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ELife Feb 2022The primary motor cortex (M1) is known to be a critical site for movement initiation and motor learning. Surprisingly, it has also been shown to possess reward-related...
The primary motor cortex (M1) is known to be a critical site for movement initiation and motor learning. Surprisingly, it has also been shown to possess reward-related activity, presumably to facilitate reward-based learning of new movements. However, whether reward-related signals are represented among different cell types in M1, and whether their response properties change after cue-reward conditioning remains unclear. Here, we performed longitudinal in vivo two-photon Ca imaging to monitor the activity of different neuronal cell types in M1 while mice engaged in a classical conditioning task. Our results demonstrate that most of the major neuronal cell types in M1 showed robust but differential responses to both the conditioned cue stimulus (CS) and reward, and their response properties undergo cell-type-specific modifications after associative learning. PV-INs' responses became more reliable to the CS, while VIP-INs' responses became more reliable to reward. Pyramidal neurons only showed robust responses to novel reward, and they habituated to it after associative learning. Lastly, SOM-INs' responses emerged and became more reliable to both the CS and reward after conditioning. These observations suggest that cue- and reward-related signals are preferentially represented among different neuronal cell types in M1, and the distinct modifications they undergo during associative learning could be essential in triggering different aspects of local circuit reorganization in M1 during reward-based motor skill learning.
Topics: Animals; Female; Learning; Male; Mice; Motor Cortex; Neurons
PubMed: 35113017
DOI: 10.7554/eLife.72549 -
Proceedings of the National Academy of... Feb 1998Behavioral and neurophysiological studies suggest that skill learning can be mediated by discrete, experience-driven changes within specific neural representations... (Review)
Review
Behavioral and neurophysiological studies suggest that skill learning can be mediated by discrete, experience-driven changes within specific neural representations subserving the performance of the trained task. We have shown that a few minutes of daily practice on a sequential finger opposition task induced large, incremental performance gains over a few weeks of training. These gains did not generalize to the contralateral hand nor to a matched sequence of identical component movements, suggesting that a lateralized representation of the learned sequence of movements evolved through practice. This interpretation was supported by functional MRI data showing that a more extensive representation of the trained sequence emerged in primary motor cortex after 3 weeks of training. The imaging data, however, also indicated important changes occurring in primary motor cortex during the initial scanning sessions, which we proposed may reflect the setting up of a task-specific motor processing routine. Here we provide behavioral and functional MRI data on experience-dependent changes induced by a limited amount of repetitions within the first imaging session. We show that this limited training experience can be sufficient to trigger performance gains that require time to become evident. We propose that skilled motor performance is acquired in several stages: "fast" learning, an initial, within-session improvement phase, followed by a period of consolidation of several hours duration, and then "slow" learning, consisting of delayed, incremental gains in performance emerging after continued practice. This time course may reflect basic mechanisms of neuronal plasticity in the adult brain that subserve the acquisition and retention of many different skills.
Topics: Adult; Animals; Brain Mapping; Humans; Learning; Magnetic Resonance Imaging; Motor Cortex; Psychomotor Performance; Time Factors
PubMed: 9448252
DOI: 10.1073/pnas.95.3.861 -
Acta Neurochirurgica Nov 2023Motor cortex stimulation (MCS) represents a treatment option for refractory trigeminal neuralgia (TGN). Usually, patients need to be awake during surgery to confirm a...
Positioning of epidural electrode for motor cortex stimulation in general anesthesia based on intraoperative electrophysiological monitoring to treat refractory trigeminal neuropathic pain.
BACKGROUND
Motor cortex stimulation (MCS) represents a treatment option for refractory trigeminal neuralgia (TGN). Usually, patients need to be awake during surgery to confirm a correct position of the epidural electrode above the motor cortex, reducing patient's comfort.
METHOD
Epidural cortical mapping (ECM) and motor evoked potentials (MEPs) were intraoperatively performed for correct localization of motor cortex under general anesthesia that provided comparable results to test stimulation after letting the patient to be awake during the operation.
CONCLUSION
Intraoperative ECM and MEPs facilitate a confirmation of correct MCS-electrode position above the motor cortex allowing the MCS-procedure to be performed under general anesthesia.
