-
The Journal of Neuroscience : the... Jul 2020The cholinergic neurons in the pontomesencephalic tegmentum have been shown to discharge in association with and promote cortical activation during active or attentive...
The cholinergic neurons in the pontomesencephalic tegmentum have been shown to discharge in association with and promote cortical activation during active or attentive waking and paradoxical or rapid eye movement sleep. However, GABA neurons lie intermingled with the cholinergic neurons and may contribute to or oppose this activity and role. Here we investigated and the properties, activities, and role of GABA neurons within the laterodorsal tegmental and sublaterodorsal tegmental nuclei (LDT/SubLDT) using male and female transgenic mice expressing channelrhodopsin-()- in vesicular GABA transporter ()-expressing neurons. Presumed GABA (pGABA) neurons were identified by response to photostimulation and verified by immunohistochemical staining following juxtacellular labeling pGABA neurons were found to be fast-firing neurons with the capacity to burst when depolarized from a hyperpolarized membrane potential. When stimulated in urethane-anesthetized or unanesthetized mice, the pGABA neurons fired repetitively at relatively fast rates (∼40 Hz) during a continuous light pulse or phasically in bursts (>100 Hz) when driven by rhythmic light pulses at theta (4 or 8 Hz) frequencies. pNon-GABA, which likely included cholinergic, neurons were inhibited during each light pulse to discharge rhythmically in antiphase to the pGABA neurons. The reciprocal rhythmic bursting by the pGABA and pNon-GABA neurons drove rhythmic theta activity in the EEG. Such phasic bursting by GABA neurons also occurred in WT mice in association with theta activity during attentive waking and paradoxical sleep. Neurons in the pontomesencephalic tegmentum, particularly cholinergic neurons, play an important role in cortical activation, which occurs during active or attentive waking and paradoxical or rapid eye movement sleep. Yet the cholinergic neurons lie intermingled with GABA neurons, which could play a similar or opposing role. Optogenetic stimulation and recording of these GABA neurons in mice revealed that they can discharge in rhythmic bursts at theta frequencies and drive theta activity in limbic cortex. Such phasic burst firing also occurs during natural attentive waking and paradoxical sleep in association with theta activity and could serve to enhance sensory-motor processing and memory consolidation during these states.
Topics: Anesthesia; Animals; Cerebral Cortex; Electroencephalography; Electrophysiological Phenomena; Female; Male; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Transgenic; Optogenetics; Photic Stimulation; Pons; Sleep; Vesicular Inhibitory Amino Acid Transport Proteins; Wakefulness; gamma-Aminobutyric Acid
PubMed: 32576622
DOI: 10.1523/JNEUROSCI.2875-19.2020 -
Nature Neuroscience Nov 2018Urination (also called micturition) is thought to be regulated by a neural network that is distributed in both subcortical and cortical regions. Previously,...
Urination (also called micturition) is thought to be regulated by a neural network that is distributed in both subcortical and cortical regions. Previously, urination-related neurons have been identified in subcortical structures such as the pontine micturition center (also known as Barrington's nucleus). However, the origin of the descending cortical pathway and how it interfaces with this subcortical circuit to permit voluntary initiation of urination remain elusive. Here we identified a small cluster of layer 5 neurons in the primary motor cortex whose activities tightly correlate with the onset of urination in freely behaving mice and increase dramatically during territorial marking. Optogenetically activating these neurons elicits contraction of the bladder and initiates urination, through their projections to the pontine micturition center, while silencing or ablating them impairs urination and causes retention of urine. Together these results reveal a novel cortical component upstream of the pontine micturition center that is critically involved in urination.
Topics: Animals; Mice; Motor Cortex; Neural Pathways; Neurons; Pons; Spinal Cord; Urinary Bladder; Urination
PubMed: 30361547
DOI: 10.1038/s41593-018-0256-4 -
Investigative Radiology Feb 2023In spinal cord injury (SCI), the primary mechanical injury is followed by secondary sequelae that develop over the subsequent months and manifests in biochemical,...
