scholarly journals Learned Overweight Internal Model Can Be Activated to Maintain Equilibrium When Tactile Cues Are Uncertain: Evidence From Cortical and Behavioral Approaches

2021 ◽  
Vol 15 ◽  
Author(s):  
Olivia Lhomond ◽  
Benjamin Juan ◽  
Theo Fornerone ◽  
Marion Cossin ◽  
Dany Paleressompoulle ◽  
...  
Keyword(s):  
Internal Model ◽  
Tactile Stimulation ◽  
Balance Control ◽  
Load Condition ◽  
Internal Models ◽  
Support Surface ◽  
Extra Weight ◽  
The Right ◽  
The Brain ◽  
Load Conditions

Human adaptive behavior in sensorimotor control is aimed to increase the confidence in feedforward mechanisms when sensory afferents are uncertain. It is thought that these feedforward mechanisms rely on predictions from internal models. We investigate whether the brain uses an internal model of physical laws (gravitational and inertial forces) to help estimate body equilibrium when tactile inputs from the foot sole are depressed by carrying extra weight. As direct experimental evidence for such a model is limited, we used Judoka athletes thought to have built up internal models of external loads (i.e., opponent weight management) as compared with Non-Athlete participants and Dancers (highly skilled in balance control). Using electroencephalography, we first (experiment 1) tested the hypothesis that the influence of tactile inputs was amplified by descending cortical efferent signals. We compared the amplitude of P1N1 somatosensory cortical potential evoked by electrical stimulation of the foot sole in participants standing still with their eyes closed. We showed smaller P1N1 amplitudes in the Load compared to No Load conditions in both Non-Athletes and Dancers. This decrease neural response to tactile stimulation was associated with greater postural oscillations. By contrast in the Judoka’s group, the neural early response to tactile stimulation was unregulated in the Load condition. This suggests that the brain can selectively increase the functional gain of sensory inputs, during challenging equilibrium tasks when tactile inputs were mechanically depressed by wearing a weighted vest. In Judokas, the activation of regions such as the right posterior inferior parietal cortex (PPC) as early as the P1N1 is likely the source of the neural responses being maintained similar in both Load and No Load conditions. An overweight internal model stored in the right PPC known to be involved in maintaining a coherent representation of one’s body in space can optimize predictive mechanisms in situations with high balance constraints (Experiment 2). This hypothesis has been confirmed by showing that postural reaction evoked by a translation of the support surface on which participants were standing wearing extra-weight was improved in Judokas.

scholarly journals Internal models for interpreting neural population activity during sensorimotor control

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Matthew D Golub ◽  
Byron M Yu ◽  
Steven M Chase
Keyword(s):  
Internal Model ◽  
Sensory Information ◽  
Internal Models ◽  
Neural Population ◽  
Prior Beliefs ◽  
Population Activity ◽  
Motor Commands ◽  
Machine Interface ◽  
The Brain ◽  
Neural Population Activity

To successfully guide limb movements, the brain takes in sensory information about the limb, internally tracks the state of the limb, and produces appropriate motor commands. It is widely believed that this process uses an internal model, which describes our prior beliefs about how the limb responds to motor commands. Here, we leveraged a brain-machine interface (BMI) paradigm in rhesus monkeys and novel statistical analyses of neural population activity to gain insight into moment-by-moment internal model computations. We discovered that a mismatch between subjects’ internal models and the actual BMI explains roughly 65% of movement errors, as well as long-standing deficiencies in BMI speed control. We then used the internal models to characterize how the neural population activity changes during BMI learning. More broadly, this work provides an approach for interpreting neural population activity in the context of how prior beliefs guide the transformation of sensory input to motor output.

scholarly journals Contextual cuing contributes to the independent modification of multiple internal models for vocal control

2011 ◽  
Vol 105 (5) ◽  
pp. 2448-2456 ◽  
Author(s):  
Dwayne Keough ◽  
Jeffery A. Jones
Keyword(s):  
Auditory Feedback ◽  
Internal Model ◽  
Sensory Feedback ◽  
Motor Command ◽  
Internal Models ◽  
Motor Commands ◽  
Arm Reaching ◽  
Vocal Control ◽  
Vocal Productions ◽  
The Brain

