Whisker Movements Research Articles

Effects of arousal and movement on secondary somatosensory and visual thalamus.

Neocortical sensory areas have associated primary and secondary thalamic nuclei. While primary nuclei transmit sensory information to cortex, secondary nuclei remain poorly understood. We recorded juxtasomally from secondary somatosensory (POm) and visual (LP) nuclei of awake mice while tracking whisking and pupil size. POm activity correlated with whisking, but not precise whisker kinematics. This coarse movement modulation persisted after facial paralysis and thus was not due to sensory reafference. This phenomenon also continued during optogenetic silencing of somatosensory and motor cortex and after lesion of superior colliculus, ruling out a motor efference copy mechanism. Whisking and pupil dilation were strongly correlated, possibly reflecting arousal. Indeed LP, which is not part of the whisker system, tracked whisking equally well, further indicating that POm activity does not encode whisker movement per se. The semblance of movement-related activity is likely instead a global effect of arousal on both nuclei. We conclude that secondary thalamus monitors behavioral state, rather than movement, and may exist to alter cortical activity accordingly.

Organic electrolytic photocapacitors for stimulation of the mouse somatosensory cortex

Objective. For decades electrical stimulation has been used in neuroscience to investigate brain networks and been deployed clinically as a mode of therapy. Classically, all methods of electrical stimulation require implanted electrodes to be connected in some manner to an apparatus which provides power for the stimulation itself. Approach. We show the use of novel organic electronic devices, specifically organic electrolytic photocapacitors (OEPCs), which can be activated when illuminated with deep-red wavelengths of light and correspondingly do not require connections with external wires or power supplies when implanted at various depths in vivo. Main results. We stimulated cortical brain tissue of mice with devices implanted subcutaneously, as well as beneath both the skin and skull to demonstrate a wireless stimulation of the whisker motor cortex. Devices induced both a behavior response (whisker movement) and a sensory response in the corresponding sensory cortex. Additionally, we showed that coating OEPCs with a thin layer of a conducting polymer formulation (PEDOT:PSS) significantly increases their charge storage capacity, and can be used to further optimize the applied photoelectrical stimulation. Significance. Overall, this new technology can provide an on-demand electrical stimulation by simply using an OEPC and a deep-red wavelength illumination. Wires and interconnects to provide power to implanted neurostimulation electrodes are often problematic in freely-moving animal research and with implanted electrodes for long-term therapy in patients. Our wireless brain stimulation opens new perspectives for wireless electrical stimulation for applications in fundamental neurostimulation and in chronic therapy.

California sea lions employ task-specific strategies for active touch sensing.

ABSTRACTActive sensing is the process of moving sensors to extract task-specific information. Whisker touch is often referred to as an active sensory system as whiskers are moved with purposeful control. Even though whisker movements are found in many species, it is unknown whether any animal can make task-specific movements with their whiskers. California sea lions (Zalophus californianus) make large, purposeful whisker movements and are capable of performing many whisker-related discrimination tasks. Therefore, California sea lions are an ideal species to explore the active nature of whisker touch sensing. Here, we show that California sea lions can make task-specific whisker movements. California sea lions move their whiskers with large amplitudes around object edges to judge size, make smaller, lateral stroking movements to judge texture and make very small whisker movements during a visual task. These findings, combined with the ease of training mammals and measuring whisker movements, makes whiskers an ideal system for studying mammalian perception, cognition and motor control.

