Journal: Neurobiology of disease

Article Title: Hippocampal seizures differentially modulate locus coeruleus activity and result in consistent time-locked release of noradrenaline in rat hippocampus.

doi: 10.1016/j.nbd.2023.106355

Figure Lengend Snippet: Fig. 2. Electrically evoked hippocampal seizures are associated with changes in firing rates of locus coeruleus (LC) neurons. Hippocampal seizures were induced with 10s tetanic burst stimuli delivered in the perforant path, denoted with red dashed lines. A) Hippocampal local field potential (LFP) trace, B) a spectrogram of the hippocampal LFP, C) and D) example of LC neurons displaying increased firing during hippocampal seizures, E) and F) example of a LC neurons showing decreased firing during hippocampal seizures, G) normalized changes in firing rates of the LC neurons identified based on single channel tungsten needle recordings and H) normalized changes in firing rates of neurons identified from multi-channel probe recordings. In G) and H), firing rates during hippocampal seizures have been normalized to the mean firing rate of the minute before seizure induction. I) Raster plots of all LC neurons in relation to consecutive seizures. J) Raster plots of all neurons not meeting the criteria as LC neurons. Neurons are ordered according to the change in firing rate during seizure 1. Red dashed lines denote the start and end of perforant path stimulation. Note that raster plots are not provided for a third seizure since only two seizures were evoked for some experiments. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Article Snippet: Subsequently, a number of hippocampal seizures were evoked with 10 s tetanic trains of electrical stimulation (20 Hz, 0.2 ms bipolar square wave pulses, DS4 Bi-Phasic Stimulator, Digitimer, USA).

Techniques:

Journal: Neurobiology of disease

Article Title: Hippocampal seizures differentially modulate locus coeruleus activity and result in consistent time-locked release of noradrenaline in rat hippocampus.

doi: 10.1016/j.nbd.2023.106355

Figure Lengend Snippet: Fig. 8. Changes in noradrenergic transmission in the hippocampus were assessed using the fluorescent sensor for noradrenaline GRABNE2m in combination with fiber photometry. A-C) Perforant path stimulation induced seizures (red dashed lines) were associated with an increase in GRABNE2m fluorescence. Similar outcomes were observed in anesthetized (D) and awake rats (E), * indicates the peak response in fluorescence for one animal after a seizure. Changes were observed to be highly significant both at a group level and individual level. Changes in GRABNE2m fluorescence were further found to be correlated to changes in hippocampal LFP amplitude when cross correlating 1-s amplitude bins over the 50-s period following electrical stimulation. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Article Snippet: Subsequently, a number of hippocampal seizures were evoked with 10 s tetanic trains of electrical stimulation (20 Hz, 0.2 ms bipolar square wave pulses, DS4 Bi-Phasic Stimulator, Digitimer, USA).

Techniques: Transmission Assay, Fluorescence