scholarly journals Active Role of Self-Sustained Neural Activity on Sensory Input Processing: A Minimal Theoretical Model

2022 ◽  
pp. 1-30
Author(s):  
Bruno A. Santos ◽  
Rogerio M. Gomes ◽  
Xabier E. Barandiaran ◽  
Phil Husbands

Abstract A growing body of work has demonstrated the importance of ongoing oscillatory neural activity in sensory processing and the generation of sensorimotor behaviors. It has been shown, for several different brain areas, that sensory-evoked neural oscillations are generated from the modulation by sensory inputs of inherent self-sustained neural activity (SSA). This letter contributes to that strand of research by introducing a methodology to investigate how much of the sensory-evoked oscillatory activity is generated by SSA and how much is generated by sensory inputs within the context of sensorimotor behavior in a computational model. We develop an abstract model consisting of a network of three Kuramoto oscillators controlling the behavior of a simulated agent performing a categorical perception task. The effects of sensory inputs and SSAs on sensory-evoked oscillations are quantified by the cross product of velocity vectors in the phase space of the network under different conditions (disconnected without input, connected without input, and connected with input). We found that while the agent is carrying out the task, sensory-evoked activity is predominantly generated by SSA (93.10%) with much less influence from sensory inputs (6.90%). Furthermore, the influence of sensory inputs can be reduced by 10.4% (from 6.90% to 6.18%) with a decay in the agent's performance of only 2%. A dynamical analysis shows how sensory-evoked oscillations are generated from a dynamic coupling between the level of sensitivity of the network and the intensity of the input signals. This work may suggest interesting directions for neurophysiological experiments investigating how self-sustained neural activity influences sensory input processing, and ultimately affects behavior.

2015 ◽  
Vol 113 (7) ◽  
pp. 2824-2839 ◽  
Author(s):  
Tuan V. Bui ◽  
Robert M. Brownstone

Sensory inputs from muscle, cutaneous, and joint afferents project to the spinal cord, where they are able to affect ongoing locomotor activity. Activation of sensory input can initiate or prolong bouts of locomotor activity depending on the identity of the sensory afferent activated and the timing of the activation within the locomotor cycle. However, the mechanisms by which afferent activity modifies locomotor rhythm and the distribution of sensory afferents to the spinal locomotor networks have not been determined. Considering the many sources of sensory inputs to the spinal cord, determining this distribution would provide insights into how sensory inputs are integrated to adjust ongoing locomotor activity. We asked whether a sparsely distributed set of sensory inputs could modify ongoing locomotor activity. To address this question, several computational models of locomotor central pattern generators (CPGs) that were mechanistically diverse and generated locomotor-like rhythmic activity were developed. We show that sensory inputs restricted to a small subset of the network neurons can perturb locomotor activity in the same manner as seen experimentally. Furthermore, we show that an architecture with sparse sensory input improves the capacity to gate sensory information by selectively modulating sensory channels. These data demonstrate that sensory input to rhythm-generating networks need not be extensively distributed.


1998 ◽  
Vol 80 (3) ◽  
pp. 1598-1604 ◽  
Author(s):  
Mitra J. Hartmann ◽  
James M. Bower

Hartmann, Mitra J. and James M. Bower. Oscillatory activity in the cerebellar hemispheres of unrestrained rats. J. Neurophysiol. 80: 1598–1604, 1998. We recorded multiunit neural activity in the granule cell layer of cerebellar folium Crus IIa in unrestrained rats. Seven- to 8-Hz oscillatory activity was seen during behavioral states in which the animal was immobile; any movement the animal made coincided with termination of the oscillations. However, nearly one-third of oscillatory episodes appeared to cease spontaneously, in the absence of any observable sensory input or movement. Oscillations were synchronized both within and between cerebellar hemispheres, demonstrating precise temporal coordination among multiple, bilateral levels of the somatosensory system. We interpret these data in the context of similar oscillations observed in other brain structures and suggest that the oscillations are an underlying dynamic property of the entire somatosensory network.


