scholarly journals Modulation of artificial whisking related signals in barrel cortex

2015 ◽  
Vol 113 (5) ◽  
pp. 1287-1301 ◽  
Author(s):  
Manuel A. Castro-Alamancos ◽  
Tatiana Bezdudnaya
Keyword(s):  
Superior Colliculus ◽  
Sensory Processing ◽  
Barrel Cortex ◽  
Motor Nerve ◽  
Low Frequency ◽  
Cortical Activation ◽  
Neural Responses ◽  
Population Responses ◽  
Processing Abilities ◽  
Network States

Rats use rhythmic whisker movements, called active whisking, to sense the environment, which include whisker protractions followed by retractions at various frequencies. Using a proxy of active whisking in anesthetized rats, called artificial whisking, which is induced by electrically stimulating the facial motor nerve, we characterized the neural responses evoked in the barrel cortex by whisking in air (without contact) and on a surface (with contact). Neural responses were compared between distinct network states consisting of cortical deactivation (synchronized slow oscillations) and activation (desynchronized state) produced by neuromodulation (cholinergic or noradrenergic stimulation in neocortex or thalamus). Here we show that population responses in the barrel cortex consist of a robust signal driven by the onset of the whisker protraction followed by a whisking retraction signal that emerges during low frequency whisking on a surface. The whisking movement onset signal is suppressed by increasing whisking frequency, is controlled by cortical synaptic inhibition, is suppressed during cortical activation states, is little affected by whisking on a surface, and is ubiquitous in ventroposterior medial (VPM) thalamus, barrel cortex, and superior colliculus. The whisking retraction signal codes the duration of the preceding whisker protraction, is present in thalamocortical networks but not in superior colliculus, and is robust during cortical activation; a state associated with natural exploratory whisking. The expression of different whisking signals in forebrain and midbrain may define the sensory processing abilities of those sensorimotor circuits. Whisking related signals in the barrel cortex are controlled by network states that are set by neuromodulators.

scholarly journals Effects of cortical activation on sensory responses in barrel cortex

2011 ◽  
Vol 105 (4) ◽  
pp. 1495-1505 ◽  
Author(s):  
Akio Hirata ◽  
Manuel A. Castro-Alamancos
Keyword(s):  
Barrel Cortex ◽  
Low Frequency ◽  
Cortical Activation ◽  
Network Activity ◽  
Cortical Cells ◽  
Cholinergic Agonists ◽  
Potential Fluctuations ◽  
Activated State ◽  
Sensory Responses ◽  
Membrane Potential Fluctuations

Neocortex network activity changes from a deactivated state during quiescence to an activated state during arousal and vigilance. In urethane-anesthetized rats, cortical activation is readily produced by either stimulating the brainstem reticular formation or by application of cholinergic agonists into the thalamus. We studied the effects of cortical activation on spontaneous activity and sensory responses in the barrel cortex. Cortical activation leads to a suppression of low-frequency sensory responses and to a reduction in their variability due to the abolishment of up and down membrane potential fluctuations in cortical cells. Overall, sensory responses become sharper and more reliable during cortical activation.

scholarly journals Superior colliculus cells sensitive to active touch and texture during whisking

2011 ◽  
Vol 106 (1) ◽  
pp. 332-346 ◽  
Author(s):  
Tatiana Bezdudnaya ◽  
Manuel A. Castro-Alamancos
Keyword(s):  
Neural Network ◽  
Superior Colliculus ◽  
Single Unit ◽  
Barrel Cortex ◽  
Motor Nerve ◽  
Field Potential ◽  
Active Touch ◽  
Short Latency ◽  
Texture Discrimination ◽  
Passive Touch

Rats sense the environment through rhythmic vibrissa protractions, called active whisking, which can be simulated in anesthetized rats by electrically stimulating the facial motor nerve. Using this method, we investigated barrel cortex field potential and superior colliculus single-unit responses during passive touch, whisking movement, active touch, and texture discrimination. Similar to passive touch, whisking movement is signaled during the onset of the whisker protraction by short-latency responses in barrel cortex that drive corticotectal responses in superior colliculus, and all these responses show robust adaptation with increases in whisking frequency. Active touch and texture are signaled by longer latency responses, first in superior colliculus during the rising phase of the protraction, likely driven by trigeminotectal inputs, and later in barrel cortex by the falling phase of the protraction. Thus, superior colliculus is part of a broader vibrissa neural network that can decode whisking movement, active touch, and texture.

