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PLoS Computational Biology Sep 2021Rats and mice use their whiskers to probe the environment. By rhythmically swiping their whiskers back and forth they can detect the existence of an object, locate it,...
Rats and mice use their whiskers to probe the environment. By rhythmically swiping their whiskers back and forth they can detect the existence of an object, locate it, and identify its texture. Localization can be accomplished by inferring the whisker's position. Rhythmic neurons that track the phase of the whisking cycle encode information about the azimuthal location of the whisker. These neurons are characterized by preferred phases of firing that are narrowly distributed. Consequently, pooling the rhythmic signal from several upstream neurons is expected to result in a much narrower distribution of preferred phases in the downstream population, which however has not been observed empirically. Here, we show how spike timing dependent plasticity (STDP) can provide a solution to this conundrum. We investigated the effect of STDP on the utility of a neural population to transmit rhythmic information downstream using the framework of a modeling study. We found that under a wide range of parameters, STDP facilitated the transfer of rhythmic information despite the fact that all the synaptic weights remained dynamic. As a result, the preferred phase of the downstream neuron was not fixed, but rather drifted in time at a drift velocity that depended on the preferred phase, thus inducing a distribution of preferred phases. We further analyzed how the STDP rule governs the distribution of preferred phases in the downstream population. This link between the STDP rule and the distribution of preferred phases constitutes a natural test for our theory.
Topics: Action Potentials; Animals; Computational Biology; Computer Simulation; Evoked Potentials, Somatosensory; Learning; Mechanoreceptors; Mice; Models, Neurological; Motor Neurons; Neuronal Plasticity; Rats; Somatosensory Cortex; Thalamus; Vibrissae
PubMed: 34534208
DOI: 10.1371/journal.pcbi.1009353 -
Neuron May 2006The behavioral state of an animal is accompanied by ongoing brain activity that primes neuronal circuitry to sensory inputs. While it should come as no surprise that the... (Review)
Review
The behavioral state of an animal is accompanied by ongoing brain activity that primes neuronal circuitry to sensory inputs. While it should come as no surprise that the pattern of cortical activation is tied to behavioral states, only now has this dependence been imaged. In this issue of Neuron, Ferezou, Bolea, and Petersen show that the level and spatial extent of activation of vibrissa sensory cortex critically depend on behavioral context and mode of stimulation, i.e., passive versus active contact.
Topics: Anesthesia, General; Animals; Behavior, Animal; Brain Mapping; Mice; Research Design; Somatosensory Cortex; Touch; Vibrissae; Wakefulness
PubMed: 16701202
DOI: 10.1016/j.neuron.2006.05.004 -
Nature Communications Nov 2020Vasocative-intestinal-peptide (VIP) and somatostatin (SST) interneurons are involved in modulating barrel cortex activity and perception during active whisking. Here we...
Vasocative-intestinal-peptide (VIP) and somatostatin (SST) interneurons are involved in modulating barrel cortex activity and perception during active whisking. Here we identify a developmental transition point of structural and functional rearrangements onto these interneurons around the start of active sensation at P14. Using in vivo two-photon Ca imaging, we find that before P14, both interneuron types respond stronger to a multi-whisker stimulus, whereas after P14 their responses diverge, with VIP cells losing their multi-whisker preference and SST neurons enhancing theirs. Additionally, we find that Ca signaling dynamics increase in precision as the cells and network mature. Rabies virus tracings followed by tissue clearing, as well as photostimulation-coupled electrophysiology reveal that SST cells receive higher cross-barrel inputs compared to VIP neurons at both time points. In addition, whereas prior to P14 both cell types receive direct input from the sensory thalamus, after P14 VIP cells show reduced inputs and SST cells largely shift to motor-related thalamic nuclei.
Topics: Animals; Calcium; Electrophysiology; Female; Image Processing, Computer-Assisted; Interneurons; Male; Mice; Microscopy, Confocal; Models, Animal; Nervous System; Neurons; Rabbits; Somatostatin; Thalamus; Vasoactive Intestinal Peptide; Vibrissae
PubMed: 33184269
DOI: 10.1038/s41467-020-19427-z -
The Journal of Neuroscience : the... Dec 2019A central function of the brain is to plan, predict, and imagine the effect of movement in a dynamically changing environment. Here we show that in mice head-fixed in a...
