Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.378
Filtrar
1.
Carbohydr Polym ; 332: 121927, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38431420

RESUMO

Natural bone exhibits a complex anisotropic and micro-nano hierarchical structure, more importantly, bone extracellular matrix (ECM) presents liquid crystal (LC) phase and viscoelastic characteristics, providing a unique microenvironment for guiding cell behavior and regulating osteogenesis. However, in bone tissue engineering scaffolds, the construction of bone-like ECM microenvironment with exquisite microstructure is still a great challenge. Here, we developed a novel polysaccharide LC hydrogel supported 3D printed poly(l-lactide) (PLLA) scaffold with bone-like ECM microenvironment and micro-nano aligned structure. First, we prepared a chitin whisker/chitosan polysaccharide LC precursor, and then infuse it into the pores of 3D printed PLLA scaffold, which was previously surface modified with a polydopamine layer. Next, the LC precursor was chemical cross-linked by genipin to form a hydrogel network with bone-like ECM viscoelasticity and LC phase in the scaffold. Subsequently, we performed directional freeze-casting on the composite scaffold to create oriented channels in the LC hydrogel. Finally, we soaked the composite scaffold in phytic acid to further physical cross-link the LC hydrogel through electrostatic interactions and impart antibacterial effects to the scaffold. The resultant biomimetic scaffold displays osteogenic activity, vascularization ability and antibacterial effect, and is expected to be a promising candidate for bone repair.


Assuntos
Quitosana , Cristais Líquidos , Animais , Quitosana/química , Hidrogéis/farmacologia , Hidrogéis/metabolismo , Quitina/farmacologia , Quitina/metabolismo , Vibrissas , Tecidos Suporte/química , Regeneração Óssea , Engenharia Tecidual , Osteogênese , Matriz Extracelular/metabolismo , Antibacterianos/farmacologia
2.
Sci Rep ; 14(1): 6302, 2024 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-38491035

RESUMO

Multisensory integration is necessary for the animal to survive in the real world. While conventional methods have been extensively used to investigate the multisensory integration process in various brain areas, its long-range interactions remain less explored. In this study, our goal was to investigate interactions between visual and somatosensory networks on a whole-brain scale using 15.2-T BOLD fMRI. We compared unimodal to bimodal BOLD fMRI responses and dissected potential cross-modal pathways with silencing of primary visual cortex (V1) by optogenetic stimulation of local GABAergic neurons. Our data showed that the influence of visual stimulus on whisker activity is higher than the influence of whisker stimulus on visual activity. Optogenetic silencing of V1 revealed that visual information is conveyed to whisker processing via both V1 and non-V1 pathways. The first-order ventral posteromedial thalamic nucleus (VPM) was functionally affected by non-V1 sources, while the higher-order posterior medial thalamic nucleus (POm) was predominantly modulated by V1 but not non-V1 inputs. The primary somatosensory barrel field (S1BF) was influenced by both V1 and non-V1 inputs. These observations provide valuable insights for into the integration of whisker and visual sensory information.


Assuntos
Imageamento por Ressonância Magnética , Tálamo , Camundongos , Animais , Tálamo/fisiologia , Córtex Somatossensorial/diagnóstico por imagem , Córtex Somatossensorial/fisiologia , Vibrissas/fisiologia
3.
Bioinspir Biomim ; 19(3)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38377615

RESUMO

The spanwise undulated cylinder geometry inspired by seal whiskers has been shown to alter shedding frequency and reduce fluid forces significantly compared to smooth cylindrical geometry. Prior research has parameterized the whisker-inspired geometry and demonstrated the relevance of geometric variations on force reduction properties. Among the geometric parameters, undulation wavelength was identified as a significant contributor to forcing changes. To analyze the effect of undulation wavelength, a thorough investigation isolating changes in wavelength is performed to expand upon previous research that parameterized whisker-inspired geometry and the relevance of geometric variations on the force reduction properties. A set of five whisker-inspired models of varying wavelength are computationally simulated at a Reynolds number of 250 and compared with an equivalent aspect ratio smooth elliptical cylinder. Above a critical non-dimensional value, the undulation wavelength reduces the amplitude and frequency of vortex shedding accompanied by a reduction in oscillating lift force. Frequency shedding is tied to the creation of wavelength-dependent vortex structures which vary across the whisker span. These vortices produce distinct shedding modes in which the frequency and phase of downstream structures interact to decrease the oscillating lift forces on the whisker model with particular effectiveness around the wavelength values typically found in nature. The culmination of these location-based modes produces a complex and spanwise-dependent lift frequency spectra at those wavelengths exhibiting maximum force reduction. Understanding the mechanisms of unsteady force reduction and the relationship between undulation wavelength and frequency spectra is critical for the application of this geometry to vibration tuning and passive flow control for vortex-induced vibration (VIV) reduction.


