-
The Journal of Neuroscience : the... Mar 2023A learned sensory-motor behavior engages multiple brain regions, including the neocortex and the basal ganglia. How a target stimulus is detected by these regions and...
A learned sensory-motor behavior engages multiple brain regions, including the neocortex and the basal ganglia. How a target stimulus is detected by these regions and converted to a motor response remains poorly understood. Here, we performed electrophysiological recordings and pharmacological inactivations of whisker motor cortex and dorsolateral striatum to determine the representations within, and functions of, each region during performance in a selective whisker detection task in male and female mice. From the recording experiments, we observed robust, lateralized sensory responses in both structures. We also observed bilateral choice probability and preresponse activity in both structures, with these features emerging earlier in whisker motor cortex than dorsolateral striatum. These findings establish both whisker motor cortex and dorsolateral striatum as potential contributors to the sensory-to-motor (sensorimotor) transformation. We performed pharmacological inactivation studies to determine the necessity of these brain regions for this task. We found that suppressing the dorsolateral striatum severely disrupts responding to task-relevant stimuli, without disrupting the ability to respond, whereas suppressing whisker motor cortex resulted in more subtle changes in sensory detection and response criterion. Together these data support the dorsolateral striatum as an essential node in the sensorimotor transformation of this whisker detection task. Selecting an item in a grocery store, hailing a cab - these daily practices require us to transform sensory stimuli into motor responses. Many decades of previous research have studied goal-directed sensory-to-motor transformations within various brain structures, including the neocortex and the basal ganglia. Yet, our understanding of how these regions coordinate to perform sensory-to-motor transformations is limited because these brain structures are often studied by different researchers and through different behavioral tasks. Here, we record and perturb specific regions of the neocortex and the basal ganglia and compare their contributions during performance of a goal-directed somatosensory detection task. We find notable differences in the activities and functions of these regions, which suggests specific contributions to the sensory-to-motor transformation process.
Topics: Mice; Male; Female; Animals; Vibrissae; Learning; Corpus Striatum; Neostriatum; Neocortex; Somatosensory Cortex
PubMed: 36810226
DOI: 10.1523/JNEUROSCI.1506-22.2023 -
Nutrients Jan 2023Hordenine is effective in treating hyperpigmentation, fighting diabetes and resisting fibrosis and acute inflammation. However, the role of Hordenine on hair growth has...
Hordenine is effective in treating hyperpigmentation, fighting diabetes and resisting fibrosis and acute inflammation. However, the role of Hordenine on hair growth has not been elucidated. Here, we found that Hordenine treatments significantly enhance proliferation of primary mouse dermal-papilla cells (DPCs) and increase the activity of DPCs in a dose-dependent manner. Additionally, Hordenine markedly promoted the elongation of the hair shaft in the model of in vitro-cultured mouse vibrissa follicle and accelerated hair regrowth in a mouse model of depilation-induced hair regeneration. Real-time PCR, Western Blot and immunofluorescent assays showed that nuclear β-catenin and its downstream gene expression such as Lef1, Axin2, Cyclin D1 and ALP were greatly upregulated in DPCs and mouse hair follicles after Hordenine treatments. Moreover, the increased DPCs' proliferation and hair shaft elongation of cultured mouse vibrissa follicles induced by Hordenine treatments were rescued by a Wnt/β-catenin signaling inhibitor, FH535. These data indicate that Hordenine can effectively enhance DPCs' activity and accelerate hair regrowth through activating the Wnt/β-catenin signaling pathway. Therefore, these findings suggest Hordenine/its derivatives may be potentially used for preventing and treating alopecia in the future.
Topics: Mice; Animals; Wnt Signaling Pathway; Hair Follicle; beta Catenin; Cells, Cultured; Hair; Cell Proliferation
PubMed: 36771401
DOI: 10.3390/nu15030694 -
Acta Neurobiologiae Experimentalis 2022Intrinsic signal optical imaging (ISOI) has been used previously for the detection of changes in sensory processing in the somatosensory cortex in response to...
