Salamander olfactory bulb neuronal activity observed by video rate, voltage-sensitive dye imaging. III. Spatial and temporal properties of responses evoked by odorant stimulation

1995 ◽  
Vol 73 (5) ◽  
pp. 2053-2071 ◽  
Author(s):  
A. R. Cinelli ◽  
K. A. Hamilton ◽  
J. S. Kauer
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Time Course ◽  
Odorant Receptor ◽  
Activity Patterns ◽  
Response Patterns ◽  
Voltage Sensitive Dye ◽  
Odor Coding ◽  
Temporal Properties ◽  
Spatial And Temporal Distributions

1. Activity patterns across and within the laminae of the olfactory bulb were analyzed by imaging voltage-sensitive dye responses during odorant stimulation of all or part of the ventral olfactory mucosa. 2. The time course of the signals was generally characterized by a brief, small hyperpolarization, followed by a period of depolarization, and then a longer-lasting hyperpolarization similar to that seen with electric stimulation but with longer durations. 3. The activity was distributed nonhomogeneously across the bulbar laminae in the form of spatially segregated clusters having bandlike appearances. Clusters were observed with three monomolecular odorants, amyl acetate, ethyl-n-butyrate, and limonene, and with the complex odor of meal worms. Although response patterns to different odorants overlapped, they also showed differences in overall distribution. 4. Delivery of high odorant concentrations increased the size of the activated areas and accentuated the degree of response pattern overlap among different odorants. The general properties of the response patterns generated by each odorant were, however, similar at different odorant concentrations and in each of the animals tested. 5. The spatial and temporal distributions of the bulbar responses were somewhat similar regardless of whether the odorants were applied to local epithelial regions via punctate stimulation or to the entire mucosa. Certain regions did, however, have lower thresholds than others for eliciting bulbar activity in response to particular odorants. 6. Odorants applied to regions of the epithelium outside the areas of maximum sensitivity elicited odorant-related activity patterns with depolarizing and hyperpolarizing components similar to those seen with overall stimulation, but only if higher concentrations were used. Activation of distributed odorant sensitivities presumably gave rise to these patterns. 7. These data suggest that subsets of odorant receptor types are found in different areas of the olfactory epithelium, and demonstrate that there is widespread distribution across the epithelium of receptors sensitive to particular odorants. On the basis of the structure of these epithelial fields and the bulb response patterns that they relate to, these findings also provide evidence for complex spatial relationships between the olfactory epithelium and bulb. 8. The findings from this study suggest that representation of odor information in the salamander olfactory bulb does not occur by activation of a few selective bulbar regions, each related to a different odorant species. Instead, large regions of bulbar circuitry are involved in which molecular epitopes may be the unit of representation. Incorporation of new data presented here into a hypothesis of odor coding is discussed.

The recording of odorant-induced mucosal activity patterns with a voltage-sensitive dye

1992 ◽  
Vol 68 (5) ◽  
pp. 1804-1819 ◽  
Author(s):  
P. F. Kent ◽  
M. M. Mozell
Keyword(s):  
Time Course ◽  
Activity Patterns ◽  
Temporal Patterns ◽  
Amyl Acetate ◽  
Response Magnitude ◽  
Voltage Sensitive Dye ◽  
Pixel Array ◽  
The Times ◽  
Humidified Air ◽  
Triton X

1. Fluorescence changes in the dye (WW 781) were monitored at 100 contiguous sites in a 10 x 10-pixel array on the bullfrog and salamander olfactory mucosas every 10 ms in response to odorous stimuli. The odorants were d-limonene, butanol, and amyl acetate, each presented at two concentrations with a 3:1 ratio. 2. The fluorescence signals elicited by these odorous stimuli were nearly identical in shape and time course to the electro-olfactograms (EOGs) recorded from the same animal under identical conditions. Like the EOGs, the fluorescence signals exhibited adaptation and were abolished by both Triton X-100 and ether. There was no measurable fluorescence when the tissue was not stained with the dye, and there was no change in fluorescence when, for stained tissue, nonodorized, humidified air was presented as the stimulus. 3. This technique presumably monitors the same events as the EOG, but has the advantage of simultaneously recording the odorant-induced activity from multiple sites across most of the mucosa. Thus this technique preserves subtle differences heretofore lost by other techniques both in the coarseness of their matrices and in the variability generated by trying to piece together, into one collage, results from numerous presentations given at different times. 4. In all preparations, there was a larger difference in the inherent activity patterns (derived from response magnitudes) between different odorants than between different concentrations of the same odorant. These differences were largest on the mucosa lining the floor of salamander's olfactory sac. d-limonene and butanol gave their largest responses near the internal and external nares, respectively, whereas the responses for amyl acetate were more uniform across the mucosal sheet. In contrast to the salamander, smaller differences were observed for both the roof and the floor of the bullfrog's olfactory sac. For the floor, both amyl acetate and d-limonene elicited similar patterns of response magnitude, whereas butanol differed from each of these odorants by eliciting a larger response on the anteriolateral aspect of the mucosa and a lesser response on the remainder. For the roof, different odorants produced different activity patterns, which had profiles not simply described as regions of maximal and minimal responsiveness. 5. Different inherent activity patterns based on temporal characteristics of the fluorescence responses were also observed for different odorants. Each odorant produced a different pixel-by-pixel pattern for the times at which the responses started and ended. For any given odorant, these temporal patterns paralleled the patterns given by response magnitudes.(ABSTRACT TRUNCATED AT 400 WORDS)

