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Journal of Neuroscience Methods Jan 2023Studying natural, complex behaviours over a range of different species provides insights into the evolution of the brain and behaviour. Whisker movements reveal complex...
BACKGROUND
Studying natural, complex behaviours over a range of different species provides insights into the evolution of the brain and behaviour. Whisker movements reveal complex behaviours; however, there does not yet exist a protocol that is able to capture whisker movements and behaviours in a range of different species.
NEW METHOD
We develop a new protocol and make recommendations for measuring comparative whisker movements and behaviours. Using two set-ups - an enclosure camera set-up and a high-speed video set-up - we capture and measure the whisker movements of sixteen different captive mammal species from four different animal collections.
RESULTS
We demonstrate the ability to describe whisker movements and behaviours across a wide range of mammalian species. We describe whisker movements in European hedgehog, Cape porcupine, domestic rabbit, domestic ferret, weasel, European otter and red fox for the first time. We observe whisker movements in all the species we tested, although movement, positions and behaviours vary in a species-specific way.
COMPARISON WITH EXISTING METHOD(S)
The high-speed video set-up is based on the protocols of previous studies. The addition of an enclosure video set-up is entirely new, and allows us to include more species, especially large and shy species that cannot be moved into a high-speed filming arena.
CONCLUSIONS
We make recommendations for comparative whisker behaviour studies, particularly incorporating individual and species-specific considerations. We believe that flexible, comparative behavioural protocols have wide-ranging applications, specifically to better understand links between the brain and complex behaviours.
Topics: Animals; Rabbits; Vibrissae; Ferrets; Movement; Mammals; Touch
PubMed: 36435328
DOI: 10.1016/j.jneumeth.2022.109752 -
Advanced Science (Weinheim,... Jan 2023Seals can detect prey up to 180 m away using only their flow-sensing whiskers. The unique undulating morphology of Phocid seal whiskers reduces vortex-induced vibrations...
Seals can detect prey up to 180 m away using only their flow-sensing whiskers. The unique undulating morphology of Phocid seal whiskers reduces vortex-induced vibrations (VIVs), rendering seals highly sensitive to biologically relevant flow stimuli. In this work, digital models of harbor and grey seal whiskers are extracted using 3D scanning and a mathematical framework that accurately recreates their undulating geometry is proposed. Through fluid-structure interaction studies and experimental investigations involving a whisker array mounted on 3D-printed microelectromechanical systems sensors, the vibration characteristics of the whisker array and the interaction between neighboring whiskers in steady flows and fish-wake-like vortices are explained for the first time. Results reveal that the downstream vortices intensity and resulting VIVs are consistently lower for grey than harbor seal whiskers and a smooth cylinder, suggesting that the grey seal whisker geometry can be an ideal template for the biomimetic design of VIV-resistant underwater structures. In addition, neighboring whiskers in an array influence one another by resulting in greater flow vorticity fluctuation and distribution area, thus causing increased vibrations than an isolated whisker, which indicates the possibility of a signal-strengthening effect in whisker arrays.
Topics: Animals; Vibrissae; Hydrodynamics; Phoca; Vibration; Biomimetics
PubMed: 36403235
DOI: 10.1002/advs.202203062 -
Scientific Reports Nov 2022Pseudoxanthoma elasticum (PXE) is a multisystem, genetic, ectopic mineralization disorder with no effective treatment. Inhibition of tissue-nonspecific alkaline...
Anticalcification effects of DS-1211 in pseudoxanthoma elasticum mouse models and the role of tissue-nonspecific alkaline phosphatase in ABCC6-deficient ectopic calcification.
