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Langlois ET, Bennequin D, de Marco G. Role of the Cerebellum in the Construction of Functional and Geometrical Spaces. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01693-y. [PMID: 38625534 DOI: 10.1007/s12311-024-01693-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/10/2024] [Indexed: 04/17/2024]
Abstract
The perceptual and motor systems appear to have a set of movement primitives that exhibit certain geometric and kinematic invariances. Complex patterns and mental representations can be produced by (re)combining some simple motor elements in various ways using basic operations, transformations, and respecting a set of laws referred to as kinematic laws of motion. For example, point-to-point hand movements are characterized by straight hand paths with single-peaked-bell-shaped velocity profiles, whereas hand speed profiles for curved trajectories are often irregular and more variable, with speed valleys and inflections extrema occurring at the peak curvature. Curvature and speed are generically related by the 2/3 power law. Mathematically, such laws can be deduced from a combination of Euclidean, affine, and equi-affine geometries, whose neural correlates have been partially detected in various brain areas including the cerebellum and the basal ganglia. The cerebellum has been found to play an important role in the control of coordination, balance, posture, and timing over the past years. It is also assumed that the cerebellum computes forward internal models in relationship with specific cortical and subcortical brain regions but its motor relationship with the perceptual space is unclear. A renewed interest in the geometrical and spatial role of the cerebellum may enable a better understanding of its specific contribution to the action-perception loop and behavior's adaptation. In this sense, we complete this overview with an innovative theoretical framework that describes a possible implementation and selection by the cerebellum of geometries adhering to different mathematical laws.
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Affiliation(s)
- Eya Torkhani Langlois
- LINP2, UPL, Université Paris Nanterre, 200 avenue de la République, Nanterre, 92000, France
| | - Daniel Bennequin
- Equipe Géométrie et Dynamique, Paris-Cité, UFR de Mathématiques, Bâtiment Sophie Germain, 8 place Aurélie Nemours, Paris, 75013, France
| | - Giovanni de Marco
- LINP2, UPL, Université Paris Nanterre, 200 avenue de la République, Nanterre, 92000, France.
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2
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Falaki A, Cuadra C, Lewis MM, Prado-Rico JM, Huang X, Latash ML. Multi-muscle synergies in preparation for gait initiation in Parkinson's disease. Clin Neurophysiol 2023; 154:12-24. [PMID: 37524005 DOI: 10.1016/j.clinph.2023.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/20/2023] [Accepted: 06/25/2023] [Indexed: 08/02/2023]
Abstract
OBJECTIVE We investigated changes in indices of muscle synergies prior to gait initiation and the effects of gaze shift in patients with Parkinson's disease (PD). A long-term objective of the study is to develop a method for quantitative assessment of gait-initiation problems in PD. METHODS PD patients without clinical signs of postural instability and two control groups (age-matched and young) performed a gait initiation task in a self-paced manner, with and without a quick prior gaze shift produced by turning the head. Muscle groups with parallel scaling of activation levels (muscle modes) were identified as factors in the muscle activation space. Synergy index stabilizing center of pressure trajectory in the anterior-posterior and medio-lateral directions (indices of stability) was quantified in the muscle mode space. A drop in the synergy index in preparation to gait initiation (anticipatory synergy adjustment, ASA) was quantified. RESULTS Compared to the control groups, PD patients showed significantly smaller synergy indices and ASA for both directions of the center of pressure shift. Both PD and age-matched controls, but not younger controls, showed detrimental effects of the prior gaze shift on the ASA indices. CONCLUSIONS PD patients without clinically significant posture or gait disorders show impaired stability of the center of pressure and its diminished adjustment during gait initiation. SIGNIFICANCE The indices of stability and ASA may be useful to monitor pre-clinical gait disorders, and lower ASA may be relevant to emergence of freezing of gait in PD.
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Affiliation(s)
- Ali Falaki
- Department of Neurosciences, University of Montreal, Montreal, Quebec, Canada
| | - Cristian Cuadra
- Department of Physical Therapy, Emory University, Atlanta, GA, USA; Exercise and Rehabilitation Sciences Laboratory, School of Physical Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, 7591538 Santiago, Chile
| | - Mechelle M Lewis
- Department of Neurology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Pharmacology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA
| | - Janina M Prado-Rico
- Department of Neurology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA
| | - Xuemei Huang
- Department of Neurology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Pharmacology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Radiology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Neurosurgery, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA.
