Responses of primate cortical neurons to unitary and binary taste stimuli

• DOI: 10.1152/jn.1996.75.1.396
• Publication Date: 2017-12-25T00:00:37Z
• Authors: Y. Miyaoka; T. C. Pritchard
• Keywords: Umami; Stimulus (psychology); Sweetness; Monosodium glutamate

1. The responses of 126 neurons in primary gustatory cortices two rhesus monkeys were recorded during sapid stimulation the tongue with 18 taste stimuli. Ten these stimuli dissolved distilled water (DW): 1.0 M sucrose (Suc), 0.1 and 0.03 sodium chloride (NaCl), 0.003 hydrochloric acid (HCl), 0.001 quinine hydrochloride (QHCl), monosodium glutamate (MSG), polycose, 0.3 glycine, proline, malic acid. Seven other MSG; last stimulus was a mixture Suc NaCl. 2. average spontaneous rate (2.2 +/- 0.2 spikes/s, mean SE) response to DW (2.5 0.2) low but within range previously reported for primate cortex. most effective 24.1% tested followed by NaCl (15.7%), QHCl (14.8%), HCl (11.1%), MSG (10.2%), miscellaneous unitary (8.3%). Binary mixtures 15.7% sample. net (corrected DW, spikes/s) Suc-best (3.3), NaCl-best (4.3), HCl-best (3.4), QHCl-best (2.3), MSG-best (4.1) sluggish, comparable that previously. 3. breadth 82 responded best either Suc, NaCl, HCl, or measured entropy coefficient indicated moderate (mean = 0.79; 0.30-0.98). According criteria adopted this experiment (water 1.96 SD), however, 81 (98.1%) only one four basic disparity between entropy- criterion-based measures derive from nature statistics. Adjustments would make statistic less inclusive definition according statistical exclusive increase their concordance. 4. Three multivariate statistics (cluster, principal axis factor, multidimensional analysis) used analyze data. Cluster analysis enabled us divide into groups on basis similarity. Each largest dominated stimuli: QHCl, (ranked descending order); fifth cluster contained MSG. Principal factor demonstrated 80.8% total variance could be accounted three factors. Neurons responding each closely associated those factors, loadings evenly distributed across all communality factors > 80% Suc-, NaCl-, HCl-, neurons; neurons, comparison, had very few high any correspondingly 40.4%, difference statistically significant groups. Thus related are not relevant neurons. We arrange five loosely arranged partially overlapping clusters. A space based similarity showed as different they another. 5. Mixture suppression, common observation human psychophysical experiments, examined at neurophysiological level including binary tastants battery. 19 (4.1 decreased near 0 when solvent changed Similar decrements observed NaCl- Suc/NaCl mixtures.