title: Spatial modules of coherent activity in pathway-specific LFPs in the hippocampus reflect topology and different modes of presynaptic synchronization.
abstract: Ongoing network activity often manifests as irregular fluctuations in local field potentials (LFPs), a complex mixture of multicellular synaptic currents of varying locations and extensions. Among other conditions, for synchronously firing presynaptic units to generate sizable postsynaptic LFPs, their axonal territories should overlap. We have taken advantage of anatomical regularity of the rat hippocampus and combined multiple linear recordings and spatial discrimination techniques to separate pathway-specific LFPs with enough spatial resolution to discriminate postsynaptic regions of varying activation, and to investigate their presynaptic origin, chemical nature, and spatial extension. We identified 6 main excitatory and inhibitory LFP generators with different synaptic territories in principal cells and hippocampal subfields matching anatomical pathways. Some recognized pathways did not contribute notably to LFPs. Each showed different septo-temporal spatial modules over which the field potential fluctuations were synchronous. These modules were explained by either the strong overlap of synaptic territories of coactivated afferent neurons (e.g., CA3 clusters for CA1 Schaffer LFPs), or widespread coalescence of postsynaptic territories (granule cell somatic inhibition). We also show evidence that distinct modes of afferent synchronization generate stereotyped spatial patterns of synchronous LFPs in one pathway. Thus, studying spatial coherence of pathway-specific LFPs provides remote access to the dynamics of afferent populations.
authors: Department of Systems Neuroscience, Cajal Institute, CSIC, Madrid 28002, Spain and.
authors: N
authors: N
authors: Benito
authors: Department of Systems Neuroscience, Cajal Institute, CSIC, Madrid 28002, Spain and.
authors: A
authors: A
authors: Fernández-Ruiz
authors: Department of Applied Mathematics, Faculty of Mathematics, Universidad Complutense de Madrid, Madrid 28040, Spain.
authors: V A
authors: VA
authors: Makarov
authors: Department of Systems Neuroscience, Cajal Institute, CSIC, Madrid 28002, Spain and.
authors: J
authors: J
authors: Makarova
authors: Department of Systems Neuroscience, Cajal Institute, CSIC, Madrid 28002, Spain and.
authors: A
authors: A
authors: Korovaichuk
authors: Department of Systems Neuroscience, Cajal Institute, CSIC, Madrid 28002, Spain and.
authors: O
authors: O
authors: Herreras
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D007839:Functional Laterality; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology* / Q000502:physiology; D008959:Models, Neurological; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D019580:Perforant Pathway / Q000502:physiology; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018691:Excitatory Amino Acid Antagonists; D058787:GABA-A Receptor Antagonists; D011810:Quinoxalines; C056723:FG 9041; D001640:Bicuculline
keywords: LFP generators; correlated activity; independent component analysis; ongoing activity; spatial modules