Fear, a negative emotion triggered by dangerous stimuli, can lead to psychiatric disorders such as phobias, anxiety disorders, and depression. Investigating the neural circuitry underlying congenital fear can offer insights into the pathophysiological mechanisms of related psychiatric conditions. Research on innate fear primarily centers on the response mechanisms to various sensory signals, including olfactory, visual and auditory stimuli. Different types of fear signal inputs are regulated by distinct neural circuits. The neural circuits of the main and accessory olfactory systems receive and process olfactory stimuli, mediating defensive responses like freezing. Escape behaviors elicited by visual stimuli are primarily regulated through the superior colliculus and hypothalamic projection circuits. Auditory stimuli-induced responses, including escape, are mainly mediated through auditory cortex projection circuits. In this article, we review the research progress on neural circuits of innate fear defensive behaviors in animals. We further discuss the different sensory systems, especially the projection circuits of olfactory, visual and auditory systems, to provide references for the mechanistic study of related mental disorders.
Animals ; Humans ; Fear/physiology* ; Nerve Net

Neural oscillatory phenomenon generally exists in the nervous system through a dynamic form. It plays a very important role in the brain, especially in the higher cognitive activities, such as information processing, transfer and integration, consolidating memory and so on. Furthermore, the specific activity pattern of neural oscillations is often associated with cognitive functions and their alterations. Accordingly, how to quantitatively analyze the pattern of neural oscillations becomes one of the fundamental issues in the computational neuroscience. In this review, we addressed a variety of analytic algorithms, which are commonly employed in our recent studies to investigate the issues of neurobiology and cognitive science. In addition, we tried to classify these analytic algorithms by distinguishing their different metrics, synchronization and coupling modes. Finally, multidimensional analytic algorithms for potential application have also been discussed.
Brain ; physiology ; Cognition ; Humans ; Memory ; Nerve Net ; physiology

To explore the self-organization robustness of the biological neural network, and thus to provide new ideas and methods for the electromagnetic bionic protection, we studied both the information transmission mechanism of neural network and spike timing-dependent plasticity (STDP) mechanism, and then investigated the relationship between synaptic plastic and adaptive characteristic of biology. Then a feedforward neural network with the Izhikevich model and the STDP mechanism was constructed, and the adaptive robust capacity of the network was analyzed. Simulation results showed that the neural network based on STDP mechanism had good rubustness capacity, and this characteristics is closely related to the STDP mechanisms. Based on this simulation work, the cell circuit with neurons and synaptic circuit which can simulate the information processing mechanisms of biological nervous system will be further built, then the electronic circuits with adaptive robustness will be designed based on the cell circuit.
Action Potentials ; Models, Neurological ; Nerve Net ; Neuronal Plasticity ; Neurons

In this study, the automatic segmentation of the irregular lesion region in the image of fundus fluorescence angiography was actualized by means of the modified Back Propagation (BP) neural network method. Combining the transfer scaling coefficient between pixel of the image and the actual size, the area of the irregular lesion region was measured. The results may provide valuable data for the clinical diagnosis, treatment and prognostic evaluation.
Algorithms ; Fluorescein Angiography ; methods ; Nerve Net ; Retinal Diseases ; diagnosis ; pathology

In contrast to the spinal control of erection, relatively little is known about the brain control. In the present review, we have outlined the role of brain structures involved in penile erection and provided a synopsis on the brain circuit of erection. Findings from both animal and human studies are discussed. Evidence suggests that the most important structures are the frontal lobe, cingulate gyrus, amygdala, thalamus and hypothalamus. Within the brain circuit of erection, the thalamus serves as a gate-controller in which all relevant information is evaluated and further processed to higher and lower centres.
Brain ; physiology ; Humans ; Male ; Models, Neurological ; Nerve Net ; Penile Erection ; Thalamus ; physiology

Dementia ; pathology ; Hallucinations ; pathology ; Humans ; Lewy Body Disease ; pathology ; Nerve Net ; pathology

Animals ; Behavior, Animal ; physiology ; Drosophila melanogaster ; physiology ; Female ; Instinct ; Male ; Nerve Net ; physiology ; Neurons ; physiology

BACKGROUNDPrevious studies have demonstrated that acupuncture could modulate various brain systems in the resting brain networks. Graph theoretical analysis offers a novel way to investigate the functional organization of the large-scale cortical networks modulated by acupuncture at whole brain level. In this study, we used wavelets correlation analysis to estimate the pairwise correlations between 90 cortical and subcortical human brain regions in normal human volunteers scanned during the post-stimulus resting state.

METHODSThirty-two college students, all right-handed and acupuncture naïve, participated in this study. Every participant received only one acupoint stimulation, resulting in 16 subjects in one group. Both structural functional magnetic resonance imaging (fMRI) data (3D sequence with a voxel size of 1 mm(3) for anatomical localization) and functional fMRI data (TR = 1500 ms, TE = 30 ms, flip angle = 90°) were collected for each subject. After thresholding the resulting scale-specific wavelet correlation matrices to generate undirected binary graphs, we compared graph metrics of brain organization following verum manual acupuncture (ACU) and sham acupuncture (SHAM) groups.

RESULTSThe topological parameters of the large-scale brain networks in ACU group were different from those of the SHAM group at multiple scales. There existed distinct modularity functional brain networks during the post-stimulus resting state following ACU and SHAM at multiple scales.

CONCLUSIONSThe distinct modulation patterns of the resting brain attributed to the specific effects evoked by acupuncture. In addition, we also identified that there existed frequency-specific modulation in the post-stimulus resting brain following ACU and SHAM. The modulation may be related to the effects of verum acupuncture on modulating special disorder treatment. This preliminary finding may provide a new clue to understand the relatively function-oriented specificity of acupuncture effects.

Acupuncture Points ; Acupuncture Therapy ; Adult ; Analgesia ; Brain ; physiology ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Nerve Net

In 1905, Henry Head first suggested that transmission of pain-related protopathic information can be negatively modulated by inputs from afferents sensing innocuous touch and temperature. In 1965, Melzak and Wall proposed a more concrete gate control theory of pain that highlights the interaction between unmyelinated C fibers and myelinated A fibers in pain transmission. Here we review the current understanding of the spinal microcircuits transmitting and gating mechanical pain or itch. We also discuss how disruption of the gate control could cause pain or itch evoked by innocuous mechanical stimuli, a hallmark symptom for many chronic pain or itch patients.
Animals ; Humans ; Nerve Net ; pathology ; physiopathology ; Pain ; pathology ; Pruritus ; pathology ; Spinal Cord ; pathology ; Synaptic Transmission ; physiology

Connectome/methods* ; Magnetic Resonance Imaging/methods* ; Brain/diagnostic imaging* ; Head ; Brain Mapping/methods* ; Nerve Net