discern an earlier negativity that arises in association with a sink/source configuration and a brief MUA burst below layer 4 (“-1” in Fig. 1 C). Modeling and physiology experiments suggest that the initial transient responses in primary sensory cortices are a combination of presynaptic (afferent terminal discharge), and postsynaptic (granule cell depolarization) processes (Schroeder et al., 1995;Steinschneider et al., 1992;Tenke et al., 1993). In most cases the presynaptic component is masked by a much larger postsynaptic component.