OBJECTIVES
In spinal cord injury (SCI), the primary mechanical injury is followed by secondary sequelae that develop over the subsequent months and manifests in biochemical, functional, and microstructural alterations, at the site of direct injury but also in the spinal cord tissue above and below the actual lesion site. Noninvasive magnetic resonance spectroscopy (MRS) can be used to assess biochemical modulation occurring in the secondary injury phase, in addition to and supporting conventional MRI, and might help predict and improve patient outcome. In this article, we aimed to examine the metabolic levels in the pons of subacute SCI by means of in vivo proton MRS at 3 T and explore the association to clinical scores.
MATERIALS AND METHODS
In this prospective study, between November 2015 and February 2018, single-voxel short-echo MRS data were acquired in healthy controls and in SCI subjects in the pons once during rehabilitation. Besides the single-point MRS examination, in addition, in participants with SCI, the clinical status (ie, motor, light touch, and pinprick scores) was assessed twice: (1) around the MRS session (approximately 10 weeks postinjury) and (2) before discharge (at approximately 9 months postinjury). The group differences were assessed with Kruskal-Wallis test, the post hoc comparison was assessed with Wilcoxon rank sum test, and the clinical correlations were conducted with Spearman rank correlation test. Bayes factor calculations completed the statistical part providing relevant evidence values.
RESULTS
Twenty healthy controls (median age, 50 years; interquartile range, 41-55 years; 18 men) and 18 subjects with traumatic SCI (median age, 50 years; interquartile range, 32-58 years; 16 men) are included. Group comparison showed an increase of total N -acetylaspartate and combined glutamate and glutamine levels in complete SCI and a reduction of total creatine in incomplete paraplegic SCI. The proton MRS-based glutathione levels at baseline correlate to the motor score improvement during rehabilitation in incomplete subacute SCI.
CONCLUSIONS
This exploratory study showed an association of the metabolite concentration of glutathione in the pons assessed at approximately 10 weeks after injury with the improvements of the motor score during the rehabilitation. Pontine glutathione levels in subjects with traumatic subacute incomplete SCI acquired remote from the injury site correlate to clinical score and might therefore be beneficial in the rehabilitation assessments.
Topics: Male; Humans; Middle Aged; Prospective Studies; Bayes Theorem; Protons; Spinal Cord Injuries; Pons
PubMed: 35926077
DOI: 10.1097/RLI.0000000000000905 -
ELife Dec 2017Coordination between the brainstem and the cortex helps to ensure that urination occurs at an appropriate time.
Coordination between the brainstem and the cortex helps to ensure that urination occurs at an appropriate time.
Topics: Brain Stem; Pons; Urinary Bladder; Urination
PubMed: 29199949
DOI: 10.7554/eLife.33219 -
Annals of Nuclear Medicine Jul 2023Standardised uptake value ratio (SUVR) is usually obtained by dividing the SUV of the region of interest (ROI) by that of the cerebellar cortex. Cerebellar cortex is not...
Comparative examination of the pons and corpus callosum as reference regions for quantitative evaluation in positron emission tomography imaging for Alzheimer's disease using C-Pittsburgh Compound-B.
OBJECTIVES
Standardised uptake value ratio (SUVR) is usually obtained by dividing the SUV of the region of interest (ROI) by that of the cerebellar cortex. Cerebellar cortex is not a valid reference in cases where amyloid β deposition or lesions are present. Only few studies have evaluated the use of other regions as references. We compared the validity of the pons and corpus callosum as reference regions for the quantitative evaluation of brain positron emission tomography (PET) using C-PiB compared to the cerebellar cortex.
METHODS
We retrospectively evaluated data from 86 subjects with or without Alzheimer's disease (AD). All subjects underwent magnetic resonance imaging, PET imaging, and cognitive function testing. For the quantitative analysis, three-dimensional ROIs were automatically placed, and SUV and SUVR were obtained. We compared these values between AD and healthy control (HC) groups.
