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Brain swelling, raised intracranial pressure and hypoxia-related brain injury
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
Dark neurons in contrast have the following attributes (Figure 12.16):A monotonous, often shrunken appearance.Basophilic with H&E staining, having a dark blue perikaryal and dendritic cytoplasm.Slight eosinophilia may be superimposed giving a dark blue-red tint with H&E staining stain.Apical dendrites may have an irregular, corkscrew-shaped appearance.The shrunken, dark-stained nucleus may be indistinct within the cell body since it blends into the compacted perikaryal cytoplasm.Nucleoli though still discernable.Affected neurons may be separated from adjacent neuropil, especially with paraffin embedded tissue and are often scattered among histologically normal neurons (Jortner 2006).
Neurons
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Neurons also differ greatly in the shapes and sizes of their cell bodies and in the extent of their dendritic and axonal arborizations. Neuronal cell bodies may be round, oblong, fusiform, or pyramidal in shape. The structure of pyramidal cells (Figure 7.1c), found in the cerebral cortex, hippocampus, and amygdala, differs somewhat between different regions but is characterized by two sets of dendrites: Basal dendrites that arise from the base of the pyramidal cell body and then branch more extensively, andA single thick apical dendrite of a few microns diameter that stems from the apex of the pyramid and branches with distance away from the cell body and terminates in what is referred to as a distal tuft or tuft dendrites. Some dendrites branch from the trunk of the apical dendrite and are referred to as oblique dendrites.
Human Brain-Computer Interface
Published in Alexa Riehle, Eilon Vaadia, Motor Cortex in Voluntary Movements, 2004
Gert Pfurtscheller, Christa Neuper, Niels Birbaumer
The family of SCPs originates in the upper layers (layers I and II) of the cortex. However, slow potential changes, probably of the same origin, can be found in all parts of the nervous system. Whether the mechanisms of physiological generation are the same is still a matter of debate. The apical dendrites receive most of their input from intracortical fibers, callosal input from the other hemisphere, and input from the medial and reticular thalamus, the so-called nonspecific ascending activation system. Cholinergic inflow to the apical dendrites arrives primarily from structures in the basal forebrain and the basal ganglia.24 The amplitudes of slow cortical potentials are highly sensitive to the manipulation of cholinergic, monoaminergic, and glutamatergic transmission. SCPs tending toward the negative reflect slow EPSP and glial potentials and, therefore, indicate longer-lasting depolarization of the dendritic network. SCPs tending toward the positive are more difficult to analyze because they may result from a reduction of inflow to the apical dendrites, or, probably in rare occasions, from direct inhibitory activity at the level of layer I or II. Finally, SCPs tending toward the positive may indicate the inversion of the cortical dipole between the upper input layers and the lower output layers of the cortex.25 Therefore, the interpretation of slow potentials tending toward the positive requires a description of the experimental and physiological context of recording. Note also that in areas where the convexity of the cortex results in an inversion of the usual cortical dipole directions, such as in the orbitofrontal cortex, the inferior temporal cortex, part of area 17 of the occipital cortex, and the interhemispheric sulcus, inversion of the polarity of slow cortical potentials may be found. Therefore, polarity changes recorded at electrodes from the scalp alone can only be interpreted with great caution. Birbaumer et al.24 have described a frontal corticothalamic and basal ganglia network responsible for the attentional regulation of all types of preparatory SCPs. They have shown that slow cortical potentials are part of an excitatory and
The effect of experimentally-induced diabetes on rat hippocampus and the potential neuroprotective effect of Cerebrolysin combined with insulin. A histological and immunohistochemical study
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Doaa El-Adli, Salwa A. Gawish, Amany AbdElFattah Mohamed AbdElFattah, Mona Fm. Soliman
The hippocampal formation consisted of hippocampus proprius, dentate gyrus (DG) and the subicular cortex (SC). The hippocampus proprius could be differentiated into CA1, CA2, CA3 and CA4 regions. The DG had a crest and upper and lower blades surrounding CA4 (Figure 1 (a and b)). The hippocampus proprius was formed of the following layers; the alveus, stratum oriens (st.or), stratum pyramidale (st.py), stratum radiatum (st.rd) and stratum lacunosum-moleculare (st.lm). The alveus was the innermost layer containing nerve fibers and neuroglial cells. St.or showed scattered cells within the nerve fibers. St.py consisted of 5–6 layers of pyramidal cells. St.rd showed a radial streaking pattern of fibers. Finally, St.lm showed horizontal fibers, neuroglial cells and blood vessels (Figure 1 (c)). Pyramidal cells of CA3 appeared as large sized, loosely packed triangular cells with vesicular nuclei and prominent nucleoli. Each cell showed an apical dendrite ramifying toward St.rd and basal dendrites (Figure 1 (d)). The DG consisted of molecular, granular and polymorphic layers. The polymorphic layer showed scattered polymorphic nuclei. The granule cell layer (GCL) contained 8–9 compactly arranged layers of granule cells with vesicular nuclei and prominent nucleoli. Spindle-shaped immature cells with oval darkly stained nuclei were seen in the subgranular zone (SGZ) (Figure 1 (e and f)).
