scholarly journals Cerebellar contribution to preparatory activity in motor neocortex

2018 ◽  
Author(s):  
Francois P. Chabrol ◽  
Antonin Blot ◽  
Thomas D. Mrsic-Flogel
Keyword(s):  
Motor Cortex ◽  
Feedback Loop ◽  
Dentate Nucleus ◽  
Excitatory Input ◽  
Climbing Fibre ◽  
Reward Delivery ◽  
Preparatory Activity ◽  
Output Neurons ◽  
Cell Firing ◽  
Motor Thalamus

In motor neocortex, preparatory activity predictive of specific movements is maintained by a positive feedback loop with the thalamus. Motor thalamus receives excitatory input from the cerebellum, which learns to generate predictive signals for motor control. The contribution of this pathway to neocortical preparatory signals remains poorly understood. Here we show that in a virtual reality conditioning task, cerebellar output neurons in the dentate nucleus exhibit preparatory activity similar to that in anterolateral motor cortex prior to reward acquisition. Silencing activity in dentate nucleus by photoactivating inhibitory Purkinje cells in the cerebellar cortex caused robust, short-latency suppression of preparatory activity in anterolateral motor cortex. Our results suggest that preparatory activity is controlled by a learned decrease of Purkinje cell firing in advance of reward under supervision of climbing fibre inputs signalling reward delivery. Thus, cerebellar computations exert a powerful influence on preparatory activity in motor neocortex.

scholarly journals Distinct descending motor cortex pathways and their roles in movement

2017 ◽  
Author(s):  
Michael N. Economo ◽  
Sarada Viswanathan ◽  
Bosiljka Tasic ◽  
Erhan Bas ◽  
Johan Winnubst ◽  
...  
Keyword(s):  
Motor Control ◽  
Motor Cortex ◽  
Pyramidal Tract ◽  
Transcriptional Profiling ◽  
Motor Command ◽  
Delayed Response ◽  
Preparatory Activity ◽  
Output Neurons ◽  
Response Task ◽  
Delayed Response Task

ABSTRACTActivity in motor cortex predicts specific movements, seconds before they are initiated. This preparatory activity has been observed in L5 descending ‘pyramidal tract’ (PT) neurons. A key question is how preparatory activity can be maintained without causing movement, and how preparatory activity is eventually converted to a motor command to trigger appropriate movements. We used single cell transcriptional profiling and axonal reconstructions to identify two types of PT neuron. Both types share projections to multiple targets in the basal ganglia and brainstem. One type projects to thalamic regions that connect back to motor cortex. In a delayed-response task, these neurons produced early preparatory activity that persisted until the movement. The second type projects to motor centers in the medulla and produced late preparatory activity and motor commands. These results indicate that two motor cortex output neurons are specialized for distinct roles in motor control.

GABAergic and Glutamatergic Modulation of Spontaneous and Motor-Cortex-Evoked Complex Spike Activity

2002 ◽  
Vol 87 (4) ◽  
pp. 1993-2008 ◽  
Author(s):  
Eric J. Lang
Keyword(s):  
Motor Cortex ◽  
Banding Pattern ◽  
Spike Activity ◽  
Afferent Input ◽  
Excitatory Input ◽  
Relative Strength ◽  
Spike Synchrony ◽  
Complex Spike ◽  
Electrotonic Coupling ◽  
Inferior Olivary

Olivocerebellar activity is organized such that synchronous complex spikes occur primarily among Purkinje cells located within the same parasagittally oriented strip of cortex. Previous findings have shown that this synchrony distribution is modulated by the release of GABA and glutamate within the inferior olive, which probably act by controlling the efficacy of the electrotonic coupling between olivary neurons. The relative strengths of these two neurotransmitters in modulating the patterns of synchrony were compared by obtaining multiple electrode recordings of spontaneous crus 2a complex spike activity during intraolivary injection of solutions containing a GABAA (picrotoxin) and/or AMPA [1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide disodium (NBQX)] receptor antagonist. Injection of either antagonist led to increased synchrony between cells located within the same parasagittally oriented ≈250-μm-wide cortical strip. Picrotoxin also increased complex spike synchrony among cells located in different cortical strips, leading to a less prominent banding pattern, whereas injections of NBQX tended to decrease complex spike synchrony among such cells, enhancing the banding pattern. The relative strength of these two classes of olivary afferents was assessed by first injecting one of the antagonists alone and then in combination with the other. The enhanced banding pattern of complex spike synchrony following injection of NBQX alone remained during the subsequent combined injection of both antagonists. Furthermore, the widespread synchronization of complex spike activity following injection of picrotoxin alone was partially or completely reversed by combined injection of picrotoxin and NBQX. Changes in the climbing fiber reflex induced by the intraolivary injections paralleled the changes observed for spontaneous complex spike activity, indicating that the effects of picrotoxin and NBQX on the synchrony distribution reflect changes in the pattern of effective coupling of inferior olivary neurons and demonstrating that synchronous complex spike activity does not require simultaneous excitatory input to olivary cells. Finally the pattern of synchrony during motor cortical stimulation was examined. It was found that the patterns of synchrony for motor-cortex-evoked complex spike activity were similar to those of spontaneous activity, indicating an important role for electrotonic coupling in determining the response of the olivocerebellar system to afferent input. Moreover, intraolivary injections of picrotoxin increased the spatial distribution of the evoked response. In sum, the results provide evidence for the hypothesis that electrotonic coupling of inferior olivary neurons via gap junctions is the mechanism underlying complex spike synchrony and that this coupling plays an important role in determining the responses of the olivocerebellar system to synaptic input.