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Farjami S, Alexander RPD, Bowie D, Khadra A. Switching in Cerebellar Stellate Cell Excitability in Response to a Pair of Inhibitory/Excitatory Presynaptic Inputs: A Dynamical System Perspective. Neural Comput 2020; 32:626-658. [DOI: 10.1162/neco_a_01261] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Cerebellar stellate cells form inhibitory synapses with Purkinje cells, the sole output of the cerebellum. Upon stimulation by a pair of varying inhibitory and fixed excitatory presynaptic inputs, these cells do not respond to excitation (i.e., do not generate an action potential) when the magnitude of the inhibition is within a given range, but they do respond outside this range. We previously used a revised Hodgkin–Huxley type of model to study the nonmonotonic first-spike latency of these cells and their temporal increase in excitability in whole cell configuration (termed run-up). Here, we recompute these latency profiles using the same model by adapting an efficient computational technique, the two-point boundary value problem, that is combined with the continuation method. We then extend the study to investigate how switching in responsiveness, upon stimulation with presynaptic inputs, manifests itself in the context of run-up. A three-dimensional reduced model is initially derived from the original six-dimensional model and then analyzed to demonstrate that both models exhibit type 1 excitability possessing a saddle-node on an invariant cycle (SNIC) bifurcation when varying the amplitude of [Formula: see text]. Using slow-fast analysis, we show that the original model possesses three equilibria lying at the intersection of the critical manifold of the fast subsystem and the nullcline of the slow variable [Formula: see text] (the inactivation of the A-type K[Formula: see text] channel), the middle equilibrium is of saddle type with two-dimensional stable manifold (computed from the reduced model) acting as a boundary between the responsive and non-responsive regimes, and the (ghost of) SNIC is formed when the [Formula: see text]-nullcline is (nearly) tangential to the critical manifold. We also show that the slow dynamics associated with (the ghost of) the SNIC and the lower stable branch of the critical manifold are responsible for generating the nonmonotonic first-spike latency. These results thus provide important insight into the complex dynamics of stellate cells.
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Affiliation(s)
- Saeed Farjami
- Department of Physiology, McGill University, Montreal, QC Canada H3G 1Y6
| | - Ryan P. D. Alexander
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC Canada H3G 1Y6
| | - Derek Bowie
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC Canada H3G 1Y6
| | - Anmar Khadra
- Department of Physiology, McGill University, Montreal, QC Canada H3G 1Y6
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Associating transcription factors and conserved RNA structures with gene regulation in the human brain. Sci Rep 2017; 7:5776. [PMID: 28720872 PMCID: PMC5516038 DOI: 10.1038/s41598-017-06200-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/20/2017] [Indexed: 02/06/2023] Open
Abstract
Anatomical subdivisions of the human brain can be associated with different neuronal functions. This functional diversification is reflected by differences in gene expression. By analyzing post-mortem gene expression data from the Allen Brain Atlas, we investigated the impact of transcription factors (TF) and RNA secondary structures on the regulation of gene expression in the human brain. First, we modeled the expression of a gene as a linear combination of the expression of TFs. We devised an approach to select robust TF-gene interactions and to determine localized contributions to gene expression of TFs. Among the TFs with the most localized contributions, we identified EZH2 in the cerebellum, NR3C1 in the cerebral cortex and SRF in the basal forebrain. Our results suggest that EZH2 is involved in regulating ZIC2 and SHANK1 which have been linked to neurological diseases such as autism spectrum disorder. Second, we associated enriched regulatory elements inside differentially expressed mRNAs with RNA secondary structure motifs. We found a group of purine-uracil repeat RNA secondary structure motifs plus other motifs in neuron related genes such as ACSL4 and ERLIN2.
