A multimodal MR-compatible olfactometer with real-time controlling capability

Hosseini, Seyedeh Fahimeh; Kamrava, Seyed Kamran; Asadi, Somayeh; Maleki, Shayan; Zare-Sadeghi, Arash; Shakeri‐Zadeh, Ali

doi:10.1080/03091902.2020.1791987

Cited by 4 publications

(5 citation statements)

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“…Such components were used in a series of pioneering modern olfactometers in the late 1980s ( Kobal and Hummel 1988 ), and versions of these remain commercially available to this day ( Vigouroux et al 2005 ; Cohen et al 2019 ). Several groups that developed conceptually similar devices, concentrated on affordability, and on magnetic resonance imaging (MRI) compatibility ( Sobel et al 1997 ; Lorig et al 1999 ; Johnson et al 2003 ; Lowen and Lukas 2006 ; Lundström et al 2010 ; Sommer et al 2012 ; Bestgen et al 2016 ; Lowen et al 2017 ; Hosseini et al 2020 ). The latter is becoming essential, as MRI is now the primary tool for investigating function in the intact human brain, and to investigate olfactory function, we need MRI-compatible olfactometers.…”

Section: Introductionmentioning

confidence: 99%

Odor Canopy: A Method for Comfortable Odorant Delivery in MRI

et al. 2021

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Functional magnetic resonance imaging (fMRI) has become the leading method for measuring the human brain response to sensory stimuli. However, olfaction fMRI lags behind vision and audition fMRI for two primary reasons: First, the olfactory brain areas are particularly susceptible to imaging artefacts, and second, the olfactory stimulus is particularly difficult to control in the fMRI environment. A component of the latter is related to the odorant-delivery human-machine interface, namely the point where odorants exit the dispensing apparatus to reach at the nose. Previous approaches relied on either nasal cannulas or nasal masks, each associated with particular drawbacks and discomforts. Here we provide detailed descriptions and instructions for transforming the MRI head-coil into an olfactory microenvironment, or odor canopy, where odorants can be switched on and off in less than 150 milliseconds without cannula or mask. In a proof-of-concept experiment we demonstrate that odor canopy provides for clearly dissociable odorant presence and absence, with no non-olfactory cues. Moreover, we find that odor canopy is rated more comfortable than nasal-mask, and we demonstrate that using odor canopy in the fMRI generates a typical olfactory brain-response. We conclude in recommending this approach for minimized discomfort in fMRI of olfaction.

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Section: Introductionmentioning

confidence: 99%

Odor Canopy: A Method for Comfortable Odorant Delivery in MRI

et al. 2021

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“…Olfactory stimulation was performed using a hand-made multimodal MR-compatible olfactometer. 23 Functional images were subsequently obtained in a block-design task consisting of two odor exposure blocks (on-period) and two normal breathing blocks (off-period). Two samples of odor (vanillin and rose) during 10 s on-periods, each followed by 30 s of odorless air during the off-period, with continuous air flow (30 L/min) were delivered to both nostrils through a nasal mask placed at the end of a silicon air path.…”

Section: Methodsmentioning

confidence: 99%

“…21 Functional changes and effective connectivity networks in these patients after olfactory training have been also demonstrated in previous studies. 17,22,23…”

Section: Introductionmentioning

confidence: 99%

“…21 Functional changes and effective connectivity networks in these patients after olfactory training have been also demonstrated in previous studies. 17,22,23 In recent years, LLLT, known as photobiomodulation (PBM), firstly used in the 1980s, has been already the subject of numerous recent studies; especially in the areas of physical medicine and rehabilitation, as it revealed an immediate protective effect, reducing the formation of edema and scar tissue in the region of injury and increasing axonal metabolism. 24,25 In addition, it has anti-inflammatory properties and increases mitotic activity, resulting in a speedy nerve regeneration process in peripheral nerves repaired by surgery.…”

