scholarly journals Hypertrophy of the Anterior External Arcuate Fasciculus: A Rare Variant With Implications for the Development of the Arcuate Nucleus

2020 ◽  
Vol 14 ◽  
Author(s):  
Renee Stonebridge ◽  
Ross J. Taliano ◽  
Terra D. Velilla ◽  
Douglas C. Anthony
Keyword(s):  
Arcuate Nucleus ◽  
Inferior Olivary Nucleus ◽  
Arcuate Fasciculus ◽  
Normal Range ◽  
Ventral Medullary Surface ◽  
Neuronal Distribution ◽  
Rare Anatomic Variant ◽  
Inferior Olivary ◽  
Olivary Nucleus ◽  
Potential Origin

A rare anatomic variant of a markedly enlarged anterior external arcuate fasciculus (AEAF) on the ventral medullary surface is reported and compared to two controls. The hypertrophic AEAF was nine times larger in diameter than normal, whereas the arcuate nucleus (AN) and inferior olivary nucleus (ION) appeared histologically normal in size and neuronal distribution, and morphometric analysis of the AN confirmed that it was within the normal range. Calbindin-2 (calretinin, CALB2) expression was identified in the AN and in the fibers of the normal AEAF. The hypertrophic AEAF did not contain calbindin-2–expressing fibers. CALB2 expression was also present in the ventrolateral portion of the ION, both in the index case and in one of the control cases. The origin of the additional fibers was not identified; however, the potential origin of these fibers and its implications for the development of the AEAF are discussed.

Drug-induced activation of the inferior olivary nucleus in young rabbits

1985 ◽  
Vol 24 (7) ◽  
pp. 645-654 ◽  
Author(s):  
L.A. Barragan ◽  
N. Delhaye-Bouchaud ◽  
P. Laget
Keyword(s):  
Inferior Olivary Nucleus ◽  
Drug Induced ◽  
Inferior Olivary ◽  
Olivary Nucleus

scholarly journals Inferior Olivary nucleus degeneration does not lessen tremor in essential tremor

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Elan D. Louis ◽  
Daniel Trujillo Diaz ◽  
Sheng-Han Kuo ◽  
Shi-Rui Gan ◽  
Etty P. Cortes ◽  
...  
Keyword(s):  
Essential Tremor ◽  
Inferior Olivary Nucleus ◽  
Inferior Olivary ◽  
Olivary Nucleus

Hyperventilation evoked by activation of the vicinity of the caudal inferior olivary nucleus depends on the fastigial nucleus in anesthetized rats

2008 ◽  
Vol 104 (5) ◽  
pp. 1351-1358 ◽  
Author(s):  
Jianguo Zhuang ◽  
Fadi Xu ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Chemical Activation ◽  
Ibotenic Acid ◽  
Fastigial Nucleus ◽  
Inferior Olivary Nucleus ◽  
Ventilatory Responses ◽  
Respiratory Modulation ◽  
Spontaneously Breathing ◽  
Inferior Olivary ◽  
Olivary Nucleus

Several studies have demonstrated that cerebellar deep nuclei, particularly the rostral fastigial nucleus (FNr), are involved in respiratory modulation. These nuclei receive inputs from the contralateral caudal inferior olivary nuclei of the medulla. The objectives of this study were to determine whether electrical and chemical activation of the vicinity of the caudal inferior olivary nuclei (vIOc) affected respiration and, if true, whether the FNr was involved in the vIOc stimulation-evoked ventilatory responses. Experiments were conducted in 30 anesthetized and spontaneously breathing rats. Our results showed that 1) electrical (25 or 100 μA at 10 or 20 Hz for 10 s) and chemical (1 or 100 mM, 25–50 nl N-methyl-d-aspartate) stimulation of the vIOc augmented ventilation predominantly via increasing tidal volume; 2) the responses to the electrical stimulation were almost eliminated by lesion of the contralateral FNr via microinjection of ibotenic acid; and 3) the respiratory responses to electrical stimulation in the vicinity of the rostral IO were 65–70% smaller compared with that evoked by vIOc stimulation. These findings strongly suggest that vIOc neurons play a significant role in modulation of respiratory activity, largely depending on their projections to the FNr.

Subthreshold oscillations of the membrane potential: a functional synchronizing and timing device

1993 ◽  
Vol 70 (5) ◽  
pp. 2181-2186 ◽  
Author(s):  
I. Lampl ◽  
Y. Yarom
Keyword(s):  
Membrane Potential ◽  
Logic Gate ◽  
Maximum Amplitude ◽  
Sine Wave ◽  
Inferior Olivary Nucleus ◽  
Synaptic Potential ◽  
Synaptic Potentials ◽  
Subthreshold Oscillations ◽  
Inferior Olivary ◽  
Olivary Nucleus

1. Subthreshold membrane potential oscillations have been observed in different types of CNS neurons. In this in vitro study, we examined the possible role of these oscillations by analyzing the responses of neurons from the inferior olivary nucleus to a combined stimulation of sine wave and synaptic potentials. 2. A nonlinear summation of the sine wave and the synaptic potential occurred in olivary neurons; a superlinear summation occurred when the synaptic potential was elicited at the trough of the sine wave or during the rising phase. On the other hand, a less than linear summation occurred when the synaptic potentials were evoked during the falling phase of the wave. 3. Significant changes in the delay of the synaptic responses were observed. As a result of these changes, the maximum amplitude of the response occurred at the peak of the sine wave, regardless of the exact time of stimulation. The output of the neuron was therefore synchronized with the sine wave and depended only partly on the input phase. 4. These data demonstrate that neurons from the inferior olivary nucleus are capable of operating as accurate synchronizing devices. Moreover, by affecting the delay line, they act as a logic gate that ensures that the information will be added to the system only at given times.

scholarly journals Neuro-Behçet: Pons Involvement with Longitudinal Extension to Midbrain and Hypertrophic Olivary Degeneration

2015 ◽  
Vol 7 (2) ◽  
pp. 148-151 ◽  
Author(s):  
Emilio Franco-Macías ◽  
Florinda Roldán-Lora ◽  
Paula Martínez-Agregado ◽  
Nuria Cerdá-Fuertes ◽  
Francisco Moniche
Keyword(s):  
Brain Mri ◽  
Inferior Olivary Nucleus ◽  
Intravenous Methylprednisolone ◽  
Hypertrophic Olivary Degeneration ◽  
Oral Ulcers ◽  
Pyramidal Syndrome ◽  
Extensive Lesion ◽  
Longitudinal Extension ◽  
Inferior Olivary ◽  
Olivary Nucleus

A 21-year-old right-handed man developed progressive dysarthria and gait disturbance over 4 months (associated with intermittent hiccups). During that time, he also suffered from uveitis. A physical examination showed pseudobulbar and pyramidal signs and genital and oral ulcers. A brain MRI revealed an extensive lesion mainly located in the ventral pons, with an extension upwards to the midbrain. The inferior olivary nucleus also showed hyperintensity. After the treatment with intravenous methylprednisolone and pulses of cyclophosphamide, he improved. As observed on his MRI, his lesions also improved, except for an increase of the inferior olivary nucleus, consistent with hypertrophic olivary degeneration. Neuro-Behçet tropism for ventral brainstem explains the usual presentation with pyramidal syndrome. Hypertrophic olivary degeneration due to pons involvement could explain the hiccup attacks in a few known cases.

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