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Journal of Child Neurology Feb 2022To evaluate the role of diffusion tensor imaging of the auditory pathway in patients with Crigler Najjar syndrome type I and its relation to auditory brainstem response.
AIM
To evaluate the role of diffusion tensor imaging of the auditory pathway in patients with Crigler Najjar syndrome type I and its relation to auditory brainstem response.
METHODS
Prospective study was done including 12 patients with Crigler Najjar syndrome type I and 10 age- and sex-matched controls that underwent diffusion tensor imaging of brain. Mean diffusivity and fractional anisotropy at 4 regions of the brain and brainstem on each side were measured and correlated with the results of auditory brainstem response for patients.
RESULTS
There was significantly higher mean diffusivity of cochlear nucleus, superior olivary nucleus, inferior colliculus, and auditory cortex of patients versus controls on both sides for all regions ( = .001). The fractional anisotropy of cochlear nucleus, superior olivary nucleus, inferior colliculus, and auditory cortex of patients versus controls was significantly lower, with values of, respectively, .001, .001, .003, and .001 on the right side and .001, .001, .003, and .001 on left side, respectively. Also, a negative correlation was found between the maximum bilirubin level and fractional anisotropy of the left superior olivary nucleus and inferior colliculus of both sides. A positive correlation was found between the mean diffusivity and auditory brainstem response wave latency of the right inferior colliculus and left cochlear nucleus. The fractional anisotropy and auditory brainstem response wave latency of the right superior olivary nucleus, left cochlear nucleus, and inferior colliculus of both sides were negatively correlated.
CONCLUSION
Diffusion tensor imaging can detect microstructural changes in the auditory pathway in Crigler Najjar syndrome type I that can be correlated with auditory brainstem response.
Topics: Adult; Auditory Pathways; Crigler-Najjar Syndrome; Diffusion Tensor Imaging; Evoked Potentials, Auditory, Brain Stem; Female; Humans; Male; Middle Aged; Prospective Studies
PubMed: 34961382
DOI: 10.1177/08830738211025865 -
The Journal of Comparative Neurology Sep 2018In addition to its well-known role in pattern vision, light influences a wide range of non-image forming, subconscious visual behaviors including circadian...
In addition to its well-known role in pattern vision, light influences a wide range of non-image forming, subconscious visual behaviors including circadian photoentrainment, sleep, mood, learning, and the pupillary light reflex. Each of these behaviors is thought to require input from the M1 subtype of melanopsin-expressing, intrinsically photosensitive retinal ganglion cell (ipRGC). Recent work has demonstrated that the M1 subtype of ipRGC can be further subdivided based on expression of the transcription factor Brn3b. Brn3b-positive M1 ipRGCs project to the olivary pretectal nucleus and are necessary for the pupillary light reflex, while Brn3b-negative M1 ipRGCs project to the suprachiasmatic nucleus (SCN) and are sufficient for circadian photoentrainment. However, beyond the circadian and pupil systems, little is known about the projection patterns of M1 ipRGC subtypes. Here we show that Brn3b-positive M1 ipRGCs comprise the majority of sparse M1 ipRGC inputs to the thalamus, midbrain, and hypothalamus. Our data demonstrate that very few brain targets receive convergent input from both M1 ipRGC subpopulations, suggesting that each subpopulation drives a specific subset of light-driven behaviors.
Topics: Animals; Circadian Rhythm; Female; Homeodomain Proteins; Male; Mice; Mice, Inbred C57BL; Olivary Nucleus; Reflex, Pupillary; Retinal Ganglion Cells; Rod Opsins; Suprachiasmatic Nucleus; Transcription Factor Brn-3B; Visual Pathways
PubMed: 29888785
DOI: 10.1002/cne.24469 -
Frontiers in Neurology 2021The abnormal T1-weighted imaging of MRI can be used to characterize neonatal acute bilirubin encephalopathy (ABE) in newborns, but has limited use in evaluating the...
