Vestibular Stimuli Research Articles

VHIT and fHIT in Patients With Migraine, Vestibular Migraine, and Persistent Postural-Perceptual Dizziness.

Impairment in the integration of different vestibular stimuli is the proposed mechanisms in vestibular migraine (VM). In this study, it was aimed to assess the vestibulo-ocular reflex (VOR) and dynamic visual acuity (DVA) in patients with VM and to compare the results with migraine without vestibular symptoms (MwoV), and persistent postural-perceptual dizziness (PPPD) to find out if there are discriminative differences and search for a correlation with the levels of anxiety. Twenty-two patients with MwoV, 23 patients with VM, 22 patients with PPPD, and 23 healthy controls (HC) were studied. Video head impulse test (vHIT) and functional head impulse test (fHIT) without and with an optokinetic background (OB) were performed. Percentage of correctly identified optotypes (CA%) was considered for the fHIT test. Beck anxiety inventory (BAI) was used to assess anxiety. Lateral canal vHIT gain of the patient groups were not different from the healthy controls (p > 0.05). fHIT and fHIT/OB CA% results of all patient groups were lower than the HC (p < 0.005), and VM patients had the lowest scores for both tests. BAI scores of the PPPD patients were the highest and a correlation between anxiety levels, and fHIT results could not be identified (p > 0.05). Prominent CA% drop by the use of an OB was the main finding in patients with VM. This discriminative feature was not correlated with anxiety scores. Difficulty in resolving the conflict between visual and vestibular inputs seem to be the underlying mechanism. 3 Laryngoscope, 2024.

Effectiveness of vestibular rehabilitation on postural balance in Parkinson’s disease: a systematic review and meta-analysis of randomized controlled trials

IntroductionPostural balance impairment can affect the quality of life of patients with Parkinson’s disease. Previous studies have described connections of the vestibular system with postural functions, suggesting a potential participation of the basal ganglia in receiving vestibular stimuli. This systematic review aims to summarize the evidence on the effectiveness of vestibular rehabilitation on postural balance in patients with Parkinson’s disease.MethodsA systematic review was conducted using the electronic databases: PubMed, Embase, Scopus and PEDro. The study selection was independently conducted by two reviewers, and disagreements were evaluated by a third reviewer. The included studies had no restrictions on publication dates or languages and the last update occurred in July 2023.ResultsFrom the 485 studies found in the searches, only 3 studies were deemed eligible for the systematic review involving a total of 130 participants. The Berg Balance Scale was described as the tool for evaluation of postural balance in all studies. The meta-analysis showed statistically significant results in favor of vestibular rehabilitation (MD = 5.35; 95% CI = 2.39, 8.31; P < 0.001), regardless of the stage of Parkinson’s disease. Although the effect size was suggested as a useful functional gain, the analysis was done with caution, as it only included 3 randomized controlled trials. The risk of bias using the RoB-2 was considered as being of “some concern” in all studies. Furthermore, the quality of the evidence based on the Grading of Recommendations Assessment Development and Evaluation system, produced by pooling the included studies was considered very low.ConclusionCompared to other interventions, vestibular rehabilitation has potential to assist the postural balance of patients with Parkinson’s disease. However, the very low quality of the evidence demonstrates uncertainty about the impact of this clinical practice. More robust studies are needed to confirm the benefits of this therapy in patients with Parkinson’s disease. This study was prospectively registered in PROSPERO: CRD42020210185.

Using principal component analysis to determine which vestibular stimuli provide best biomarkers for separating Alzheimer's from mixed Alzheimer's disease.

Alzheimer's disease (AD) is often mixed with cerebrovascular disease (AD-CVD). Heterogeneity of dementia etiology and the overlapping of neuropathological features of AD and AD-CVD make feature identification of the two challenging. Separation of AD from AD-CVD is important as the optimized treatment for each group may differ. Recent studies using vestibular responses recorded from electrovestibulography (EVestG™) have offered promising results for separating these two pathologies. An EVestG measurement records responses to several different physical stimuli (called tilts). In previous research, the number of EVestG features from different tilts was selected based on physiological intuition to classify AD from AD-CVD. As the number of potential characteristic features from all tilts can be very large, in this study, we used an algorithm based on principal component analysis (PCA) to rank the most effective vestibular stimuli for differentiating AD from AD-CVD. Analyses were performed on the EVestG signals of 28 individuals with AD and 24 with AD-CVD. The results of this study showed that tilts simulating the otolithic organs (utricle and saccule) generated the most characteristic features for separating AD from AD-CVD.

