Neural mechanisms of feature binding

An object is usually composed of different features(e.g.,color,orientation,and motion),which are processed by segregated visual pathways and represented by functionally specialized brain areas.However,we perceive an object as a coherent whole,rather than its isolated features.How we integrate those isolated features and achieve a precise perception of objects is a fundamental challenge for the visual system,which is referred to as the binding problem.

A Review of fMRI Investigations into the Neural Mechanisms of Metaphor Comprehension

The availability of functional magnetic resonance imaging （fMRI） has revolutionized the study of language, especially figurative language such as metaphor comprehension. The last decade has witnessed considerable research on the neural mechanisms of metaphor comprehension at word, sentence, and discourse levels respectively. This paper offers a general review of fMRI investigations into the neural networks involved in metaphor processing to date. First we introduce how metaphor studies can be done by means of fMRI technique at word, sentence and discourse levels. Then we discuss several confounding factors such as familiarity, and task demand and difficulty, which may lead to inconsistent results in fMRI experiments. Finally, we try to propose some constructive suggestions for further research in this field.

Neural Mechanisms of Trace in Chinese Topicalized Constructions

Trace theory is a very important linguistic hypothesis within the framework of Generative Grammar. But whether the theory is correct, namely whether the assumed empty trace exists in syntactic representation, must be verified by experiments concerning the neural mechanisms of language. On the basis of Generative Grammar, the current study uses event- related potentials （ERP） to examine the neural mechanism of trace in Chinese topicalized constructions. The results show that three types of waves （a sustained negativity, a negativity elicited by the verb and a P600 elicited at the sentence-final position） are observed in the processing of Chinese topicalized constructions. These neural electrophysiological indexes indicate that the sentence-initial topic does leave a trace in the position out of which it moves, i.e. the sentence-final position, suggesting that there is a syntactic dependency between the topic and its trace. Consequently, we draw the conclusion that trace is neurologically supported in Chinese topicalized constructions and trace theory isneurophysiologically viable. Meanwhile, the study also adds neural evidence to the view that Chinese topicalized constructions are structures derived from syntactic movement.

Analysis of fluoxetine-induced plasticity mechanisms as a strategy for understanding plasticity related neural disorders

Fluoxetine hydrochloride,better known for its commercial name Prozac,is one of the most widely prescribed antidepressant drugs all over the world.This drug was considered a＂breakthrough drug＂for the treatment of depression because of its very high selectivity as a serotonin reuptake inhibitor and because it presented a lower side-effectprofile than previous drugs （Wong et al., 2005）.

Neural mechanism of proposer's decision-making in the ultimatum and dictator games

Previous studies have demonstrated that reactions to unfair offers in the ultimatum game are correlated with negative emotion. However, little is known about the difference in neural activity between a proposer＇s decision-making in the ultimatum game compared with the dictator game. The present functional magnetic resonance imaging study revealed that proposing fair offers in the dictator game elicited greater activation in the right supramarginal gyrus, right medial frontal gyrus and left anterior cingulate cortex compared with proposing fair offers in the ultimatum game in 23 Chinese undergraduate and graduate students from Beijing Normal University in China. However, greater activation was found in the right superior temporal gyrus and left cingulate gyrus for the reverse contrast. ＂The results indicate that proposing fair offers in the dictator game is more strongly associated with cognitive control and conflicting information processing compared with proposing fair offers in the ultimatum game.

Streptozotocin induced Alzheimer's disease like changes and the underlying neural degeneration and regeneration mechanism

Alzheimer’s disease（AD）is a neurodegenerative disorder which is remarkably characterized by pathological hallmarks that include neurofibrillary tangles,neuronal loss extracellular senile plaques containing aggregated amyloid beta（Aβ）,and neurofibrillary tangles composed of the hyperphosphorylated form of the microtubule protein tau.It is the most common form of dementia which is characterized by severe neurodegenerative changes such as loss of neurons and synapses in brain（Kamat et al.,2014）.

