scholarly journals Responsiveness of neurons in the hamster parabrachial nuclei to taste mixtures.

1984 ◽  
Vol 84 (2) ◽  
pp. 221-250 ◽  
Author(s):  
S P Travers ◽  
D V Smith

Responses from hamster parabrachial nuclei neurons to stimulation of the anterior tongue with sucrose, NaCl, HCl, quinine hydrochloride, and the six two-component mixtures of these stimuli were recorded. A cell's response to a mixture approached its response to the mixture's more effective component in the majority of cases, but was sometimes greater or smaller than this response. The best predictor of a neuron's response to a mixture, then, was its response to the mixture's more effective component. The single-component stimulus producing the maximum response was determined for each neuron and the response to this stimulus was compared with the responses evoked by the six mixtures. For 30% of the cells, a mixture elicited a response reliably, but only 1.1-2.1 times greater than the response to the best single-component stimulus. Thus, there were no neurons specialized to respond to these mixtures. The across-neuron patterns elicited by mixtures and the responses of best-stimulus classes to mixtures were studied for comparison with psychophysical data on taste mixtures. Mixtures were usually correlated with single-component stimuli in the mixture, but not with stimuli not in the mixture. In fact, five of the six mixtures fell directly between their components in a multidimensional scaling plot. In addition, a mixture was most effective in stimulating only those classes of neurons maximally stimulated by the mixture's components. These results correlate with psychophysical data suggesting that mixtures of taste stimuli evoke the same taste qualities as evoked by the mixture's components.

2005 ◽  
Vol 93 (3) ◽  
pp. 1183-1196 ◽  
Author(s):  
Cheng-Shu Li ◽  
Young K. Cho ◽  
David V. Smith

The lateral hypothalamus (LH) and the central nucleus of the amygdala (CeA) exert an influence on ingestive behavior and are reciprocally connected to gustatory and viscerosensory areas, including the nucleus of the solitary tract (NST) and the parabrachial nuclei (PbN). We investigated the effects of LH and CeA stimulation on the activity of 101 taste-responsive neurons in the hamster PbN. Eighty three of these neurons were antidromically activated by stimulation of these sites; 57 were antidromically driven by both. Of these 83 neurons, 21 were also orthodromically activated—8 by the CeA and 3 by the LH. Additional neurons were excited ( n = 5) or inhibited ( n = 8) by these forebrain nuclei but not antidromically activated. Taste stimuli were: 0.032 M sucrose, 0.032 M sodium chloride (NaCl), 0.032 M quinine hydrochloride (QHCl), and 0.0032 M citric acid. Among the 34 orthodromically activated neurons, more sucrose-best neurons were excited than inhibited, whereas the opposite occurred for citric-acid- and QHCl-best cells. Neurons inhibited by the forebrain responded significantly more strongly to citric acid and QHCl than cells excited by these sites. The effects of electrical stimulation were mimicked by microinjection of dl-homocysteic acid, indicating that cells at these forebrain sites were responsible for these effects. These data demonstrate that many individual PbN gustatory neurons project to both the LH and CeA and that these areas modulate the gustatory activity of a subset of PbN neurons. This neural substrate is likely involved in the modulation of taste activity by physiological and experiential factors.


2012 ◽  
Vol 108 (5) ◽  
pp. 1288-1298 ◽  
Author(s):  
Cheng-Shu Li ◽  
Sooyoung Chung ◽  
Da-Peng Lu ◽  
Young K. Cho