Intrinsic signal optical imaging (ISOI) has been used previously for the detection of changes in sensory processing in the somatosensory cortex in response to environment alteration or after deprivation of sensory information. To date, there have been no reports of ISOI being used in learning‑induced changes in the somatosensory cortex. In the present study, ISOI was performed twice in the same mouse: before and after conditional fear learning. The conditioning paradigm consisted of pairing sensory stimulation of vibrissae with electric tail shock. In order to map the cortical representation of the vibrissa B1 with ISOI, we deflected the vibrissa with an intensive stimulation (frequency of 10 Hz for 6 s). After conditioning, we found that the cortical representation of vibrissa B1 had expanded by an average of 44%, compared with pre‑learning, by using images obtained with ISOI. Previously, we demonstrated an enlargement of the cortical representation of the vibrissae stimulated by the same behavioral training paradigm but using [14C]2‑deoxyglucose. This current investigation provides the first ISOI‑based evidence of learning‑induced changes in plasticity in the barrel cortex. The results indicate that irrespective of physiological mechanisms used for visualization of the vibrissae representation or subject's testing state (aware or anesthetized animal), the conditioning induced changes in each case in the cortical processing of intensive stimuli. This suggests specific functional reorganization of the neuronal circuits. Moreover, ISOI as a noninvasive method of mapping cortical activation in the same animal before and after behavioral training could serve as a very useful tool for precise manipulation within the cortex and for assessing the resulting effects on experience‑dependent cortical plasticity.
Topics: Mice; Animals; Somatosensory Cortex; Neurons; Conditioning, Classical; Vibrissae; Optical Imaging; Neuronal Plasticity
PubMed: 36748972
DOI: 10.55782/ane-2022-047 -
Proceedings. Biological Sciences Feb 2023Whiskers are important tactile structures widely used across mammals for a variety of sensory functions, but it is not known how bats-representing about a fifth of all...
Whiskers are important tactile structures widely used across mammals for a variety of sensory functions, but it is not known how bats-representing about a fifth of all extant mammal species-use them. Nectar-eating bats typically have long vibrissae (long, stiff hairs) arranged in a forward-facing brush-like formation that is not present in most non-nectarivorous bats. They also commonly use a unique flight strategy to access their food-hovering flight. Here we investigated whether these species use their vibrissae to optimize their feeding by assisting fine flight control. We used behavioural experiments to test if bats' flight trajectory into the flower changed after vibrissa removal, and phylogenetic comparative methods to test whether vibrissa length is related to nectarivory. We found that bat flight trajectory was altered after vibrissae removal and that nectarivorous bats possess longer vibrissae than non-nectivorous species, providing evidence of an additional source of information in bats' diverse sensory toolkit.
Topics: Animals; Chiroptera; Vibrissae; Phylogeny; Flowers; Food
PubMed: 36722088
DOI: 10.1098/rspb.2022.2085 -
Biomedicine & Pharmacotherapy =... Mar 2023Human embryonic stem cell (hES)-derived mesenchymal stem cells (-MSCs) are an unlimited source of MSCs. The hair growth-promoting effects of diverse MSCs have been...
Human embryonic stem cell (hES)-derived mesenchymal stem cells (-MSCs) are an unlimited source of MSCs. The hair growth-promoting effects of diverse MSCs have been reported, but not that of hES-MSCs. In the present study, we investigated the hair growth-promoting effects of hES-MSCs and their underlying mechanisms. hES-MSCs or conditioned medium of hES-MSCs exhibited hair-growth effects, which increased the length of mouse vibrissae and human hair follicles. hES-MSCs accelerated the telogen-to-anagen transition in C3H mice and were more effective than adipose-derived stem cells. We further examined whether hypoxia could enhance the hair-growth promoting effects of hES-MSCs. The injection of hES-MSCs or conditioned medium (Hyp-CM) cultured under hypoxia (2% O) enhanced the telogen-to-anagen transition in C3H mice. Additionally, Hyp-CM increased the length of mouse vibrissae, human hair follicles, and the proliferation of human dermal papilla and outer root sheath cells. Moreover, fibroblast growth factor 7, interleukin 12B, and teratocarcinoma-derived growth factor 1 were upregulated under hypoxia, and the co-treatment with these three proteins increased the hair length and induced telogen-to-anagen transition. Hypoxia increased reactive oxygen species (ROS) production, and ROS scavenging attenuated the secretion of growth factors. NADPH oxidase 4 was primarily expressed in hES-MSCs and generated ROS under hypoxia. Collectively, our results suggest that hES-MSCs exhibit hair-growth effects, which is enhanced by hypoxia.
