China 
Africa 
Explore chapters and articles related to this topic
Intraoperative Optical Guidance for Neurosurgery
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Chia-Pin Liang, Cha-Min Tang, Yu Chen
Jafri et al. further demonstrated that the side-viewing OCT probe can be used for guiding deep brain tissue dissection and injection in vivo (Jafri et al., 2009). Figure 21.3 shows the injection of adeno-associated virus carrying enhanced green fluorescent protein (AAV2-EGFP) to either the dentate subiculum or CA1 region of a rat hippocampus. In vivo OCT image at the injection site is shown on the right (Figure 21.3b, d, and f), and a postmortem photomicrograph showing the fluorescent cells superimposed on the corresponding brightfield image is on the left (Figure 21.3a, c and e). The circle to the left of the probe is the injection needle. The location of the transfected cells exactly matches the OCT image of the needle tip with respect to the structure of the dentate (Figure 21.3a). Similarly, the tissue structure and needle position shown in the OCT images of the subiculum (Figure 21.3c) and CA1 region (Figure 21.3e) correlate with the location of the transfected cells (Figure 21.3d and f, respectively). These experiments show that OCT image confirms the location of the instrument at the time of intervention and also monitors the injection that cannot otherwise be carried out.
Spatial Orientation and Disorientation
Published in Anthony N. Nicholson, The Neurosciences and the Practice of Aviation Medicine, 2017
Groups of head direction cells appear to be networked in that all cells tend to drift by similar amounts in the same direction. When the light is switched on again, the initial preferred firing direction of the cell is restored within 80 milliseconds. This observation raises an interesting parallel with a phenomenon known to aircrew as ‘the leans’ which involves an erroneous sense of roll attitude after manoeuvring in cloud and which is rapidly dispelled once a view of the ground is regained. Thus head direction cells are behaving as a form of internal compass that is maintained not by the Earth’s magnetic field but by visual, locomotor and vestibular cues. The afferent signal from the semicircular canals conveys information about head angular velocity. Cells similarly coded for head angular velocity can be found in brainstem nuclei, in particular the medial vestibular nucleus, the dorsal tegmental nucleus and the lateral mammillary nucleus. Angular velocity of the head derived from vestibular inputs has a significant influence on head direction cell activity. Neurotoxic lesions to the vestibular system abolish the head direction signal in the anterodorsal thalamic nucleus and the posterior subiculum and, in addition, disrupt location-specific firing of place cells in the hippocampus (Taube, 2007).
Biotechnology: Tuning Nanoscale Bio-systems
Published in Paula V. Messina, Luciano A. Benedini, Damián Placente, Tomorrow’s Healthcare by Nano-sized Approaches, 2020
Paula V. Messina, Luciano A. Benedini, Damián Placente
Biological-based approaches, such as stem cell transplantation, are therefore receiving increasing attention to treat complex diseases that affect multiple pathways and regions (Blurton-Jones et al. 2014); so, they can also be benefited by genetic manipulation. The use of adenoviral vectors to deliver human tissue kallikrein (KLK1) gene or KLK1 protein infusion into injured tissues of animal models has provided particularly encouraging results in attenuating or reversing myocardial, renal and cerebrovascular ischemic phenotype and tissue damage. Such investigations pave the way for the administration of genetically modified mesenchymal stem cells (MSCs) or endothelial progenitor cells (EPCs) with the human tissue kallikrein (KLK1) gene. Collectively, findings from pre-clinical studies raise the possibility that tissue KLK1 may be a novel future therapeutic target in the treatment of a wide range of cardiovascular, cerebrovascular and renal disorders (Devetzi et al. 2018). On the other hand, enhancing endogenous synaptic connectivity in transgenic mice with Alzheimer’s disease (AD) was obtained by the use of genetically modified neural stem cell (NSCs). NSCs that were stable to express and secrete a beta-amyloid Aβ-degrading enzyme, neprilysin (sNEP), provides a marked and significant reduction in Aβ pathology and increases synaptic density after implantation on both 3xTg-AD and Thy1-APP transgenic mice. Remarkably, Aβ plaque loads are reduced not only in the hippocampus and in subiculum adjacent to engrafted NSCs, but within the amygdala and medial septum, areas that receive afferent projections from the engrafted region (Blurton-Jones et al. 2014).
