scholarly journals Extrinsic neuromodulation in the rodent olfactory bulb

2020 ◽  
Author(s):  
Daniela Brunert ◽  
Markus Rothermel
Keyword(s):  
Olfactory Bulb ◽  
Sensory Input ◽  
Sensory Information ◽  
Special Importance ◽  
Relay Station ◽  
Future Directions ◽  
The Brain

AbstractEvolutionarily, olfaction is one of the oldest senses and pivotal for an individual’s health and survival. The olfactory bulb (OB), as the first olfactory relay station in the brain, is known to heavily process sensory information. To adapt to an animal’s needs, OB activity can be influenced by many factors either from within (intrinsic neuromodulation) or outside (extrinsic neuromodulation) the OB which include neurotransmitters, neuromodulators, hormones, and neuropeptides. Extrinsic sources seem to be of special importance as the OB receives massive efferent input from numerous brain centers even outweighing the sensory input from the nose. Here, we review neuromodulatory processes in the rodent OB from such extrinsic sources. We will discuss extrinsic neuromodulation according to points of origin, receptors involved, affected circuits, and changes in behavior. In the end, we give a brief outlook on potential future directions in research on neuromodulation in the OB.

scholarly journals Input dependent modulation of olfactory bulb activity by GABAergic basal forebrain projections

2020 ◽  
Author(s):  
Erik Böhm ◽  
Daniela Brunert ◽  
Markus Rothermel
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Basal Forebrain ◽  
Sensory Input ◽  
Sensory Information ◽  
Neuron Activity ◽  
Differential Modulation ◽  
Cholinergic Basal Forebrain ◽  
The Brain ◽  
Cholinergic Projections

AbstractBasal forebrain modulation of central circuits is associated with active sensation, attention and learning. While cholinergic modulations have been studied extensively the effect of non-cholinergic basal forebrain subpopulations on sensory processing remains largely unclear. Here, we directly compare optogenetic manipulation effects of two major basal forebrain subpopulations on principal neuron activity in an early sensory processing area, i.e. mitral/tufted cells (MTCs) in the olfactory bulb. In contrast to cholinergic projections, which consistently increased MTC firing, activation of GABAergic fibers from basal forebrain to the olfactory bulb lead to differential modulation effects: while spontaneous MTC activity is mainly inhibited, odor evoked firing is predominantly enhanced. Moreover, sniff triggered averages revealed an enhancement of maximal sniff evoked firing amplitude and an inhibition of firing rates outside the maximal sniff phase. These findings demonstrate that GABAergic neuromodulation affects MTC firing in a bimodal, sensory-input dependent way, suggesting that GABAergic basal forebrain modulation could be an important factor in attention mediated filtering of sensory information to the brain.

scholarly journals The emulation theory of representation: Motor control, imagery, and perception

2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush
Keyword(s):  
Motor Control ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Neural Circuits ◽  
Sensory Information ◽  
The Body ◽  
Feedback Delay ◽  
Run Off ◽  
Effects Of Feedback ◽  
The Brain

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.

scholarly journals Effect of interglomerular inhibitory networks on olfactory bulb odor representations

2020 ◽  
Author(s):  
Daniel Zavitz ◽  
Isaac A. Youngstrom ◽  
Alla Borisyuk ◽  
Matt Wachowiak
Keyword(s):  
Experimental Data ◽  
Olfactory Bulb ◽  
Computational Model ◽  
Lateral Inhibition ◽  
Sensory Input ◽  
Sensory Information ◽  
Gain Control ◽  
Innervation Patterns ◽  
Cell Networks ◽  
Inhibitory Networks

