A new look at the architecture and dynamics of the Hydra nerve net.

The Hydra nervous system is the paradigm of a 'simple nerve net'. Nerve cells in Hydra, as in many cnidarian polyps, are organized in a nerve net extending throughout the body column. This nerve net is required for control of spontaneous behavior: elimination of nerve cells leads to polyps that do not move and are incapable of capturing and ingesting prey (Campbell, 1976). We have re-examined the structure of the Hydra nerve net by immunostaining fixed polyps with a novel antibody that stains all nerve cells in Hydra. Confocal imaging shows that there are two distinct nerve nets, one in the ectoderm and one in the endoderm, with the unexpected absence of nerve cells in the endoderm of the tentacles. The nerve nets in the ectoderm and endoderm do not contact each other. High-resolution TEM (transmission electron microscopy) and serial block face SEM (scanning electron microscopy) show that the nerve nets consist of bundles of parallel overlapping neurites. Results from transgenic lines show that neurite bundles include different neural circuits and hence that neurites in bundles require circuit-specific recognition. Nerve cell-specific innexins indicate that gap junctions can provide this specificity. The occurrence of bundles of neurites supports a model for continuous growth and differentiation of the nerve net by lateral addition of new nerve cells to the existing net. This model was confirmed by tracking newly differentiated nerve cells.

Abnormal changes in gray matter volume and structural covariate network in patients with chronic pontine infarction / 国际脑血管病杂志

Objective:To investigate the changes in gray matter volume (GMV) and abnormalities in structural covariant network (SCN) patterns in patients with chronic pontine infarction (PI).Methods:Patients with unilateral chronic PI (case group) with the first onset admitted to the First Affiliated Hospital of Zhengzhou University and Tianjin Medical University General Hospital from October 2014 to June 2021 were prospectively included. At the same time, healthy subjects matched with age, gender and education years (normal control group) were included. High-resolution three-dimensional T 1 structural MRI images and behavioral scores of the subjects were collected. The voxel-based morphometry and two-sample t test were used to explore the differences in GMV between the groups. Using GMV differential brain regions as seed points, SCN was constructed to explore the abnormality of structural covariant patterns in patients with PI. Spearman rank correlation analysis was used to analyze the correlation between GMV in differential brain regions and behavioral scores. Results:A total of 60 patients with PI were enrolled, including 33 left PI and 27 right PI, while 34 healthy controls were also enrolled. Compared with the normal control group, the GMV in bilateral posterior cerebellar lobe decreased significantly in the left PI group, and the GMV in left anterior and posterior cerebellar lobes and the right posterior cerebellar lobe decreased significantly in the right PI group (Gaussian random field correction with voxel level P<0.001 and cluster level P<0.05, cluster voxel >20), and there was a significant correlation between GMV values in the left anterior and posterior cerebellar lobes and the right posterior cerebellar lobe and the motor function score ( P<0.05). In addition, compared with the normal control group, the right PI group had broader covariate brain regions and a significant increase in the number of structural connections between covariate brain regions (family-wise error correction with voxel level P<0.05, cluster voxel >20). Conclusions:The GMV in bilateral posterior cerebellar lobe decreases significantly in patients with chronic PI, and were secondary to broader covariate brain regions and structural connections. This may be the neural mechanism of impaired behavioral function in patients with PI.

An atlas of the germ ball-cercaria-schistosomulum transition in Schistosoma mansoni, using confocal microscopy and in situ hybridisation.

Schistosomes are complex platyhelminth parasites with a genome comprising ∼12,000 protein-coding genes, three distinct generations, and at least seven distinct phenotypes. We chart here cellular and gene expression changes associated with development of the cercaria, in the intramolluscan daughter sporocyst, and its transformation into the skin stage schistosomulum upon infection of the mammalian host. We describe the morphology of the early daughter sporocyst and the increasing complexity of cellular organisation in germ balls as they rapidly develop into cercariae. We show how individual myocytes differentiate and combine to create the complex musculature of the head capsule and body wall. In situ hybridisation reveals that some transcripts encoding the secretory proteins, released during skin penetration, are expressed in gland-cell precursors very early in germ ball development. However, those for the projected anti-inflammatory protein Sm16-stathmin are widely expressed in germ ball tissues, suggesting the protein has intracellular functions. Transcripts for smkk7 are expressed in six cells of the larval body, while the KK7 protein is present throughout the peripheral nerve net, including sensory nerve bulbs, providing a marker for the nerve net in adult worms. We also note that the cercaria-schistosomulum transformation is accompanied by tissue remodelling without growth.

