Motor Planning Research Articles

Dynamics of Saccade Trajectory Modulation by Distractors: Neural Activity Patterns in the Frontal Eye Field.

The sudden appearance of a visual distractor shortly before saccade initiation can capture spatial attention and modulate the saccade trajectory in spite of the ongoing execution of the initial plan to shift gaze straight to the saccade target. To elucidate the neural correlates underlying these curved saccades, we recorded from single neurons in the frontal eye field (FEF) of two male rhesus monkeys shifting gaze to a target while a distractor with the same eccentricity appeared either left or right of the target at various delays after target presentation. We found that the population level of pre-saccadic activity of neurons representing the distractor location encoded the direction of the saccade trajectory. Stronger activity occurred when saccades curved toward the distractor, and weaker when saccades curved away. This relationship held whether the distractor was ipsilateral or contralateral to the recorded neurons. Meanwhile, visually responsive neurons showed asymmetrical patterns of excitatory responses that varied with the location of the distractor and the duration of distractor processing relating to attentional capture and distractor inhibition. During earlier distractor processing, neurons encoded curvature towards the distractor. During later distractor processing, neurons encoded curvature away from the distractor. This was observed when saccades curved away from distractors contralateral to the recording site and when saccades curved towards distractors ipsilateral to the recording site. These findings indicate that saccadic motor planning involves dynamic push-pull hemispheric interactions producing attraction or repulsion for potential but unselected saccade targets.Significant Statement This study not only advances our understanding of oculomotor function in dynamic environments but also has potential clinical relevance for diagnosing and understanding disorders characterized by abnormal saccade trajectories. Our research elucidates the neural mechanisms behind saccade trajectories that are not always linear due to the brain's integration of multiple visual cues and/or motor plans. By analyzing the frontal eye field (FEF) activity in rhesus monkeys, we found that saccade directionality and timing are influenced by the interaction between FEF visual neurons representing target and distractor stimuli. The FEF's role extends beyond a winner-takes-all approach, incorporating saccade vector averaging computations that produce curved saccades. Furthermore, ipsilateral visual neurons encode distractor suppression that drives curvature away from the distractor.

Alcohol exposure induces cortical activity change during quiescent state

Alcohol Use Disorder (AUD) is a significant global mental health issue that impacts both the central and peripheral systems, leading to widespread cognitive and motor dysfunctions. The primary motor cortex (M1) plays a critical role in motor planning, control, and execution, yet the effects of chronic alcohol exposure on M1 remain underexplored, particularly during quiescent states. This study investigates the functional changes in M1 due to chronic alcohol exposure using high-resolution Neuropixels electrode recordings in a mouse model. Our findings reveal alterations in neuronal firing mode, particularly in layer V, highlighting disruptions in the excitatory/inhibitory (E/I) balance. Despite similar overall firing rates, changes in firing interval distributions suggest altered temporal dynamics of neuronal activity due to alcohol exposure. These results align with existing literature on cortical disruptions caused by alcohol and provide new insights into the specific neuronal dynamics within M1, especially in quiescent states.

Difficulties in perceptual–motor coordination of reaching behavior in children with autism spectrum disorder

Increased risk of injury from collisions with objects is an important issue in children with autism spectrum disorder (ASD). The purpose of the present study was to examine whether impaired perceptual–motor coordination may underlie the high frequency of collisions. Specifically, we hypothesized that collisions are likely to occur frequently in children with ASD due to their difficulty with body-related spatial perception and their inadequate motor planning, due to their detail-focused processing style, i.e., a tendency to focus attention on specific details rather than on the overall context. To evaluate impairment of perceptual–motor coordination in children with ASD, an original action selection task was developed to assess (a) body-related spatial perception and (b) predictive attentional properties for planning the subsequent movements based on the measures of hand movement and gaze behavior. Twenty-six children (13 diagnosed as ASD and 13 with typical development [TD]) completed the task, and their parents completed a questionnaire regarding their child's susceptibility to injury. Results showed that children with ASD displayed inaccurate body-related spatial perception and inadequate motor planning under conditions that induced their detail-focused processing style. In addition, analyses of gaze behavior reflected the characteristics of a detail-focused processing in children with ASD. This was correlated with the severity of ASD and the measure of motor planning. The present findings suggest that difficulty with perceptual–motor coordination, resulting in part from the detail-focused processing style, might contribute to susceptibility to injury in children with ASD. We consider that our evaluation of the difficulty with perceptual–motor of individuals with ASD provides a framework for understanding their high rate of collision-related injuries and could inform strategies for preventing these injuries.