Section: Introductionmentioning

confidence: 99%

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The brain functional connectivity alterations in traumatic patients with olfactory disorder after low-level laser therapy demonstrated by fMRI

et al. 2023

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Background Low-level laser therapy (LLLT) has been clinically accepted to accelerate the nerve regeneration process after a nerve injury or transection. We aimed to investigate the neuronal basis and the influence of LLLT on brain functional networks in traumatic patients with olfactory dysfunction. Methods Twenty-four Patients with traumatic anosmia/hyposmia were exposed to pleasant olfactory stimuli during a block-designed fMRI session. After a 10-week period, patients as control group and patients who had completed the sessions of LLLT were invited for follow-up testing using the same fMRI protocol. Two-sample t-tests were conducted to explore group differences in activation responding to odorants ( p-FDR-corrected <0.05). Differences of functional connectivity were compared between the two groups and the topological features of the olfactory network were calculated. Correlation analysis was performed between graph parameters and TDI score. Results Compared to controls, laser-treated patients showed increased activation in the cingulate, rectus gyrus, and some parts of the frontal gyrus. Shorter pathlength ( p = 0.047) and increased local efficiency ( p = 0.043) within the olfactory network, as well as decreased inter-network connectivity within the whole brain were observed in patients after laser surgery. Moreover, higher clustering and local efficiency were related to higher TDI score, as manifested in increased sensitivity to identify odors. Conclusions The results support that low-level laser induces neural reorganization process and make new connections in the olfactory structures. Furthermore, the connectivity parameters may serve as potential biomarkers for traumatic anosmia or hyposmia by revealing the underlying neural mechanisms of LLLT.

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“…Olfactory disorders have extensive impacts on the lives of patients and can cause serious problems (Croy et al, 2014;Hosseini et al, 2020). Head trauma is one of the major causes of olfactory malfunctions (Howell et al, 2018) and many people lose their olfaction due to head trauma related to accidents every day (Croy et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effects of olfactory training on resting-state effective connectivity in patients with posttraumatic olfactory dysfunction

Hosseini¹,

Zare-Sadeghi²,

Sadigh-Eteghad³

et al. 2020

Acta Neurobiologiae Experimentalis

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The present study investigated if and how the smell training scheme affects resting-state effective connectivity. We focused on connectivity among brain regions that participate in olfactory-related processes, including the piriform cortex, amygdala, orbitofrontal cortex (OFC), insula, and cingulate cortex. Sixteen patients with posttraumatic olfactory dysfunctions between the ages of 18 and 36 years participated in this study. Olfactory performance of subjects was evaluated using the Sniffin' Sticks test kit and then, resting-state functional magnetic resonance imaging (fMRI) was performed. Of the 16 participants, 8 underwent olfactory training for 16 weeks and the remaining 8 did not receive the treatment (the control group). After 16 weeks, participants in both groups underwent the same procedure (smell testing and the MRI examination). Olfactory performance scores were compared between groups using an independent samples t-test. Spectral dynamic causal modeling was applied to resting-state fMRI data to identify alterations in effective connectivity due to the smell training. We found that patients in the treatment group improved in the odor discrimination task and overall olfactory function as compared to the control group. Compared to the control group, patients in the treatment group had increased self-inhibitory connectivity of the OFC and increased excitatory connectivity from the cingulate cortex to the insula. Moreover, the excitatory connectivity from the OFC to the cingulate cortex was found to be weaker following the olfactory training scheme. This study shows that a smell training scheme can cause changes in resting-state effective connectivity parameters that can be attributed to improvements in the odor discrimination task.

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A multimodal MR-compatible olfactometer with real-time controlling capability

Cited by 4 publications

References 38 publications

Odor Canopy: A Method for Comfortable Odorant Delivery in MRI

Odor Canopy: A Method for Comfortable Odorant Delivery in MRI

The brain functional connectivity alterations in traumatic patients with olfactory disorder after low-level laser therapy demonstrated by fMRI

Effects of olfactory training on resting-state effective connectivity in patients with posttraumatic olfactory dysfunction

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