Gustatory Cortex - Tastant Concentration-dependent Neuronal Activity

Tastant Concentration-dependent Neuronal Activity

GC chemosensory neurons exhibit concentration dependent responses. In a study done on GC responses in rats during licking, an increase in MSG (Monosodium Glutamate) concentration lingual exposure results in an increase in firing rate in the rat GC neurons, whereas an increase in sucrose concentration resulted in a decrease in firing rate. GC neurons exhibit rapid and selective response to tastants. Sodium Chloride and Sucrose elicited the largest response in the rat gustatory cortex in rats, whereas citric acid causes only a moderate increase in activity in a single neuron. Chemosensory GC neurons are broadly tuned, meaning that a larger percentage of them respond to larger amount of tastants (4 and 5) as compared to the lower percentage responding to a fewer amount of tastants (1 and 2). In addition the number of neurons responding to a certain tastant stimuli varies. In the rat gustatory complex study it was shown that more neurons responded to MSG, NaCl, sucrose, and citric acid (all activating approximately the same percentage of neurons) as compared to the compounds quinine (QHCl) and water.