scholarly journals Changes in Sensorimotor Cortical Activation in Children Using Prostheses and Prosthetic Simulators

2021 ◽  
Vol 11 (8) ◽  
pp. 991
Author(s):  
Christopher Copeland ◽  
Mukul Mukherjee ◽  
Yingying Wang ◽  
Kaitlin Fraser ◽  
Jorge M. Zuniga
Keyword(s):  
Near Infrared ◽  
Primary Motor Cortex ◽  
Tactile Feedback ◽  
Cortical Activation ◽  
Typically Developing ◽  
Neural Responses ◽  
Motor Tasks ◽  
Functional Near Infrared Spectroscopy ◽  
Limb Reduction ◽  
Motor Dexterity

This study aimed to examine the neural responses of children using prostheses and prosthetic simulators to better elucidate the emulation abilities of the simulators. We utilized functional near-infrared spectroscopy (fNIRS) to evaluate the neural response in five children with a congenital upper limb reduction (ULR) using a body-powered prosthesis to complete a 60 s gross motor dexterity task. The ULR group was matched with five typically developing children (TD) using their non-preferred hand and a prosthetic simulator on the same hand. The ULR group had lower activation within the primary motor cortex (M1) and supplementary motor area (SMA) compared to the TD group, but nonsignificant differences in the primary somatosensory area (S1). Compared to using their non-preferred hand, the TD group exhibited significantly higher action in S1 when using the simulator, but nonsignificant differences in M1 and SMA. The non-significant differences in S1 activation between groups and the increased activation evoked by the simulator’s use may suggest rapid changes in feedback prioritization during tool use. We suggest that prosthetic simulators may elicit increased reliance on proprioceptive and tactile feedback during motor tasks. This knowledge may help to develop future prosthesis rehabilitative training or the improvement of tool-based skills.

scholarly journals Frequency Sensitivity of Neural Responses to English Verb Argument Structure Violations

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Jona Sassenhagen ◽  
Ryan Blything ◽  
Elena V. M. Lieven ◽  
Ben Ambridge
Keyword(s):  
Statistical Learning ◽  
High Frequency ◽  
Argument Structure ◽  
Low Frequency ◽  
Event Related Potentials ◽  
Neural Responses ◽  
Online Processing ◽  
Verb Argument Structure ◽  
Related Potentials ◽  
Intransitive Verbs

How are verb-argument structure preferences acquired? Children typically receive very little negative evidence, raising the question of how they come to understand the restrictions on grammatical constructions. Statistical learning theories propose stochastic patterns in the input contain sufficient clues. For example, if a verb is very common, but never observed in transitive constructions, this would indicate that transitive usage of that verb is illegal. Ambridge et al. (2008) have shown that in offline grammaticality judgements of intransitive verbs used in transitive constructions, low-frequency verbs elicit higher acceptability ratings than high-frequency verbs, as predicted if relative frequency is a cue during statistical learning. Here, we investigate if the same pattern also emerges in on-line processing of English sentences. EEG was recorded while healthy adults listened to sentences featuring transitive uses of semantically matched verb pairs of differing frequencies. We replicate the finding of higher acceptabilities of transitive uses of low- vs. high-frequency intransitive verbs. Event-Related Potentials indicate a similar result: early electrophysiological signals distinguish between misuse of high- vs low-frequency verbs. This indicates online processing shows a similar sensitivity to frequency as off-line judgements, consistent with a parser that reflects an original acquisition of grammatical constructions via statistical cues. However, the nature of the observed neural responses was not of the expected, or an easily interpretable, form, motivating further work into neural correlates of online processing of syntactic constructions.

scholarly journals Neurovascular coupling during optogenetic functional activation: Local and remote stimulus-response characteristics, and uncoupling by spreading depression

