Abrupt light transitions in illuminance and correlated colour temperature result in different temporal dynamics and interindividual variability for sensation, comfort and alertness.

Detailed insights in both visual effects of light and effects beyond vision due to manipulations in illuminance and correlated color temperature (CCT) are needed to optimize study protocols as well as to design light scenarios for practical applications. This study investigated temporal dynamics and interindividual variability in subjective evaluations of sensation, comfort and mood as well as subjective and objective measures of alertness, arousal and thermoregulation following abrupt transitions in illuminance and CCT in a mild cold environment. The results revealed that effects could be uniquely attributed to changes in illuminance or CCT. No interaction effects of illuminance and CCT were found for any of these markers. Responses to the abrupt transitions in illuminance and CCT always occurred immediately and exclusively amongst the subjective measures. Most of these responses diminished over time within the 45-minute light manipulation. In this period, no responses were found for objective measures of vigilance, arousal or thermoregulation. Significant interindividual variability occurred only in the visual comfort evaluation in response to changes in the intensity of the light. The results indicate that the design of dynamic light scenarios aimed to enhance human alertness and vitality requires tailoring to the individual to create visually comfortable environments.

Cryptochrome 1 mediates light-dependent inclination magnetosensing in monarch butterflies.

Many animals use the Earth's geomagnetic field for orientation and navigation. Yet, the molecular and cellular underpinnings of the magnetic sense remain largely unknown. A biophysical model proposed that magnetoreception can be achieved through quantum effects of magnetically-sensitive radical pairs formed by the photoexcitation of cryptochrome (CRY) proteins. Studies in Drosophila are the only ones to date to have provided compelling evidence for the ultraviolet (UV)-A/blue light-sensitive type 1 CRY (CRY1) involvement in animal magnetoreception, and surprisingly extended this discovery to the light-insensitive mammalian-like type 2 CRYs (CRY2s) of both monarchs and humans. Here, we show that monarchs respond to a reversal of the inclination of the Earth's magnetic field in an UV-A/blue light and CRY1, but not CRY2, dependent manner. We further demonstrate that both antennae and eyes, which express CRY1, are magnetosensory organs. Our work argues that only light-sensitive CRYs function in animal light-dependent inclination-based magnetic sensing.

Sensory and motor responses after photobiomodulation associated with physiotherapy in patients with incomplete spinal cord injury: clinical, randomized trial.

Complete or incomplete spinal cord injury (SCI) results in permanent neurological deficits due to the interruption of nerve impulses, causing the loss of motor and sensory function, which leads to a reduction in quality of life. The focus of rehabilitation for such individuals is to improve quality of life and promote functional recovery. Photobiomodulation (PBM) has proved to be promising complementary treatment in cases of SCI. The aim of the present study was to investigate the effects of PBM combined with physiotherapy on sensory-motor responses below the level of the injury and quality of life in individuals with SCI. Thirty participants were randomized for allocation to the PBM group (active PBM + physiotherapy) or sham group (sham PBM + physiotherapy). Physiotherapy was administered three times a week. Sensitivity and motor skills were evaluated using the ASIA impairment scale. Quality of life was assessed using the WHOQOL-BREF questionnaire. The data were analyzed with the level of significance set to 5%. Improvements in sensitivity and an increase in the perception of muscle contraction were found in the active PBM group 30 days after treatment compared with the sham group. The results of the WHOQOL-BREF questionnaire revealed a significant difference in general quality of life favoring the active PBM group over the sham group after treatment. Physiotherapy combined with PBM leads to better sensory-motor recovery in patients with SCI as well as a better perception of health and quality of life. Trial registration identifier: NCT03031223.

Alleviation of Dyspnea Sensation by Phototherapy in Healthy Adults.