Pseudoxanthoma elasticum (PXE) is a multisystem, genetic, ectopic mineralization disorder with no effective treatment. Inhibition of tissue-nonspecific alkaline phosphatase (TNAP) may prevent ectopic soft tissue calcification by increasing endogenous pyrophosphate (PPi). This study evaluated the anticalcification effects of DS-1211, an orally administered, potent, and highly selective small molecule TNAP inhibitor, in mouse models of PXE. Calcium content in vibrissae was measured in KK/HlJ and ABCC6 mice after DS-1211 administration for 13-14 weeks. Pharmacokinetic and pharmacodynamic effects of DS-1211 were evaluated, including plasma alkaline phosphatase (ALP) activity and biomarker changes in PPi and pyridoxal-phosphate (PLP). Anticalcification effects of DS-1211 through TNAP inhibition were further evaluated in ABCC6 mice with genetically reduced TNAP activity, ABCC6/TNAP and ABCC6/TNAP. In KK/HlJ and ABCC6 mouse models, DS-1211 inhibited plasma ALP activity in a dose-dependent manner and prevented progression of ectopic calcification compared with vehicle-treated mice. Plasma PPi and PLP increased dose-dependently with DS-1211 in ABCC6 mice. Mice with ABCC6/TNAP phenotype had significantly less calcification and higher plasma PPi and PLP than ABCC6/TNAP mice. TNAP plays an active role in pathomechanistic pathways of dysregulated calcification, demonstrated by reduced ectopic calcification in mice with lower TNAP activity. DS-1211 may be a potential therapeutic drug for PXE.
Topics: Mice; Animals; Pseudoxanthoma Elasticum; Alkaline Phosphatase; Disease Models, Animal; Phenotype; Calcinosis; Multidrug Resistance-Associated Proteins
PubMed: 36400944
DOI: 10.1038/s41598-022-23892-5 -
ENeuro 2022Angular tuning is preferential sensory response to a directional stimulus and is observed in the whisker tactile system. In whisker hair follicles, there are at least...
Angular tuning is preferential sensory response to a directional stimulus and is observed in the whisker tactile system. In whisker hair follicles, there are at least three types of low threshold mechanoreceptors (LTMRs): rapidly adapting (RA), slowly adapting type 1 (SA1), and slowly adapting type 2 (SA2). These LTMRs display angular tuning but their properties remain incompletely studied. Here, we used isolated rat whisker hair follicles and pressure-clamped single-fiber recordings to study angular tuning of these LTMRs. Angular tuning was determined with impulses elicited by ramp-and-hold deflection of whisker hair in 24 directions each at 15° for a total of 360°. We show that RA display impulses during ramp-up, both ramp-up and ramp-down, or ramp-down dynamic phases. Both SA1 and SA2 respond to angular stimuli with slowly adapting impulses in most angles. However, SA1 and SA2 show rapidly adapting responses in other angles. All the three types of LTMRs display strong angular tuning, and there is no significant difference in angular tuning index among them. Population wise, the majority of SA1 are tuned in the caudal direction, a large part of SA2 is tuned in the rostral direction, and RAs are tuned in multiple directions. In the angles showing strong tuning, the three LTMRs respond to increased stimulation amplitudes with increased impulse numbers in a hyperbola relationship, and the responsiveness based on impulse numbers is SA2 > SA1 > RA. Our findings provide new information on angular tuning properties of LTMRs in whisker hair follicles and help to understand directional encoding.
Topics: Rats; Animals; Vibrissae; Hair Follicle; Mechanoreceptors; Hair; Touch
PubMed: 36376066
DOI: 10.1523/ENEURO.0175-22.2022 -
Scientific Reports Nov 2022Inhibitory interneurons play central roles in the modulation of spontaneous network activity and in processing of neuronal information. In sensory neocortical areas,...