Phylogenetics of swimming behaviour in Medusozoa: the role of giant axons and their possible evolutionary origin.

Although neural tissues in cnidarian hydroids have a nerve net structure, some cnidarian medusae contain well-defined nerve tracts. As an example, the hydrozoan medusa Aglantha digitale has neural feeding circuits that show an alignment and condensation, which is absent in its relatives Aequorea victoria and Clytia hemisphaerica. In some cases, neural condensations take the form of fast propagating giant axons concerned with escape or evasion. Such giant axons appear to have developed from the fusion of many, much finer units. Ribosomal DNA analysis has identified the lineage leading to giant axon-based escape swimming in Aglantha and other members of the Aglaura clade of trachymedusan jellyfish. The Aglaura, along with sister subclades that include species such as Colobonema sericeum, have the distinctive ability to perform dual swimming, i.e. to swim at either high or low speeds. However, the form of dual swimming exhibited by Colobonema differs both biomechanically and physiologically from that in Aglantha and is not giant axon based. Comparisons between the genomes of such closely related species might provide a means to determine the molecular basis of giant axon formation and other neural condensations. The molecular mechanism responsible may involve 'fusogens', small molecules possibly derived from viruses, which draw membranes together prior to fusion. Identifying these fusogen-based mechanisms using genome analysis may be hindered by the many changes in anatomy and physiology that followed giant axon evolution, but the genomic signal-to-noise ratio may be improved by examining the convergent evolution of giant axons in other hydrozoa, such as the subclass Siphonophora.

Neuroecology beyond the brain: learning in Echinodermata.

We propose an expansion of neuroecological comparisons to include the capabilities of brainless and non-neural organisms. We begin this enterprise by conducting a systematic search for studies on learning in echinoderms. Echinodermata are marine invertebrates comprising starfish, brittle stars, sea cucumbers, sea urchins, and sea lilies. Animals in this phylum lack any centralized brain and instead possess diffuse neural networks known as nerve nets. The learning abilities of these animals are of particular interest as, within the bilaterian clade, they are close evolutionary neighbors to chordates, a phylum whose members exhibit complex feats in learning and contain highly specialized brains. The learning capacities and limitations of echinoderms can inform the evolution of nervous systems and learning in Bilateria. We find evidence of both non-associative and associative learning (in the form of classical conditioning) in echinoderms, which was primarily focused on starfish. Additional evidence of learning is documented in brittle stars, sand dollars, and sea urchins. We then discuss the evolutionary significance of learning capabilities without a brain, the presence of embodied cognition across multiple groups, and compare the learning present in echinoderms with the impressive cognitive abilities documented in the oldest linage group within vertebrates (the major group within the phylum of chordates), fish.

Characterization of geometric variance in the epithelial nerve net of the ctenophore Pleurobrachia pileus.

Neuroscience lacks a diverse repertoire of model organisms, resulting in an incomplete understanding of the general principles of neural function. Ctenophores display many neurobiological and experimental features which make them a promising candidate to fill this gap. They possess a nerve net distributed across their body surface in the epithelial layer. There is a long-held assumption that nerve nets are "simple" and lack distinct organizational principles. We want to challenge this assumption and determine how stereotyped the structure of this network is. We estimated body surface area in Pleurobrachia pileus using custom optical projection tomography and light sheet morphometry imaging systems. Using an antibody against tyrosinated α-tubulin, we visualized the nerve net in situ and quantified the geometric properties using an automated segmentation approach. We characterized organizational rules of the epithelial nerve net in animals of different sizes and at different regions of the body. We found that specific morphological features within the nerve net are largely unchanged during growth. These properties must be essential to the functionality of the nervous system and therefore are maintained during a change in body size. We have also established the principles of organization of the network and showed that some of the geometric properties are variable across different parts of the body. This suggests that there may be different functions occurring in regions with different structural characteristics. This is the most comprehensive structural description of a ctenophore nerve net to date and demonstrates the amenability of P. pileus for whole organism network analysis.