Subthalamic nucleus neurons encode syllable sequence and phonetic characteristics during speech.

Speech is a complex behavior that can be used to study unique contributions of the basal ganglia to motor control in the human brain. Computational models suggest that the basal ganglia encode either the phonetic content or the sequence of speech elements. To explore this question, we investigated the relationship between phoneme and sequence features of a spoken syllable triplet and the firing rate of subthalamic nucleus (STN) neurons recorded during the implantation of deep brain stimulation (DBS) electrodes in individuals with Parkinson's disease. Patients repeated aloud a random sequence of three consonant-vowel (CV) syllables in response to audio cues. Single-unit extracellular potentials were sampled from the sensorimotor STN; a total of 227 unit recordings were obtained from the left STN of 25 subjects (4 females). Of these, 113 (50%) units showed significant task-related increased firing and 53 (23%) showed decreased firing (t test relative to inter-trial period baseline, P < 0.05). Linear regression analysis revealed that both populations of STN neurons encode phoneme and sequence features of produced speech. Maximal phoneme encoding occurred at the time of phoneme production, suggesting efference copy- or sensory-related processing, rather than speech motor planning (-50 ms and +175 ms relative to CV transition for consonant and vowel encoding, respectively). These findings demonstrate that involvement of the basal ganglia in speaking includes separate single unit representations of speech sequencing and phoneme selection in the STN.NEW & NOTEWORTHY Speech is a unique human behavior that requires dynamic execution of precisely timed and coordinated movements, resulting in intelligible vocalizations. Here, we demonstrate that activity of individual neurons in the subthalamic nucleus (STN) of the basal ganglia encode syllable sequence order and phoneme identity during a speech production task. These findings advance our understanding of neural substrates of human speech and shed light on potential involvement of the STN in complex human behaviors.

A geometrical solution underlies general neural principle for serial ordering

A general mathematical description of how the brain sequentially encodes knowledge remains elusive. We propose a linear solution for serial learning tasks, based on the concept of mixed selectivity in high-dimensional neural state spaces. In our framework, neural representations of items in a sequence are projected along a “geometric” mental line learned through classical conditioning. The model successfully solves serial position tasks and explains behaviors observed in humans and animals during transitive inference tasks amidst noisy sensory input and stochastic neural activity. This approach extends to recurrent neural networks performing motor decision tasks, where the same geometric mental line correlates with motor plans and modulates network activity according to the symbolic distance between items. Serial ordering is thus predicted to emerge as a monotonic mapping between sensory input and behavioral output, highlighting a possible pivotal role for motor-related associative cortices in transitive inference tasks.

Effectiveness of an object moving depending on its orientation in the environment: a kinematic analysis of motor planning and execution

Background. Grasping objects with the hand is one of the most common movements in everyday life. It requires training involving the cognitive processes of goal selection and motor planning.Aim. To investigate the effect of object rotation on motor planning using an experiment where participants moved abstract objects that sometimes required rotation, and movement was assessed using a kinematic analysis system. We hypothesized that reaction times and movements would be longer for tasks with rotation.Materials and methods. Sixteen subjects participated in the study (11 females and 5 males), mean age – 23.375 ± 2.277 years. Participants were required to perform a task of moving 4 abstract objects onto corresponding platforms with their right hand, while periodically rotating the object by 90°, 180°, or 270°. The motion tracking system monitored the movement of trackers located on the subject’s right thumb and index finger, on the subject’s right wrist, and on the object and the subject’s special glasses.Results. To assess the effect of object rotation on motor planning, the data were grouped according to the angle of rotation. A one-factor analysis of variance with repeated measures was used. The results showed statistically significant differences:total movement time as a function of turning angle: F(3.45) = 5.014, p = 0.004;time to reach the grasping target: F(3.45) = 61.79, p = 0.001;object motion time: F(3.45) = 14.641, p = 0.001;time to reach maximum capture aperture: F(3.45) = 8.559, p = 0.001.Conclusion. Overall, our results support the hypothesis that object rotation during movement affects both the preparation and execution of the movement itself. The planning and executing the movement with the object rotated 180° was easier and faster than with 90° and 270° rotations. The testing allows distinguishing the stages of planning and preparation of the movement from the execution of the movement itself. Using this approach in patients with central nervous system lesions helps to assess and monitor the state of motor function, which is important for monitoring the recovery process.