Assuntos
Focas Verdadeiras , Vibrissas , Animais , Vibração
4.
Sci Rep ; 14(1): 4169, 2024 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-38379020

RESUMO

Gephyrin is the main scaffolding protein at inhibitory postsynaptic sites, and its clusters are the signaling hubs where several molecular pathways converge. Post-translational modifications (PTMs) of gephyrin alter GABAA receptor clustering at the synapse, but it is unclear how this affects neuronal activity at the circuit level. We assessed the contribution of gephyrin PTMs to microcircuit activity in the mouse barrel cortex by slice electrophysiology and in vivo two-photon calcium imaging of layer 2/3 (L2/3) pyramidal cells during single-whisker stimulation. Our results suggest that, depending on the type of gephyrin PTM, the neuronal activities of L2/3 pyramidal neurons can be differentially modulated, leading to changes in the size of the neuronal population responding to the single-whisker stimulation. Furthermore, we show that gephyrin PTMs have their preference for selecting synaptic GABAA receptor subunits. Our results identify an important role of gephyrin and GABAergic postsynaptic sites for cortical microcircuit function during sensory stimulation.


Assuntos
Proteínas de Membrana , Receptores de GABA-A , Vibrissas , Animais , Receptores de GABA-A/metabolismo , Vibrissas/metabolismo , Proteínas de Transporte/metabolismo , Células Piramidais/metabolismo , Sinapses/metabolismo
5.
Nat Commun ; 15(1): 1571, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38383567

RESUMO

Astrocytes express ionotropic receptors, including N-methyl-D-aspartate receptors (NMDARs). However, the contribution of NMDARs to astrocyte-neuron interactions, particularly in vivo, has not been elucidated. Here we show that a knockdown approach to selectively reduce NMDARs in mouse cortical astrocytes decreases astrocyte Ca2+ transients evoked by sensory stimulation. Astrocyte NMDAR knockdown also impairs nearby neuronal circuits by elevating spontaneous neuron activity and limiting neuronal recruitment, synchronization, and adaptation during sensory stimulation. Furthermore, this compromises the optimal processing of sensory information since the sensory acuity of the mice is reduced during a whisker-dependent tactile discrimination task. Lastly, we rescue the effects of astrocyte NMDAR knockdown on neurons and improve the tactile acuity of the animal by supplying exogenous ATP. Overall, our findings show that astrocytes can respond to nearby neuronal activity via their NMDAR, and that these receptors are an important component for purinergic signaling that regulate astrocyte-neuron interactions and cortical sensory discrimination in vivo.


Assuntos
Astrócitos , Receptores de N-Metil-D-Aspartato , Camundongos , Animais , Astrócitos/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Vibrissas/metabolismo , Neurônios/metabolismo , Transdução de Sinais
6.
eNeuro ; 11(1)2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38164611

