Primary motor cortex

…of a sensory stimulus or an overt motor action. Simultaneous recordings allow referencing neurons’ activity to each other and thus detecting signals that are internal to the organism. Further, multi-region simultaneous recordings allow observing how these internal signals are coordinated across the brain. Following this logic in rats performing a perceptual decision-making task, we recorded simultaneously from thousands of neurons across up to 20 brain regions at once. Here we report two internal signals wh

…of mammals in learning arbitrary motor skills, an ability currently unrivaled by artificial systems. How the brain supports these capacities is unclear, as control mechanisms are distributed and interdependent between many brain regions. We make progress on this question by developing a neural network model comprising three major brain systems that are known to play central roles in learned motor control: the cerebellum (CB), primary motor cortex (M1), and associative sensorimotor cortex (ASC). We both leverage

A pivotal challenge in computational neuroscience is identifying sub-populations of neurons that encode behavior, perception, and memory, across varying contexts such as task difficulty or temporal progression. Therefore, analysis tools that provide model interpretability, beyond prediction performance, are essential for studying neuronal population activity. We propose a novel approach conditional-STochastic Gates (c-STG) that combines predictive modeling with contextual feature selection. c-STG comprises two networks: a hypernetwork that maps contextual variables to probabilistic feature sel

Complex dexterous movements, such as reach-and-grasp, are driven by the coordinated activity of multiple brain regions. Each region contributes unique computations while interacting with others to control the movements. To understand the neural principles underlying this behavior across different brain regions, we recorded spiking activity in 10 brain regions while the mice performed a skilled reach-and-grasp task. We identified distinct behavioral phases, each with unique kinematic features. Single neuron analyses showed similar response percentages, with differing response strengths, across

Understanding the neural dynamics underlying motor learning is pivotal for revealing how the brain adapts to acquire new skills. Plasticity in the primary motor cortex is essential for motor skill learning, with Layer 5 pyramidal tract (L5 PT) neurons playing a key role in the process. Previous studies have shown dendritic spines undergo plasticity changes during motor learning, yet the resulting changes at the dendritic level remain unknown. To investigate changes occurring in apical tuft dendrites during motor learning, we performed repeated two-photon calcium imaging of the same L5 PT apic

Motor units (MUs), which compose spinal motor neurons and their innervated muscle fibers, are the fundamental unit of motor control. For nearly one hundred years, researchers have studied how MUs are recruited during movement, and the textbook understanding is that a simplified control strategy is used. A single ‘common drive’ is sent to a muscle’s motor neuron pool, which controls the amount of force that muscle will produce. This understanding has drawn primarily from experiments involving subjects generating static or gradually changing forces. However, recent results, using experiments wit

Adaptation is essential for biological motor control, enabling rapid modifications of control strategies as the environment changes. However, we still lack a unified network-level theory of coordinated motor adaptation. In previous work, we have proposed a multi-area RNN capable of rapid motor adaptation. The network comprises an internal forward model and a planning/control policy network, both of which are continuously modulated by a network that performs contextual inference. The network is meta-trained to maintain proficient control of hand reaches in the face of changing environmental dyn

…Optogenetic inhibition of secondary motor neurons

Functional connectivity has been the focus of many research groups aiming to study the interaction between cells and brain regions. A standard method for analyzing connectivity is to statistically compare pairwise interactions between cells or brain regions across behavioral states or conditions. This methodology ignores the intrinsic properties of functional connectivity as a multivariate and dynamic signal, expressing the correlational configuration of the network. In this talk, I will present a geometric approach, combining Graph Theory and Riemannian Geometry to build "a graph of graphs" a

…magnetic stimulation (TMS) of the primary motor cortex (M1), has been previously explored through simulation methods at different scales. However, the coupling of TMS induced electric fields to neural mass models is still largely unexplored, while previously approached as an arbitrary current pulse [1, 2]. Via multi-scale simulations at the subcellular and neural mass level we study the underlying mechanisms of electromagnetic activation of cortical tissue by TMS. Validation of the coupling model is aided by measurements like E

Rodents rely heavily on somatosensation to explore their environment. The primary somatosensory cortex (S1) contributes to the encoding and perception of tactile stimuli. Although S1 neurons also receive non-tactile inputs, it is unclear whether S1 similarly encodes non-tactile sensory-based behaviour. Whole-cell patch clamp recordings were used to investigate the voltage response of layer 2/3 (L2/3) pyramidal neurons in S1 during performance in either a tactile-based or auditory-based association task in mice. A robust and sustained voltage response was evoked in L2/3 pyramidal neurons during