Study of altered brain metabolism and connectivity in temporal lobe epilepsy / 中华核医学与分子影像杂志

Objective:To explore the abnormal brain metabolic pattern and connectivity in temporal lobe epilepsy (TLE) patients.Methods:18F-FDG PET images of 75 patients diagnosed as drug resistant unilateral TLE from January 2014 to December 2016 in Huashan Hospital of Fudan University were collected retrospectively, including 41 (22 males, 19 females, age (28.4±8.7) years) left TLE (LTLE) and 34 (13 males, 21 females, age (28.5±8.8) years) right TLE (RTLE). Forty-four healthy controls (24 males, 20 females, age (31.2±6.2) years) were also enrolled. The cerebral glucose metabolism in TLE patients and the controls were analyzed with statistical parametric mapping (SPM) 12. The brain connectivity based on glucose metabolism were analyzed with bilateral hippocampus and amygdala as seeds. Permutation test with 1 000 permutations was used to analyze data. Results:Compared to control group, in both LTLE and RTLE groups, hypometabolism was found in affected hippocampus, amygdala, insula and temporal gyrus and hypermetabolism was observed in health hippocampus, parahippocampal gyrus, amygdala, lenticular nucleus and thalamus. In addition, hypometabolism was also found in affected superior/middle frontal gyrus and hypermetabolism was also found in bilateral frontal-orbital gyrus, bilateral cerebellum, affected lenticular nucleus and thalamus in LTLE group. In both TLE groups, affected seeds exhibited increased connectivity with affected superior frontal gyrus, lingual gyrus, fusiform gyrus, superior/middle temporal gyrus and temporal pole (all P<0.05); affected seeds exhibited increased connectivity with health superior frontal gyrus ( P=0.005), lingual gyrus ( P=0.018) and transverse temporal gyrus ( P=0.016) in RTLE group in addition. Besides, affected seeds exhibited decreased connectivity with bilateral default mode network (DMN) (all P<0.05), affected caudate nucleus ( P=0.015) and health thalamus ( P=0.008), in a uniform distribution pattern in LTLE group, and with bilateral cerebral cortex in an irregular distribution pattern in RTLE group (all P<0.05). In LTLE group, health seeds exhibited more increased connections with superior ( P=0.005)/middle frontal gyrus ( P=0.042), health hippocampus ( P=0.038), parahippocampal gyrus ( P=0.019), amygdala ( P=0.038), posterior cingulate gyrus ( P=0.004), and bilateral fusiform gyrusand ( P=0.048) compared with RTLE group; while, in RTLE group, health seeds exhibited more decreased connections with health superior ( P=0.047), inferior frontal gyrus ( P<0.001), orbital frontal gyrus ( P<0.001) and rectus gyrus ( P=0.016) compared with LTLE group. Conclusion:Altered brain glucose metabolism and connectivity pattern are found and will elucidate the underlying metabolic pattern of TLE.

Five-Class Classification of Cervical Pap Smear Images: A Study of CNN-Error-Correcting SVM Models.

OBJECTIVES: Different complex strategies of fusing handcrafted descriptors and features from convolutional neural network (CNN) models have been studied, mainly for two-class Papanicolaou (Pap) smear image classification. This paper explores a simplified system using combined binary coding for a five-class version of this problem. METHODS: This system extracted features from transfer learning of AlexNet, VGG19, and ResNet50 networks before reducing this problem into multiple binary sub-problems using error-correcting coding. The learners were trained using the support vector machine (SVM) method. The outputs of these classifiers were combined and compared to the true class codes for the final prediction. RESULTS: Despite the superior performance of VGG19-SVM, with mean ± standard deviation accuracy and sensitivity of 80.68% ± 2.00% and 80.86% ± 0.45%, respectively, this model required a long training time. There were also false-negative cases using both the VGGNet-SVM and ResNet-SVM models. AlexNet-SVM was more efficient in terms of running speed and prediction consistency. Our findings also showed good diagnostic ability, with an area under the curve of approximately 0.95. Further investigation also showed good agreement between our research outcomes and that of the state-of-the-art methods, with specificity ranging from 93% to 100%. CONCLUSIONS: We believe that the AlexNet-SVM model can be conveniently applied for clinical use. Further research could include the implementation of an optimization algorithm for hyperparameter tuning, as well as an appropriate selection of experimental design to improve the efficiency of Pap smear image classification.