2021 ◽  
Author(s):  
Anton Filipchuk ◽  
Alain Destexhe ◽  
Brice Bathellier

AbstractNeural activity in sensory cortex combines stimulus responses and ongoing activity, but it remains unclear whether they reflect the same underlying dynamics or separate processes. Here we show that during wakefulness, the neuronal assemblies evoked by sounds in the auditory cortex and thalamus are specific to the stimulus and distinct from the assemblies observed in ongoing activity. In contrast, during anesthesia, evoked assemblies are indistinguishable from ongoing assemblies in cortex, while they remain distinct in the thalamus. A strong remapping of sensory responses accompanies this dynamical state change produced by anesthesia. Together, these results show that the awake cortex engages dedicated neuronal assemblies in response to sensory inputs, which we suggest is a network correlate of sensory perception.One-Sentence SummarySensory responses in the awake cortex engage specific neuronal assemblies that disappear under anesthesia.


2020 ◽  
Author(s):  
Mathew L Rynes ◽  
Daniel Surinach ◽  
Samantha Linn ◽  
Michael Laroque ◽  
Vijay Rajendran ◽  
...  

ABSTRACTThe advent of genetically encoded calcium indicators, along with surgical preparations such as thinned skulls or refractive index matched skulls, have enabled mesoscale cortical activity imaging in head-fixed mice. Such imaging studies have revealed complex patterns of coordinated activity across the cortex during spontaneous behaviors, goal-directed behavior, locomotion, motor learning, and perceptual decision making. However, neural activity during unrestrained behavior significantly differs from neural activity in head-fixed animals. Whole-cortex imaging in freely behaving mice will enable the study of neural activity in a larger, more complex repertoire of behaviors not possible in head-fixed animals. Here we present the “Mesoscope,” a wide-field miniaturized, head-mounted fluorescence microscope compatible with transparent polymer skulls recently developed by our group. With a field of view of 8 mm x 10 mm and weighing less than 4 g, the Mesoscope can image most of the mouse dorsal cortex with resolution ranging from 39 to 56 µm. Stroboscopic illumination with blue and green LEDs allows for the measurement of both fluorescence changes due to calcium activity and reflectance signals to capture hemodynamic changes. We have used the Mesoscope to successfully record mesoscale calcium activity across the dorsal cortex during sensory-evoked stimuli, open field behaviors, and social interactions. Finally, combining the mesoscale imaging with electrophysiology enabled us to measure dynamics in extracellular glutamate release in the cortex during the transition from wakefulness to natural sleep.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Carmelo Bellardita ◽  
Vittorio Caggiano ◽  
Roberto Leiras ◽  
Vanessa Caldeira ◽  
Andrea Fuchs ◽  
...  

Spasms after spinal cord injury (SCI) are debilitating involuntary muscle contractions that have been associated with increased motor neuron excitability and decreased inhibition. However, whether spasms involve activation of premotor spinal excitatory neuronal circuits is unknown. Here we use mouse genetics, electrophysiology, imaging and optogenetics to directly target major classes of spinal interneurons as well as motor neurons during spasms in a mouse model of chronic SCI. We find that assemblies of excitatory spinal interneurons are recruited by sensory input into functional circuits to generate persistent neural activity, which interacts with both the graded expression of plateau potentials in motor neurons to generate spasms, and inhibitory interneurons to curtail them. Our study reveals hitherto unrecognized neuronal mechanisms for the generation of persistent neural activity under pathophysiological conditions, opening up new targets for treatment of muscle spasms after SCI.


Author(s):  
Silvia-Raluca Matei ◽  
Damian Mircea Totolan ◽  
Claudia Salceanu

Occupational therapy focuses on children's sensory processing and modulation. This chapter approaches specific interventions on children with ASD from several perspectives. OT is based on sensory integrative approach when working with children with ASD: helping parents understand their child's behavior, helping children organize responses to sensory input. The sensory integrative approach is a formulated activity plan that helps people who haven't been able to develop their own sensory recognition program. This plan allows a child to integrate all sorts of different sensory activities in their day so they can engage in and begin to work with a wide variety of sensory inputs. This provides a wide number of benefits. Their focus and attention span increases because they won't have meltdowns from trying to process too much information; sensory integrative approach helps to rebuild/reform the child's nervous system. This allows them to physically handle more sensory input. As a result, OT has been proven effective in working with children with ASD.


