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

Author(s):  
Erik Böhm ◽  
Daniela Brunert ◽  
Markus Rothermel

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.

Author(s):  
Daniela Brunert ◽  
Markus Rothermel

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.


2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush

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.


2020 ◽  
Author(s):  
Daniel Zavitz ◽  
Isaac A. Youngstrom ◽  
Alla Borisyuk ◽  
Matt Wachowiak

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.


2021 ◽  
Author(s):  
Aliya Mari Adefuin ◽  
Janine K Reinert ◽  
Sannder Lindeman ◽  
Izumi Fukunaga

Sensory systems are often tasked to analyse complex signals from the environment, to separate relevant from irrelevant parts. This process of decomposing signals is challenging when component signals interfere with each other. For example, when a mixture of signals does not equal the sum of its parts, this leads to an unpredictable corruption of signal patterns, making the target recognition harder. In olfaction, nonlinear summation is prevalent at various stages of sensory processing, from stimulus transduction in the nasal epithelium to higher areas, including the olfactory bulb (OB) and the piriform cortex. Here, we investigate how the olfactory system deals with binary mixtures of odours, using two-photon imaging with several behavioural paradigms. Unlike previous studies using anaesthetised animals, we found the mixture summation to be substantially more linear when using awake, head-fixed mice performing an odour detection task. This linearisation was also observed in awake, untrained mice, in both engaged and disengaged states, revealing that the bulk of the difference in mixture summation is explained by the brain state. However, in the apical dendrites of M/T cells, mixture representation is dominated by sublinear summation. Altogether, our results demonstrate that the property of mixture representation in the primary olfactory area likely reflects state-dependent differences in sensory processing.


2021 ◽  
Author(s):  
Daphné Rimsky-Robert ◽  
Matteo Lisi ◽  
Camille Noûs ◽  
Claire Sergent

AbstractDoes conscious perception occur during initial sensory processing, or does it arise later in a supra modal fashion? If conscious access truly depends on supra modal processes, we may be able to induce “asensory perception”, where only the semantic features of a meaningful stimulus are accessed, untied to its sensory attributes. Here we tested this prediction by degrading the low-level sensory representations of visual words in the brain using pattern masking, and subsequently presenting audio words that were either semantically related to the masked word or not. We hypothesized these retrospective semantic cues would reactivate the remaining traces of the masked word in the brain, and induce awareness of any information that was not disrupted by masking. In three separate experiments we show that, when presented with retrospective cues that are semantically related to the masked word, participants are better at detecting the presence of the preceding masked word and naming it, while at the same time being unable to report its visual features. In other words, participants could consciously detect and recognize the preceding masked word, without knowing what it looked like. These findings suggest that non-sensory information can be consciously accessed in relative independence from the build-up of sensory representations.


2017 ◽  
Author(s):  
Yosef Singer ◽  
Yayoi Teramoto ◽  
Ben D. B. WiIJmore ◽  
Andrew J. King ◽  
Jan W. H. Schnupp ◽  
...  

Neurons in sensory cortex are tuned to diverse features in natural scenes. But what determines which features neurons become selective to? Here we explore the idea that neuronal selectivity is optimised to represent features in the recent past of sensory input that best predict immediate future inputs. We tested this hypothesis using simple feedforward neural networks, which were trained to predict the next few video or audio frames in clips of natural scenes. The networks developed receptive fields that closely matched those of real cortical neurons, including the oriented spatial tuning of primary visual cortex, the frequency selectivity of primary auditory cortex and, most notably, in their temporal tuning properties. Furthermore, the better a network predicted future inputs the more closely its receptive fields tended to resemble those in the brain. This suggests that sensory processing is optimised to extract those features with the most capacity to predict future input.Impact statementPrediction of future input explains diverse neural tuning properties in sensory cortex.


2019 ◽  
Vol 3 (2) ◽  
pp. 367
Author(s):  
Sila Paramita ◽  
Naomi Soetikno ◽  
Florencia Irena

