scholarly journals Active neural coordination of motor behaviors with internal states

2021 ◽  
Author(s):  
Yisi S. Zhang ◽  
Daniel Y. Takahashi ◽  
Ahmed El Hady ◽  
Diana A. Liao ◽  
Asif A. Ghazanfar
Keyword(s):  
Motor Behavior ◽  
Cardiac Activity ◽  
Motor Behaviors ◽  
Spontaneous Movements ◽  
Causal Ordering ◽  
Heart Rate Fluctuations ◽  
Internal States ◽  
Network States ◽  
Medial Section ◽  
The Brain

AbstractThe brain continuously coordinates skeletomuscular movements with internal physiological states like arousal, but how is this coordination achieved? One possibility is that brain simply reacts to changes in external and/or internal signals. Another possibility is that it is actively coordinating both external and internal activities. We used functional ultrasound imaging to capture a large medial section of the brain, including multiple cortical and subcortical areas, in marmoset monkeys while monitoring their spontaneous movements and cardiac activity. By analyzing the causal ordering of these different time-series, we found that information flowing from the brain to movements and heart rate fluctuations were significantly greater than in the opposite direction. The brain areas involved in this external versus internal coordination were spatially distinct but also extensively interconnected. Temporally, the brain alternated between network states for this regulation. These findings suggest that the brain’s dynamics actively and efficiently coordinate motor behavior with internal physiology.

scholarly journals Output Units of Motor Behavior: An Experimental and Modeling Study

2000 ◽  
Vol 12 (1) ◽  
pp. 78-97 ◽  
Author(s):  
E. P. Loeb ◽  
S. F. Giszter ◽  
P. Saltiel and E. Bizzi ◽  
F. A. Mussa-Ivaldi
Keyword(s):  
Motor Control ◽  
Common Property ◽  
Motor Behavior ◽  
Muscle Synergies ◽  
Force Output ◽  
Time Dynamics ◽  
Motor Behaviors ◽  
Distinct Property ◽  
Small Set ◽  
The Brain

Cognitive approaches to motor control typically concern sequences of discrete actions without taking into account the stunning complexity of the geometry and dynamics of the muscles. This begs the question: Does the brain convert the intricate, continuous-time dynamics of the muscles into simpler discrete units of actions, and if so, how? One way for the brain to form discrete units of behavior from muscles is through the synergistic co-activation of muscles. While this possibility has long been known, the composition of potential muscle synergies has remained elusive. In this paper, we have focused on a method that allowed us to examine and compare the limb stabilization properties of all possible muscle combinations. We found that a small set (as few as 23 out of 65,536) of all possible combinations of 16 limb muscles are robust with respect to activation noise: these muscle combinations could stabilize the limb at predictable, restricted portions of the workspace in spite of broad variations in the force output of their component muscles. The locations at which the robust synergies stabilize the limb are not uniformly distributed throughout the leg's workspace, but rather, they cluster at four workspace areas. The simulated robust synergies are similar to the actual synergies we have previously found to be generated by activation of the spinal cord. Thus, we have developed a new analytical method that enabled us to select a few muscle synergies with interesting properties out of the set of possible muscle combinations. Beyond this, the identification of robustness as a common property of the synergies in simple motor behaviors will open the way to the study of dynamic stability, which is an important and distinct property of the vertebrate motor-control system.

Lack of Adaptation to Random Conflicting Force Fields of Variable Magnitude

2007 ◽  
Vol 97 (1) ◽  
pp. 738-745 ◽  
Author(s):  
Rahul Gupta ◽  
James Ashe
Keyword(s):  
Motor Behavior ◽  
Force Fields ◽  
Human Subjects ◽  
Large Body ◽  
Internal Models ◽  
Limited Capacity ◽  
Contextual Cues ◽  
Motor Behaviors ◽  
Extended Practice ◽  
The Brain

The concept of internal models has been used to explain how the brain learns and stores a variety of motor behaviors. A large body of work has shown that conflicting internal models could not be learned simultaneously; this suggests either a limited capacity or the unstable nature of short-term motor memories. However, it has been recently shown that multiple conflicting internal models of motor behavior could be acquired simultaneously if associated with appropriate contextual cues and random presentations. We re-examined this issue in a more complex environment in which the magnitude of the conflicting fields could vary randomly. Human subjects failed to show any evidence of learning the force fields themselves or the magnitude of the forces experienced, even with extended practice. Subjects did adapt to the applied perturbation when the field strength was kept constant but still did not form internal models. Our results show that neither random presentation nor specific contextual cues are sufficient for learning conflicting internal models when the magnitude of the forces is also unpredictable. The data suggest that multiple conflicting internal models cannot be learned in all environments, and provide support for the unstable nature or limited capacity of motor memories.