BACKGROUND: Because both dyspnea and pain have common features from a clinical and physiologic point of view, we hypothesized that stellate ganglion irradiation by using a linear polarized near-infrared ray device, which is often used for pain management, might be applicable for dyspnea relief. To evaluate the use of stellate ganglion irradiation as a novel noninvasive treatment for dyspnea, we investigated the influence of stellate ganglion irradiation on dyspnea. METHODS: Perceptions of dyspnea were examined with or without stellate ganglion irradiation in 28 healthy adults. The sensation of breathing difficulty was induced by a two-way non-rebreathing valves with linear inspiratory resistance (R) of 0, 10, 20, and 30 cm H2O/L/s. Dyspnea was evaluated with the modified Borg scale to determine subjects' discomfort level. Stellate ganglion irradiation was performed by intermittent irradiation near the bilateral stellate ganglion by using a linear polarized near-infrared ray device. RESULTS: There were significant changes from baseline at R = 10 cm H2O/L/s (P = .007), R = 20 cm H2O/L/s (P = .005), and R = 30 cm H2O/L/s (P = .009). For each resistive load, the mean dyspnea sensation score was lower with stellate ganglion irradiation compared with sham irradiation, with significant differences (P = .003 at R = 0 cm H2O/L/s; P < .001 at R = 10, 20, 30 cm H2O/L/s). There was a significantly lower slope of the dyspnea response for the linear regression of the loads and Borg scores in the stellate ganglion irradiation versus sham treatment (P = .003). CONCLUSIONS: Stellate ganglion irradiation significantly alleviated dyspnea induced by an external inspiratory load in healthy adults. Stellate ganglion irradiation might be an option to treat dyspnea in some cases. Further studies in individuals with diverse types of dyspnea and clinical settings are warranted.

Abnormal neuronal response to rectal and anal stimuli in patients treated with primary radiotherapy for anal cancer.

INTRODUCTION: Sphincter-sparing radiotherapy or chemoradiation (RT/CRT) have become the standard treatments for most patients with anal cancer. Unfortunately, long-term survivors often suffer from severe bowel symptoms indicating sensory dysfunction. The aim of the present study was to characterize the sensory pathways of the brain-gut axis after radiotherapy for anal cancer. METHOD: Cortical evoked potentials (CEPs) were recorded during repeated, rapid balloon distensions of the rectum and anal canal in 13 patients with anal cancer treated with radiotherapy or chemoradiation and in 17 healthy volunteers. Latencies and amplitudes of rectal CEPs were compared between the groups. CEPs from both rectal and anal distensions were examined using single sweep spectral band analysis to determine the relative amplitude of five spectral bands as a proxy of neuronal processing. RESULTS: Groups were comparable by age (62.4 ±â€¯7.8 vs 58.9 ±â€¯8.9, p < 0.32) and gender. Patients had a mean Wexner fecal incontinence score of 5.5 (±3.8) and median LARS Score of 29 (0-39). Rectal CEP latencies were prolonged in patients (F = 11.7; p < 0.001), whereas amplitudes were similar (F = 0.003; p = 0.96). Spectral analysis of CEPs from rectal distensions showed significant differences between groups in theta (4-8 Hz), alpha (8-12 Hz), beta (12-32 Hz) and gamma (32-70 Hz) bands (all p < 0.001) and CEPs from anal distensions showed significant differences in the alpha, beta and gamma bands (all p ≤ 0.002). CONCLUSION: Patients treated with RT/CRT for anal cancer have impaired ano-rectal sensory pathways and abnormal cortical processing. This may play a central role for the pathogenesis of late proctopathy.

Realidad virtual como herramienta en fisioterapia, ¿ficción o realidad? / Virtual reality as a tool in physiotherapy: Fiction or reality?

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Sensory Conflict Disrupts Activity of the Drosophila Circadian Network.

Periodic changes in light and temperature synchronize the Drosophila circadian clock, but the question of how the fly brain integrates these two input pathways to set circadian time remains unanswered. We explore multisensory cue combination by testing the resilience of the circadian network to conflicting environmental inputs. We show that misaligned light and temperature cycles can lead to dramatic changes in the daily locomotor activities of wild-type flies during and after exposure to sensory conflict. This altered behavior is associated with a drastic reduction in the amplitude of PERIOD (PER) oscillations in brain clock neurons and desynchronization between light- and temperature-sensitive neuronal subgroups. The behavioral disruption depends heavily on the phase relationship between light and temperature signals. Our results represent a systematic quantification of multisensory integration in the Drosophila circadian system and lend further support to the view of the clock as a network of coupled oscillatory subunits.

The Effects of Increasing Ocular Surface Stimulation on Blinking and Tear Secretion.