Topics: Humans; Trigeminal Neuralgia; Motor Cortex; Electrodes, Implanted; Neuralgia; Anesthesia, General
PubMed: 37713173
DOI: 10.1007/s00701-023-05801-5 -
Ciba Foundation Symposium 1987In behaving monkeys the effects of motor cortex cells on muscles are inferred from two quite different types of 'correlational' evidence: their coactivation and... (Review)
Review
In behaving monkeys the effects of motor cortex cells on muscles are inferred from two quite different types of 'correlational' evidence: their coactivation and cross-correlation. Many precentral cells are coactivated with limb muscles, suggesting that they make a proportional contribution to muscle activity; however, such coactivation is typically quite flexible, and can be changed by operantly conditioning the dissociation of cell and muscle activity. Cross-correlating cells and muscles by spike-triggered averaging of the electromyogram (EMG) shows that certain cells produce short-latency post-spike facilitation of EMG; this correlational linkage is relatively fixed under different behavioural conditions and its time course suggests it is mediated by a corticomotoneuronal (CM) synaptic connection. CM cells typically facilitate a set of coactivated agonist muscles, and some also inhibit their antagonists. The firing patterns of CM cells can differ significantly from those of their target muscles. During ramp-and-hold wrist responses most CM cells discharge a phasic burst that precedes target muscle onset and that contributes to changes in muscle activity. At low force levels many CM cells are activated without their target motor units. Conversely, many CM cells are paradoxically inactive during rapid forceful movements that vigorously activate their target muscles; they appear to be preferentially active during finely controlled movements. Thus CM cells, with a fixed correlational linkage to their target muscles, may be recruited without their target muscles, and vice versa.
Topics: Animals; Haplorhini; Motor Cortex; Motor Neurons; Muscles; Primates
PubMed: 3123173
DOI: 10.1002/9780470513545.ch7 -
ELife May 2024Cholecystokinin (CCK) is an essential modulator for neuroplasticity in sensory and emotional domains. Here, we investigated the role of CCK in motor learning using a...
Cholecystokinin (CCK) is an essential modulator for neuroplasticity in sensory and emotional domains. Here, we investigated the role of CCK in motor learning using a single pellet reaching task in mice. Mice with a knockout of gene () or blockade of CCK-B receptor (CCKBR) showed defective motor learning ability; the success rate of retrieving reward remained at the baseline level compared to the wildtype mice with significantly increased success rate. We observed no long-term potentiation upon high-frequency stimulation in the motor cortex of mice, indicating a possible association between motor learning deficiency and neuroplasticity in the motor cortex. In vivo calcium imaging demonstrated that the deficiency of CCK signaling disrupted the refinement of population neuronal activity in the motor cortex during motor skill training. Anatomical tracing revealed direct projections from CCK-expressing neurons in the rhinal cortex to the motor cortex. Inactivation of the CCK neurons in the rhinal cortex that project to the motor cortex bilaterally using chemogenetic methods significantly suppressed motor learning, and intraperitoneal application of CCK4, a tetrapeptide CCK agonist, rescued the motor learning deficits of mice. In summary, our results suggest that CCK, which could be provided from the rhinal cortex, may surpport motor skill learning by modulating neuroplasticity in the motor cortex.
Topics: Animals; Male; Mice; Cholecystokinin; Learning; Mice, Knockout; Motor Cortex; Motor Skills; Neuronal Plasticity
PubMed: 38700136
DOI: 10.7554/eLife.83897 -
Ciba Foundation Symposium 1987The precentral motor cortex in the macaque is defined here as that portion of the precentral motor-sensory areas which projects to the intermediate zone and motor... (Review)
Review
The precentral motor cortex in the macaque is defined here as that portion of the precentral motor-sensory areas which projects to the intermediate zone and motor neuronal cell groups in the spinal cord and their bulbar counterparts, i.e. the lateral reticular formation and motor nuclei of the lower brainstem. In this respect the precentral motor cortical areas differ from postcentral areas such that the descending projections from the latter are focused on the spinal dorsal horn and the spinal V complex. Differences in the distribution of the corticospinal fibres in different species are mentioned and differences in findings obtained by means of different tracing techniques are discussed. The projections from the precentral motor cortex to various brain-stem cell groups are also discussed and the areas of origin of these projections are delineated. The presence of branching neurons distributing collaterals to several of these areas is considered.
Topics: Animals; Brain Stem; Cats; Macaca; Motor Cortex; Motor Neurons; Neural Pathways; Spinal Cord
PubMed: 3322721
DOI: 10.1002/9780470513545.ch5 -
Acta Neurobiologiae Experimentalis 1996This paper reviews studies that investigate conditions resulting in long-lasting modifications of synaptic efficacy in horizontal connections within layers II/III of... (Review)
Review
This paper reviews studies that investigate conditions resulting in long-lasting modifications of synaptic efficacy in horizontal connections within layers II/III of adult rat motor cortex using the in vitro slice preparation. Long-term potentiation (LTP) was induced by high frequency theta burst stimulation (TBS) when local synaptic inhibition was transiently suppressed by bicuculline methiodide application at the recording site immediately prior to TBS of the horizontal pathway. Without bicuculline, TBS failed to produce LTP. LTP could also be induced without Bic application by conjoint TBS of horizontal and vertical (ascending) inputs. By contrast, long-term depression (LTD) of horizontal transmission was induced by 10 min of 2 Hz stimulation. Depressed horizontal connections nevertheless retained the capability for synaptic strength increases. These studies indicate that synaptic modification across horizontally connected neurones is regulated both by the arrangement of their intrinsic circuits and by the availability of mechanisms for modification at individual synapses. Activity dependent forms of synaptic plasticity operating within horizontal connections may form a spatial substrate and mechanism for experience-dependent regulation of cortical representations.