Whisker trimming during infanthood modifies the development of spike-wave discharges and behavioral sequences in IntelliCage impulsivity paradigm in adult WAG/Rij rats

Whisker system in rats undergoes rapid development during the first postnatal weeks. Neonatal whisker trimming increases excitability in the somatosensory cortex and affects exploratory behavior at adult ages. WAG/Rij rats are genetically predisposed to develop absence seizures in adulthood, and whisker trimming during three postnatal weeks aggravates epileptic activity in these rats. It is assumed that behavioral performance in adult WAG/Rij rats is influenced (1) by absence epilepsy and (2) by whisker trimming during the short period around the onset of active whisker movements, PN9–16. We examined the effect of whisker trimming in WAG/Rij rats during PN9–16 on spike-wave discharges (SWD, EEG hallmark of absence epilepsy). We found that 77% of WAG/Rij rats showed pronounced SWD (epileptic phenotype), and the rest did not (non-epileptic phenotype). At the age of 5 m, epileptic trimmed rats showed more SWD than epileptic control rats. Age-related increase of SWD was found only in the control group, suggesting that whisker trimming during PN9–16 led to an earlier maturation of SWD. Goal-directed behavior was examined in all rats at the age of 4–4.5 m using IntelliCage impulsivity paradigm. In order to optimize the analysis of behavioral data, we combined several Python packages into a single processing pipeline. Early life whisker trimming altered behavioral sequences and strategy of exploration in adulthood, suggesting reduced whisker sensitivity in the trimmed rats. Epileptic WAG/Rij rats at 4–4.5 months showed only a slight learning impairment during later stages of IntelliCage impulsivity paradigm, which may be associated with the early stage of development of SWD.

Bidirectional Control of Orienting Behavior by the Substantia Nigra Pars Reticulata: Distinct Significance of Head and Whisker Movements.

Detection of an unexpected, novel, or salient stimulus typically leads to an orienting response by which animals move the head, in concert with the sensors (e.g., eyes, pinna, whiskers), to evaluate the stimulus. The basal ganglia are known to control orienting movements through tonically active GABAergic neurons in the substantia nigra pars reticulata (SNr) that project to the superior colliculus. Using optogenetics, we explored the ability of GABAergic SNr neurons on one side of the brain to generate orienting movements. In a strain of mice that express channelrhodopsin (ChR2) in both SNr GABAergic neurons and afferent fibers, we found that continuous blue light produced a robust sustained excitation of SNr neurons which generated ipsiversive orienting. Conversely, in the same animal, trains of blue light excited afferent fibers more effectively than continuous blue light, producing a robust sustained inhibition of SNr neurons which generated contraversive orienting. When ChR2 expression was restricted to either GABAergic SNr neurons or GABAergic afferent fibers from the striatum, blue light patterns in SNr produced only ipsiversive or contraversive orienting movements, respectively. Interestingly, whisker positioning and the reaction to an air-puff on the whiskers were incongruent between SNr-evoked ipsiversive and contraversive head movements, indicating that orienting driven by exciting or inhibiting SNr neurons have different behavioral significance. In conclusion, unilateral SNr neuron excitation and inhibition produce orienting movements in opposite directions and, apparently, with distinct behavioral significance.

Synapses from the Motor Cortex and a High-Order Thalamic Nucleus are Spatially Clustered in Proximity to Each Other in the Distal Tuft Dendrites of Mouse Somatosensory Cortex.

The posterior medial nucleus of the thalamus (POm) and vibrissal primary motor cortex (vM1) convey essential information to the barrel cortex (S1BF) regarding whisker position and movement. Therefore, understanding the relative spatial relationship of these two inputs is a critical prerequisite for acquiring insights into how S1BF synthesizes information to interpret the location of an object. Using array tomography, we identified the locations of synapses from vM1 and POm on distal tuft dendrites of L5 pyramidal neurons where the two inputs are combined. Synapses from vM1 and POm did not show a significant branchlet preference and impinged on the same set of dendritic branchlets. Within dendritic branches, on the other hand, the two inputs formed robust spatial clusters of their own type. Furthermore, we also observed POm clusters in proximity to vM1 clusters. This work constitutes the first detailed description of the relative distribution of synapses from POm and vM1, which is crucial to elucidate the synaptic integration of whisker-based sensory information.

