Gray (1975; Hebb, 1949; McNaughton, 2004) suggested that in order to relate brain and behavior, one should first develop a “conceptual nervous system” to handle behavioral data, and second find out whether brain structures and neural elements carry out the operations described by the conceptual system. The present chapter shows that variables representing “neural activity” in the SLG model (see Chapter 2) are consistent to brain responses reported by Dunsmoor et al. (2007) during a human fear conditioning task. In the Dunsmoor et al. (2007) neuroimaging study, different patterns of neural activity were revealed to CSs that predicted an aversive US on all trials, half the trials or no trials. Computer simulations with the SLG model demonstrate that (a) activity in the amygdala and anterior cingulate is well characterized by the prediction of the US by the CS and the CX, BUS, (b) activity in the dorsolateral prefrontal cortex (dlPFC) and anterior insula is well described by the representation of the CS, XCS, and (c) the skin conductance response (SCR) is a nonlinear function of BUS. It is important to notice that variables BUS and XCS represent “neural activities” (see Figure 2.2), and not the strength of their related synaptic associations, VCS–US and zCS, which cannot be appreciated by functional magnetic resonance imaging (fMRI) methods.