Brain-wide dynamics linking sensation to action during decision-making.

Perceptual decisions rely on learned associations between sensory evidence and appropriate actions, involving the filtering and integration of relevant inputs to prepare and execute timely responses1,2. Despite the distributed nature of task-relevant representations3-10, it remains unclear how transformations between sensory input, evidence integration, motor planning and execution are orchestrated across brain areas and dimensions of neural activity. Here we addressed this question by recording brain-wide neural activity in mice learning to report changes in ambiguous visual input. After learning, evidence integration emerged across most brain areas in sparse neural populations that drive movement-preparatory activity. Visual responses evolved from transient activations in sensory areas to sustained representations in frontal-motor cortex, thalamus, basal ganglia, midbrain and cerebellum, enabling parallel evidence accumulation. In areas that accumulate evidence, shared population activity patterns encode visual evidence and movement preparation, distinct from movement-execution dynamics. Activity in movement-preparatory subspace is driven by neurons integrating evidence, which collapses at movement onset, allowing the integration process to reset. Across premotor regions, evidence-integration timescales were independent of intrinsic regional dynamics, and thus depended on task experience. In summary, learning aligns evidence accumulation to action preparation in activity dynamics across dozens of brain regions. This leads to highly distributed and parallelized sensorimotor transformations during decision-making. Our work unifies concepts from decision-making and motor control fields into a brain-wide framework for understanding how sensory evidence controls actions.

Neural correlates of bradykinesia in Parkinson’s disease: a kinematic and functional MRI study

Bradykinesia is defined as a “complex” of motor alterations including decreased movement amplitude and/or speed and tendency to reduce them with movement repetition (sequence effect). This study aimed at investigating the neural and kinematic correlates of bradykinesia during hand-tapping in people with Parkinson’s disease (pwPD) relative to healthy controls. Twenty-five pwPD and 25 age- and sex-matched healthy controls underwent brain functional MRI (fMRI) during a hand-tapping task: subjects alternatively opened and closed their right hand as fully and quickly as possible. Hand-tapping kinematic parameters were objectively measured during the fMRI task using an optical fibre glove. During the fMRI task, pwPD showed reduced hand-tapping amplitude (hypokinesia) and a greater sequence effect. PwPD relative to healthy controls showed a reduced activity of fronto-parietal areas, middle cingulum/supplementary motor area (SMA), parahippocampus, pallidum/thalamus and motor cerebellar areas. Moreover, pwPD showed an increased activity of brain cognitive areas such as superior temporal gyrus, posterior cingulum, and cerebellum crus I. The decreased activity of cerebellum IV–V–VI, vermis IV–V, inferior frontal gyrus, and cingulum/SMA correlated with hypokinesia and with the sequence effect. Interestingly, a reduced activity of areas involved in motor planning and timing correlated both with hypokinesia and with the sequence effect in pwPD. This study has the major strength of collecting objective motor parameters and brain activity simultaneously, providing a unique opportunity to investigate the neural correlates of the “bradykinesia complex”.

Considerations for identifying subtypes of speech sound disorder.

Speech sound disorders (SSDs) in children are heterogeneous. Differentiating children with SSDs into distinct subtypes is important so that each child receives a treatment approach well suited to the particular difficulties they are experiencing. To study the distinct underlying processes that differentiate phonological processing, phonological planning or motor planning deficits. The literature on the nature of SSDs is reviewed to reveal diagnostic signs at the level of distal causes, proximal factors and surface characteristics. Subtypes of SSDs may be identified by linking the surface characteristics of the children's speech to underlying explanatory proximal factors. The proximal factors may be revealed by measures of speech perception skills, phonological memory and speech-motor control. The evidence suggests that consistent phonological disorder (CPD) can be identified by predictable patterns of speech error associated with speech perception errors. Inconsistent phonological disorder (IPD) is associated with a deficit in the selection and sequencing of phonemes, that is, revealed as within-word inconsistency and poor phonological memory. The motor planning deficit that is specific to childhood apraxia of speech (CAS) is revealed by transcoding errors on the syllable repetition task and an inability to produce [pətəkə] accurately and rapidly. Children with SSDs form a heterogeneous population. Surface characteristics overlap considerably among those with severe disorders, but certain signs are unique to particular subtypes. Careful attention to underlying causal factors will support the accurate diagnosis and selection of personalized treatment options. What is already known on the subject SSD in children are heterogenous, with numerous subtypes of primary SSD proposed. Diagnosing the specific subtype of SSD is important in order to assign the most efficacious treatment approach for each child. Identifying the distinct subtype for each child is difficult because the surface characteristics of certain subtypes overlap among categories (e.g., CPD or IPD; CAS). What this paper adds to the existing knowledge The diagnostic challenge might be eased by systematic attention to explanatory factors in relation to the surface characteristics, using specific tests for this purpose. Word identification tasks tap speech perception skills; repetition of short versus long strings of nonsense syllables permits observation of phonological memory and phonological planning skills; and standard maximum performance tests provide considerable information about speech motor control. What are the potential or actual clinical implications of this work? Children with SSDs should receive comprehensive assessments of their phonological processing, phonological planning and motor planning skills frequently, alongside examinations of their error patterns in connected speech. Such assessments will serve to identify the child's primary challenges currently and as they change over developmental time.

