Modification of Semantic Memory in Normal Subjects by Application Across the Temporal Lobes of a Weak (1 Microt) Magnetic Field Structure that Promotes Long-Term Potentiation in Hippocampal Slices

Abstract

Normal, right-handed human volunteers listened to a 5-min story and were then exposed to 15 min (3 successive segments of 5 min on/5 min off) of magnetic pulses (1 microT; 10 mG) whose temporal structure has been shown to enhance long-term potentiation (LTP) in hippocampal slices. There were four conditions: no stimulation, bilateral stimulation (across both temporoparietal regions), primary stimulation of the left temporoparietal lobes or primary stimulation of the right temporoparietal lobes. Reconstructions of the story were completed by the same subjects within 30 min (intermediate memory) and about 10 days (long-term memory) later. The strongest effect size (25% of the variance was accommodated) was due to the approximately two fold increase in the numbers of accurate details for the long-term memories for subjects who had received the left hemispheric stimulation. These results suggest that contemporary technology may have the capability to access fundamental algorithms of the neuronal activity associated with declarative memory.

Key Words:

• Long-term potentiation
• Electromagnetic fields
• Hemisphere
• Semantic memory
• Recall
• Temporal lobes
• Human