Objective: Olfactory and trigeminal systems interact and contribute to the perception of odorants. This study was aimed at investigating the effect of local anesthesia on olfaction.
Methods: One percent of tetracaine on a cotton swab was applied intranasally at three different locations in 20 volunteers and 4% of lidocaine was applied to the olfactory cleft in a head-down position. Before and after anesthesia, self-assessment, psychometric testing and olfactory event-related potentials [OERPs, using H(2)S and phenyl ethyl alcohol (PEA)], and chemosomatosensory event-related potentials (CSSERPs, using CO(2)) were examined.
Results: Anesthesia at all four locations significantly lowered the perceived self-assessment of olfaction, while using the cotton swab only anesthesia in the middle meatus elevated threshold (P = 0.020), lowered discrimination (P = 0.015), and prolonged OERP (PEA, P = 0.008; H(2)S, P = 0.016), as well as CSSERPs latencies (CO(2), P = 0.020). However, complete temporary anosmia was only achieved after applying 4% lidocaine into the olfactory cleft.
Conclusions: Intranasal anesthesia applied with a swab reduced self-assessment of olfaction but was unable to produce anosmia. Psychometric test results were concordant with changes in chemosensory event-related potentials.
Significance: Temporary anosmia is technically difficult to achieve but could be demonstrated for the first time using local anesthesia. Even though anesthesia influences self-assessment, measurable olfactory function can remain unchanged.
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http://dx.doi.org/10.1016/j.clinph.2003.12.028 | DOI Listing |
J Neurosci
January 2025
Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
Action potentials (spikes) are regenerated at each node of Ranvier during saltatory transmission along a myelinated axon. The high density of voltage-gated sodium channels required by nodes to reliably transmit spikes increases the risk of ectopic spike generation in the axon. Here we show that ectopic spiking is avoided because K1 channels prevent nodes from responding to slow depolarization; instead, axons respond selectively to rapid depolarization because K1 channels implement a high-pass filter.
View Article and Find Full Text PDFBraz J Otorhinolaryngol
January 2025
Antwerp University Hospital (UZA), Department of Otorhinolaryngology, Head and Neck Surgery, Edegem, Belgium; University of Antwerp, Faculty of Medicine and Health Sciences, Department of Translational Neurosciences, Resonant Labs Antwerp, Antwerp, Belgium.
Objectives: Hearing loss is associated with increased cognitive decline and incident dementia in older adults. Given the rapidly rising incidence of dementia, management of modifiable risk factors such as hearing loss, is essential to mitigate the impact on the individual and society in general. In this narrative review, we discuss the current state-of-art with respect to studying cognitive function before and after cochlear implantation in the elderly population.
View Article and Find Full Text PDFJ Neurosci
January 2025
Carney Institute for Brain Science, Brown University, Providence, RI 02912
The neuromuscular junction (NMJ) is the linchpin of nerve-evoked muscle contraction. Broadly, the function of the NMJ is to transduce nerve action potentials into muscle fiber action potentials (MFAPs). Efficient neuromuscular transmission requires both cholinergic signaling, responsible for generation of endplate potentials (EPPs), and excitation, the amplification of the EPP by postsynaptic voltage-gated sodium channels (Nav1.
View Article and Find Full Text PDFInt J Psychophysiol
January 2025
Center for Cognitive & Brain Health, Northeastern University, Boston, MA, USA; Department of Physical Therapy, Movement, & Rehabilitation Sciences, Northeastern University, Boston, MA, USA. Electronic address:
Introduction: Prolonged sitting can acutely reduce working memory (WM) in individuals with overweight and obesity (OW/OB) who show executive function deficits. Interrupting prolonged sitting with brief PA bouts may counter these effects. However, the benefits of such interventions on behavioral and neuroelectric indices of WM and whether neurocognitive responses are associated with postprandial glycemic responses in young and middle-aged adults with OW/OB remain unknown.
View Article and Find Full Text PDFDev Psychobiol
January 2025
Department of Psychology, University of Texas at Dallas, Richardson, Texas, USA.
Aggression is commonly associated with increased experiences of peer rejection and maladaptive social information processing biases throughout development. Little is known about the neural correlates of peer rejection that might underlie social information processing biases, and whether these neural correlates are common or different across early- and mid-adolescents on a continuum of aggression. Using the Cyberball task, we examined mediofrontal theta (4-7 Hz) event-related EEG spectral power during conditions of explicit and ambiguous social exclusion in 117 participants (57 early adolescents, ages 10-12 years, and 60 mid-adolescents, ages 14-16 years).
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