Objective To explore the role of the prefrontal cortex in semantic encoding of unrelated word pairs by using functional near-infrared spectroscopy (fNIRS). Method Forty-eight subjects were presented unrelated pairs of Chinese words under both the nonsemantic and semantic encoding conditions. Under the nonsemantic condition, subjects judged whether the two words had similar orthographic structures; under the semantic condition, they generated a sentence involving the presented word pairs. The changes of regional blood volume associated with the cognitive tasks were measured by using fNIRS equipment which was a continuous optical imager. Result The regions that corresponded to the prefrontal regions showed greater activation under semantic than nonsemantic condition in both left and right hemispheres, although the extent of the activation was larger in the left than right prefrontal regions. This result was consistent with other neuroimaging studies on unrelated word pairs processing, but did not conform to the strict interpretations of the hemispheric encoding/retrieval asymmetry model (HERA). Conclusion This study suggests that material specificity is one of the important factors to influence hemispheric asymmetry in memory encoding. When associations between items are required, right prefrontal regions participate in the encoding processing as well. It also indicates that fNIRS imaging is a viable method of investigating higher level cognitive processing such as memory.

The perception of motion is an important function of vision. Neural wiring diagrams for extracting directional information have been obtained by connectome reconstruction. Direction selectivity in Drosophila is thought to originate in T4/T5 neurons through integrating inputs with different temporal filtering properties. Through genetic screening based on synaptic distribution, we isolated a new type of TmY neuron, termed TmY-ds, that form reciprocal synaptic connections with T4/T5 neurons. Its neurites responded to grating motion along the four cardinal directions and showed a variety of direction selectivity. Intriguingly, its direction selectivity originated from temporal filtering neurons rather than T4/T5. Genetic silencing and activation experiments showed that TmY-ds neurons are functionally upstream of T4/T5. Our results suggest that direction selectivity is generated in a tripartite circuit formed among these three neurons-temporal filtering, TmY-ds, and T4/T5 neurons, in which TmY-ds plays a role in the enhancement of direction selectivity in T4/T5 neurons.
Animals ; Neurites ; Drosophila ; Neurons ; Connectome

The caudal forelimb area (CFA) of the mouse cortex is essential in many forelimb movements, and diverse types of GABAergic interneuron in the CFA are distinct in the mediation of cortical inhibition in motor information processing. However, their long-range inputs remain unclear. In the present study, we combined the monosynaptic rabies virus system with Cre driver mouse lines to generate a whole-brain map of the inputs to three major inhibitory interneuron types in the CFA. We discovered that each type was innervated by the same upstream areas, but there were quantitative differences in the inputs from the cortex, thalamus, and pallidum. Comparing the locations of the interneurons in two sub-regions of the CFA, we discovered that their long-range inputs were remarkably different in distribution and proportion. This whole-brain mapping indicates the existence of parallel pathway organization in the forelimb subnetwork and provides insight into the inhibitory processes in forelimb movement to reveal the structural architecture underlying the functions of the CFA.

A 3D model of heart configurations and interior structures has been constructed using Visual C++ visualization toolkit based on the Dataset of Visible Chinese Human. The finite element model of left ventricular is obtained from the heart structure model. Both ventricular wall and blood in the cavity are modeled by finite element mesh. The fluid-structure coupling of the left ventricle and blood has been constructed using an arbitrary Lagrange-Euler algorithm. Based on these models, the fluid-structure interaction of the left ventricle and blood in the filling phase is simulated. The simulation result successfully reproduced the biphasic filling flow consisting of early rapid filling and atrial contraction, which is similar to the clinical observation. This study provides a feasible method with which we can use image-based fluid-structure simulation to analyse the structure and haemodynamics properties of heart. It could be applied in heart functional investigations and clinical applications.
Algorithms ; Computer Simulation ; Finite Element Analysis ; Heart ; physiology ; Heart Ventricles ; anatomy & histology ; Hemodynamics ; Humans ; Imaging, Three-Dimensional ; Models, Cardiovascular

