Sensorimotor Skill Learning Research Articles

Mechanical Problem Solving in Goffin's Cockatoos-Towards Modeling Complex Behavior.

Goffin's cockatoos (Cacatua goffiniana) can solve a diverse set of mechanical problems, such as tool use, tool manufacture, and mechanical puzzles. However, the proximate mechanisms underlying this adaptive behavior are largely unknown. Similarly, engineering artificial agents that can as flexibly solve such mechanical puzzles is still a substantial challenge in areas such as robotics. This article is an interdisciplinary approach to study mechanical problem solving which we hope is relevant to both fields. The behavior we are studying results from the interaction between a complex environment (the lockbox) and different processes that govern the animals' behavior. We therefore jointly analyze the parrots' (1) engagement, (2) sensorimotor skill learning, and (3) action selection. We find that none of these aspects could solely explain the animals' behavioral adaptation and that a plausible model of proximate mechanisms must jointly address these aspects. We accompany this analysis with a discussion of methods to identify such mechanisms. At the same time, we argue, it is implausible to identify a detailed model from the limited behavioral data of just a few studies. Instead, we advocate for an incremental approach to model building in which one first establishes constraints on proximate mechanisms before specific, detailed models are formulated. To illustrate this idea, we apply it to the data presented here. We argue that as the field attempts to find mechanistic explanations for increasingly complex behaviors, such alternative modeling approaches will be necessary.

Microstructural Properties of the Cerebellar Peduncles in Children With Developmental Language Disorder.

Children with developmental language disorder (DLD) struggle to learn their native language for no apparent reason. While research on the neurobiological underpinnings of the disorder has focused on the role of corticostriatal systems, little is known about the role of the cerebellum in DLD. Corticocerebellar circuits might be involved in the disorder as they contribute to complex sensorimotor skill learning, including the acquisition of spoken language. Here, we used diffusion-weighted imaging data from 77 typically developing and 54 children with DLD and performed probabilistic tractography to identify the cerebellum's white matter tracts: the inferior, middle, and superior cerebellar peduncles. Children with DLD showed lower fractional anisotropy (FA) in the inferior cerebellar peduncles (ICP), fiber tracts that carry motor and sensory input via the inferior olive to the cerebellum. Lower FA in DLD was driven by lower axial diffusivity. Probing this further with more sophisticated modeling of diffusion data, we found higher orientation dispersion but no difference in neurite density in the ICP of children with DLD. Reduced FA is therefore unlikely to be reflecting microstructural differences in myelination, rather the organization of axons in these pathways is disrupted. ICP microstructure was not associated with language or motor coordination performance in our sample. We also found no differences in the middle and superior peduncles, the main pathways connecting the cerebellum with the cortex. To conclude, it is not corticocerebellar but atypical olivocerebellar white matter connections that characterize DLD and suggest the involvement of the olivocerebellar system in speech and language acquisition and development.

Playing with your ears: Audio-motor skill learning is sensitive to the lateral relationship between trained hand and ear

A salient feature of motor and sensory circuits in the brain is their contralateral hemispheric bias-a feature that might play a role in integration and learning of sensorimotor skills. In the current behavioral study, we examined whether the lateral configuration between sound-producing hand and feedback-receiving ear affects performance and learning of an audio-motor skill. Right-handed participants (n=117) trained to play a piano sequence using their right or left hand while auditory feedback was presented monaurally, either to the right or left ear. Participants receiving auditory feedback to the contralateral ear during training performed better than participants receiving ipsilateral feedback (with respect to the training hand). Furthermore, in the Left-Hand training groups, the contralateral training advantage persisted in a generalization task. Our results demonstrate that audio-motor learning is sensitive to the lateral configuration between motor and sensory circuits and suggest that integration of neural activity across hemispheres facilitates such learning.

Whole-body sensorimotor skill learning in football players: No evidence for motor transfer effects.

Besides simple movement sequences, precise whole-body motor sequences are fundamental for top athletic performance. It has long been questioned whether athletes have an advantage when learning new whole-body motor sequences. In a previous study, we did not find any superior learning or transfer effects of strength and endurance athletes in a complex whole-body serial reaction time task (CWB-SRTT). In the present study, we aimed to extend this research by increasing the overlap of task requirements between CWB-SRTT and a specific sports discipline. For this purpose, we assessed differences between football players and non-athletes during motor sequence learning using CWB-SRTT. 15 non-athletes (CG) and 16 football players (FG) performed the CWB-SRTT over 2 days separated by one week. Median reaction times and movement times were analyzed as well as differences in sequence-specific CWB-SRTT learning rates and retention. Our findings did not reveal any differences in sequence-specific or non-sequence-specific improvement, nor retention rates between CG and FG. We speculate that this might relate to a predominately cognitive-induced learning effect during CWB-SRTT which negates the assumed motor advantage of the football players.