The abnormal T1-weighted imaging of MRI can be used to characterize neonatal acute bilirubin encephalopathy (ABE) in newborns, but has limited use in evaluating the severity and prognosis of ABE. This study aims to assess the value of diffusion kurtosis imaging (DKI) in detecting ABE and understanding its pathogenesis. Seventy-six newborns with hyperbilirubinemia were grouped into three groups (mild group, moderate group, and severe group) based on serum bilirubin levels. All the patients underwent conventional MRI and DKI serial, as well as 40 healthy full-term infants (control group). The regions of interest (ROIs) were the bilateral globus pallidus, dorsal thalamus, frontal lobe, auditory radiation, superior temporal gyrus, substantia nigra, hippocampus, putamen, and inferior olivary nucleus. The values of mean diffusivity (MD), axial kurtosis (AK), radial kurtosis (RK), and mean kurtosis (MK), and fractional anisotropy (FA), radial diffusivity (RD), and axis diffusivity (AD) of the ROIs were evaluated. All newborns were followed up and evaluated using the Denver Development Screening Test (DDST). According to the follow-up results, the patients were divided into the normal group, the suspicious abnormal group, and the abnormal group. Compared with the control group, significant differences were observed with the increased MK of dorsal thalamus, AD of globus pallidus in the moderate group, and increased RD, MK, AK, and RK value of globus pallidus, dorsal thalamus, auditory radiation, superior temporal gyrus, and hippocampus in the severe group. The peak value of total serum bilirubin was moderately correlated with the MK of globus pallidus, dorsal thalamus, and auditory radiation and was positively correlated with the other kurtosis value. Out of 76 patients, 40 finished the DDST, and only 9 patients showed an abnormality. Compared with the normal group, the AK value of inferior olivary nucleus showed significant differences ( < 0.05) in the suspicious abnormal group, and the MK of globus pallidus, temporal gyrus, and auditory radiation; RK of globus pallidus, dorsal thalamus, and auditory radiation; and MD of globus pallidus showed significant differences ( < 0.05) in the abnormal group. DKI can reflect the subtle structural changes of neonatal ABE, and MK is a sensitive indicator to indicate the severity of brain damage.
PubMed: 34512498
DOI: 10.3389/fneur.2021.645534 -
PloS One 2018The presence of 'giant' synapses in the auditory brainstem is thought to be a specialization designed to encode temporal information to support perception of pitch,...
The presence of 'giant' synapses in the auditory brainstem is thought to be a specialization designed to encode temporal information to support perception of pitch, frequency, and sound-source localisation. These 'giant' synapses have been found in the ventral cochlear nucleus, the medial nucleus of the trapezoid body and the ventral nucleus of the lateral lemniscus. An interpretation of these synapses as simple relays has, however, been challenged by the observation in the gerbil that the action potential frequently fails in the ventral cochlear nucleus. Given the prominence of these synapses it is important to establish whether this phenomenon is unique to the gerbil or can be observed in other species. Here we examine the responses of units, thought to be the output of neurons in receipt of 'giant' synaptic endings, in the ventral cochlear nucleus and the medial nucleus of the trapezoid body in the guinea pig. We found that failure of the action-potential component, recorded from cells in the ventral cochlear nucleus, occurred in ~60% of spike waveforms when recording spontaneous activity. In the medial nucleus of the trapezoid body, we did not find evidence for action-potential failure. In the ventral cochlear nucleus action-potential failures transform the receptive field between input and output of bushy cells. Additionally, the action-potential failures result in "non-primary-like" temporal-adaptation patterns. This is important for computational models of the auditory system, which commonly assume the responses of ventral cochlear nucleus bushy cells are very similar to their "primary like" auditory-nerve-fibre inputs.
Topics: Action Potentials; Animals; Auditory Pathways; Brain Stem; Cochlear Nerve; Cochlear Nucleus; Guinea Pigs; Nerve Fibers; Neurons; Olivary Nucleus; Sound Localization; Synapses; Synaptic Transmission; Trapezoid Body
PubMed: 30286113
DOI: 10.1371/journal.pone.0203712 -
Radiologia 2015To review the pathophysiologic mechanisms involved in hypertrophic olivary degeneration, with attention to epidemiologic and clinical aspects and especially to imaging...
OBJECTIVE
To review the pathophysiologic mechanisms involved in hypertrophic olivary degeneration, with attention to epidemiologic and clinical aspects and especially to imaging findings.
MATERIAL AND METHODS
We reviewed 5 patients diagnosed with hypertrophic olivary degeneration at our center from 2010 through 2013, analyzing relevant clinical, epidemiologic, and radiologic findings.
