Multisensory interactions underlying flavor consumption in rats: the role of experience and unisensory component liking

Abstract

The mechanisms by which taste and odor are combined in determining food choice behavior are poorly understood. Previous work in human subjects has yielded mixed results, potentially due to differences in task context across studies, and a lack of control over flavor experience. Here, we used rats as a model system to systematically investigate the role of experience and unisensory component liking in the multisensory interactions underlying consumption behavior. We demonstrate that taste–smell mixture consumption is best explained by a linear average of component liking. The observed pattern of results was not dependent on prior experience with specific taste–smell combinations, and unique for multisensory as opposed to unisensory mixture consumption. The results are discussed with respect to existing models of flavor integration, and a maximum-likelihood integration model previously described for multisensory judgments in other systems.

Adaptive weighting of taste and odor cues during flavor choice

“…The multisensory computation observed in the present study is consistent with the flexible nature of multisensory flavor correspondences in that it did not appear to depend on experience with specific taste-odor combinations (animals had no prior experience with the particular mixtures used during testing). This is consistent with two recent studies investigating tasteodor mixture consumption (Elliott and Maier 2020;McQueen et al 2020) and may reflect the imperative to evaluate any flavor stimulus upon consumption (regardless of experience with that particular taste-odor combination). However, previous psychophysical studies measuring perception of objective flavor properties (identity judgments, detection) consistently show that responses to taste-odor mixtures yield responses that are enhanced relative to the unisensory components (Dalton et al 2000;Seo et al 2013;Shepard et al 2015;Veldhuizen et al 2010b;Welge-L€ ussen et al 2009;White and Prescott 2007) in a manner that cannot simply be explained by summation of independent unisensory processing channels (Veldhuizen et al 2010b).…”

Multisensory integration of orally‐sourced gustatory and olfactory inputs to the posterior piriform cortex in awake rats

“…‘sweetness’ of vanilla). The apparent lack of palatability‐related taste input to pPC further suggests that multisensory interactions related to hedonic judgments of taste + odour mixtures (Elliott & Maier, 2020; Maier & Elliott, 2020) occur elsewhere. For example, gustatory cortex has been shown to encode hedonic aspects of taste stimuli (Katz et al., 2001; Maier & Katz, 2013; Moran & Katz, 2014; Sadacca et al., 2012) and may contain amodal representations of palatability (Samuelsen & Fontanini, 2017).…”

“…Instead, our data show that taste responses are taste‐specific and not primarily related to palatability. Regarding mixtures, taste palatability affects mixture palatability in a predictable manner, such that the addition of a palatable/unpalatable taste results in an overall increase/decrease in mixture palatability relative to odour palatability (Elliott & Maier, 2020; Maier & Elliott, 2020). Thus, if pPC activity patterns were the result of orofacial movements, mixtures that feature tastes of similar palatability would yield similar interaction patterns.…”

Taste-Odor Association Learning Alters the Dynamics of Intraoral Odor Responses in the Posterior Piriform Cortex of Awake Rats

“…During consumption, odor stimuli are typically experienced in mixture with taste. Behavioral work has shown that interactions between taste and odor components of flavor are highly adaptive in informing consumption decisions ( Holman, 1975 ; Sclafani and Ackroff, 1994 ; Slotnick et al, 1997 ; Blankenship et al, 2019 ; Elliott and Maier, 2020 ; Maier and Elliott, 2020 ). One example of taste-odor interactions during consumption is the formation of taste-odor associations.…”