Beyond Self-report: Brain Imaging at the Threshold of Odor Perception

Lorig, Tyler S.

doi:10.1007/s12078-012-9116-x

Cited by 13 publications

(10 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is striking that the odor‐specific piriform cortex activation was not only present in hyposmic, but also in anosmic patients. Since the anosmic patients had no functional olfactory perception based on their Sniffin’ Sticks score, the observed piriform cortex activation in anosmics might be in line with evidence that odors can alter behavior and brain activity even if they are not consciously perceived (Arzi et al, ; Lorig, ; Smeets & Dijksterhuis, ; Sobel et al, ; Zucco et al, ). This finding suggests that the pathway from the olfactory epithelium to the piriform cortex might still be intact in these patients and that the olfactory dysfunction occurs after piriform processing.…”

Section: Discussionsupporting

confidence: 67%

Severity of olfactory deficits is reflected in functional brain networks—An fMRI study

Reichert

Postma

Smeets

et al. 2018

Human Brain Mapping

View full text Add to dashboard Cite

Even though deficits in olfactory function affect a considerable part of the population, the neuronal basis of olfactory deficits remains scarcely investigated. To achieve a better understanding of how smell loss affects neural activation patterns and functional networks, we set out to investigate patients with olfactory dysfunction using functional magnetic resonance imaging (fMRI) and olfactory stimulation. We used patients' scores on a standardized olfactory test as continuous measure of olfactory function. 48 patients (mean olfactory threshold discrimination identification (TDI) score = 16.33, SD = 6.4, range 6 - 28.5) were investigated. Overall, patients showed piriform cortex activation during odor stimulation compared to pure sniffing. Group independent component analysis indicated that the recruitment of three networks during odor stimulation was correlated with olfactory function: a sensory processing network (including regions such as insula, thalamus and piriform cortex), a cerebellar network and an occipital network. Interestingly, recruitment of these networks during pure sniffing was related to olfactory function as well. Our results support previous findings that sniffing alone can activate olfactory regions. Extending this, we found that the severity of olfactory deficits is related to the extent to which neural networks are recruited both during olfactory stimulation and pure sniffing. This indicates that olfactory deficits are not only reflected in changes in specific olfactory areas but also in the recruitment of occipital and cerebellar networks. These findings pave the way for future investigations on whether characteristics of these networks might be of use for the prediction of disease prognosis or of treatment success.

show abstract

Section: Discussionsupporting

confidence: 67%

Severity of olfactory deficits is reflected in functional brain networks—An fMRI study

Reichert

Postma

Smeets

et al. 2018

Human Brain Mapping

View full text Add to dashboard Cite

show abstract

“…In this context, the present study examined the effect of inhalation of geosmin and 2-methylisoborneol on the human EEG activity in relation to brain functions. In the EEG study, delta (0-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and gamma are the most important brain waves used to understand the role of odors in the psychological and physiological conditions of humans.…”

Section: Discussionmentioning

confidence: 99%

“…Previously, several authors have used the EEG technique to determine brain wave changes during the inhalation of odor molecules [12][13][14]. It was also reported that EEG activity significantly changed in subjects who did not perceive the presence of odor molecules when compared with odor controls [15]. In addition, gender plays a major role in the detection, perception, and their cognitive implications of olfactory process with respect to different odors.…”

Section: Introductionmentioning

confidence: 99%

Gender Differences in Electroencephalographic Activity in Response to the Earthy Odorants Geosmin and 2-Methylisoborneol

et al. 2017

View full text Add to dashboard Cite

Geosmin and 2-methylisoborneol, molecules with the same odor characteristics, are mainly responsible for the smell of soil and cause odor problems worldwide in drinking water supplies. However, the effect of these odor molecules on human brain function is still unclear. The present investigation aimed to evaluate the effect of inhalation of geosmin and 2-methylisoborneol on human electroencephalographic (EEG) activity in order to understand whether their action on brain wave activity is the same or different. A total of 20 healthy volunteers (10 women and 10 men) were selected to determine the EEG power spectrum changes. The EEG data were recorded from 32 channels according to the International 10-20 system and 25 EEG power spectrum indices were analyzed. The inhalation of geosmin and 2-methylisoborneol exhibited different EEG activity by producing changes in different EEG indicators as well as brain regions. In both genders, significant changes in EEG power spectra were observed during the inhalation of geosmin when compared with 2-methylisoborneol. Absolute waves such as beta, fast alpha, low beta, high beta, and gamma significantly decreased, particularly in the centro-parietal (Cp6) region, due to the exposure to geosmin. According to gender variation, geosmin produced significant changes in the absolute low beta and high beta waves at the Cp6 region in women. In the case of 2-methylisoborneol, a significant increase in absolute alpha and absolute fast alpha activity was observed at the F8 region in men. However, there were no significant changes in absolute waves for men and women during the inhalation of geosmin and 2-methylisoborneol. Although both components are responsible for soil smell, they exhibit significantly different EEG activity according to gender.

show abstract

“…Using the electroencephalogram (EEG), similar odors perceived as identical by subjects produced very different EEG activity. It was also found that EEG activity changed in subjects who did not perceive the presence of odorants compared to odor controls (Lorig, 2012).…”

Section: Eegmentioning

confidence: 94%

“…The last type of threshold is the difference threshold, corresponding to the smallest amount by which a stimulus must be changed to make it perceptibly stronger or weaker. Lorig (2012) even discussed the existence of an unconscious effect of odors below sensory thresholds on the behavior. The French standard (AFNOR, 2012) gives a methodology for the measurement of individual thresholds on the basic tastes in water.…”

Section: Human Intrinsic Factorsmentioning

confidence: 99%

Tastes and Odors of Water—Quantifying Objective Analyses: A Review

Haese

Humeau²,

Oliveira³

et al. 2014

Critical Reviews in Environmental Science and Technology

View full text Add to dashboard Cite

Usually, organoleptic criteria have to be fulfilled for tap water in order for it to be considered safe to drink. This can be achieved at three levels: chemical analysis, sensory analysis, or through electrophysiology. While chemical analysis has been quite extensively discussed in the literature and as consumer perception is of vital importance, we propose a review of the latter two levels, namely sensory analysis and electrophysiology. We first recall some basics of perception and how it can be influenced by stimuli properties, human intrinsic factors and contextual factors, which are critical for an efficient measurement. Next, we present sensory analysis methods, as these are usually carried out in order to measure consumer appreciation of water. The drawbacks of such methods are then discussed before introducing the alternative of electrophysiological measurements. Some evidence that activity from the central and autonomic nervous systems can be measured in response to gustatory and olfactory stimuli in water is first described. Then, a review of objective physiological methods in the literature, developed to assess the emotional aspect of these reactions, is detailed. Finally, the possibility of correlating and predicting the quality, intensity, and hedonic dimension of a stimulus in water with sensory self-report and nervous system responses is discussed.

show abstract

Beyond Self-report: Brain Imaging at the Threshold of Odor Perception

Cited by 13 publications

References 39 publications

Severity of olfactory deficits is reflected in functional brain networks—An fMRI study

Severity of olfactory deficits is reflected in functional brain networks—An fMRI study

Gender Differences in Electroencephalographic Activity in Response to the Earthy Odorants Geosmin and 2-Methylisoborneol

Tastes and Odors of Water—Quantifying Objective Analyses: A Review

Contact Info

Product

Resources

About