Caspases play important roles in cell apoptosis. Measurement of the dynamics of caspase activation in tumor cells not only facilitates understanding of the molecular mechanisms of apoptosis but also contributes to the development, screening, and evaluation of anticancer drugs that target apoptotic pathways. The fluorescence resonance energy transfer (FRET) technique provides a valuable approach for defining the dynamics of apoptosis with high spatio-temporal resolution. However, FRET generally functions in the single-cell level and becomes ineffective when applied in the high throughput detection of caspase activation. In the current study, a FRET sensor was combined with capillary electrophoresis (CE) to achieve a high throughput method for cellular caspase detection. The FRET-based CE system is composed of a homemade CE system and a laser source for detecting the dynamics of caspase-3 in various cells expressing sensors of caspase-3 that have been treated with anticancer drugs, such as cell cycle-independent drug cisplatin and specific cell cycle drugs camptothecin and etoposide, as well as their combination with tumor necrosis factor (TNF). A positive correlation between the caspase-3 activation velocity and drug concentration was observed when the cells were treated with cisplatin, but cells induced by camptothecin and etoposide did not show any apparent correlation with their concentrations. Moreover, different types of cells presented distinct sensitivities under the same drug treatment, and the combination treatment of TNF and anticancer drugs significantly accelerated the caspase-3 activation process. Its high throughput capability and detection sensitivity make the FRET-based CE system a useful tool for investigating the mechanisms of anticancer drugs and anticancer drug screening.
Antineoplastic Agents ; pharmacology ; Camptothecin ; pharmacology ; Caspase 3 ; metabolism ; Cisplatin ; pharmacology ; Drug Screening Assays, Antitumor ; Electrophoresis, Capillary ; methods ; Enzyme Activation ; drug effects ; Etoposide ; pharmacology ; HeLa Cells ; Hep G2 Cells ; Humans ; Neoplasms ; enzymology ; pathology ; Time Factors ; Tumor Necrosis Factor-alpha ; pharmacology

Neurons in the primary auditory area (AUDp) innervate multiple brain regions with long-range projections while receiving informative inputs for diverse functions. However, the brain-wide connections of these neurons have not been comprehensively investigated. Here, we simultaneously applied virus-based anterograde and retrograde tracing, labeled the connections of excitatory and inhibitory neurons in the mouse AUDp, and acquired whole-brain information using a dual-channel fluorescence micro-optical sectioning tomography system. Quantified results showed that the two types of neurons received inputs with similar patterns but sent heterogeneous projections to downstream regions. In the isocortex, functionally different areas consistently sent feedback-dominated projections to these neurons, with concomitant laterally-dominated projections from the sensory and limbic cortices to inhibitory neurons. In subcortical regions, the dorsal and medial parts of the non-lemniscal auditory thalamus (AT) were reciprocally connected to the AUDp, while the ventral part contained the most fibers of passage from the excitatory neurons and barely sent projections back, indicating the regional heterogeneity of the AUDp-AT circuit. Our results reveal details of the whole-brain network and provide new insights for further physiological and functional studies of the AUDp.

The zona incerta (ZI) is involved in various functions and may serve as an integrative node of the circuits for global behavioral modulation. However, the long-range connectivity of different sectors in the mouse ZI has not been comprehensively mapped. Here, we obtained whole-brain images of the input and output connections via fluorescence micro-optical sectioning tomography and viral tracing. The principal regions in the input-output circuits of ZI GABAergic neurons were topologically organized. The 3D distribution of cortical inputs showed rostro-caudal correspondence with different ZI sectors, while the projection fibers from ZI sectors were longitudinally organized in the superior colliculus. Clustering results show that the medial and lateral ZI are two different major functional compartments, and they can be further divided into more subdomains based on projection and input connectivity. This study provides a comprehensive anatomical foundation for understanding how the ZI is involved in integrating different information, conveying motivational states, and modulating global behaviors.
Animals ; Mice ; Zona Incerta ; GABAergic Neurons ; Connectome

The orbitofrontal cortex (OFC) is involved in diverse brain functions via its extensive projections to multiple target regions. There is a growing understanding of the overall outputs of the OFC at the population level, but reports of the projection patterns of individual OFC neurons across different cortical layers remain rare. Here, by combining neuronal sparse and bright labeling with a whole-brain florescence imaging system (fMOST), we obtained an uninterrupted three-dimensional whole-brain dataset and achieved the full morphological reconstruction of 25 OFC pyramidal neurons. We compared the whole-brain projection targets of these individual OFC neurons in different cortical layers as well as in the same cortical layer. We found cortical layer-dependent projections characterized by divergent patterns for information delivery. Our study not only provides a structural basis for understanding the principles of laminar organizations in the OFC, but also provides clues for future functional and behavioral studies on OFC pyramidal neurons.