scholarly journals Context-dependent limb movement encoding in neuronal populations of motor cortex

2019 ◽  
Author(s):  
Wolfgang Omlor ◽  
Pia Sipilä ◽  
Anna-Sophia Wahl ◽  
Henry Lütcke ◽  
Balazs Laurenczy ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Calcium Imaging ◽  
Population Coding ◽  
Context Dependence ◽  
Joint Movement ◽  
Joint Processing ◽  
Neuronal Populations ◽  
Layer 2 ◽  
Network Encoding

Neuronal networks of the mammalian motor cortex (M1) are important for dexterous control of limb joints. Yet it remains unclear how encoding of joint movement in M1 networks depends on varying environmental contexts. Using calcium imaging we measured neuronal activity in layer 2/3 of the mouse M1 forelimb region while mice grasped either regularly or irregularly spaced ladder rungs during locomotion. We found that population coding of forelimb joint movements is sparse and varies according to the flexibility demanded from them in the regular and irregular context, even for equivalent grasping actions across conditions. This context-dependence of M1 network encoding emerged during learning of the locomotion task, fostered more precise grasping actions, but broke apart upon silencing of projections from secondary motor cortex (M2). These findings suggest that M2 reconfigures M1 neuronal circuits to adapt joint processing to the flexibility demands in specific familiar contexts, thereby increasing the accuracy of motor output.

scholarly journals Context-dependent limb movement encoding in neuronal populations of motor cortex

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Wolfgang Omlor ◽  
Anna-Sophia Wahl ◽  
Pia Sipilä ◽  
Henry Lütcke ◽  
Balazs Laurenczy ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Calcium Imaging ◽  
Limb Movement ◽  
Population Coding ◽  
Motor Output ◽  
Context Dependence ◽  
Joint Movement ◽  
Neuronal Populations ◽  
Layer 2

Abstract Neuronal networks of the mammalian motor cortex (M1) are important for dexterous control of limb joints. Yet it remains unclear how encoding of joint movement in M1 depends on varying environmental contexts. Using calcium imaging we measured neuronal activity in layer 2/3 of the M1 forelimb region while mice grasped regularly or irregularly spaced ladder rungs during locomotion. We found that population coding of forelimb joint movements is sparse and varies according to the flexibility demanded from individual joints in the regular and irregular context, even for equivalent grasping actions across conditions. This context-dependence of M1 encoding emerged during task learning, fostering higher precision of grasping actions, but broke apart upon silencing of projections from secondary motor cortex (M2). These findings suggest that M1 exploits information from M2 to adapt encoding of joint movements to the flexibility demands of distinct familiar contexts, thereby increasing the accuracy of motor output.

scholarly journals Layer-specific integration of locomotion and concurrent wall touching in mouse barrel cortex

2018 ◽  
Author(s):  
Asli Ayaz ◽  
Andreas Stäuble ◽  
Aman B Saleem ◽  
Fritjof Helmchen
Keyword(s):  
Virtual Reality ◽  
Somatosensory Cortex ◽  
Neuronal Activity ◽  
Calcium Imaging ◽  
Barrel Cortex ◽  
Sustained Activity ◽  
Tactile Stimuli ◽  
Layer 2 ◽  
Self Motion ◽  
Increased Activity

During navigation rodents continually sample the environment with their whiskers. How locomotion modulates neuronal activity in somatosensory cortex and how self-motion is integrated with whisker touch remains unclear. Here, we used calcium imaging in mice running in a tactile virtual reality to investigate modulation of neurons in layer 2/3 (L2/3) and L5 of barrel cortex. About a third of neurons in both layers increased activity during running and concomitant whisking, in the absence of touch. Fewer neurons were modulated by whisking alone (<10%). Whereas L5 neurons responded transiently to wall-touching during running, L2/3 neurons showed sustained activity after touch onset. Consistently, neurons encoding running-with-touch were more abundant in L2/3 compared to L5. Few neurons across layers were also sensitive to abrupt perturbations of tactile flow. We propose that L5 neurons mainly report changes in touch conditions whereas L2/3 neurons continually monitor ongoing tactile stimuli during running.