PURPOSE: To investigate the effect of varying levels of ocular surface stimulation on the timing and amplitude of the blink and tear secretion. METHODS: Following instillation of fluorescein dye, increasing levels of air flow were directed toward the central corneas of 10 healthy subjects. Interblink interval (IBI), tear meniscus height (TMH), and fluorescence intensity were measured simultaneously. Because blinking can obscure changes in TMH, we developed novel measures of tear secretion by calculating tear meniscus fluorescein concentration (TMFC) from intensity using a mathematical model. The change of TMH and TMFC over trials and the slope of the TMFC within each IBI (IBI-TTR) were further calculated. RESULTS: The mean IBI was decreased by 8.08 ± 8.54 seconds from baseline to maximum air stimulation. The TMH increase was highly variable (0.41 ± 0.39 mm) among subjects, compared to the fluorescence tear turnover metrics: decrease in TMFC of 2.84 ± 0.98 natural logarithm or ln(%) and IBI-TTR of 0.065 ± 0.032 ln(%)/sec. Ocular surface stimulation was highly correlated with the TMFC and IBI-TTR, but less so with TMH (Pearson's r = 0.71, 0.69, and 0.40, P < 0.01, respectively). Blinking and tearing were significantly correlated with each other (Pearson's r = 0.56, P < 0.01), but tearing lagged behind by an average of 6.54 ± 4.07 seconds. CONCLUSIONS: Blinking and tearing share a common origin with sensory stimulation at the ocular surface. Both showed a dose-response increase with surface stimulation and were correlated with each other. These methods can potentially be used to understand alterations in ocular surface sensory function and associated protective responses in dry eye and other disorders of the ocular surface.

Extraretinal induced visual sensations during IMRT of the brain.

BACKGROUND: We observed visual sensations (VSs) in patients undergoing intensity modulated radiotherapy (IMRT) of the brain without the beam passing through ocular structures. We analyzed this phenomenon especially with regards to reproducibility, and origin. METHODS AND FINDINGS: Analyzed were ten consecutive patients (aged 41-71 years) with glioblastoma multiforme who received pulsed IMRT (total dose 60Gy) with helical tomotherapy (TT). A megavolt-CT (MVCT) was performed daily before treatment. VSs were reported and recorded using a triggered event recorder. The frequency of VSs was calculated and VSs were correlated with beam direction and couch position. Subjective patient perception was plotted on an 8x8 visual field (VF) matrix. Distance to the orbital roof (OR) from the first beam causing a VS was calculated from the Dicom radiation therapy data and MVCT data. During 175 treatment sessions (average 17.5 per patient) 5959 VSs were recorded and analyzed. VSs occurred only during the treatment session not during the MVCTs. Plotting events over time revealed patient-specific patterns. The average cranio-caudad extension of VS-inducing area was 63.4mm (range 43.24-92.1mm). The maximum distance between the first VS and the OR was 56.1mm so that direct interaction with the retina is unlikely. Data on subjective visual perception showed that VSs occurred mainly in the upper right and left quadrants of the VF. Within the visual pathways the highest probability for origin of VSs was seen in the optic chiasm and the optic tract (22%). CONCLUSIONS: There is clear evidence that interaction of photon irradiation with neuronal structures distant from the eye can lead to VSs.

Pathophysiology of late anorectal dysfunction following external beam radiotherapy for prostate cancer.

BACKGROUND: Patients treated with external beam radiotherapy (EBRT) may suffer from long-term anorectal adverse effects. The purpose of the present study was to assess long-term functional and structural anorectal changes in patients previously treated with EBRT for prostate cancer and to suggest the mechanism behind the development of the adverse effects. MATERIAL AND METHODS: Our previously proposed RT-induced anorectal dysfunction (RT-ARD) score, developed with the intention to survey anorectal dysfunction was used to identify patients with and without anorectal symptoms. Among 309 patients surveyed with the questionnaire, we chose 23 patients with the highest RT-ARD score and 19 patients with the lowest RT-ARD score. They were investigated by multimodal rectal sensory stimulation, standard anal physiological tests. Changes of the rectal mucosa were assessed by flexible sigmoidoscopy and graded by the Vienna Rectoscopy Score (VRS). RESULTS: The mean follow-up time was 3.8 (range, 2.8; 8.6) years in patients with high RT-ARD and 3.8 (range, 2.6; 5.9) in patients with low RT-ARD. Endoscopic evaluation revealed higher VRS scores in patients with high RT-ARD compared to patients with low RT-ARD (p = 0.002). Patients with high RT-ARD had increased rectal sensory response to distension manifested both as volume (p = 0.006) and cross-sectional area (p = 0.04), and they had reduced maximum anal resting pressure assessed by anal manometri (p = 0.02). CONCLUSIONS: Long-term anorectal symptoms correlate to changes in anorectal biomechanical properties and rectal mucosal injury. Our data suggests that RT-induced long-term anorectal dysfunction is multifactorial caused by injury of the rectal mucosa and the internal anal sphincter combined with increased rectal sensitivity and reduced rectal functional capacity.