2020 ◽  
Vol 2 (7) ◽  
pp. 4-9
Author(s):  
Shripriya Singh

The olfactory sense is a potent sensory tool which helps us perceive our environment much better. However, smells despite being similar have different impacts on individuals. What makes one odor categorically different from the other and why do people have a unique and personalized experience with smell is an answer that needs to be addressed. In the present article we have discussed the research in which neuroscientists have decoded and described how the relationships between different odors are encoded in the brain. How the brain transforms information about odor chemistry into the perception of smell is a major highlight of this publication. Carefully selected odors with defined molecular structures were delivered in mice and the neural activity was analyzed. It was observed that neuronal representations of smell in the cortex reflected chemical similarities between odors, thus allowing the brain to categorize scents. The study has employed chemo informatics and multiphoton imaging in the mouse to demonstrate both the piriform cortex and its sensory inputs from the olfactory bulb represent chemical odor relationships through correlated patterns of activity. The research has given us cues in the direction of how the brain translates odor chemistry into neurochemistry and eventually perception of smell.


2009 ◽  
Vol 15 (1) ◽  
pp. 59-67 ◽  
Author(s):  
D Cattaneo ◽  
J Jonsdottir

Balance disorders and falls are frequently observed in subjects with multiple sclerosis (MS). Along with motor impairment, sensory disorders and integration deficits of sensory inputs lead to inadequate motor responses. The assessment of these sensory disorders in an every day tasks, such as upright stance, increases our knowledge of postural control in this pathology, thus promoting more effective treatments. The aim of the study was to describe sensory impairments and sensory strategies in different sensory conditions. A stabilometric assessment was carried out in a consecutive convenience sample of 53 subjects. The age of the sample was 52.7 (21.1) years; the onset of pathology was 27.20 (14.5) years before the assessment. Balance was assessed in six sensory conditions. The impact of pathology on balance control was shown by the high percentage of abnormal scores: 75% of subjects with MS showed abnormal scores even in the eyes open condition. The alteration of a single sensory input led to an increase of abnormal scores in up to 82% of subjects. Almost all subjects showed abnormal scores in the vestibular conditions where 22% of them fell. The pattern of the subjects’ performance in the six sensory conditions suggests that balance control may be more correlated to the number of reliable sensory inputs than the nature of the sensory input itself.


2016 ◽  
Vol 116 (2) ◽  
pp. 812-824 ◽  
Author(s):  
Samuel Andrew Hires ◽  
Adam Schuyler ◽  
Jonathan Sy ◽  
Vincent Huang ◽  
Isis Wyche ◽  
...  

The sense of touch is represented by neural activity patterns evoked by mechanosensory input forces. The rodent whisker system is exceptional for studying the neurophysiology of touch in part because these forces can be precisely computed from video of whisker deformation. We evaluate the accuracy of a standard model of whisker bending, which assumes quasi-static dynamics and a linearly tapered conical profile, using controlled whisker deflections. We find significant discrepancies between model and experiment: real whiskers bend more than predicted upon contact at locations in the middle of the whisker and less at distal locations. Thus whiskers behave as if their stiffness near the base and near the tip is larger than expected for a homogeneous cone. We assess whether contact direction, friction, inhomogeneous elasticity, whisker orientation, or nonconical shape could explain these deviations. We show that a thin-middle taper of mouse whisker shape accounts for the majority of this behavior. This taper is conserved across rows and columns of the whisker array. The taper has a large effect on the touch-evoked forces and the ease with which whiskers slip past objects, which are key drivers of neural activity in tactile object localization and identification. This holds for orientations with intrinsic whisker curvature pointed toward, away from, or down from objects, validating two-dimensional models of simple whisker-object interactions. The precision of computational models relating sensory input forces to neural activity patterns can be quantitatively enhanced by taking thin-middle taper into account with a simple corrective function that we provide.


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