Research on the control of visually guided limb movements indicates that the brain learns and continuously updates an internal model that maps the relationship between motor commands and sensory feedback. A growing body of work suggests that an internal model that relates motor commands to sensory feedback also supports vocal control. There is evidence from arm-reaching studies that shows that when provided with a contextual cue, the motor system can acquire multiple internal models, which allows an animal to adapt to different perturbations in diverse contexts. In this study we show that trained singers can rapidly acquire multiple internal models regarding voice fundamental frequency ( F0). These models accommodate different perturbations to ongoing auditory feedback. Participants heard three musical notes and reproduced each one in succession. The musical targets could serve as a contextual cue to indicate which direction (up or down) feedback would be altered on each trial; however, participants were not explicitly instructed to use this strategy. When participants were gradually exposed to altered feedback adaptation was observed immediately following vocal onset. Aftereffects were target specific and did not influence vocal productions on subsequent trials. When target notes were no longer a contextual cue, adaptation occurred during altered feedback trials and evidence for trial-by-trial adaptation was found. These findings indicate that the brain is exceptionally sensitive to the deviations between auditory feedback and the predicted consequence of a motor command during vocalization. Moreover, these results indicate that, with contextual cues, the vocal control system may maintain multiple internal models that are capable of independent modification during different tasks or environments.

scholarly journals Individualised dynamic internal representations from response times

2020 ◽  
Author(s):  
Balázs Török ◽  
Dávid G. Nagy ◽  
Mariann M. Kiss ◽  
Karolina Janacsek ◽  
Dezső Németh ◽  
...  
Keyword(s):  
Internal Model ◽  
Dynamic Models ◽  
Response Times ◽  
Learning Task ◽  
Internal Models ◽  
Learning Curves ◽  
Task Demands ◽  
Environmental Data ◽  
Trial Basis ◽  
The Right

AbstractInternal models are central to understand how human behaviour is adapted to the statistics of, potentially limited, environmental data. Such internal models contribute to rich and flexible inferences and thus adapt to varying task demands. However, the right internal model is not available for observers, instead approximate and transient internal models are recruited. To understand learning and momentary inferences, we need tools to characterise these approximate, yet rich and potentially dynamic models through behaviour. We used a combination of non-parametric Bayesian methods and probabilistic programming to infer individualised internal models from human response times in an implicit visuomotor learning task. Using this Cognitive Tomography approach we predict response times on a trial-by-trial basis and validate the internal model by showing its invariance across tasks and sensitivity to stimulus statistics. By tracking the performance of participants for multiple days, individual learning curves revealed transient subjective internal models and pronounced inductive biases.

The brain structure and neurosecretory cells of noctuid moth Anadevidia peponis: Noctuidae

1990 ◽  
Vol 48 (3) ◽  
pp. 436-437
Author(s):  
M. Sato ◽  
Y. Ogawa ◽  
M. Sasaki ◽  
T. Matsuo
Keyword(s):  
Biological Clock ◽  
Virgin Female ◽  
Basic Structure ◽  
Fixed Time ◽  
Neurosecretory Cells ◽  
Nerve Cells ◽  
Noctuid Moth ◽  
The Right ◽  
20 Nm ◽  
The Brain

A virgin female of the noctuid moth, a kind of noctuidae that eats cucumis, etc. performs calling at a fixed time of each day, depending on the length of a day. The photoreceptors that induce this calling are located around the neurosecretory cells (NSC) in the central portion of the protocerebrum. Besides, it is considered that the female’s biological clock is located also in the cerebral lobe. In order to elucidate the calling and the function of the biological clock, it is necessary to clarify the basic structure of the brain. The observation results of 12 or 30 day-old noctuid moths showed that their brains are basically composed of an outer and an inner portion-neural lamella (about 2.5 μm) of collagen fibril and perineurium cells. Furthermore, nerve cells surround the cerebral lobes, in which NSCs, mushroom bodies, and central nerve cells, etc. are observed. The NSCs are large-sized (20 to 30 μm dia.) cells, which are located in the pons intercerebralis of the head section and at the rear of the mushroom body (two each on the right and left). Furthermore, the cells were classified into two types: one having many free ribosoms 15 to 20 nm in dia. and the other having granules 150 to 350 nm in dia. (Fig. 1).

