scholarly journals State-dependent linearisation of mixture representations by the olfactory bulb

2021 ◽  
Author(s):  
Aliya Mari Adefuin ◽  
Janine K Reinert ◽  
Sannder Lindeman ◽  
Izumi Fukunaga
Keyword(s):  
Olfactory Bulb ◽  
Sensory Processing ◽  
Piriform Cortex ◽  
Brain State ◽  
Complex Signals ◽  
Two Photon ◽  
State Dependent ◽  
The Difference ◽  
Apical Dendrites ◽  
The Brain

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.

Brain-state dependent uncoupling of BOLD and local field potentials in laminar olfactory bulb

2014 ◽  
Vol 580 ◽  
pp. 1-6 ◽  
Author(s):  
Ling Gong ◽  
Bo Li ◽  
Ruiqi Wu ◽  
Anan Li ◽  
Fuqiang Xu
Keyword(s):  
Olfactory Bulb ◽  
Local Field ◽  
Local Field Potentials ◽  
Brain State ◽  
Field Potentials ◽  
State Dependent

scholarly journals Multi-functional feedforward inhibitory circuits for cortical odor processing

2021 ◽  
Author(s):  
Norimitsu Suzuki ◽  
Malinda L. S. Tantirigama ◽  
Helena H.-Y. Huang ◽  
John M. Bekkers
Keyword(s):  
Calcium Imaging ◽  
Piriform Cortex ◽  
Complex Interplay ◽  
Inhibitory Circuits ◽  
Two Photon ◽  
Odor Processing ◽  
Strong Excitation ◽  
The Brain ◽  
Feedforward Inhibition

Feedforward inhibitory circuits are key contributors to the complex interplay between excitation and inhibition in the brain. Little is known about the function of feedforward inhibition in the primary olfactory (piriform) cortex. Using in vivo two-photon targeted patch clamping and calcium imaging in mice, we find that odors evoke strong excitation in two classes of interneurons – neurogliaform (NG) cells and horizontal (HZ) cells – that provide feedforward inhibition in layer 1 of the piriform cortex. NG cells fire much earlier than HZ cells following odor onset, a difference that can be attributed to the faster odor-driven excitatory synaptic drive that NG cells receive from the olfactory bulb. As a consequence, NG cells strongly but transiently inhibit odor-evoked excitation in layer 2 principal cells, whereas HZ cells provide more diffuse and prolonged feedforward inhibition. Our findings reveal unexpected complexity in the operation of inhibition in the piriform cortex.

scholarly journals Brain state-dependent modulation of thalamic visual processing by cortico-thalamic feedback

2021 ◽  
Author(s):  
Kimberly Reinhold ◽  
Arbora Resulaj ◽  
Massimo Scanziani
Keyword(s):  
Visual Stimulus ◽  
Visual Processing ◽  
Visual Information ◽  
Early Stage ◽  
Visual Stimuli ◽  
Brain State ◽  
Spatial Features ◽  
State Dependent ◽  
Temporal And Spatial ◽  
The Brain

The behavioral state of a mammal impacts how the brain responds to visual stimuli as early as in the dorsolateral geniculate nucleus of the thalamus (dLGN), the primary relay of visual information to the cortex. A clear example of this is the markedly stronger response of dLGN neurons to higher temporal frequencies of the visual stimulus in alert as compared to quiescent animals. The dLGN receives strong feedback from the visual cortex, yet whether this feedback contributes to these state-dependent responses to visual stimuli is poorly understood. Here we show that in mice, silencing cortico-thalamic feedback abolishes state-dependent differences in the response of dLGN neurons to visual stimuli. This holds true for dLGN responses to both temporal and spatial features of the visual stimulus. These results reveal that the state-dependent shift of the response to visual stimuli in an early stage of visual processing depends on cortico-thalamic feedback.

scholarly journals Decoding the brain state-dependent relationship between pupil dynamics and resting state fMRI signal fluctuation