Inhibitory interneurons play central roles in the modulation of spontaneous network activity and in processing of neuronal information. In sensory neocortical areas, parvalbumin-positive (PV+) GABAergic interneurons control the representation and processing of peripheral sensory inputs. We studied the functional role of PV+ interneurons in the barrel cortex of anesthetized adult PVCre mice by combining extracellular multi-electrode recordings with optogenetic silencing of a small fraction of PV+ interneurons. In all cortical layers, optogenetic inhibition caused an increase in spontaneous network activity from theta to gamma frequencies. The spatio-temporal representation of sensory inputs was studied by stimulating one or two whiskers at different intervals and analyzing the resulting local field potential (LFP) and single unit (SU) response. Silencing PV+ interneurons caused an increase in LFP response to sensory stimulation and a decrease in temporal discrimination of consecutive whisker deflections. The combined effect of whisker deflection and optogenetic inhibition was highly similar to the linear sum of the individual effects of these two manipulations. SU recordings revealed that optogenetic silencing reduced stimulus detectability by increasing stimulus-evoked firing rate by a constant offset, suggesting that PV+ interneurons improve signal-to-noise ratio by reducing ongoing spiking activity, thereby sharpening the spatio-temporal representation of sensory stimuli.
Topics: Animals; Parvalbumins; Optogenetics; Somatosensory Cortex; Interneurons; Vibrissae
PubMed: 36371511
DOI: 10.1038/s41598-022-24156-y -
Nature Communications Nov 2022Rodent sensory cortex contains salt-and-pepper maps of sensory features, whose structure is not fully known. Here we investigated the structure of the salt-and-pepper...
Rodent sensory cortex contains salt-and-pepper maps of sensory features, whose structure is not fully known. Here we investigated the structure of the salt-and-pepper whisker somatotopic map among L2/3 pyramidal neurons in somatosensory cortex, in awake mice performing one-vs-all whisker discrimination. Neurons tuned for columnar (CW) and non-columnar (non-CW) whiskers were spatially intermixed, with co-tuned neurons forming local (20 µm) clusters. Whisker tuning was markedly unstable in expert mice, with 35-46% of pyramidal cells significantly shifting tuning over 5-18 days. Tuning instability was highly concentrated in non-CW tuned neurons, and thus was structured in the map. Instability of non-CW neurons was unchanged during chronic whisker paralysis and when mice discriminated individual whiskers, suggesting it is an inherent feature. Thus, L2/3 combines two distinct components: a stable columnar framework of CW-tuned cells that may promote spatial perceptual stability, plus an intermixed, non-columnar surround with highly unstable tuning.
Topics: Mice; Animals; Vibrissae; Somatosensory Cortex; Neurons; Pyramidal Cells; Wakefulness; Rodentia
PubMed: 36329010
DOI: 10.1038/s41467-022-34261-1 -
ENeuro 2022Primary sensory cortices display functional topography, suggesting that even small cortical volumes may underpin perception of specific stimuli. Traditional...
Primary sensory cortices display functional topography, suggesting that even small cortical volumes may underpin perception of specific stimuli. Traditional loss-of-function approaches have a relatively large radius of effect (>1 mm), and few studies track recovery following loss-of-function perturbations. Consequently, the behavioral necessity of smaller cortical volumes remains unclear. In the mouse primary vibrissal somatosensory cortex (vS1), "barrels" with a radius of ∼150 μm receive input predominantly from a single whisker, partitioning vS1 into a topographic map of well defined columns. Here, we train animals implanted with a cranial window over vS1 to perform single-whisker perceptual tasks. We then use high-power laser exposure centered on the barrel representing the spared whisker to produce lesions with a typical volume of one to two barrels. These columnar-scale lesions impair performance in an object location discrimination task for multiple days without disrupting vibrissal kinematics. Animals with degraded location discrimination performance can immediately perform a whisker touch detection task with high accuracy. Animals trained on both simple and complex whisker touch detection tasks showed no permanent behavioral deficits following columnar-scale lesions. Thus, columnar-scale lesions permanently degrade performance in object location discrimination tasks.