Neural-mechanism-driven image block encryption algorithm incorporating a hyperchaotic system and cloud model

An image encryption algorithm is proposed in this paper based on a new four-dimensional hyperchaotic system,a neural mechanism,a Galois field and an improved Feistel block structure,which improves the efficiency and enhances the security of the encryption algorithm.Firstly,a four-dimensional hyperchaotic system with a large key space and chaotic dynamics performance is proposed and combined with a cloud model,in which a more complex and random sequence is constructed as the key stream,and the problem of chaotic periodicity is solved.Then,the key stream is combined with the neural mechanism,Galois field and improved Feistel block structure to scramble and diffuse the image encryption.Finally,the experimental results and security analysis show that the encryption algorithm has a good encryption effect and high encryption efficiency,is secure,and can meet the requirements of practical applications.

Facial Expression Recognition Using Enhanced Convolution Neural Network with Attention Mechanism

Facial Expression Recognition(FER)has been an interesting area of research in places where there is human-computer interaction.Human psychol-ogy,emotions and behaviors can be analyzed in FER.Classifiers used in FER have been perfect on normal faces but have been found to be constrained in occluded faces.Recently,Deep Learning Techniques(DLT)have gained popular-ity in applications of real-world problems including recognition of human emo-tions.The human face reflects emotional states and human intentions.An expression is the most natural and powerful way of communicating non-verbally.Systems which form communications between the two are termed Human Machine Interaction(HMI)systems.FER can improve HMI systems as human expressions convey useful information to an observer.This paper proposes a FER scheme called EECNN(Enhanced Convolution Neural Network with Atten-tion mechanism)to recognize seven types of human emotions with satisfying results in its experiments.Proposed EECNN achieved 89.8%accuracy in classi-fying the images.

Diffusion tensor tractography studies on mechanisms of recovery of injured fornix

The fornix,which connects the medial temporal lobe and the medial diencephalon,is involved in episodic memory as an important part of the Papez circuit.The mechanisms of recovery of an injured fornix revealed by diffusion tensor tractography in the five studies are summarized as follows：1） recovery through the nerve tract from an injured fornical crus to the medial temporal lobe via the normal pathway of the fornical crus;2）recovery through the nerve tract originating from an ipsi-lesional fornical body connected to the ipsi-lesional medial temporal lobe via the splenium of the corpus callosum;3） recovery through the nerve tract from the ipsi-lesional fornical body extending to the contra-lesional medial temporal lobe via the splenium of the corpus callosum;4） recovery through the nerve tract originating from the ipsi-lesional fornical column connected to the ipsi-lesional medial temporal lobe;and 5） recovery through the nerve tract originating from the contra-lesional fornical column connected to the ipsi-lesional medial temporal lobe via the contra-lesional medial temporal lobe and the splenium of the corpus callosum.These diffusion tensor tractography studies on mechanisms of recovery of injured fornical crus appeared to provide useful information for clinicians caring for patients with brain injury,however,studies on this topic are still in the beginning stages.

Visual cognition of birds and its underlying neural mechanism:A review

Birds have acute vision and many remarkable visual cognition abilities,due to their unique living environment.The underlying neural mechanisms have also attracted interests of researchers in neuroscience.Here,we firstly summarize the visual cognition abilities of birds,and make a comparison with mammals.Secondly,the underlying neural mechanisms are presented,including histological structure of avian brain and visual pathways,typical experimental results and conclusions in electrochemistry and electrophysiology.The latter mainly focuses on several higher brain areas related to visual cognition,including mesopallium ventrolaterale,entopallium,visual Wulst,and nidopallium caudolaterale.Finally,we make a conclusion and provide a suggestion about future studies on revealing the neural mechanisms of avian visual cognition.This review presents a detailed understanding of avian visual cognition and would be helpful in ornithology studies in the field of cognitive neuroscience.

