Migraine with aura: less control over pain and fragrances?

Responses to the activation of different intranasal trigeminal receptors: Evidence from behavioral, peripheral and central levels

AIM

There are various receptors that mediate intranasal trigeminal sensations. However, few studies compare the response patterns across different receptor activations.

METHODS

We recorded negative mucosal potentials (NMPs) in 24 healthy participants and event-related potentials (ERPs) in 17 participants during exposure to five odors that trigger trigeminal sensations and one olfactory stimulus. Additionally, 10 participants completed a continuous odor intensity rating task.

RESULTS

We observed a significant effect of odor type on NMP amplitudes (F=13.51-21.88, p's < 0.01), with cyclohexanone (TRPV1) and CO2 (TRPV1 +A1) inducing greater N1 and/or P1N1 amplitudes than other stimuli (t = 3.28-7.54, p's < 0.05). Similar differences were seen in ERP amplitudes (F=3.69-12.25, p's < 0.05), with cyclohexanone showing greater P2 and/or N1P2 amplitudes than PEA (odorant), carvacrol (TRPV3 +A1), and perillaldehyde (TRPA1) (t = 3.13-4.10, p's < 0.05). CO2 also produced greater amplitudes than carvacrol (t = 3.53-4.42, p's < 0.05). In the odor intensity rating task, cyclohexanone, CO2, and isopulegol (TRPM8 +TRPA1) had higher peak ratings, steeper slopes, and/or shorter latencies (F=6.15-13.86, p's < 0.01; t = 3.14-7.76, p's < 0.05).

CONCLUSIONS

Activation of different intranasal trigeminal receptors yields varied responses. Notably, stimuli involving TRPV1 activation, linked to irritation or pain, elicited stronger behavioral and neural activity compared to stimuli involving other receptors, even when controlling for rated stimulus intensity. This emphasizes TRPV1's significance in survival adaptation. Future studies should test different sets of stimulants to verify the robustness of these findings.

Effects of Emotional Olfactory Stimuli on Modulating Angry Driving Based on an EEG Connectivity Study

Effectively regulating anger driving has become critical in ensuring road safety. The existing research lacks a feasible exploration of anger-driving regulation. This paper delves into the effect and neural mechanisms of emotional olfactory stimuli (EOS) on regulating anger driving based on EEG. First, this study designed an angry driving regulation experiment based on EOS to record EEG signals. Second, brain activation patterns under various EOS conditions are explored by analyzing functional brain networks (FBNs). Additionally, the paper analyzes dynamic alterations in anger-related characteristics to explore the intensity and persistence of regulating anger driving under different EOS. Finally, the paper studies the frequency energy of EEG changes under EOS through time-frequency analysis. The results indicate that EOS can effectively regulate a driver's anger emotions, especially with the banana odor showing superior effects. Under banana odor stimulus, synchronization between the parietal and temporal lobes significantly decreased. Notably, the regulatory effect of banana odor is optimal and exhibits sustained efficacy. The regulatory effect of banana odor on anger emotions is persistent. Furthermore, the impact of banana odor significantly reduces the distribution of high-energy activation states in the parietal lobe region. Our findings provide new insights into the dynamic characterization of functional connectivity during anger-driving regulation and demonstrate the potential of using EOS as a reliable tool for regulating angry driving.

Children and adolescents with primary headaches exhibit altered sensory profiles - a multi-modal investigation

BACKGROUND

Pediatric headache is an increasing medical problem that has adverse effects on children's quality of life, academic performance, and social functioning. Children with primary headaches exhibit enhanced sensory sensitivity compared to their healthy peers. However, comprehensive investigations including multimodal sensory sensitivity assessment are lacking. This study aimed to compare sensory sensitivity of children with primary headaches with their healthy peers across multiple sensory domains.

METHODS

The study included 172 participants aged 6 to 17 years (M = 13.09, SD = 3.02 years; 120 girls). Of these 80 participants were patients with migraine, 23 were patients with tension-type headache, and 69 were healthy controls. The following sensory measures were obtained: Mechanical Detection Threshold (MDT), Mechanical Pain Threshold (MPT), Mechanical Pain Sensitivity (MPS), detection and pain threshold for Transcutaneous Electrical Nerve Stimulation (TENS), olfactory and intranasal trigeminal detection threshold, and odor identification ability. Sensory sensitivity was compared between groups with a series of Kruskal-Wallis tests. Binomial regression models were used to compare the relative utility of sensory sensitivity measures in classifying participants into patients and healthy controls, as well as into patients with migraine and tension-type headache.

