nerve afferents (Schroeder et al., 1995a), (4) the spatial pattern of hemodynamic response in area 3b to single digit stimulation is changed by adjacent digit stimulation (Chen et al., 2003;Friedman et al., 2008), and perhaps most importantly (5) a recent study in anesthetized New World monkeys (Reed et al., 2008) showed that neurons at least 2 mm apart in the area 3b hand map could synchronize stimulus-evoked firing. Neuronal recordings in rodent barrel cortex (Nicolelis et al., 1998;Moore et al., 1999;Andermann and Moore, 2006), raccoon hand (Greek et al., 2003), and monkey forearm (Gardner and Costanzo, 1980), as well as magnetoencephalographic studies of the human hand MP470 (MP-470, Amuvatinib) representation (Buchner et al., 1999;Noppeney et al., 1999;Braun et al., 2000,2002;Iguchi et al., 2001;Jones et al., 2007) indicate that area 3b neurons integrate far more stimulus and state of the system information than initially suspected. Collectively, the above findings suggest that expression of the digit map in primate area 3b is dynamic and context dependent. We systematically tested functional interactions between digit representations to define the dimensions over which such heterotopic interactions occur in awake macaques. Our findings show that activity within a digit representation is modulated by stimulation of any of the other digits, and that interactions can extend across the entire digit map. Importantly, we demonstrate that these effects occur in real time in awake intact animals. Control experiments rule out effects attributable to attention and mechanical spread of stimulation. We thus confirm that, MP470 (MP-470, Amuvatinib) even at the first stage of somatosensory DcR2 cortical processing, inputs from potentially all of the digits frame the context within which the input to a single digit is represented. == Materials and Methods == Intracortical multielectrode recordings were performed in two female rhesus macaques (Macaca mulatta). All animal experimentation was reviewed, approved, and monitored by the local Institutional Animal Care and Use Committee and complied with United States Public Health Service guidelines for.