Topics: Humans; Animals; Mice; NADPH Oxidase 4; Reactive Oxygen Species; Culture Media, Conditioned; Mice, Inbred C3H; Cell Proliferation; Hair Follicle; Mesenchymal Stem Cells; Embryonic Stem Cells; Intercellular Signaling Peptides and Proteins; Hypoxia; Cells, Cultured
PubMed: 36706635
DOI: 10.1016/j.biopha.2023.114303 -
Experimental Neurobiology Dec 2022There is a scarcity of experimental studies on peripheral nerve regeneration using placental extract (PE). This study aimed to investigate the effects of topical PE...
There is a scarcity of experimental studies on peripheral nerve regeneration using placental extract (PE). This study aimed to investigate the effects of topical PE application on recovery after crush injury to the rat facial nerve using functional, electrophysiological, and morphological evaluations. The viability of the RSC96 Schwann cells treated with PE (0.5~4 mg/ml) increased significantly. Immunoblot test revealed that PE application enhanced the migration of RSC96 cells. Quantitative polymerase chain reaction demonstrated that PE increased the expression of neurotropic genes. The recovery from vibrissa fibrillation in the PE-treated group was superior to that in the control group. The threshold of action potential was also significantly lower in the PE group. Histopathological examination showed that crushed facial nerves treated with PE exhibited larger axons. The surrounding myelin sheaths were more distinct and thicker in the PE-treated group. Hence, PE may be considered a topical therapeutic agent for treating traumatic facial nerve paralysis.
PubMed: 36631850
DOI: 10.5607/en22006 -
PloS One 2023Facial vibrissae (whiskers) are thin, tapered, flexible, hair-like structures that are an important source of tactile sensory information for many species of mammals. In...
Facial vibrissae (whiskers) are thin, tapered, flexible, hair-like structures that are an important source of tactile sensory information for many species of mammals. In contrast to insect antennae, whiskers have no sensors along their lengths. Instead, when a whisker touches an object, the resulting deformation is transmitted to mechanoreceptors in a follicle at the whisker base. Previous work has shown that the mechanical signals transmitted along the whisker will depend strongly on the whisker's geometric parameters, specifically on its taper (how diameter varies with arc length) and on the way in which the whisker curves, often called "intrinsic curvature." Although previous studies have largely agreed on how to define taper, multiple methods have been used to quantify intrinsic curvature. The present work compares and contrasts different mathematical approaches towards quantifying this important parameter. We begin by reviewing and clarifying the definition of "intrinsic curvature," and then show results of fitting whisker shapes with several different functions, including polynomial, fractional exponent, elliptical, and Cesàro. Comparisons are performed across ten species of whiskered animals, ranging from rodents to pinnipeds. We conclude with a discussion of the advantages and disadvantages of using the various models for different modeling situations. The fractional exponent model offers an approach towards developing a species-specific parameter to characterize whisker shapes within a species. Constructing models of how the whisker curves is important for the creation of mechanical models of tactile sensory acquisition behaviors, for studies of comparative evolution, morphology, and anatomy, and for designing artificial systems that can begin to emulate the whisker-based tactile sensing of animals.
Topics: Animals; Vibrissae; Mammals; Touch; Touch Perception; Caniformia
PubMed: 36607960
DOI: 10.1371/journal.pone.0269210 -
Journal of Neurophysiology Feb 2023Neural plasticity of the brain or its ability to reorganize following injury has likely coincided with the successful clinical correction of severe deformity by facial...
