US EPA

3420876 

Journal Article 

Differential responsiveness of the right parahippocampal region to electrical stimulation in fixed human brains: Implications for historical surgical stimulation studies? 

Rouleau, N; Persinger, MA 

2016 

Yes 

Epilepsy & Behavior
ISSN: 1525-5050 

60 

181-186 

English 

27208828 

10.1016/j.yebeh.2016.04.028 

WOS:000377992500030 

If structure dictates function within the living human brain, then the persistence of specific responses to weak electric currents in fixed, deceased brains could reflect "hardwired" properties. Different key structures from the left and right hemispheres of brains that had been fixed for over 20years with ethanol-formalin-acetic acid were stimulated with either 1-Hz, 7-Hz, 10-Hz, 20-Hz, or 30-Hz, sine-wave, square-wave, or pulsed currents while needle-recorded quantitative electroencephalographic responses were obtained. Differential responses occurred only within the right hippocampus and parahippocampal gyrus. The right hippocampus displayed frequency-independent increases in gamma power relative to the left hemispheric homologue. The parahippocampal region responded exclusively to 7-Hz pulsed currents with wideband (8-30Hz) power. These profiles are consistent with dynamic connections associated with memory and consciousness and may partially explain the interactions resultant of pulse type and hemisphere for experiential elicitations during the golden age of surgical stimulations. The results also indicate that there may be an essential "hardwiring" within the human brain that is maintained for decades when it is fixed appropriately. 

Fixed human brain; Parahippocampus; Hippocampus; Theta-gamma activity; Surgical stimulation; Hardwired