The gustatory neocortex of the rat

Braun, J. Jay; Lasiter, Phillip S.; Kiefer, Stephen W.

doi:10.3758/bf03327004

Cited by 161 publications

(122 citation statements)

References 176 publications

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“…In fact, widespread damage to areas consistent with this location have been reported in studies using ablation, electrolytic, and even neurotoxic approaches in studies indicating a role for GC in CTA (e.g., refs. 2,18,21,22,25,27,30,36,37). This, coupled with the fact that previous studies (24,38) showed that neither damage to AI just caudal to GC nor to an area even more posterior in insular cortex than the hot spot identified here affected CTA, highlights the strong possibility that discrepancies across studies critically hinge upon the involvement of a specific area (or areas) of this cortical region.…”

Section: Discussionsupporting

confidence: 55%

High-resolution lesion-mapping strategy links a hot spot in rat insular cortex with impaired expression of taste aversion learning

Schier

Hashimoto

Bales

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Gustatory cortex (GC), an assemblage of taste-responsive neurons in insular cortex, is widely regarded as integral to conditioned taste aversion (CTA) retention, a link that has been primarily established using lesion approaches in rats. In contrast to this prevailing view, we found that even the most complete bilateral damage to GC produced by ibotenic acid was insufficient to disrupt postsurgical expression of a presurgical CTA; nor were such lesions sufficient to disrupt postsurgical acquisition and initial expression of a second CTA. However, some rats with lesions were significantly impaired on these tests. Further examination of all conditioned rats with lesions, regardless of the lesion topography, revealed a significant positive association between damage in the posterior portion of GC and especially within adjacent posterior regions of insular cortex. Accordingly, we developed a high-resolution lesion-mapping program that permitted the overlay of the individual lesion maps from rats with CTA impairments to produce a groupwise aggregate lesion map. Comparison of this map with one derived from the unimpaired counterparts indicated a specific lesion "hot spot" associated with CTA deficits that included the most posterior end of GC and overlying granular layer and encompassed an area provisionally referred to in the literature as visceral cortex. Thus, the detailed mapping of the lesion in behaviorally defined subgroups of rats allowed us to exploit the variability in performance to uncloak an important potential component of the functional topography of insular cortex; such an approach could have general applicability to other brain structure-function endeavors as well. W ith its primary receptors situated at the front end of the alimentary tract, the gustatory system is integrally involved in guiding food selection, promoting and discouraging intake, and evoking preparatory physiological reflexes (1). To best serve these functions, taste signals must confer with both the contemporary physiological milieu (e.g., satiety, malaise) and neurally stored representations of the associated effects of that particular taste stimulus [e.g., associative history with visceral malaise, as in conditioned taste aversion (CTA)]. However, the neural circuits underlying these critical integrative processes remain to be fully elucidated. In this regard, gustatory cortex (GC), an assemblage of taste-responsive neurons in the anterior dysgranular and agranular layers of insular cortex, is of particular interest (2-7). Receiving convergent input from both the thalamic and limbic taste pathways, GC consists of neurons that may potentially respond to various features of the taste stimulus, including chemosensory and hedonic alike, situated in close proximity to one another (5,(8)(9)(10)(11)(12)(13). Additionally, viscerosensory signals are received in the adjoining region of granular insular cortex (GI) just dorsal and posterior to GC (5,6,11,14). Extensive and reciprocating projections are found both within the subdivisions of G...

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Section: Discussionsupporting

confidence: 55%

High-resolution lesion-mapping strategy links a hot spot in rat insular cortex with impaired expression of taste aversion learning

Schier

Hashimoto

Bales

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…Similarly, because rats in group Devalue would respond to sweet with aversive responses, by associatively activating a perception of sweetness, the tone would provoke aversive responses in that group. Notably, although GC is not critical to basic functions of taste detection (e.g., Dunn and Everitt 1988), it has been shown to be importantly involved in many aspects of higher-level processing of taste memories (e.g., Braun et al 1982;Rosenblum et al 1995Rosenblum et al , 1997. Most relevant to the present study, Kiefer and Orr (1992) found that rats with GC lesions failed to replace appetitive taste-reactivity responses to a sweet flavor with aversive responses after flavor-illness pairings, even under circumstances under which those lesioned rats successfully learned to suppress overall consumption of that flavor.…”

Section: Discussionmentioning

confidence: 99%

Control of appetitive and aversive taste-reactivity responses by an auditory conditioned stimulus in a devaluation task: A FOS and behavioral analysis

Kerfoot¹,

Agarwal

Lee

et al. 2007

Learn. Mem.