A boundary vector cell model of place field repetition
Published in Spatial Cognition & Computation, 2018
Roddy M Grieves, Éléonore Duvelle, Paul A Dudchenko
Following the introduction of the BVC model, neurons similar to BVCs have been observed in a number of brain regions including the subiculum (Barry et al., 2006; Lever, Burton, Jeewajee, O’Keefe & Burgess, 2009; Sharp, 1999; Stewart, Jeewajee, Wills, Burgess & Lever, 2014), parasubiculum (Boccara et al., 2010; Solstad, Boccara, Kropff, Moser & Moser, 2008), medial entorhinal cortex (mEC) (Bjerknes, Moser & Moser, 2014; Savelli, Yoganarasimha & Knierim, 2008; Solstad et al., 2008), and recently the rostral thalamus (Jankowski et al., 2015) and anterior claustrum (Jankowski & O’Mara, 2015) (Figure 2). These “boundary” cells have a preferred firing direction, much like head direction (HD) cells, but instead of firing maximally when the animal’s head is facing this direction, a given boundary cell will fire when an environmental boundary lies in that direction from the animal. This firing is driven by the boundary’s position relative to the animal, presumably based on self-motion information. Consistent firing is observed in every environment where the cell is recorded, provided that the external reference frame is maintained. For instance, consistent boundary fields are anticipated if each environment is placed in the same curtain enclosure with the same distal cue card (Lever et al., 2009; Sharp, 1997). Environmental boundaries which can drive cell firing in this way may be walls, low ridges, or vertical drops and the color, texture, or odor of these does not seem to influence the cell’s firing (Lever et al., 2009).
A mobile robot mapping model inspired from the place cells functionality of hippocampus based on dimension reduction technique
Published in Journal of Experimental & Theoretical Artificial Intelligence, 2021
This paper propose a model for representing a map in a mobile robot. Several types of cell are involved in making a map in the brain. The most important of them is place cell in the hippocampus. Considering ventral visual pathway, this paper models V1 section, entorhinal cortex and hippocampus as it is shown in Figures 8 and 9, respectively. As it can be seen, place cells are connected entorhinal cortex through subiculum, but for simplicity of the model, subiculum is ignored.
Static electric field exposure decreases white blood cell count in peripheral blood through activating hypothalamic–pituitary–adrenal axis
Published in International Journal of Environmental Health Research, 2022
Jiahong Wu, Li Dong, Junli Xiang, Guoqing Di
One significant mechanism for HPA axis habituation is CORT-mediated negative feedback (Tasker and Herman 2011). As the main sites of CORT-mediated negative feedback, both the hypothalamus and the pituitary contain abundant GRs, which allows them to respond to excessive CORT by forming a CORT-GR complex (Laryea et al. 2015). In the parvocellular neurons of the hypothalamus, the CORT-GR complex could repress the expression of CRH gene by binding to the negative glucocorticoid response element (nGRE) in the CRH promoter (Webster and Cidlowski 1999). The inhibition of CRH gene expression would reduce its own subsequent synthesis (Kim and Iremonger 2019). In the basophilic cells of the pituitary, the CORT-GR complex could suppress the expression of Proopiomelanocortin (POMC) gene by binding to the nGRE in the POMC promoter (Webster and Cidlowski 1999). Since POMC is the precursor of ACTH (Pecori et al. 2011), the inhibition of POMC gene expression can reduce the synthesis of ACTH (Grissom and Bhatnagar 2009). With the synthesis of CRH and ACTH recovered, the stimulatory effect of ACTH on CORT synthesis was attenuated, and the HPA axis activation magnitude declined (Kim and Iremonger 2019). The regulation of stress-related neural circuitry is another important mechanism of HPA axis habituation (Grissom and Bhatnagar 2009). Among the stress-related neural circuitry, the posterior paraventricular thalamus (pPVT) is a key structure of HPA axis habituation under the condition of chronic stress (Hsu et al. 2014). The pPVT could receive afferent inputs originating from the parabrachial nucleus, locus coeruleus, dorsal raphe and the periaqueductal gray. Through integrating these afferent inputs, the pPVT could judge whether the stressor is a homotypic stressor or a heterotypic stressor (Mccarty 2016). Once the pPVT identifies that the stressor is a homotypic stressor, it projects signals to the medial prefrontal cortex and the ventricular subiculum. The signals of these two regions could be integrated by the bed nucleus of the stria terminalis and then projected to the paraventricular nucleus of the hypothalamus (PVN). As the control center of HPA axis activity, the PVN decreases the HPA axis activation magnitude. On the basis of the analysis above, it is concluded that the HPA axis habituation to SEF exposure in this study involves multiple mechanisms including CORT-mediated negative feedback and the regulation of stress-related neural circuitry.