Diversity of LFPs Activated in Different Target Regions by a Common CA3 Input.
Identifying the pathways contributing to local field potential (LFP) events and oscillations is essential to determine whether synchronous interregional patterns indicate functional connectivity. Here, we studied experimentally and numerically how different target structures receiving input from a common population shape their LFPs. We focused on the bilateral CA3 that sends gamma-paced excitatory packages to the bilateral CA1, the lateral septum, and itself (recurrent input). The CA3-specific contribution was isolated from multisite LFPs in target regions using spatial discrimination techniques. We found strong modulation of LFPs by target-specific features, including the morphology and population arrangement of cells, the timing of CA3 inputs, volume conduction from nearby targets, and co-activated inhibition. Jointly they greatly affect the LFP amplitude, profile, and frequency characteristics. For instance, ipsilateral (Schaffer) LFPs occluded contralateral ones, and septal LFPs arise mostly from remote sources while local contribution from CA3 input was minor. In the CA3 itself, gamma waves have dual origin from local networks: in-phase excitatory and nearly antiphase inhibitory. Also, waves may have different duration and varying phase in different targets. These results indicate that to explore the cellular basis of LFPs and the functional connectivity between structures, besides identifying the origin population/s, target modifiers should be considered.
['Martín-Vázquez|Gonzalo|G|', 'Benito|Nuria|N|', 'Makarov|Valeri A|VA|', 'Herreras|Oscar|O|', 'Makarova|Julia|J|']
D000818:Animals D001640:Bicuculline D056547:CA1 Region, Hippocampal D056654:CA3 Region, Hippocampal D002408:Catheters, Indwelling D003198:Computer Simulation D004567:Electrodes, Implanted D005260:Female D007839:Functional Laterality D058787:GABA-A Receptor Antagonists D065818:Gamma Rhythm D008012:Lidocaine D008564:Membrane Potentials D008959:Models, Neurological D009434:Neural Pathways D009474:Neurons D017207:Rats, Sprague-Dawley D012686:Septal Nuclei D061567:Voltage-Gated Sodium Channel Blockers
CA3 local field potentials LFP biophysics gamma oscillations neuron models