Nocturnal vestibular stimulation using a rocking bed improves a severe sleep disorder in a patient with mitochondrial disease.

Mitochondrial diseases are rare genetic disorders often accompanied by severe sleep disorders. We present the case of a 12-year-old boy diagnosed with a severe primary mitochondrial disease, exhibiting ataxia, spasticity, progressive external ophthalmoplegia, cardiomyopathy and severely disrupted sleep, but no cognitive impairment. Interestingly, his parents reported improved sleep during night train rides. Based on this observation, we installed a rocking bed in the patient's bedroom and performed different interventions, including immersive multimodal vestibular, kinesthetic and auditory stimuli, reminiscent of the sensory experiences encountered during train rides. Over a 5-month period, we conducted four 2-week nocturnal interventions, separated by 1-week washout phases, to determine the subjectively best-perceived stimulation parameters, followed by a final 4-week intervention using the optimal parameters. We assessed sleep duration and quality using the Mini Sleep Questionnaire, monitored pulse rate changes and used videography to document nocturnal interactions between the patient and caregivers. Patient-reported outcome measures, clinical examinations and personal outcomes of specific interests were used to document daytime sleepiness, restlessness, anxiety, fatigue, cognitive performance and physical posture. In the final 4-week intervention, sleep duration increased by 25%, required caregiver interactions reduced by 75%, and caregiving time decreased by 40%. Subjective fatigue, assessed by the Checklist Individual Strength, decreased by 40%, falling below the threshold of severe fatigue. Our study suggests that rocking beds could provide a promising treatment regime for selected patients with persistent severe sleep disorders. Further research is required to validate these findings in larger patient populations with sleep disorders and other conditions.

Sensorineural correlates of failed functional recovery after natural regeneration of vestibular hair cells in adult mice.

Vestibular hair cells (HCs) are mechanoreceptors that sense head motions by modulating the firing rate of vestibular ganglion neurons (VGNs), whose central processes project to vestibular nucleus neurons (VNNs) and cerebellar neurons. We explored vestibular function after HC destruction in adult Pou4f3+/DTR (DTR) mice, in which injections of high-dose (50 ng/g) diphtheria toxin (DT) destroyed most vestibular HCs within 2 weeks. At that time, DTR mice had lost the horizontal vestibulo-ocular reflex (aVORH), and their VNNs failed to upregulate nuclear cFos expression in response to a vestibular stimulus (centrifugation). Five months later, 21 and 14% of HCs were regenerated in utricles and horizontal ampullae, respectively. The vast majority of HCs present were type II. This degree of HC regeneration did not restore the aVORH or centrifugation-evoked cFos expression in VNNs. The failure to regain vestibular pathway function was not due to degeneration of VGNs or VNNs because normal neuron numbers were maintained after HC destruction. Furthermore, sinusoidal galvanic stimulation at the mastoid process evoked cFos protein expression in VNNs, indicating that VGNs were able to regulate VNN activity after HC loss. aVORH and cFos responses in VNNs were robust after low-dose (25 ng/g) DT, which compared to high-dose DT resulted in a similar degree of type II HC death and regeneration but spared more type I HCs in both organs. These findings demonstrate that having more type I HCs is correlated with stronger responses to vestibular stimulation and suggest that regenerating type I HCs may improve vestibular function after HC loss.