scholarly journals Movement errors during skilled motor performance engage distinct prediction error mechanisms

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Ella Gabitov ◽  
Ovidiu Lungu ◽  
Geneviève Albouy ◽  
Julien Doyon
Keyword(s):  
Prediction Error ◽  
Motor Behavior ◽  
Prediction Errors ◽  
Unexpected Events ◽  
Sensorimotor Network ◽  
Motor Behaviors ◽  
Neural Computations ◽  
Adaptive Processes ◽  
Reward Valuation ◽  
The Brain

AbstractThe brain detects deviations from intended behaviors by estimating the mismatch between predicted and actual outcomes. Axiomatic to these computations are salience and valence prediction error signals, which alert the brain to the occurrence and value of unexpected events. Despite the theoretical assertion of these prediction error signals, it is unknown whether and how brain mechanisms underlying their computations support error processing during skilled motor behavior. Here we demonstrate, with functional magnetic resonance imaging, that internal detection, i.e., without externally-provided feedback, of self-generated movement errors evokes instantaneous activity increases within the salience network and delayed lingering decreases within the nucleus accumbens – a key structure in the reward valuation pathway. A widespread suppression within the sensorimotor network was also observed. Our findings suggest that neural computations of salience and valence prediction errors during skilled motor behaviors operate on different time-scales and, therefore, may contribute differentially to immediate and longer-term adaptive processes.

scholarly journals Hypothalamic dopamine neurons control sensorimotor behavior by modulating brainstem premotor nuclei

2020 ◽  
Author(s):  
Joshua P. Barrios ◽  
Wei-Chun Wang ◽  
Roman England ◽  
Erica Reifenberg ◽  
Adam D. Douglass
Keyword(s):  
Sensorimotor Integration ◽  
Motor Behavior ◽  
Third Ventricle ◽  
Dopamine Neurons ◽  
Preoptic Nucleus ◽  
Anatomy And Physiology ◽  
Motor Behaviors ◽  
Hypothalamic Nuclei ◽  
The Brain ◽  
Hypothalamic Dopamine

SummaryDopamine (DA)-producing neurons are critically involved in the production of motor behaviors in multiple circuits that are conserved from basal vertebrates to mammals. While there is increasing evidence that DA neurons in the hypothalamus play a locomotor role, their precise contributions to behavior and the circuit mechanisms by which they are achieved remain unclear. Here we demonstrate that tyrosine hydroxylase 2-expressing (th2+) DA neurons in the zebrafish hypothalamus fire phasic bursts of activity to acutely promote swimming and modulate audiomotor behaviors on fast timescales. Their anatomy and physiology reveal two distinct functional DA modules within the hypothalamus. The first comprises an interconnected set of cerebrospinal fluid-contacting DA nuclei surrounding the third ventricle, which lack distal projections outside of the hypothalamus and influence locomotion through unknown means. The second includes neurons in the preoptic nucleus, which send long-range projections to targets throughout the brain, including the mid- and hindbrain, where they activate premotor circuits involved in swimming and sensorimotor integration. These data suggest a broad regulation of motor behavior by DA neurons within multiple hypothalamic nuclei and elucidate a novel functional mechanism for the preoptic DA neurons in the initiation of movement.

scholarly journals Millimeter (MM) wave and microwave frequency radiation produce deeply penetrating effects: the biology and the physics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Martin L. Pall
Keyword(s):  
Magnetic Fields ◽  
Electric Fields ◽  
Cardiac Activity ◽  
Maximum Level ◽  
Voltage Sensor ◽  
The Body ◽  
Time Varying ◽  
The Brain ◽  
Mm Waves

