Background: Exposure to bright light such as sunlight elicits a sneeze or prickling sensation in about one of every four individuals. This study presents the first scientific examination of this phenomenon, called 'the photic sneeze reflex'.
Methodology And Principal Findings: In the present experiment, 'photic sneezers' and controls were exposed to a standard checkerboard stimulus (block 1) and bright flashing lights (block 2) while their EEG (electro-encephalogram) was recorded. Remarkably, we found a generally enhanced excitability of the visual cortex (mainly in the cuneus) to visual stimuli in 'photic sneezers' compared with control subjects. In addition, a stronger prickling sensation in the nose of photic sneezers was found to be associated with activation in the insula and stronger activation in the secondary somatosensory cortex.
Conclusion: We propose that the photic sneeze phenomenon might be the consequence of higher sensitivity to visual stimuli in the visual cortex and of co-activation of somatosensory areas. The 'photic sneeze reflex' is therefore not a classical reflex that occurs only at a brainstem or spinal cord level but, in stark contrast to many theories, involves also specific cortical areas.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2821404 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0009208 | PLOS |
Pharmaceutics
December 2024
Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA.
Nucleoside reverse transcriptase inhibitors (NRTIs) are the backbone of highly active antiretroviral therapy (HAART)-the current standard of care for treating human immunodeficiency virus (HIV) infection. Despite their efficacy, NRTIs cause numerous treatment-limiting adverse effects, including a distinct peripheral neuropathy, called antiretroviral toxic neuropathy (ATN). ATN primarily affects the extremities with shock-like tingling pain, a pins-and-needles prickling sensation, and numbness.
View Article and Find Full Text PDFAust J Gen Pract
March 2024
BPT, PhD, Professor, School of Health Sciences and Social Work, Griffith University, Brisbane and Gold Coast, Qld; Research Fellow, Menzies Health Institute Queensland, Brisbane and Gold Coast, Qld; Professor, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands.
Background And Objectives: People with diabetic peripheral neuropathy (DPN) report fluctuating foot symptoms. This study used ecological momentary assessment to: (1) compare foot symptoms between days, time points and periods with/without preceding physical activity or pain medication; and (2) determine relationships between symptoms and endogenous pain modulation.
Method: Ten low-active Australian adults with probable DPN underwent temporal summation of pain (TSP) and conditioned pain modulation (CPM) then completed mobile phone surveys five times daily for seven days, where they recorded the intensity of six foot symptoms and whether they performed physical activity or consumed pain medication in the preceding three hours.
Skin Res Technol
February 2024
College of Textile Science and Engineering (International Institute of Silk), Key Laboratory of Intelligent Textile and Flexible Interconnection of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou, China.
Background: The complex network connections, information transmission and organization play key roles in brain cognition on sensory stimulation. Previous studies showed that several brain regions of somatosensory, motor, emotional, cognitive, etc. are linked to fabric-evoked prickle.
View Article and Find Full Text PDFCurr Rheumatol Rev
April 2024
Department of Rheumatology, Military Hospital, Tunis, Tunisia.
Acroparesthesia is a symptom characterized by a subjective sensation, such as numbness, tingling, prickling, and reduced sensation, affecting the extremities (fingers and toes). Despite its frequency, data regarding its diagnostic approach and management are scarce. The etiological diagnosis of acroparesthesia is sometimes challenging since it can be due to abnormality anywhere along the sensory pathway from the peripheral nervous system to the cerebral cortex.
View Article and Find Full Text PDFSkin Res Technol
September 2023
College of Education Science, Quanzhou Normal University, Fujian, China.
Background: A kind of prickle sensation, which is a composite feeling of pain and itch, can be evoked by mechanical stimulation of fiber ends from fabric surface against to human hairy skin, rather than glabrous skin. Now, a functional magnetic resonance imaging (fMRI) study was conducted to investigate the cognitive differences in the brain for mechanical prickling stimuli to the two types of skin.
Materials And Methods: A nylon filament with the diameter of 205 μm and the length of 8 mm was used to deliver mechanical prickling stimuli respectively to two skin sites, fingertip (glabrous skin) and volar forearm (hairy skin), of eight healthy male subjects.
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