RESUMO

The anterior dorsolateral striatum (DLS) is heavily innervated by convergent excitatory projections from the primary motor (M1) and sensory cortex (S1) and considered an important site of sensorimotor integration. M1 and S1 corticostriatal synapses have functional differences in their connection strength with striatal spiny projection neurons (SPNs) and fast-spiking interneurons (FSIs) in the DLS and, as a result, exert distinct influences on sensory-guided behaviors. In the present study, we tested whether M1 and S1 inputs exhibit differences in the subcellular anatomical distribution of striatal neurons. We injected adeno-associated viral vectors encoding spaghetti monster fluorescent proteins (sm.FPs) into M1 and S1 in male and female mice and used confocal microscopy to generate 3D reconstructions of corticostriatal inputs to single identified SPNs and FSIs obtained through ex vivo patch clamp electrophysiology. We found that M1 and S1 dually innervate SPNs and FSIs; however, there is a consistent bias towards the M1 input in SPNs that is not found in FSIs. In addition, M1 and S1 inputs were distributed similarly across the proximal, medial, and distal regions of SPN and FSI dendrites. Notably, closely localized M1 and S1 clusters of inputs were more prevalent in SPNs than FSIs, suggesting that cortical inputs are integrated through cell-type specific mechanisms. Our results suggest that the stronger functional connectivity from M1 to SPNs compared to S1, as previously observed, is due to a higher quantity of synaptic inputs. Our results have implications for how sensorimotor integration is performed in the striatum through cell-specific differences in corticostriatal connections.


Assuntos
Neurônios , Vibrissas , Camundongos , Masculino , Feminino , Animais , Neurônios/fisiologia , Interneurônios/fisiologia , Corpo Estriado/metabolismo , Neostriado
7.
J Neurosci ; 44(4)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38050130

RESUMO

Body movements influence brain-wide neuronal activities. In the sensory cortex, thalamocortical bottom-up inputs and motor-sensory top-down inputs are thought to affect the dynamics of membrane potentials (Vm ) of neurons and change their processing of sensory information during movements. However, direct perturbation of the axons projecting to the sensory cortex from other remote areas during movements has remained unassessed, and therefore the interareal circuits generating motor-related signals in sensory cortices remain unclear. Using a Gi/o -coupled opsin, eOPN3, we here inhibited interareal signals incoming to the whisker primary somatosensory barrel cortex (wS1) of awake male mice and tested their effects on whisking-related changes in neuronal activities in wS1. Spontaneous whisking in air induced the changes in spike rates of a subset of wS1 neurons, which were accompanied by depolarization and substantial reduction of slow-wave oscillatory fluctuations of Vm Despite an extensive innervation, inhibition of inputs from the whisker primary motor cortex (wM1) to wS1 did not alter the spike rates and Vm dynamics of wS1 neurons during whisking. In contrast, inhibition of axons from the whisker-related thalamus (wTLM) and the whisker secondary somatosensory cortex (wS2) to wS1 largely attenuated the whisking-related supra- and sub-threshold Vm dynamics of wS1 neurons. Notably, silencing inputs from wTLM markedly decreased the modulation depth of whisking phase-tuned neurons in wS1, while inhibiting wS2 inputs did not impact the whisking variable tuning of wS1 neurons. Thus, sensorimotor integration in wS1 during spontaneous whisking is predominantly facilitated by direct synaptic inputs from wTLM and wS2 rather than from wM1.


Assuntos
Neurônios , Córtex Somatossensorial , Camundongos , Masculino , Animais , Neurônios/fisiologia , Córtex Somatossensorial/fisiologia , Axônios , Potenciais da Membrana , Movimento , Vibrissas/fisiologia
8.
J Physiol ; 602(1): 153-181, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37987552

RESUMO

The whisker system is widely used as a model system for understanding sensorimotor integration. Purkinje cells in the crus regions of the cerebellum have been reported to linearly encode whisker midpoint, but it is unknown whether the paramedian and simplex lobules as well as their target neurons in the cerebellar nuclei also encode whisker kinematics and if so which ones. Elucidating how these kinematics are represented throughout the cerebellar hemisphere is essential for understanding how the cerebellum coordinates multiple sensorimotor modalities. Exploring the cerebellar hemisphere of mice using optogenetic stimulation, we found that whisker movements can be elicited by stimulation of Purkinje cells in not only crus1 and crus2, but also in the paramedian lobule and lobule simplex; activation of cells in the medial paramedian lobule had on average the shortest latency, whereas that of cells in lobule simplex elicited similar kinematics as those in crus1 and crus2. During spontaneous whisking behaviour, simple spike activity correlated in general better with velocity than position of the whiskers, but it varied between protraction and retraction as well as per lobule. The cerebellar nuclei neurons targeted by the Purkinje cells showed similar activity patterns characterized by a wide variety of kinematic signals, yet with a dominance for velocity. Taken together, our data indicate that whisker movements are much more prominently and diversely represented in the cerebellar cortex and nuclei than assumed, highlighting the rich repertoire of cerebellar control in the kinematics of movements that can be engaged during coordination. KEY POINTS: Excitation of Purkinje cells throughout the cerebellar hemispheres induces whisker movement, with the shortest latency and longest duration within the paramedian lobe. Purkinje cells have differential encoding for the fast and slow components of whisking. Purkinje cells encode not only the position but also the velocity of whiskers. Purkinje cells with high sensitivity for whisker velocity are preferentially located in the medial part of lobule simplex, crus1 and lateral paramedian. In the downstream cerebellar nuclei, neurons with high sensitivity for whisker velocity are located at the intersection between the medial and interposed nucleus.