ASSESSMENT OF PHYSIOLOGICAL PARAMETERS OF THE TRIGEMINAL AND COCHLEOVESTIBULAR SYSTEMS IN TEMPOROMANDIBULAR JOINT PAIN DYSFUNCTION

2020 ◽  
Vol 17 (2) ◽  
pp. 110-120
Author(s):  
N.D. Sorokina ◽  
◽  
L.R. Shahalieva ◽  
S.S. Pertsov ◽  
L.V. Polma ◽  
...  
Keyword(s):  
Nervous System ◽  
Evoked Potentials ◽  
Temporomandibular Joint ◽  
Differential Diagnostics ◽  
Autonomous Nervous System ◽  
Dental Diseases ◽  
Grade Ii ◽  
The Right ◽  
Distal Occlusion ◽  
The Brain

One of the most common causes of chronic pain in the facial region, including in the trigeminal nerve link, which is not associated with dental diseases, is pain dysfunction of the temporomandibular joint. At the same time, there is evidence in the literature that there are relationships between pain dysfunction of the temporomandibular joint, abnormal occlusion, cervical-muscular tonic phenomena, postural disorders, dysfunction of the Autonomous nervous system and cochleovestibular manifestations. At the same time, neurophysiological indicators of functional disorders in the maxillofacial region and intersystem interactions in pain dysfunction of the temporomandibular joint are insufficiently studied.Goal. The aim of the work is to evaluate the neurophysiological features of trigeminal afferentation in terms of trigeminal somatosensory evoked potentials (TSWP) and the auditory conducting system of the brain in terms of acoustic stem evoked potentials (ASVP) in distal occlusion of the dentition with pain dysfunction of the temporomandibular joint (TMJ) in comparison with physiological occlusion in students 18-21 years old. Material and methods. The main study included 41 students with distal occlusion (21 girls and 20 boys), (grade II Engl, symmetrically right and left in 14 people, and grade II Engl on the left and grade I on the right in 12 people, grade I on the left and grade II on the right in 15 people). All respondents with distal occlusion and who were practically healthy signed an informed consent to participate in the study. We used complex orthodontic methods of examination, subjective degree of severity and intensity of pain in the TMJ, assessment of the Autonomous nervous system (samples and tests), and neurophysiological methods for assessing TSVP and ASVP. Results. Significant differences in ASEP parameters were found in the group of respondents with distal occlusion in the form of a decrease in the latency period of peak I, III, and V compared to physiological occlusion, that correlated with the subjective assessment (in points) of cochleovestibular disorders. According to the TSVP study, a decrease in the duration of latent periods was found, which indicates an increased excitability of non-specific brain stem structures at the medullo-ponto-mesencephalic level compared to the control group. Conclusions. The results obtained are supposed to be used for differential diagnostics, including such dental diseases as TMJ pain dysfunction, occlusion abnormalities accompanied by pain syndrome. Additional functional diagnostics of multi-modal VP of the brain (acoustic evoked potentials, trigeminal evoked potentials) can be performed in conjunction with indicators of autonomic nervous system dysfunction, with parameters of severity of clinical symptoms of cochleovestibular disorders, musculoskeletal dysfunction the maxillofacial area, with indicators of pain, which will determine the tactics and effectiveness of subsequent treatment.

scholarly journals RONC-26. A CASE OF RADIATION NECROSIS OF THE CEREBELLUM 16 YEARS AFTER CHEMORADIOTHERAPY FOR MEDULLOBLASTOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii460-iii460
Author(s):  
Mayuko Miyata ◽  
Masahiro Nonaka ◽  
Akio Asai
Keyword(s):  
Radiation Necrosis ◽  
Tumor Resection ◽  
Pathological Examination ◽  
Secondary Cancer ◽  
Brain Necrosis ◽  
Cerebellar Medulloblastoma ◽  
Cerebellar Peduncle ◽  
The Right ◽  
The Brain

Abstract BACKGROUND If new lesions are observed during follow-up of the malignant tumor after treatment, it is difficult to distinguish whether the tumor is a recurrent lesion, secondary cancer, or radiation necrosis of the brain. We have encountered a patient with symptomatic radiation necrosis of the cerebellum 16 years after treatment of medulloblastoma. CASE PRESENTATION: A 24-year-old man who had received a tumor resection and chemoradiotherapy for cerebellar medulloblastoma at the age of 8 presented with dizziness. For the past 16 years, there was no recurrence of the tumor. He subsequently underwent MRI scan, and T1-Gd image showed enhanced lesion in the right cerebellar peduncle. Cerebrospinal fluid cytology analysis was negative for tumor. We suspected tumor reccurence or secondary cancer, and performed lesion biopsy. The result of the pathological examination was radiation necrosis of the cerebellum. DISCUSSION: The interval of radiation necrosis of the brain and radiotherapy can vary from months to more than 10 years. So, whenever a new lesion is identified, radiation brain necrosis must be envisioned. According to guidelines in Japan, there is no absolute examination for discriminating tumor recurrence from radiation brain necrosis and diagnosis by biopsy may be required. CONCLUSION We experienced a case of symptomatic radiation necrosis of the cerebellum 16 years after treatment. In patients showing new lesion after long periods of time, the possibility of radiation necrosis to be considered.

