Spatial contribution of hippocampal BOLD activation in high-resolution fMRI
Résumé
While the vascular origin of the BOLD-fMRI signal is established, the exact neurovascular coupling
events contributing to this signal are still incompletely understood. Furthermore, the hippocampal
spatial properties of the BOLD activation are not elucidated, although electrophysiology approaches
have already revealed the precise spatial patterns of neural activity. High magnetic feld fMRI ofers
improved contrast and allows for a better correlation with the underlying neuronal activity because
of the increased contribution to the BOLD signal of small blood vessels. Here, we take advantage of
these two benefts to investigate the spatial characteristics of the hippocampal activation in a rat model
before and after changing the hippocampal plasticity by long-term potentiation (LTP). We found that
the hippocampal BOLD signals evoked by electrical stimulation at the perforant pathway increased
more at the radiatum layer of the hippocampal CA1 region than at the pyramidal cell layer. The return
to the baseline of the hippocampal BOLD activation was prolonged after LTP induction compared with
that before most likely due vascular or neurovascular coupling changes. Based on these results, we
conclude that high resolution BOLD-fMRI allows the segregation of hippocampal subfelds probably
based on their underlying vascular or neurovascular coupling features.
Domaines
Sciences du Vivant [q-bio]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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