AbstractLateral inhibition is a fundamental feature of circuits that process sensory information. In the mammalian olfactory system, inhibitory interneurons called short axon cells comprise the first network mediating lateral inhibition between glomeruli, the functional units of early olfactory coding and processing. The connectivity of this network and its impact on odor representations is not well understood. To explore this question, we constructed a computational model of the interglomerular inhibitory network using detailed characterizations of short axon cell morphologies taken from mouse olfactory bulb. We then examined how this network transformed glomerular patterns of odorant-evoked sensory input (taken from previously-published datasets) as a function of the selectivity of interglomerular inhibition. We examined three connectivity schemes: selective (each glomerulus connects to few others with heterogeneous strength), nonselective (glomeruli connect to most others with heterogenous strength) or global (glomeruli connect to all others with equal strength). We found that both selective and nonselective interglomerular networks could mediate heterogeneous patterns of inhibition across glomeruli when driven by realistic sensory input patterns, but that global inhibitory networks were unable to produce input-output transformations that matched experimental data and were poor mediators of intensity-dependent gain control. We further found that networks whose interglomerular connectivity was tuned by sensory input profile decorrelated odor representations more effectively. These results suggest that, despite their multiglomerular innervation patterns, short axon cells are capable of mediating odorant-specific patterns of inhibition between glomeruli that could, theoretically, be tuned by experience or evolution to optimize discrimination of particular odorants.Significance StatementLateral inhibition is a key feature of circuitry in many sensory systems including vision, audition, and olfaction. We investigate how lateral inhibitory networks mediated by short axon cells in the mouse olfactory bulb might shape odor representations as a function of their interglomerular connectivity. Using a computational model of interglomerular connectivity derived from experimental data, we find that short axon cell networks, despite their broad innervation patterns, can mediate heterogeneous patterns of inhibition across glomeruli, and that the canonical model of global inhibition does not generate experimentally observed responses to stimuli. In addition, inhibitory connections tuned by input statistics yield enhanced decorrelation of similar input patterns. These results elucidate how the organization of inhibition between neural elements may affect computations.

Postnatal Neurogenesis in the Olfactory Bulb

2016 ◽  
Author(s):  
Aleksandra Polosukhina ◽  
Pierre-Marie Lledo
Keyword(s):  
Olfactory Bulb ◽  
Granule Cells ◽  
Sensory Information ◽  
Adult Brain ◽  
Sensory Function ◽  
The Other ◽  
Forthcoming Article ◽  
Adult Born Neurons ◽  
Newborn Neurons ◽  
The Brain

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Neuroscience. Please check back later for the full article. In adult mammals, the olfactory bulb and the hippocampus are the regions in the brain that undergo continuous neurogenesis (production and recruitment of newborn neurons). While the other regions of the brain still retain a certain degree of plasticity after birth, they no longer can integrate new neurons. In rodents, thousands of adult-born neurons integrate into the bulb each day, and this process has been found to contribute not only to sensory function, but also to olfactory memory. This was a surprising finding, since historically the adult-brain has been viewed as a static organ. Understanding the process of regeneration of mature neurons in the brain has great potential for therapeutic applications. Consequently, this process of adult-neurogenesis has received widespread attention from clinicians and scientists. Neuroblasts bound for the olfactory bulb are produced in the subventricular zone of the lateral ventricle. Once they reach the olfactory bulb, they mostly develop into inhibitory interneurons called granule cells. Just after one month, about half of the adult-born neurons are eliminated, and the other half fully integrate and function in the olfactory bulb. These cells not only process information from the sensory neurons in the bulb, but also receive massive innervation from various regions of the brain, including the olfactory cortex, locus coeruleus, the horizontal limb of diagonal band of Broca, and the dorsal raphe nucleus. The sensory (bottom-up) and cortical (top-down) activity has been found to play a vital role in the adult-born granule cell survival. Though the exact purpose of these newborn neurons has not been identified, some emerging functions include maintenance of olfactory bulb circuitry, modulating sensory information, modulating olfactory learning, and memory.

scholarly journals Predictions drive neural representations of visual events ahead of incoming sensory information