Comparison of whole-body sensorimotor skill learning between strength athletes, endurance athletes and healthy sedentary adults

Motor sequences represent an integral part of human motor ability. Apart from simple movement sequences, complex coordinated movement sequences are the building blocks for peak athletic performance. Accordingly, optimized temporal and spatial coordination of muscle action across multiple limbs may be a distinguishing feature between athletes and non-athletes in many sports. In the present study, we aimed to assess differences between strength and endurance athletes and non-athletes during learning of a complex whole-body serial reaction time task (CWB-SRTT). For this purpose, 26 nonathletes (NAG) and 25 athletes (AG) learned the CWB-SRTT over 2 days separated by 7 days. Mean response times of participants were recorded and statistically analyzed for sequence-specific and non-sequence-specific improvements, as well as differences in learning rates and retention. Furthermore, AG was subdivided into strength (SG) and endurance (EG) athletes, and all analysis steps were repeated. Our results show a better mean response time of AG compared to NAG. However, we could not detect differences in sequence-specific or non-sequence-specific learning, as well as different retention rates between NAG and AG or SG and EG. We assume here that a potential lack of motor transfer between general athletic abilities and the specific complex motor sequence mainly accounts for our findings.

Structural connectivity prior to whole-body sensorimotor skill learning associates with changes in resting state functional connectivity

Changes in resting state functional connectivity are induced by sensorimotor training and assumed to be concomitant of motor learning, although a potential relationship between functional and structural connectivity associated with sensorimotor sequence learning remains elusive. To investigate whether initial structural connectivity relates to changes in functional connectivity, we evaluated resting state functional connectivity (rs-FC), white matter fibre density (FD), fibre-bundle cross-section (FC), and gray matter volume (GMV) in healthy human participants before and after two days of performing a complex whole-body serial reaction time task (CWB-SRTT). As CWB-SRTT was implicit, participants were not told about the presence of any sequence. Since the lateral prefrontal cortex (PFC) plays an important role in sequence learning, we hypothesized that structural connectivity within the PFC prior to learning is associated with changes in rs-FC involving the lateral PFC. Sequence specific improvements, as assessed by the time difference between the last random and the last sequence blocks, were observed for reaction times, suggesting that sensorimotor sequence memory was acquired. Rs-FC between the right lateral PFC and bilateral striatum increased significantly in the learning group, when compared to a control group who performed only random blocks. This indicated that rs-FC changes are related to sequence memory but not to exercise itself. In addition, changes in rs-FC between the right lateral PFC and the left striatum were correlated with sequence specific improvements in individual reaction times. Furthermore, changes in rs-FC between right lateral PFC and left striatum were positively correlated with FC in the right anterior corona radiata measured before the task. We did not find any structural changes or significant correlations in FD or GMV. These findings suggest that an early phase of sensorimotor sequence learning in complex whole-body movements is associated with an increase in rs-FC between prefrontal and subcortical regions. Furthermore, we provide novel evidence that CWB-SRTT-induced changes in rs-FC were correlated with FC within the PFC.

Postural control does not affect performing or learning a temporal estimation task in physically active older adults

Evidence suggests that postural control could act as a secondary task, leading to a negative effect on sensorimotor skill learning. To investigate this issue, twenty older adults (average age = 70.5 years, SD=5.6) were distributed into two groups, according to the body position maintained during the acquisition (AQ) of a temporal estimation task: performing the task standing with feet together (STA) or sitting (SIT). During the AQ, participants performed 90 trials of the task consisting of synchronising the arrival of two rectangles (‘Target A’ and ‘Target B’) to a target line. The velocity of Target A was chosen by the participants, among three possible ones, before each trial, without exceeding 30 trials per velocity. Target B had only one velocity and should be released by the participants, with a button press, when they judged it would reach the target line simultaneously with Target A. Contrary to what has been shown in studies with reaction time, postural control did not affect the performance of our temporal estimation task. Additionally, no effects on sensorimotor learning – inferred by immediate and delayed transfer tests – were found. Result suggests that postural control may not interfere with cognitive resources used to perform a simultaneous task, when this task does not demand fast processing, i.e. is not highly time constrained. Future studies should consider the physical activity level of participants, since the fact that all participants in the present study were physically active may have contributed to the observed results.

Neuroplasticity subserving the operation of brain–machine interfaces

Neuroplasticity is key to the operation of brain machine interfaces (BMIs)—a direct communication pathway between the brain and a man-made computing device. Whereas exogenous BMIs that associate volitional control of brain activity with neurofeedback have been shown to induce long lasting plasticity, endogenous BMIs that use prolonged activity-dependent stimulation – and thus may curtail the time scale that governs natural sensorimotor integration loops – have been shown to induce short lasting plasticity. Here we summarize recent findings from studies using both categories of BMIs, and discuss the fundamental principles that may underlie their operation and the longevity of the plasticity they induce. We draw comparison to plasticity mechanisms known to mediate natural sensorimotor skill learning and discuss principles of homeostatic regulation that may constrain endogenous BMI effects in the adult mammalian brain. We propose that BMIs could be designed to facilitate structural and functional plasticity for the purpose of re-organization of target brain regions and directed augmentation of sensorimotor maps, and suggest possible avenues for future work to maximize their efficacy and viability in clinical applications.