A central function of the brain is to plan, predict, and imagine the effect of movement in a dynamically changing environment. Here we show that in mice head-fixed in a plus-maze, floating on air, and trained to pick lanes based on visual stimuli, the asymmetric movement, and position of whiskers on the two sides of the face signals whether the animal is moving, turning, expecting reward, or licking. We show that (1) whisking asymmetry is coordinated with behavioral state, and that behavioral state can be decoded and predicted based on asymmetry, (2) even in the absence of tactile input, whisker positioning and asymmetry nevertheless relate to behavioral state, and (3) movement of the nose correlates with asymmetry, indicating that facial expression of the mouse is itself correlated with behavioral state. These results indicate that the movement of whiskers, a behavior that is not instructed or necessary in the task, can inform an observer about what a mouse is doing in the maze. Thus, the position of these mobile tactile sensors reflects a behavioral and movement-preparation state of the mouse. Behavior is a sequence of movements, where each movement can be related to or can trigger a set of other actions. Here we show that, in mice, the movement of whiskers (tactile sensors used to extract information about texture and location of objects) is coordinated with and predicts the behavioral state of mice: that is, what mice are doing, where they are in space, and where they are in the sequence of behaviors.
Topics: Animals; Behavior, Animal; Exploratory Behavior; Facial Expression; Functional Laterality; Male; Maze Learning; Mice; Mice, Inbred C57BL; Nose; Orientation; Photic Stimulation; Psychomotor Performance; Somatosensory Cortex; Touch; Vibrissae
PubMed: 31666357
DOI: 10.1523/JNEUROSCI.1809-19.2019 -
Experimental Neurology Dec 2003
Review
Topics: Animals; Brain Mapping; Humans; Neuronal Plasticity; Somatosensory Cortex; Vibrissae
PubMed: 14769350
DOI: 10.1016/S0014-4886(03)00396-0 -
Cell Reports Apr 2022The topographic organization is a prominent feature of sensory cortices, but its functional role remains controversial. Particularly, it is not well determined how...
The topographic organization is a prominent feature of sensory cortices, but its functional role remains controversial. Particularly, it is not well determined how integration of activity within a cortical area depends on its topography during sensory-guided behavior. Here, we train mice expressing channelrhodopsin in excitatory neurons to track a photostimulation bar that rotated smoothly over the topographic whisker representation of the primary somatosensory cortex. Mice learn to discriminate angular positions of the light bar to obtain a reward. They fail not only when the spatiotemporal continuity of the photostimulation is disrupted in this area but also when cortical areas displaying map discontinuities, such as the trunk and legs, or areas without topographic map, such as the posterior parietal cortex, are photostimulated. In contrast, when cortical topographic continuity enables to predict future sensory activation, mice demonstrate anticipation of reward availability. These findings could be helpful for optimizing feedback while designing cortical neuroprostheses.
Topics: Animals; Channelrhodopsins; Learning; Mice; Neurons; Somatosensory Cortex; Vibrissae
PubMed: 35385729
DOI: 10.1016/j.celrep.2022.110617 -
The Journal of Comparative Neurology Mar 2020The barrel cortex is within the primary somatosensory cortex of the rodent, and processes signals from the vibrissae. Much focus has been devoted to the function of...
The barrel cortex is within the primary somatosensory cortex of the rodent, and processes signals from the vibrissae. Much focus has been devoted to the function of neurons, more recently, the role of glial cells in the processing of sensory input has gained increasing interest. Microglia are the principal immune cells of the nervous system that survey and regulate the cellular constituents of the dynamic nervous system. We investigated the normal and disrupted development of microglia in barrel cortex by chronically depriving sensory signals via whisker trimming for the animals' first postnatal month. Using immunohistochemistry to label microglia, we performed morphological reconstructions as well as densitometry analyses as a function of developmental age and sensory experience. Findings suggest that both developmental age and sensory experience has profound impact on microglia morphology. Following chronic sensory deprivation, microglia undergo a morphological transition from a monitoring or resting state to an altered morphological state, by exhibiting expanded cell body size and retracted processes. Sensory restoration via whisker regrowth returns these morphological alterations back to age-matched control values. Our results indicate that microglia may be recruited to participate in the modulation of neuronal structural remodeling during developmental critical periods and in response to alteration in sensory input.
Topics: Animals; Animals, Newborn; Female; Male; Mice; Microglia; Neuronal Plasticity; Sensory Deprivation; Somatosensory Cortex; Vibrissae
PubMed: 31502243
DOI: 10.1002/cne.24771 -
Nature Communications Sep 2022Sensory input arrives from thalamus in cortical layer (L) 4, which outputs predominantly to superficial layers. L4 to L2 thus constitutes one of the earliest cortical...
