Pretraining Exposure to Physiologically Patterned Electromagnetic Stimulation atTenuates Fear-Conditioned Analgesia

Electromagnetic field enhanced flow state: Insights from electrophysiological measures, self-reported experiences, and gameplay

The intersection of neuroscience and technology hinges on the development of wearable devices and electrodes that can augment brain networks to improve cognitive capabilities such as learning and concentration. The capacity to enhance networks associated with these functions above baseline capabilities, holds the potential to benefit numerous individuals. The purpose of this study was to determine if electromagnetic field exposure modeled from physiological data would increase instances of flow in participants playing a computer game. The flow state refers to a subjective state of optimal performance experienced by individuals during a variety of tasks. For this study, participants (n = 39, 18-65 years, nfemale = 20) played the arcade game Snake for two ten-minute periods (each with a ten-minute rest period immediately following). For one of the trials, an electromagnetic field was applied bilaterally to the temporal lobes, with the other serving as the control. Brain activity was measured using quantitative electroencephalography, flow experience was measured using the Flow Short Scale and game play scores were also recorded. Results showed deceased beta 1 (12-16 Hz) activity in the left cuneus [t = 4.650, p < 0.01] and left precuneus [t = 4.603, p < 0.01], left posterior cingulate [t = 4.521, p < 0.05], insula [t = 4.234, p < 0.05], and parahippocampal gyrus [t = 4.113, p < 0.05] for trials when the field was active, compared to controls during rest periods. Results from the Flow Short Scale showed a statistically significant difference in mean "concentration ease" scores across electromagnetic field conditions, irrespective of difficulty [t = 2.131, p < 0.05]. In the EMF exposure trials, there was no discernible experience effect; participants with prior experience in the game Snake did not exhibit significantly better performance compared to those without prior experience. This anticipated effect was observed in control conditions. The comparable performance observed between novices and experienced players in the EMF condition indicate a noteworthy learning curve for novices. In all, these results provide evidence supporting the ability of EMF patterned from amygdaloid firing (6-20 Hz) to elicit neurological correlates of flow in brain regions previously reported in the literature, facilitate concentration, and subtly improve game scores. The possibility for wearable devices to support learning, concentration, and focus are discussed.

Can the 8-Coil Shakti Alter Subjective Emotional Experience? A Randomized, Placebo-Controlled Study

At present, a commercially available device (the 8-coil Shakti) claims to produce weak and complex magnetic fields that alter neurobiological processes. The effects of the Shakti on emotional responses to photographs that varied on emotional valence were investigated. Participants ( N = 37) were exposed to either 30 min. of magnetic fields or a sham condition and rated their emotional reactions to a set of 54 color photographs. Although participants indicated significantly different emotional responses to images with distinct emotional valences, exposure to magnetic fields did not affect these responses, nor significantly interact with image emotional valence. Although the device's “amygdala signal” had no effect on the emotive response to images in this study, additional investigations examining the effects of weak and complex magnetic fields on various aspects of perception and cognition are warranted.

BRIEF EXPOSURES TO THETA-BURST MAGNETIC FIELDS IMPAIR THE CONSOLIDATION OF FOOD-INDUCED CONDITIONED PLACE PREFERENCE

Theta-burst magnetic fields (1 microT) designed to mimic electrical stimuli employed in vitro to affect long-term potentiation have been previously shown to impair the acquisition of conditioned fear. In the current study, the authors were interested in investigating whether similar magnetic fields could affect the consolidation of food-induced conditioned place preference. Fourteen male Wistar rats were exposed to a theta-burst magnetic field (1 s pulse of 5 trains of an LTP-evoking pattern) continuously or with either a 5 s or 10 s interstimulus interval for 15 min immediately following 6 daily conditioning trials (15 min/day) in a place preference apparatus. Testing demonstrated the durations in the food-paired chamber was significantly shorter for all of the magnetic field-exposed groups compared to the sham-exposed group (they remained for longer periods in the food-paired chamber, typical of normal rats). In addition, the group exposed continuously to the LTP-magnetic field (1-ms interstimulus duration) displayed the least time in the food-paired chamber. The treatments explained 80% of the variance in durations within the experimental setting. These results suggest that exposures to theta-burst magnetic fields elicit amnesic effects for contextual stimuli.

Behavioral changes with brief exposures to weak magnetic fields patterned to stimulate long-term potentiation

Brief whole body exposures of rats to weak (1 microT) complex magnetic fields whose patterns induce long term potential (LTP) when applied as electric current to hippocampal slices produced powerful behavioral changes. Rats exposed for 30 min before but not 30 min after hourly training sessions for spatial memory displayed impairments comparable to those elicited by complete electrode-induced saturation of hippocampal activity. Exposure to the same LTP-patterned magnetic fields after weaning during the induction of limbic seizures produced diminished learning of conditioned contextual fear during adulthood. However exposure to magnetic fields designed to simulate a "virtual" hippocampal state during acquisition of a timed inhibitory task (DRL) facilitated performance. These results show that physiologically-patterned magnetic fields can produce dramatic changes in behavior when they are applied during states associated with marked synaptic plasticity.