Assuntos
Cerebelo , Vibrissas , Camundongos , Animais , Vibrissas/fisiologia , Fenômenos Biomecânicos , Cerebelo/fisiologia , Células de Purkinje/fisiologia , Córtex Cerebelar
9.
Anat Rec (Hoboken) ; 307(2): 442-456, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37644754

RESUMO

Rats' whisking motion and objects' palpation produce tactile signals sensed by mechanoreceptors at the vibrissal follicles. Rats adjust their whisking patterns to target information type, flow, and resolution, adapting to their behavioral needs and the changing environment. This coordination requires control over the activity of the mystacial pad's intrinsic and extrinsic muscles. Studies have relied on muscle recording and stimulation techniques to describe the roles of individual muscles. However, these methods lack the resolution to isolate the mystacial pad's small and compactly arranged muscles. Thus, we propose functional anatomy as a complementary approach for studying the individual and coordinated effects of the mystacial pad muscles on vibrissae movements. Our functional analysis addresses the kinematic measurements of whisking motion patterns recorded in freely exploring rats. Combined with anatomical descriptions of muscles and fascia elements of the mystacial pad in situ, we found: (1) the contributions of individual mystacial pad muscles to the different whisking motion patterns; (2) active touch by microvibrissae, and its underlying mechanism; and (3) dynamic position changes of the vibrissae pivot point, as determined by the movements of the corium and subcapsular fibrous mat. Finally, we hypothesize that each of the rat mystacial pad muscles is specialized for a particular function in a way that matches the architecture of the fascial structures. Consistent with biotensegrity principles, the muscles and fascia form a network of structural support and continuous tension that determine the arrangement and motion of the embedded individual follicles.


Assuntos
Movimento , Músculos , Ratos , Animais , Movimento/fisiologia , Tato/fisiologia , Movimento (Física) , Vibrissas/fisiologia
10.
J Cereb Blood Flow Metab ; 44(2): 155-168, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37728791

RESUMO

Hypoglycemia is a serious complication of insulin treatment of diabetes that can lead to coma and death. Neurovascular coupling, which mediates increased local blood flow in response to neuronal activity, increases glucose availability to active neurons. This mechanism could be essential for neuronal health during hypoglycemia, when total glucose supplies are low. Previous studies suggest, however, that neurovascular coupling (a transient blood flow increase in response to an increase in neuronal activity) may be reduced during hypoglycemia. Such a reduction in blood flow increase would exacerbate the effects of hypoglycemia, depriving active neurons of glucose. We have reexamined the effects of hypoglycemia on neurovascular coupling by simultaneously monitoring neuronal and vascular responses to whisker stimulation in the awake mouse somatosensory cortex. We find that neurovascular coupling at both penetrating arterioles and at 2nd order capillaries did not change significantly during insulin-induced hypoglycemia compared to euglycemia. In addition, we show that the basal diameter of both arterioles and capillaries increases during hypoglycemia (10.3 and 9.7% increases, respectively). Our results demonstrate that both neurovascular coupling and basal increases in vessel diameter are active mechanisms which help to maintain an adequate supply of glucose to the brain during hypoglycemia.