A genetically tractable jellyfish model for systems and evolutionary neuroscience.

Jellyfish are radially symmetric organisms without a brain that arose more than 500 million years ago. They achieve organismal behaviors through coordinated interactions between autonomously functioning body parts. Jellyfish neurons have been studied electrophysiologically, but not at the systems level. We introduce Clytia hemisphaerica as a transparent, genetically tractable jellyfish model for systems and evolutionary neuroscience. We generate stable F1 transgenic lines for cell-type-specific conditional ablation and whole-organism GCaMP imaging. Using these tools and computational analyses, we find that an apparently diffuse network of RFamide-expressing umbrellar neurons is functionally subdivided into a series of spatially localized subassemblies whose synchronous activation controls directional food transfer from the tentacles to the mouth. These data reveal an unanticipated degree of structured neural organization in this species. Clytia affords a platform for systems-level studies of neural function, behavior, and evolution within a clade of marine organisms with growing ecological and economic importance.

Multiple neuronal networks coordinate Hydra mechanosensory behavior.

Hydra vulgaris is an emerging model organism for neuroscience due to its small size, transparency, genetic tractability, and regenerative nervous system; however, fundamental properties of its sensorimotor behaviors remain unknown. Here, we use microfluidic devices combined with fluorescent calcium imaging and surgical resectioning to study how the diffuse nervous system coordinates Hydra's mechanosensory response. Mechanical stimuli cause animals to contract, and we find this response relies on at least two distinct networks of neurons in the oral and aboral regions of the animal. Different activity patterns arise in these networks depending on whether the animal is contracting spontaneously or contracting in response to mechanical stimulation. Together, these findings improve our understanding of how Hydra's diffuse nervous system coordinates sensorimotor behaviors. These insights help reveal how sensory information is processed in an animal with a diffuse, radially symmetric neural architecture unlike the dense, bilaterally symmetric nervous systems found in most model organisms.

Characterization of the dynamics and variability of neuronal subtype responses during growth, degrowth, and regeneration of Nematostella vectensis.

BACKGROUND: The ability to regenerate body parts is a feature of metazoan organisms and the focus of intense research aiming to understand its basis. A number of mechanisms involved in regeneration, such as proliferation and tissue remodeling, affect whole tissues; however, little is known on how distinctively different constituent cell types respond to the dynamics of regenerating tissues. Preliminary studies suggest that a number of organisms alter neuronal numbers to scale with changes in body size. In some species with the ability of whole-body axis regeneration, it has additionally been observed that regenerates are smaller than their pre-amputated parent, but maintain the correct morphological proportionality, suggesting that scaling of tissue and neuronal numbers also occurs. However, the cell dynamics and responses of neuronal subtypes during nervous system regeneration, scaling, and whole-body axis regeneration are not well understood in any system. The cnidarian sea anemone Nematostella vectensis is capable of whole-body axis regeneration, with a number of observations suggesting the ability to alter its size in response to changes in feeding. We took advantage of Nematostella's transparent and "simple" body plan and the NvLWamide-like mCherry fluorescent reporter transgenic line to probe the response of neuron populations to variations in body size in vivo in adult animals during body scaling and regeneration. RESULTS: We utilized the previously characterized NvLWamide-like::mCherry transgenic reporter line to determine the in vivo response of neuronal subtypes during growth, degrowth, and regeneration. Nematostella alters its size in response to caloric intake, and the nervous system responds by altering neuronal number to scale as the animal changes in size. Neuronal numbers in both the endodermal and ectodermal nerve nets decreased as animals shrunk, increased as they grew, and these changes were reversible. Whole-body axis regeneration resulted in regenerates that were smaller than their pre-amputated size, and the regenerated nerve nets were reduced in neuronal number. Different neuronal subtypes had distinct responses during regeneration, including consistent, not consistent, and conditional increases in number. Conditional responses were regulated, in part, by the size of the remnant fragment and the position of the amputation site. Regenerates and adults with reduced nerve nets displayed normal behaviors, indicating that the nerve net retains functionality as it scales. CONCLUSION: These data suggest that the Nematostella nerve net is dynamic, capable of scaling with changes in body size, and that neuronal subtypes display differential regenerative responses, which we propose may be linked to the scale state of the regenerating animals.