Neural Mechanism Underlying Task-Specific Enhancement of Motor Learning by Concurrent Transcranial Direct Current Stimulation

The optimal protocol for neuromodulation by transcranial direct current stimulation(tDCS)remains unclear.Using the rotarod paradigm,we found that mouse motor learning was enhanced by anodal tDCS(3.2 mA/cm^(2))during but not before or after the performance of a task.Dual-task experiments showed that motor learning enhancement was specific to the task accompanied by anodal tDCS.Studies using a mouse model of stroke induced by middle cerebral artery occlusion showed that concurrent anodal tDCS restored motor learning capability in a task-specific manner.Transcranial in vivo Ca^(2+)imaging further showed that anodal tDCS elevated and cathodal tDCS suppressed neuronal activity in the primary motor cortex(M1).Anodal tDCS specifically promoted the activity of task-related M1 neurons during task performance,suggesting that elevated Hebbian synaptic potentiation in task-activated circuits accounts for the motor learning enhancement.Thus,application of tDCS concurrent with the targeted behavioral dysfunction could be an effective approach to treating brain disorders.

Cardiac Remote Conditioning and Clinical Relevance:All Together Now!

Acute myocardial infarction （AMI） is the leading cause of death and disability worldwide. Timely reperfusion is the standard of care and results in decreased infarct size, improving patient survival and prognosis. However, 25% of patients proceed to develop heart failure （HF） after myocardial infarction （MI） and 50% of these will die within five years. Since the size of the infarct is the major predictor of the outcome, including the development of HF, therapies to improve myocardial salvage have great potential. Over the past three decades, a number of stimuli have been discovered that activate endogenous cardioprotective pathways. In ischemic preconditioning （IPC） and ischemic postconditioning, ischemia within the heart initiates the protection. Brief reversible episodes of ischemia in vascular beds remote from the heart can also trigger cardioprotection when applied before, during, or immediately after myocardial ischemia-- known as remote ischemic pre-, per-, and post-conditioning, respectively. Although the mechanism of remote ischemic preconditioning （RIPC） has not yet been fully elucidated, many mechanistic components are shared with IPC. The discovery of RIPC led to research into the use of remote non-ischemic stimuli including nerve stimulation （spinal and vagal）, and electroacupuncture （EA）. We discovered and, with others, have elucidated mechanistic aspects of a non- ischemic phenomenon we termed remote preconditioning of trauma （RPCT）. RPCT operates via neural stimulation of skin sensory nerves and has similarities and differences to nerve stimulation and EA conducted at acupoints. We show herein that RPCT can be mimicked using electrical stimulation of the abdominal midline （EA-like treatment） and that this modality of activating cardioprotection is powerful as both a preconditioning and a postconditioning stimulus （when applied at reperfusion）. Investigations of these cardioprotective phenomena have led to a more integrative understanding of mechanisms related to cardioprotection, and in the last five to ten years, it has become clear that the mechanisms are similar, whether induced by ischemic or non-ischemic stimuli. Taking together much of the data in the literature, we propose that all of these cardioprotective ＂conditioning＂ phenomena represent activation from different entry points of a cardiac conditioning network that converges upon specific mediators and effectors of myocardial cell survival, including NF-KB, Stat3/5, protein kinase C, bradykinin, and the mitoKA^P channel. Nervous system pathways may represent a novel mechanism for initiating conditioning of the heart and other organs. IPC and RIPC have proven difficult to translate clinically, as they have associated risks and cannot be used in some patients. Because of this, the use of neural and nociceptive stimuli is emerging as a potential non-ischemic and non-traumatic means to initiate cardiac conditioning. Clinical relevance is underscored by the demonstration of postconditioning with one of these modalities, supporting the conclusion that the development of pharmaceuticals and electroceuticals for this purpose is an area ripe for clinical development.

