scholarly journals Serotonergic modulation across sensory modalities

2020 ◽  
Vol 123 (6) ◽  
pp. 2406-2425
Author(s):  
Tyler R. Sizemore ◽  
Laura M. Hurley ◽  
Andrew M. Dacks
Keyword(s):  
Serotonin Receptor ◽  
Physiological State ◽  
Sensory Information ◽  
Specific Stimulus ◽  
Sensory Organization ◽  
Sensory Modalities ◽  
Multiple Levels ◽  
Stimulus Features ◽  
Ubiquitous Presence ◽  
Serotonergic Modulation

The serotonergic system has been widely studied across animal taxa and different functional networks. This modulatory system is therefore well positioned to compare the consequences of neuromodulation for sensory processing across species and modalities at multiple levels of sensory organization. Serotonergic neurons that innervate sensory networks often bidirectionally exchange information with these networks but also receive input representative of motor events or motivational state. This convergence of information supports serotonin’s capacity for contextualizing sensory information according to the animal’s physiological state and external events. At the level of sensory circuitry, serotonin can have variable effects due to differential projections across specific sensory subregions, as well as differential serotonin receptor type expression within those subregions. Functionally, this infrastructure may gate or filter sensory inputs to emphasize specific stimulus features or select among different streams of information. The near-ubiquitous presence of serotonin and other neuromodulators within sensory regions, coupled with their strong effects on stimulus representation, suggests that these signaling pathways should be considered integral components of sensory systems.

scholarly journals Distinct lateral inhibitory circuits drive parallel processing of sensory information in the mammalian olfactory bulb

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Matthew A Geramita ◽  
Shawn D Burton ◽  
Nathan N Urban
Keyword(s):  
Granule Cells ◽  
Sensory Information ◽  
Cell Types ◽  
Specific Stimulus ◽  
Inhibitory Circuits ◽  
Parallel Pathways ◽  
Common Strategy ◽  
Feature Selectivity ◽  
Tufted Cells ◽  
Stimulus Features

Splitting sensory information into parallel pathways is a common strategy in sensory systems. Yet, how circuits in these parallel pathways are composed to maintain or even enhance the encoding of specific stimulus features is poorly understood. Here, we have investigated the parallel pathways formed by mitral and tufted cells of the olfactory system in mice and characterized the emergence of feature selectivity in these cell types via distinct lateral inhibitory circuits. We find differences in activity-dependent lateral inhibition between mitral and tufted cells that likely reflect newly described differences in the activation of deep and superficial granule cells. Simulations show that these circuit-level differences allow mitral and tufted cells to best discriminate odors in separate concentration ranges, indicating that segregating information about different ranges of stimulus intensity may be an important function of these parallel sensory pathways.

scholarly journals Inhibition of SK and M channel-mediated currents by 5-HT enables parallel processing by bursts and isolated spikes

2011 ◽  
Vol 105 (3) ◽  
pp. 1276-1294 ◽  
Author(s):  
Tara Deemyad ◽  
Leonard Maler ◽  
Maurice J. Chacron
Keyword(s):  
Pyramidal Neurons ◽  
Sensory Information ◽  
Burst Firing ◽  
Weakly Electric Fish ◽  
Specific Stimulus ◽  
Communication Signals ◽  
Electrophysiological Recordings ◽  
Firing Mode ◽  
Stimulus Features ◽  
Weakly Electric

Although serotonergic innervation of sensory brain areas is ubiquitous, its effects on sensory information processing remain poorly understood. We investigated these effects in pyramidal neurons within the electrosensory lateral line lobe (ELL) of weakly electric fish. Surprisingly, we found that 5-HT is present at different levels across the different ELL maps; the presence of 5-HT fibers was highest in the map that processes intraspecies communication signals. Electrophysiological recordings revealed that 5-HT increased excitability and burst firing through a decreased medium afterhyperpolarization resulting from reduced small-conductance calcium-activated (SK) currents as well as currents mediated by an M-type potassium channel. We next investigated how 5-HT alters responses to sensory input. 5-HT application decreased the rheobase current, increased the gain, and decreased first spike latency. Moreover, it reduced discriminability between different stimuli, as quantified by the mutual information rate. We hypothesized that 5-HT shifts pyramidal neurons into a burst-firing mode where bursts, when considered as events, can detect the presence of particular stimulus features. We verified this hypothesis using signal detection theory. Our results indeed show that serotonin-induced bursts of action potentials, when considered as events, could detect specific stimulus features that were distinct from those detected by isolated spikes. Moreover, we show the novel result that isolated spikes transmit more information after 5-HT application. Our results suggest a novel function for 5-HT in that it enables differential processing by action potential patterns in response to current injection.