Frequency-Dependent Intrinsic Electrophysiological Functional Architecture of the Human Verbal Language Network.

Functional magnetic resonance imaging (fMRI) allowed the spatial characterization of the resting-state verbal language network (vLN). While other resting-state networks (RSNs) were matched with their electrophysiological equivalents at rest and could be spectrally defined, such correspondence is lacking for the vLN. This magnetoencephalography (MEG) study aimed at defining the spatio-spectral characteristics of the neuromagnetic intrinsic functional architecture of the vLN. Neuromagnetic activity was recorded at rest in 100 right-handed healthy adults (age range: 18-41 years). Band-limited power envelope correlations were performed within and across frequency bands (θ, α, ß, and low γ) from a seed region placed in the left Broca's area, using static orthogonalization as leakage correction. K-means clustering was used to segregate spatio-spectral clusters of resting-state functional connectivity (rsFC). Remarkably, unlike other RSNs, within-frequency long-range rsFC from the left Broca's area was not driven by one main carrying frequency but was characterized by a specific spatio-spectral pattern segregated along the ventral (predominantly θ and α) and dorsal (ß and low-γ bands) vLN streams. In contrast, spatial patterns of cross-frequency vLN functional integration were spectrally more widespread and involved multiple frequency bands. Moreover, the static intrinsic functional architecture of the neuromagnetic human vLN involved clearly left-hemisphere-dominant vLN interactions as well as cross-network interactions with the executive control network and postero-medial nodes of the DMN. Overall, this study highlighted the involvement of multiple modes of within and cross-frequency power envelope couplings at the basis of long-range electrophysiological vLN functional integration. As such, it lays the foundation for future works aimed at understanding the pathophysiology of language-related disorders.

[Fractional amplitude of low-frequency fluctuations in retinal vein occlusion: a resting-state fMRI study].

Objective: To investigate the altered spontaneous brain activity in patients with retinal vein occlusion (RVO) during the resting state. Methods: A case-control study. Forty-five patients with RVO [24 males and 21 females; age, (51.24±5.86) years] diagnosed from May 2018 to July 2019 in Renmin Hospital of Wuhan University were recruited in the RVO group. Meanwhile, forty-three healthy controls [19 males and 24 females; age, (49.79±7.31) years] who were closely matched in age and sex to patients with RVO were recruited in the healthy control group. Each subject underwent a whole-brain resting-state functional magnetic resonance imaging scan to detect the values of fractional amplitude of low-frequency fluctuations (fALFF). The altered spontaneous brain activity between RVO patients and healthy controls were analyzed. The intra-and inter-group comparisons of two sets of fALFF values were conducted using one-sample t-test and two-sample t-test, respectively. Results: Compared with the healthy control group, the fALFF values of RVO patients were significantly changed. The fALFF values of left cerebellum (-0.68±0.48, t=3.8081), right cerebellum (-0.79±0.47, t=4.590), right brainstem (-0.57±0.50, t=3.964) and left insula (-0.22±0.27, t=3.587) increased, while the fALFF values of right calcarinesulcus (0.60±0.72, t=-3.521), right thalamus (-0.68±0.43, t=-3.846) and left lingual gyrus (-0.12±0.33, t=-3.876) decreased. The differences were statistically significant (voxel-level P<0.01, Gaussian random field correction, cluster-level P<0.05). Conclusions: Patients with RVO have abnormal spontaneous neural activity in multiple brain areas, including visual pathways and emotion-cognition processing regions. Moreover, there may be compensatory brain function enhancement in local brain areas. The results provide new insights into the understanding of the mechanism for the occurrence and development of RVO.(Chin J Ophthalmol, 2020, 56:266-271).

Immunocytochemical localization of a putative strychnine-sensitive glycine receptor in Hydra vulgaris.