2021 ◽  
Author(s):  
Filip Sobczak ◽  
Patricia Pais-Roldán ◽  
Kengo Takahashi ◽  
Xin Yu
Keyword(s):  
Resting State ◽  
Pupil Diameter ◽  
Activity Patterns ◽  
Resting State Fmri ◽  
Brain State ◽  
Behavioral Experiments ◽  
Diverse Range ◽  
State Dependent ◽  
Tightly Coupled ◽  
The Brain

AbstractPupil dynamics serve as a physiological indicator of cognitive processes and arousal states of the brain across a diverse range of behavioral experiments. Pupil diameter changes reflect brain state fluctuations driven by neuromodulatory systems. Resting state fMRI (rs-fMRI) has been used to identify global patterns of neuronal correlation with pupil diameter changes, however, the linkage between distinct brain state-dependent activation patterns of neuromodulatory nuclei with pupil dynamics remains to be explored. Here, we identified four clusters of trials with unique activity patterns related to pupil diameter changes in anesthetized rat brains. Going beyond the typical rs-fMRI correlation analysis with pupil dynamics, we decomposed spatiotemporal patterns of rs-fMRI with principal components analysis (PCA) and characterized the cluster-specific pupil-fMRI relationships by optimizing the PCA component weighting via decoding methods. This work shows that pupil dynamics are tightly coupled with different neuromodulatory centers in different trials, presenting a novel PCA-based decoding method to study the brain state-dependent pupil-fMRI relationship.

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 olfactory bulb contributes to the adaptation of odor responses: the input-output transformation

2019 ◽  
Author(s):  
Douglas A. Storace ◽  
Lawrence B. Cohen
Keyword(s):  
Olfactory Bulb ◽  
Neural Mechanisms ◽  
Odorant Receptors ◽  
Nerve Terminals ◽  
Alternative Possibility ◽  
Perceptual Adaptation ◽  
Apical Dendrites ◽  
The Brain ◽  
Output Transformation ◽  
Stimulation Of

AbstractWhile humans and other animals exhibit adaptation to odorants, the neural mechanisms involved in this process are incompletely understood. One possibility is that it primarily occurs as a result of the interactions between odorants and odorant receptors expressed on the olfactory sensory neurons in the olfactory epithelium. In this scenario, adaptation would arise as a peripheral phenomenon transmitted into the brain. An alternative possibility is that adaptation occurs as a result of processing in the brain. Here we asked whether the olfactory bulb, the first stage of olfactory information processing in the brain, is involved in perceptual adaptation. Multicolor imaging was used to simultaneously measure the olfactory receptor nerve terminals (input) and mitral/tufted cell apical dendrites (output) that innervate the olfactory bulb glomerular layer. Repeated odor stimulation of the same concentration resulted in a decline in the output maps, while the input remained relatively stable. The results indicate that the mammalian olfactory bulb participates in olfactory adaptation.

scholarly journals State-dependent changes in olfactory cortical networks via cholinergic modulation

2018 ◽  
Author(s):  
Donald A. Wilson ◽  
Maxime Juventin ◽  
Maria Ilina ◽  
Alessandro Pizzo ◽  
Catia Teixeira
Keyword(s):  
Olfactory Bulb ◽  
Entorhinal Cortex ◽  
Synaptic Input ◽  
Piriform Cortex ◽  
Receptor Activation ◽  
Relative Strength ◽  
Top Down ◽  
Cortical Networks ◽  
Bottom Up ◽  
State Dependent