Sensorimotor strategies and neuronal representations for shape discrimination

Humans and other animals can identify objects by active touch, requiring the coordination of exploratory motion and tactile sensation. Both the motor strategies and neural representations employed could depend on the subject's goals. We developed a shape discrimination task that challenged head-fixed mice to discriminate concave from convex shapes. Behavioral decoding revealed that mice did this by comparing contacts across whiskers. In contrast, a separate group of mice performing a shape detection task simply summed up contacts over whiskers. We recorded populations of neurons in the barrel cortex, which processes whisker input, and found that individual neurons across the cortical layers encoded touch, whisker motion, and task-related signals. Sensory representations were task-specific: during shape discrimination, but not detection, neurons responded most to behaviorally relevant whiskers, overriding somatotopy. Thus, sensory cortex employs task-specific representations compatible with behaviorally relevant computations.

Arousal Promoting Effects of Basal Forebrain are Mediated through Prefrontal Cortex in Rat

Background We recently showed that cholinergic stimulation of prefrontal cortex (PFC), via local carbachol delivery, increased local acetylcholine (ACh) levels and restored wakefulness in sevoflurane-anesthetized rats.[1] PFC receives cholinergic projections from basal forebrain (BF), and activation of cholinergic BF neurons has been shown to promote behavioral arousal.[2] Increase in prefrontal ACh during carbachol-induced wake state reflects BF activation, but it is not known if BF acts via PFC to promote behavioral arousal. The objective of the current study is to test the hypothesis that PFC gates the arousal promoting effects of BF. Methods Under isoflurane anesthesia, Sprague Dawley rats (n=3) were implanted with bipolar wire electrodes (500um diameter) bilaterally into BF (Bregma: posterior 0.48mm, mediolateral 2.0mm, ventral 8.2mm), screw electrodes across the cortex to record electroencephalogram (EEG), and a bilateral guide cannula aimed at PFC (Bregma: anterior 3.0mm, mediolateral 0.5mm, ventral 4.0mm). Another group of Sprague Dawley rats (n=2) was implanted with the electrical stimulation electrodes into piriform cortex (Bregma: posterior 0.48mm, mediolateral 5.0mm, ventral 9.0mm), as a control anatomical site. All coordinates are as per the stereotaxic atlas by Paxinos and Watson.[3] After 7-10 days of post-surgical recovery, we conducted bilateral constant current electrical stimulation of BF (200Hz, 30s ON and 30s OFF - three cycles at 60uA and three cycles at 100uA) in sevoflurane-anesthetized rats (1.9-2.4%) with or without concurrent inactivation of PFC via local bilateral infusion of tetrodotoxin (156µM, 500nL). The same paradigm was used for electrical stimulation of piriform cortex. Results Electrical stimulation of BF in sevoflurane-anesthetized rats induced signs of behavioral arousal (whisker, orofacial and limb movements, and attempts at/regaining of the righting reflex), activated the EEG, and increased the heart (~13%) and respiration (~67%) rate. By contrast, electrical stimulation of BF in the presence of tetrodotoxin in PFC failed to induce behavioral arousal and EEG activation. Electrical stimulation of the control anatomical site (piriform cortex) in sevoflurane-anesthetized rat did not induce behavioral arousal. Conclusions These results suggest that the arousal promoting effects of BF are gated through PFC, potentially through a cholinergic circuit.

Increased Expression of Toll-like Receptor 2 mRNA after Facial Nerve Injury in Rat