scholarly journals Stability of motor cortex network states during learning-associated neural reorganizations

2020 ◽  
Vol 124 (5) ◽  
pp. 1327-1342
Author(s):  
Zhengyu Ma ◽  
Haixin Liu ◽  
Takaki Komiyama ◽  
Ralf Wessel
Keyword(s):  
Motor Cortex ◽  
Motor Learning ◽  
Neural Activity ◽  
Calcium Imaging ◽  
Premotor Cortex ◽  
Two Photon ◽  
Layer 2 ◽  
Network States ◽  
The Stability

The neural activity reorganizes throughout motor learning, but how this reorganization impacts the stability of network states is unclear. We used two-photon calcium imaging to investigate how the network states in layer 2/3 and layer 5 of forelimb motor and premotor cortex are modulated by motor learning. We show that motor cortex network states are layer-specific and constant regarding criticality during neural activity reorganization, and suggests that layer-specific constraints could be motivated by different functions.

scholarly journals Population Coding of Self-Motion: Applying Bayesian Analysis to a Population of Visual Interneurons in the Fly

2005 ◽  
Vol 94 (3) ◽  
pp. 2182-2194 ◽  
Author(s):  
Katja Karmeier ◽  
Holger G. Krapp ◽  
Martin Egelhaaf
Keyword(s):  
Bayesian Analysis ◽  
Rotation Axis ◽  
Sensory Information ◽  
Population Coding ◽  
Calliphora Vicina ◽  
Integration Time ◽  
Noise Correlation ◽  
Neuronal Populations ◽  
Response Onset ◽  
Self Motion

Coding of sensory information often involves the activity of neuronal populations. We demonstrate how the accuracy of a population code depends on integration time, the size of the population, and noise correlation between the participating neurons. The population we study consists of 10 identified visual interneurons in the blowfly Calliphora vicina involved in optic flow processing. These neurons are assumed to encode the animal's head or body rotations around horizontal axes by means of graded potential changes. From electrophysiological experiments we obtain parameters for modeling the neurons' responses. From applying a Bayesian analysis on the modeled population response we draw three major conclusions. First, integration of neuronal activities over a time period of only 5 ms after response onset is sufficient to decode accurately the rotation axis. Second, noise correlation between neurons has only little impact on the population's performance. And third, although a population of only two neurons would be sufficient to encode any horizontal rotation axis, the population of 10 vertical system neurons is advantageous if the available integration time is short. For the fly, short integration times to decode neuronal responses are important when controlling rapid flight maneuvers.

scholarly journals Mechanisms underlying the response of mouse cortical networks to optogenetic manipulation

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Alexandre Mahrach ◽  
Guang Chen ◽  
Nuo Li ◽  
Carl van Vreeswijk ◽  
David Hansel
Keyword(s):  
Motor Cortex ◽  
Numerical Simulations ◽  
Barrel Cortex ◽  
Population Models ◽  
Gabaergic Interneurons ◽  
Paradoxical Effect ◽  
Form Complex ◽  
Recurrent Excitation ◽  
Layer 2

GABAergic interneurons can be subdivided into three subclasses: parvalbumin positive (PV), somatostatin positive (SOM) and serotonin positive neurons. With principal cells (PCs) they form complex networks. We examine PCs and PV responses in mouse anterior lateral motor cortex (ALM) and barrel cortex (S1) upon PV photostimulation in vivo. In ALM layer five and S1, the PV response is paradoxical: photoexcitation reduces their activity. This is not the case in ALM layer 2/3. We combine analytical calculations and numerical simulations to investigate how these results constrain the architecture. Two-population models cannot explain the results. Four-population networks with V1-like architecture account for the data in ALM layer 2/3 and layer 5. Our data in S1 can be explained if SOM neurons receive inputs only from PCs and PV neurons. In both four-population models, the paradoxical effect implies not too strong recurrent excitation. It is not evidence for stabilization by inhibition.

scholarly journals Cortical circuit alterations precede disease onset in Huntington’s disease mice