Relationships Between Odor-Elicited Oscillations in the Salamander Olfactory Epithelium and Olfactory Bulb

2000 ◽  
Vol 83 (2) ◽  
pp. 754-765 ◽  
Author(s):  
Kathleen M. Dorries ◽  
John S. Kauer
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Time Course ◽  
Saturated Vapor ◽  
Peak Frequency ◽  
Amyl Acetate ◽  
Ambystoma Tigrinum ◽  
Common Source ◽  
Population Activity ◽  
Central Processing

Oscillations in neuronal population activity, or the synchronous neuronal spiking that underlies them, are thought to play a functional role in sensory processing in the CNS. In the olfactory system, stimulus-induced oscillations are observed both in central processing areas and in the peripheral receptor epithelium. To examine the relationship between these peripheral and central oscillations, we recorded local field potentials simultaneously from the olfactory epithelium and olfactory bulb in tiger salamanders ( Ambystoma tigrinum). Stimulus-induced oscillations recorded at these two sites were matched in frequency and slowed concurrently over the time course of the response, suggesting that the oscillations share a common source or are modulated together. Both the power and duration of oscillations increased over a range of amyl acetate concentrations from 2.5 × 10−2 to 1 × 10−1 dilution of saturated vapor, but peak frequency was not affected. The frequency of the oscillation did vary with different odorant compounds in both olfactory epithelium and bulb (OE and OB): amyl acetate, ethyl fenchol and d-carvone elicited oscillations of significantly different frequencies, and there was no difference in OE and OB oscillation frequencies. No change in the power or frequency of OE oscillations was observed after sectioning the olfactory nerve, indicating that the OE oscillations have a peripheral source. Finally, application of 1.0 and 10 μM tetrodotoxin to the epithelium blocked OE oscillations in a dose-dependent and reversible manner, suggesting that peripheral olfactory oscillations are related to receptor neuron spiking.

Neurogenesis in olfactory epithelium: loss and recovery of transepithelial voltage transients following olfactory nerve section

1981 ◽  
Vol 45 (3) ◽  
pp. 516-528 ◽  
Author(s):  
P. A. Simmons ◽  
T. V. Getchell
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Time Course ◽  
Olfactory Nerve ◽  
Nerve Section ◽  
Retrograde Degeneration ◽  
Transepithelial Voltage ◽  
Receptor Neurons ◽  
Voltage Transients

1. Unilateral olfactory nerve section was performed on the salamander, Ambystoma tigrinum. Physiological recordings and macroscopic observations were made to investigate the physiological correlates of functional recovery in the olfactory epithelium. 2. Slow transepithelial voltage transients, Veog, evoked by several odorous stimuli systematically decreased in amplitude during the initial 7 days and were not recorded at 10 days following nerve section, suggesting retrograde degeneration of receptor neurons. This was true for negative Veog(-), and positive, Veog(+), response components. Responses obtained from the untreated contralateral side of each animal remained similar to nonaxotomized controls. 3. Progressive recovery of the voltage transients was studied at 24, 45, 80, and 100 days following nerve section. At all stages of recovery, the wave form and time course of the responses were characteristic for each stimulus. This suggested that the response properties of the newly differentiated neuronal population were similar to those of the mature population. 4. At 100 days, response amplitudes evoked by all stimuli were similar to control values at all recording sites on the epithelial surface. The simultaneous loss and recovery of positive and negative components of the Veog indicated that the sources of both are dependent on the presence of functionally mature olfactory receptor neurons. 5. Visual inspection indicated that the olfactory nerve was reconstituted and reconnected to the olfactory bulb between 30-60 days following transection. The fact that physiological activity was recorded in the epithelium prior to this event suggests that molecular recognition and sensory transduction are not dependent on connectivity with the olfactory bulb. 6. It is concluded that physiological recovery of the olfactory receptor cell population occurs following axotomy. The time course of recovery was consistent with morphological evidence (see Ref. 57), indicating that newly differentiated receptor neurons are derived from cells in the basal region of the epithelium and replace the population lost through retrograde degeneration.