Abstract Objectives: The aim of this study was to determine whether TLRs mRNA is expressed in the distal facial nerve after facial nerve injury. Methods: The adult male Sprague-Dawley with a body weight of 200–250g underwent injury of unilateral facial nerve. Crush or cutting injury was given at the midpoint between the facial nerve trunk and the facial nerve branch. The whisker movement of vibrissae muscle was examined 4 and 14 days after facial nerve injury. The normal facial nerve on the left side and the damaged facial nerve on the right side were taken under the inhalation anesthesia and real-time polymerase chain reaction was performed. Results: In the whisker movement of vibrissae muscle, the crush group and the cutting group showed worse scores on the 14th day than the 4th scores in each group (p<0.05). On the 4th day of injury, the expression of TLR 7 mRNA was highest in the crush group, and on the 14th day of injury, the expression of TLR 7 mRNA was highest in the cutting group. On the 14th day of injury, the expression of TLR 2 mRNA was significantly higher in the cutting group than in the control group (p<0.05), on the 4th day of injury, the expression of TLR 9, 13 mRNA was significantly lower in the crush and cutting groups than in the control group (p<0.05). Conclusions: The expression of TLR 2 mRNA in the distal facial nerve after facial nerve injury in the cutting group was significantly higher than that in the control group, but the expressions of TLR 9 and 13 mRNA in the crush and cutting groups were significantly low. Therefore, TLR mRNA may be involved in facial nerve damage and regeneration.

Vagus nerve stimulation induces widespread cortical and behavioral activation

Vagus nerve stimulation (VNS) is used for management of a variety of neurological conditions, although the therapeutic mechanisms are not fully understood. Accumulating evidence suggests that VNS may modulate cortical state and plasticity through activation of broadly projecting neuromodulatory systems. Using a mouse model, we compared arousal-linked behaviors with dorsal cortical activity obtained with widefield and two-photon GCaMP6s calcium imaging and electrophysiological recordings. We observed robust and reliable cortical and behavioral dose-dependent activation in waking mice to VNS, including pupil dilation and, frequently, whisker movements and locomotion. Widefield calcium imaging and multiunit recording during VNS revealed that this observed increase in arousal state is coupled with a rapid and widespread increase in excitatory activity, including, but not limited to, activation of somatosensory, visual, motor, retrosplenial, and auditory cortical regions. Two-photon GCaMP6s calcium imaging of cholinergic and noradrenergic cortical axons revealed that VNS strongly activates these neuromodulatory systems. Importantly, VNS-evoked activation of neuromodulatory axons and excitatory neurons in the cortex persisted in mice under light anesthesia, in the absence of overt movement. Arousal state changes were abolished by vagus nerve transection, confirming that observed VNS effects were specific to nerve stimulation and triggered widespread activity above that which can be explained by motor activity. Taken together, our results support a model of VNS in which activation of subcortical structures leads to widespread activation of cortex and an increase in arousal state, at least partially due to the activation of cholinergic and noradrenergic modulatory pathways.

An implantable optogenetic stimulator wirelessly powered by flexible photovoltaics with near-infrared (NIR) light

Optogenetics is a cutting-edge tool in neuroscience that employs light-sensitive proteins and controlled illumination for neuromodulation. Its main advantage is the ability to demonstrate causal relationships by manipulating the activity of specific neuronal populations and observing behavioral phenotypes. However, the tethering system used to deliver light to optogenetic tools can constrain both natural animal behaviors and experimental design. Here, we present an optically powered and controlled wireless optogenetic system using near-infrared (NIR) light for high transmittance through live tissues. In vivo optogenetic stimulations using this system induced whisker movement in channelrhodopsin-expressing mice, confirming the photovoltaics-generated electrical power was sufficient, and the remote controlling system operated successfully. The proposed optogenetic system provides improved optogenetic applications in freely moving animals.