Topics: Animals; Long-Term Potentiation; Motor Cortex; Neural Pathways; Neuronal Plasticity; Rats
PubMed: 8787200
DOI: 10.55782/ane-1996-1143 -
Journal of Neurophysiology Oct 2018Cholinergic inputs to cortex modulate plasticity and sensory processing, yet little is known about their role in motor control. Here, we show that cholinergic signaling...
Cholinergic inputs to cortex modulate plasticity and sensory processing, yet little is known about their role in motor control. Here, we show that cholinergic signaling in a songbird vocal motor cortical area, the robust nucleus of the arcopallium (RA), is required for song learning. Reverse microdialysis of nicotinic and muscarinic receptor antagonists into RA in juvenile birds did not significantly affect syllable timing or acoustic structure during vocal babbling. However, chronic blockade over weeks reduced singing quantity and impaired learning, resulting in an impoverished song with excess variability, abnormal acoustic features, and reduced similarity to tutor song. The demonstration that cholinergic signaling in a motor cortical area is required for song learning motivates the songbird as a tractable model system to identify roles of the basal forebrain cholinergic system in motor control. NEW & NOTEWORTHY Cholinergic inputs to cortex are evolutionarily conserved and implicated in sensory processing and synaptic plasticity. However, functions of cholinergic signals in motor areas are understudied and poorly understood. Here, we show that cholinergic signaling in a songbird vocal motor cortical area is not required for normal vocal variability during babbling but is essential for developmental song learning. Cholinergic modulation of motor cortex is thus required for learning but not for the ability to sing.
Topics: Animals; Cholinergic Antagonists; Cholinergic Neurons; Finches; Learning; Male; Motor Cortex; Synaptic Transmission; Vocalization, Animal
PubMed: 29995601
DOI: 10.1152/jn.00078.2018 -
Nature Apr 2016Neural activity maintains representations that bridge past and future events, often over many seconds. Network models can produce persistent and ramping activity, but...
Neural activity maintains representations that bridge past and future events, often over many seconds. Network models can produce persistent and ramping activity, but the positive feedback that is critical for these slow dynamics can cause sensitivity to perturbations. Here we use electrophysiology and optogenetic perturbations in the mouse premotor cortex to probe the robustness of persistent neural representations during motor planning. We show that preparatory activity is remarkably robust to large-scale unilateral silencing: detailed neural dynamics that drive specific future movements were quickly and selectively restored by the network. Selectivity did not recover after bilateral silencing of the premotor cortex. Perturbations to one hemisphere are thus corrected by information from the other hemisphere. Corpus callosum bisections demonstrated that premotor cortex hemispheres can maintain preparatory activity independently. Redundancy across selectively coupled modules, as we observed in the premotor cortex, is a hallmark of robust control systems. Network models incorporating these principles show robustness that is consistent with data.
Topics: Animals; Brain Mapping; Corpus Callosum; Executive Function; Female; Light; Male; Memory, Short-Term; Mice; Models, Neurological; Motor Cortex; Movement; Neurons; Optogenetics
PubMed: 27074502
DOI: 10.1038/nature17643 -
Brain Research Apr 1976Punctate intracortical stimulation of the motor cortex (areas 4 and 6), with parallel observation of the induced movements, permits description of a fine somatotopic...
Punctate intracortical stimulation of the motor cortex (areas 4 and 6), with parallel observation of the induced movements, permits description of a fine somatotopic organization of the motor control areas for different parts of the musculature in freely moving adult cats. The results show that movements produced by electrical stimulation of the motor cortex are always single and non-repetitive, regardless of the duration and intensity of the stimulation. These movements are restricted to a very precise part of the musculature, and experiments show that this localization is related to the exact position of the tip of the stimulating electrode in the motor cortex. Other experimental data show that motor responses which disturb the animal's equilibrium are accompanied by postural adjustments. Stimulation of the cerebral cortex permits the definition of a separate motor control area for each part of the cat musculature, with an individual control area for each of the joints of the forelimb. This was not possible for the hindlimb, which is always activated in its entirety. These results establish a new representation of the somatotopic organization of the cat motor cortex. This diagram shows that area 6 controls the more axial parts of the musculature, while area 4 controls the proximal and distal parts of the limb muscles. This map was compared to numerous previous data on the somatotopic organization in the cat motor cortex, especially to the map of Woolsey.
Topics: Animals; Brain Mapping; Cats; Electric Stimulation; Motor Cortex
PubMed: 1260454
DOI: 10.1016/0006-8993(76)90590-4