Synchronized Oscillatory Discharges of Mitral/Tufted Cells With Different Molecular Receptive Ranges in the Rabbit Olfactory Bulb

1999 ◽  
Vol 82 (4) ◽  
pp. 1786-1792 ◽  
Author(s):  
Hideki Kashiwadani ◽  
Yasnory F. Sasaki ◽  
Naoshige Uchida ◽  
Kensaku Mori
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Local Field ◽  
Odorant Receptor ◽  
Field Potential ◽  
Neuronal Circuit ◽  
Cross Correlation Analysis ◽  
Different Types ◽  
Tufted Cells ◽  
Unit Spike

Individual glomeruli in the mammalian olfactory bulb represent a single or a few type(s) of odorant receptors. Signals from different types of receptors are thus sorted out into different glomeruli. How does the neuronal circuit in the olfactory bulb contribute to the combination and integration of signals received by different glomeruli? Here we examined electrophysiologically whether there were functional interactions between mitral/tufted cells associated with different glomeruli in the rabbit olfactory bulb. First, we made simultaneous recordings of extracellular single-unit spike responses of mitral/tufted cells and oscillatory local field potentials in the dorsomedial fatty acid–responsive region of the olfactory bulb in urethan-anesthetized rabbits. Using periodic artificial inhalation, the olfactory epithelium was stimulated with a homologous series of n-fatty acids or n-aliphatic aldehydes. The odor-evoked spike discharges of mitral/tufted cells tended to phase-lock to the oscillatory local field potential, suggesting that spike discharges of many cells occur synchronously during odor stimulation. We then made simultaneous recordings of spike discharges from pairs of mitral/tufted cells located 300–500 μm apart and performed a cross-correlation analysis of their spike responses to odor stimulation. In ∼27% of cell pairs examined, two cells with distinct molecular receptive ranges showed synchronized oscillatory discharges when olfactory epithelium was stimulated with one or a mixture of odorant(s) effective in activating both. The results suggest that the neuronal circuit in the olfactory bulb causes synchronized spike discharges of specific pairs of mitral/tufted cells associated with different glomeruli and the synchronization of odor-evoked spike discharges may contribute to the temporal binding of signals derived from different types of odorant receptor.

scholarly journals Odor coding in the mammalian olfactory epithelium

2021 ◽  
Author(s):  
Smija M. Kurian ◽  
Rafaella G. Naressi ◽  
Diogo Manoel ◽  
Ann-Sophie Barwich ◽  
Bettina Malnic ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Olfactory Epithelium ◽  
New Technologies ◽  
Odorant Receptor ◽  
Olfactory Mucosa ◽  
Odorant Receptors ◽  
Odor Coding ◽  
New Era ◽  
Odor Detection ◽  
Receptor Interactions

AbstractNoses are extremely sophisticated chemical detectors allowing animals to use scents to interpret and navigate their environments. Odor detection starts with the activation of odorant receptors (ORs), expressed in mature olfactory sensory neurons (OSNs) populating the olfactory mucosa. Different odorants, or different concentrations of the same odorant, activate unique ensembles of ORs. This mechanism of combinatorial receptor coding provided a possible explanation as to why different odorants are perceived as having distinct odors. Aided by new technologies, several recent studies have found that antagonist interactions also play an important role in the formation of the combinatorial receptor code. These findings mark the start of a new era in the study of odorant-receptor interactions and add a new level of complexity to odor coding in mammals.

scholarly journals Odor Coding in the Mammalian Olfactory Epithelium

2020 ◽  
Author(s):  
Smija M. Kurian ◽  
Rafaella G. Naressi ◽  
Diogo Manoel ◽  
Ann-Sophie Barwich ◽  
Bettina Malnic ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Olfactory Epithelium ◽  
New Technologies ◽  
Odorant Receptor ◽  
Olfactory Mucosa ◽  
Odorant Receptors ◽  
Odor Coding ◽  
New Era ◽  
Odor Detection ◽  
Receptor Interactions

Noses are extremely sophisticated chemical detectors allowing animals to use scents to interpret and navigate their environments. Odor detection starts with the activation of odorant receptors (ORs), expressed in mature olfactory sensory neurons (OSNs) populating the olfactory mucosa. Different odorants, or different concentrations of the same odorant, activate unique ensembles of ORs. This mechanism of combinatorial receptor coding provided a possible explanation as to why different odorants are perceived as having distinct odors. Aided by new technologies, several recent studies have found that antagonist interactions also play an important role in the formation of the combinatorial receptor code. These findings mark the start of a new era in the study of odorant-receptor interactions and add a new level of complexity to odor coding in mammals.