Analysis of Visual and Vestibular Information on Motion Sickness in Flight Simulation

Virtual reality (VR) is in its nascent technological advancement and market diffusion stages. Interestingly, the scientific exploration concerning the impact of non-isometric mapping disparities within visual–vestibular stimuli on motion sickness remains deficient. This investigation focuses on scrutinizing the visual–vestibular implications for motion sickness within the context of flight simulation. The developed motion platform, offering specific pitch and roll ranges of ±16 and ±17 degrees, respectively, was employed to induce varying ratios of simulated visual–vestibular cues. Involving a cohort of five participants, the study exposed them to two prevalent simulated mission profiles, subsequently assessing their motion sickness symptoms. Sixty responses were analyzed using the subjective assessment of the Simulator Sickness Questionnaire (SSQ). The findings reveal a reduction in cybersickness severity with congruent visual–vestibular stimuli in proportion to the variance observed among visual–vestibular coupling ratios. A comparative analysis of SSQ sub-categories demonstrates that disorientation holds the most significance in the hierarchy of motion sickness contributors, followed by oculomotor discomfort, with nausea manifesting as the least influential. This study can lead to situation awareness analysis by integrating VR-based flight-simulation setups in the formal training of pilots and UAV operators.

Head and vestibular kinematics during vertical semicircular canal impulses.

The video head impulse test (vHIT) is a common assessment of semicircular canal function during high-speed impulses. Reliability of the vHIT for assessing vertical semicircular canals is uncertain. Vertical head impulses require a complex head movement, making it difficult to isolate a single semicircular canal and interpret resulting eye rotations. The purpose of this study was to provide descriptive head kinematics and vestibular stimuli during vertical plane impulses to ultimately improve impulse delivery and interpretation of vHIT results for vertical semicircular canals. Six participants received right anterior (RA) and left posterior (LP) semicircular canal impulses. Linear displacements, rotational displacements, and rotational velocities of the head were measured. Peak velocities in semicircular canal planes and peak-to-peak gravitoinertial accelerations at the otolith organs were derived from head kinematics. The largest rotational velocities occurred in the target semicircular canal plane, with non-negligible velocities occurring in non-target planes. Larger vertical displacements and accelerations occurred on the right side of the head compared to the left for RA and LP impulses. These results provide a foundation for designing protocols to optimize stimulation applied to a singular vertical semicircular canal and for interpreting results from the vHIT for vertical semicircular canals.

Localization of Vestibular Cortex Using Electrical Cortical Stimulation: A Systematic Literature Review.

The vestibular system plays a fundamental role in body orientation, posture control, and spatial and body motion perception, as well as in gaze and eye movements. We aimed to review the current knowledge regarding the location of the cortical and subcortical areas, implicated in the processing of vestibular stimuli. The search was performed in PubMed and Scopus. We focused on studies reporting on vestibular manifestations after electrical cortical stimulation. A total of 16 studies were finally included. Two main types of vestibular responses were elicited, including vertigo and perception of body movement. The latter could be either rotatory or translational. Electrical stimulation of the temporal structures elicited mainly vertigo, while stimulation of the parietal lobe was associated with perceptions of body movement. Stimulation of the occipital lobe produced vertigo with visual manifestations. There was evidence that the vestibular responses became more robust with increasing current intensity. Low-frequency stimulation proved to be more effective than high-frequency in eliciting vestibular responses. Numerous non-vestibular responses were recorded after stimulation of the vestibular cortex, including somatosensory, viscero-sensory, and emotional manifestations. Newer imaging modalities such as functional MRI (fMRI), Positron Emission Tomography (PET), SPECT, and near infra-red spectroscopy (NIRS) can provide useful information regarding localization of the vestibular cortex.

Understanding the effects of stress on the P300 response during naturalistic simulation of heights exposure.

Stress is a prevalent bodily response universally experienced and significantly affects a person's mental and cognitive state. The P300 response is a commonly observed brain behaviour that provides insight into a person's cognitive state. Previous works have documented the effects of stress on the P300 behaviour; however, only a few have explored the performance in a mobile and naturalistic experimental setup. Our study examined the effects of stress on the human brain's P300 behaviour through a height exposure experiment that incorporates complex visual, vestibular, and proprioceptive stimuli. A more complex sensory environment could produce translatable findings toward real-world behaviour and benefit emerging technologies such as brain-computer interfaces. Seventeen participants experienced our experiment that elicited the stress response through physical and virtual height exposure. We found two unique groups within our participants that exhibited contrasting behavioural performance and P300 target reaction response when exposed to stressors (from walking at heights). One group performed worse when exposed to heights and exhibited a significant decrease in parietal P300 peak amplitude and increased beta and gamma power. On the other hand, the group less affected by stress exhibited a change in their N170 peak amplitude and alpha/mu rhythm desynchronisation. The findings of our study suggest that a more individualised approach to assessing a person's behaviour performance under stress can aid in understanding P300 performance when experiencing stress.

