Cerebellar associative learning underlies skilled reach adaptation

Cerebellar output has been shown to enhance movement precision by scaling the decelerative phase of reaching movements in mice. We hypothesized that during reach, initial kinematics cue late-phase adjustments through cerebellar associative learning. We identify a population-level response in mouse PCs that scales inversely with reach velocity, suggesting a candidate mechanism for anticipatory control to target limb endpoint. We next interrogate how such a response is generated by combining high-density neural recordings with closed-loop optogenetic stimulation of cerebellar mossy fiber afferents originating in the pontine nuclei during reach, using perturbation schedules reminiscent of classic adaptation paradigms. We found that reach kinematics and PC electrophysiology adapt to position-locked mossy fiber perturbations and exhibit aftereffects when stimulation is removed. Surprisingly, we observed partial adaptation to position-randomized stimulation schedules but no opposing aftereffect. A model that recapitulated these findings provided novel insight into how the cerebellum deciphers cause-and-effect relationships to adapt.

Active inference through whiskers

Rodents use whisking to probe actively their environment and to locate objects in space, hence providing a paradigmatic biological example of active sensing. Numerous studies show that the control of whisking has anticipatory aspects. For example, rodents target their whisker protraction to the distance at which they expect objects, rather than just reacting fast to contacts with unexpected objects. Here we characterize the anticipatory control of whisking in rodents as an active inference process. In this perspective, the rodent is endowed with a prior belief that it will touch something at the end of the whisker protraction, and it continuously modulates its whisking amplitude to minimize (proprioceptive and somatosensory) prediction errors arising from an unexpected whisker-object contact, or from a lack of an expected contact. We will use the model to qualitatively reproduce key empirical findings about the ways rodents modulate their whisker amplitude during exploration and the scanning of (expected or unexpected) objects. Furthermore, we will discuss how the components of active inference model can in principle map to the neurobiological circuits of rodent whisking.

ALGORITHMS OF THE CONTROL PROGRAM OF AUTOMATIC CLEANING SYSTEMS OF THE TURNOUTS BASED ON THE SENSOR FOR DETERMINING ICE OR SNOW ON THE CONTROLLED SURFACE

The structure of an automatic system for cleaning turnouts is considered, the main advantages and disadvantages of precipitation sensors of existing automatic systems for cleaning turnouts are analyzed. It is concluded that it is necessary to develop an advanced system based on a sensor for de- tecting ice or snow on a controlled surface. The developed block diagram of the formation of control actions of the system for detecting icing or snow on the controlled surface is presented. An algorithm is given for its technical implementation, as well as for measuring the anticipatory control of the process of electric heating of the controlled surface of the switches. The results of simulation of the device and method for determining ice or snow on a controlled surface in the Matlab Simulink environment are presented.

An Electromyographic Analysis of the Effects of Cognitive Fatigue on Online and Anticipatory Action Control

Cognitive fatigue is a problem for the safety of critical systems (e.g., aircraft) as it can lead to accidents, especially during unexpected events. In order to determine the extent to which it disrupts adaptive capabilities, we evaluated its effect on online and anticipatory control. Despite numerous studies conducted to determine its effects, the exact mechanism(s) affected by fatigue remains to be clarified. In this study, we used distribution and electromyographic analysis to assess whether cognitive fatigue increases the capture of the incorrect automatic response or if it impairs its suppression (online control), and whether the conflict adaptation effect is reduced (anticipatory control). To this end, we evaluated the evolution of the performance over time during the Simon task, a classic conflict task that elicits incorrect automatic responses. To accentuate the presence of fatigue during the Simon task, two groups previously performed a dual-task with two different cognitive load levels to create two different levels of fatigue. The results revealed that time on task impaired online control by disrupting the capacity to suppress the incorrect response but leaving unaffected the expression of the automatic response. Furthermore, participants emphasized speed rather than accuracy with time on task, with in addition more fast guesses, suggesting that they opted for a less effortful response strategy. As the implementation of the suppression mechanism requires cognitive effort, the conjunction of these results suggests that the deficits observed may be due to disengagement of effort over time rather than reflecting an incapacity to make an effort.

Independent walking and balance in children with CHARGE syndrome

Children with CHARGE syndrome (CWCS) are born with multiple physical disabilities, several of which impair balance and the onset of motor milestones. Early motor development problems can include delayed independent walking, which has been found in CWCS. In addition, few studies have examined balance in CWCS and these studies have been limited in scope, necessitating a more comprehensive examination of balance in this population. Motor development occurs as a progression of stages as represented by Seefeldt’s conceptual model. As such, it is essential to examine the association of early development of foundational skills, such as balance, with the onset of motor milestones as they are building blocks to motor competence. The aims of this study are to (1) examine the differential effects of children with and without CHARGE syndrome on balance and (2) examine the association of age of walking to these balance measures. In this study, 27 CWCS and 22 children without CHARGE syndrome, aged 7 to 16 years, were assessed on four components of balance including anticipatory control, reactive postural control, sensory orientation, and dynamic gait using the shortened version of the Balance Evaluation Systems Test (mini-BESTest) and parental reported age of independent walking. Their balance and age of walking were compared to 22 typically developing peers of similar age and gender distribution. Results revealed that CWCS walked three times later than their peers without CHARGE syndrome and had significant deficits on all balance systems assessed with the largest difference occurring in anticipatory control. Anticipatory control is critically important in maintaining static and dynamic postural control. These results indicate a critical need for early functional balance training and compensatory strategies in CWCS.

Relationship Between Motor Skills, Balance, and Physical Activity in Children with CHARGE Syndrome

Introduction: Children with CHARGE syndrome often show delays in balance and motor skills due to multisensory impairments. Research also suggests that children with CHARGE syndrome have fewer opportunities to engage in physical activity. However, little research has examined the relationship among all of these variables. Thus, the purpose of this study was to examine the relationship between balance, motor skills, and physical activity. Methods: Participants consisted of 37 children with CHARGE syndrome aged 3–16 years who could walk independently. Parents of each child with CHARGE syndrome completed a demographics questionnaire and the Physical Activity Questionnaire for Children or Adolescents. Their child completed the Mini-BEST balance test and five motor skills (run, jump, slide, kick, and throw) from the Test of Gross Motor Development II. Results: Results indicate that anticipatory control had significant positive correlations with all five motor skills, sensory orientation with three motor skills, and reactive postural control and dynamic gait with two motor skills. Running was the only variable that had a significant positive correlation with physical activity. Discussion: The findings indicate that balance, especially anticipatory control, plays an important role in fundamental motor skills of children with CHARGE syndrome. There is also a strong connection between physical activity and running competence for this population; however, since this is based on a correlational analysis, the direction of the relationship is unclear. Implications for practitioners: Physical education teachers should work with students with CHARGE syndrome on increasing balance and motor skill performance to give them the competence and confidence to engage in physical activity. Moreover, parents can help by engaging in physical activity with their child at an early age and seeking out additional physical activity opportunities for their child outside of the physical education and school setting.