Figure 4.

A neuron in the primate orbitofrontal cortex responding to the texture of fat in the mouth independently of viscosity. The cell (bk265) increased its firing rate to a range of fats and oils (the viscosity of which is shown in cP). The information that reaches this type of neuron is independent of a viscosity sensing channel, in that the neuron did not respond to the methyl cellulose (CMC) viscosity series. The neuron responded to the texture rather than the chemical structure of the fat in that it also responded to silicone oil (Si(CH₃)₂O)_n) and paraffin (mineral) oil (hydrocarbon). Some of these neurons have taste inputs (After Verhagen et al. 2003).