Gustatory thalamus lesions eliminate successive negative contrast in rats: Evidence against a memory deficit.

Reilly, Steve; Trifunovic, Radmila

doi:10.1037/0735-7044.117.3.606

Cited by 18 publications

(18 citation statements)

References 33 publications

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“…Groups included in the behavioral analysis were: SHAM-Saline (n = 11), SHAM-Morphine (n = 10), GTX-Saline (n = 8), and GTX-Morphine (n = 8). GT Lesions in the current study were comparable in size and locus to those in our earlier work (e.g., [58,49,53,54]).…”

Section: Methodssupporting

confidence: 84%

Role of the gustatory thalamus in taste learning

Arthurs

Reilly

2013

Behavioural Brain Research

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The present study re-examined the involvement of the gustatory thalamus (GT) in the acquisition of drug- and toxin-induced conditioned taste aversions (CTAs) using a standardized procedure involving 15-min taste trials in rats injected with morphine (Experiment 1), lithium chloride (Experiment 2) or amphetamine (Experiment 3). Contrary to previous results, GT lesions did not eliminate drug-induced CTAs. Rather, GT-lesioned rats acquired aversions of comparable magnitude to non-lesioned subjects but from an elevated intake on the first conditioning trial. A similar pattern of lesion effects was found in the acquisition of an illness-induced CTA. Thus, we conclude that GT lesions do not differentially influence CTAs conditioned with drugs or toxins. The lesion-induced elevated intake of a novel tastant confirms an unappreciated role for the GT in taste neophobia.

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Section: Methodssupporting

confidence: 84%

Role of the gustatory thalamus in taste learning

Arthurs

Reilly

2013

Behavioural Brain Research

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“…In support of this, rats with lesions of the gustatory thalamus not only fail to demonstrate an ACE but also a successive negative contrast effect that occurs when intact rats are unexpectedly shifted from a greater to a lesser reward (40,42,43). In this case, intake of the lesser 0.15% saccharin reward is reduced in the lesioned rats when downshifted from a 1.0 M sucrose solution, but only to the level of the unshifted saccharin controls (42).…”

Section: Discussionmentioning

confidence: 56%

“…The successive negative contrast effect, on the other hand, is a multistage phenomenon that depends upon comparing an available level of reward (4% sucrose or 0.15% saccharin) with the memory of a preferred sucrose reward (32% or 1.0 M sucrose) that was received 24 h earlier. A simple short-term/long-term memory distinction, however, likely will not account for the dissociation in the lesion data, as Reilly and Trifunovic (43) showed that thalamic lesions disrupted successive negative contrast effects even when the downshift occurred only 7.5 min (rather than 24 h) after the final access period to the preferred 1.0 M sucrose reward, and simultaneous negative contrast effects, in turn, remain intact in THLX rats even when as much as 8 min elapsed between alternating access periods to the two disparate levels of reward within a given daily session (38).…”

Section: Discussionmentioning

confidence: 90%

“…As such, the lesion may disrupt anticipatory contrast and successive negative contrast because an intact gustatory thalamus is necessary to compare the value of an available reward with the long-term memory of an alternative reward. This interpretation would have to suggest that THLX rats failed to exhibit a successive negative contrast effect, even when downshifted 7.5 min after a final access period to the preferred 1.0 M sucrose reward (43), because contrast, in this case, depended upon comparison with the long-term memory of the preferred reward, not with the characteristics of the stimulus that was received 7.5 min earlier. Were the important comparison that between the available reward and the characteristics of the stimulus received 7.5 min earlier, then this would have been a simultaneous, rather than a successive, contrast paradigm and the contrast behavior of the THLX rats should not have been impaired (41).…”

Section: Discussionmentioning

confidence: 92%

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Role of gustatory thalamus in anticipation and comparison of rewards over time in rats

Schroy

Wheeler

Davidson

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

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Rats reduce intake of a palatable saccharin solution when it is followed by access to a preferred sucrose solution. This phenomenon, referred to as an anticipatory contrast effect (ACE), is thought to occur because the value of the saccharin conditioned stimulus pales in comparison to the highly rewarding sucrose unconditioned stimulus expected in the near future. Although relatively little is known about the underlying neural substrates, lesions of the gustatory thalamus fully disrupt the phenomenon (Reilly S, Bornovalova M, and Trifunovic R. Behav Neurosci 118: 365-376, 2004; Reilly S and Pritchard TC. Behav Neurosci 110: 746-759, 1996). The present set of experiments revisited this issue to determine the nature of this deficit. Rats with bilateral ibotenic acid lesions of the gustatory thalamus were given 3-min access to 0.15% saccharin and, after a 0-s or 5-min interval, were given 3-min access to either the same saccharin solution or a highly preferred 1.0 M sucrose solution. In experiment 1, ACE testing began with the 5-min interstimulus interval (ISI) and then switched to the 0-s ISI. For experiment 2, the order of ISI testing was reversed. The results show that axon-sparing, neurotoxic lesions of the gustatory thalamus prevent ACEs with a 0-s ISI and lead to a reversal (i.e., a reinforcement effect) with a 5-min ISI. Together, the results suggest that the lesion leads to a specific reward comparison deficit, whereby the rats fail to compare the value of an available reward with the memory of a preferred reward that is anticipated in the near future.

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“…The thalamic relay for tongue taste, thermal, and tactile sensibility, however, had little influence on the same three tasks when rewarded by either sucrose or corn oil. Somewhat more medial thalamic taste area lesions had no effect on preference tests, CTA, or Na-appetite [24, 27, 33], but did block ACE and successive negative contrast effect [24, 25, 35]. The results did not support our hypothesis that the TOA is necessary for oil reward, but indicated that the TOA might process sucrose and oil differently.…”

Section: Discussionmentioning

confidence: 63%

Pontine and thalamic influences on fluid rewards: III. Anticipatory contrast for sucrose and corn oil

Liang

Norgren

Grigson

2012

Physiology & Behavior

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An anticipatory contrast effect (ACE) occurs when, across daily trials, an animal comes to respond less than normally to a first stimulus when it is followed shortly by a second, more preferred solution. Classically, ACE is studied using a low (L) concentration of saccharin or sucrose, followed by access to a higher (H) concentration of sucrose. Subjects in the control condition have two bouts of access to the weaker solution presented on the same schedule. The ACE is measured by the difference in intake of the first bout low solution between subjects in the low-low (L-L) vs. the low-high (L-H) conditions. Here we used this paradigm with sham feeding rats and determined that nutritional feedback was unnecessary for the development of ACE with two concentrations of sucrose or with two concentrations of corn oil. Next we showed that ibotenic acid lesions centered in the orosensory thalamus spared ACEs for both sucrose and corn oil. In contrast, lesions of the pontine parabrachial nuclei (PBN), the second central relay for taste in the rat, disrupted ACEs for both sucrose and corn oil. Although the sensory modalities needed for the oral detection of fats remain controversial, it appears that the PBN is involved in processing the comparison of disparate concentrations of sucrose and oil reward.

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Gustatory thalamus lesions eliminate successive negative contrast in rats: Evidence against a memory deficit.

Cited by 18 publications

References 33 publications

Role of the gustatory thalamus in taste learning

Role of the gustatory thalamus in taste learning

Role of gustatory thalamus in anticipation and comparison of rewards over time in rats

Pontine and thalamic influences on fluid rewards: III. Anticipatory contrast for sucrose and corn oil

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