After stroke, one of the most critical problems for recovering patients is motor dysfunction in the limb contralateral to the affected hemisphere. Several mechanisms may contribute to the recovery of motor function after stroke. One is the recovery of neural pathways within the affected hemisphere. The contribution of the ipsilateral hemisphere is also widely discussed as it may be entirely responsible for motor recovery. The lateralized readiness potential (LRP) is one of the markers of interhemispheric balance during motor preparation. It is a fast negative deflection approximately 200 ms be

…and subsequently transferred to the cortex, facilitating integration into long-term memory networks. Our recent study showed that the precise temporal dynamics of cross-area coupling between prefrontal cortex (PFC) and primary motor cortex (M1) can demarcate the transition to cortical stabilization and task performance, reducing involvement of the hippocampus. Here, we demonstrate the causal role of precise coupling in PFC-M1 sleep slow oscillation (SO) for motor memory stabilization. Using a s

…for dysregulated LC-NA function in motor learning delays of the 16p11.2 deletion (+/-) mouse-model of ASD. We found that reduced NA levels in primary motor cortex (M1) caused delays in motor learning and increased neuronal activity in M1 pyramidal neurons. Both behavioral and neuronal phenotypes were rescued by chemogenetic activation of LC-NA. We next

Understanding how the brain processes motor and tactile imagery is crucial for advancing motor control and rehabilitation.However,there is a knowledge gap in research where EEG recordings are combined with TMS to study the effects of imagery:little is known about tactile imagery (TI) effects.In this study, we aimed to bridge this gap by examining corticospinal excitability during motor imagery (MI) and TI using TMS-EEG.Our previous findings demonstrated that both MI and TI increase corticospinal excitability,with MI having a stronger effect,whereas tactile stimulation (TS) decreases corticospi

Aim: Motor learning significantly impacts daily life, triggering notable changes in the primary motor cortex (M1) and basal ganglia (BG). Dopamine (DA) mediates these changes, with Darpp-32 playing a key role in DA transmission. Although extensively studied in the BG's striatum, Darpp-32's function in the motor cortex remains largely unexplored. This study aims to characterize Darpp-32 in motor cortices, examining cellular expression and its impact on motor behavior, synaptic and structural plasticity.Methods: Anatomical study: Using C57BL/6 mice, we examined Darpp-32 distribution across corti

Our understanding of how sensorimotor information is integrated across dendritic trees is limited by our ability to image these distributed 3D structures in awake animals. We overcome the existing limitations of rapidly measuring 3D dendritic activity and avoiding signal distortion by brain motion artefacts by utilizing our novel nonlinear 3D acousto-optic lens two-photon microscope with real-time 3D brain motion correction and innovative Ca2+ imaging analysis pipelines. This enable the study of sensorimotor information representation in dendritic activity patterns of awake mice during natural

…magnetic stimulation (rTMS) targeting primary motor cortex (M1) have shown promise for the treatment of intractable pain, and high-frequency rTMS (Hf-rTMS) exhibits analgesic effects compared to low-frequency rTMS (Lf-rTMS), while its analgesic mechanism is unknow

…fiber density in networks involved in motor control, language and vision (Fig. 1). However, individual genetic variants disposing to dyslexia

…as a potential therapeutic to restore motor impairment

…cortical excitability in the cerebral cortex just below the magnet as well as modulate the function of the cerebral cortex contralateral to the stimulation side via the brain network. tSMS is a promising neuromodulatory technique for a safe, low-cost, and easy therapeutic tool. However, the neurophysiological mechanisms how local tSMS changes the whole brain net

Single-pulse transcranial magnetic stimulation (spTMS) applied to the primary motor cortex (M1) is widely used to assess corticospinal excitability through motor evoked potentials (MEPs). While trial-by-trial variability in MEP amplitude is thought to reflect dynamic shifts in cortical excitability, implications and neural underpinnings of gradual changes in MEP amplitude over the course of a spTMS session remain unexplored. We addressed this gap by investigating the relationship between slow MEP amplitude fluctuations and shifts in electroencephalography (EEG)-derived excitation/inhibition (E

Lateralization of motor skills such as hand preference is a common trait across various species, including humans and rodents. It's well known that humans can alter their dominant hand through training, a process often associated with psychological stress and the potential for developmental issues, including language impairments. Yet, the neural mechanisms underlying the hand switching remain largely obscure. Our research delves into this phenomenon in mice, revealing that they can also alter their hand preference via corrective training. We focused on the basal forebrain's cholinergic system,

…cells are also present in the neocortex, though seemingly less frequent than in the hippocampu