Abstract Millimeter wave (MM-wave) electromagnetic fields (EMFs) are predicted to not produce penetrating effects in the body. The electric but not magnetic part of MM-EMFs are almost completely absorbed within the outer 1 mm of the body. Rodents are reported to have penetrating MM-wave impacts on the brain, the myocardium, liver, kidney and bone marrow. MM-waves produce electromagnetic sensitivity-like changes in rodent, frog and skate tissues. In humans, MM-waves have penetrating effects including impacts on the brain, producing EEG changes and other neurological/neuropsychiatric changes, increases in apparent electromagnetic hypersensitivity and produce changes on ulcers and cardiac activity. This review focuses on several issues required to understand penetrating effects of MM-waves and microwaves: 1. Electronically generated EMFs are coherent, producing much higher electrical and magnetic forces then do natural incoherent EMFs. 2. The fixed relationship between electrical and magnetic fields found in EMFs in a vacuum or highly permeable medium such as air, predicted by Maxwell’s equations, breaks down in other materials. Specifically, MM-wave electrical fields are almost completely absorbed in the outer 1 mm of the body due to the high dielectric constant of biological aqueous phases. However, the magnetic fields are very highly penetrating. 3. Time-varying magnetic fields have central roles in producing highly penetrating effects. The primary mechanism of EMF action is voltage-gated calcium channel (VGCC) activation with the EMFs acting via their forces on the voltage sensor, rather than by depolarization of the plasma membrane. Two distinct mechanisms, an indirect and a direct mechanism, are consistent with and predicted by the physics, to explain penetrating MM-wave VGCC activation via the voltage sensor. Time-varying coherent magnetic fields, as predicted by the Maxwell–Faraday version of Faraday’s law of induction, can put forces on ions dissolved in aqueous phases deep within the body, regenerating coherent electric fields which activate the VGCC voltage sensor. In addition, time-varying magnetic fields can directly put forces on the 20 charges in the VGCC voltage sensor. There are three very important findings here which are rarely recognized in the EMF scientific literature: coherence of electronically generated EMFs; the key role of time-varying magnetic fields in generating highly penetrating effects; the key role of both modulating and pure EMF pulses in greatly increasing very short term high level time-variation of magnetic and electric fields. It is probable that genuine safety guidelines must keep nanosecond timescale-variation of coherent electric and magnetic fields below some maximum level in order to produce genuine safety. These findings have important implications with regard to 5G radiation.

Brain stem – from general view to computational model based on switchboard rules of operation

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Włodzisław Duch ◽  
Dariusz Mikołajewski
Keyword(s):  
Brain Stem ◽  
Large Scale ◽  
Ionic Channels ◽  
General View ◽  
The Central Nervous System ◽  
Network States ◽  
Large Scale Simulations ◽  
Influence Of Noise ◽  
The Brain ◽  
Sufficient Precision

Abstract Despite great progress in understanding the functions and structures of the central nervous system (CNS) the brain stem remains one of the least understood systems. We know that the brain stem acts as a decision station preparing the organism to act in a specific way, but such functions are rather difficult to model with sufficient precision to replicate experimental data due to the scarcity of data and complexity of large-scale simulations of brain stem structures. The approach proposed in this article retains some ideas of previous models, and provides more precise computational realization that enables qualitative interpretation of the functions played by different network states. Simulations are aimed primarily at the investigation of general switching mechanisms which may be executed in brain stem neural networks, as far as studying how the aforementioned mechanisms depend on basic neural network features: basic ionic channels, accommodation, and the influence of noise.

scholarly journals Latent learning drives sleep-dependent plasticity in distinct CA1 subpopulations

2020 ◽  
Author(s):  
Wei Guo ◽  
Jie J. Zhang ◽  
Jonathan P. Newman ◽  
Matthew A. Wilson
Keyword(s):  
Hippocampal Neurons ◽  
Dimensional Manifold ◽  
Latent Learning ◽  
Neural Ensembles ◽  
Correlated Activity ◽  
Place Fields ◽  
Internal States ◽  
Low Dimensional ◽  
Low Dimensional Manifold ◽  
The Brain

AbstractLatent learning allows the brain the transform experiences into cognitive maps, a form of implicit memory, without reinforced training. Its mechanism is unclear. We tracked the internal states of the hippocampal neural ensembles and discovered that during latent learning of a spatial map, the state space evolved into a low-dimensional manifold that topologically resembled the physical environment. This process requires repeated experiences and sleep in-between. Further investigations revealed that a subset of hippocampal neurons, instead of rapidly forming place fields in a novel environment, remained weakly tuned but gradually developed correlated activity with other neurons. These ‘weakly spatial’ neurons bond activity of neurons with stronger spatial tuning, linking discrete place fields into a map that supports flexible navigation.