2018 ◽  
Author(s):  
Johanna Neuner ◽  
Elena Katharina Schulz-Trieglaff ◽  
Sara Gutiérrez-Ángel ◽  
Fabian Hosp ◽  
Matthias Mann ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Primary Motor Cortex ◽  
Disease Onset ◽  
Single Neurons ◽  
Two Photon ◽  
Layer 2 ◽  
Cortical Circuit

AbstractHuntington’s disease (HD) is a devastating hereditary movement disorder, characterized by degeneration of neurons in the striatum and cortex. Studies in human patients and mouse HD models suggest that disturbances of neuronal function in the neocortex play an important role in the disease onset and progression. However, the precise nature and time course of cortical alterations in HD have remained elusive. Here, we use chronicin vivotwo-photon calcium imaging to monitor the activity of single neurons in layer 2/3 of the primary motor cortex in awake, behaving R6/2 transgenic HD mice and wildtype littermates. R6/2 mice show age-dependent changes in neuronal activity with a clear increase in activity at the age of 8.5 weeks, preceding the onset of motor and neurological symptoms. Furthermore, quantitative proteomics demonstrate a pronounced downregulation of synaptic proteins in the cortex, and histological analyses in R6/2 mice and HD patient samples reveal reduced inputs from parvalbumin-positive interneurons onto layer 2/3 pyramidal cells. Thus, our study provides a time-resolved description as well as mechanistic details of cortical circuit dysfunction in HD.Significance statementFuntional alterations in the cortex are believed to play an important role in the pathogenesis of Huntington’s disease (HD). However, studies monitoring cortical activity in HD modelsin vivoat a single-cell resultion are still lacking. We have used chronic two-photon imaging to investigate changes in the activity of single neurons in the primary motor cortex of awake presymptomatic HD mice. We show that neuronal activity increases before the mice develop disease symptoms. Our histological analyses in mice and in human HD autopsy cases furthermore demonstrate a loss inhibitory synaptic terminals from parvalbimun-positive interneurons, revealing a potential mechanism of cortical circuit impairment in HD.

scholarly journals Fiber photometry does not reflect spiking activity in the striatum

2021 ◽  
Author(s):  
Alex A. Legaria ◽  
Julia A. Licholai ◽  
Alexxai V. Kravitz
Keyword(s):  
Neuronal Activity ◽  
Calcium Imaging ◽  
Brain Activity ◽  
Neural Population ◽  
Fluorescence Signal ◽  
Calcium Signals ◽  
Cellular Events ◽  
Neural Populations ◽  
Spiking Activity

AbstractFiber photometry recordings are commonly used as a proxy for neuronal activity, based on the assumption that increases in bulk calcium fluorescence reflect increases in spiking of the underlying neural population. However, this assumption has not been adequately tested. Here, using endoscopic calcium imaging in the striatum we report that the bulk fluorescence signal correlates weakly with somatic calcium signals, suggesting that this signal does not reflect spiking activity, but may instead reflect subthreshold changes in neuropil calcium. Consistent with this suggestion, the bulk fluorescence photometry signal correlated strongly with neuropil calcium signals extracted from these same endoscopic recordings. We further confirmed that photometry did not reflect striatal spiking activity with simultaneous in vivo extracellular electrophysiology and fiber photometry recordings in awake behaving mice. We conclude that the fiber photometry signal should not be considered a proxy for spiking activity in neural populations in the striatum.Significance statementFiber photometry is a technique for recording brain activity that has gained popularity in recent years due to it being an efficient and robust way to record the activity of genetically defined populations of neurons. However, it remains unclear what cellular events are reflected in the photometry signal. While it is often assumed that the photometry signal reflects changes in spiking of the underlying cell population, this has not been adequately tested. Here, we processed calcium imaging recordings to extract both somatic and non-somatic components of the imaging field, as well as a photometry signal from the whole field. Surprisingly, we found that the photometry signal correlated much more strongly with the non-somatic than the somatic signals. This suggests that the photometry signal most strongly reflects subthreshold changes in calcium, and not spiking. We confirmed this point with simultaneous fiber photometry and extracellular spiking recordings, again finding that photometry signals relate poorly to spiking in the striatum. Our results may change interpretations of studies that use fiber photometry as an index of spiking output of neural populations.

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