Electrophysiological recordings from the olfactory epithelium and human brain in response to stimulation with HLA related peptides

Author(s):  
Marie-Elisabeth Lessmann ◽  
Cagdas Guducu ◽  
Bergoi Ibarlucea ◽  
Thomas Hummel
1994 ◽  
Vol 71 (1) ◽  
pp. 150-160 ◽  
Author(s):  
A. Mackay-Sim ◽  
S. Kesteven

1. Regional differences in odorant-induced responsiveness of the rat olfactory epithelium were measured via electrophysiological recordings [negative component of electro-olfactogram (Veog(-)) made from the surface of the olfactory epithelium on the nasal septum]. The nasal septum provided a flat surface from which multiple recordings could be made. 2. Veog(-)s were recorded from a standardized grid of 16 sites. This grid of recording sites extended over most of the surface of the olfactory epithelium on the nasal septum. 3. Twenty-one animals were tested for their responses to seven odorants. The animals were divided into three groups, each of which was tested with two different odorants plus amyl acetate, which provided a comparison between the groups. 4. For each odorant in each animal, topographic maps of relative responsiveness were derived to test whether odorants elicited different patterns of responses in the same individual. Topographic maps of responsiveness were derived also for the animal groups to test for the generality of the form of the maps for different odorants. Response latencies were also measured for each odorant at each recording site. 5. All individuals showed different topographic patterns of responses to the three test odorants. For most odorants, the location of the most responsive site was similar in all animals. In different animals the topographic maps for the same odorant were remarkably similar. Topographic maps for the odorants were all different from one another. 6. These results are consistent with the hypothesis that odorant quality is encoded in the differential spatial distribution of receptor cells whose differences in responsiveness appear to be distributed as a continuum across the epithelium. The results establish for a mammalian species what was previously reported in amphibians. These differences are presumed to be due to differential expression of odorant receptor proteins. 7. The mean response latency was 32 ms. This period was similar for all odorants, all animals, and all recording sites and was independent of Veog(-) amplitude. It is concluded that diffusion through the mucus contributed approximately 6 ms to the latency of onset of the responses to these odorants.


2021 ◽  
Author(s):  
Francesca M. Barbero ◽  
Roberta P. Calce ◽  
Siddharth Talwar ◽  
Bruno Rossion ◽  
Olivier Collignon

AbstractVoices are arguably among the most relevant sounds in humans’ everyday life, and several studies have suggested the existence of voice-selective regions in the human brain. Despite two decades of research, defining the human brain regions supporting voice recognition remains challenging. Moreover, whether neural selectivity to voices is merely driven by acoustic properties specific to human voices (e.g. spectrogram, harmonicity), or whether it also reflects a higher-level categorization response is still under debate. Here, we objectively measured rapid automatic categorization responses to human voices with Fast Periodic Auditory Stimulation (FPAS) combined with electroencephalography (EEG). Participants were tested with stimulation sequences containing heterogeneous non-vocal sounds from different categories presented at 4 Hz (i.e., 4 stimuli/second), with vocal sounds appearing every 3 stimuli (1.333 Hz). A few minutes of stimulation are sufficient to elicit robust 1.333 Hz voice-selective focal brain responses over superior temporal regions of individual participants. This response is virtually absent for sequences using frequency-scrambled sounds, but is clearly observed when voices are presented among sounds from musical instruments matched for pitch and harmonicity-to-noise ratio. Overall, our FPAS paradigm demonstrates that the human brain seamlessly categorizes human voices when compared to other sounds including matched musical instruments and that voice-selective responses are at least partially independent from low-level acoustic features, making it a powerful and versatile tool to understand human auditory categorization in general.Significance statementVoices are arguably among the most relevant sounds we hear in our everyday life, and several studies have corroborated the existence of regions in the human brain that respond preferentially to voices. However, whether this preference is driven by specific acoustic properties of voices or if it rather reflects a higher-level categorization response to voices is still under debate. We propose a new approach to objectively identify rapid automatic voice-selective responses with frequency tagging and electroencephalographic recordings. In four minutes of recording only, we recorded robust voice-selective responses independent from low-level acoustic cues, making this approach highly promising for studying auditory perception in children and clinical populations.


Author(s):  
Coralie Mignot ◽  
Anica Schunke ◽  
Charlotte Sinding ◽  
Thomas Hummel

Abstract Purpose Olfactory adaptation is a peripheral (at the epithelium level) or a central (at the brain level) mechanism resulting from repeated or prolonged odorous exposure that can induce a perceptual decrease. The aim of this study was to assess whether a peripheral adaptation occurs when an odor is repeated ten times. Moreover, the specificity of the peripheral adaptation to the nature of the odorant was investigated. Methods Four odorants (eugenol, manzanate, ISO E Super and phenylethanol) were presented using precisely controlled air-dilution olfactometry. They differed in terms of their physicochemical properties. Electrophysiological recordings were made at the level of the olfactory mucosa, the so-called electro-olfactogram (EOG). Thirty-five right-handed participants were recruited. Results Sixty-nine percent of the participants presented at least one EOG, whatever the odor condition. The EOG amplitude did not significantly decrease over 10 repeated exposures to any odorant. The intensity ratings tended to decrease over stimulations for manzanate, PEA, and eugenol. No correlation was found between the mean EOG amplitudes and the mean intensity ratings. However, the presence of EOG amplitude decreases over stimulations for few subjects suggests that peripheral adaptation might exist. Conclusion Overall, our results did not establish a clear peripheral adaptation measured with EOG but indicate the eventuality of such an effect.


