scholarly journals Learning-based recovery from perceptual impairment in salt discrimination after permanently altered peripheral gustatory input

2010 ◽  
Vol 299 (4) ◽  
pp. R1027-R1036 ◽  
Author(s):  
Ginger Blonde ◽  
Enshe Jiang ◽  
Mircea Garcea ◽  
Alan C. Spector
Keyword(s):  
Facial Nerve ◽  
Superior Laryngeal Nerve ◽  
Taste Buds ◽  
Nerve Branch ◽  
Salt Taste ◽  
Sham Surgery ◽  
Significant Impairment ◽  
Taste Discrimination ◽  
Salt Taste Discrimination ◽  
Perceptual Impairment

Rats lacking input to the chorda tympani (CT) nerve, a facial nerve branch innervating anterior tongue taste buds, show robust impairments in salt discrimination demonstrating its necessity. We tested the sufficiency of the CT for salt taste discrimination and whether the remaining input provided by the greater superficial petrosal (GSP) nerve, a facial nerve branch innervating palatal taste buds, or by the glossopharyngeal (GL) nerve, innervating posterior tongue taste buds, could support performance after extended postsurgical testing. Rats presurgically trained and tested in a two-response operant task to discriminate NaCl from KCl were subjected to sham surgery or transection of the CT (CTx), GL (GLx), or GSP (GSPx), alone or in combination. While initially reduced postsurgically, performance by rats with an intact GSP after CTx + GLx increased to normal over 6 wk of testing. Rats with CTx + GSPx consistently performed near chance levels. In contrast, rats with GSPx + GLx were behaviorally normal. A subset of rats subjected to sham surgery and exposed to lower concentrations during postsurgical testing emulating decreased stimulus intensity after neurotomy showed no significant impairment. These results demonstrate that CTx changes the perceptual nature of NaCl and/or KCl, leading to severe initial postsurgical impairments in discriminability, but a “new” discrimination can be relearned based on the input of the GSP. Despite losing ∼75% of their taste buds, rats are unaffected after GSPx + GLx, demonstrating that the CT is not only necessary, but also sufficient, for maintaining salt taste discrimination, notwithstanding the unlikely contribution of the small percentage of taste receptors innervated by the superior laryngeal nerve.

Salt taste discrimination after bilateral section of the chorda tympani or glossopharyngeal nerves

1992 ◽  
Vol 263 (1) ◽  
pp. R169-R176 ◽  
Author(s):  
A. C. Spector ◽  
H. J. Grill
Keyword(s):  
Discrimination Performance ◽  
Taste Buds ◽  
Glossopharyngeal Nerve ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Salt Taste ◽  
Critical Elements ◽  
Electrophysiological Findings ◽  
Taste Discrimination ◽  
Salt Taste Discrimination

Gustatory deafferentation of the anterior tongue by bilateral section of the chorda tympani nerve, which removes only 15% of the total taste buds in the rat, severely impaired the rat's ability to discriminate NaCl from KCl. The discrimination deficit was selective. Denervated rats were able to discriminate sucrose from quinine. Despite eliminating four times as many taste buds by bilateral section of the glossopharyngeal nerve, posterior lingual deafferentation had no effect on NaCl vs. KCl discrimination performance. Collectively, these data suggest that afferents in the chorda tympani nerve provide the highest degree of disparity between the peripheral signals representing NaCl and KCl. Electrophysiological findings of others implicate the sodium-specific afferents that appear to exclusively exist in the chorda tympani nerve as the critical elements subserving the NaCl vs. KCl discrimination.

Functional status of the regenerated chorda tympani nerve as assessed in a salt taste discrimination task

2000 ◽  
Vol 278 (3) ◽  
pp. R720-R731 ◽  
Author(s):  
Stacy L. Kopka ◽  
Laura C. Geran ◽  
Alan C. Spector
Keyword(s):  
Functional Status ◽  
Nerve Regeneration ◽  
Discrimination Task ◽  
Discrimination Performance ◽  
Dependent Manner ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Sham Surgery ◽  
Taste Discrimination ◽  
Salt Taste Discrimination