Unraveling the Twist: Spatial Navigational Challenges in Cervical Dystonia.

Cervical dystonia (CD) is an intricate neurological condition with motor and nonmotor symptoms. These include disruptions in visual perception, self-orientation, visual working memory, and vestibular functions. However, the specific impact of CD on perceiving self-motion direction, especially with isolated visual or vestibular stimuli, remains largely unexplored. This study aimed to examine the effects of CD on linear motion perception, hypothesizing impaired heading discrimination in both vestibular and visual tasks, and that such deficits correlate with the disease severity. We employed a cutting-edge motion platform to precisely control whole-body linear motion. Through repeated two-alternative forced-choice tasks, we assessed vestibular heading direction discrimination. Participants observed dynamic star clouds in immersive virtual reality and indicated their perceived self-motion direction, evaluating visual heading direction discrimination. Sensitivity to direction variations and response accuracy errors were analyzed using robust Gaussian cumulative distribution psychometric functions. Heading perception is impaired in individuals with CD, particularly evident in vestibular heading discrimination. CD severity correlated with elevated thresholds for both vestibular and visual heading discrimination. Surprisingly, lateralized CD did not introduce bias in either system, suggesting widespread disruption over localized effects. Contrary to previous beliefs, our findings challenge the idea that CD-related heading discrimination issues mainly arise from peripheral vestibular effects. Instead, abnormal proprioceptive input from dystonic neck muscles introduces noise into the central mechanism integrating visual, vestibular, and proprioceptive signals. These insights into spatial navigation deficits have implications for future CD research. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Visual–vestibular sensory integration during congruent and incongruent self-rotation percepts using caloric vestibular stimulation

Introduction: The present study sets out to determine which sensory system mostly influences self-motion perception when visual and vestibular cues are in conflict. We paired caloric vestibular stimulation that signaled motion in either the clockwise or counter-clockwise direction with a visual display that indicated self-rotation in either the same or opposite directions.Methods: In Experiment 1 (E1), caloric vestibular stimulation was used to produce vestibular circular vection. In Experiment 2 (E2), a virtual optokinetic drum was used to produce visual circular vection in a VR headset. Vection speed, direction, and duration were recorded using a potentiometer knob the participant controlled in E1 and E2. In Experiment 3 (E3), visual and vestibular stimuli were matched to be at approximately equal speeds across visual and vestibular modalities for each participant setting up Experiment 4 (E4). In E4, participants observed a moving visual pattern in a virtual reality (VR) headset while receiving caloric vestibular stimulation. Participants rotated the potentiometer knob while attending to visual–vestibular stimuli presentations to indicate their perceived circular vection. E4 had two conditions: 1) A congruent condition where calorics and visual display indicated circular vection in the same direction; 2) an incongruent condition where calorics and visual display indicated circular vection in opposite directions.Results and discussion: There were equal reports of knob rotation in the direction consistent with the visual and vestibular self-rotation direction in the incongruent condition of E4 across trials. There were no significant differences in knob rotation speed and duration in both conditions. These results demonstrate that the brain appears to weigh visual and vestibular cues equally during a visual–vestibular conflict of approximately equal speeds. These results are most consistent with the optimal cue integration hypothesis.