2016 ◽  
Vol 39 ◽  
Author(s):  
Giosuè Baggio ◽  
Carmelo M. Vicario

AbstractWe agree with Christiansen & Chater (C&C) that language processing and acquisition are tightly constrained by the limits of sensory and memory systems. However, the human brain supports a range of cognitive functions that mitigate the effects of information processing bottlenecks. The language system is partly organised around these moderating factors, not just around restrictions on storage and computation.


Author(s):  
Bert Ph. M. Menco ◽  
Ido F. Menco ◽  
Frans L.T. Verdonk

Previously we presented an extensive study of the distributions of intramembranous particles of structures in apical surfaces of nasal olfactory and respiratory epithelia of the Sprague-Dawley rat. For the same structures these distributions were compared in samples which were i) chemically fixed and cryo-protected with glycerol before cryo-fixation, after excision, and ii)ultra-rapidly frozen by means of the slam-freezing method. Since a three-dimensional presentation markedly improves visualization of structural features micrographs were presented as stereopairs. Two exposures were made by tiling the sample stage of the electron microscope 6° in either direction with an eucentric goniometer. The negatives (Agfa Pan 25 Professional) were reversed with Kodak Technical Pan Film 2415 developed in D76 1:1. The prints were made from these reversed negatives. As an example tight-junctional features of an olfactory supporting cell in a region where this cell conjoined with two other cells are presented (Fig. 1).


Author(s):  
K.S. Kosik ◽  
L.K. Duffy ◽  
S. Bakalis ◽  
C. Abraham ◽  
D.J. Selkoe

The major structural lesions of the human brain during aging and in Alzheimer disease (AD) are the neurofibrillary tangles (NFT) and the senile (neuritic) plaque. Although these fibrous alterations have been recognized by light microscopists for almost a century, detailed biochemical and morphological analysis of the lesions has been undertaken only recently. Because the intraneuronal deposits in the NFT and the plaque neurites and the extraneuronal amyloid cores of the plaques have a filamentous ultrastructure, the neuronal cytoskeleton has played a prominent role in most pathogenetic hypotheses.The approach of our laboratory toward elucidating the origin of plaques and tangles in AD has been two-fold: the use of analytical protein chemistry to purify and then characterize the pathological fibers comprising the tangles and plaques, and the use of certain monoclonal antibodies to neuronal cytoskeletal proteins that, despite high specificity, cross-react with NFT and thus implicate epitopes of these proteins as constituents of the tangles.


Author(s):  
C. S. Potter ◽  
C. D. Gregory ◽  
H. D. Morris ◽  
Z.-P. Liang ◽  
P. C. Lauterbur

Over the past few years, several laboratories have demonstrated that changes in local neuronal activity associated with human brain function can be detected by magnetic resonance imaging and spectroscopy. Using these methods, the effects of sensory and motor stimulation have been observed and cognitive studies have begun. These new methods promise to make possible even more rapid and extensive studies of brain organization and responses than those now in use, such as positron emission tomography.Human brain studies are enormously complex. Signal changes on the order of a few percent must be detected against the background of the complex 3D anatomy of the human brain. Today, most functional MR experiments are performed using several 2D slice images acquired at each time step or stimulation condition of the experimental protocol. It is generally believed that true 3D experiments must be performed for many cognitive experiments. To provide adequate resolution, this requires that data must be acquired faster and/or more efficiently to support 3D functional analysis.


2019 ◽  
Vol 28 (1) ◽  
pp. 114-124
Author(s):  
Linda W. Norrix ◽  
Julie Thein ◽  
David Velenovsky

Purpose Low residual noise (RN) levels are critically important when obtaining electrophysiological recordings of threshold auditory brainstem responses. In this study, we examine the effectiveness and efficiency of Kalman-weighted averaging (KWA) implemented on the Vivosonic Integrity System and artifact rejection (AR) implemented on the Intelligent Hearing Systems SmartEP system for obtaining low RN levels. Method Sixteen adults participated. Electrophysiological measures were obtained using simultaneous recordings by the Vivosonic and Intelligent Hearing Systems for subjects in 2 relaxed conditions and 4 active motor conditions. Three averaging times were used for the relaxed states (1, 1.5, and 3 min) and for the active states (1.5, 3, and 6 min). Repeated-measures analyses of variance were used to examine RN levels as a function of noise reduction strategy (i.e., KWA, AR) and averaging time. Results Lower RN levels were obtained using KWA than AR in both the relaxed and active motor states. Thus, KWA was more effective than was AR under the conditions examined in this study. Using KWA, approximately 3 min of averaging was needed in the relaxed condition to obtain an average RN level of 0.025 μV. In contrast, in the active motor conditions, approximately 6 min of averaging was required using KWA. Mean RN levels of 0.025 μV were not attained using AR. Conclusions When patients are not physiologically quiet, low RN levels are more likely to be obtained and more efficiently obtained using KWA than AR. However, even when using KWA, in active motor states, 6 min of averaging or more may be required to obtain threshold responses. Averaging time needed and whether a low RN level can be attained will depend on the level of motor activity exhibited by the patient.


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