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

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.

Download Full-text

Texture coarseness responsive neurons and their mapping in layer 2–3 of the rat barrel cortex in vivo

eLife ◽

10.7554/elife.03405 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 25

Author(s):

Liora Garion ◽

Uri Dubin ◽

Yoav Rubin ◽

Mohamed Khateb ◽

Yitzhak Schiller ◽

...

Keyword(s):

Calcium Imaging ◽

Barrel Cortex ◽

Fundamental Function ◽

Tactile Information ◽

Hierarchical Processing ◽

Two Photon ◽

Columnar Organization ◽

Layer 2 ◽

Single Unit Recordings

Texture discrimination is a fundamental function of somatosensory systems, yet the manner by which texture is coded and spatially represented in the barrel cortex are largely unknown. Using in vivo two-photon calcium imaging in the rat barrel cortex during artificial whisking against different surface coarseness or controlled passive whisker vibrations simulating different coarseness, we show that layer 2–3 neurons within barrel boundaries differentially respond to specific texture coarsenesses, while only a minority of neurons responded monotonically with increased or decreased surface coarseness. Neurons with similar preferred texture coarseness were spatially clustered. Multi-contact single unit recordings showed a vertical columnar organization of texture coarseness preference in layer 2–3. These findings indicate that layer 2–3 neurons perform high hierarchical processing of tactile information, with surface coarseness embodied by distinct neuronal subpopulations that are spatially mapped onto the barrel cortex.

Download Full-text

Relative Changes in Cerebral Blood Flow and Neuronal Activity in Local Microdomains during Generalized Seizures

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/01.wcb.0000131669.02027.3e ◽

2004 ◽

Vol 24 (9) ◽

pp. 1057-1068 ◽

Cited By ~ 51

Author(s):

Hrachya Nersesyan ◽

Peter Herman ◽

Ersan Erdogan ◽

Fahmeed Hyder ◽

Hal Blumenfeld

Keyword(s):

Visual Cortex ◽

Somatosensory Cortex ◽

Neuronal Activity ◽

Barrel Cortex ◽

Similar Distribution ◽

Somatosensory Stimulation ◽

Doppler Flowmetry ◽

Absence Seizures ◽

Generalized Seizures ◽

Whisker Stimulation

There is broad agreement that generalized tonic–clonic seizures (GTCS) and normal somatosensory stimulation are associated with increases in regional CBF. However, the data regarding CBF changes during absence seizures are controversial. Electrophysiologic studies in WAG/Rij rats, an established animal model of absence seizures, have shown spike-wave discharges (SWD) that are largest in the perioral somatosensory cortex while sparing the visual cortex. Recent functional magnetic resonance imaging (fMRI) studies in the same model have also shown localized increases in fMRI signals in the perioral somatosensory cortex during SWD. Because fMRI signals are only indirectly related to neuronal activity, the authors directly measured CBF and neuronal activity from specific microdomains of the WAG/Rij cortex using a specially designed probe combining laser-Doppler flowmetry and extracellular microelectrode recordings under fentanyl/haloperidol anesthesia. Using this approach, parallel increases in neuronal activity and CBF were observed during SWD in the whisker somatosensory (barrel) cortex, whereas the visual cortex showed no significant changes. For comparison, these measurements were repeated during somatosensory (whisker) stimulation, and bicuculline-induced GTCS in the same animals. Interestingly, whisker stimulation increased neuronal activity and CBF in the barrel cortex more than during SWD. During GTCS, much larger increases that included both the somatosensory and visual cortex were observed. Thus, SWD in this model produce parallel localized increases in neuronal activity and CBF with similar distribution to somatosensory stimulation, whereas GTCS produce larger and more widespread changes. The normal response to somatosensory stimulation appears to be poised between two abnormal responses produced by two physiologically different types of seizures.

Download Full-text

The Timing of Sensory-Guided Behavioral Response is Represented in the Mouse Primary Somatosensory Cortex

Cerebral Cortex ◽

10.1093/cercor/bhy169 ◽

2018 ◽

Vol 29 (7) ◽

pp. 3034-3047

Author(s):

Jérémy Camon ◽

Sandrine Hugues ◽

Melissa A Erlandson ◽

David Robbe ◽

Sabria Lagoun ◽

...