Assuntos
Hipoglicemia , Insulinas , Acoplamento Neurovascular , Camundongos , Animais , Acoplamento Neurovascular/fisiologia , Arteríolas/metabolismo , Capilares/metabolismo , Circulação Cerebrovascular/fisiologia , Vibrissas/fisiologia , Hipoglicemia/induzido quimicamente , Hipoglicemia/metabolismo , Glucose/metabolismo , Insulinas/metabolismo , Insulinas/farmacologia
11.
Macromol Rapid Commun ; 45(2): e2300462, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37800886

RESUMO

Avoiding collisions is a key necessity for any autonomous mobile robot, and obstacle mapping enables them to maneuver in an uncharted area. In this era of the Internet of Things, with the emerging need for a multitude of sensors, adopting self-powered technologies is more practically viable than batteries for powering the same. Herein, with the fabrication of a triboelectric artificial whisker (TAW), a self-powered obstacle detection is demonstrated via tactile perception. The mechanical contact with the obstacle gives rise to an electrical signal from the TAW owing to the embedded triboelectric sensor. In addition, the triboelectric nanogenerator (TENG) based on electrospun polyacrylonitrile (PAN) nanofibers and polydimethylsiloxane film, which facilitates this self-powered artificial sensation, generates an output voltage of 720 V and current density of 5 mA m-2 with 1.7 W m-2 of maximum power delivery from a force of 10 N. The electro-spinning aided enhancement in contact area of the PAN is responsible for the remarkable improvement in the performance of the TENG, 3.4 times enhancement in power density, when compared to the nonsurface-modified ones. In addition, the TENG is able to charge commercial capacitors up to appreciable values and demonstrates powering different electronic gadgets such as calculators and thermometers.


Assuntos
Nanofibras , Animais , Vibrissas , Resinas Acrílicas , Fontes de Energia Elétrica
12.
Cell Rep ; 43(1): 113618, 2024 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-38150365

RESUMO

Goal-directed behaviors involve coordinated activity in many cortical areas, but whether the encoding of task variables is distributed across areas or is more specifically represented in distinct areas remains unclear. Here, we compared representations of sensory, motor, and decision information in the whisker primary somatosensory cortex, medial prefrontal cortex, and tongue-jaw primary motor cortex in mice trained to lick in response to a whisker stimulus with mice that were not taught this association. Irrespective of learning, properties of the sensory stimulus were best encoded in the sensory cortex, whereas fine movement kinematics were best represented in the motor cortex. However, movement initiation and the decision to lick in response to the whisker stimulus were represented in all three areas, with decision neurons in the medial prefrontal cortex being more selective, showing minimal sensory responses in miss trials and motor responses during spontaneous licks. Our results reconcile previous studies indicating highly specific vs. highly distributed sensorimotor processing.


Assuntos
Neocórtex , Córtex Somatossensorial , Camundongos , Animais , Córtex Somatossensorial/fisiologia , Objetivos , Lobo Parietal , Neurônios , Vibrissas/fisiologia
13.
eNeuro ; 10(12)2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38053472

RESUMO

We present a cost-effective, compact foot-print, and open-source Raspberry Pi-based widefield imaging system. The compact nature allows the system to be used for close-proximity dual-brain cortical mesoscale functional-imaging to simultaneously observe activity in two head-fixed animals in a staged social touch-like interaction. We provide all schematics, code, and protocols for a rail system where head-fixed mice are brought together to a distance where the macrovibrissae of each mouse make contact. Cortical neuronal functional signals (GCaMP6s; genetically encoded Ca2+ sensor) were recorded from both mice simultaneously before, during, and after the social contact period. When the mice were together, we observed bouts of mutual whisking and cross-mouse correlated cortical activity across the cortex. Correlations were not observed in trial-shuffled mouse pairs, suggesting that correlated activity was specific to individual interactions. Whisking-related cortical signals were observed during the period where mice were together (closest contact). The effects of social stimulus presentation extend outside of regions associated with mutual touch and have global synchronizing effects on cortical activity.