scholarly journals Autofluorescence Is a Common Trait in Different Oceanic Fungi

2021 ◽  
Vol 7 (9) ◽  
pp. 709
Author(s):  
Eva Breyer ◽  
Markus Böhm ◽  
Magdalena Reitbauer ◽  
Chie Amano ◽  
Marilena Heitger ◽  
...  
Keyword(s):  
Marine Fungi ◽  
Physiological State ◽  
Excitation Wavelength ◽  
Growth Stages ◽  
Future Studies ◽  
Different Types ◽  
Widespread Phenomenon ◽  
Ubiquitous Presence ◽  
Different Growth Stages

Natural autofluorescence is a widespread phenomenon observed in different types of tissues and organisms. Depending on the origin of the autofluorescence, its intensity can provide insights on the physiological state of an organism. Fungal autofluorescence has been reported in terrestrial and human-derived fungal samples. Yet, despite the recently reported ubiquitous presence and importance of marine fungi in the ocean, the autofluorescence of pelagic fungi has never been examined. Here, we investigated the existence and intensity of autofluorescence in five different pelagic fungal isolates. Preliminary experiments of fungal autofluorescence at different growth stages and nutrient conditions were conducted, reflecting contrasting physiological states of the fungi. In addition, we analysed the effect of natural autofluorescence on co-staining with DAPI. We found that all the marine pelagic fungi that were studied exhibited autofluorescence. The intensity of fungal autofluorescence changed depending on the species and the excitation wavelength used. Furthermore, fungal autofluorescence varied depending on the growth stage and on the concentration of available nutrients. Collectively, our results indicate that marine fungi can be auto-fluorescent, although its intensity depends on the species and growth condition. Hence, oceanic fungal autofluorescence should be considered in future studies when fungal samples are stained with fluorescent probes (i.e., fluorescence in situ hybridization) since this could lead to misinterpretation of results.

scholarly journals Neural evidence supports a dual sensory-motor role for insect wings

2017 ◽  
Vol 284 (1862) ◽  
pp. 20170969 ◽  
Author(s):  
Brandon Pratt ◽  
Tanvi Deora ◽  
Thomas Mohren ◽  
Thomas Daniel
Keyword(s):  
Flight Control ◽  
Information Acquisition ◽  
Receptive Fields ◽  
Mechanical Stimulus ◽  
Sensory Function ◽  
Computational Techniques ◽  
Campaniform Sensilla ◽  
Specific Stimulus ◽  
Processing Times ◽  
Stimulus Features

Flying insects use feedback from various sensory modalities including vision and mechanosensation to navigate through their environment. The rapid speed of mechanosensory information acquisition and processing compensates for the slower processing times associated with vision, particularly under low light conditions. While halteres in dipteran species are well known to provide such information for flight control, less is understood about the mechanosensory roles of their evolutionary antecedent, wings. The features that wing mechanosensory neurons (campaniform sensilla) encode remains relatively unexplored. We hypothesized that the wing campaniform sensilla of the hawkmoth, Manduca sexta, rapidly and selectively extract mechanical stimulus features in a manner similar to halteres. We used electrophysiological and computational techniques to characterize the encoding properties of wing campaniform sensilla. To accomplish this, we developed a novel technique for localizing receptive fields using a focused IR laser that elicits changes in the neural activity of mechanoreceptors. We found that (i) most wing mechanosensors encoded mechanical stimulus features rapidly and precisely, (ii) they are selective for specific stimulus features, and (iii) there is diversity in the encoding properties of wing campaniform sensilla. We found that the encoding properties of wing campaniform sensilla are similar to those for haltere neurons. Therefore, it appears that the neural architecture that underlies the haltere sensory function is present in wings, which lends credence to the notion that wings themselves may serve a similar sensory function. Thus, wings may not only function as the primary actuator of the organism but also as sensors of the inertial dynamics of the animal.