Vagus Nerve Stimulation Induces Widespread Cortical and Behavioral Activation

Vagus nerve stimulation (VNS) is used for management of a variety of neurological conditions, although the therapeutic mechanisms are not fully understood. Accumulating evidence suggests that VNS may modulate cortical state and plasticity through activation of broadly projecting neuromodulatory systems. Using a mouse model, we compared arousal-linked behaviors with dorsal cortical activity obtained with widefield and 2-photon GCaMP6s calcium imaging and electrophysiological recordings. We observed robust and reliable cortical and behavioral dose-dependent activation in waking mice to VNS, including pupil dilation and frequently, whisker movements and locomotion. Widefield calcium imaging and multiunit recording during VNS revealed that this observed increase in arousal state is coupled with a rapid and widespread increase in excitatory activity, including, but not limited to, activation of visual, motor, retrosplenial, auditory, and barrel cortical regions. Two-photon GCaMP6s calcium imaging of cholinergic and noradrenergic cortical axons revealed that VNS strongly activates these neuromodulatory systems. Importantly, VNS-evoked activation of neuromodulatory axons and excitatory neurons in the cortex persisted in mice under light anesthesia, in the absence of overt movement, and arousal state changes were abolished by vagus nerve transection, confirming that observed VNS effects were specific to nerve stimulation and triggered widespread activity above that which can be explained by motor activity. Taken together, our results support a model of VNS in which activation of subcortical structures leads to widespread activation of cortex and an increase in arousal state, at least partially due to the activation of cholinergic and noradrenergic modulatory pathways.

Dissociating the effects of distraction and proactive interference on object memory through tests of novelty preference.

Encoding information into memory is sensitive to distraction while retrieving that memory may be compromised by proactive interference from pre-existing memories. These two debilitating effects are common in neuropsychiatric conditions, but modelling them preclinically to date is slow as it requires prolonged operant training. A step change would be the validation of functionally equivalent but fast, simple, high-throughput tasks based on spontaneous behaviour. Here, we show that spontaneous object preference testing meets these requirements in the subchronic phencyclidine rat model for cognitive impairments associated with schizophrenia. Subchronic phencyclidine rats show clear memory sensitivity to distraction in the standard novel object recognition task. However, due to this, standard novel object recognition task cannot assess proactive interference. Therefore, we compared subchronic phencyclidine performance in standard novel object recognition task to that using the continuous novel object recognition task, which offers minimal distraction, allowing disease-relevant memory deficits to be assessed directly. We first determined that subchronic phencyclidine treatment did not affect whisker movements during object exploration. Subchronic phencyclidine rats exhibited the expected distraction standard novel object recognition task effect but had intact performance on the first continuous novel object recognition task trial, effectively dissociating distraction using two novel object recognition task variants. In remaining continuous novel object recognition task trials, the cumulative discrimination index for subchronic phencyclidine rats was above chance throughout, but, importantly, their detection of object novelty was increasingly impaired relative to controls. We attribute this effect to the accumulation of proactive interference. This is the first demonstration that increased sensitivity to distraction and proactive interference, both key cognitive impairments in schizophrenia, can be dissociated in the subchronic phencyclidine rat using two variants of the same fast, simple, spontaneous object memory paradigm.

Effects of titanium prepared platelet rich fibrin on facial nerve regeneration: an experimental study

IntroductionFacial nerve damage is a condition that causes functional, psychological, and cosmetic problems; and treatment methods need to be improved. ObjectiveWe investigated the efficacy of titanium-prepared platelet-rich fibrin as a healing enhancer at the region of transection of the facial nerve. MethodsTwenty-seven New Zealand male rabbits were used in this study, divided into three experimental groups. Group 1, the sham group (n=7); Group 2, the suture group (n=10); and Group 3, the suture+T-PRF group (n=10). In Group 1, the facial nerve trunk was dissected, and no additional surgical intervention was performed. For Group 2, a transection was made to the facial nerve trunk and the nerve endings were sutured together. In Group 3, nerve endings were sutured after transection, and a titanium-prepared platelet-rich fibrin membrane was wrapped in a tube around the damaged area. All animals were followed up weekly for the presence of corneal reflex, whisker movement and low ears. Bilateral facial electromyography was performed both preoperatively and postoperatively at the 1st, 3rd, 5th, 7th, 10th weeks. Tissue samples obtained at the 10th week were histopathologically examined, and intra-group and inter-group comparisons were performed. ResultsSubjects in Group showed improvement in whisker movement and ear drop one week earlier than Group 2. In Group 3, the nerve stimulation threshold required to trigger the compound muscle action potential had returned to values similar to the preoperative control values (11.31±2.16V) by 5 weeks postoperatively (12.51±3.97V), (p=0.249). ConclusionTitanium-prepared platelet-rich fibrin administration contributed to partial nerve healing both on a functional and an electrophysiological level.