Perkembangan sensori merupakan perkembangan penting bagi individu. Sejak lahir, individu mulai memproses informasi sensori yang diperoleh dari lingkungan. Setiap informasi yang diterima sensori individu akan diintegrasikan dan diolah di otak sehingga menampilkan respons perilaku adaptif. Integrasi sensori dapat membantu individu untuk menguasai kemampuan dasar, seperti bahasa, pengendalian emosi, dan kemampuan berhitung. Masalah dalam integrasi sensori berkaitan dengan masalah dalam pemrosesan informasi sensori yang dikenal sebagai Regulatory Sensory Processing Disorder (RSPD). Ketika individu mengalami masalah dalam pemrosesan informasi sensori, maka individu akan mengalami hambatan baik dalam keberfungsiannya sehari-hari maupun perkembangannya. Masalah sensori dapat dikenali sejak dini melalui karakteristik perilaku yang ditampilkan anak. Oleh sebab itu, penelitian ini bertujuan untuk mengetahui gambaran perilaku anak dengan Regulatory Sensory Processing Disorder. Penelitian ini merupakan penelitian kualitatif dengan metode studi kasus. Partisipan dalam penelitian ini berjumlah satu orang yang merupakan pasien anak pada Klinik Tumbuh Kembang X. Metode pengambilan data menggunakan observasi, wawancara, dan asesmen psikologi. Ada pun sumber informasi diperoleh langsung melalui partisipan, orangtua, dan terapis. Untuk mengetahui gambaran fungsi sensori pada partisipan, peneliti menggunakan daftar observasi wawancara yang tertera pada ICDL-DMIC (2005). Hasil penelitian menunjukkan bahwa partisipan yang terlibat dalam penelitian ini mengalami gangguan pemrosesan sensori dengan tipe sensory-seeking. Partisipan penelitian menampilkan perilaku yang sangat aktif bergerak dan kesulitan memberikan atensi pada tugas yang diberikan. Hal tersebut berdampak pada performa akademis dan interaksi sosial yang dimiliki. Sensory development is an important development for individuals. From birth, individuals begin to process sensory information obtained from the environment. Every information received by an individual sensory receptor will be integrated and processed in the brain so that it displays an adaptive behavioral response. Sensory integration can help individuals to master basic abilities, such as language, emotional control, and numeracy skills. Problems in sensory integration are related to problems in processing sensory information known as Regulatory Sensory Processing Disorder (RSPD). When individuals experience problems in processing sensory information, individuals will experience obstacles both in their daily functioning and development. Sensory problems can be recognized early on through the behavioral characteristics displayed by children. Therefore, this study aims to describe the behaviour of children with Regulatory Sensory Processing Disorder. This research is a qualitative research with case study method. The sole participant in this study is a pediatric patient in the Growth and Development Clinic X. Data collection used observation, interviews, and psychological assessment. Information was also obtained directly through participants, parents, and therapists. To find out the description of sensory functions in participants, researchers used the interview observation list listed in ICDL-DMIC (2005). The results showed that the participants involved in this study experienced sensory-seeking type sensory processing disorders. Participant displayed very active behavior and difficulty in attending to the tasks assigned. This has an impact on academic performance and social interactions.


Author(s):  
Aleksandra Polosukhina ◽  
Pierre-Marie Lledo

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.


2010 ◽  
Vol 103 (3) ◽  
pp. 1147-1157 ◽  
Author(s):  
Akio Hirata ◽  
Manuel A. Castro-Alamancos

Neocortex network activity varies from a desynchronized or activated state typical of arousal to a synchronized or deactivated state typical of quiescence. Such changes are usually attributed to the effects of neuromodulators released in the neocortex by nonspecific activating systems originating in basal forebrain and brain stem reticular formation. As a result, the only role attributed to thalamocortical cells projecting to primary sensory areas, such as barrel cortex, is to transmit sensory information. However, thalamocortical cells can undergo significant changes in spontaneous tonic firing as a function of state, although the role of such variations is unknown. Here we show that the tonic firing level of thalamocortical cells, produced by cholinergic and noradrenergic stimulation of the somatosensory thalamus in urethane-anesthetized rats, controls neocortex activation and deactivation. Thus in addition to its well-known role in the relay of sensory information, the thalamus can control the state of neocortex activation, which may complement the established roles in this regard of basal forebrain and brain stem nuclei. Because of the topographical organization of primary thalamocortical pathways, this mechanism provides a means by which area-specific neocortical activation can occur, which may be useful for modality-specific sensory processing or selective attention.


2012 ◽  
Vol 279 (1746) ◽  
pp. 4399-4406 ◽  
Author(s):  
Nobuhiro Hagura ◽  
Ryota Kanai ◽  
Guido Orgs ◽  
Patrick Haggard

Professional ball game players report the feeling of the ball ‘slowing-down’ before hitting it. Because effective motor preparation is critical in achieving such expert motor performance, these anecdotal comments imply that the subjective passage of time may be influenced by preparation for action. Previous reports of temporal illusions associated with action generally emphasize compensation for suppressed sensory signals that accompany motor commands. Here, we show that the time is perceived slowed-down during preparation of a ballistic reaching movement before action, involving enhancement of sensory processing. Preparing for a reaching movement increased perceived duration of a visual stimulus. This effect was tightly linked to action preparation, because the amount of temporal dilation increased with the information about the upcoming movement. Furthermore, we showed a reduction of perceived frequency for flickering stimuli and an enhanced detection of rapidly presented letters during action preparation, suggesting increased temporal resolution of visual perception during action preparation. We propose that the temporal dilation during action preparation reflects the function of the brain to maximize the capacity of sensory information-acquisition prior to execution of a ballistic movement. This strategy might facilitate changing or inhibiting the planned action in response to last-minute changes in the external environment.


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