TY  - JOUR
AU  - Arboit, Alberto
AU  - Ku, Shih-Pi
AU  - Krautwald, Karla
AU  - Angenstein, Frank
TI  - Brief neuronal afterdischarges in the rat hippocampus lead to transient changes in oscillatory activity and to a very long-lasting decline in BOLD signals without inducing a hypoxic state.
JO  - NeuroImage
VL  - 245
SN  - 1053-8119
CY  - Orlando, Fla.
PB  - Academic Press
M1  - DZNE-2022-00424
SP  - 118769
PY  - 2021
AB  - The effects of hippocampal neuronal afterdischarges (nAD) on hemodynamic parameters, such as blood-oxygen-level-dependent (BOLD) signals) and local cerebral blood volume (CBV) changes, as well as neuronal activity and metabolic parameters in the dentate gyrus, was investigated in rats by combining in vivo electrophysiology with functional magnetic resonance imaging (fMRI) or 1H-nuclear magnetic resonance spectroscopy (1H-NMRS). Brief electrical high-frequency pulse-burst stimulation of the right perforant pathway triggered nAD, a seizure-like activity, in the right dentate gyrus with a high incidence, a phenomenon that in turn caused a sustained decrease in BOLD signals for more than 30 min. The decrease was associated with a reduction in CBV but not with signs of hypoxic metabolism. nAD also triggered transient changes mainly in the low gamma frequency band that recovered within 20 min, so that the longer-lasting altered hemodynamics reflected a switch in blood supply rather than transient changes in ongoing neuronal activity. Even in the presence of reduced baseline BOLD signals, neurovascular coupling mechanisms remained intact, making long-lasting vasospasm unlikely. Subsequently generated nAD did not further alter the baseline BOLD signals. Similarly, nAD did not alter baseline BOLD signals when acetaminophen was previously administered, because acetaminophen alone had already caused a similar decrease in baseline BOLD signals as observed after the first nAD. Thus, at least two different blood supply states exist for the hippocampus, one low and one high, with both states allowing similar neuronal activity. Both acetaminophen and nAD switch from the high to the low blood supply state. As a result, the hemodynamic response function to an identical stimulus differed after nAD or acetaminophen, although the triggered neuronal activity was similar.
KW  - Animals
KW  - Brain Waves: drug effects
KW  - Brain Waves: physiology
KW  - Disease Models, Animal
KW  - Electrocorticography
KW  - Hippocampus: drug effects
KW  - Hippocampus: physiology
KW  - Magnetic Resonance Imaging
KW  - Male
KW  - Neuroimaging
KW  - Neurovascular Coupling: drug effects
KW  - Neurovascular Coupling: physiology
KW  - Proton Magnetic Resonance Spectroscopy
KW  - Rats
KW  - Rats, Wistar
KW  - Seizures: metabolism
KW  - Seizures: physiopathology
KW  - 1H-NMR spectroscopy (Other)
KW  - Electrophysiology (Other)
KW  - Gamma oscillations (Other)
KW  - Negative BOLD (Other)
KW  - Postictal state (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:34861394
DO  - DOI:10.1016/j.neuroimage.2021.118769
UR  - https://pub.dzne.de/record/163678
ER  -