Radiofrequency contact currents: sensory responses and dosimetry.

The process of setting science-based exposure standards (or guidelines) for radiofrequency (RF) contact current exposure has been disadvantaged by a lack of relevant data. The authors first review the essential features and results of the available studies and illustrate the apparent discrepancies among them. Then, they examine the manner in which current was administered in these studies and suggest as to how the physical relationship of a contacting finger to the current electrode may play a role in affecting sensory thresholds specific to those configurations. A major factor in this analysis relates to whether current density is uniformly distributed across the contact area or whether an electrode's 'edge effects' enhance currents with a net effect of decreasing apparent thresholds, when expressed as the bulk current entering a subject. For an exposure with a clear hazard potential, thresholds of human sensory response to RF currents require further investigation.

Laryngeal sensation and pharyngeal delay time after (chemo)radiotherapy.

The objective of the study was to evaluate the association between changes in laryngeal sensation and initiation of swallowing reflex or swallowing function before and after (chemo)radiotherapy. A prospective study was conducted in a tertiary referral university hospital. Thirteen patients who received (chemo)radiotherapy for treatment of laryngeal or hypopharyngeal cancer were included. Laryngeal sensation was evaluated at the tip of the epiglottis before and 1, 3 months, and 1 year after (chemo)radiotherapy. Videofluoroscopy was performed at the same time. Quantitative determinations included changes in laryngeal sensation, computed analysis of pharyngeal delay time, the distance and velocity of hyoid bone movement during the phase of hyoid excursion, and pharyngeal residue rate (the proportion of the bolus that was left as residue in the pharynx at the first swallow). Laryngeal sensation significantly deteriorated 1 month after (chemo)radiotherapy, but there was a tendency to return to pretreatment levels 1 year after treatment. Neither pharyngeal delay time nor displacement of the hyoid bone changed significantly before and after (chemo)radiotherapy. In addition, there was no significant difference in the mean velocity of hyoid bone movement and the amount of stasis in the pharynx at the first swallow before and after (chemo)radiotherapy. After (chemo)radiotherapy, laryngeal sensation deteriorated. But, in this study, videofluoroscopy showed that swallowing reflex and function were maintained.

Lower-level laser therapy improves neurosensory disorders resulting from bilateral mandibular sagittal split osteotomy: a randomized crossover clinical trial.

Bilateral sagittal split osteotomy (BSSO) is a technique commonly used to correct mandibular disproportion but many patients experience hypoaesthesia of the inferior alveolar nerve (IAN). The purpose of this study was to verify the effectiveness of using a low-level laser therapy protocol after BSSO. The 10 patients in our study, who underwent BSSO with Le Fort I osteotomy and had low-level laser therapy on one side of the jaw, were evaluated over a period of 60 days. The data for the treated and non-treated sides were compared post-operatively. At 15, 30 and 60 days after surgery, when sensitivity was recovered on both sides. On the treated side, recovery was faster and was almost complete at the time of the last evaluation. We suggest that this lower-level laser therapy protocol can improve tissue response and accelerate the recovery of neurosensory disorders following BSSO. (NCT01530100).

Argon plasma coagulation therapy versus topical formalin for intractable rectal bleeding and anorectal dysfunction after radiation therapy for prostate carcinoma.

PURPOSE: To evaluate and compare the effect of argon plasma coagulation (APC) and topical formalin for intractable rectal bleeding and anorectal dysfunction associated with chronic radiation proctitis. METHODS AND MATERIALS: Thirty men (median age, 72 years; range, 49-87 years) with intractable rectal bleeding (defined as ≥1× per week and/or requiring blood transfusions) after radiation therapy for prostate carcinoma were randomized to treatment with APC (n=17) or topical formalin (n=13). Each patient underwent evaluations of (1) anorectal symptoms (validated questionnaires, including modified Late Effects in Normal Tissues-Subjective, Objective, Management, and Analytic and visual analogue scales for rectal bleeding); (2) anorectal motor and sensory function (manometry and graded rectal balloon distension); and (3) anal sphincteric morphology (endoanal ultrasound) before and after the treatment endpoint (defined as reduction in rectal bleeding to 1× per month or better, reduction in visual analogue scales to ≤25 mm, and no longer needing blood transfusions). RESULTS: The treatment endpoint was achieved in 94% of the APC group and 100% of the topical formalin group after a median (range) of 2 (1-5) sessions of either treatment. After a follow-up duration of 111 (29-170) months, only 1 patient in each group needed further treatment. Reductions in rectal compliance and volumes of sensory perception occurred after APC, but no effect on anorectal symptoms other than rectal bleeding was observed. There were no differences between APC and topical formalin for anorectal symptoms and function, nor for anal sphincteric morphology. CONCLUSIONS: Argon plasma coagulation and topical formalin had comparable efficacy in the durable control of rectal bleeding associated with chronic radiation proctitis but had no beneficial effect on anorectal dysfunction.