Assuntos
Cálcio , Percepção do Tato , Camundongos , Animais , Gravidez , Feminino , Encéfalo/fisiologia , Cabeça , Tato , Vibrissas/fisiologia , Córtex Somatossensorial/fisiologia
14.
Cell Rep ; 42(12): 113532, 2023 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-38064338

RESUMO

Sensory cortical areas are organized into topographic maps representing the sensory epithelium. Interareal projections typically connect topographically matched subregions across areas. Because matched subregions process the same stimulus, their interaction is central to many computations. Here, we ask how topographically matched subregions of primary and secondary vibrissal somatosensory cortices (vS1 and vS2) interact during active touch. Volumetric calcium imaging in mice palpating an object with two whiskers revealed a sparse population of highly responsive, broadly tuned touch neurons especially pronounced in layer 2 of both areas. These rare neurons exhibited elevated synchrony and carried most touch-evoked activity in both directions. Lesioning the subregion of either area responding to the spared whiskers degraded touch responses in the unlesioned area, with whisker-specific vS1 lesions degrading whisker-specific vS2 touch responses. Thus, a sparse population of broadly tuned touch neurons dominates vS1-vS2 communication in both directions, and topographically matched vS1 and vS2 subregions recurrently amplify whisker touch activity.


Assuntos
Percepção do Tato , Tato , Camundongos , Animais , Tato/fisiologia , Percepção do Tato/fisiologia , Neurônios/fisiologia , Córtex Somatossensorial/fisiologia , Vibrissas/fisiologia , Estimulação Física
15.
Artigo em Inglês | MEDLINE | ID: mdl-38083760

RESUMO

This paper presents a high-speed rat whisker tracking and symmetry analysis system based on FPGA. The system utilizes high-speed image sensors recording rat face videos at 120 and 1000 fps. The Xilinx Ultra96 single computer board is chosen as the platform to implement the system's processing system (PS) and the programmable logic (PL) part. The PL part is responsible for high-speed image processing and whisker tracking, while the PS part analyzes the symmetry of rat face using the tracking results from the PL part. With a processing speed FoM of 118.5 fps/GHz on the Xilinx Ultra96 single computer board and 275.47 fps/GHz on a laptop with Intel Core i5-11500T@1.5GHz, the presented system achieves excellent performance. The proposed whisker detection method has a precision of 98.2% when a threshold with a 4-degree error is selected, with an average error angle of 0.98 degrees across more than 10,000 video frames. Moreover, the proposed system is capable of local video processing within millisecond delays. These results demonstrate the feasibility of developing a high-speed, accurate, and efficient whisker tracking and symmetry analysis system for rat behavior research.


Assuntos
Processamento de Imagem Assistida por Computador , Vibrissas , Ratos , Animais , Processamento de Imagem Assistida por Computador/métodos
16.
Curr Biol ; 33(22): R1195-R1197, 2023 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-37989098

RESUMO

New work reveals whisker landmark coding in the retrosplenial cortex of mice, broadening our understanding of multisensory spatial cognition, contextual processing, and spatial predictive coding.


Assuntos
Navegação Espacial , Percepção do Tato , Animais , Camundongos , Cognição , Giro do Cíngulo , Tato , Vibrissas
17.
J Exp Biol ; 226(22)2023 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-38035544

RESUMO

For the two dolphin species Sotalia guianensis (Guiana dolphin) and Tursiops truncatus (bottlenose dolphin), previous research has shown that the vibrissal crypts located on the rostrum represent highly innervated, ampullary electroreceptors and that both species are correspondingly sensitive to weak electric fields. In the present study, for a comparative assessment of the sensitivity of the bottlenose dolphin's electroreceptive system, we determined detection thresholds for DC and AC electric fields with two bottlenose dolphins. In a psychophysical experiment, the animals were trained to respond to electric field stimuli using the go/no-go paradigm. We show that the two bottlenose dolphins are able to detect DC electric fields as low as 2.4 and 5.5 µV cm-1, respectively, a detection threshold in the same order of magnitude as those in the platypus and the Guiana dolphin. Detection thresholds for AC fields (1, 5 and 25 Hz) were generally higher than those for DC fields, and the sensitivity for AC fields decreased with increasing frequency. Although the electroreceptive sensitivity of dolphins is lower than that of elasmobranchs, it is suggested that it allows for both micro- and macro-scale orientation. In dolphins pursuing benthic foraging strategies, electroreception may facilitate short-range prey detection and target-oriented snapping of their prey. Furthermore, the ability to detect weak electric fields may enable dolphins to perceive the Earth's magnetic field through induction-based magnetoreception, thus allowing large-scale orientation.