Neural plasticity of the brain or its ability to reorganize following injury has likely coincided with the successful clinical correction of severe deformity by facial transplantation since 2005. In this study, we present the cortical reintegration outcomes following syngeneic hemifacial vascularized composite allograft (VCA) in a small animal model. Specifically, changes in the topographic organization and unit response properties of the rodent whisker-barrel somatosensory system were assessed following hemifacial VCA. Clear differences emerged in the barrel-cortex system when comparing naïve and hemiface transplanted animals. Neurons in the somatosensory cortex of transplanted rats had decreased sensitivity albeit increased directional sensitivity compared with naïve rats and evoked responses in transplanted animals were more temporally dispersed. In addition, receptive fields were often topographically mismatched with the indication that the mismatched topography reorganized within adjacent barrel (same row-arc bias following hemifacial transplant). These results suggest subcortical changes in the thalamus and/or brainstem play a role in hemifacial transplantation cortical plasticity and demonstrate the discrete and robust data that can be derived from this clinically relevant small animal VCA model for use in optimizing postsurgical outcomes. Robust rodent hemifacial transplant model was used to record functional changes in somatosensory cortex after transplantation. Neurons in the somatosensory cortex of face transplant recipients had decreased sensitivity to stimulation of whiskers with increased directional sensitivity vs. naive rats. Transplant recipient cortical unit response was more dispersed in temporary vs. naive rats. Despite histological similarities to naive cortices, transplant recipient cortices had a mix of topographically appropriate and inappropriate whiskered at barrel cortex relationships.
Topics: Rats; Animals; Facial Transplantation; Neurons; Thalamus; Somatosensory Cortex; Vibrissae; Physical Stimulation
PubMed: 36542405
DOI: 10.1152/jn.00349.2022 -
International Journal of Molecular... Dec 2022Recovery of mimic function after facial nerve transection is poor. The successful regrowth of regenerating motor nerve fibers to reinnervate their targets is compromised... (Review)
Review
Recovery of mimic function after facial nerve transection is poor. The successful regrowth of regenerating motor nerve fibers to reinnervate their targets is compromised by (i) poor axonal navigation and excessive collateral branching, (ii) abnormal exchange of nerve impulses between adjacent regrowing axons, namely axonal crosstalk, and (iii) insufficient synaptic input to the axotomized facial motoneurons. As a result, axotomized motoneurons become hyperexcitable but unable to discharge. We review our findings, which have addressed the poor return of mimic function after facial nerve injuries, by testing the hypothesized detrimental component, and we propose that intensifying the trigeminal sensory input to axotomized and electrophysiologically silent facial motoneurons improves the specificity of the reinnervation of appropriate targets. We compared behavioral, functional, and morphological parameters after single reconstructive surgery of the facial nerve (or its buccal branch) with those obtained after identical facial nerve surgery, but combined with direct or indirect stimulation of the ipsilateral infraorbital nerve. We found that both methods of trigeminal sensory stimulation, i.e., stimulation of the vibrissal hairs and manual stimulation of the whisker pad, were beneficial for the outcome through improvement of the quality of target reinnervation and recovery of vibrissal motor performance.
Topics: Rats; Animals; Facial Nerve Injuries; Nerve Regeneration; Rats, Wistar; Facial Nerve; Vibrissae; Recovery of Function
PubMed: 36499425
DOI: 10.3390/ijms232315101 -
Scientific Reports Dec 2022Stimulation of hair growth in hair loss has been a difficult goal to achieve. Hair follicle-associated pluripotent (HAP) stem cells express nestin and have been shown to...
Stimulation of hair growth in hair loss has been a difficult goal to achieve. Hair follicle-associated pluripotent (HAP) stem cells express nestin and have been shown to differentiate to multiple cell types including keratinocytes, neurons, beating cardiac muscles and numerous other cell types. HAP stem cells originate in the bulge area of the hair follicle and have been shown to migrate within and outside the hair follicle. In the present study, the upper part of vibrissa follicles from nestin-driven green-fluorescent protein (GFP) transgenic mice, containing GFP-expressing HAP stem cells, were transplanted in the dorsal area of athymic nude mice. Fluorescence microscopy and immunostaining showed the transplanted HAP stem cells jumped and targeted the bulge and hair bulb and other areas of the resident nude mouse pelage follicles where they differentiated to keratinocytes. These results indicate that transplanted nestin-GFP expressing HAP stem cells jumped from the upper part of the whisker follicles and targeted nude-mouse hair follicles, which are genetically deficient to grow normal hair shafts, and differentiated to keratinocytes to produce normal mature hair shafts. The resident nude-mouse pelage follicles targeted by jumping whisker HAP stem cells produced long hair shafts from numerous hair follicles for least 2 hair cycles during 36 days, demonstrations that HAP stem cells can stimulate hair growth. The present results for hair loss therapy are discussed.
Topics: Animals; Mice; Hair Follicle; Mice, Nude; Alopecia; Stem Cells
PubMed: 36476963
DOI: 10.1038/s41598-022-25383-z