Figure 2.

An orbitofrontal cortex (secondary taste cortex) neuron with responses nonlinearly correlated with decreases in the CSF (a). The neuron responds almost not at all until the CSF falls below 0.04. The neuron is thus very selective for fat texture, because of its nonlinear response in relation to the CSF. The linear regression line has a correlation of r = −0.68 (P = 0.02). (b): There is a much weaker relation to viscosity (r = 0.08, P = 0.82), with the oils producing a larger response than predicted linearly. Further, a regression line through the nonoil stimuli would have a lower slope. Conventions as in Fig. 1. Si280: silicone oil with a nominal viscosity of 280 cP.