Electrophysiological Activity from the Eye Muscles, Cerebellum and Cerebrum During Reflexive (Classical Pavlovian) Versus Voluntary (Ivanov-Smolensky) Eye-Blink Conditioning

We report an experiment to investigate the role of the cerebellum and cerebrum in motor learning of timed movements. Eleven healthy human subjects were recruited to perform two experiments, the first was a classical eye-blink conditioning procedure with an auditory tone as conditional stimulus (CS) and vestibular unconditional stimulus (US) in the form of a double head-tap. In the second experiment, subjects were asked to blink voluntarily in synchrony with the double head-tap US preceded by a CS, a form of Ivanov-Smolensky conditioning in which a command or instruction is associated with the US. Electrophysiological recordings were made of extra-ocular EMG and EOG at infra-ocular sites (IO1/2), EEG from over the frontal eye fields (C3’/C4’) and from over the posterior fossa over the cerebellum for the electrocerebellogram (ECeG). The behavioural outcomes of the experiments showed weak reflexive conditioning for the first experiment despite the double tap but robust, well-synchronised voluntary conditioning for the second. Voluntary conditioned blinks were larger than the reflex ones. For the voluntary conditioning experiment, a contingent negative variation (CNV) was also present in the EEG leads prior to movement, and modulation of the high-frequency EEG occurred during movement. US-related cerebellar activity was prominent in the high-frequency ECeG for both experiments, while conditioned response-related cerebellar activity was additionally present in the voluntary conditioning experiment. These results demonstrate a role for the cerebellum in voluntary (Ivanov-Smolensky) as well as in reflexive (classical Pavlovian) conditioning.

Comparison of vestibular input statistics during natural activities and while piloting an aircraft.

The present study investigates the statistics and spectral content of natural vestibular stimuli experienced by healthy human subjects during three unconstrained activities. More specifically, we assessed how the characteristics of vestibular inputs are altered during the operation of a complex human-machine interface (a flight in a helicopter simulator) compared with more ecological tasks, namely a walk in an office space and a seated visual exploration task. As previously reported, we found that the power spectra of vestibular stimuli experienced during self-navigation could be modeled by two power laws but noted a potential effect of task intensity on the transition frequency between the two fits. In contrast, both tasks that required a seated position had power spectra that were better described by an inverted U shape in all planes of motion. Taken together, our results suggest that 1) walking elicits stereotyped vestibular inputs whose power spectra can be modeled by two power laws that intersect at a task intensity-dependent frequency; 2) body posture induces changes in the frequency content of vestibular information; 3) pilots tend to operate their aircraft in a way that does not generate highly nonecological vestibular stimuli; and 4) nevertheless, human-machine interfaces used as a means of manual navigation still impose some unnatural, contextual constraints on their operators.NEW & NOTEWORTHY Building upon previously published research, this study assesses and compares the vestibular stimuli experienced by healthy subjects in natural tasks and during the interaction with a complex machine: a helicopter simulator. Our results suggest the existence of an anatomical filter, meaning that body posture shapes vestibular spectral content. Our findings further indicate that operators control their machine within a constrained operating range such that they experience vestibular stimulations that are as ecological as possible.

Probabilistic integration of preceding responses explains response bias in perceptual decision making

Expectations of sensory information change not only how well but also what we perceive. Even in an unpredictable environment, the brain is by default constantly engaged in computing probabilities between sensory events. These estimates are used to generate predictions about future sensory events. Here, we investigated the predictability of behavioral responses using three different learning models in three different one-interval two-alternative forced choice experiments with either auditory, vestibular, or visual stimuli. Results indicate that recent decisions, instead of the sequence of generative stimuli, cause serial dependence. By bridging the gap between sequence learning and perceptual decision making, we provide a novel perspective on sequential choice effects. We propose that serial biases reflect the tracking of statistical regularities of the decision variable, offering a broader understanding of this phenomenon.

The Nature and Origin of Synaptic Inputs to Vestibulospinal Neurons in the Larval Zebrafish.