AbstractActivity in sensory cortical networks reflects both peripheral sensory input and intra‐ and inter-cortical network input. How sensory cortices balance these diverse inputs to provide relatively stable, accurate representations of the external world is not well understood. Furthermore, neuromodulation could alter the balance of these inputs in a state‐ and behavior-dependent manner. Here, we used optogenetic stimulation to directly assay the relative strength of bottom-up (olfactory bulb) and top-down (lateral entorhinal cortex) synaptic inputs to piriform cortex in freely moving rats. Optotrodes in the piriform cortex were used to test the relative strength of these two inputs, in separate animals, with extracellular, monosynaptic evoked potentials. The results suggest a rapid state-dependent shift in the balance of bottom-up and top-down inputs to PCX, with enhancement in the strength of lateral entorhinal cortex synaptic input and stability or depression of olfactory bulb synaptic input during slow-wave sleep compared to waking. The shift is in part due to a state-dependent change in cholinergic tone as assessed with fiber photometry of GCaMP6 fluorescence in basal forebrain ChAT+ neurons, and blockade of the state-dependent synaptic shift with cholinergic muscarinic receptor activation.

scholarly journals Decoding the brain state-dependent relationship between pupil dynamics and resting state fMRI signal fluctuation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Filip Sobczak ◽  
Patricia Pais-Roldán ◽  
Kengo Takahashi ◽  
Xin Yu
Keyword(s):  
Resting State ◽  
Pupil Diameter ◽  
Activity Patterns ◽  
Principal Component ◽  
Resting State Fmri ◽  
Brain State ◽  
Behavioral Experiments ◽  
Diverse Range ◽  
State Dependent ◽  
The Brain

Pupil dynamics serve as a physiological indicator of cognitive processes and arousal states of the brain across a diverse range of behavioral experiments. Pupil diameter changes reflect brain state fluctuations driven by neuromodulatory systems. Resting-state fMRI (rs-fMRI) has been used to identify global patterns of neuronal correlation with pupil diameter changes; however, the linkage between distinct brain state-dependent activation patterns of neuromodulatory nuclei with pupil dynamics remains to be explored. Here, we identified four clusters of trials with unique activity patterns related to pupil diameter changes in anesthetized rat brains. Going beyond the typical rs-fMRI correlation analysis with pupil dynamics, we decomposed spatiotemporal patterns of rs-fMRI with principal component analysis (PCA) and characterized the cluster-specific pupil–fMRI relationships by optimizing the PCA component weighting via decoding methods. This work shows that pupil dynamics are tightly coupled with different neuromodulatory centers in different trials, presenting a novel PCA-based decoding method to study the brain state-dependent pupil–fMRI relationship.

scholarly journals Broadly tuned and respiration-independent inhibition in the olfactory bulb of awake mice

2014 ◽  
Author(s):  
Brittany N Cazakoff ◽  
Billy Y B Lau ◽  
Kerensa L Crump ◽  
Heike Demmer ◽  
Stephen David Shea
Keyword(s):  
Olfactory Bulb ◽  
Granule Cells ◽  
Temporal Structure ◽  
Respiratory Rhythm ◽  
Brain State ◽  
Lateral Interactions ◽  
Odor Coding ◽  
State Dependent ◽  
Respiratory Synchronization ◽  
Ensemble Activity

Olfactory representations are shaped by both brain state and respiration; however, the interaction and circuit substrates of these influences are poorly understood. Granule cells (GCs) in the main olfactory bulb (MOB) are presumed to sculpt activity that reaches the olfactory cortex via inhibition of mitral/tufted cells (MTs). GCs may potentially sparsen ensemble activity by facilitating lateral inhibition among MTs, and/or they may enforce temporally-precise activity locked to breathing. Yet, the selectivity and temporal structure of GC activity during wakefulness are unknown. We recorded GCs in the MOB of anesthetized and awake mice and reveal pronounced state-dependent features of odor coding and temporal patterning. Under anesthesia, GCs exhibit sparse activity and are strongly and synchronously coupled to the respiratory cycle. Upon waking, GCs desynchronize, broaden their odor responses, and typically fire without regard for the respiratory rhythm. Thus during wakefulness, GCs exhibit stronger odor responses with less temporal structure. Based on these observations, we propose that during wakefulness GCs likely predominantly shape MT odor responses through broadened lateral interactions rather than respiratory synchronization.

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