Making fingers and words count in a cognitive robot

Evidence from developmental as well as neuroscientific studies suggest that finger counting activity plays an important role in the acquisition of numerical skills in children. It has been claimed that this skill helps in building motor-based representations of number that continue to influence number processing well into adulthood, facilitating the emergence of number concepts from sensorimotor experience through a bottom-up process. The act of counting also involves the acquisition and use of a verbal number system of which number words are the basic building blocks. Using a Cognitive Developmental Robotics paradigm we present results of a modeling experiment on whether finger counting and the association of number words (or tags) to fingers, could serve to bootstrap the representation of number in a cognitive robot, enabling it to perform basic numerical operations such as addition. The cognitive architecture of the robot is based on artificial neural networks, which enable the robot to learn both sensorimotor skills (finger counting) and linguistic skills (using number words). The results obtained in our experiments show that learning the number words in sequence along with finger configurations helps the fast building of the initial representation of number in the robot. Number knowledge, is instead, not as efficiently developed when number words are learned out of sequence without finger counting. Furthermore, the internal representations of the finger configurations themselves, developed by the robot as a result of the experiments, sustain the execution of basic arithmetic operations, something consistent with evidence coming from developmental research with children. The model and experiments demonstrate the importance of sensorimotor skill learning in robots for the acquisition of abstract knowledge such as numbers.

Viewpoint: What Brain Research Can Tell Us About Accent Modification

The field of brain research has made numerous advances in the past few decades into how we learn new motor skills, from the value of sleep to the discovery of “mirror neurons,” which fire when we watch others performing movements we are attempting to learn. Accent modification may be conceptualized as a form of sensorimotor skill learning – learning to produce a set of movement components and performing them as a whole automatically in spontaneous speech. Motor skill learning occurs in stages and motor habits are formed after acquisition of the new behavior, consolidation of the new brain patterns, and automatic production in appropriate settings. New neural pathways are formed and both cortical and subcortical brain regions participate. The author of this article reviews concepts from the neuroscience literature in the field of motor skill acquisition, work which has primarily focused on the learning of arm and finger movements, and attempts to apply them in a practical manner for the clinician working with non-native English speakers. Discussed are the neurophysiology of motor skill learning, stages of habit formation, intermittent practice, sleep, feedback, mirror neurons and motor imagery. Practical suggestions are given to optimize the accent modification process for the clinician and client.

Atypically diffuse functional connectivity between caudate nuclei and cerebral cortex in autism

BackgroundAutism is a neurodevelopmental disorder affecting sociocommunicative behavior, but also sensorimotor skill learning, oculomotor control, and executive functioning. Some of these impairments may be related to abnormalities of the caudate nuclei, which have been reported for autism.MethodsOur sample was comprised of 8 high-functioning males with autism and 8 handedness, sex, and age-matched controls. Subjects underwent functional MRI scanning during performance on simple visuomotor coordination tasks. Functional connectivity MRI (fcMRI) effects were identified as interregional blood oxygenation level dependent (BOLD) signal cross-correlation, using the caudate nuclei as seed volumes.ResultsIn the control group, fcMRI effects were found in circuits with known participation of the caudate nuclei (associative, orbitofrontal, oculomotor, motor circuits). Although in the autism group fcMRI effects within these circuits were less pronounced or absent, autistic subjects showed diffusely increased connectivity mostly in pericentral regions, but also in brain areas outside expected anatomical circuits (such as visual cortex).ConclusionThese atypical connectivity patterns may be linked to developmental brain growth disturbances recently reported in autism and suggest inefficiently organized functional connectivity between caudate nuclei and cerebral cortex, potentially accounting for stereotypic behaviors and executive impairments.

Sensorimotor skill learning in amnesia: additional evidence for the neural basis of nondeclarative memory.

We investigated sensorimotor skill learning, a form of nondeclarative (implicit) memory, in 28 subjects with declarative (explicit) memory defects caused by either mesial temporal (n = 15) or basal forebrain (n = 13) damage and in 66 normal control subjects. All 28 amnesics had normal learning of a rotor pursuit task. We also studied in detail the sensorimotor skill learning of patient Boswell. As a result of bilateral damage to both mesial and lateral aspects of the temporal lobes and to the basal forebrain, Boswell has one of the most severe impairments ever reported for learning of all types of declarative knowledge. Compared to matched controls, Boswell acquired and retained normally the skills associated with performing motor tasks. We conducted a long-term (2-year) followup study of Boswell's retention of the rotor pursuit task, and we found that he retained the skill as well as normal controls. Our study builds on previous work in the following respects: (1) It provides evidence, for the first time, that skill learning is normal in basal forebrain amnesics; (2) it shows that patient Boswell has normal learning and long-term retention of sensorimotor skills, in spite of his extensive damage; and (3) it offers additional evidence that mesial temporal lobe damage spares skill learning. These findings demonstrate unequivocally that sensorimotor skill learning does not require structures in mesial and lateral temporal regions nor in basal forebrain.