scholarly journals Optogenetic Interrogation of Circuits Following Neurotrauma

2021 ◽  
Vol 14 ◽  
Author(s):  
Steven Ceto ◽  
Grégoire Courtine

Biological and engineering strategies for neural repair and recovery from neurotrauma continue to emerge at a rapid pace. Until recently, studies of the impact of neurotrauma and repair strategies on the reorganization of the central nervous system have focused on broadly defined circuits and pathways. Optogenetic modulation and recording methods now enable the interrogation of precisely defined neuronal populations in the brain and spinal cord, allowing unprecedented precision in electrophysiological and behavioral experiments. This mini-review summarizes the spectrum of light-based tools that are currently available to probe the properties and functions of well-defined neuronal subpopulations in the context of neurotrauma. In particular, we highlight the challenges to implement these tools in damaged and reorganizing tissues, and we discuss best practices to overcome these obstacles.

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Song Cao ◽  
Daniel W. Fisher ◽  
Guadalupe Rodriguez ◽  
Tian Yu ◽  
Hongxin Dong

Abstract Background The role of microglia in Alzheimer’s disease (AD) pathogenesis is becoming increasingly important, as activation of these cell types likely contributes to both pathological and protective processes associated with all phases of the disease. During early AD pathogenesis, one of the first areas of degeneration is the locus coeruleus (LC), which provides broad innervation of the central nervous system and facilitates norepinephrine (NE) transmission. Though the LC-NE is likely to influence microglial dynamics, it is unclear how these systems change with AD compared to otherwise healthy aging. Methods In this study, we evaluated the dynamic changes of neuroinflammation and neurodegeneration in the LC-NE system in the brain and spinal cord of APP/PS1 mice and aged WT mice using immunofluorescence and ELISA. Results Our results demonstrated increased expression of inflammatory cytokines and microglial activation observed in the cortex, hippocampus, and spinal cord of APP/PS1 compared to WT mice. LC-NE neuron and fiber loss as well as reduced norepinephrine transporter (NET) expression was more evident in APP/PS1 mice, although NE levels were similar between 12-month-old APP/PS1 and WT mice. Notably, the degree of microglial activation, LC-NE nerve fiber loss, and NET reduction in the brain and spinal cord were more severe in 12-month-old APP/PS1 compared to 12- and 24-month-old WT mice. Conclusion These results suggest that elevated neuroinflammation and microglial activation in the brain and spinal cord of APP/PS1 mice correlate with significant degeneration of the LC-NE system.


1930 ◽  
Vol 51 (6) ◽  
pp. 889-902 ◽  
Author(s):  
Jules Freund

1. Antibodies can be extracted from the brain and spinal cord of rabbits actively or passively immunized with typhoid bacilli. 2. The titers of the antibodies in the extracts of brain and cord depend upon the titer of the blood serum. In actively immunized rabbits the following numerical relationships exist between the titers of the serum and of these organ extracts: The ratio of the titer of the serum is to the titers of extract of brain and of the spinal cord about as 100 is to 0.8; the titer of the serum is to the titer of the cerebrospinal fluid as 100 is to 0.3. In passively immunized rabbits the titer of the serum is to the titer of brain and spinal-cord extract as 100 is to 0.7. 3. The antibodies recovered from the brain are not due to the presence of blood in it for perfusion of the brain does not reduce its antibody content appreciably. 4. Antibodies penetrate into the spinal fluid from the blood even in the absence of inflammation of the meninges. When the penetration is completed the following numerical relationship exists between the titer of the serum and that of the cerebrospinal fluid: 100 to 0.25. 5. The penetration into the cerebrospinal fluid of antibodies injected intravenously proceeds at a slow rate, being completed only several hours after the immune serum has been injected. The penetration of antibodies into the tissue of the brain occurs at a very rapid rate. It is completed within 15 minutes. 6. It is very unlikely that when the immune serum is injected intravenously the antibodies reach the brain tissue by way of the cerebrospinal fluid, for (1) the antibody titer of the cerebrospinal fluid is lower than that of the brain extract, and (2) antibodies penetrate faster into the tissue of the brain than into the cerebrospinal fluid.


2015 ◽  
Vol 23 (3) ◽  
pp. 290-293 ◽  
Author(s):  
Ian Peeters ◽  
Jan W. Casselman ◽  
Stefaan J. Vandecasteele ◽  
Alexander Janssen ◽  
Bart Regaert ◽  
...  

Nocardiosis of the central nervous system is a challenging and difficult diagnosis for the clinician. The combination of infections of the brain and spinal cord is even more rare. The authors report on a patient with multiple lesions in the brainstem and cervical spinal cord. This 81-year-old immunocompetent woman presented with symptoms of progressive walking difficulty and ataxia. The results of an extensive workup with laboratory investigation, MRI, lumbar puncture, positron emission tomography (PET), and bone marrow biopsy remained inconclusive. Only after an open biopsy of a cervical lesion by an anterior approach through a partial central corpectomy of the cervical spine, was the diagnosis of nocardiosis made, allowing for specific antibiotic treatment.