2019 ◽  
Vol 40 (4) ◽  
pp. 808-822 ◽  
Author(s):  
Maximilian Böhm ◽  
David Y Chung ◽  
Carlos A Gómez ◽  
Tao Qin ◽  
Tsubasa Takizawa ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Spreading Depression ◽  
Barrel Cortex ◽  
Disease Process ◽  
Neurovascular Coupling ◽  
Laser Speckle ◽  
Cortical Activation ◽  
Somatosensory Stimulation ◽  
Response Characteristics ◽  
Electrophysiological Activity

Neurovascular coupling is a fundamental response that links activity to perfusion. Traditional paradigms of neurovascular coupling utilize somatosensory stimulation to activate the primary sensory cortex through subcortical relays. Therefore, examination of neurovascular coupling in disease models can be confounded if the disease process affects these multisynaptic pathways. Optogenetic stimulation is an alternative to directly activate neurons, bypassing the subcortical relays. We employed minimally invasive optogenetic cortical activation through intact skull in Thy1-channelrhodopsin-2 transgenic mice, examined the blood flow changes using laser speckle imaging, and related these to evoked electrophysiological activity. Our data show that optogenetic activation of barrel cortex triggers intensity- and frequency-dependent hyperemia both locally within the barrel cortex (>50% CBF increase), and remotely within the ipsilateral motor cortex (>30% CBF increase). Intriguingly, activation of the barrel cortex causes a small (∼10%) but reproducible hypoperfusion within the contralateral barrel cortex, electrophysiologically linked to transhemispheric inhibition. Cortical spreading depression, known to cause neurovascular uncoupling, diminishes optogenetic hyperemia by more than 50% for up to an hour despite rapid recovery of evoked electrophysiological activity, recapitulating a unique feature of physiological neurovascular coupling. Altogether, these data establish a minimally invasive paradigm to investigate neurovascular coupling for longitudinal characterization of cerebrovascular pathologies.

Effects of low-frequency stimulation of the superior colliculus on spontaneous and visually guided saccades

1993 ◽  
Vol 69 (3) ◽  
pp. 953-964 ◽  
Author(s):  
P. W. Glimcher ◽  
D. L. Sparks
Keyword(s):  
Superior Colliculus ◽  
Time Course ◽  
Low Frequency ◽  
Arbitrary Point ◽  
Visually Guided ◽  
Spontaneous Movements ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Current ◽  
Stimulation Of

1. The first experiment of this study determined the effects of low-frequency stimulation of the monkey superior colliculus on spontaneous saccades in the dark. Stimulation trains, subthreshold for eliciting short-latency fixed-vector saccades, were highly effective at biasing the metrics (direction and amplitude) of spontaneous movements. During low-frequency stimulation, the distribution of saccade metrics was biased toward the direction and amplitude of movements induced by suprathreshold stimulation of the same collicular location. 2. Low-frequency stimulation biased the distribution of saccade metrics but did not initiate movements. The distribution of intervals between stimulation onset and the onset of the next saccade did not differ significantly from the distribution of intervals between an arbitrary point in time and the onset of the next saccade under unstimulated conditions. 3. Results of our second experiment indicate that low-frequency stimulation also influenced the metrics of visually guided saccades. The magnitude of the stimulation-induced bias increased as stimulation current or frequency was increased. 4. The time course of these effects was analyzed by terminating stimulation immediately before, during, or after visually guided saccades. Stimulation trains terminated at the onset of a movement were as effective as stimulation trains that continued throughout the movement. No effects were observed if stimulation ended 40–60 ms before the movement began. 5. These results show that low-frequency collicular stimulation can influence the direction and amplitude of spontaneous or visually guided saccades without initiating a movement. These data are compatible with the hypothesis that the collicular activity responsible for specifying the horizontal and vertical amplitude of a saccade differs from the type of collicular activity that initiates a saccade.