We tested whether the recovered ability of rats to discriminate NaCl from KCl after chorda tympani nerve transection (CTX) is causally linked to nerve regeneration or some other compensatory process. Rats were presurgically trained in an operant NaCl vs. KCl discrimination task. Rats with regenerated nerves, histologically confirmed by anterior tongue taste pore counts and tested 62 days after CTX (CTX-62R; n = 5), performed as well as those tested 62 days after sham surgery (Sham-62; n = 5), but both of these groups initially performed slightly worse than animals tested 7 days after sham surgery (Sham-7; n = 4). Performance of rats tested either 7 (CTX-7P; n = 5) or 62 (CTX-62P; n = 4) days after CTX in which nerve regeneration was prevented was severely disrupted. Adulteration of the stimuli with amiloride, an epithelial sodium channel blocker, impaired discrimination performance in a similar dose-dependent manner in the Sham-7 ( n = 2), Sham-62 ( n = 5), and CTX-62R ( n = 5) groups, suggesting that the functional status of the amiloride-sensitive transduction pathway returns to normal in rats with regenerated chorda tympani nerves. Performance of CTX rats without regenerated nerves (CTX-7P, n = 2; CTX-62P, n = 4) was further degraded by amiloride treatment, suggesting that taste receptors innervated by other nerves are sensitive to amiloride. In conclusion, nerve regeneration is an essential component underlying full recovery of salt discrimination function after CTX.

Lingual deficits in BDNF and NT3 mutant mice leading to gustatory and somatosensory disturbances, respectively

Development ◽  
1997 ◽  
Vol 124 (7) ◽  
pp. 1333-1342 ◽  
Author(s):  
C.A. Nosrat ◽  
J. Blomlof ◽  
W.M. ElShamy ◽  
P. Ernfors ◽  
L. Olson
Keyword(s):  
Taste Buds ◽  
Mutant Mice ◽  
Taste Bud ◽  
Physiological Data ◽  
Clinical Implications ◽  
Wild Type ◽  
Severe Reduction ◽  
Sensory Modalities ◽  
Per Se ◽  
Taste Discrimination

A combination of anatomical, histological and physiological data from wild-type and null-mutated mice have established crucial roles for BDNF and NT3 in gustatory and somatosensory innervation of the tongue, and indeed for proper development of the papillary surface of the tongue. BDNF is expressed in taste buds, NT3 in many surrounding epithelial structures. Absence of BDNF in mice leads to severely malformed taste bud-bearing papillae and severe reduction of taste buds, a loss of proper innervation of remaining taste buds and a loss of taste discrimination although not of the suckling reflex per se. In contrast, absence of NT3 leads to a massive loss of somatosensory innervation of lingual structures. These findings demonstrate distinct roles for BDNF and NT3 in the establishment of the complex innervation apparatus of the tongue with non-overlapping roles for the lingual gustatory and somatosensory systems. The distinction between different sensory modalities, being dependent on either BDNF or NT3 may also have clinical implications.

Acute vs late extracranial facial nerve branch(s) repair: A comparative study

2019 ◽  
Vol 57 (10) ◽  
pp. e91
Author(s):  
Alexander Hills ◽  
Brian Bisase ◽  
Paul Norris ◽  
Karan Kapoor ◽  
Mike Shelley ◽  
...  
Keyword(s):  
Comparative Study ◽  
Facial Nerve ◽  
Nerve Branch

Traumatic injuries to the facial nerve: diagnosis and assistance

2020 ◽  
pp. 7-13
Author(s):  
Marufzhon Kh. KADYROV ◽  
Gafur M. KHODZHAMURADOV ◽  
Maksudzhon M. KADYROV ◽  
Mirali F. ODINAEV
Keyword(s):  
Facial Nerve ◽  
Complete Recovery ◽  
Partial Recovery ◽  
Main Trunk ◽  
Nerve Branch ◽  
Surgical Interventions ◽  
Traumatic Injuries ◽  
Nerve Suture ◽  
The Face ◽  
Surgical Treatments

We performed detection, examination and surgical treatment of trauma injuries of the main trunk or branches of the facial nerve among 16 patients. The main complaints of patients were related to aesthetic defects of tissues and organs within certain areas of the face or the whole half on the side of the injury and their functional disorders. The most frequent cause of injury was yatrogenic nerve damage. In the case of yatrogenic causes of injury, there are following groups of surgical interventions: surgery of the peritoneal salivary gland; aesthetic operations of the face in case of pathological processes or traumatic injuries of the temporal-lower joint and lower zone of the face. The following surgical treatments were used to repair damage to facial nerve structures: nerve suture; transposition of facial nerve branches; neuroplasticity; miofastsialny plasticity; neuroplasty in combination with the transplant of the revascularized neuromuscular transplant of the gentle soapy. In the distant postoperative period, complete recovery of facial nerve branch function and effectors, respectively, occurred among 10 patients. Partial recovery of their function - among 3 patients and recovery were absent among 3 clinical cases.