Previous biochemical studies have identified strychnine-sensitive glycine receptors in membrane preparations of Hydra vulgaris (Cnidaria: Hydrozoa). Electrophysiological and behavioral evidence has shown that these receptors play a role in modulating pacemaker activity and feeding behavior. Here, we present our genomic analysis that revealed hydra proteins having strong homology with the strychnine-binding region of the human receptor protein, GlyRα1. We further present immunocytochemical evidence for the specific labeling of cell and tissue preparations of hydra by a commercially available polyclonal anti-GlyRα1 antibody, selected through our genomic analysis. Tissue pieces and cell macerates from the upper and lower thirds of the body and ablated tentacles were double-labeled with this antibody and with an antibody specific for α-tubulin, to identify the glycine receptors and microtubules, respectively. Extensive receptor labeling was evident on the membranes, cell bodies and myonemes of endodermal and ectodermal epithelial cells, cell bodies and neurites of nerve cells, cnidocytes and interstitial cells. Labeling of the membranes of epithelial cells frequently corresponded to conspicuous varicosities (presumptive presynaptic sites) in the associated nerve net. Our findings support the idea that glycine receptors form an integral part of the nerve and effector systems that control hydra behavior.

Effect of carotid sympathetic nerve net stripping operation in treating children patients with spastic unilateral cerebral palsy and its effect on motor function / 重庆医学

Objective To investigate the effect of carotid sympathetic nerve net stripping operation in treating children patients with spastic unilateral cerebral palsy and its effect on motor function.Methods Seventy-six children cases of spastic unilateral cerebral palsy were divided into the control group and observation group.On the basis of routine therapy,the former was treated with type A botulinum toxin,while the latter used the carotid sympathetic nerve netting operation for the treatment.After 6-month treatment,the improvement degree of the Comprehensive Functional Rating Scale of Cerebral Palsy Children,Gross Motor Function Measure(GMFM) score and Ashworth spasm grade were compared between the two groups.Results after 6-month treatment,the improvement degrees of the Comprehensive Functional Rating Scale of Cerebral Palsy Children,GMFM scores and Ashworth spasm grade in the observation group were significantly greater than those in the control group,the difference was statistically significant (P＜0.05).Conclusion The carotid sympathetic nerve net stripping operation in treating children patients with spastic unilateral cerebral palsy has significant effect and is worthy to be popularized in clinic.

Characterization of NvLWamide-like neurons reveals stereotypy in Nematostella nerve net development.

The organization of cnidarian nerve nets is traditionally described as diffuse with randomly arranged neurites that show minimal reproducibility between animals. However, most observations of nerve nets are conducted using cross-reactive antibodies that broadly label neurons, which potentially masks stereotyped patterns produced by individual neuronal subtypes. Additionally, many cnidarians species have overt structures such as a nerve ring, suggesting higher levels of organization and stereotypy exist, but mechanisms that generated that stereotypy are unknown. We previously demonstrated that NvLWamide-like is expressed in a small subset of the Nematostella nerve net and speculated that observing a few neurons within the developing nerve net would provide a better indication of potential stereotypy. Here we document NvLWamide-like expression more systematically. NvLWamide-like is initially expressed in the typical neurogenic salt and pepper pattern within the ectoderm at the gastrula stage, and expression expands to include endodermal salt and pepper expression at the planula larval stage. Expression persists in both ectoderm and endoderm in adults. We characterized our NvLWamide-like::mCherry transgenic reporter line to visualize neural architecture and found that NvLWamide-like is expressed in six neural subtypes identifiable by neural morphology and location. Upon completing development the numbers of neurons in each neural subtype are minimally variable between animals and the projection patterns of each subtype are consistent. Furthermore, between the juvenile polyp and adult stages the number of neurons for each subtype increases. We conclude that development of the Nematostella nerve net is stereotyped between individuals. Our data also imply that one aspect of generating adult cnidarian nervous systems is to modify the basic structural architecture generated in the juvenile by increasing neural number proportionally with size.

[Research advances on cortical functional and structural deficits of amblyopia].

