Taste-responsive neurons in the nucleus of the solitary tract receive gustatory information from both sides of the tongue in the hamster

2008 ◽  
Vol 294 (2) ◽  
pp. R372-R381 ◽  
Author(s):  
Cheng-Shu Li ◽  
Limin Mao ◽  
Young K. Cho
Keyword(s):  
Chorda Tympani ◽  
Solitary Tract ◽  
Subjective Change ◽  
Left And Right ◽  
Parabrachial Nuclei ◽  
Excitatory Responses ◽  
Gustatory Information ◽  
Taste Stimulation ◽  
Inhibitory Interactions ◽  
Taste Experience

Taste receptors on the left and right sides of the anterior tongue are innervated by chorda tympani (CT) fibers, which carry taste information to the ipsilateral nucleus of the solitary tract (NST). Although the anterior tongue is essential for taste, patients with unilateral CT nerve damage often report no subjective change in their taste experience. The standing theory that explains the taste constancy is the “release of inhibition”, which hypothesizes that within the NST there are inhibitory interactions between inputs from the CT and glossopharyngeal nerves and that the loss of taste information from the CT is compensated by a release of inhibition on the glossopharyngeal nerve input. However, the possibility of compensation by taste input from the other side of the tongue has never been investigated in rodents. We recorded from 95 taste-responsive neurons in the NST and examined their responsiveness to stimulation of the contralateral CT. Forty-six cells were activated, mostly with excitatory responses (42 cells). Activation of NST cells induced by contralateral CT stimulation was blocked by microinjection of lidocaine into the contralateral NST but was not affected by anesthetization of the contralateral parabrachial nuclei (PbN). In addition, the NST cells that were activated by contralateral CT stimulation showed reduced responsiveness to taste stimulation after microinjection of lidocaine into the contralateral NST. These results demonstrate that nearly half of the taste neurons in the NST receive gustatory information from both sides of the tongue. This “cross talk” between bilateral NST may also contribute to the “taste constancy”.

Parabrachial units responding to stimulation of buffer nerves and forebrain in the cat

1983 ◽  
Vol 245 (6) ◽  
pp. R811-R819 ◽  
Author(s):  
D. F. Cechetto ◽  
F. R. Calaresu
Keyword(s):  
Nerve Stimulation ◽  
Carotid Sinus ◽  
Respiratory Control ◽  
Firing Frequency ◽  
Central Nucleus ◽  
Paraventricular Nuclei ◽  
Control Signals ◽  
Parabrachial Nuclei ◽  
Excitatory Responses ◽  
Stimulation Of

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.

Roles of Inhibition in Creating Complex Auditory Responses in the Inferior Colliculus: Facilitated Combination-Sensitive Neurons

2005 ◽  
Vol 93 (6) ◽  
pp. 3294-3312 ◽  
Author(s):  
Kiran Nataraj ◽  
Jeffrey J. Wenstrup
Keyword(s):  
Brain Stem ◽  
Inferior Colliculus ◽  
Low Frequency ◽  
Auditory Responses ◽  
Auditory Brain Stem ◽  
Neural Interactions ◽  
Lower Brain Stem ◽  
Excitatory Responses ◽  
Sonar Echoes ◽  
Inhibitory Interactions

We studied roles of inhibition on temporally sensitive facilitation in combination-sensitive neurons from the mustached bat's inferior colliculus (IC). In these integrative neurons, excitatory responses to best frequency (BF) tones are enhanced by much lower frequency signals presented in a specific temporal relationship. Most facilitated neurons (76%) showed inhibition at delays earlier than or later than the delays causing facilitation. The timing of inhibition at earlier delays was closely related to the best delay of facilitation, but the inhibition had little influence on the duration or strength of the facilitatory interaction. Local iontophoretic application of antagonists to receptors for glycine (strychnine, STRY) and γ-aminobutyric acid (GABA) (bicuculline, BIC) showed that STRY abolished facilitation in 96% of tested units, but BIC eliminated facilitation in only 28%. This suggests that facilitatory interactions are created in IC and reveals a differential role for these neurotransmitters. The facilitation may be created by coincidence of a postinhibitory rebound excitation activated by the low-frequency signal with the BF-evoked excitation. Unlike facilitation, inhibition at earlier delays was not eliminated by application of antagonists, suggesting an origin in lower brain stem nuclei. However, inhibition at delays later than facilitation, like facilitation itself, appears to originate within IC and to be more dependent on glycinergic than GABAergic mechanisms. Facilitatory and inhibitory interactions displayed by these combination-sensitive neurons encode information within sonar echoes and social vocalizations. The results indicate that these complex response properties arise through a series of neural interactions in the auditory brain stem and midbrain.