Visuomotor prediction during action planning in the human frontoparietal cortex and cerebellum.

The concept of forward models in the brain, classically applied to describing on-line motor control, can in principle be extended to action planning, i.e. assuming forward sensory predictions are issued during the mere preparation of movements. To test this idea, we combined a delayed movement task with a virtual reality based manipulation of visuomotor congruence during functional magnetic resonance imaging. Participants executed simple hand movements after a delay. During the delay, two aspects of the upcoming movement could be cued: the movement type and the visuomotor mapping (i.e. congruence of executed hand movements and visual movement feedback by a glove-controlled virtual hand). Frontoparietal areas showed increased delay period activity when preparing pre-specified movements (cued > uncued). The cerebellum showed increased activity during the preparation for incongruent > congruent visuomotor mappings. The left anterior intraparietal sulcus showed an interaction effect, responding most strongly when a pre-specified (cued) movement was prepared under expected visuomotor incongruence. These results suggest that motor planning entails a forward prediction of visual body movement feedback, which can be adjusted in anticipation of nonstandard visuomotor mappings, and which is likely computed by the cerebellum and integrated with state estimates for (planned) control in the anterior intraparietal sulcus.

Future movement plans interact in sequential arm movements.

Real-world actions often comprise a series of movements that cannot be entirely planned before initiation. When these actions are executed rapidly, the planning of multiple future movements needs to occur simultaneously with the ongoing action. How the brain solves this task remains unknown. Here, we address this question with a new sequential arm reaching paradigm that manipulates how many future reaches are available for planning while controlling execution of the ongoing reach. We show that participants plan at least two future reaches simultaneously with an ongoing reach. Further, the planning processes of the two future reaches are not independent of one another. Evidence that the planning processes interact is twofold. First, correcting for a visual perturbation of the ongoing reach target is slower when more future reaches are planned. Second, the curvature of the current reach is modified based on the next reach only when their planning processes temporally overlap. These interactions between future planning processes may enable smooth production of sequential actions by linking individual segments of a long sequence at the level of motor planning.

Future movement plans interact in sequential arm movements

Real-world actions often comprise a series of movements that cannot be entirely planned before initiation. When these actions are executed rapidly, the planning of multiple future movements needs to occur simultaneously with the ongoing action. How the brain solves this task remains unknown. Here, we address this question with a new sequential arm reaching paradigm that manipulates how many future reaches are available for planning while controlling execution of the ongoing reach. We show that participants plan at least two future reaches simultaneously with an ongoing reach. Further, the planning processes of the two future reaches are not independent of one another. Evidence that the planning processes interact is twofold. First, correcting for a visual perturbation of the ongoing reach target is slower when more future reaches are planned. Second, the curvature of the current reach is modified based on the next reach only when their planning processes temporally overlap. These interactions between future planning processes may enable smooth production of sequential actions by linking individual segments of a long sequence at the level of motor planning.

Motor practice related changes in the sensorimotor cortices of youth with cerebral palsy.