Previous studies have observed functional deficits in primary visual cortex. With the development of functional magnetic resonance imaging and electrophysiological technique, the research of the striate, extra-striate cortex and higher-order cortical deficit underlying amblyopia reaches a new stage. The neural mechanisms of amblyopia show that anomalous responses exist throughout the visual processing hierarchy, including the functional and structural abnormalities. This review aims to summarize the current knowledge about structural and functional deficits of brain regions associated with amblyopia. (Chin J Ophthalmol, 2017, 53: 392-395).

Non-overlapping Neural Networks in Hydra vulgaris.

To understand the emergent properties of neural circuits, it would be ideal to record the activity of every neuron in a behaving animal and decode how it relates to behavior. We have achieved this with the cnidarian Hydra vulgaris, using calcium imaging of genetically engineered animals to measure the activity of essentially all of its neurons. Although the nervous system of Hydra is traditionally described as a simple nerve net, we surprisingly find instead a series of functional networks that are anatomically non-overlapping and are associated with specific behaviors. Three major functional networks extend through the entire animal and are activated selectively during longitudinal contractions, elongations in response to light, and radial contractions, whereas an additional network is located near the hypostome and is active during nodding. These results demonstrate the functional sophistication of apparently simple nerve nets, and the potential of Hydra and other basal metazoans as a model system for neural circuit studies.

Role of epileptogenicity index in the epileptogenic zone and network localization / 中华神经科杂志

Objective To propose a novel stereo-electroencephalography(SEEG) quantitative measure analyzing ictal high frequency (60-90 Hz) and calculating high frequency epileptogenicity index (HFEI) to localize epileptogenic zone and evaluate epileptogenic network. Methods The clinical presurgical evaluation and SEEG data of 15 patients who were performed SEEG electrodes implantation from April 2015 to March 2016 were analyzed retrospectively. Post-implantation head CT images and 3D MRI data were fused for accurately identifying and locating each electrode contact. Ictal SEEG quantitative measure HFEI was calculated and threshold was set. The epileptogenic network was divided into focal, regional, multiple regional and bilateral ones and the results were compared with the pathological results.Results The epileptogenic network was focal for four patients, regional for four patients, multiple regional for six patients and bilateral for one patient (7/15). In terms of the pathology,two cases with hippocampal sclerosis both showed regional network. In four cases with cerebral malacia, two cases showed multiple regional network and the other two cases showed focal network. In six cases with cortical malformation, three cases showed multiple regional network, the other three cases showed focal, regional and bilateral networks respectively. Conclusions We explored a novel SEEG quantitative measure based on the high frequency power analysis,which is objective and could localize epileptogenic zone and evaluate the epileptic network.

Combined 18F-FDG-PET and diffusion tensor imaging in mesial temporal lobe epilepsy with hippocampal sclerosis.

OBJECTIVES: Several studies using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) or diffusion tensor imaging (DTI) have found both temporal and extratemporal abnormalities in patients with mesial temporal lobe epilepsy with ipsilateral hippocampal sclerosis (MTLE-HS), but data are lacking about the findings of both techniques in the same patients. We aimed to determine whether the extent of 18F-FDG-PET hypometabolism is related to DTI abnormalities. METHODS: Twenty-one patients with MTLE-HS underwent comprehensive preoperative evaluation; 18 (86%) of these underwent epilepsy surgery. We analyzed and compared the pattern of white matter (WM) alterations on DTI and cortical hypometabolism on 18F-FDG-PET. RESULTS: We found widespread temporal and extratemporal 18F-FDG-PET and DTI abnormalities. Patterns of WM abnormalities and cortical glucose hypometabolism involved similar brain regions, being more extensive in the left than the right MTLE-HS. We classified patients into three groups according to temporal 18F-FDG-PET patterns: hypometabolism restricted to the anterior third (n = 7), hypometabolism extending to the middle third (n = 7), and hypometabolism extending to the posterior third (n = 7). Patients with anterior temporal hypometabolism showed DTI abnormalities in anterior association and commissural tracts while patients with posterior hypometabolism showed WM alterations in anterior and posterior tracts. CONCLUSIONS: Patients with MTLE-HS have widespread metabolic and microstructural abnormalities that involve similar regions. The distribution patterns of these gray and white matter abnormalities differ between patients with left or right MTLE, but also with the extent of the 18F-FDG-PET hypometabolism along the epileptogenic temporal lobe. These findings suggest a variable network involvement among patients with MTLE-HS.