1908 ◽  
Vol 54 (225) ◽  
pp. 146-148
Author(s):  
William W. Ireland

Rothmann points out how important it is to surgeons that the localisation of lesions in the brain and spinal cord should be made with the utmost accuracy. In many cases diseases do not strike suddenly upon a nervous system previously intact. Often the circulation has been previously deranged by arterial sclerosis, which prepares the way for transitory hemiplegia or aphasia. Sometimes there is loss of function after central lesions, which disappears in longer or shorter time. Goltz and his followers have treated many effects following the extirpation of the whole or part of the cerebrum as due to what they call inhibition (Hemmung). Thus the functions of the spinal cord are much impaired after removal of the cerebral ganglia, or the lower portion of the cord loses its reflex function after section higher up, but after a while it again resumes its act$ibon.


2020 ◽  
pp. 5785-5802
Author(s):  
Christian Krarup

This chapter looks at electrophysiological studies of the central nervous system and peripheral nervous system—the core investigations in clinical neurophysiology. These include electroencephalography, which is of value to diagnose epilepsy caused by focal or diffuse brain diseases, electromyography and nerve conduction studies, which are of value to diagnose diseases in nerves and muscles, and evoked potentials, which are of value to diagnose diseases of white matter in the brain and spinal cord.


2016 ◽  
Vol 25 (2) ◽  
pp. 158-162 ◽  
Author(s):  
José Ledamir Sindeaux Neto ◽  
Michele Velasco ◽  
José Mauro Vianna da Silva ◽  
Patricia de Fátima Saco dos Santos ◽  
Osimar Sanches ◽  
...  

Abstract The genus Myxobolus, parasites that infect fishes, which cause myxobolosis, includes spore organisms belonging to the phylum Myxozoa and represents approximately 36% of all species described for the entire phylum. This study describes lymphocytic meningoencephalomyelitis associated with Myxobolus sp. infection in the brain and spinal cord (the central nervous system, CNS) of Eigenmannia sp., from the Amazon estuary region, in the Administrative District of Outeiro (DAOUT), Belém, Pará, Brazil. In May and June 2015, 40 Eigenmannia sp. specimens were captured from this region and examined. The fish were anesthetized, slaughtered and dissected for sexing (gonad evaluation) and studying parasites and cysts; after diagnosing the presence of the myxozoans using a light microscope, small fragments of the brain and spinal cord were removed for histological processing and Hematoxylin-Eosin and Ziehl-Neelsen staining. Histopathological analysis of the brain and spinal cord, based on histological sections stained with Hematoxylin-Eosin, pronounced and diffuse edema in these tissues, and congestion, degeneration, and focal necrosis of the cerebral cortex. The present study describes lymphocytic meningoencephalomyelitis associated with infection by Myxobolus sp. in the central nervous system of Eigenmannia sp.


2021 ◽  
Vol 65 (3) ◽  
pp. 15-21
Author(s):  
O. O. Igado ◽  
S. F. Braimah ◽  
A. A. Obasa

Abstract The African pygmy hedgehog (Atelerix albiventris) is an insectivorous animal, native to Africa. The central nervous system (CNS) consists of the brain and the spinal cord, protected by the cranium and vertebral column respectively. Assessment of the gross appearance and morphometries of the African pygmy hedgehog CNS were carried out using six adults (3 males and 3 females). The gross examination showed the brains to be lissencephalic, with relatively large olfactory bulbs, similar to that observed in some rodents. The rootlets of the first cervical spinal nerves were observed to emerge before the foramen magnum. Linear measurements were obtained from both the brain and spinal cord. The mean weight of the animals was 199.00 ± 16.09 g, with the males having an average body weight of 183.50 ± 12.02 g and the females 206.80 ± 11.95 g. Although not statistically significant, the males had a higher encephalisation quotient (0.40 ± 0.08) relative to the females 0.36 ± 0.04). The values for the brain weight, length of spinal cord and heights of the telencephalon and diencephalon at different points were higher in the males, while the spinal cord weight, length of brain and cerebellar height were higher in the females. The spinal cord showed slight enlargements at the cervical, thoracic, lumbar and sacral segments. This study aimed to provide baseline data for the study of the gross appearance and neuromorpho-metrics of the hedgehog, with possible application in regional anaesthesiology and comparative wildlife neuroanatomy.


Parasitology ◽  
1955 ◽  
Vol 45 (1-2) ◽  
pp. 31-40 ◽  
Author(s):  
J. F. A. Sprent

A wide variety of nematode species have been observed to invade the central nervous system. They may be located in the meningeal spaces or may penetrate into the tissues of the brain and spinal cord.The pathological changes resulting from invasion of the central nervous system are influenced by the route of entry, the size and the mobility of the parasite. They may be diffuse or focal and may include haemorrhage, degenerative changes, cellular infiltration and glial proliferation. Such changes may or may not be observed in close association with the parasite.Symptoms indicating involvement of the central nervous system have long been associated with nematode infections outside the central nervous system. The pathogenesis of these symptoms is obscure, but they may possibly be of allergic origin.The direct pathological effects on the central nervous system are mainly the result of trauma and are directly proportional to the size and activity of the parasite. The possibility that nematodes may transport viruses into the central nervous system is briefly discussed.


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