A Girl from Qatar with Post-Infantile Acquired Cerebral Palsy Caused By Submersion Injury: A Rare Etiology and a Therapeutic Challenge

2022 ◽  
Vol 5 (1) ◽  
pp. 01-04
Author(s):  
Aamir Jalal Al-Mosawi
Keyword(s):  
Cerebral Palsy ◽  
Evidence Based ◽  
Posterior Cortex ◽  
Her Family ◽  
Cortical Injury ◽  
Spontaneous Movements ◽  
Anoxic Encephalopathy ◽  
The Family ◽  
Deep Grey Matter ◽  
The Brain

Background: Cerebral palsy is a heterogeneous disorder that can cause a lifelong disability that is associated with a non-progressive damage in the brain. It is commonly caused by antenatal, perinatal, early postnatal and neonatal conditions. However, post-neonatal cases of acquired cerebral palsy have also been reported, and were commonly caused by infection. Patients and methods: The family of a girl from Qatar, who developed severe cerebral palsy caused by submersion injury, consulted us about the possible therapies for her condition. Clinical picture and brain imaging abnormalities are described, and the relevant literatures were reviewed with the aim of suggesting possible evidence-based therapies. Results: At the age of 23 months, a previously healthy girl developed anoxic encephalopathy after experiencing submersion injury. MRI showed evidence of significant hypoxic ischemic injury primarily affecting the deep grey matter, hippocami, mid-brain and the posterior cortex. EEG showed diffuse slowness of cerebral activity and diffuse attenuation of the background without no epileptic abnormalities suggesting diffuse encephalopathy resulting from diffuse cortical injury. At the about age of three and half years, her family consulted us about her condition as she was still showing no awareness to the environment, showing no significant spontaneous movements. She had poor head control. Unable to sit or stand alone, and had a flexed posture. She was on levetiracetam (Keppra), diazepam, and baclofen 30 mg daily. She was still having tracheotomy, and was fed through gastrostomy tube. Conclusion: In this paper, the rare occurrence of severe post-infantile cerebral palsy is described. Emphasis is made on the possibility of using evidence-based multi-factorial therapies in cerebral palsy.

Artifacts

2017 ◽  
pp. 98-127
Author(s):  
Riitta Hari ◽  
Aina Puce
Keyword(s):  
Data Analysis ◽  
Eye Movements ◽  
Cardiac Activity ◽  
Signal Space Separation ◽  
Eeg Data ◽  
Eeg Recordings ◽  
Power Line Noise ◽  
Post Hoc ◽  
Space Separation ◽  
The Brain

This chapter focuses on different types of biological and nonbiological artifacts in MEG and EEG recordings, and discusses methods for their recognition and removal. Examples are given of various physiological artifacts, including eye movements, eyeblinks, saccades, muscle, and cardiac activity. Nonbiological artifacts, such as power-line noise, are also demonstrated. Some examples are given to illustrate how these unwanted signals can be identified and removed from MEG and EEG signals with methods such as independent component analysis (as applied to EEG data) and temporal signal-space separation (applied to MEG data). However, prevention of artifacts is always preferable to removing or compensating for them post hoc during data analysis. The chapter concludes with a discussion of how to ensure that signals are emanating from the brain and not from other sources.

Exogenous L-lactate promotes astrocyte plasticity but is not sufficient for enhancing striatal synaptogenesis or motor behavior in mice

2020 ◽  
Author(s):  
Adam J. Lundquist ◽  
Tyler J. Gallagher ◽  
Giselle M. Petzinger ◽  
Michael W. Jakowec
Keyword(s):  
Motor Behavior ◽  
Early Gene ◽  
Specific Gene ◽  
Motor Circuits ◽  
Specific Manner ◽  
Primary Astrocytes ◽  
Exercise Induced ◽  
The Brain

AbstractL-lactate is an energetic and signaling molecule that is key to the metabolic and neuroplastic connection between astrocytes and neurons and may be involved in exercise-induced neuroplasticity. This study sought to explore the role of L-lactate in astrocyte reactivity and neuroplasticity. Using in vitro cultures of primary astrocytes, we show L-lactate increased expression of plasticity-related genes, including neurotrophic factors, Bdnf, Gdnf, Cntf and the immediate early gene cFos. L-lactate’s promotion of neurotrophic factor expression may be mediated in part by the lactate receptor HCAR1 since application of the HCAR1 agonist 3,5-DHBA also increased expression of Bdnf in primary astrocytes. In vivo L-lactate administration to healthy mice caused a similar increase in the expression of plasticity-related genes as well as increased astrocyte morphological complexity in a region-specific manner, with increased astrocytic response found in the striatum but not the ectorhinal cortex, regions of the brain where increases in regional cerebral blood flow are increased or unaltered, respectively, with motor behavior. Additionally, L-lactate administration did not cause synaptogenesis or improve motor behavior based on the latency to fall on the accelerating rotarod, suggesting that L-lactate administration can initiate astrocyte-specific gene expression, but the activation of motor circuits is necessary to initiate striatal neuroplasticity. These results suggest that peripheral L-lactate is likely an important molecular component of exercise-induced neuroplasticity by acting in an astrocyte-specific manner to prime the brain for neuroplasticity.

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