Better understanding the neurobiology of primary lateral sclerosis
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2020
P. Hande Ozdinler, Mukesh Gautam, Oge Gozutok, Csaba Konrad, Giovanni Manfredi, Estela Area Gomez, Hiroshi Mitsumoto, Marcella L. Erb, Zheng Tian, Georg Haase
The third important characteristic of UMNs is their long apical dendrite that extends toward the top layers of the cortex (Figure 1(B–C)). The apical dendrite is exceptionally important for their neuronal modulation, as this is the site for many different neuron populations to make a synaptic connection with the UMNs (28). The apical dendrite is extensively branched and the branches are adorned with hundreds of thousands, of spines (Figure 1(C)). These spines receive excitatory input from many different neuron types, such as callosal projection neurons, thalamacortical neurons and local circuitry neurons (Figure 1(B)) and (29). Thus, the health and stability of spines are important for these excitatory neurons to convey their information. Especially at the site of layer 2/3, CSMN receive most of their excitatory input, and this is one of their unique characteristics (30,31). The connectivity patterns of both long-distance projection neurons and local circuitry neurons are investigated by novel approaches, revealing the complex connectivity dynamics in the motor cortex and other regions (32,33).
Combination of tea polyphenols and proanthocyanidins prevents menopause-related memory decline in rats via increased hippocampal synaptic plasticity by inhibiting p38 MAPK and TNF-α pathway
Published in Nutritional Neuroscience, 2022
Qian Yang, Yusen Zhang, Luping Zhang, Xuemin Li, Ruirui Dong, Chenmeng Song, Le Cheng, Mengqian Shi, Haifeng Zhao
The essence of learning and memory is the conduction and processing of nerve signals. The dynamic turnover of spines, termed structural plasticity, is also involved with learning and memory. The formation and elimination of dendritic spines rewire neural circuits by establishing or abolishing connections in the brain during learning experiences [36]. A study showed that Oral administration with 10 and 50 mg/kg TP prevented the number of apical dendrites of pyramidal neurons and spines along those dendrites in the CA1 region of the hippocampus changes induced by LPS [37]. Expressions of phosphorylated neurofilament-H (P-NF-H, axon marker), microtubule-associated proteins (MAP) 2a and 2b (MAP2; dendrite marker) and synaptophysin were increased in the brains of SAMP8-administered PC oligomers 50 mg/kg for 5 weeks [38]. In this experiment, TP can greatly improve the damage of dendrite length and dendrite spine density in memory decline rats, while PC can significantly improve the branches of dendrites. It is interesting that the dendrite length, the number of dendrite branches and the density of dendritic spines were markedly improved in the combined intervention of TP and PC than that in TP or PC single treatment group. Preservation of thin and mushroom spine density appears to be important for cognitive maintenance [39]. In our study, since the scanning pictures failed to clearly score the morphology of dendritic spines, the subsequent experiments will continue to observe the morphology of dendritic spines through oil immersion lens, statistics the density of dendritic spines of various morphologies, and improve the Golgi-staining results.