The altered sensorimotor cortical dynamics seen in youth with cerebral palsy appear to be tightly coupled with their motor performance errors and uncharacteristic mobility. Very few investigations have used these cortical dynamics as potential biomarkers to predict the extent of the motor performance changes that might be seen after physical therapy or in the design of new therapeutic interventions that target a youth's specific neurophysiological deficits. This cohort investigation was directed at evaluating the practice dependent changes in the sensorimotor cortical oscillations exhibited by youth with cerebral palsy as a step towards addressing this gap. We used magnetoencephalography to image the changes in the cortical oscillations before and after youth with cerebral palsy (N = 25; age = 15.2 ± 4.5 years; Gross Motor Function Classification Score Levels I-III) and neurotypical controls (N = 18; age = 14.6 ± 3.1 years) practiced a knee extension isometric target-matching task. Subsequently, structural equation modelling was used to assess the multivariate relationship between changes in beta (16-22 Hz) and gamma (66-82 Hz) oscillations and the motor performance after practice. The structural equation modelling results suggested youth with cerebral palsy who had a faster reaction time after practice tended to also have a stronger peri-movement beta oscillation in the sensorimotor cortices following practicing. The stronger beta oscillations were inferred to reflect greater certainty in the selected motor plan. The models also indicated that youth with cerebral palsy who overshot the targets less and matched the targets sooner tended to have a stronger execution-related gamma response in the sensorimotor cortices after practice. This stronger gamma response may represent improve activation of the sensorimotor neural generators and/or alterations in the GABAergic interneuron inhibitory-excitatory dynamics. These novel neurophysiological results provide a window on the potential neurological changes governing the practice-related outcomes in the context of the physical therapy.

Inter-individual variability in elliptical and diagonal error distributions potentially relevant to optimal motor planning in football instep kicking

The distribution of motor errors can influence optimal motor planning (where to aim). In football instep kicking, it was shown that ball landing locations exhibit the right-up-left-down elliptical distribution in right-footed kickers and vice versa. However, this was reported as a result of mixed multiple kickers; the individual-level error distribution has been unclear. Here we show substantial inter-individual variability in error shape and error direction in the 30 kicks aimed at a target (1.7 m high, 11.0 m in front) by 27 male football players. All players exhibit right-up-left-down distributions with ellipticity (minor/major radius ratio of the 95% confidence ellipse) ranging from 0.25 to 0.77 and major axis angle ranging from 13 to 67° from the horizontal axis. The mean absolute error and the area of the 95% confidence ellipse are not significantly correlated with major axis angle (ρ ≤ 0.312) and ellipticity (|r| ≤ 0.343). By simulating shots aimed at the top-right and top-left edges of a goal with these observed ranges and normalised ellipse area, we reveal a wide range of probability of shots on goal (top-right: 2.7-fold difference, top-left: 1.5-fold difference) due to inter-individual variability in error shape and direction independent of error size. Further simulation shows that, depending on the shape-direction combination, the aiming points with the same 80% probability of shots on goal change by up to 0.3 m vertically, even for the same minimal error size. We highlight the importance for football players to consider not only accuracy/precision, but also error shape and direction to optimise motor planning.

Regular cannabis use modulates gamma activity in brain regions serving motor control.

People who regularly use cannabis exhibit altered brain dynamics during cognitive control tasks, though the impact of regular cannabis use on the neural dynamics serving motor control remains less understood. We sought to investigate how regular cannabis use modulates the neural dynamics serving motor control. Thirty-four people who regularly use cannabis (cannabis+) and 33 nonusers (cannabis-) underwent structured interviews about their substance use history and performed the Eriksen flanker task to map the neural dynamics serving motor control during high-density magnetoencephalography (MEG). The resulting neural data were transformed into the time-frequency domain to examine oscillatory activity and were imaged using a beamforming approach. MEG sensor-level analyses revealed robust beta (16-24 Hz) and gamma oscillations (66-74 Hz) during motor planning and execution, which were imaged using a beamformer. Both responses peaked in the left primary motor cortex and voxel time series were extracted to evaluate the spontaneous and oscillatory dynamics. Our key findings indicated that the cannabis+ group exhibited weaker spontaneous gamma activity in the left primary motor cortex relative to the cannabis- group, which scaled with cannabis use and behavioral metrics. Interestingly, regular cannabis use was not associated with differences in oscillatory beta and gamma activity, and there were no group differences in spontaneous beta activity. Our findings suggest that regular cannabis use is associated with suppressed spontaneous gamma activity in the left primary motor cortex, which scales with the degree of cannabis use disorder symptomatology and is coupled to behavioral task performance.

Encoding of 2D Self-Centered Plans and World-Centered Positions in the Rat Frontal Orienting Field.