WhiskEras: A New Algorithm for Accurate Whisker Tracking.

Rodents engage in active touch using their facial whiskers: they explore their environment by making rapid back-and-forth movements. The fast nature of whisker movements, during which whiskers often cross each other, makes it notoriously difficult to track individual whiskers of the intact whisker field. We present here a novel algorithm, WhiskEras, for tracking of whisker movements in high-speed videos of untrimmed mice, without requiring labeled data. WhiskEras consists of a pipeline of image-processing steps: first, the points that form the whisker centerlines are detected with sub-pixel accuracy. Then, these points are clustered in order to distinguish individual whiskers. Subsequently, the whiskers are parameterized so that a single whisker can be described by four parameters. The last step consists of tracking individual whiskers over time. We describe that WhiskEras performs better than other whisker-tracking algorithms on several metrics. On our four video segments, WhiskEras detected more whiskers per frame than the Biotact Whisker Tracking Tool. The signal-to-noise ratio of the output of WhiskEras was higher than that of Janelia Whisk. As a result, the correlation between reflexive whisker movements and cerebellar Purkinje cell activity appeared to be stronger than previously found using other tracking algorithms. We conclude that WhiskEras facilitates the study of sensorimotor integration by markedly improving the accuracy of whisker tracking in untrimmed mice.

Independent representations of self-motion and object location in barrel cortex output.

During active tactile exploration, the dynamic patterns of touch are transduced to electrical signals and transformed by the brain into a mental representation of the object under investigation. This transformation from sensation to perception is thought to be a major function of the mammalian cortex. In primary somatosensory cortex (S1) of mice, layer 5 (L5) pyramidal neurons are major outputs to downstream areas that influence perception, decision-making, and motor control. We investigated self-motion and touch representations in L5 of S1 with juxtacellular loose-seal patch recordings of optogenetically identified excitatory neurons. We found that during rhythmic whisker movement, 54 of 115 active neurons (47%) represented self-motion. This population was significantly more modulated by whisker angle than by phase. Upon active touch, a distinct pattern of activity was evoked across L5, which represented the whisker angle at the time of touch. Object location was decodable with submillimeter precision from the touch-evoked spike counts of a randomly sampled handful of these neurons. These representations of whisker angle during self-motion and touch were independent, both in the selection of which neurons were active and in the angle-tuning preference of coactive neurons. Thus, the output of S1 transiently shifts from a representation of self-motion to an independent representation of explored object location during active touch.

Increased Purkinje Cell Complex Spike and Deep Cerebellar Nucleus Synchrony as a Potential Basis for Syndromic Essential Tremor. A Review and Synthesis of the Literature.