Bio-Inspired Controller for a Robot Cheetah with a Neural Mechanism Controlling Leg Muscles

The realization of a high-speed running robot is one of the most challenging problems in developing legged robots. The excellent performance of cheetahs provides inspiration for the control and mechanical design of such robots. This paper presents a three-dimensional model of a cheetah that predicts the locomotory behaviors of a running cheetah. Applying biological knowledge of the neural mechanism, we control the muscle flexion and extension during the stance phase, and control the positions of the joints in the flight phase via a PD controller to minimize complexity. The proposed control strategy is shown to achieve similar locomotion of a real cheetah. The simulation realizes good biological properties, such as the leg retraction, ground reaction force, and spring-like leg behavior. The stable bounding results show the promise of the controller in high-speed locomotion. The model can reach 2.7 m-s^-1 as the highest speed, and can accelerate from 0 to 1.5 m-s^-1 in one stride cycle. A mechanical structure based on this simulation is designed to demonstrate the control approach, and the most recently developed hindlimb controlled by the proposed controller is presented in swinging-leg experiments and jump-force experiments.

Neural Mechanism and Representation of English and Chinese Metaphors of Bilinguals with Different Second Language Proficiency: An ERP Study

Brain mechanism of metaphor processing has always been a focus in Neurolinguistics. This study approaches bilinguals＇ metaphor semantic representation mechanism with Chinese bilinguals with different levels of second language proficiency by means of ERP （Event-related Potentials） technology. The experiment results showed that： 1） Both hemispheres collaborate in metaphor processing with the left hemisphere serving a leading semantic recognition role. The left hemisphere is more sensitive to first language input, while the right hemisphere is more active to second language input. 2） Compared with Chinese learners of higher proficiency in L2, learners of lower proficiency tend to adopt more Chinese neural mechanism in processing English metaphors. 3） When learners process metaphors, the neural mechanism difference of learners of higher proficiency is smaller than that of those of lower proficiency. The higher the second language proficiency, the higher the degree of common representation of Chinese and English metaphor.

Neural plasticity in high-level visual cortex underlying object perceptual learning

With intensive training, human can achieve impressive behavioral improvement on various perceptual tasks. This phenomenon, termed perceptual learning, has long been considered as a hallmark of the plasticity of sensory neural system. Not surprisingly, high-level vision, such as object perception, can also be improved by perceptual learning. Here we review recent psychophysical, electrophysiological, and neuroimaging studies investigating the effects of training on object selective cortex, such as monkey inferior temporal cortex and human lateral occipital area. Evidences show that learning leads to an increase in object selectivity at the single neuron level and/or the neuronal population level. These findings indicate that high-level visual cortex in humans is highly plastic and visual experience can strongly shape neural functions of these areas. At the end of the review, we discuss several important future directions in this area.

Researchers revealed a neural mechanism underlying body temperature regulation

Subject Code:C09 With the support by the National Natural Science Foundation of China,a research group led by Dr.Shen Wei(沈伟)from Shanghai Tech University has deconstructed a neural circuit for body temperature regulation,which was published in PNAS(2017,114:2042—2047).

