Monosynaptic convergence of chorda tympani and glossopharyngeal afferents onto ascending relay neurons in the nucleus of the solitary tract: A high‐resolution confocal and correlative electron microscopy approach

Corson, James A.; Erişir, Alev

doi:10.1002/cne.23357

Cited by 27 publications

(28 citation statements)

References 61 publications

(77 reference statements)

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“…Linear fluorescence profiles show that synaptic elements that appear connected at the resolution of the diffraction limit of ∼300 nm (Fig. G), consistent with past analyses based on apposing elements (Corson and Erisir, ). We counted 466 putative synapses in ∼7.7 × 10 6 μm 3 of representative SpVm confocal volumes; due to sparse labeling, one synapse per (25 μm) 3 represents a lower bound on the density of putative synapses.…”

Section: Resultssupporting

confidence: 89%

Feedback in the brainstem: An excitatory disynaptic pathway for control of whisking

Matthews

Deschênes

Furuta

et al. 2015

J of Comparative Neurology

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Sensorimotor processing relies on hierarchical neuronal circuits to mediate sensory-driven behaviors. In the mouse vibrissa system, trigeminal brainstem circuits are thought to mediate the first stage of vibrissa scanning control via sensory feedback that provides reflexive protraction in response to stimulation. However, these circuits are not well defined. Here, we describe a complete disynaptic sensory receptor-to-muscle circuit for positive feedback in vibrissa movement. We identified a novel region of trigeminal brainstem, spinal trigeminal nucleus pars muralis, that contains a class of vGluT2+ excitatory projection neurons involved in vibrissa motor control. Complementary single- and duallabeling with traditional and virus tracers demonstrate that these neurons both receive primary inputs from vibrissa sensory afferent fibers and send monosynaptic connections to facial nucleus motoneurons that directly innervate vibrissa musculature. These anatomical results suggest a general role of disynaptic architecture in fast positive feedback for motor output driving active sensation.

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Section: Resultssupporting

confidence: 89%

Feedback in the brainstem: An excitatory disynaptic pathway for control of whisking

Matthews

Deschênes

Furuta

et al. 2015

J of Comparative Neurology

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“…These studies have focused on the chorda tympani (CT) nerve, which innervates taste receptors on only the anterior tongue. Neurons in rostral regions of the NTS can receive convergent input from afferents innervating gustatory epithelia located on different regions of the tongue and mouth (Corson and Erisir 2013;Grabauskas and Bradley 1996;Travers et al 1986;Travers and Norgren 1995), which were broadly bathed with solutions by our taste stimulation method (Wilson et al 2012). Along this line, there exist similarities and differences between prior peripheral data and the present central data on thermo-concentration effects on gustatory activity to sucrose.…”

Section: Cooling and Concentration Effectsmentioning

confidence: 53%

Temperature systematically modifies neural activity for sweet taste

Wilson

Lemon

2014

Journal of Neurophysiology

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Wilson DM, Lemon CH. Temperature systematically modifies neural activity for sweet taste. J Neurophysiol 112: 1667-1677, 2014. First published June 25, 2014 doi:10.1152 doi:10. /jn.00368.2014 can modify neural and behavioral responses to taste stimuli that elicit "sweetness," a perception linked to intake of calorie-laden foods. However, the role of temperature in the neural representation of sweet taste is poorly understood. Here we made electrophysiological recordings from gustatory neurons in the medulla of inbred mice to study how adjustments in taste solution temperature to cool (18°C), ambient (22°C), and warm (30°C and 37°C) values changed the magnitude and latency of gustatory activity to sucrose (0, 0.05, 0.1, 0.17, 0.31, and 0.56 M). Analysis of 22 sucrose-best neurons revealed that temperature markedly influenced responses to sucrose, which, across concentrations, were largest when solutions were warmed to 30°C. However, reducing solution temperature from warm to ambient to cool progressively steepened the slope of the sucrose concentrationresponse function computed across cells (P Ͻ 0.05), indicating that mean activity to sucrose increased more rapidly with concentration steps under cooling than with warming. Thus the slope of the sucrose concentration-response function shows an inverse relation with temperature. Temperature also influenced latency to the first spike of the sucrose response. Across neurons, latencies were shorter when sucrose solutions were warmed and longer, by hundreds of milliseconds, when solutions were cooled (P Ͻ 0.05), indicating that temperature is also a temporal parameter of sucrose activity. Our findings reveal that temperature systematically modifies the timing of gustatory activity to sucrose in the mammalian brain and how this activity changes with concentration. Results further highlight how oral somatosensory cues function as physiological modulators of gustatory processing. taste; sucrose; temperature; latency; coding THE STUDY OF NEURAL CODING involves, in part, relating features of sensory stimuli to neural activity. For taste, this pursuit has largely focused on two stimulus features: the perceptual quality of the taste chemical and its concentration while dissolved in solution. Taste quality is a descriptive characteristic of taste stimuli transmitted, in part, through substitution (cf. Stevens 1961) of responses by different neurons. For instance, exchanging a taste stimulus of one quality (e.g., "sweet") for another (e.g., "salty") can cause a substitutive change in the neurons that respond maximally to the stimulus, leading to an associated change in the evoked response pattern. Concentration, on the other hand, is a physical property of taste stimuli that guides the magnitude of gustatory responses.Temperature is an additional physical property of taste stimuli that can modulate gustatory processing. Temperature strongly influences neural and behavioral responses to sweet stimuli. Gustatory activity to sucrose in peripheral nerves carrying sensory input fro...