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Mosconi MW, Wang Z, Schmitt LM, Tsai P, Sweeney JA. The role of cerebellar circuitry alterations in the pathophysiology of autism spectrum disorders. Front Neurosci 2015; 9:296. [PMID: 26388713 PMCID: PMC4555040 DOI: 10.3389/fnins.2015.00296] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/06/2015] [Indexed: 01/23/2023] Open
Abstract
The cerebellum has been repeatedly implicated in gene expression, rodent model and post-mortem studies of autism spectrum disorder (ASD). How cellular and molecular anomalies of the cerebellum relate to clinical manifestations of ASD remains unclear. Separate circuits of the cerebellum control different sensorimotor behaviors, such as maintaining balance, walking, making eye movements, reaching, and grasping. Each of these behaviors has been found to be impaired in ASD, suggesting that multiple distinct circuits of the cerebellum may be involved in the pathogenesis of patients' sensorimotor impairments. We will review evidence that the development of these circuits is disrupted in individuals with ASD and that their study may help elucidate the pathophysiology of sensorimotor deficits and core symptoms of the disorder. Preclinical studies of monogenetic conditions associated with ASD also have identified selective defects of the cerebellum and documented behavioral rescues when the cerebellum is targeted. Based on these findings, we propose that cerebellar circuits may prove to be promising targets for therapeutic development aimed at rescuing sensorimotor and other clinical symptoms of different forms of ASD.
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Affiliation(s)
- Matthew W Mosconi
- Clinical Child Psychology Program and Schiefelbusch Institute for Life Span Studies, University of Kansas Lawrence, KS, USA ; Center for Autism and Developmental Disabilities, University of Texas Southwestern Dallas, TX, USA ; Department of Psychiatry, University of Texas Southwestern Dallas, TX, USA ; Department of Pediatrics, University of Texas Southwestern Dallas, TX, USA
| | - Zheng Wang
- Center for Autism and Developmental Disabilities, University of Texas Southwestern Dallas, TX, USA ; Department of Psychiatry, University of Texas Southwestern Dallas, TX, USA
| | - Lauren M Schmitt
- Center for Autism and Developmental Disabilities, University of Texas Southwestern Dallas, TX, USA ; Department of Psychiatry, University of Texas Southwestern Dallas, TX, USA
| | - Peter Tsai
- Center for Autism and Developmental Disabilities, University of Texas Southwestern Dallas, TX, USA ; Department of Psychiatry, University of Texas Southwestern Dallas, TX, USA ; Department of Pediatrics, University of Texas Southwestern Dallas, TX, USA ; Department of Neurology and Neurotherapeutics, University of Texas Southwestern Dallas, TX, USA ; Department of Neuroscience, University of Texas Southwestern Dallas, TX, USA
| | - John A Sweeney
- Center for Autism and Developmental Disabilities, University of Texas Southwestern Dallas, TX, USA ; Department of Psychiatry, University of Texas Southwestern Dallas, TX, USA ; Department of Pediatrics, University of Texas Southwestern Dallas, TX, USA
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Nowak DA, Topka H, Timmann D, Boecker H, Hermsdörfer J. The role of the cerebellum for predictive control of grasping. THE CEREBELLUM 2007; 6:7-17. [PMID: 17366262 DOI: 10.1080/14734220600776379] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Predictive control of grasping forces when manipulating objects in the environment is suggested to reflect internal models that capture the causal relationship between actions and their consequences. The anatomical correlate of predictive control of grasping within the central nervous system is not completely understood. One structure which has been related to the neural representation of internal models is the cerebellum. Given its stereotyped cytoarchitecture, the widespread connections with cortical and subcortical sensory-motor structures and the neural activity of cerebellar Purkinje cells during sensory-motor tasks, the cerebellum has long been considered to play a major role in the establishment and maintenance of sensory-motor representations related to voluntary movement. Such representations are necessary to predict the consequences of our own movements. Here we review theoretical concepts, electrophysiological, imaging and behavioural data suggesting the cerebellum to be the anatomical and functional correlate of internal models relevant for predictive control of grasping.
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Affiliation(s)
- Dennis A Nowak
- Department of Neurology, University of Cologne and Institute of Medicine, Research Center Jülich, Jerpener Strasse 62, D-50924 Cologne, Germany.
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Townsend BR, Paninski L, Lemon RN. Linear Encoding of Muscle Activity in Primary Motor Cortex and Cerebellum. J Neurophysiol 2006; 96:2578-92. [PMID: 16790591 DOI: 10.1152/jn.01086.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The activity of neurons in primary motor cortex (M1) and cerebellum is known to correlate with extrinsic movement parameters, including hand position and velocity. Relatively few studies have addressed the encoding of intrinsic parameters, such as muscle activity. Here we applied a generalized regression analysis to describe the relationship of neurons in M1 and cerebellar dentate nucleus to electromyographic (EMG) activity from hand and forearm muscles, during performance of precision grip by macaque monkeys. We showed that cells in both M1 and dentate encode muscle activity in a linear fashion, and that EMG signals provide predictions of neural discharge that are equally accurate to those from kinematic information under these task conditions. Neural activity in M1 was significantly more correlated with both EMG and kinematic signals than was activity in dentate nucleus. Furthermore, the analysis enabled us to look at the temporal properties of muscle encoding. Cells were broadly tuned to muscle activity as a function of the lag between spiking and EMG and there was considerable heterogeneity in the optimal delay among individual neurons. However, a single lag (40 ms) was generally sufficient to provide good fits. Finally, incorporating spike history effects in our model offered no advantage in predicting novel spike trains, reinforcing the simple nature of the muscle encoding that we observed here.