RESULTS
SUVR data obtained using the pons and corpus callosum as reference regions strongly correlated with that using the cerebellar cortex. The sensitivity and specificity were high when either the pons or corpus callosum was used as the reference region. However, the SUV values of the corpus callosum were different between AD and HC (p < 0.01).
CONCLUSIONS
Our data suggest that the pons and corpus callosum might be valid reference regions.
Topics: Humans; Alzheimer Disease; Amyloid beta-Peptides; Corpus Callosum; Retrospective Studies; Positron-Emission Tomography; Brain; Pons; Aniline Compounds
PubMed: 37160863
DOI: 10.1007/s12149-023-01843-y -
Brain Structure & Function Sep 2015Current cellular-based connectomics approaches aim to delineate the functional or structural organizations of mammalian brain circuits through neuronal activity mapping...
Current cellular-based connectomics approaches aim to delineate the functional or structural organizations of mammalian brain circuits through neuronal activity mapping and/or axonal tracing. To discern possible connectivity between functionally identified neurons in widely distributed brain circuits, reliable and efficient network-based approaches of cross-registering or cross-correlating such functional-structural data are essential. Here, a novel cross-correlation approach that exploits multiple timing-specific, response-specific, and cell-specific neuronal characteristics as coincident fingerprint markers at the systems, network, and cellular levels is proposed. Application of this multiscale temporal-cellular coincident fingerprinting assay to the respiratory central pattern generator network in rats revealed a descending excitatory pathway with characteristic activity pattern and projecting from a distinct neuronal population in pons to its counterparts in medulla that control the post-inspiratory phase of the respiratory rhythm important for normal breathing, airway protection, and respiratory-vocalization coordination. This enabling neurotracing approach may prove valuable for functional connectivity mapping of other brain circuits.
Topics: Action Potentials; Animals; Medulla Oblongata; Nerve Net; Neural Pathways; Neurons; Pons; Rats
PubMed: 25056933
DOI: 10.1007/s00429-014-0838-1 -
The International Journal of... Aug 2018Eight-and-a-half syndrome is caused by a lesion in the dorsal tegmentum of the caudal pons involving parapontine reticular formation and median longitudinal fasciculus,... (Review)
Review
BACKGROUND
Eight-and-a-half syndrome is caused by a lesion in the dorsal tegmentum of the caudal pons involving parapontine reticular formation and median longitudinal fasciculus, as well as the nucleus and/or the fasciculus of the facial nerve. It is characterized by one-and-a-half syndrome and an ipsilateral cranial nerve VII palsy. Also, many variants of eight-and-a-half syndrome have been described, including nine syndrome, thirteen-and-a-half syndrome and fifteen-and-a-half syndrome.
METHODS
We describe a case of a 49-year-old man who presented with eight-and-a-half syndrome combined with contralateral hemiparesis. We reviewed the literature describing the related spectrum of eight-and-a-half syndrome associated with various etiologies.
RESULTS
Brain computed tomography scan revealed a hyperdensity located in the left paramedian aspect of the dorsal pons. T2-weighted magnetic resonance imaging at the 11-month follow-up showed hyperintensity and enlargement of the inferior olivary nuclei, which were compatible with a diagnosis of hypertrophic olivary degeneration. In light of our observations and cases reported in the literature, we categorize the spectrum of eight-and-a-half syndrome into three types, namely classic eight-and-a-half syndrome, eight-and-a-half syndrome variants and eight-and-a-half plus syndrome. Besides, the clinical feature and outcome of the three types are discussed in this article.
CONCLUSIONS
Recognition of the spectrum of eight-and-a-half syndrome allows precise anatomic localization of the lesion to pontine tegmentum region.
