Activity in the Hypothalamus, Amygdala, and Cortex Generates Bilateral and Convergent Modulation of Pontine Gustatory Neurons

Lundy, Robert F.; Norgren, Ralph

doi:10.1152/jn.00840.2003

Cited by 101 publications

(105 citation statements)

References 54 publications

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“…Neural pathways related to learning-memory formation are considered as plastic and dynamic networks and not as static wiring models, because feedback and feedforward interactions are known to exist in learning and specifically within the CTA circuitry (Katz et al, 2002;Lundy and Norgren, 2004). Furthermore, a hedonic neural circuit independent from sensory processes seems to be modified during CTA formation (Yamamoto et al, 1994a;Grancha et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Neural Substrates for Behaviorally Conditioned Immunosuppression in the Rat

Pacheco-López¹,

Niemi²,

Kou³

et al. 2005

J. Neurosci.

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We have previously demonstrated behaviorally conditioned immunosuppression using cyclosporin A as an unconditioned stimulus and saccharin as a conditioned stimulus. In the current study, we examined the central processing of this phenomenon generating excitotoxic lesions before and after acquisition to discriminate between learning and memory processes. Three different brain areas were analyzed: insular cortex (IC), amygdala (Am), and ventromedial nucleus of the hypothalamus (VMH). The results demonstrate that IC lesions performed before and after acquisition disrupted the behavioral component of the conditioned response (taste aversion). In contrast, Am and VMH lesions did not affect conditioned taste aversion. The behaviorally conditioned suppression of splenocyte proliferation and cytokine production (interleukin-2 and interferon-␥) was differentially affected by the excitotoxic lesions, showing that the IC is essential to acquire and evoke this conditioned response of the immune system. In contrast, the Am seems to mediate the input of visceral information necessary at the acquisition time, whereas the VMH appears to participate within the output pathway to the immune system necessary to evoke the behavioral conditioned immune response. The present data reveal relevant neural mechanisms underlying the learning and memory processes of behaviorally conditioned immunosuppression.

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Section: Discussionmentioning

confidence: 99%

Neural Substrates for Behaviorally Conditioned Immunosuppression in the Rat

Pacheco-López¹,

Niemi²,

Kou³

et al. 2005

J. Neurosci.

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“…We suggest that both properties may be used to encode changes in concentration. We speculate that, in response to concentration changes, such varied behavior could be a consequence of the fact that GC receives (and transmits) information from other cortical and subcortical areas (Smith and Li, 2000;Lundy and Norgren, 2004) and that these areas will respond differentially to different tastants and concentrations of tastants. In particular, tastants such as quinine and sucrose possess different hedonic valences, so additional networks may be recruited to reflect different palatabilities (Small et al, 2003;Sewards, 2004).…”

Section: Codingmentioning

confidence: 99%

Rapid Taste Responses in the Gustatory Cortex during Licking

Stapleton¹,

Lavine²,

Wolpert³

et al. 2006

J. Neurosci.

133

149

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Rapid tastant detection is necessary to prevent the ingestion of potentially poisonous compounds. Behavioral studies have shown that rats can identify tastants in ϳ200 ms, although the electrophysiological correlates for fast tastant detection have not been identified. For this reason, we investigated whether neurons in the primary gustatory cortex (GC), a cortical area necessary for tastant identification and discrimination, contain sufficient information in a single lick cycle, or ϳ150 ms, to distinguish between tastants at different concentrations. This was achieved by recording neural activity in GC while rats licked four times without a liquid reward, and then, on the fifth lick, received a tastant (FR5 schedule). We found that 34% (61 of 178) of GC units were chemosensitive. The remaining neurons were activated during some phase of the licking cycle, discriminated between reinforced and unreinforced licks, or processed task-related information. Chemosensory neurons exhibited a latency of 70 -120 ms depending on concentration, and a temporally precise phasic response that returned to baseline in tens of milliseconds. Tastant-responsive neurons were broadly tuned and responded to increasing tastant concentrations by either increasing or decreasing their firing rates. In addition, some responses were only evoked at intermediate tastant concentrations. In summary, these results suggest that the gustatory cortex is capable of processing multimodal information on a rapid timescale and provide the physiological basis by which animals may discriminate between tastants during a single lick cycle.