2020 ◽  
Vol 117 (13) ◽  
pp. 7510-7515 ◽  
Author(s):  
Tessel Blom ◽  
Daniel Feuerriegel ◽  
Philippa Johnson ◽  
Stefan Bode ◽  
Hinze Hogendoorn
Keyword(s):  
Visual System ◽  
Real Time ◽  
Visual Information ◽  
Sensory Input ◽  
Sensory Information ◽  
Moving Object ◽  
Present Moment ◽  
Neural Representations ◽  
The Brain ◽  
Predictive Mechanisms

The transmission of sensory information through the visual system takes time. As a result of these delays, the visual information available to the brain always lags behind the timing of events in the present moment. Compensating for these delays is crucial for functioning within dynamic environments, since interacting with a moving object (e.g., catching a ball) requires real-time localization of the object. One way the brain might achieve this is via prediction of anticipated events. Using time-resolved decoding of electroencephalographic (EEG) data, we demonstrate that the visual system represents the anticipated future position of a moving object, showing that predictive mechanisms activate the same neural representations as afferent sensory input. Importantly, this activation is evident before sensory input corresponding to the stimulus position is able to arrive. Finally, we demonstrate that, when predicted events do not eventuate, sensory information arrives too late to prevent the visual system from representing what was expected but never presented. Taken together, we demonstrate how the visual system can implement predictive mechanisms to preactivate sensory representations, and argue that this might allow it to compensate for its own temporal constraints, allowing us to interact with dynamic visual environments in real time.

scholarly journals Generalization of prior information for rapid Bayesian time estimation

2016 ◽  
Vol 114 (2) ◽  
pp. 412-417 ◽  
Author(s):  
Neil W. Roach ◽  
Paul V. McGraw ◽  
David J. Whitaker ◽  
James Heron
Keyword(s):  
Sensory Input ◽  
Prior Information ◽  
Effective Interaction ◽  
Sensory Information ◽  
Time Estimation ◽  
Large Set ◽  
Ample Evidence ◽  
Competing Demands ◽  
Statistical Regularities ◽  
The Brain

To enable effective interaction with the environment, the brain combines noisy sensory information with expectations based on prior experience. There is ample evidence showing that humans can learn statistical regularities in sensory input and exploit this knowledge to improve perceptual decisions and actions. However, fundamental questions remain regarding how priors are learned and how they generalize to different sensory and behavioral contexts. In principle, maintaining a large set of highly specific priors may be inefficient and restrict the speed at which expectations can be formed and updated in response to changes in the environment. However, priors formed by generalizing across varying contexts may not be accurate. Here, we exploit rapidly induced contextual biases in duration reproduction to reveal how these competing demands are resolved during the early stages of prior acquisition. We show that observers initially form a single prior by generalizing across duration distributions coupled with distinct sensory signals. In contrast, they form multiple priors if distributions are coupled with distinct motor outputs. Together, our findings suggest that rapid prior acquisition is facilitated by generalization across experiences of different sensory inputs but organized according to how that sensory information is acted on.

scholarly journals The brain detects stimulus features, but not stimulus conflict in task-irrelevant sensory input

2019 ◽  
Author(s):  
Stijn A. Nuiten ◽  
Andrés Canales-Johnson ◽  
Lola Beerendonk ◽  
Nutsa Nanuashvili ◽  
Johannes J. Fahrenfort ◽  
...  
Keyword(s):  
Sensory Input ◽  
Sensory Information ◽  
Past Research ◽  
Conflict Detection ◽  
Information Analysis ◽  
Task Relevance ◽  
Human Participants ◽  
Stimulus Features ◽  
Task Irrelevant ◽  
The Brain

AbstractCognitive control over conflicting sensory input is central to adaptive human behavior. It might therefore not come as a surprise that past research has shown conflict detection in the absence of conscious awareness. This would suggest that the brain may detect conflict fully automatically, and that it can even occur without paying attention. Contrary to this intuition, we show that task-relevance is crucial for conflict detection. Univariate and multivariate analyses on electroencephalographic data from human participants revealed that when auditory stimuli are fully task-irrelevant, the brain disregards conflicting input entirely, whereas the same input elicits strong neural conflict signals when task-relevant. In sharp contrast, stimulus features were still processed, irrespective of task-relevance. These results show that stimulus properties are only integrated to allow conflict to be detected by prefrontal regions when sensory information is task-relevant and therefore suggests an attentional bottleneck at high levels of information analysis.