The neural mechanisms of motor planning have been extensively studied in rodents. Preparatory activity in the frontal cortex predicts upcoming choice, but limitations of typical tasks have made it challenging to determine whether the spatial information is in a self-centered direction reference frame or a world-centered position reference frame. Here, we trained male rats to make delayed visually guided orienting movements to six different directions, with four different target positions for each direction, which allowed us to disentangle direction versus position tuning in neural activity. We recorded single unit activity from the rat frontal orienting field (FOF) in the secondary motor cortex, a region involved in planning orienting movements. Population analyses revealed that the FOF encodes two separate 2D maps of space. First, a 2D map of the planned and ongoing movement in a self-centered direction reference frame. Second, a 2D map of the animal's current position on the port wall in a world-centered reference frame. Thus, preparatory activity in the FOF represents self-centered upcoming movement directions, but FOF neurons multiplex both self- and world-reference frame variables at the level of single neurons. Neural network model comparison supports the view that despite the presence of world-centered representations, the FOF receives the target information as self-centered input and generates self-centered planning signals.

Force reflections of auditory and tactile action-effect weighting in motor planning

Most voluntary actions have only few goals, which provides considerable freedom in the selection of action parameters. Recent studies showed that task-irrelevant aspects of the task context influence the motor parameters of the actions in a way which seems to reflect the relative importance of these aspects within the underlying action representation. The present study investigated how the intensity of auditory action-effects affected force exertion patterns in a self-paced action production task. Participants applied force impulses with their index finger on a force-sensitive resistor every three seconds. In four separate conditions, force impulses elicited no sound, or elicited tones with 69, 59 or 49 dB intensity. The results showed that participants applied more force when tone intensity was lower, and when tones were absent. These force differences were also present in the first 60 ms following tone onset, implying that these reflected differences in motor planning. The results are compatible with the notion that actions are represented in terms of their sensory effects, which are weighted differently—presumably to maintain an optimal level of overall auditory and tactile stimulation in the present case. These results hint at the potential usefulness of motor parameters as readouts of action intentions.

A Case Study of Suspected Childhood Apraxia of Sign.

We provide a case report of "Zoe," a 4-year-old deaf child from a deaf signing family, who presented with a possible case of Childhood Apraxia of Sign (CASign). The description is based on reports from the child's speech-language pathologist, her Individualized Education Program report, and a clinician-created sign imitation task. Zoe's sign articulation errors in American Sign Language differed from those reported for typically developing deaf children and were parallel to the types of errors observed for hearing children with childhood apraxia of speech. Specifically, Zoe produced inconsistent errors across signs, substituted more complex handshapes for simple handshapes, made errors on both unmarked (common) and marked (less common) forms, produced articulatory distortions (rather than substitutions), and exhibited "groping" behaviors (a sequence of attempts to move her hands into the correct position). In addition, Zoe sometimes self-corrected her errors by manipulating her own hands, for example, using her left hand to move the thumb of her right hand into the correct position. Zoe's pattern of sign errors is consistent with an underlying deficit in motor planning and/or programming and may constitute the first reported case of CASign.

Independent influences of movement distance and visual distance on Fitts' law.

Fitts' Law is one among a small number of psychophysical laws. However, a fundamental variable in Fitts' Law-the movement distance, D-confounds two quantities: The physical distance the effector has to move to reach a goal, and the visually perceived distance to that goal. While these two quantities are functionally equivalent in everyday motor behavior, decoupling them might improve our understanding of the factors that shape speed-accuracy tradeoffs. Here, we leveraged the phenomenon of visuomotor gain adaptation to de-confound movement and visual distance during goal-directed reaching. We found that movement distance and visual distance can influence movement times, supporting a variant of Fitts' Law that considers both. The weighting of movement versus visual distance was modified by restricting movement range and degrading visual feedback. These results may reflect the role of sensory context in early stages of motor planning. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Motor cortex is responsible for motoric dynamics in striatum and the execution of both skilled and unskilled actions

Striatum and its predominant input, motor cortex, are responsible for the selection and performance of purposive movement, but how their interaction guides these processes is not understood. To establish its neural and behavioral contributions, we bilaterally lesioned motor cortex and recorded striatal activity and reaching performance daily, capturing the lesion's direct ramifications within hours of the intervention. We observed reaching impairment and an absence of striatal motoric activity following lesion of motor cortex, but not parietal cortex control lesions. Although some aspects of performance began to recover after 8-10days, striatal projection and interneuronal dynamics did not-eventually entering a non-motor encoding state that aligned with persisting kinematic control deficits. Lesioned mice also exhibited a profound inability to switch motor plans while locomoting, reminiscent of clinical freezing of gait (FOG). Our results demonstrate the necessity of motor cortex in generating trained and untrained actions as well as striatal motoric dynamics.