Microstructural analysis of negative anticipatory contrast: A reconsideration of the devaluation account

Abstract

An animal's appetitive behavior is not a fixed response to current stimulation but can be affected by the anticipation of future events. For example, rats regularly given access to a moderately valued solution followed by a higher value solution (e.g., 4 % sucrose → 32 % sucrose) consume less of the initial solution than in control conditions where the initial solution is not followed by a higher value solution (e.g., 4 % sucrose → 4 % sucrose). Previous analyses have suggested that this negative anticipatory contrast effect does not depend on the "expectation" of a valuable stimulus producing a functional devaluation of a currently available stimulus of lesser value. In a withinsubjects anticipatory contrast procedure, this study revealed that both consumption and the mean size of licking clusters were smaller for a 4 % sucrose solution on days when it preceded 32 % sucrose than on days when 4 % preceded 4 %. Since lick cluster size typically bears a positive monotonic relationship with the concentration of palatable solutions, this reduction is indicative of a decrease in the palatability/hedonic value of the solution subject to contrast. As such, we provide direct evidence that negative anticipatory contrast does produce a functional devaluation of the solution, thus challenging prevailing theoretical assumptions.

Temporal averaging across multiple response options: insight into the mechanisms underlying integration

“…For example, in Wright et al (2013), rats were given access to either a 4% sucrose solution for two minutes followed by a 32% solution for another two minutes during some sessions or a 4% sucrose solution for four minutes during other sessions. Each session type was signaled by distinct contextual cues.…”

Wistar Kyoto Rats Display Anhedonia In Consumption but Retain Some Sensitivity to the Anticipation of Palatable Solutions

“…Following a 4-s intersolution interval, the second solution was then made available for 6 min on the right-hand side of the chamber. The apparatus and procedures are the same we have reported previously (Wright et al, 2013).…”

“…Lick cluster size (defined as the mean number of licks per cluster) was extracted from the MED-PC data. As in our lab's previous experiments using these general methods and equipment (e.g., Lydall et al, 2010;Dwyer et al, 2011Dwyer et al, , 2018Wright et al, 2013), a cluster was defined as series of licks, with each lick separated by no more than a 0.5 s interval. The same criterion had been adopted by Davis and his colleagues (e.g., Davis, 1989;Davis and Smith, 1992;Davis and Perez, 1993).…”

“…To address both anticipatory and consummatory aspects of anhedonia in WKY rats we used an anticipatory contrast procedure (e.g., Flaherty and Rowan, 1985;Flaherty, 1996). This involves giving rats access to two solutions each day when the first solution is of a lower concentration than the second (e.g., 4% then 32% sucrose), both consumption of, and the lick cluster size for, the initial solution is suppressed compared to when the two solutions are of equal concentration (Arthurs et al, 2012;Wright et al, 2013). Thus, anticipatory contrast involves the downregulation of the current hedonic experience based on the expectation of a future event of high value and reflects anticipatory aspects of hedonic responses.…”

Lickometry: A novel and sensitive method for assessing functional deficits in rats after stroke

“…For detailed methods, see supplemental information and literature. 26 , 27 Two weeks after lickometry, the total amount of rat chow consumed in 1 h was also assessed. Rats were perfused between 90 and 100 days, brain sections stained with NeuN (1:4000, Chemicon, UK).…”