Changes in the micromorphology of the corneal subbasal nerve plexus in patients after plaque brachytherapy.

BACKGROUND: To quantify the development of radiation neuropathy in corneal subbasal nerve plexus (SNP) after plaque brachytherapy, and the subsequent regeneration of SNP micromorphology and corneal sensation. METHODS: Nine eyes of 9 melanoma patients (ciliary body: 3, iris: 2, conjunctiva: 4) underwent brachytherapy (ruthenium-106 plaque, dose to tumour base: 523 ± 231 Gy). SNP micromorphology was assessed by in-vivo confocal microscopy. Using software developed in-house, pre-irradiation findings were compared with those obtained after 3 days, 1, 4 and 7 months, and related to radiation dose and corneal sensation. RESULTS: After 3 days nerve fibres were absent from the applicator zone and central cornea, and corneal sensation was abolished. The earliest regenerating fibres were seen at the one-month follow-up. By 4 months SNP structures had increased to one-third of pre-treatment status (based on nerve fibre density and nerve fibre count), and corneal sensation had returned to approximately two-thirds of pre-irradiation values. Regeneration of SNP and corneal sensation was nearly complete 7 months after plaque brachytherapy. CONCLUSIONS: The evaluation of SNP micromorphology and corneal sensation is a reliable and clinically useful method for assessing neuropathy after plaque brachytherapy. Radiation-induced neuropathy of corneal nerves develops quickly and is partly reversible within 7 months. The clinical impact of radiation-induced SNP damage is moderate.

Cognition and sensation in very high static magnetic fields: a randomized case-crossover study with different field strengths.

PURPOSE: To establish the extent to which representative cognitive functions in subjects undergoing magnetic resonance (MR) imaging are acutely impaired by static magnetic fields of varying field strengths. MATERIALS AND METHODS: This study was approved by the local ethics committee, and informed consent was obtained from all subjects. In this single-blind case-crossover study, 41 healthy subjects underwent an extensive neuropsychologic examination while in MR units of differing field strengths (1.5, 3.0, and 7.0 T), including a mock imager with no magnetic field as a control condition. Subjects were blinded to field strength. Tests were performed while subjects were lying still in the MR unit and while the examination table was moved. The tests covered a representative set of cognitive functions, such as memory, eye-hand coordination, attention, reaction time, and visual discrimination. Subjective sensory perceptions were also assessed. Effects were analyzed with a repeated-measures analysis of variance; the within-subject factors were field strength (0, 1.5, 3.0, and 7.0 T) and state (static, dynamic). RESULTS: Static magnetic fields were not found to have a significant effect on cognitive function at any field strength. However, sensory perceptions did vary according to field strength. Dizziness, nystagmus, phosphenes, and head ringing were related to the strength of the static magnetic field. CONCLUSION: Static magnetic fields as high as 7.0 T did not have a significant effect on cognition.

Pathophysiology and natural history of anorectal sequelae following radiation therapy for carcinoma of the prostate.

PURPOSE: To characterize the prevalence, pathophysiology, and natural history of chronic radiation proctitis 5 years following radiation therapy (RT) for localized carcinoma of the prostate. METHODS AND MATERIALS: Studies were performed in 34 patients (median age 68 years; range 54-79) previously randomly assigned to either 64 Gy in 32 fractions over 6.4 weeks or 55 Gy in 20 fractions over 4 weeks RT schedule using 2- and later 3-dimensional treatment technique for localized prostate carcinoma. Each patient underwent evaluations of (1) gastrointestinal (GI) symptoms (Modified Late Effects in Normal Tissues Subjective, Objective, Management and Analytic scales including effect on activities of daily living [ADLs]); (2) anorectal motor and sensory function (manometry and graded balloon distension); and (3) anal sphincteric morphology (endoanal ultrasound) before RT, at 1 month, and annually for 5 years after its completion. RESULTS: Total GI symptom scores increased after RT and remained above baseline levels at 5 years and were associated with reductions in (1) basal anal pressures, (2) responses to squeeze and increased intra-abdominal pressure, (3) rectal compliance and (4) rectal volumes of sensory perception. Anal sphincter morphology was unchanged. At 5 years, 44% and 21% of patients reported urgency of defecation and rectal bleeding, respectively, and 48% impairment of ADLs. GI symptom scores and parameters of anorectal function and anal sphincter morphology did not differ between the 2 RT schedules or treatment techniques. CONCLUSIONS: Five years after RT for prostate carcinoma, anorectal symptoms continue to have a significant impact on ADLs of almost 50% of patients. These symptoms are associated with anorectal dysfunction independent of the RT schedules or treatment techniques reported here.

