Journal of Neurophysiology, Vol 65, Issue 1 76-86, Copyright © 1991 by APS

ARTICLES

Gustatory neural coding in the monkey cortex: stimulus intensity

T. R. Scott, C. R. Plata-Salaman, V. L. Smith and B. K. Giza
Department of Psychology, University of Delaware, Newark 19716.

1. We analyzed the activity of single neurons in gustatory cortex of alert cynomolgus monkeys in response to a range of stimulus intensities. Chemicals were deionized water, fruit juice, and several concentrations of the four prototypical taste stimuli: 10(-3)-1.0 M glucose, 10(-3)-1.0 M NaCl, 10(-4)-3 x 10(-2) M HCl, and 10(-5)-3 x 10(-3) M quinine HCl. 2. Taste-evoked responses could be recorded from a cortical gustatory area that measured 2.5 mm in its anteroposterior extent, 6.0 mm dorsoventrally, and 3.0 mm mediolaterally. Taste-responsive cells constituted 62 (3.7%) of the 1,661 neurons tested. Nongustatory cells gave responses associated with mouth movement (10.1%), somatosensory stimulation (2.2%), and approach or anticipation (0.9%). 3. Intensity-response functions were determined across 62 gustatory neurons. Neural thresholds for each stimulus quality conformed well to human psychophysical thresholds. Mean discharge rate was a direct function of stimulus concentration for glucose, NaCl, and quinine HCl. The most effective of the basic stimuli was glucose. 4. Power function exponents were calculated from the responses of neural subgroups most responsive to each basic stimulus. Those for glucose, NaCl, and quinine were within the range of psychophysically derived values. Thus the perceived intensity of each basic quality is presumably based on the activity of the appropriate neural subgroup rather than on the mean activity of all taste cells. 5. The mean breadth-of-tuning (entropy) coefficient for 62 gustatory neurons was 0.65 (range, 0.00-0.98). 6. There was no clear evidence of chemotopic organization in the gustatory cortex. 7. An analysis of taste quality indicated that sweet stimuli evoked patterns of activity that were clearly distinct from those of the nonsweet chemicals. Among the latter group, NaCl was differentiable from HCl and quinine HCl, whose patterns were closely related. 8. The response characteristics of cortical taste cells imply gustatory thresholds and intensity-response functions for the nonhuman primate that conform well to those reported in psychophysical studies of humans, reinforcing the value of this neural model for human taste intensity perception.

This article has been cited by other articles:

				R. Accolla, B. Bathellier, C. C. H. Petersen, and A. Carleton Differential Spatial Representation of Taste Modalities in the Rat Gustatory Cortex J. Neurosci., February 7, 2007; 27(6): 1396 - 1404. [Abstract] [Full Text] [PDF]

				J. R. Stapleton, M. L. Lavine, R. L. Wolpert, M. A. L. Nicolelis, and S. A. Simon Rapid Taste Responses in the Gustatory Cortex during Licking J. Neurosci., April 12, 2006; 26(15): 4126 - 4138. [Abstract] [Full Text] [PDF]

				R. Gutierrez, J. M. Carmena, M. A. L. Nicolelis, and S. A. Simon Orbitofrontal Ensemble Activity Monitors Licking and Distinguishes Among Natural Rewards J Neurophysiol, January 1, 2006; 95(1): 119 - 133. [Abstract] [Full Text] [PDF]

				T. C. Pritchard, E. M. Edwards, C. A. Smith, K. G. Hilgert, A. M. Gavlick, T. D. Maryniak, G. J. Schwartz, and T. R. Scott Gustatory Neural Responses in the Medial Orbitofrontal Cortex of the Old World Monkey J. Neurosci., June 29, 2005; 25(26): 6047 - 6056. [Abstract] [Full Text] [PDF]

				M. Kadohisa, E. T. Rolls, and J. V. Verhagen Neuronal Representations of Stimuli in the Mouth: The Primate Insular Taste Cortex, Orbitofrontal Cortex and Amygdala Chem Senses, June 1, 2005; 30(5): 401 - 419. [Abstract] [Full Text] [PDF]

				H. Ogawa, H. Ifuku, T. Nakamura, and S. Hirata Possible Changes in Information from the Primary to Higher-order Gustatory Cortices, Studied by Recording Neural Activities during a Taste Discrimination GO/NOGO Task in Monkeys Chem Senses, January 1, 2005; 30(suppl_1): i78 - i79. [Full Text] [PDF]

				J. V. Verhagen, M. Kadohisa, and E. T. Rolls Primate Insular/Opercular Taste Cortex: Neuronal Representations of the Viscosity, Fat Texture, Grittiness, Temperature, and Taste of Foods J Neurophysiol, September 1, 2004; 92(3): 1685 - 1699. [Abstract] [Full Text] [PDF]

				E. T. Rolls, J. V. Verhagen, and M. Kadohisa Representations of the Texture of Food in the Primate Orbitofrontal Cortex: Neurons Responding to Viscosity, Grittiness, and Capsaicin J Neurophysiol, December 1, 2003; 90(6): 3711 - 3724. [Abstract] [Full Text] [PDF]

				B. A. Arnow, J. E. Desmond, L. L. Banner, G. H. Glover, A. Solomon, M. L. Polan, T. F. Lue, and S. W. Atlas Brain activation and sexual arousal in healthy, heterosexual males Brain, May 1, 2002; 125(5): 1014 - 1023. [Abstract] [Full Text] [PDF]

				M. A. Barry, J. C. Gatenby, J. D. Zeiger, and J. C. Gore Hemispheric Dominance of Cortical Activity Evoked by Focal Electrogustatory Stimuli Chem Senses, June 1, 2001; 26(5): 471 - 482. [Abstract] [Full Text] [PDF]

				B. Cerf-Ducastel, P.-F. Van de Moortele, P. MacLeod, D. Le Bihan, and A. Faurion Interaction of Gustatory and Lingual Somatosensory Perceptions at the Cortical Level in the Human: a Functional Magnetic Resonance Imaging Study Chem Senses, May 1, 2001; 26(4): 371 - 383. [Abstract] [Full Text] [PDF]

				T. R. Scott, B. K. Giza, and J. Yan Gustatory Neural Coding in the Cortex of the Alert Cynomolgus Macaque: The Quality of Bitterness J Neurophysiol, January 1, 1999; 81(1): 60 - 71. [Abstract] [Full Text] [PDF]

				T. R. SCOTT, B. K. Giza, and J. Yan Electrophysiological Responses to Bitter Stimuli in Primate Cortex Ann. N.Y. Acad. Sci., November 30, 1998; 855(1): 498 - 501. [Abstract] [Full Text] [PDF]

				G. Hellekant, V. Danilova, and Y. Ninomiya Primate Sense of Taste: Behavioral and Single Chorda Tympani and Glossopharyngeal Nerve Fiber Recordings in the Rhesus Monkey, Macaca mulatta J Neurophysiol, February 1, 1997; 77(2): 978 - 993. [Abstract] [Full Text] [PDF]