Behavioral effects of exposure to nuclear magnetic resonance imaging: II. Spatial memory tests

Innis, Nancy K.; Ossenkopp, Klaus‐Peter; Prato, Frank S.; Sestini, Edmund

doi:10.1016/0730-725x(86)91037-4

Cited by 38 publications

(15 citation statements)

References 10 publications

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“…The results of a number of other studies have also reported that exposure to stronger static and time-varying magnetic fields have no apparent effects on a variety of measures of learning and memory in laboratory rodents (reviews in Mather 1985;Innis et al 1986;Ossenkopp et al 1986). However, in those studies determinations of performance were made after, rather than during, exposure to the magnetic stimuli.…”

Section: Discussionmentioning

confidence: 68%

Brief exposure to 60 Hz magnetic fields improves sexually dimorphic spatial learning performance in the meadow vole, Microtus pennsylvanicus

1993

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1. This study examined spatial learning and memory in breeding adult male and female meadow voles, Microtus pennsylvanicus, and the effects of brief exposure to weak (0.1 mT or 1.0 Gauss rms) 60 Hz magnetic fields on their spatial performance.2. There were significant sex differences in the spatial performance of the polygynous meadow voles. Reproductive male voles displayed significantly better spatial learning and retention than reproductive females in a Morris water maze task, whereby individual voles had to learn and remember the location of a submerged hidden platform using extramaze visual cues. Males showed over 9 days of daily blocks of 4 trials both a faster rate and greater overall level of acquisition (shorter latency to find hidden platform) of the spatial task than did the females.3. Brief (maximum 5 min) exposure to 60 Hz magnetic fields during acquisition of the water maze task significantly enhanced the spatial performance of both the male and female meadow voles. Females showed a relatively greater facilitation of spatial acquisition and retention than did the males, resulting by day 9 in the elimination of sex differences in water maze performance. 4. The time-varying magnetic fields may be: (i) functioning as orientation cues and providing directional cues, and/or (ii) affecting neuromodulatory systems that are involved in the mediation of spatial learning and memory. Exposure to weak time-varying magnetic fields has been shown to attenuate the activity of endogenous opioid systems, enhance protein kinase C (PKC) activity, and alter calcium ion flux. These effects have been shown to affect spatial learning and memory and are consistent with an enhancement of water maze performance.

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Section: Discussionmentioning

confidence: 68%

Brief exposure to 60 Hz magnetic fields improves sexually dimorphic spatial learning performance in the meadow vole, Microtus pennsylvanicus

1993

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“…There is increasing evidence that high magnetic fields (>= 4 T) interact with the vestibular system of rodents and humans, although the mechanism of interaction is unknown. Magnetic field exposure under 2 T does not appear to be detectable by humans (Schenck, 1992; Winther et al, 1999) and has been reported to have no effect on a variety of behavioral tasks in rats (Innis et al, 1986; Messmer et al, 1987; Ossenkopp et al, 1986). Surveys of workers employed and within a 4 T MRI magnet (Schenck, 1992) or 9.4 T MRI magnet (Patel et al, 2008) reported sensations of vertigo, nausea, and illusions of movement that have been attributed to vestibular perturbations.…”

Section: Introductionmentioning

confidence: 98%

c-Fos induction by a 14T magnetic field in visceral and vestibular relays of the female rat brainstem is modulated by estradiol