scholarly journals Increase in Mutual Information During Interaction of the Brain with Environment Contributes to Perception

2019 ◽  
Author(s):  
Daya Gupta ◽  
Andreas Bahmer
Keyword(s):  
Mutual Information ◽  
Sensory Input ◽  
Neural Circuits ◽  
Probability Distributions ◽  
Sensory Information ◽  
Hierarchical Level ◽  
Temporal Coupling ◽  
The Given ◽  
The Brain ◽  
Motor Interaction

Perception and motor interaction with physical surroundings can be analyzed by the changes in probability laws governing two possible outcomes of neuronal activity, namely the presence or absence of spikes (binary states). Perception and motor interaction with physical environment are accounted partly by the reduction in entropy within the probability distributions of binary states of neurons in distributed neural circuits, given the knowledge about the characteristics of stimuli in physical surroundings. This reduction in the total entropy of multiple pairs of circuits in networks, by an amount equal to the increase of mutual information among them, occurs as sensory information is processed successively from lower to higher cortical areas or between different areas at the same hierarchical level but belonging to different networks. The increase in mutual information is partly accounted by temporal coupling as well as synaptic connections as proposed by Bahmer and Gupta [1]. We propose that robust increases in mutual information, measuring the association between the characteristics of sensory inputs and neural circuits connectivity patterns, are partly responsible for perception and successful motor interactions with physical surroundings. It is also argued that perception from a sensory input is the result of networking of many circuits to a common circuit that primarily processes the given sensory input.

Relation Between Level of Prefrontal Activity and Subject's Performance

1999 ◽  
Vol 13 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Laurence Casini ◽  
Françoise Macar ◽  
Marie-Hélène Giard
Keyword(s):  
Brain Activity ◽  
Sensory Information ◽  
Practice Phase ◽  
Trained Subjects ◽  
Anagram Task ◽  
Economic Information ◽  
Long Duration ◽  
Level Of Activity ◽  
The Brain ◽  
Processing Mechanism

Abstract The experiment reported here was aimed at determining whether the level of brain activity can be related to performance in trained subjects. Two tasks were compared: a temporal and a linguistic task. An array of four letters appeared on a screen. In the temporal task, subjects had to decide whether the letters remained on the screen for a short or a long duration as learned in a practice phase. In the linguistic task, they had to determine whether the four letters could form a word or not (anagram task). These tasks allowed us to compare the level of brain activity obtained in correct and incorrect responses. The current density measures recorded over prefrontal areas showed a relationship between the performance and the level of activity in the temporal task only. The level of activity obtained with correct responses was lower than that obtained with incorrect responses. This suggests that a good temporal performance could be the result of an efficacious, but economic, information-processing mechanism in the brain. In addition, the absence of this relation in the anagram task results in the question of whether this relation is specific to the processing of sensory information only.

Alcohol Use Disorder

2018 ◽  
Author(s):  
Igor Ponomarev
Keyword(s):  
Alcohol Use ◽  
Alcohol Use Disorder ◽  
Critical Discussion ◽  
Epigenetic Mechanisms ◽  
Future Directions ◽  
Clinically Significant ◽  
Early Life Exposures ◽  
The Brain ◽  
Epigenetic Research

Alcohol use disorder (AUD) is characterized by clinically significant impairments in health and social function. Epigenetic mechanisms of gene regulation may provide an attractive explanation for how early life exposures to alcohol contribute to the development of AUD and exert lifelong effects on the brain. This chapter provides a critical discussion of the role of epigenetic mechanisms in AUD etiology and the potential of epigenetic research to improve diagnosis, evaluate risks for alcohol-induced pathologies, and promote development of novel therapies for the prevention and treatment of AUD. Challenges of the current epigenetic approaches and future directions are also discussed.

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