Biology subjects

Luckett, C. R.

Publications and source records attributed to Luckett, C. R..

3 recordsLinked to original sources

bioRxiv2018

The Effect of Oral Tactile Sensitivity on Texture Perception and Mastication Behavior in Humans

Mastication behavior is a notable source of interindividual variation in texture perception and could be linked to oral sensitivity. As oral sensitivity declines so does the amount of tactile feedback relayed to the brain, resulting in less effective manipulation or food and a reduced ability to discriminate differences. To address these hypotheses, we measured masticatory behavior and related this to texture discrimination and oral sensitivity. The study was performed on 41 participants in two groups, with high (n = 20) or low (n=21) sensitivity. Oral sensitivity was measured using a battery of tests that included: oral stereognosis, lingual tactile acuity, and bite force sensitivity. Sensitivity to texture changes was measured using a series of triangle tests with confectionaries of different hardness, with masticatory patterns and behaviors being video recorded and analyzed using jaw tracking software. Overall, there was no significant difference between high and low sensitivity participants and their ability to distinguish texture changes. But, there were significantly different trends found between the groups based on their masticatory behaviors including chewing pattern and overall number of chews. But, it was found that multiple masticatory behaviors were being modulated by oral sensitivity, including overall chewing cycles used (p < 0.0001). More, specifically those in the high sensitivity group used more stochastic chewing movements, while those in the low sensitivity group were found to use crescent-shaped chewing cycles. It was also noted that in the high sensitivity group the jaw moved further distances (p < 0.0001) in all phases and moved at a higher velocity when opening (p < 0.0001) but not when closing, when compared to the low sensitivity group. These results help bolster evidence that mastication and oral sensitivity are related.

physiology↗

bioRxiv2018

Characterization of Oral Tactile Sensitivity and Chewing Efficiency Across Adulthood

Texture perception is one of the most important factors in food acceptance, yet population-wide differences in texture sensations are not well understood. The variation in texture perception across populations is thought to depend on oral tactile sensitivity and oral processing behaviors. To address this hypothesis, we aimed to measure tactile acuity with a battery of tests and quantitate the relationship to oral processing. The study was performed on 98 participants, in 3 age groups (20-25, 35-45, or over 62). Two main measures of oral sensitivity were performed: to assess bite force, subjects were asked to discriminate between foam samples of varying hardness. Secondly, to assess lingual sensitivity the subjects were asked to identify 3D printed shapes, ranging from 3mm to 8mm, using their tongue, as well as identify confectionary letters. Additionally, chewing efficiency was measured through assessing each participants ability to mix two-colored chewing gum. In general, we found that sensitivity and chewing efficiency in the younger age groups was superior to that of older adults (p<0.0001). We also found a positive linear trend between bite force sensitivity and chewing efficiency with younger participants, a trend not found in older participants. We found no significant relationship between age groups for bite force and chewing efficiency, suggesting that age-related declines in bite force sensitivity are not a significant cause of altered oral processing ability. These results help bolster evidence that sensitivity and oral processing are related, as well previously reported declines in both as people age.

physiology↗

bioRxiv2018

Retronasal Habituation: Characterization and Impact on Flavor Perception using Time-Intensity

Olfactory habituation results from prolonged exposure to an odor, leading to perceptual changes defined by several characteristics. To date, human habituation research has focused on orthonasal olfaction which is perceived externally while ignoring internal routes of odor perception related to flavor. In our study, we conducted two experiments to characterize retronasal olfactory habituation and measured its impact on flavor perception. In Experiment 1, 22 participants rhythmically breathed a food odor (lime), non-food odor (lavender), and blank (propylene glycol) that was presented using an orally-adhered strip, while rating the odor intensity using the time-intensity procedure. After a 10-minute exposure, the participants ate a lime-flavored gummy and rated the lime flavor. In Experiment 2, the same procedure was performed for a low-level lime odor, a simple (lime oil) and complex (lime oil + sucrose + citric acid) beverage as the flavor stimuli. Our results demonstrated two known principles of habituation for retronasally presented odors: 1) prolonged exposure lead to decreased perception, 2) weaker stimuli lead to more rapid habituation. Additionally, we found that the non-food odor habituated slower than the food odor; however, the participants seemed to recover simultaneously upon food and beverage consumption leading to no change in flavor perception.

neuroscience↗