et al. 2010

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There is increasing evidence that high magnetic fields interact with the vestibular system of humans and rodents. In rats, exposure to high magnetic fields of 7T or above induces locomotor circling and leads to a conditioned taste aversion if paired with a novel taste. Sex differences in the behavioral responses to magnetic field exposure have been found, such that female rats show more locomotor circling and enhanced conditioned taste aversion compared to male rats. To determine if estrogen modulates the neural response to high magnetic fields, c-Fos expression after 14T magnetic field exposure was compared in ovariectomized rats and ovariectomized rats with estradiol replacement. Compared to sham exposure, magnetic field exposure induced significantly more c-Fos positive cells in the nucleus of the solitary tract and the parabrachial, medial vestibular, prepositus, and supragenualis nuclei. Furthermore, there was a significant asymmetry in c-Fos induction between sides of the brainstem in several regions. In ovariectomized rats, there was more c-Fos expressed in the right side compared to left side in the locus coeruleus and parabrachial, superior vestibular, and supragenualis nuclei; less expression in the right compared to left side of the medial vestibular; and no asymmetry in the prepositus nucleus and the nucleus of the solitary tract. Chronic estradiol treatment modulated the neural response in some regions: less c-Fos was induced in the superior vestibular nucleus and locus coeruleus after estradiol replacement; estradiol treatment eliminated the asymmetry of c-Fos expression in the locus coeruleus and supragenualis nucleus, created an asymmetry in the prepositus nucleus and reversed the asymmetry in the parabrachial nucleus. These results suggest that ovarian steroids may mediate sex differences in the behavioral responses to magnetic field exposure at the level of visceral and vestibular nuclei of the brainstem.

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“…MF exposure under 2 T does not appear to be detectable by humans and has been reported to have no effect on a variety of behavioral tasks in rats (28,42,45,56,65). However, there have been reports of vertigo and nausea in humans between 4 T and 8.4 T using MRI machines, suggesting stimulation of visceral or sensory systems (29,56).…”

mentioning

confidence: 93%

“…conditioned taste aversion; locomotor circling; estrogen; progesterone ADVANCES IN MAGNETIC RESONANCE imaging (MRI) are leading to the development of more powerful MRI machines capable of producing higher-resolution images, but the sensory, neural, or somatic effects of high-strength static magnetic fields (MFs) on mammals and humans are virtually unexplored. MF exposure under 2 T does not appear to be detectable by humans and has been reported to have no effect on a variety of behavioral tasks in rats (28,42,45,56,65). However, there have been reports of vertigo and nausea in humans between 4 T and 8.4 T using MRI machines, suggesting stimulation of visceral or sensory systems (29, 56).…”

mentioning

confidence: 94%

Sex and estrous cycle differences in the behavioral effects of high-strength static magnetic fields: role of ovarian steroids

Cason¹,

DenBleyker²,

Ferrence³

et al. 2006

American Journal of Physiology-Regulatory, Integrative and Comp

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Advances in magnetic resonance imaging are driving the development of higher-resolution machines equipped with high-strength static magnetic fields (MFs). The behavioral effects of high-strength MFs are largely uncharacterized, although in male rats, exposure to 7 T or above induces locomotor circling and leads to a conditioned taste avoidance (CTA) if paired with a novel taste. Here, the effects of MFs on male and female rats were compared to determine whether there are sex differences in behavioral responses and whether these can be explained by ovarian steroid status. Rats were given 10-min access to a novel saccharin solution and then restrained within a 14-T magnet for 30 min. Locomotor activity after exposure was scored for circling and rearing. CTA extinction was measured with two-bottle preference tests. In experiment 1, males were compared with females across the estrous cycle after a single MF exposure. Females circled more and acquired a more persistent CTA than males; circling was highest on the day of estrus. In experiment 2, the effects of three MF exposures were compared among intact rats, ovariectomized females, and ovariectomized females with steroid replacement. Compared with intact rats, ovariectomy increased circling; estrogen replacement blocked the increase. Males acquired a stronger initial CTA but extinguished faster than intact or ovariectomized females. Thus the locomotor circling induced by MF exposure was increased in females and modulated by ovarian steroids across the estrous cycle and by hormone replacement. Furthermore, female rats acquired a more persistent CTA than male rats, which was not dependent on estrous phase or endogenous ovarian steroids.

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Behavioral effects of exposure to nuclear magnetic resonance imaging: II. Spatial memory tests

Cited by 38 publications

References 10 publications

Brief exposure to 60 Hz magnetic fields improves sexually dimorphic spatial learning performance in the meadow vole, Microtus pennsylvanicus

Brief exposure to 60 Hz magnetic fields improves sexually dimorphic spatial learning performance in the meadow vole, Microtus pennsylvanicus

c-Fos induction by a 14T magnetic field in visceral and vestibular relays of the female rat brainstem is modulated by estradiol

Sex and estrous cycle differences in the behavioral effects of high-strength static magnetic fields: role of ovarian steroids

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