We review advances in understanding Purkinje cell (PC) complex spike (CS) physiology that suggest increased CS synchrony underlies syndromic essential tremor (ET). We searched PubMed for papers describing factors that affect CS synchrony or cerebellar circuits potentially related to tremor. Inferior olivary (IO) neurons are electrically coupled, with the degree of coupling controlled by excitatory and GABAergic inputs. Clusters of coupled IO neurons synchronize CSs within parasagittal bands via climbing fibers (Cfs). When motor cortex is stimulated in rats at varying frequencies, whisker movement occurs at ~10Hz, correlated with synchronous CSs, indicating that the IO/CS oscillatory rhythm gates movement frequency. Intra-IO injection of the GABAA receptor antagonist picrotoxin increases CS synchrony, increases whisker movement amplitude, and induces tremor. Harmaline and 5-HT2a receptor activation also increase IO coupling and CS synchrony and induce tremor. The hotfoot17 mouse displays features found in ET brains, including cerebellar GluRδ2 deficiency and abnormal PC Cf innervation, with IO- and PC-dependent cerebellar oscillations and tremor likely due to enhanced CS synchrony. Heightened coupling within the IO oscillator leads, through its dynamic control of CS synchrony, to increased movement amplitude and, when sufficiently intense, action tremor. Increased CS synchrony secondary to aberrant Cf innervation of multiple PCs likely also underlies hotfoot17 tremor. Deep cerebellar nucleus (DCN) hypersynchrony may occur secondary to increased CS synchrony but might also occur from PC axonal terminal sprouting during partial PC loss. Through these combined mechanisms, increased CS/DCN synchrony may plausibly underlie syndromic ET.

Touch: Fluctuating Waves of Perception

Does sensory input flow into the brain as a stream, or does it come in waves? New research shows that tactile information in the cortex rises and falls in phase with the forward and back motion of whiskers during surface exploration.

Patterns of Whisker Movement Activity in the States of Sleep and Waking in Neonatal Rats

The aims of the present work was to describe primitive whisker movements in neonatal Wistar rats (postnatal days 4–7) in the states of sleep and waking and to study correlations between whisker movements and body movements. Whisker movements were recorded by high-speed video recording and the animals’ behavioral state was determined by recording electromyographic activity of the cervical muscles and simultaneous recording of limb movements using piezo elements. During active sleep, movements consisted mostly of short-term whisker movements, and a significant proportion of these movements arose simultaneously with short-term bursts of activity in the cervical muscles and transient myoclonic twitches of the animal’s body. During periods of waking, movements were mostly complex long-lasting whisker movements, which were accompanied by long-term increases in cervical muscle tone and complex body and limb movements. Both types of whisker movement occurred mainly in the rostral and caudal directions, and the amplitude of movements during waking was only slightly greater than the amplitude of whisker movements during sleep. The data obtained here provide evidence that the temporal organization of whisker movement activity in neonatal rats is significantly different in the states of sleep and waking and that whisker movements in both behavioral states showed strong correlations with the animal’s body movements. It is suggested that generalized primitive whisker and body movements in neonatal rats are due to the activity of a single central pattern generator both in the state of active sleep and in the state of waking.

Self-Generated Whisker Movements Drive State-Dependent Sensory Input to Developing Barrel Cortex

Cortical development is an activity-dependent process [1-3]. Regarding the role of activity in the developing somatosensory cortex, one persistent debate concerns the importance of sensory feedback from self-generated movements. Specifically, recent studies claim that cortical activity is generated intrinsically, independent of movement [3, 4]. However, other studies claim that behavioral state moderates the relationship between movement and cortical activity [5-7]. Thus, perhaps inattention to behavioral state leads to failures to detect movement-driven activity [8]. Here, we resolve this issue by associating local field activity (i.e., spindle bursts) and unit activity in the barrel cortex of 5-day-old rats with whisker movements during wake and myoclonic twitches of the whiskers during active (REM) sleep. Barrel activity increased significantly within 500ms of whisker movements, especially after twitches. Also, higher-amplitude movements were more likely to trigger barrel activity; when we controlled for movement amplitude, barrel activity was again greater after a twitch than a wake movement. We then inverted the analysis to assess the likelihood that increases in barrel activity were preceded within 500ms by whisker movements: at least 55% of barrel activity was attributable to sensoryfeedback from whisker movements. Finally, when periods with and without movement were compared, 70%-75% of barrel activity was movement related. These results confirm the importance of sensory feedbackfrom movements in driving activity in sensorimotor cortex and underscore the necessity of monitoring sleep-wake states to ensure accurate assessments of the contributions of the sensory periphery to activity in developing somatosensory cortex.