Preparatory activity in motor cortex reflects learning of local visuomotor skills

2003 ◽  
Vol 6 (8) ◽  
pp. 882-890 ◽  
Author(s):  
Rony Paz ◽  
Thomas Boraud ◽  
Chen Natan ◽  
Hagai Bergman ◽  
Eilon Vaadia
Keyword(s):  
Motor Cortex ◽  
Preparatory Activity ◽  
Visuomotor Skills

scholarly journals The motor cortex uses active suppression to sculpt movement

2020 ◽  
Vol 6 (34) ◽  
pp. eabb8395 ◽  
Author(s):  
Darcy M. Griffin ◽  
Peter L. Strick
Keyword(s):  
Motor Cortex ◽  
Muscle Activity ◽  
Primary Motor Cortex ◽  
Spatiotemporal Patterns ◽  
Complex Pattern ◽  
Antagonist Muscle ◽  
Active Suppression ◽  
Antagonist Muscles ◽  
Output Neurons ◽  
Command Signal

Even the simplest movements are generated by a remarkably complex pattern of muscle activity. Fast, accurate movements at a single joint are produced by a stereotyped pattern that includes a decrease in any preexisting activity in antagonist muscles. This premovement suppression is necessary to prevent the antagonist muscle from opposing movement generated by the agonist muscle. Here, we provide evidence that the primary motor cortex (M1) sends a command signal that generates this premovement suppression. Thus, output neurons in M1 sculpt complex spatiotemporal patterns of motor output not only by actively turning on muscles but also by actively turning them off.

Two classes of single-input X-cells in cat lateral geniculate nucleus. II. Retinal inputs and the generation of receptive-field properties

1987 ◽  
Vol 57 (2) ◽  
pp. 381-413 ◽  
Author(s):  
D. N. Mastronarde
Keyword(s):  
Characteristic Feature ◽  
Firing Rate ◽  
Ganglion Cell ◽  
Excitatory Input ◽  
Inhibitory Input ◽  
Excitatory Effect ◽  
Retinal Input ◽  
Cell Firing ◽  
X Cells ◽  
Y Cells

The retinal inputs to cells in the cat's lateral geniculate nucleus (LGN) were directly recorded to study the basis for the properties of two classes of LGN X-cells: Xs (single) and XL (lagged). The presence of excitatory or inhibitory input to an LGN cell from a particular simultaneously recorded ganglion cell was assessed with cross-correlograms during unstimulated activity. Because neighboring ganglion cells do not fire independently, features in a retinogeniculate correlogram can arise in two ways that must be distinguished by a direct effect of the ganglion cell on the LGN cell, or by correlated firing between that ganglion cell and some other ganglion cell that is an excitatory or inhibitory input to the LGN cell. It was possible to determine the origin of correlogram features because features indicating a retinogeniculate effect were distinctly different in timing and strength from features arising solely from correlated firing in the retina. The characteristic feature in a correlogram between an LGN cell and an excitatory retinal input was a sharp peak in LGN cell firing rate at the appropriate latency after the firing of the ganglion cell. The characteristic feature for an inhibitory input was a dip in LGN cell firing rate after the firing of the ganglion cell. Typically, this dip lasted 10-40 ms and was followed by a prolonged enhancement in LGN cell firing rate, which may reflect a postinhibitory rebound. XS-cells had a single retinal X input whose excitatory effect caused most of the LGN cell's spikes during stimulated and unstimulated activity. There was no conclusive evidence that any XS-cell received excitatory retinal input from either Y-cells or other X-cells of the same center sign. There was usually evidence for inhibition of XS-cells by retinal X-cells of opposite center sign with receptive fields highly overlapping that of the XS-cell, but rarely evidence for inhibition by Y-cells. XL-cells also had only a single excitatory input, but this X input had a relatively weak effect that caused only a minority of the LGN cell's spikes, typically 17% during maintained activity and 29% during visual stimulation. The input's excitatory effect was immediately followed by strong inhibition of the XL-cell. XL-cells were also inhibited by retinal X-cells of the same center sign that were adjacent (nearest neighbors) to the excitatory input. The strength and latency of both of these inhibitory effects indicate that the inhibition was disynaptic.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Low-Dimensional and Monotonic Preparatory Activity in Mouse Anterior Lateral Motor Cortex