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“…As it is highly unlikely that we failed to stimulate the anterior tongue (innervated by chorda tympani), this discrepancy may reflect the different information processing or neural coding strategy of umami taste in the periphery vs. brain. In fact, physiological and anatomical studies in rodents indicate that inputs from the chorda tympani and glossopharyngeal nerves converge at the level of the NST, which likely differentiates central gustatory responsiveness from that in the periphery, and may account for the present discrepancy (Travers et al, 1986; Sweazey and Smith, 1987; Travers and Norgren, 1995; Grabauskas and Bradley, 1996; Corson and Erisir, 2013). Another possibility, however, is that we failed to optimally stimulate the posterior tongue.…”

Section: Discussionmentioning

confidence: 87%

Topographic organizations of taste-responsive neurons in the parabrachial nucleus of C57BL/6J mice: An electrophysiological mapping study

Tokita

Boughter

2016

Neuroscience

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The activities of 178 taste-responsive neurons were recorded extracellularly from the parabrachial nucleus (PbN) in the anesthetized C57BL/6J mouse. Taste stimuli included those representative of 5 basic taste qualities, sweet, salty, sour, bitter and umami. Umami synergism was represented by all sucrose-best and sweet-sensitive sodium chloride-best neurons. Mediolaterally the PbN was divided into medial, brachium conjunctivum (BC) and lateral subdivisions while rostrocaudally the PbN was divided into rostral and caudal subdivisions for mapping and reconstruction of recording sites. Neurons in the medial and BC subdivisions had a significantly greater magnitude of response to sucrose and to the mixture of monopotassium glutamate and inosine monophosphate than those found in the lateral subdivision. In contrast, neurons in the lateral subdivision possessed a more robust response to quinine hydrochloride. Rostrocaudally no difference was found in the mean magnitude of response. Analysis on the distribution pattern of neuron types classified by their best stimulus revealed that the proportion of neuron types in the medial vs. lateral and BC vs. lateral subdivisions was significantly different, with a greater amount of sucrose-best neurons found medially and within the BC, and a greater amount of sodium chloride-, citric acid- and quinine hydrochloride-best neurons found laterally. There was no significant difference in the neuron type distribution between rostral and caudal PbN. We also assessed breadth of tuning in these neurons by calculating entropy (H) and noise-to-signal (N/S) ratio. Mean N/S ratio of all neurons (0.43) was significantly lower than that of H value (0.64). Neurons in the caudal PbN had a significantly higher H value than in the rostral PbN. In contrast, mean N/S ratio were not different both mediolaterally and rostrocaudally. These results suggest that although there is overlap in taste quality representation in the mouse PbN, taste-responsive neurons still possessed a topographic organization.

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Monosynaptic convergence of chorda tympani and glossopharyngeal afferents onto ascending relay neurons in the nucleus of the solitary tract: A high‐resolution confocal and correlative electron microscopy approach

Cited by 27 publications

References 61 publications

Feedback in the brainstem: An excitatory disynaptic pathway for control of whisking

Feedback in the brainstem: An excitatory disynaptic pathway for control of whisking

Temperature systematically modifies neural activity for sweet taste

Topographic organizations of taste-responsive neurons in the parabrachial nucleus of C57BL/6J mice: An electrophysiological mapping study

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