Conditioned taste aversion is not disrupted in rats exposed to weak, complex magnetic fields during the CS-UCS interval

40 normal male Wistar rats were trained for 8 successive days to consume water ad libitum during once-daily 20-min. sessions. On the following day (training day) the rats were presented with a novel solution of 10% sucrose for 20 min. followed by a single exposure for 2 hr. to one of two weak (200 to 500 nanoTesla) complex magnetic fields or to sham-field conditions. The patterns of the two magnetic fields and the durations of their repeated presentations (interstimulus interval) were designed to be resonant with the intrinsic firing of hippocampal pyramidal and solitary neurons, respectively. Immediately after the applications of the fields one-half the number of rats were injected with lithium to evoke gastrointestinal malaise. Although on the test day, three days later, rats previously injected with the lithium exhibited the usual robust reduction in the consumption of sucrose compared to the training day, there were no statistically significant differences between field-exposed and sham-field groups for these ratios. We conclude that a 2-hr. exposure to weak magnetic fields designed to simulate the pattern of two structures likely involved with conditioned taste aversion between the conditioned stimulus and the unconditioned stimulus did not affect this behavior.

Ketamine Prevents Learning Impairment When Administered Immediately after Status Epilepticus Onset

Permanent cognitive impairment is common following status epilepticus (SE) in both humans and animals. We examined the effect of the NMDA antagonist ketamine administered after SE onset on two forms of associative learning in the rat: conditioned taste aversion and fear-conditioned analgesia. Following the onset of lithium/pilocarpine-induced SE, rats were administered either ketamine (100 mg/kg) or acepromazine (25 mg/kg). Acepromazine-treated animals show marked deficits in both learning measures at 1 month after SE. In contrast, ketamine-treated and nonepileptic control animals did not differ in performance for either task. Although studies have shown that ketamine is ineffective at controlling electrographic seizures early in SE, these results are consistent with previous studies showing that ketamine can preserve learning proficiency if administered shortly after seizure onset. As a clinically available drug, ketamine may prove useful in the treatment of SE when combined with conventional antiepileptic strategies.

Experimental production of illusory (false) memories in reconstructions of narratives: effect size and potential mediation by right hemispheric stimulation from complex, weak magnetic fields

This experiment was designed to discern the proportion of false, inferential and verbatim memories that would be included in the reconstruction, one week later, of a 5 min narrative containing ambiguous but emotional content about a little boy. After 48 subjects were administered Spiegel's Hypnosis Induction Profile, they listened to the narrative, were exposed to one of four applications of transcerebral weak, complex magnetic fields for 30 min and then given either an accurate or inaccurate short summary of the story. One week later the group who received the erroneous summary reported more false memories about the original story than did the reference group; this treatment accommodated about 40% of the variance in numbers of false memories. Only an indicator of electrical lability within the temporal lobes (but not hypnotizability) was strongly associated with the numbers of inferential memories but not the numbers of false memories. The group that received transcerebral stimulation over the right hemisphere by a complex magnetic field and the erroneous summary reported three times the numbers of false memories compared to the other groups. Whereas verbatim memories showed a strong primacy effect inferential memories exhibited a strong recency effect (eta(2) =.66).

Geophysical variables and behavior: XCI. Ambulatory behavior in rats following prenatal exposures to complex magnetic fields designed to interact with genetic expression

A total of 45 litters were exposed during their entire prenatal development to one of two complex patterns of magnetic fields whose strengths varied within one of four intensity ranges between 10 nT and 1,000 nT or to sham-field conditions. The litters exposed to the most complex pattern, composed of 50 200-msec. presentations of different pulses for 10 sec. every 50 sec., displayed more ambulation in an open field at 21 days of age than the litters that had been exposed continuously to a repetitive frequency-modulated field or to sham-field conditions. This treatment explained 25% of the variance in the numbers of squares traversed. The results suggest that complexity of the applied magnetic field during prenatal development may be more important than intensity for permanently affecting neuronal organization and behavior.

Application timing of complex magnetic fields delineates windows of posttraining-pretesting vulnerability for spatial and motivational behaviors in rats

Male Wistar rats were trained in a two-session-per-day, non-matching-to-sample radial maze task. During the 2 hr interval between training sessions and testing sessions subjects were exposed for 60 min to either sham fields or to a low intensity (200 to 500 nT) electromagnetic (EM) complex pattern whose electrical (current) equivalent has been shown to elicit long-term potentiation (LTP) in hippocampal slices. This pattern was applied either immediately following the training sessions or immediately antecedent to the testing sessions. Exposures to the experimental field immediately following the training session were associated with an impairment in spatial memory as inferred by increased commissions of reference errors. Exposures immediately prior to the testing session were associated with decreased motivation as inferred by a reduction in speed of responding. These results suggest that the timing of the presentation of patterned magnetic fields may differentially affect the representations of habit strength and drive within the consolidating memory trace.