2018 ◽  
Vol 38 (17) ◽  
pp. 4163-4185 ◽  
Author(s):  
Hidehiko K. Inagaki ◽  
Miho Inagaki ◽  
Sandro Romani ◽  
Karel Svoboda
Keyword(s):  
Motor Cortex ◽  
Preparatory Activity ◽  
Low Dimensional

scholarly journals Simultaneous Preparation of Multiple Potential Movements: Opposing Effects of Spatial Proximity Mediated by Premotor and Parietal Cortex

2009 ◽  
Vol 102 (4) ◽  
pp. 2084-2095 ◽  
Author(s):  
Peter Praamstra ◽  
Dimitrios Kourtis ◽  
Kianoush Nazarpour
Keyword(s):  
Motor Cortex ◽  
Distributed Control ◽  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Delay Period ◽  
Spatial Proximity ◽  
Frontoparietal Network ◽  
Neurophysiological Studies ◽  
Preparatory Activity ◽  
Posterior Parietal

Neurophysiological studies in monkey have suggested that premotor and motor cortex may prepare for multiple movements simultaneously, sustained by cooperative and competitive interactions within and between the neural populations encoding different actions. Here, we investigate whether competition between alternative movement directions, manipulated in terms of number and spatial angle, is reflected in electroencephalographic (EEG) measures of (pre)motor cortical activity in humans. EEG was recorded during performance of a center-out pointing task in which response signals were preceded by cues providing prior information in the form of arrows pointing to one or more possible movement targets. Delay-period activity in (pre)motor cortex was modulated in the predicted manner by the number of possible movement directions and by the angle separating them. Response latencies, however, were determined not only by the amplitude of movement-preparatory activity, but also by differences in the duration of stimulus evaluation against the visuospatial memory of the cue, reflected in EEG potentials originating from posterior parietal cortex (PPC). Specifically, the spatial proximity of possible movement targets was processed differently by (pre)motor and posterior parietal cortex. Spatial proximity enhanced the amplitude of (pre)motor cortex preparatory activity during the delay period but delayed evaluation of the response signal in the PPC, thus producing opposite effects on response latency. The latter finding supports distributed control of movement decisions in the frontoparietal network, revealing a feature of distributed control that is of potential significance for the understanding of distracter effects in reaching and pointing.

scholarly journals Disruption of cortical dopaminergic modulation impairs preparatory activity and delays licking initiation

2018 ◽  
Author(s):  
Ke Chen ◽  
Roberto Vincis ◽  
Alfredo Fontanini
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Motor Cortex ◽  
Neural Activity ◽  
Cortical Activity ◽  
Motor Deficits ◽  
Receptor Modulation ◽  
Dopaminergic Modulation ◽  
Preparatory Activity ◽  
Motor Cortical

ABSTRACTDysfunction of motor cortices is thought to contribute to motor disorders such as Parkinson’s disease (PD). However, little is known on the link between cortical dopaminergic loss, abnormalities in motor cortex neural activity and motor deficits. We address the role of dopamine in modulating motor cortical activity by focusing on the anterior lateral motor cortex (ALM) of mice performing a cued-licking task. We first demonstrate licking deficits and concurrent alterations of spiking activity in ALM of mice with unilateral depletion of dopaminergic neurons (i.e., mice injected with 6-OHDA into the medial forebrain bundle). Hemi-lesioned mice displayed delayed licking initiation, shorter duration of licking bouts, and lateral deviation of tongue protrusions. In parallel with these motor deficits, we observed a reduction in the prevalence of cue responsive neurons and altered preparatory activity. Acute and local blockade of D1 receptors in ALM recapitulated some of the key behavioral and neural deficits observed in hemi-lesioned mice. Altogether, our data show a direct relationship between cortical D1 receptor modulation, cue-evoked and preparatory activity in ALM, and licking initiation.SIGNIFICANCE STATEMENTThe link between dopaminergic signaling, motor cortical activity and motor deficits is not fully understood. This manuscript describes alterations in neural activity of the anterior lateral motor cortex (ALM) that correlate with licking deficits in mice with unilateral dopamine depletion or with intra-ALM infusion of dopamine antagonist. The findings emphasize the importance of cortical dopaminergic modulation in motor initiation. These results will appeal not only to researchers interested in cortical control of licking, but also to a broader audience interested in motor control and dopaminergic modulation in physiological and pathological conditions. Specifically, our data suggest that dopamine deficiency in motor cortex could play a role in the pathogenesis of the motor symptoms of Parkinson’s disease.

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