Topics: Mice; Animals; Somatosensory Cortex; Vibrissae; Touch Perception; Touch; Cerebral Cortex
PubMed: 36316120
DOI: 10.1523/ENEURO.0393-22.2022 -
Biomedicines Oct 2022mutant mice are one of the rare mutant strains that do not develop whisker hair follicles while still displaying a pelage. Here, we show that is expressed at the...
mutant mice are one of the rare mutant strains that do not develop whisker hair follicles while still displaying a pelage. Here, we show that is expressed at the earliest stage of whisker development in clusters of mesenchymal cells before placode formation. Its conditional knockout in the murine soma leads to the loss of expression of , , , , , and , though leaving the β-catenin-driven first dermal signal intact. Furthermore, we show that expressing cells not only act as a signaling center but also as a multipotent progenitor population contributing to the several lineages of the adult whisker. We confirm by genetic ablation experiments that the absence of macro vibrissae reverberates on the organization of nerve wiring in the mystacial pads and leads to the reorganization of the barrel cortex. We demonstrate that acts upstream of and identify a primate-specific deletion of a enhancer named Leaf. This loss may have been significant in the evolutionary process, leading to the progressive defunctionalization and disappearance of vibrissae in primates.
PubMed: 36289911
DOI: 10.3390/biomedicines10102647 -
Scientific Reports Oct 2022The activity of inhibitory interneurons has a profound role in shaping cortical plasticity. Somatostatin-expressing interneurons (SOM-INs) are involved in several...
The activity of inhibitory interneurons has a profound role in shaping cortical plasticity. Somatostatin-expressing interneurons (SOM-INs) are involved in several aspects of experience-dependent cortical rewiring. We addressed the question of the barrel cortex SOM-IN engagement in plasticity formation induced by sensory deprivation in adult mice (2-3 months old). We used a spared vibrissa paradigm, resulting in a massive sensory map reorganization. Using chemogenetic manipulation, the activity of barrel cortex SOM-INs was blocked or activated by continuous clozapine N-oxide (CNO) administration during one-week-long deprivation. To visualize the deprivation-induced plasticity, [C]-2-deoxyglucose mapping of cortical functional representation of the spared whisker was performed at the end of the deprivation. The plasticity was manifested as an extension of cortical activation in response to spared vibrissae stimulation. We found that SOM-IN inhibition in the cortical column of the spared whisker did not influence the areal extent of the cortex activated by the spared whisker. However, blocking the activity of SOM-INs in the deprived column, adjacent to the spared one, decreased the plasticity of the spared whisker representation. SOM-IN activation did not affect plasticity. These data show that SOM-IN activity is part of cortical circuitry that affects interbarrel interactions underlying deprivation-induced plasticity in adult mice.
Topics: Mice; Animals; Vibrissae; Somatosensory Cortex; Neuronal Plasticity; Interneurons; Somatostatin; Deoxyglucose
PubMed: 36289269
DOI: 10.1038/s41598-022-22801-0 -
Cell Reports Oct 2022Behavioral flexibility is the ability to adjust behavioral strategies in response to changing environmental contingencies. A major hypothesis in the field posits that...
Behavioral flexibility is the ability to adjust behavioral strategies in response to changing environmental contingencies. A major hypothesis in the field posits that the activity of neurons in the locus coeruleus (LC) plays an important role in mediating behavioral flexibility. To test this hypothesis, we developed a tactile-based rule-shift detection task in which mice responded to left and right whisker deflections in a context-dependent manner and exhibited varying degrees of switching behavior. Recording spiking activity from optogenetically tagged neurons in the LC at millisecond precision during task performance revealed a prominent graded correlation between baseline LC activity and behavioral flexibility, where higher baseline activity following a rule change was associated with faster behavioral switching to the new rule. Increasing baseline LC activity with optogenetic activation accelerated task switching and improved task performance. Overall, our study provides important evidence to reveal the link between LC activity and behavioral flexibility.
Topics: Mice; Animals; Locus Coeruleus; Optogenetics; Neurons; Vibrissae; Behavior, Animal
PubMed: 36288712
DOI: 10.1016/j.celrep.2022.111534