Keyword(s):

Somatosensory Cortex ◽

Behavioral Response ◽

Barrel Cortex ◽

Ex Vivo ◽

Primary Somatosensory Cortex ◽

Cortical Columns ◽

Reward Delivery ◽

Wide Range ◽

Layer 2 ◽

Layer 4

Abstract Whisker-guided decision making in mice is thought to critically depend on information processing occurring in the primary somatosensory cortex. However, it is not clear if neuronal activity in this “early” sensory region contains information about the timing and speed of motor response. To address this question we designed a new task in which freely moving mice learned to associate a whisker stimulus to reward delivery. The task was tailored in such a way that a wide range of delays between whisker stimulation and reward collection were observed due to differences of motivation and perception. After training, mice were anesthetized and neuronal responses evoked by stimulating trained and untrained whiskers were recorded across several cortical columns of barrel cortex. We found a strong correlation between the delay of the mouse behavioral response and the timing of multiunit activity evoked by the trained whisker, outside its principal cortical column, in layers 4 and 5A but not in layer 2/3. Circuit mapping ex vivo revealed this effect was associated with a weakening of layer 4 to layer 2/3 projection. We conclude that the processes controlling the propagation of key sensory inputs to naive cortical columns and the timing of sensory-guided action are linked.

Download Full-text

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

10.1101/588129 ◽

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.

Download Full-text

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

Nature Communications ◽

10.1038/s41467-019-12670-z ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 6

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.

Download Full-text

Sensory stimulus evoked responses in layer 2/3 pyramidal neurons of the hind paw-related mouse primary somatosensory cortex

10.1101/2020.08.30.274308 ◽

2020 ◽

Author(s):

Guillaume Bony ◽

Arjun A Bhaskaran ◽

Katy Le Corf ◽

Andreas Frick

Keyword(s):

Information Processing ◽

Somatosensory Cortex ◽

Pyramidal Neurons ◽

Barrel Cortex ◽

Sensory Information ◽

Primary Somatosensory Cortex ◽

List Type ◽

Evoked Responses ◽

Spontaneous Firing ◽

Layer 2

ABSTRACTThe mouse primary somatosensory cortex (S1) processes tactile sensory information and is the largest neocortex area emphasizing the importance of this sensory modality for rodent behavior. Most of our knowledge regarding information processing in S1 stems from studies of the whisker-related barrel cortex (S1–BC), yet the processing of tactile inputs from the hind-paws is poorly understood. We used in vivo whole-cell patch-clamp recordings from layer (L) 2/3 pyramidal neurons (PNs) of the S1 hind-paw (S1-HP) region of anaesthetized wild type (WT) mice to investigate their evoked sub- and supra-threshold activity, intrinsic properties, and spontaneous activity. Approximately 45% of these L2/3 PNs responded to brief contralateral HP stimulation in a subthreshold manner, ~5% fired action potentials, and ~50% of L2/3 PNs did not respond at all. The evoked subthreshold responses had long onset- (~23 ms) and peak-latencies (~61 ms). The majority (86%) of these L2/3 PNs responded to prolonged (stance-like) HP stimulation with both on- and off-responses. HP stimulation responsive L2/3 PNs had a greater intrinsic excitability compared to non-responsive ones, possibly reflecting differences in their physiological role. Similar to S1-BC, L2/3 PNs displayed up- and down-states, and low spontaneous firing rates (~0.1 Hz). Our findings support a sparse coding scheme of operation for S1–HP L2/3 PNs and highlight both differences and similarities with L2/3 PNs from other somatosensory cortex areas.KEY POINTSResponses of layer (L) 2/3 pyramidal neurons (PNs) of the primary somatosensory hind-paw cortex (S1-HP) to contralateral hind-paw stimulation reveal both differences and similarities compared to those of somatosensory neurons responding to other tactile (e.g. whiskers, forepaw, tongue) modalities.Similar to whisker-related barrel cortex (S1-BC) and forepaw cortex (S1-FP) S1-HP L2/3 PNs show a low spontaneous firing rate and a sparse action potential coding of evoked activity.In contrast to S1-BC, brief hind-paw stimulus evoked responses display a long latency in S1-HP neurons consistent with their different functional role.The great majority of L 2/3 PNs respond to prolonged hind-paw stimulation with both on- and off-responses.These results help us to better understand sensory information processing within layer 2/3 of the neocortex and the regional differences related to various tactile modalities.

Download Full-text