Sensory input arrives from thalamus in cortical layer (L) 4, which outputs predominantly to superficial layers. L4 to L2 thus constitutes one of the earliest cortical feedforward networks. Despite extensive study, the transformation performed by this network remains poorly understood. We use two-photon calcium imaging to record neural activity in L2-4 of primary vibrissal somatosensory cortex (vS1) as mice perform an object localization task with two whiskers. Touch responses sparsen and become more reliable from L4 to L2, with nearly half of the superficial touch response confined to ~1 % of excitatory neurons. These highly responsive neurons have broad receptive fields and can more accurately decode stimulus features. They participate disproportionately in ensembles, small subnetworks with elevated pairwise correlations. Thus, from L4 to L2, cortex transitions from distributed probabilistic coding to sparse and robust ensemble-based coding, resulting in more efficient and accurate representations.
Topics: Animals; Calcium; Mice; Neurons; Somatosensory Cortex; Touch Perception; Vibrissae
PubMed: 36123376
DOI: 10.1038/s41467-022-33249-1 -
Journal of Neurophysiology Jan 2017Sensory stimulation drives complex interactions across neural circuits as information is encoded and then transmitted from one brain region to the next. In the highly...
UNLABELLED
Sensory stimulation drives complex interactions across neural circuits as information is encoded and then transmitted from one brain region to the next. In the highly interconnected thalamocortical circuit, these complex interactions elicit repeatable neural dynamics in response to temporal patterns of stimuli that provide insight into the circuit properties that generated them. Here, using a combination of in vivo voltage-sensitive dye (VSD) imaging of cortex, single-unit recording in thalamus, and optogenetics to manipulate thalamic state in the rodent vibrissa pathway, we probed the thalamocortical circuit with simple temporal patterns of stimuli delivered either to the whiskers on the face (sensory stimulation) or to the thalamus directly via electrical or optogenetic inputs (artificial stimulation). VSD imaging of cortex in response to whisker stimulation revealed classical suppressive dynamics, while artificial stimulation of thalamus produced an additional facilitation dynamic in cortex not observed with sensory stimulation. Thalamic neurons showed enhanced bursting activity in response to artificial stimulation, suggesting that bursting dynamics may underlie the facilitation mechanism we observed in cortex. To test this experimentally, we directly depolarized the thalamus, using optogenetic modulation of the firing activity to shift from a burst to a tonic mode. In the optogenetically depolarized thalamic state, the cortical facilitation dynamic was completely abolished. Together, the results obtained here from simple probes suggest that thalamic state, and ultimately thalamic bursting, may play a key role in shaping more complex stimulus-evoked dynamics in the thalamocortical pathway.
NEW & NOTEWORTHY
For the first time, we have been able to utilize optogenetic modulation of thalamic firing modes combined with optical imaging of cortex in the rat vibrissa system to directly test the role of thalamic state in shaping cortical response properties.
Topics: Action Potentials; Afferent Pathways; Analysis of Variance; Animals; Channelrhodopsins; Electric Stimulation; Female; Luminescent Proteins; Neurons; Nonlinear Dynamics; Optogenetics; Rats; Rats, Sprague-Dawley; Somatosensory Cortex; Thalamus; Transduction, Genetic; Vibrissae; Voltage-Sensitive Dye Imaging; Red Fluorescent Protein
PubMed: 27760816
DOI: 10.1152/jn.00415.2016 -
Developmental Biology Apr 2012Mammary glands and hair follicles develop as ectodermal organs sharing common features during embryonic morphogenesis. The molecular signals controlling the initiation...
Mammary glands and hair follicles develop as ectodermal organs sharing common features during embryonic morphogenesis. The molecular signals controlling the initiation and patterning of skin appendages involve the bone morphogenetic proteins and Wnt family members, which are commonly thought to serve as inhibitory and activating cues, respectively. Here, we have examined the role of the Bmp and Wnt pathway modulator Sostdc1 in mammary gland, and hair and vibrissa follicle development using Sostdc1-null mice. Contrary to previous speculations, loss of Sostdc1 did not affect pelage hair cycling. Instead, we found that Sostdc1 limits the number of developing vibrissae and other muzzle hair follicles, and the size of primary hair placodes. Sostdc1 controls also the size and shape of mammary buds. Furthermore, Sostdc1 is essential for suppression of hair follicle fate in the normally hairless nipple epidermis, but its loss also promotes the appearance of supernumerary nipple-like protrusions. Our data suggest that functions of Sostdc1 can be largely attributed to its ability to attenuate Wnt/β-catenin signaling.
Topics: Adaptor Proteins, Signal Transducing; Animals; Bone Morphogenetic Proteins; Female; Gene Expression Regulation, Developmental; Hair; Mammary Glands, Animal; Mice; Skin; Vibrissae; Wnt Signaling Pathway
PubMed: 22509524
DOI: 10.1016/j.ydbio.2012.01.026