延髓头端腹外侧区在电针预处理减轻心肌缺血再灌注损伤中的作用

ObjectiveTo observe the effects of pretreatment with electroacupuncture (EA) on neuron activity in the rostral ventrolateral medulla (RVLM) of rats with myocardial ischemia-reperfusion injury (MIRI) and explore the central regulatory mechanism of EA in attenuating MIRI.MethodsOf 72 SD rats, 12 were randomly allocated into the group of EA pretreatment + RVLM nucleus damage (EA + RVLM lesion group). The other 60 rats were randomized (20 rats each) into a sham-operation group, a model group, and an EA pretreatment group (EA group). Except for the rats in the sham-operation group, the models of MIRI were prepared by ligating the left anterior descending coronary artery in the model, EA, and EA + RVLM lesion groups. The rats of the EA group were intervened with EA at “Shénmén (神门HT7)” and “Tōnglĭ (通里HT5)”, 1 mA in current intensity and 2 Hz in frequency, for 20 min each time per day. Before modeling, the intervention was given for seven consecutive days. In the EA + RVLM lesion group, 3 weeks after microinjection with the neuronal apoptotic virus at bilateral RVLM, the same EA intervention as the EA group was provided. Afterward, the MIRI models were prepared. In the model group, no EA intervention was given. Using Powerlab electrophysiolograph, ST segment displacement value and arrhythmia score were recorded and analyzed before modeling, 30 min after ligation, and 120 min after reperfusion in each group. The concentration of cardiac troponin (cTnl) was detected with an ELISA assay kit. Using immunofluorescence staining, the expression level of c-fos protein of RVLM was detected in the sham-operation, model, and EA groups separately. Plexon multichannel acquisition processor was adopted to record the neuronal firing and field potential of RVLM in the sham-operation, model, and EA groups.ResultsST segment displacement value, arrhythmia score, and cTnl concentration 30 min after ligation and 120 min after reperfusion were all elevated in the model group compared to the sham-operation group (all P < 0.01). ST segment displacement value, arrhythmia score, and cTnl concentration were lower in the EA group compared to the model and EA + RVLM lesion groups (P < 0.01). Compared with the sham-operation group, the expression level of c-fos and the total firing frequency in RVLM were significantly higher in the model group (P < 0.01). However, the expression level of c-fos and the total firing frequency in RVLM were lower in the EA group compared with the model group (P < 0.01).ConclusionElectroacupuncture pretreatment may induce changes in c-fos protein expression and neuronal activity in RVLM to mitigate myocardial lesions. RVLM plays an important role in electroacupuncture pretreatment for alleviating MIRI.

Unique Pharmacology,Brain Dysfunction,and Therapeutic Advancements for Fentanyl Misuse and Abuse

Fentanyl is a fully synthetic opioid with analgesic and anesthetic properties.It has become a primary driver of the deadliest opioid crisis in the United States and elsewhere,consequently imposing devastating social,economic,and health burdens worldwide.However,the neural mechanisms that underlie the behavioral effects of fentanyl and its analogs are largely unknown,and approaches to prevent fentanyl abuse and fentanyl-related overdose deaths are scarce.This review presents the abuse potential and unique pharmacology of fentanyl and elucidates its potential mechanisms of action,including neural circuit dysfunction and neuroinflammation.We discuss recent progress in the development of pharmacological interventions,anti-fentanyl vaccines,anti-fentanyl/heroin conjugate vaccines,and monoclonal antibodies to attenuate fentanyl-seeking and prevent fentanyl-induced respiratory depression.However,translational studies and clinical trials are still lacking.Considering the present opioid crisis,the development of effective pharmacological and immunological strategies to prevent fentanyl abuse and overdose are urgently needed.

An ERP Study on Metaphor Comprehension in the Bilingual Brain

A good number of neurophysiological studies have been conducted to explore the neural mechanisms of metaphor processing, but few have taken the bilingual phenomenon into consideration. The current study, by using event related potentials （ERPs）, investigated the neural mechanism employed by Chinese native speakers whose second language is English in comprehending Chinese and English metaphors. Amplitudes of the N400 ERP component （350-600 ms） were more negative for English metaphors compared with Chinese literal sentences, English literal sentences and Chinese metaphors. In addition, both hemispheres were more activated in processing English metaphors than other conditions. These findings provide electrophysiological evidence for a different mechanism used by Chinese-English bilinguals to comprehend Chinese and English metaphors.

Insular Cortex is Critical for the Perception, Modulation,and Chronification of Pain

An increasing body of neuroimaging and electrophysiological studies of the brain suggest that the insular cortex（IC） integrates multimodal salient information ranging from sensation to cognitive-affective events to create conscious interoception. Especially with regard to pain experience, the IC has been supposed to participate in both sensory-discriminative and affective-motivational aspects of pain. In this review, we discuss the latest data proposing that subregions of the IC are involved in isolated pain networks： the posterior sensory circuit and the anterior emotional network. Due to abundant connections with other brain areas, the IC is likely to serve as an interface where cross-modal shaping of pain occurs. In chronic pain,however, this mode of emotional awareness and the modulation of pain are disrupted. We highlight some of the molecular mechanisms underlying the changes of the pain modulation system that contribute to the transition from acute to chronic pain in the IC.