Topics: Functional Laterality; Humans; Intracranial Hemorrhages; Magnetic Resonance Imaging; Male; Middle Aged; Paresis; Perceptual Disorders; Pons; Tomography, X-Ray Computed; Vision Disorders
PubMed: 29243534
DOI: 10.1080/00207454.2017.1418344 -
Neuron Apr 2019Recent research has identified a single factor accounting for broad risk to experience common forms of psychopathology. Structural alterations of cerebellar circuitry... (Review)
Review
Recent research has identified a single factor accounting for broad risk to experience common forms of psychopathology. Structural alterations of cerebellar circuitry have emerged as a neural nexus of this broad risk, highlighting the cerebellum's importance for executive control.
Topics: Anisotropy; Cerebellum; Disease Susceptibility; Functional Neuroimaging; Gray Matter; Humans; Magnetic Resonance Imaging; Mental Disorders; Neural Pathways; Organ Size; Pons; Prefrontal Cortex; Psychopathology; Risk; Thalamus; White Matter
PubMed: 30946819
DOI: 10.1016/j.neuron.2019.02.031 -
NeuroImage Jun 2015In this paper we present a method to segment four brainstem structures (midbrain, pons, medulla oblongata and superior cerebellar peduncle) from 3D brain MRI scans. The...
In this paper we present a method to segment four brainstem structures (midbrain, pons, medulla oblongata and superior cerebellar peduncle) from 3D brain MRI scans. The segmentation method relies on a probabilistic atlas of the brainstem and its neighboring brain structures. To build the atlas, we combined a dataset of 39 scans with already existing manual delineations of the whole brainstem and a dataset of 10 scans in which the brainstem structures were manually labeled with a protocol that was specifically designed for this study. The resulting atlas can be used in a Bayesian framework to segment the brainstem structures in novel scans. Thanks to the generative nature of the scheme, the segmentation method is robust to changes in MRI contrast or acquisition hardware. Using cross validation, we show that the algorithm can segment the structures in previously unseen T1 and FLAIR scans with great accuracy (mean error under 1mm) and robustness (no failures in 383 scans including 168 AD cases). We also indirectly evaluate the algorithm with a experiment in which we study the atrophy of the brainstem in aging. The results show that, when used simultaneously, the volumes of the midbrain, pons and medulla are significantly more predictive of age than the volume of the entire brainstem, estimated as their sum. The results also demonstrate that the method can detect atrophy patterns in the brainstem structures that have been previously described in the literature. Finally, we demonstrate that the proposed algorithm is able to detect differential effects of AD on the brainstem structures. The method will be implemented as part of the popular neuroimaging package FreeSurfer.
Topics: Aged; Aging; Algorithms; Atlases as Topic; Atrophy; Bayes Theorem; Brain Stem; Datasets as Topic; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Mesencephalon; Middle Aged; Models, Statistical; Pons; Reproducibility of Results
PubMed: 25776214
DOI: 10.1016/j.neuroimage.2015.02.065 -
Respiratory Physiology & Neurobiology May 2024Breathing is the only vital function that can be volitionally controlled. However, a detailed understanding how volitional (cortical) motor commands can transform vital... (Review)
Review
Breathing is the only vital function that can be volitionally controlled. However, a detailed understanding how volitional (cortical) motor commands can transform vital breathing activity into adaptive breathing patterns that accommodate orofacial behaviors such as swallowing, vocalization or sniffing remains to be developed. Recent neuroanatomical tract tracing studies have identified patterns and origins of descending forebrain projections that target brain nuclei involved in laryngeal adductor function which is critically involved in orofacial behavior. These nuclei include the midbrain periaqueductal gray and nuclei of the respiratory rhythm and pattern generating network in the brainstem, specifically including the pontine Kölliker-Fuse nucleus and the pre-Bötzinger complex in the medulla oblongata. This review discusses the functional implications of the forebrain-brainstem anatomical connectivity that could underlie the volitional control and coordination of orofacial behaviors with breathing.
Topics: Brain Stem; Medulla Oblongata; Respiration; Pons; Kolliker-Fuse Nucleus; Neural Pathways
PubMed: 38295924
DOI: 10.1016/j.resp.2024.104227