Sensory Substitution Devices as Advanced Sensory Tools

2018 ◽  
pp. 188-204
Author(s):  
Thomas D. Wright ◽  
Jamie Ward
Keyword(s):  
Nervous System ◽  
Sensory Information ◽  
Sensory Substitution ◽  
Considerable Effort ◽  
Conceptual Space ◽  
System P ◽  
Starting Point ◽  
Sensory Modalities ◽  
Magnetic Sense ◽  
Definition Of

There has been considerable effort devoted towards understanding sensory substitution devices in terms of their relationship to canonical sensory modalities. The approach taken in this essay is rather different, although complementary, in that we seek to define a broad conceptual space of ‘sensory tools’ in which sensory substitution devices can be situated. Such devices range from telescopes, to cochlear implants, to attempts to create a magnetic sense. One feature of these devices is that they operate at the level of ‘raw’ sensory information. As such, systems such as Braille which operate at a symbolic/conceptual level do not count as a sensory tool (or a sensory substitution device) and nor would a device such as CCTV which, although capturing raw sensory information, would not meet a conventional definition of a tool. With this approach, we hope to avoid the circularity inherent in previous attempts at defining sensory substitution and provide a better starting point to explore the effects of sensory tools, more generally, on the functioning of the nervous system.

scholarly journals Left-Hemispheric Asymmetry for Object-Based Attention: an ERP Study

2019 ◽  
Vol 9 (11) ◽  
pp. 315 ◽  
Author(s):  
Andrea Orlandi ◽  
Alice Mado Proverbio
Keyword(s):  
Visual Attention ◽  
Hemispheric Asymmetry ◽  
Time Course ◽  
Electrophysiological Study ◽  
Target Selection ◽  
Neural Correlates ◽  
Specific Stimulus ◽  
Object Categories ◽  
Object Based ◽  
Stimulus Features

It has been shown that selective attention enhances the activity in visual regions associated with stimulus processing. The left hemisphere seems to have a prominent role when non-spatial attention is directed towards specific stimulus features (e.g., color, spatial frequency). The present electrophysiological study investigated the time course and neural correlates of object-based attention, under the assumption of left-hemispheric asymmetry. Twenty-nine right-handed participants were presented with 3D graphic images representing the shapes of different object categories (wooden dummies, chairs, structures of cubes) which lacked detail. They were instructed to press a button in response to a target stimulus indicated at the beginning of each run. The perception of non-target stimuli elicited a larger anterior N2 component, which was likely associated with motor inhibition. Conversely, target selection resulted in an enhanced selection negativity (SN) response lateralized over the left occipito-temporal regions, followed by a larger centro-parietal P300 response. These potentials were interpreted as indexing attentional selection and categorization processes, respectively. The standardized weighted low-resolution electromagnetic tomography (swLORETA) source reconstruction showed the engagement of a fronto-temporo-limbic network underlying object-based visual attention. Overall, the SN scalp distribution and relative neural generators hinted at a left-hemispheric advantage for non-spatial object-based visual attention.

scholarly journals Basing Perceptual Decisions on the Most Informative Sensory Neurons

2010 ◽  
Vol 104 (4) ◽  
pp. 2266-2273 ◽  
Author(s):  
Miranda Scolari ◽  
John T. Serences
Keyword(s):  
Sensory Neurons ◽  
Functional Magnetic Resonance ◽  
Relevant Stimulus ◽  
Unit Recording ◽  
Channel Activation ◽  
Specific Stimulus ◽  
Stimulus Features ◽  
Perceptual Acuity ◽  
Predictive Relationship ◽  
Extensive Practice

Single unit recording studies show that perceptual decisions are often based on the output of sensory neurons that are maximally responsive (or “tuned”) to relevant stimulus features. However, when performing a difficult discrimination between two highly similar stimuli, perceptual decisions should instead be based on the activity of neurons tuned away from the relevant feature ( off-channel neurons) as these neurons undergo a larger firing rate change and are thus more informative. To test this hypothesis, we measured feature-selective responses in human primary visual cortex (V1) using functional magnetic resonance imaging and show that the degree of off-channel activation predicts performance on a difficult visual discrimination task. Moreover, this predictive relationship between off-channel activation and perceptual acuity is not simply the result of extensive practice with a specific stimulus feature (as in studies of perceptual learning). Instead, relying on the output of the most informative sensory neurons may represent a general, and optimal, strategy for efficiently computing perceptual decisions.