RESULTS
In all cases, a hyperintensity was seen in the inferior olivary nuclei in FLAIR and T2-weighted sequences. No signal alterations were seen on T1-weighted sequences, and no enhancement was seen after intravenous injection of contrast material. In the cases studied by diffusion-weighted imaging, no significant alterations were seen in these sequences. Olivary hypertrophy was seen in all patients except in one, in whom presumably not enough time had elapsed for hypertrophy to occur. The alterations were bilateral in two of the five cases. Only one case exhibited the typical clinical manifestations.
CONCLUSION
Given that patients may not present clinical manifestations that can be attributed to hypertrophic olivary degeneration, it is important to recognize the characteristic radiologic signs of this entity.
Topics: Humans; Hypertrophy; Magnetic Resonance Imaging; Olivary Nucleus
PubMed: 25660593
DOI: 10.1016/j.rx.2014.12.008 -
Expert Review of Neurotherapeutics Feb 2018There are few medications that are available for the treatment of essential tremor (ET) and they are only moderately effective. Areas covered: Data were obtained from a... (Review)
Review
There are few medications that are available for the treatment of essential tremor (ET) and they are only moderately effective. Areas covered: Data were obtained from a PubMed search. Original articles, review articles, and clinical guidelines were included. Two disease models for ET have been proposed: 1) the olivary model, which attributes ET to a pathological pacemaker in the inferior olivary nucleus, and 2) the cerebellar degeneration model, which postulates that ET originates in the cerebellum and could be related to deficient or abnormal Purkinje cell (PC) output. Underlying biochemical dysfunction in T-type calcium channels (T-tCaC) may loosely be linked to the first model and deficiency/abnormality in γ-aminobutyric acid (GABA) neurotransmission, to the second. Expert commentary: Human data points robustly to the role of GABA in ET. Numerous medications that target the GABA system have been tried, with variable success. Given the many different types of GABA-ergic neurons, and the multitude of GABA receptor subtypes, a given medication could have competing/cancelling effects. It would seem that influencing GABA receptors broadly is not as effective as targeting certain GABA receptor subtypes. Future research should seek to identify molecular candidates that have a more targeted effect within the GABA system.
Topics: Animals; Brain; Calcium Channels, T-Type; Cerebellum; Essential Tremor; Humans; Neurons; Olivary Nucleus; Purkinje Cells; Receptors, GABA; Receptors, GABA-A; Synaptic Transmission
PubMed: 29206482
DOI: 10.1080/14737175.2018.1413353 -
Journal of Chemical Neuroanatomy Jul 2023The distribution of the synaptic vesicle protein synaptoporin was investigated by immunofluorescence in the central auditory system of the mouse brainstem. Synaptoporin...
The distribution of the synaptic vesicle protein synaptoporin was investigated by immunofluorescence in the central auditory system of the mouse brainstem. Synaptoporin immunostaining displayed region-specific differences. High and moderate accumulations of were seen in the superficial layer of the dorsal cochlear nucleus, dorsal and external regions of the inferior colliculus, the medial and dorsal divisions of the medial geniculate body and in periolivary regions of the superior olivary complex (SOC). Low or absent labeling was observed in the more central parts of these structures such as the principal nuclei of the SOC. It was conspicuous that dense synaptoporin immunoreactivity was detected predominantly in areas, which are known to be synaptic fields of multimodal, extra-auditory inputs. Target neurons of synaptoporin-positive synapses in the SOC were then identified by double-labelling immunofluorescence microscopy. We thereby detected synaptoporin puncta perisomatically at nitrergic, glutamatergic and serotonergic neurons but none next to neurons immunoreactive for choline-acetyltransferase and calcitonin-gene related peptide. These results leave open whether functionally distinct neuronal groups are accessed in the SOC by synaptoporin-containing neurons. The last part of our study sought to find out whether synaptoporin-positive neurons originate in the medial paralemniscal nucleus (MPL), which is characterized by expression of the peptide parathyroid hormone 2 (PTH2). Anterograde neuronal tracing upon injection into the MPL in combination with synaptoporin- and PTH2-immunodetection showed that (1) the MPL projects to the periolivary SOC using PTH2 as transmitter, (2) synaptoporin-positive neurons do not originate in the MPL, and (3) the close juxtaposition of synaptoporin-staining with either the anterograde tracer or PTH2 reflect concerted action of the different inputs to the SOC.