Pathogenesis of Bell's Palsy

1977 ◽  
Vol 86 (4) ◽  
pp. 549-558 ◽  
Author(s):  
Ruth Gussen
Keyword(s):  
Facial Nerve ◽  
Complete Recovery ◽  
Bell’S Palsy ◽  
Facial Canal ◽  
Chorda Tympani ◽  
Bell's Palsy ◽  
Nerve Branch ◽  
Collagen Formation ◽  
Myelin Sheaths ◽  
Metabolic Exchange

The pathogenesis of Bell's palsy is presented as retrograde epineurial compression edema with ischemia of the facial nerve. Although the etiology is unknown, an attractive theory is vasospasm, from any cause, along any facial nerve branch, with the chorda tympani, perhaps, the usual primary involvement. Retrograde vascular distension and edema, within the epineurium of the bony facial canal, compresses the nerve from outside its perineurial sheath. The compression force may be mild or severe, resulting in varying degrees of reversible or irreversible ischemic degeneration of myelin sheaths and axons, with varying degrees of cellular reaction to myelin breakdown. The edema may be resorbed, leaving reversible or irreversible nerve damage, or may stimulate collagen formation within the epineurium, with persisting fibrous compression (entrapment) neuropathy of the facial nerve. This concept is consistent with the varying results of Bell's palsy, and depends on the severity and duration of edema, and whether fibrosis occurs within the epineurium of the facial canal. Epineurial fibrosis also results in disturbance of metabolic exchange through the epineurial-permeurial-endoneurial tissues, and may ultimately result in obliteration of vascular drainage. Two temporal bone cases of Bell's palsy, one occurring ten years before death, with residual paralysis. and one two years before death, with clinical recovery, are added to the previously described four cases in the literature, three of early Bell's palsy, and one of remote palsy with almost complete recovery.

scholarly journals Unilateral Multiple Facial Nerve Branch Reconstruction Using “End-to-side Loop Graft” Supercharged by Hypoglossal Nerve

2014 ◽  
Vol 2 (10) ◽  
pp. e240 ◽  
Author(s):  
Hajime Matsumine ◽  
Ryo Sasaki ◽  
Yuichi Takeuchi ◽  
Yorikatsu Watanabe ◽  
Yosuke Niimi ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Hypoglossal Nerve ◽  
Nerve Branch

Preoperative percutaneous mapping of the frontal branch of the facial nerve to assess the risk of frontalis muscle palsy after a supraorbital keyhole approach

2013 ◽  
Vol 118 (5) ◽  
pp. 1114-1119 ◽  
Author(s):  
Jaechan Park ◽  
Tae-du Jung ◽  
Dong-Hun Kang ◽  
So-Hyun Lee
Keyword(s):  
Facial Nerve ◽  
Nerve Conduction Study ◽  
Nerve Conduction ◽  
Cerebral Aneurysms ◽  
Bimodal Distribution ◽  
Nerve Branch ◽  
Frontalis Muscle ◽  
Compound Muscle Action Potentials ◽  
Keyhole Approach ◽  
Frontal Branch

Object Although a supraorbital keyhole approach utilizing an eyebrow incision and supraorbital minicraniotomy is one of the most commonly used keyhole approaches for treating cerebral aneurysms, the risk of frontalis muscle palsy due to an injury of the frontal branch of the facial nerve remains a serious drawback to a supraorbital keyhole approach as a minimally invasive surgical technique. Therefore, the authors attempted to evaluate the risk of frontalis muscle palsy by mapping the frontal nerve branch in the lower forehead using a nerve conduction study in individual patients. Methods Percutaneous mapping of the frontal nerve branch was performed preoperatively on 52 patients who underwent supraorbital keyhole approaches for aneurysmal clipping. The maximal compound muscle action potentials (CMAPs) in the lower forehead were observed at 5 points along a laterally inclined line angled 30° from the midpupillary line, in which the points were 1.0, 1.5, 2.0, 2.5, and 3.0 cm as measured from the supraorbital margin. Results Severe frontalis muscle palsy was observed in 11 patients (21.2%), yet recovery occurred 2–5 months after surgery. No patients experienced permanent palsy. The incidence of severe palsy was 7.4% in those patients showing clear CMAPs with a high location (exclusively at 2.0, 2.5, or 3.0 cm), 14.3% in those with a bimodal distribution, 40.0% in those with a low location (exclusively at 1.5 cm), and 83.3% in those with an extremely low location (exclusively at 1.0 cm). Conclusions Percutaneous mapping of the frontal branch of the facial nerve using a nerve conduction study can be used to assess the risk of postoperative frontalis muscle palsy following a supraorbital keyhole approach. The patients with the highest risk of postoperative palsy showed a clear CMAP exclusively at 1.0 cm along the inclined line measured from the supraorbital margin.

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