The parabrachial nuclei (PbN), the second central relay for the gustatory pathway, transfers taste information to various forebrain gustatory nuclei and to the gustatory cortex. The nucleus accumbens is one of the critical neural substrates of the reward system, and the nucleus accumbens shell region (NAcSh) is associated with feeding behavior. Taste-evoked neuronal responses of PbN neurons are modulated by descending projections from the gustatory nuclei in the forebrain. In the present study, we investigated whether taste-responsive neurons in the PbN project to the NAcSh and whether pontine gustatory neurons are subject to modulatory influence from the NAcSh in urethane-anesthetized hamsters. Extracellular single-unit activity was recorded in the PbN, and taste responses were confirmed by the delivery of 32 mM sucrose, NaCl, quinine hydrochloride, and 3.2 mM citric acid to the anterior tongue. The NAcSh was then stimulated (0.5 ms, ≤100 μA) bilaterally using concentric bipolar stimulating electrodes. A total of 98 taste neurons were recorded from the PbN. Eighteen neurons were antidromically invaded from the NAcSh, mostly the ipsilateral NAcSh ( n = 16). Stimulation of the ipsilateral and contralateral NAcSh suppressed the neuronal activity of 88 and 55 neurons, respectively; 52 cells were affected bilaterally. In a subset of pontine neurons tested, electrical stimulation of the NAcSh during taste stimulation also suppressed taste-evoked neuronal firing. These results demonstrated that taste-responsive neurons in the PbN not only project to the NAcSh but also are under substantial descending inhibitory influence from the bilateral NAcSh.


2016 ◽  
Vol 120 (4) ◽  
pp. 615-621 ◽  
Author(s):  
V. Ya. Gotsul’skii ◽  
N. P. Malomuzh ◽  
V. E. Chechko

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Andrei Khilkevich ◽  
Juan Zambrano ◽  
Molly-Marie Richards ◽  
Michael Dean Mauk

Most movements are not unitary, but are comprised of sequences. Although patients with cerebellar pathology display severe deficits in the execution and learning of sequences (Doyon et al., 1997; Shin and Ivry, 2003), most of our understanding of cerebellar mechanisms has come from analyses of single component movements. Eyelid conditioning is a cerebellar-mediated behavior that provides the ability to control and restrict inputs to the cerebellum through stimulation of mossy fibers. We utilized this advantage to test directly how the cerebellum can learn a sequence of inter-connected movement components in rabbits. We show that the feedback signals from one component are sufficient to serve as a cue for the next component in the sequence. In vivo recordings from Purkinje cells demonstrated that all components of the sequence were encoded similarly by cerebellar cortex. These results provide a simple yet general framework for how the cerebellum can use simple associate learning processes to chain together a sequence of appropriately timed responses.


1983 ◽  
Vol 245 (6) ◽  
pp. R811-R819 ◽  
Author(s):  
D. F. Cechetto ◽  
F. R. Calaresu

Spontaneously firing units in the region of parabrachial nuclei (PB) and Kolliker-Fuse nuclei (KF) of 19 chloralose-anesthetized cats were monitored for changes in firing frequency during electrical stimulation of carotid sinus (CSN) and aortic depressor (ADN) nerves, of central nucleus of the amygdala (ACE), and of paraventricular nuclei of the hypothalamus (PVH). In the ipsilateral PB 64 of 189 and in the contralateral PB 9 of 103 units responded to CSN stimulation; 18 of 185 ipsilaterally and 7 of 97 contralaterally responded to ADN stimulation. Responses were primarily excitatory, and units were located primarily in the ventrolateral portion of the PB. Only 9 of 267 units responded to stimulation of both CSN and ADN. Stimulation of the ACE and PVH antidromically activated 9 and 7 units, respectively, in PB and approximately half of these also responded to buffer nerve stimulation. In the ipsilateral PB 56 of 207 and in the contralateral PB 11 of 103 units responded orthodromically to ACE stimulation, and 23 of 177 ipsilaterally and 2 of 103 contralaterally responded orthodromically to PVH stimulation with primarily excitatory responses and were located primarily in the ventrolateral portion of the PB and KF. Of these units approximately half also responded to buffer nerve stimulation. These results suggest an important role for PB-KF in mediating ascending and descending cardiovascular and respiratory control signals.