Topics: Mice; Animals; Olivary Nucleus; Brain Stem; Inferior Colliculi; Neurons; Parathyroid Hormone; Auditory Pathways
PubMed: 36958466
DOI: 10.1016/j.jchemneu.2023.102259 -
The Journal of Neuroscience : the... Oct 2018We identify as an exclusive marker of inhibitory projection neurons in the lateral and interposed, but not the medial, cerebellar nuclei. neurons make up ∼80% of...
We identify as an exclusive marker of inhibitory projection neurons in the lateral and interposed, but not the medial, cerebellar nuclei. neurons make up ∼80% of neurons in these nuclei and are indistinguishable by soma size from other inhibitory neurons. All neurons of the lateral and interposed cerebellar nuclei are generated at approximately E10/10.5 and extend long-range, predominantly contralateral projections to the inferior olive. A small population in the adjacent vestibular nucleus "Y" sends an ipsilateral projection to the oculomotor nucleus. Cerebellar and glutamatergic projection neurons assemble in non-overlapping populations at the nuclear transition zone, and their integration into a coherent nucleus depends on function. Targeted ablation of cells by conditional viral expression of diphtheria toxin leads to significantly impaired motor learning. Contrary to expectations, associative learning is unaffected by unilateral neuron elimination in the interposed and lateral nuclei. The cerebellar nuclei are central to cerebellar function, yet how they modulate and process cerebellar inputs and outputs is still primarily unknown. Our study gives a direct insight into how nucleo-olivary projection neurons are generated, their projections, and their function in an intact behaving mouse. These neurons play a critical conceptual role in all models of cerebellar function, and this study represents the first specific analysis of their molecular identity and function and offers a powerful model for future investigation of cerebellar function in motor control and learning.
Topics: Animals; Association Learning; Cells, Cultured; Cerebellar Nuclei; Cerebellum; Female; Locomotion; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neural Pathways; Olivary Nucleus; SOXB2 Transcription Factors
PubMed: 30242051
DOI: 10.1523/JNEUROSCI.1456-18.2018 -
Journal of Neurology, Neurosurgery, and... Jul 2021
Topics: Adult; Brain Stem; Encephalitis; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Nerve Degeneration; Olivary Nucleus
PubMed: 33452052
DOI: 10.1136/jnnp-2020-325569 -
Annals of Indian Academy of Neurology 2020The structural imaging of brain does not demonstrate any changes in the vast majority of patients with vitamin B12 deficiency, even in the advanced stages.
CONTEXT
The structural imaging of brain does not demonstrate any changes in the vast majority of patients with vitamin B12 deficiency, even in the advanced stages.
AIMS
We investigated the microstructural changes in the brain with diffusion imaging among patients with biochemical evidence of B12 deficiency.
PATIENTS AND METHODS
We retrospectively analyzed all diffusion-weighted MRI images between the periods 2014-2016 who had biochemical evidence of B12. The age-sex matched controls were chosen from the group with normal B12 levels. Patients with pathological findings in conventional MRI images were excluded from the study.
RESULTS
About 37 patients were recruited (22 women, 15 men; mean age, 34.1 ± 9.9 years; age range). They were about thirty-four age-and sex-matched controls (with normal B12 levels), which were also included in the study. The mean apparent diffusion coefficient (ADC) value of amygdala (773.8 ± 49.9 vs. 742.2 ± 24.2, = 0.01), hypothalamus (721.3 ± 39.2 vs. 700.2 ± 38.2, = 0.02), striate cortex (737.6 ± 77.6 vs. 704.3 ± 58.2, = 0.04), suprafrontal gyrus (740.7 ± 46.9 vs. 711.6 ± 40.7, = 0.007) and medulla oblongata-olivary nucleus (787.3 ± 56.4 vs. 759.7 ± 46.2, = 0.02) were significantly higher in B12 deficiency group compared to controls, whereas ADC values were similar at hippocampus, thalamus, insula, corpus striatum, cingulate gyrus, occipital gyrus, dentate nucleus, cerebral pedicle, tegmentum, pons, and posterior medulla oblongata.
CONCLUSIONS
Our study indicates that a significant increase in ADC values occurs in multiple brain regions in patients with vitamin B12.
PubMed: 32055125
DOI: 10.4103/aian.AIAN_485_18