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Affiliation(s)
- Benjamin R Townsend
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London UK WC1N 3BG
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Abstract
Our concepts about the organization and functions of the cerebellum have changed substantially in the last 10 years. In recent studies, we used transneuronal virus tracing techniques to demonstrate that the output of the cerebellum of primates projects via the thalamus not only to its classical motor target, the primary motor cortex, but also to "nonmotor" cortical areas in the prefrontal and posterior parietal cortex. We found that dentate neurons projecting to different cortical areas originated from localized regions of the nucleus which we termed "output channels." To compare the locations of the output channels projecting to different cortical targets, we have created an unfolded map of the dentate. This unfolded map revealed that dentate output channels were segregated into spatially separate "motor" and "nonmotor" domains. The output channels in the motor domain exclusively targeted primary motor and premotor areas of the cerebral cortex. These channels were localized in the dorsal portion of the dentate. The output channels in the nonmotor domain projected to prefrontal and posterior parietal cortical areas. The nonmotor domain was confined to the ventral portion of the dentate. In recent studies, we defined a unique molecular marker, monoclonal antibody 8B3, which appears to differentially "recognize" these two domains. Taken together, our results suggest that dentate output is organized according to the functional capabilities of its cortical targets. This organization provides the dentate nucleus with the anatomical substrate to influence not only the control of movement, but also cognitive, higher-order executive and visuospatial functions.
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Affiliation(s)
- Richard P Dum
- Pittsburgh Veterans Affairs Medical Center, Pittsburgh, Pennsylvania, USA
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Tsekhmistrenko TA. Structural transformations in the human cerebellar cortex from birth to the age of three years. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 1996; 26:579-83. [PMID: 9121637 DOI: 10.1007/bf02359503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- T A Tsekhmistrenko
- Laboratory of Functional Morphology, Institute of Age Physiology, Russian Academy of Education, Moscow
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Brooks V, Hilperath F, Brooks M, Ross HG, Freund HJ. Learning "what" and "how" in a human motor task. Learn Mem 1995; 2:225-42. [PMID: 10467577 DOI: 10.1101/lm.2.5.225] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We studied the development of implicit and of verbally declared knowledge for normal human subjects who learned an unfamiliar motor task in one learning session. The exploratory nature of motor learning and a special period for optimizing skill were followed in real time. Subjects understood the goal for task success, but they had to learn a motor strategy of what pattern of serial movements to make and the tactics of how much to scale their amplitudes and timing. We compared the time course for acquiring tactical skill with that for acquiring knowledge of strategy and of tactics, and their necessary cues. Implicit and declarative knowledge were distinguished from one another by correlating subjects' verbal self-reports with movement kinematics and their results. Implicit generation of the correct strategy and of the tactics developed in an exploratory manner from the beginning of the learning session. Implicit strategy learning soon gave way to conscious efforts, but tactical learning remained implicit until its first unambiguous verbal declaration (with one exception). First strategy declarations were voiced before those for tactics, during trial-and-error learning that did not require task success, and referred to reversing the direction of hand movements (one exception). In contrast, first declarations of tactics almost always required actual or imminent success, referred to when direction was to be reversed, and it was achieved near the top of a sigmoid learning curve that rose to tactical skill (with one exception). During the sigmoid rise, movement amplitudes and timing were optimized in a distinct manner, although tactics usually adapted thereafter to movements of more moderate speed that could still be successful.
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Affiliation(s)
- V Brooks
- Department of Physiology, University of Western Ontario, London, Canada
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Burlachkova NI, Gurskaya NZ, Kozlovskaya IB, Markova ED. Impaired step-tracking control in patients with cerebellar and pyramidal lesions. NEUROPHYSIOLOGY+ 1988. [DOI: 10.1007/bf01056618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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