RESULTS

Patients with migraine had lower MPT measured at the forearm than patients with tension-type headaches and healthy controls. MPS was higher in patients with migraine than in healthy controls. All patients with headaches had lower detection threshold of TENS and higher olfactory sensitivity. Healthy controls showed increased intranasal trigeminal sensitivity. Scores in MPS, TENS, and olfactory and trigeminal thresholds were significantly predicting presence of primary headaches. Additionally, scores in MPT, olfactory and trigeminal threshold were positive predictors of type of headache.

CONCLUSIONS

Children with primary headaches exhibit different sensory profiles than healthy controls. The obtained results suggest presence of increased overall, multimodal sensitivity in children with primary headaches, what may negatively impact daily functioning and contribute to further pain chronification.

TRIAL REGISTRATION

The study was registered in the German Registry of Clinical Trials (DRKS) DRKS00021062.

Brain-wide pleiotropy investigation of alcohol drinking and tobacco smoking behaviors

To investigate the pleiotropic mechanisms linking brain structure and function to alcohol drinking and tobacco smoking, we integrated genome-wide data generated by the GWAS and Sequencing Consortium of Alcohol and Nicotine use (GSCAN; up to 805,431 participants) with information related to 3,935 brain imaging-derived phenotypes (IDPs) available from UK Biobank (N=33,224). We observed global genetic correlation of smoking behaviors with white matter hyperintensities, the morphology of the superior longitudinal fasciculus, and the mean thickness of pole-occipital. With respect to the latter brain IDP, we identified a local genetic correlation with age at which the individual began smoking regularly (hg38 chr2:35,895,678-36,640,246: rho=1, p=1.01×10 -5 ). This region has been previously associated with smoking initiation, educational attainment, chronotype, and cortical thickness. Our genetically informed causal inference analysis using both latent causal variable approach and Mendelian randomization linked the activity of prefrontal and premotor cortex and that of superior and inferior precentral sulci, and cingulate sulci to the number of alcoholic drinks per week (genetic causality proportion, gcp=0.38, p=8.9×10 -4 , rho=-0.18±0.07; inverse variance weighting, IVW beta=-0.04, 95%CI=-0.07 - -0.01). This relationship could be related to the role of these brain regions in the modulation of reward-seeking motivation and the processing of social cues. Overall, our brain-wide investigation highlighted that different pleiotropic mechanisms likely contribute to the relationship of brain structure and function with alcohol drinking and tobacco smoking, suggesting decision-making activities and chemosensory processing as modulators of propensity towards alcohol and tobacco consumption.

Time-frequency analysis of gustatory event related potentials (gERP) in taste disorders

In taste disorders, the key to a correct diagnosis and an adequate treatment is an objective assessment. Compared to psychophysical tests, EEG-derived gustatory event-related potentials (gERP) could be used as a less biased measure. However, the responses identified using conventional time-domain averaging show a low signal-to-noise ratio. This study included 44 patients with dysgeusia and 59 healthy participants, who underwent a comprehensive clinical examination of gustatory function. gERPs were recorded in response to stimulation with two concentrations of salty solutions, which were applied with a high precision gustometer. Group differences were examined using gERP analyzed in the canonical time domain and with Time-Frequency Analyses (TFA). Dysgeusic patients showed significantly lower scores for gustatory chemical and electrical stimuli. gERPs failed to show significant differences in amplitudes or latencies between groups. However, TFA showed that gustatory activations were characterized by a stronger power in controls than in patients in the low frequencies (0.1-4 Hz), and a higher desynchronization in the alpha-band (8-12 Hz). Hence, gERPs reflect the altered taste sensation in patients with dysgeusia. TFA appears to enhance the signal-to-noise ratio commonly present when using conventional time-domain averaging, and might be of assistance for the diagnosis of dysgeusia.