Vestibulospinal neurons integrate sensed imbalance to regulate postural reflexes. As an evolutionarily conserved neural population, understanding their synaptic and circuit-level properties can offer insight into vertebrate antigravity reflexes. Motivated by recent work, we set out to verify and extend the characterization of vestibulospinal neurons in the larval zebrafish. Using current-clamp recordings together with stimulation, we observed that larval zebrafish vestibulospinal neurons are silent at rest, yet capable of sustained spiking following depolarization. Neurons responded systematically to a vestibular stimulus (translation in the dark); responses were abolished after chronic or acute loss of the utricular otolith. Voltage-clamp recordings at rest revealed strong excitatory inputs with a characteristic multimodal distribution of amplitudes, as well as strong inhibitory inputs. Excitatory inputs within a particular mode (amplitude range) routinely violated refractory period criteria and exhibited complex sensory tuning, suggesting a nonunitary origin. Next, using a unilateral loss-of-function approach, we characterized the source of vestibular inputs to vestibulospinal neurons from each ear. We observed systematic loss of high-amplitude excitatory inputs after utricular lesions ipsilateral, but not contralateral, to the recorded vestibulospinal neuron. In contrast, while some neurons had decreased inhibitory inputs after either ipsilateral or contralateral lesions, there were no systematic changes across the population of recorded neurons. We conclude that imbalance sensed by the utricular otolith shapes the responses of larval zebrafish vestibulospinal neurons through both excitatory and inhibitory inputs. Our findings expand our understanding of how a vertebrate model, the larval zebrafish, might use vestibulospinal input to stabilize posture. More broadly, when compared with recordings in other vertebrates, our data speak to conserved origins of vestibulospinal synaptic input.

Both whole-body rotation and visual flow induce cardiovascular autonomic response in human, but visual response is overridden by vestibular stimulation

While the influence of the vestibular and extra-vestibular gravity signals on the cardiovascular system has been demonstrated, there is little evidence that visual stimuli can trigger cardiovascular responses. Furthermore, there is no evidence of interaction between visual and vestibular signals in autonomic control, as would be expected since they are highly integrated. The present study explored the cardiovascular responses to vestibular and visual stimuli in normal subjects. We hypothesized that the visual stimuli would modify the cardiovascular response to vestibular stimulation, especially when the latter is ambiguous with respect to gravity. Off-Vertical-Axis-Rotation (OVAR) was used to stimulate vestibular and extra-vestibular receptors of gravity in 36 healthy young adults while virtual reality was used for visual stimulation. Arterial pressure (AP), respiratory rate and ECG were measured. The analysis accounted for the respiratory modulation of AP and heart rate (HR). Vestibular stimulation by OVAR was shown to modulate both mean arterial pressure (MAP) and HR, while the visual stimulation was significantly affecting HR modulation, but not MAP. Moreover, the specific visual effect was present only when the subjects were not in rotation. Therefore, visual stimulation is able to modulate the heart rate, but is overridden by vestibular stimulation due to real movement.

Diverse effects of gaze direction on heading perception in humans.

Gaze change can misalign spatial reference frames encoding visual and vestibular signals in cortex, which may affect the heading discrimination. Here, by systematically manipulating the eye-in-head and head-on-body positions to change the gaze direction of subjects, the performance of heading discrimination was tested with visual, vestibular, and combined stimuli in a reaction-time task in which the reaction time is under the control of subjects. We found the gaze change induced substantial biases in perceived heading, increased the threshold of discrimination and reaction time of subjects in all stimulus conditions. For the visual stimulus, the gaze effects were induced by changing the eye-in-world position, and the perceived heading was biased in the opposite direction of gaze. In contrast, the vestibular gaze effects were induced by changing the eye-in-head position, and the perceived heading was biased in the same direction of gaze. Although the bias was reduced when the visual and vestibular stimuli were combined, integration of the 2 signals substantially deviated from predictions of an extended diffusion model that accumulates evidence optimally over time and across sensory modalities. These findings reveal diverse gaze effects on the heading discrimination and emphasize that the transformation of spatial reference frames may underlie the effects.

Expression of a Form of Cerebellar Motor Memory Requires Learned Alterations to the Activity of Inhibitory Molecular Layer Interneurons.