Spike-Timing Precision Underlies the Coding Efficiency of Auditory Receptor Neurons

2006 ◽  
Vol 95 (4) ◽  
pp. 2541-2552 ◽  
Author(s):  
Ariel Rokem ◽  
Sebastian Watzl ◽  
Tim Gollisch ◽  
Martin Stemmler ◽  
Andreas V. M. Herz ◽  
...  
Keyword(s):  
Spike Train ◽  
Spike Trains ◽  
Neural Representation ◽  
Neural Firing ◽  
Specific Stimulus ◽  
Time Jitter ◽  
Information Rates ◽  
Communication Signals ◽  
Receptor Neurons ◽  
Stimulus Features

Sensory systems must translate incoming signals quickly and reliably so that an animal can act successfully in its environment. Even at the level of receptor neurons, however, functional aspects of the sensory encoding process are not yet fully understood. Specifically, this concerns the question how stimulus features and neural response characteristics lead to an efficient transmission of sensory information. To address this issue, we have recorded and analyzed spike trains from grasshopper auditory receptors, while systematically varying the stimulus statistics. The stimulus variations profoundly influenced the efficiency of neural encoding. This influence was largely attributable to the presence of specific stimulus features that triggered remarkably precise spikes whose trial-to-trial timing variability was as low as 0.15 ms—one order of magnitude shorter than typical stimulus time scales. Precise spikes decreased the noise entropy of the spike trains, thereby increasing the rate of information transmission. In contrast, the total spike train entropy, which quantifies the variety of different spike train patterns, hardly changed when stimulus conditions were altered, as long as the neural firing rate remained the same. This finding shows that stimulus distributions that were transmitted with high information rates did not invoke additional response patterns, but instead displayed exceptional temporal precision in their neural representation. The acoustic stimuli that led to the highest information rates and smallest spike-time jitter feature pronounced sound-pressure deflections lasting for 2–3 ms. These upstrokes are reminiscent of salient structures found in natural grasshopper communication signals, suggesting that precise spikes selectively encode particularly important aspects of the natural stimulus environment.

scholarly journals Auditory and visual scene analysis: an overview

2017 ◽  
Vol 372 (1714) ◽  
pp. 20160099 ◽  
Author(s):  
Hirohito M. Kondo ◽  
Anouk M. van Loon ◽  
Jun-Ichiro Kawahara ◽  
Brian C. J. Moore
Keyword(s):  
Scene Perception ◽  
Computational Modelling ◽  
Visual Scene ◽  
Scene Analysis ◽  
Theoretical Approaches ◽  
Visual Inputs ◽  
Sensory Modalities ◽  
Stimulus Features ◽  
The Brain ◽  
Selection Of

We perceive the world as stable and composed of discrete objects even though auditory and visual inputs are often ambiguous owing to spatial and temporal occluders and changes in the conditions of observation. This raises important questions regarding where and how ‘scene analysis’ is performed in the brain. Recent advances from both auditory and visual research suggest that the brain does not simply process the incoming scene properties. Rather, top-down processes such as attention, expectations and prior knowledge facilitate scene perception. Thus, scene analysis is linked not only with the extraction of stimulus features and formation and selection of perceptual objects, but also with selective attention, perceptual binding and awareness. This special issue covers novel advances in scene-analysis research obtained using a combination of psychophysics, computational modelling, neuroimaging and neurophysiology, and presents new empirical and theoretical approaches. For integrative understanding of scene analysis beyond and across sensory modalities, we provide a collection of 15 articles that enable comparison and integration of recent findings in auditory and visual scene analysis. This article is part of the themed issue ‘Auditory and visual scene analysis’.

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