1987 ◽  
Vol 57 (2) ◽  
pp. 481-495 ◽  
Author(s):  
D. L. Hill

Extracellular responses from neurons in the parabrachial nuclei (PBN) were studied in rats 4 days old to adulthood during chemical stimulation of the tongue with monochloride salts, citric and hydrochloric acids, sucrose, sodium saccharin, and quinine hydrochloride. Multiunit taste responses were recorded in rats at 4-7 days of age and single-unit responses were recorded from 121 neurons in four other age groups of 14-20 days, 25-35 days, 50-60 days, and adults. PBN neurons in rats 4-7 days old consistently responded to 0.1 M solutions of NH4Cl and NaCl, to 0.5 M solutions of NH4Cl, NaCl, and KCl, and to 1.0 M sucrose, 0.1 M sodium saccharin, 0.1 M citric acid, and 0.1 N HCl. They often did not respond, however, to 0.1 M KCl and 0.01 M quinine hydrochloride. Single PBN neurons in rats 14 days old and older characteristically responded to all stimuli, which consisted of 0.1 and 0.5 M salts, acids, sucrose, sodium saccharin, and quinine hydrochloride. Thus no developmental differences occurred in the number of stimuli to which neurons responded after rats were 14 days old. With the exception of responses to hydrochloric acid, there were significant increases in response frequencies to all stimuli after 14 days of age. Average response frequencies to NH4Cl and citric acid increased after 20 days of age and those to NaCl, LiCl, KCl, sucrose, sodium saccharin, and quinine hydrochloride increased after 35 days of age. Average response frequencies for hydrochloric acid did not alter after 14 days of age. The proportion of single PBN neurons that responded maximally to specific monochloride salts did not change during development. Most single neurons in all age groups responded equally well to NH4Cl, NaCl, and LiCl. No PBN neuron responded maximally to KCl. Developmental differences in response frequencies of third-order gustatory neurons in the PBN generally reflect developmental response changes in first-order neurons of the chorda tympani nerve and second-order neurons of the solitary nucleus. However, unique developmental changes are evident in the PBN. Thus the ontogenetic changes that occur in PBN responses likely relate to modifications of lower-order peripheral and central nervous system afferents and peripheral receptor sensitivities.


1994 ◽  
Vol 477 (2) ◽  
pp. 321-329 ◽  
Author(s):  
J P Lara ◽  
M J Parkes ◽  
L Silva-Carvhalo ◽  
P Izzo ◽  
M S Dawid-Milner ◽  
...  

2008 ◽  
Vol 99 (5) ◽  
pp. 2144-2157 ◽  
Author(s):  
Jen-Yung Chen ◽  
Patricia M. Di Lorenzo

The contribution of gustation to the perception of food requires an understanding of how neurons represent mixtures of taste qualities. In the periphery, separate groups of fibers, labeled by the stimulus that evokes the best (largest) response, appear to respond to each component of a mixture. In the brain, identification of analogous groups of neurons is hampered by trial-to-trial variability in response magnitude. In addition, convergence of different fiber types onto central neurons may complicate the classification scheme. To investigate these issues, electrophysiological responses to four tastants: sucrose, NaCl, HCl, and quinine, and their binary mixtures were recorded from 56 cells in the nucleus of the solitary tract (NTS, the 1st synapse in the central gustatory pathway) of the anesthetized rat. For 36 of these cells, all 10 stimuli were repeated at least five times (range: 5–23; median = 10). Results showed that 39% of these cells changed their best stimulus across stimulus repetitions, suggesting that response magnitude (firing rate) on any given trial produces an ambiguous message. Averaged across replicate trials, mixture responses most often approximated the response to the more effective component of the mixture. Cells that responded best to a taste mixture rather than any single-component tastant were identified. These cells were more broadly tuned than were cells that responded best to single-component stimuli and showed evidence of convergence from more than one best stimulus fiber type. Functionally, mixture-best cells may amplify the neural signal produced by unique configurations of basic taste qualities.


1980 ◽  
Vol 5 (2) ◽  
pp. 116-125 ◽  
Author(s):  
S. E. Wixson

This study describes and compares the variety and magnitude of the assessment, programming, and instructional services provided by single component and two component resource room delivery models. A rationale for a non-statistical approach to the assessment of program efficacy is presented and utilized. The results obtained indicate that the two component (direct and indirect service) resource room model sucessfully serves a greater number of pupils than the direct services only model. However, the two component model achieved fewer successful program completions in the direct services component than did the single component model. Overall, the results indicate that the resource program models utilized in this study are effective and efficient means for the delivery of services to pupils characterized as learning and/or behaviorally disordered. The results also suggest that many learning and/or behaviorally disordered pupils now served in self-contained special class settings could be effectively served in the less restrictive environment of a resource program.


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