Auditory Imagery Modulates Frequency-specific Areas in the Human Auditory Cortex

2013 ◽  
Vol 25 (2) ◽  
pp. 175-187 ◽  
Author(s):  
Jihoon Oh ◽  
Jae Hyung Kwon ◽  
Po Song Yang ◽  
Jaeseung Jeong
Keyword(s):  
Auditory Cortex ◽  
High Frequency ◽  
Low Frequency ◽  
Primary Auditory Cortex ◽  
Auditory Imagery ◽  
Neural Responses ◽  
Top Down ◽  
Visual Areas ◽  
Control Functional ◽  
Response Area

Neural responses in early sensory areas are influenced by top–down processing. In the visual system, early visual areas have been shown to actively participate in top–down processing based on their topographical properties. Although it has been suggested that the auditory cortex is involved in top–down control, functional evidence of topographic modulation is still lacking. Here, we show that mental auditory imagery for familiar melodies induces significant activation in the frequency-responsive areas of the primary auditory cortex (PAC). This activation is related to the characteristics of the imagery: when subjects were asked to imagine high-frequency melodies, we observed increased activation in the high- versus low-frequency response area; when the subjects were asked to imagine low-frequency melodies, the opposite was observed. Furthermore, we found that A1 is more closely related to the observed frequency-related modulation than R in tonotopic subfields of the PAC. Our findings suggest that top–down processing in the auditory cortex relies on a mechanism similar to that used in the perception of external auditory stimuli, which is comparable to early visual systems.

Effects of Local Nicotinic Activation of the Superior Colliculus on Saccades in Monkeys

2005 ◽  
Vol 93 (1) ◽  
pp. 519-534 ◽  
Author(s):  
Masayuki Watanabe ◽  
Yasushi Kobayashi ◽  
Yuka Inoue ◽  
Tadashi Isa
Keyword(s):  
Superior Colliculus ◽  
Reaction Times ◽  
Low Frequency ◽  
Visually Guided ◽  
Population Activity ◽  
Affected Area ◽  
Movement Field ◽  
Neural Interactions ◽  
Restricted Region

To examine the role of competitive and cooperative neural interactions within the intermediate layer of superior colliculus (SC), we elevated the basal SC neuronal activity by locally injecting a cholinergic agonist nicotine and analyzed its effects on saccade performance. After microinjection, spontaneous saccades were directed toward the movement field of neurons at the injection site (affected area). For visually guided saccades, reaction times were decreased when targets were presented close to the affected area. However, when visual targets were presented remote from the affected area, reaction times were not increased regardless of the rostrocaudal level of the injection sites. The endpoints of visually guided saccades were biased toward the affected area when targets were presented close to the affected area. After this endpoint effect diminished, the trajectories of visually guided saccades remained modestly curved toward the affected area. Compared with the effects on endpoints, the effects on reaction times were more localized to the targets close to the affected area. These results are consistent with a model that saccades are triggered by the activities of neurons within a restricted region, and the endpoints and trajectories of the saccades are determined by the widespread population activity in the SC. However, because increased reaction times were not observed for saccades toward targets remote from the affected area, inhibitory interactions in the SC may not be strong enough to shape the spatial distribution of the low-frequency preparatory activities in the SC.

scholarly journals Dendritic spikes in apical oblique dendrites of cortical layer 5 pyramidal neurons

2020 ◽  
Author(s):  
Michael Lawrence G. Castañares ◽  
Greg J. Stuart ◽  
Vincent R. Daria
Keyword(s):  
Sensory Processing ◽  
Pyramidal Neurons ◽  
Low Frequency ◽  
Cortical Layer ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Basal Dendrites ◽  
Dendritic Spikes ◽  
Specific Computation

AbstractDendritic spikes in layer 5 pyramidal neurons (L5PNs) play a major role in cortical computation. While dendritic spikes have been studied extensively in apical and basal dendrites of L5PNs, whether oblique dendrites, which ramify in the input layers of the cortex, also generate dendritic spikes is unknown. Here we report the existence of dendritic spikes in apical oblique dendrites of L5PNs. In silico investigations indicate that oblique branch spikes are triggered by brief, low-frequency action potential (AP) trains (~40 Hz) and are characterized by a fast sodium spike followed by activation of voltage-gated calcium channels. In vitro experiments confirmed the existence of oblique branch spikes in L5PNs during brief AP trains at frequencies of around 60 Hz. Oblique branch spikes offer new insights into branch-specific computation in L5PNs and may be critical for sensory processing in the input layers of the cortex.

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