Neurospect Findings in Patients Exposed to Neurotoxic Chemicals

1994 ◽  
Vol 10 (4-5) ◽  
pp. 561-571
Author(s):  
Gunnar Heuser ◽  
Ismael Mena ◽  
Francisca Alamos
Keyword(s):  
Elderly Patients ◽  
Qualitative Analysis ◽  
Right Hemisphere ◽  
Young Patients ◽  
Chronic Fatigue ◽  
Psychiatric Symptomatology ◽  
Elderly Individuals ◽  
Parietal Lobes ◽  
The Right ◽  
The Brain

Exposures to neurotoxic chemicals such as pesticides, glues, solvents, etc. are known to induce neurologic and psychiatric symptomatology. We report on 41 patients 16 young patients (6 males, 10 females, age 34 8 yrs.) and 25 elderly patients (9 males, 16 females, age 55 7 yrs). Fifteen of them were exposed to pesticides, and 29 to solvents. They were studied with quantitative and qualitative analysis of regional cerebral bood flow (rCBF), performed with 30 mCi of Xe-133 by inhalation, followed by 30 mCi of Tc-HMPAO given intravenously. Imaging was performed with a brain dedicated system, distribution of rCBF was assessed with automatic ROI definition, and HMPAO was normalized to maximal pixel activity in the brain. Results of Xe rCBF are expressed as mean and S.D. in ml/min/100g, and HMPAO as mean and S.D. uptake per ROI, and compared with age-matched controls 10 young and 20 elderly individuals. Neurotoxics HMPAO Uptake Young Elderly R. Orbital frontal R. Dorsal frontal .70 .66 p < 0.05 R. Temporal .64 p < 0.001 R. Parietal .66 .66 We conclude that patients exposed to chemicals present with diminished CBF, worse in the right hemisphere, with random presentation of areas of hypoperfusion, more prevalent in the dorsal frontal and parietal lobes. These findings are significantly different from observations in patients with chronic fatigue and depression, suggesting primary cortical effect, possibly due to a vasculitis process.

Choroidal metastases: case report and review

2020 ◽  
pp. 1-7
Author(s):  
Victor Duque ◽  
Carolina de la Pinta ◽  
Ciriaco Corral ◽  
Carmen Vallejo ◽  
Margarita Martin ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Side Effects ◽  
External Beam Radiotherapy ◽  
Choroidal Metastasis ◽  
Good Visual Acuity ◽  
Good Local Control ◽  
Radiological Response ◽  
The Right ◽  
The Brain

Abstract Introduction: Choroidal metastases are the most frequent intraocular secondary tumours, with a prevalence of 2–7% according to the literature. Our aim was to review a clinical case of choroidal metastasis. We present a case of a 63-year-old male patient diagnosed in 2018 with lung adenocarcinoma cT4N0M1. The patient had three metastases in the brain, which were successfully treated with radiosurgery (RS). The patient was treated with chemotherapy with pemetrexed–cisplatin schedule. Five months after diagnosis, the patient presented with decreased vision in the right eye. After ophthalmologic evaluation, he was diagnosed with a right choroidal metastasis, which was treated with external beam radiotherapy with 20 Gy in five fractions, resulting in improved visual acuity and a complete clinical and radiological response. The patient took part in a clinical trial that continued with systemic chemotherapy. Twenty-two months after radiotherapy to the eye, the patient has good visual acuity without any side effects. Conclusions: Choroidal metastasis treated with radiotherapy achieves good local control, with limited side effects, allowing an improvement in visual acuity and consequently, an improvement in the patient´s quality of life.

scholarly journals Non-Stationary Model of Cerebral Oxygen Transport with Unknown Sources

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 910
Author(s):  
Andrey Kovtanyuk ◽  
Alexander Chebotarev ◽  
Varvara Turova ◽  
Irina Sidorenko ◽  
Renée Lampe
Keyword(s):  
Inverse Problem ◽  
Oxygen Transport ◽  
Model Parameters ◽  
Cerebral Oxygen ◽  
System Of Equations ◽  
Blood Oxygen ◽  
Stationary Model ◽  
Average Oxygen Concentration ◽  
The Right ◽  
The Brain

An inverse problem for a system of equations modeling oxygen transport in the brain is studied. The problem consists of finding the right-hand side of the equation for the blood oxygen transport, which is a linear combination of given functionals describing the average oxygen concentration in the neighborhoods of the ends of arterioles and venules. The overdetermination condition is determined by the values of these functionals evaluated on the solution. The unique solvability of the problem is proven without any smallness assumptions on the model parameters.

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