Assuntos
Golfinho Nariz-de-Garrafa , Animais , Sensação , Vibrissas
18.
Bioinspir Biomim ; 19(1)2023 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-37939394

RESUMO

Pinniped vibrissae possess a unique and complex three-dimensional topography, which has beneficial fluid flow characteristics such as substantial reductions in drag, lift, and vortex induced vibration. To understand and leverage these effects, the downstream vortex dynamics must be studied. Dye visualization is a traditional qualitative method of capturing these downstream effects, specifically in comparative biological investigations where complex equipment can be prohibitive. High-fidelity numerical simulations or experimental particle image velocimetry are commonplace for quantitative high-resolution flow measurements, but are computationally expensive, require costly equipment, and can have limited measurement windows. This study establishes a method for extracting quantitative data from standard dye visualization experiments on seal whisker geometries by leveraging novel but intuitive computer vision techniques, which maintain simplicity and an advantageous large experimental viewing window while automating the extraction of vortex frequency, position, and advection. Results are compared to direct numerical simulation (DNS) data for comparable geometries. Power spectra and Strouhal numbers show consistent behavior between methods for a Reynolds number of 500, with minima at the canonical geometry wavelength of 3.43 and a peak frequency of 0.2 for a Reynolds number of 250. The vortex tracking reveals a clear increase in velocity from roll-up to 3.5 whisker diameters downstream, with a strong overlap with the DNS data but shows steady results beyond the limited DNS window. This investigation provides insight into a valuable bio-inspired engineering model while advancing an analytical methodology that can readily be applied to a broad range of comparative biological studies.


Assuntos
Caniformia , Focas Verdadeiras , Animais , Vibrissas , Vibração , Simulação por Computador
19.
Nat Commun ; 14(1): 6112, 2023 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-37777516

RESUMO

To localize objects during active sensing, animals must differentiate stimuli caused by volitional movement from real-world object motion. To determine a neural basis for this ability, we examined the mouse superior colliculus (SC), which contains multiple egocentric maps of sensorimotor space. By placing mice in a whisker-guided virtual reality, we discovered a rapidly adapting tactile response that transiently emerged during externally generated gains in whisker contact. Responses to self-generated touch that matched self-generated history were significantly attenuated, revealing that transient response magnitude is controlled by sensorimotor predictions. The magnitude of the transient response gradually decreased with repetitions in external motion, revealing a slow habituation based on external history. The direction of external motion was accurately encoded in the firing rates of transiently responsive neurons. These data reveal that whisker-specific adaptation and sensorimotor predictions in SC neurons enhance the localization of unexpected, externally generated changes in tactile space.


Assuntos
Percepção do Tato , Tato , Camundongos , Animais , Tato/fisiologia , Percepção do Tato/fisiologia , Neurônios/fisiologia , Movimento (Física) , Movimento , Vibrissas/fisiologia
20.
Sci Rep ; 13(1): 14205, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37679413

RESUMO

CRISPR/Cas9-based genome editing represents an unprecedented potential for plant breeding. Unlike animal cells, plant cells contain a rigid cell wall, genome editing tool delivery into plant cells is thus challenging. In particular, the delivery of the Cas9-gRNA ribonucleoprotein (RNP) into plant cells is desired since the transgene insertion into the genome should be avoided for industrial applications in plants. In this study, we present a novel RNP delivery approach in rice. We applied the sonication-assisted whisker method, conventionally developed for DNA delivery in plants, for RNP delivery in rice. Combined with marker gene delivery, we successfully isolated OsLCYß genome-edited lines generated by RNPs. The calli and regenerated shoot of the OsLCYß mutant showed abnormal carotenoid accumulation. In addition, we also detected, although at a low frequency, genome editing events in rice calli cells by RNP delivery using the sonication-assisted whisker method without any additional. Therefore, the sonication-assisted whisker method could be an attractive way to create RNP-based genome-edited lines in plants.


Assuntos
Calosidades , Oryza , Animais , Oryza/genética , Sistemas CRISPR-Cas , Edição de Genes , Sonicação , Vibrissas , Melhoramento Vegetal , Ribonucleoproteínas/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...