Differences in radiation dosimetry and anorectal function testing imply that anorectal symptoms may arise from different anatomic substrates.

PURPOSE: To explore the influence of functional changes and dosimetric parameters on specific incontinence-related anorectal complaints after prostate external beam radiotherapy and to estimate dose-effect relations for the anal wall and rectal wall. METHODS AND MATERIALS: Sixty patients, irradiated for localized prostate cancer, underwent anorectal manometry and barostat measurements to evaluate anal pressures, rectal capacity, and rectal sensory functions. In addition, 30 untreated men were analyzed as a control group. In 36 irradiated patients, the anal wall and rectal wall were retrospectively delineated on planning computed tomography scans, and dosimetric parameters were retrieved from the treatment plans. Functional and dosimetric parameters were compared between patients with and without complaints, focusing on urgency, incontinence, and frequency. RESULTS: After external beam radiotherapy, reduced anal pressures and tolerated rectal volumes were observed, irrespective of complaints. Patients with urgency and/or incontinence showed significantly lower anal resting pressures (mean 38 and 39 vs. 49 and 50 mm Hg) and lower tolerated rectal pressures (mean 28 and 28 vs. 33 and 34 mm Hg), compared to patients without these complaints. In patients with frequency, almost all rectal parameters were reduced. Several dosimetric parameters to the anal wall and rectal wall were predictive for urgency (e.g., anal D(mean)>38 Gy), whereas some anal wall parameters correlated to incontinence and no dose-effect relation for frequency was found. CONCLUSIONS: Anorectal function deteriorates after external beam radiotherapy. Different incontinence-related complaints show specific anorectal dysfunctions, suggesting different anatomic and pathophysiologic substrates: urgency and incontinence seem to originate from both anal wall and rectal wall, whereas frequency seems associated with rectal wall dysfunction. Also, dose-effect relations differed between these complaints. This implies that anal wall and rectal wall should be considered separate organs in radiotherapy planning.

Effects of static magnetic fields on cognition, vital signs, and sensory perception: a meta-analysis.

To evaluate whether cognitive processes, sensory perception, and vital signs might be influenced by static magnetic fields in magnetic resonance imaging (MRI), which could pose a risk for health personnel and patients, we conducted a meta-analysis of studies that examined effects of static magnetic fields. Studies covering the time from 1992 to 2007 were selected. Cohen's d effects sizes were used and combined in different categories of neuropsychology (reaction time, visual processing, eye-hand coordination, and working memory). Additionally, effects of static magnetic fields on sensory perception and vital signs were analyzed. In the category "neuropsychology," only effects on the visual system were homogeneous, showing a statistically significant impairment as a result of exposure to static magnetic fields (d = -0.415). Vital signs were not affected and effects on sensory perceptions included an increase of dizziness and vertigo, primarily caused by movement during static magnetic field gradient exposures. The number of studies dealing with this topic is very small and the experimental set-up of some of the analyzed studies makes it difficult to accurately determine the effects of static magnetic fields by themselves, excluding nonspecific factors. The implications of these results for MRI lead to suggestions for improvement in research designs.

Human cryptochrome exhibits light-dependent magnetosensitivity.

Humans are not believed to have a magnetic sense, even though many animals use the Earth's magnetic field for orientation and navigation. One model of magnetosensing in animals proposes that geomagnetic fields are perceived by light-sensitive chemical reactions involving the flavoprotein cryptochrome (CRY). Here we show using a transgenic approach that human CRY2, which is heavily expressed in the retina, can function as a magnetosensor in the magnetoreception system of Drosophila and that it does so in a light-dependent manner. The results show that human CRY2 has the molecular capability to function as a light-sensitive magnetosensor and reopen an area of sensory biology that is ready for further exploration in humans.