Gustatory responses of neurons in the nucleus of the solitary tract of behaving rats

1991 ◽  
Vol 66 (4) ◽  
pp. 1232-1248 ◽  
Author(s):  
K. Nakamura ◽  
R. Norgren
Keyword(s):  
Citric Acid ◽  
Dimensional Space ◽  
Hierarchical Cluster ◽  
Stimulus Category ◽  
Solitary Tract ◽  
Spontaneous Rate ◽  
Taste Response ◽  
The Mean ◽  
Excitatory Responses ◽  
Gustatory Neurons

1. The activity of 117 single neurons was recorded in the rostral nucleus of the solitary tract (NST) and tested with each of four standard chemical stimuli [sucrose, NaCl, citric acid, and quinine HCl (QHCl)] and distilled water in awake, behaving rats. In 101 of these neurons, at least one sapid stimulus elicited a significant taste response. The mean spontaneous rate of the taste neurons was 4.1 +/- 5.8 (SD) spike/s. The mean response magnitudes were as follows: sucrose, 10.6 +/- 11.7; NaCl, 8.6 +/- 14.6; citric acid, 6.2 +/- 7.8; and QHCl, 2.4 +/- 6.6 spikes/s. 2. On the basis of their largest response, 42 taste neurons were classified as sucrose-best, 25 as NaCl-best, 30 as citric acid-best, and 4 as QHCl-best. The mean spontaneous rates for these categories were 4.9 +/- 6.2 for sucrose-best cells, 5.8 +/- 7.4 for NaCl-best, 1.6 +/- 2.0 for citric acid-best, and 5.8 +/- 6.0 spikes/s for QHCl-best. The spontaneous rate of the citric acid-best neurons was significantly lower than that of the other categories. 3. At the standard concentrations, 45 taste cells (44.6%) responded significantly to only one of the gustatory stimuli. Of the 30 acid-best neurons, 23 (76.7%) responded only to citric acid. For sucrose-best cells, specific sensitivity was less common (18/42, 42.9%), and for NaCl-best neurons, it was relatively uncommon (3/25, 12%). One of the 4 QHCl-best neurons was specific. In a concentration series, more than one-half of the 19 specific neurons tested responded to only one chemical at any strength. 4. The mean entropy for the excitatory responses of all gustatory neurons was 0.60. Citric acid-best cells showed the least breadth of responsiveness (0.49), sucrose-best cells were somewhat broader (0.56), but NaCl-best and QHCl-best cells were considerably less selective (0.77 and 0.79, respectively). Inhibition was observed infrequently and never reached the criterion for significance. 5. In the hierarchical cluster analysis, the four largest clusters segregated neurons primarily by best-stimulus category. The major exception to this was a group of sucrose-best neurons that also responded to NaCl and were grouped with the NaCl-best neurons. In a two-dimensional space, the specific taste neurons, those that responded to only one of the four standard sapid stimuli, remained in well-separated groups. These specific groups, however, were joined in a ring-like formation by other neurons that responded to more than one of the sapid stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Nucleus of the solitary tract in the C57BL/6J mouse: Subnuclear parcellation, chorda tympani nerve projections, and brainstem connections

2014 ◽  
Vol 522 (7) ◽  
pp. 1565-1596 ◽  
Author(s):  
Donald Ganchrow ◽  
Judith R. Ganchrow ◽  
Vanessa Cicchini ◽  
Dianna L. Bartel ◽  
Daniel Kaufman ◽  
...  
Keyword(s):  
Chorda Tympani ◽  
Solitary Tract ◽  
Chorda Tympani Nerve

Laryngeal afferent inputs to the nucleus of the solitary tract

1993 ◽  
Vol 265 (2) ◽  
pp. R269-R276 ◽  
Author(s):  
S. W. Mifflin
Keyword(s):  
Stimulus Frequency ◽  
Time Dependent ◽  
Excitatory Postsynaptic Potential ◽  
Solitary Tract ◽  
Neuronal Responses ◽  
Epsp Amplitude ◽  
Postsynaptic Potential ◽  
Afferent Inputs ◽  
Inhibitory Interactions ◽  
Stimulation Of

The following study was undertaken to examine the integration of laryngeal afferent inputs within the nucleus of the solitary tract (NTS), the primary site of termination of laryngeal afferent fibers. Intracellular recordings were obtained from 63 cells that responded to electrical stimulation of the superior laryngeal nerve (SLN) with an excitatory postsynaptic potential (EPSP; n = 49), an excitatory-inhibitory postsynaptic potential (EPSP-IPSP) sequence (n = 13), or an IPSP (n = 1). Mechanical stimulation of laryngeal mechanoreceptors revealed a variety of response patterns (e.g., slowly and rapidly adapting depolarizations or hyperpolarizations). Two types of response to increasing SLN stimulus frequency were observed. In 11 cells SLN-evoked EPSP amplitude at 10 Hz was only 47 +/- 4% of the amplitude at 1 Hz, while in 6 cells EPSP amplitude at 10 Hz was virtually identical (93 +/- 3%) to that at 1 Hz. Time-dependent inhibitory interactions occurred between SLN inputs to NTS neurons at intervals between 50 and 400 ms and in the absence of any change in membrane potential. NTS neuronal responses to brief activation of laryngeal mechanoreceptors correspond well to discharge patterns described for individual laryngeal mechanoreceptors. Frequency-dependent filtering and time-dependent inhibitory interactions might modify NTS neuronal responses during more intense stimulation of laryngeal afferents.

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