Procedural memories formed in the cerebellum in response to motor errors depend on changes to Purkinje cell (PC) spiking patterns that correct movement when the erroneous context is repeated. Because molecular layer interneurons (MLIs) inhibit PCs, learning-induced changes to MLI output may participate in reshaping PC spiking patterns. However, it remains unclear whether error-driven learning alters MLI activity and whether such changes are necessary for the memory engram. We addressed this knowledge gap by measuring and manipulating MLI activity in the flocculus of both sexes of mice before and after vestibulo-ocular reflex (VOR) adaptation. We found that MLIs are activated during vestibular stimuli and that their population response exhibits a phase shift after the instantiation of gain-increase VOR adaptation, a type of error-driven learning thought to require climbing-fiber-mediated instructive signaling. Although acute optogenetic suppression of MLI activity did not affect baseline VOR performance, it negated the expression of gain-increase learning, demonstrating a specific role of MLI activity changes in motor memory expression. This effect was transitory; after a multiday consolidation period, the expression of VOR gain-increase learning was no longer sensitive to MLI activity suppression. Together, our results indicate that error-driven alteration of MLI activity is necessary for labile, climbing-fiber-induced motor memory expression.SIGNIFICANCE STATEMENT In the cerebellum, motor learning induces an associative memory of the sensorimotor context of an erroneous movement that, when recalled, results in a new pattern of output that improves subsequent trials of performance. Our study shows that error-driven motor learning induces changes to the activity pattern of cerebellar molecular layer interneurons (MLIs) and that this new pattern of activity is required to express the corrective motor memory.

Processing of sensory, painful and vestibular stimuli in the thalamus

ObjectivesThe thalamus plays an important role in the mediation and integration of various stimuli (e.g., somatosensory, pain, and vestibular). Whether a stimulus-specific and topographic organization of the thalamic nuclei exists is still unknown. The aim of our study was to define a functional, in vivo map of multimodal sensory processing within the human thalamus.MethodsTwenty healthy individuals (10 women, 21–34 years old) participated. Defined sensory stimuli were applied to both hands (innocuous touch, mechanical pain, and heat pain) and the vestibular organ (galvanic stimulation) during 3 T functional MRI.ResultsBilateral thalamic activations could be detected for touch, mechanical pain, and vestibular stimulation within the left medio-dorsal and right anterior thalamus. Heat pain did not lead to thalamic activation at all. Stimuli applied to the left body side resulted in stronger activation patterns. Comparing an early with a late stimulation interval, the mentioned activation patterns were far more pronounced within the early stimulation interval.ConclusionsThe right anterior and ventral-anterior nucleus and the left medio-dorsal nucleus appear to be important for the processing of multimodal sensory information. In addition, galvanic stimulation is processed more laterally compared to mechanical pain. The observed changes in activity within the thalamic nuclei depending on the stimulation interval suggest that the stimuli are processed in a thalamic network rather than a distinct nucleus. In particular, the vestibular network within the thalamus recruits bilateral nuclei, rendering the thalamus an important integrative structure for vestibular function.

ANALYSIS OF SCIENTIFIC RESEARCH ON THE SENSIMOTOR DEVELOPMENT OF CHILDREN WITH DISORDERS OF INTELLECTUAL DEVELOPMENT

The article provides a theoretical analysis of research on the problem of sensorimotor development with children with violation of intellectual development. Theoretical aspects of sensorimotor development of children with intellectual disabilities in the following areas are considered: vestibular-postural reactions and bilateral coordination. Motor mechanisms affect the general development of the child, his ability to work and master the curriculum. Studies have shown the effect of physical activity on mental activity and academic performance. Imperfections of the motor sphere of children with PIR are revealed. Children's gait is unstable, movements are chaotic, poorly coordinated, poorly regulated muscular effort, impaired visual-motor coordination, inability to imitate, underdevelopment of differentiated finger movements. The disadvantages of arbitrary movements are pronounced. Theoretical analysis of scientific research on the role of the central nervous system in the construction of movements. Spinal cord, medulla, diencephalon, cerebellum, large hemispheres perform their functions. Simple movements (reflective) provide normal performance of more complex movements performed due to the lower parts of the central nervous system (spinal, medulla, midbrain). More complex postures are regulated by the activity of the midbrain, the vestibular system, which obey the cerebellum. The cerebellum coordinates the proportionality of movement. To perform movement in space, it is necessary to combine all types of sensitive sphere (afferentation). This process occurs at the level of the diencephalon and subcortical nuclei. It is proved that part of the vestibular signals must be registered and modulated by the brain. The lack of modulation of vestibular stimuli will be noticeable in bilateral reactions, coordination of the two sides of the body. The postural response may go unnoticed because it is difficult for the child to adopt a particular posture. Sensorimotor development affects the functioning of the body of a child with violation of intellectual development.