scholarly journals Olfactory Optogenetics: Light Illuminates the Chemical Sensing Mechanisms of Biological Olfactory Systems

Biosensors ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 309
Author(s):  
Ping Zhu ◽  
Yulan Tian ◽  
Yating Chen ◽  
Wei Chen ◽  
Ping Wang ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Olfactory System ◽  
Chemical Sensing ◽  
Sensory Input ◽  
Activity Patterns ◽  
Neuron Activity ◽  
Technical Approach ◽  
Odor Coding ◽  
Olfactory Systems ◽  
Specific Part

The mammalian olfactory system has an amazing ability to distinguish thousands of odorant molecules at the trace level. Scientists have made great achievements on revealing the olfactory sensing mechanisms in decades; even though many issues need addressing. Optogenetics provides a novel technical approach to solve this dilemma by utilizing light to illuminate specific part of the olfactory system; which can be used in all corners of the olfactory system for revealing the olfactory mechanism. This article reviews the most recent advances in olfactory optogenetics devoted to elucidate the mechanisms of chemical sensing. It thus attempts to introduce olfactory optogenetics according to the structure of the olfactory system. It mainly includes the following aspects: the sensory input from the olfactory epithelium to the olfactory bulb; the influences of the olfactory bulb (OB) neuron activity patterns on olfactory perception; the regulation between the olfactory cortex and the olfactory bulb; and the neuromodulation participating in odor coding by dominating the olfactory bulb. Finally; current challenges and future development trends of olfactory optogenetics are proposed and discussed.

Salamander olfactory bulb neuronal activity observed by video rate, voltage-sensitive dye imaging. II. Spatial and temporal properties of responses evoked by electric stimulation

1995 ◽  
Vol 73 (5) ◽  
pp. 2033-2052 ◽  
Author(s):  
A. R. Cinelli ◽  
J. S. Kauer
Keyword(s):  
Olfactory Bulb ◽  
Electric Stimulation ◽  
Plexiform Layer ◽  
Short Latency ◽  
Voltage Sensitive Dye ◽  
Glomerular Layer ◽  
Temporal Properties ◽  
Optical Responses ◽  
Stimulation Of

1. Video imaging of changes in voltage-sensitive dye (VSD) fluorescence was used to analyze spatial and temporal properties of activity patterns in the in vivo salamander olfactory bulb and primordium piriform cortex after electric stimulation. Distribution of activity among and within the neuronal layers was analyzed after orthodromic stimulation of the whole olfactory nerve (ON), isolated fascicles, or local epithelial sites, and after antidromic stimulation of the medial olfactory tract (OT). 2. Optical signals propagated through the bulbar layers with a sequence that correlates with electrophysiological responses. After orthodromic stimulation, VSD responses started in the glomerular layer, spread to the deeper laminae, and, after reaching the region of mitral/tufted somata, were observed as a brief burst of activity in the OT. Compound action potentials in the ON were associated with short-duration, rapidly depolarizing optical responses in the ON layer. Responses in glomerular layer and external plexiform layer (EPL) first showed in some recordings a brief, small-amplitude hyperpolarization, followed by a period of depolarization, followed by a second, longer-lasting hyperpolarization. The periods of optical hyperpolarization could be related to events observed in intracellular mitral/tufted cell recordings. 3. With shocks delivered to the entire ON, depolarizing responses were nonhomogeneously distributed, appearing as multiple foci or bands of activity. Spatial patterns within each bulbar layer had poorly defined borders. Sites showing short-latency responses were often those with the largest and longest-lasting activity. 4. Increasing the intensity of stimulation to the ON enhanced the size and duration of the depolarizing and hyperpolarizing responses. The short-latency, early hyperpolarization was best seen with low-intensity, peripherally placed stimuli. 5. ON stimulation also elicited activity in the contralateral bulb. Activity started at the innermost layers and spread in patches to regions of the EPL just beneath the glomeruli. These had durations similar to ipsilateral responses, but longer latencies. A period of early hyperpolarization, longer than that on the ipsilateral side, was followed by prolonged depolarization and then by a second, later hyperpolarization. 6. Antidromic stimuli applied to the OT evoked optical responses consisting of a period of depolarization followed by hyperpolarization, similar to the components elicited by orthodromic stimuli. These responses had short time courses, began in the deeper layers, and spread to the superficial region of the bulb usually without reaching the glomerular region. 7. Punctate stimulation of the mucosa or nerve elicited depolarizing and hyperpolarizing events that depended on the stimulation site.(ABSTRACT TRUNCATED AT 400 WORDS)

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