To characterize electrophysiological and receptive field properties, we recorded extracellular responses from single GG neurons to lingual application with chemical, thermal and mechanical stimuli.  Based on responses to these stimuli, GG neurons were divided into CHEMICAL, CHEMICAL/THERMAL, THERMAL and TACTILE groups.  CHEMICAL/THERMAL neurons responded to both taste stimuli and cold water.  THERMAL neurons responded only to cold water and TACTILE neurons responded only to light stroking stimuli.  The receptive field sizes for CHEMICAL, and CHEMICAL/THERMAL neurons averaged five papillae exceeding the field size of THERMAL and TACTILE neurons which averaged about two papillae.  Detailed analysis of the receptive field of CHEMICAL/THERMAL neurons revealed that within one field only a subset of the fungiform papillae making up the receptive field responded to the cold stimuli, whereas the other papillae responded only to chemical stimuli. 
THERM