Article Figures & Data
Figures
- Fig. 1.
Tight-circling activity induced by magnetic field exposure. Rats were restrained for 30 min within the bore of a 14 T magnet in either head-up orientation (A) or head-down orientation (B). On release from restraint, rats oriented head-up circled counterclockwise, whereas rats oriented head-down circled clockwise.
- Fig. 2.
CTAs induced by a single pairing of G+S intake with a 30 min restraint within magnetic fields of different strengths. For the 24 hr two bottle preference test after the pairing of G+S with magnetic exposure (A), a significant CTA against G+S was observed only after pairing with 14 T exposure. The CTA extinguished after 3 d of two bottle preference tests (B). *p < 0.05 versus 0 T (sham) exposure. Data for 9.4 T exposure are replotted from Nolte et al. (1998).
- Fig. 3.
CTAs induced by a single pairing of G+S intake with restraint within 14 T magnetic fields for 0–30 min. Significant CTA was observed after ≥1 min of exposure to the magnetic field on the first 24 hr two bottle preference test (A); the CTAs persisted for several days of preference testing (B). *p < 0.05 versus 0 min exposure.
- Fig. 4.
Acquisition of CTAs across three pairings of G+S with 30 min restraint within 7, 9.4, or 14 T magnetic fields. Intake during 10 min access to G+S was not different between sham- and 7 T-exposed rats across the 3 conditioning days (A). Rats exposed to 9.4 T decreased intake compared with sham-exposed rats on the third day of conditioning (i.e., after two pairings; B). Rats exposed to 14 T decreased intake on the second day of conditioning (i.e., after one pairing;C). *p < 0.05 versus sham-exposed rats. Data for 9.4 T exposure are replotted from Nolte et al. (1998).
- Fig. 5.
CTAs induced by three pairings of G+S intake with restraint within 7, 9.4, or 14 T magnetic fields for 0–30 min. Significant CTAs were observed in all magnet-exposed rats on the first 24 hr two bottle preference test (A). Over subsequent 24 hr two bottle test days, the CTA of 7 T-exposed rats extinguished on the second day (B), whereas the CTAs of 9.4 T- and 14 T-exposed rats persisted for 8 d of preference testing (C, D). *p < 0.05 versus sham-exposed rats; †p < 0.05 versus 7 T-exposed rats. Data for 9.4 T exposure are replotted from Nolte et al. (1998).
- Fig. 6.
CTAs induced by a single pairing of G+S with 14 T restraint in head-up or head-down orientations. After 10 min of access to G+S, rats were restrained in either a head-up orientation (black squares) or head-down orientation (black circles) for 30 min within the 14 T magnetic field. Although rats circled in opposite directions on release from restraint (with head-up rats circling counterclockwise and head-down rats circling clockwise), there was little difference in the CTA acquisition of the two groups. Control rats were sham-exposed while head-down for 30 min (white circles).
Tables
Field Duration Number of rats % Circling Mean circles % Rearing Mean rears Experiments 1a and 2 0 T 30 min 22 5 1 91 3.8 ± 0.5 7 T 30 min 17 47 2.4 ± 0.6* 59 2.8 ± 0.9* 14 T 30 min 17 71 2.6 ± 0.4* 0 0*† Experiment 1b 14 T 0 min 6 0 0 ± 0 100 4.8 ± 0.8 14 T 1 min 6 0 0 ± 0 100 1.8 ± 0.7* 14 T 5 min 8 50 5.0 ± 2.5 67 2.3 ± 0.5* 14 T 10 min 14 57 2.9 ± 0.7 43 2.2 ± 0.5* 14 T 20 min 8 63 2.8 ± 0.5 13 1* 14 T 30 min 17 71 2.6 ± 0.4 0 0* Experiment 3 0 T Down 30 min 12 0 0 83 4.9 ± 1.1 14 T Down 30 min 15 73 6.1 ± 2.7 33 2.0 ± 0.3* 14 T Up 30 min 13 77 8.4 ± 2.5 54 1.6 ± 0.3* Locomotor activity of rats after magnetic field exposure was scored for tight circling and rearing by a blind observer from videotape records. Rats were sham exposed (0 T) or exposed to 7 or 14 T magnetic fields for 0–30 min. Shown are the number of rats tested, the percentage of rats displaying circling or rearing, and the mean ± SEM number of circles or rears counted for those rats that showed any circling or rearing (i.e. non-zero means). In experiments 1a and 2, rats were exposed head-up to a 7 or 14 T magnetic field for 30 min; both exposures induced circling and suppressed rearing. In experiment 1b, rats were exposed head-up to 14 T for 0–30 min; significant circling was induced by ≥5 min of exposure, and rearing was significantly suppressed after ≥10 min of exposure. In experiment 3, rats were restrained in either the head-up or head-down orientation within a 14 T magnetic field for 30 min. Circling was induced and rearing was suppressed in both groups, but the direction of circling depended on the rats' orientation within the field (Fig. 1).
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