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“…These forebrain nuclei likely have a role in gustatory modulation of the cells in the PbN. Indeed, electrophysiological investigations have reported that gustatory responses of pontine neurons are modulated by electrical stimulation of the LH, CeA, and GC in the hamster and the rat (11,35,39,40).The VPMpc, the third-order gustatory relay in the rodent, is less understood in several aspects (56,68,85,86). For example, whereas the afferent projections from the PbN to the VPMpc were well documented, the efferent projections from the VPMpc to the PbN were not demonstrated (4,21,64).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Modulation of activity of gustatory neurons in the hamster parabrachial nuclei by electrical stimulation of the ventroposteromedial nucleus of the thalamus

Mao¹,

Cho²,

Li³

2008

American Journal of Physiology-Regulatory, Integrative and Comp

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(VPMpc) is positioned at the key site between the gustatory parabrachial nuclei (PbN) and the gustatory cortex for relaying and processing gustatory information via the thalamocortical pathway. Although neuroanatomical and electrophysiological studies have provided information regarding the gustatory projection from PbN to VPMpc, the exact relationship between PbN and VPMpc, especially the efferent projection involving VPMpc to PbN, is obscure. Here we investigated the reciprocal connection between these two gustatory relays in urethaneanesthetized hamsters. We recorded from 114 taste-responsive neurons in the PbN and examined their responsiveness to electrical stimulation of the VPMpc bilaterally. Stimulation of either or both of the ipsilateral or contralateral VPMpc antidromically activated 109 gustatory PbN neurons. Seventy-two PbN neurons were antidromically activated after stimulation of both sides of the VPMpc, indicating that taste neurons in the PbN project heavily to the bilateral VPMpc. Stimulation of VPMpc also orthodromically activated 110 of PbN neurons, including 106 VPMpc projection neurons. Seventyeight neurons were orthodromically activated bilaterally. Among orthodromic activations of the PbN cells, the inhibitory response was the dominant response; 106 cells were inhibited, including 10 neurons that were also excited contralaterally, indicating that taste neurons in the PbN are subject to strong inhibitory control from VPMpc. Moreover, stimulation of VPMpc altered taste responses of the neurons in the PbN, indicating that VPMpc modulates taste responses of PbN neurons. These results may provide functional insight of neural circuitry for taste processing and modulation involving these two nuclei.central gustatory pathway; pons; electrophysiology THE PARABRACHIAL NUCLEI (PbN) and the parvicellular part of the ventroposteromedial nucleus of the thalamus (VPMpc) are the second and tertiary central relays for taste information processing in rodents, respectively (4,13,17,28,45,49,51). Gustatory information elicited from the tongue and oropharyngeal cavity is initially carried to the rostral portion of the nucleus of the solitary tract (NST) by the VIIth, IXth, and Xth cranial nerves, and these terminals are distributed in a topographic fashion with rostral-caudal sequence in the rostral NST (2,9,23,24,89). From the NST, ascending gustatory fibers project to third-order taste cells within the PbN of the pons (7,22,42,46,(53)(54)(55)87). Two separate routes carry taste information from the PbN further to the forebrain taste areas and cortex: the ventral forebrain pathway that involves the central nucleus of the amygdala (CeA), the lateral hypothalamus (LH), the bed nucleus of the stria terminalis (BNST), the substantia innominata (3,12,16,21,31,33,34,41,47,63,64,71); and the thalamocortical pathway that is characterized by the involvement of the bilateral VPMpc, which, in turn, carries taste information to the gustatory cortex (GC) (5,25,45,48,51).The PbN is a critical neural substrate for a number...

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Activity in the Hypothalamus, Amygdala, and Cortex Generates Bilateral and Convergent Modulation of Pontine Gustatory Neurons

Cited by 101 publications

References 54 publications

Neural Substrates for Behaviorally Conditioned Immunosuppression in the Rat

Neural Substrates for Behaviorally Conditioned Immunosuppression in the Rat

Rapid Taste Responses in the Gustatory Cortex during Licking

Modulation of activity of gustatory neurons in the hamster parabrachial nuclei by electrical stimulation of the ventroposteromedial nucleus of the thalamus

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