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Through associative learning, cues for biologically significant reinforcers such as food may gain access to mental representations of those reinforcers. Here, we used devaluation procedures, behavioral assessment of hedonic taste-reactivity responses, and measurement of immediate-early gene (IEG) expression to show that a cue for food engages behavior and brain activity related to sensory and hedonic processing of that food. Rats first received a tone paired with intraoral infusion of sucrose. Then, in the absence of the tone, the value of sucrose was reduced (Devalue group) by pairing sucrose with lithium chloride (LiCl), or maintained (Maintain group) by presenting sucrose and LiCl unpaired. Finally, taste-reactivity responses to the tone were assessed in the absence of sucrose. Devalue rats showed high levels of aversive responses and minimal appetitive responses, whereas Maintain rats exhibited substantial appetitive responding but little aversive responding. Control rats that had not received tone-sucrose pairings did not display either class of behaviors. Devalue rats showed greater FOS expression than Maintain rats in several brain regions implicated in devaluation task performance and the display of aversive responses, including the basolateral amygdala, orbitofrontal cortex, gustatory cortex (GC), and the posterior accumbens shell (ACBs), whereas the opposite pattern was found in the anterior ACBs. Both Devalue and Maintain rats showed greater FOS expression than control rats in amygdala central nucleus, GC, and both subregions of ACBs. Thus, through associative learning, auditory cues for food gained access to neural processing in several brain regions importantly involved in the processing of taste memory information.Reinforcer devaluation procedures are often used to assess cues' ability to guide behavior based on their access to a representation of the current incentive value of the reinforcer. For example, after tone-food pairings, the establishment of an aversion to the food reinforcer results in the spontaneous reduction of rats' learned food-cup approach responses to the tone, when it is presented later in the absence of food (Holland and Straub 1979). Thus, the rats' response to the tone is sensitive to changes in reinforcer value, despite no explicit experience of the tone together with the devalued reinforcer. Recent studies (for review, see Holland and Gallagher 2004) showed that this sensitivity of previously learned behaviors to subsequent alterations in reinforcer value demands function of a brain system that includes the basolateral amygdala (BLA) and the lateral orbitofrontal cortex (OFC).Previous devaluation studies examined changes in performance of learned responses preparatory to the receipt of food, such as food-cup approach. Here, we considered whether a learned cue for food would provoke consummatory responses that reflect the current sensory-hedonic aspects of food. In the absence of food itself, would a food cue provoke "liking" or "disgust" responses appropriate to the current...

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“…Although this could readily explain a lesion-induced overconsumption of saccharin on the first pre-exposure trial (lower concentrations of saccharin evoke less neophobia than do higher concentrations), it would not mean that ICX-Novel rats would acquire the taste aversion as slowly as the ICX-Familiar subjects [latent inhibition occurs even with low concentrations of saccharin; for example, De La Casa & Lubow (2002) used 0.04% saccharin]. Finally, it might be noted that there is empirical evidence that IC lesions do not disrupt basic taste perception (Braun et al 1982).…”

Section: Discussionmentioning

confidence: 99%

Effects of insular cortex lesions on conditioned taste aversion and latent inhibition in the rat

Roman

Reilly

2007

Eur J of Neuroscience

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The present study tested the hypothesis that lesions of the insular cortex of the rat retard the acquisition of conditioned taste aversions (CTAs) because of an impairment in the detection of the novelty of taste stimuli. Demonstrating the expected latent inhibition effect, nonlesioned control subjects acquired CTAs more rapidly when the conditioned stimulus (0.15% sodium saccharin) was novel rather than familiar (achieved by pre-exposure to the to-be-conditioned taste cue). However, rats with insular cortex lesions acquired taste aversions at the same slow rate regardless of whether the saccharin was novel or familiar. The pattern of behavioural deficits obtained cannot be interpreted as disruptions of taste detection or stimulus intensity, but is consistent with the view that insular cortex lesions disrupt taste neophobia, a dysfunction that consequently retards CTA acquisition because of a latent inhibition-like effect.

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The gustatory neocortex of the rat

Cited by 161 publications

References 176 publications

High-resolution lesion-mapping strategy links a hot spot in rat insular cortex with impaired expression of taste aversion learning

High-resolution lesion-mapping strategy links a hot spot in rat insular cortex with impaired expression of taste aversion learning

Control of appetitive and aversive taste-reactivity responses by an auditory conditioned stimulus in a devaluation task: A FOS and behavioral analysis

Effects of insular cortex lesions on conditioned taste aversion and latent inhibition in the rat

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