Optical imaging of acute epileptic networks in mice

Abstract

Abstract. The potential of intrinsic optical imaging and resting-state analysis under anesthetized conditions as a tool to study brain networks associated with epileptic seizures is investigated. Using an acute model of epileptiform activity, the 4-aminopyridine model in live mice, we observe the changes in resting-state networks with the onset of seizure activity and in conditions of spiking activity. Resting-state networks identified before and after the onset of epileptiform activity show both decreased and increased homologous correlations, with a small dependence on seizure intensity. The observed changes are not uniform across the different hemodynamic measures, suggesting a potential decoupling between blood flow and metabolism in the low-frequency networks. This study supports the need for a more extensive investigation of epileptic networks including more than one independent hemodynamic measurement.

Interneurons contribute to the hemodynamic/metabolic response to epileptiform discharges

“…Since blocking GABA A receptors with picrotoxin reduces the blood flow response to sensory stimu- lation (Kocharyan et al 2008;Lecrux et al 2011), the CBF responses to EDs in our model are likely to be underestimated. Nevertheless, the correlation between INT firing and the CBF response could easily be measured by our procedure in epilepsy models that do not act directly on GABA transmission (Guevara et al 2013).…”

Brain hemodynamic response to somatosensory stimulation in Neuroligin-1 knockout mice

“…Moreover, it was also shown to attenuate hemodynamic responses (Franceschini et al, 2010;Takuwa et al, 2012). Alpha-chloralose anesthesia allows the largest hemodynamic response following sensory stimulation (Franceschini et al, 2010), and urethane anesthesia (with tracheotomy) also seems to importantly preserve hemodynamic function (Moldestad et al, 2009;Guevara et al, 2013). Alpha-chloralose was not approved for mice by our local Ethics Committee due to insufficient analgesic properties (Holzgrefe et al, 1987;Zuurbier et al, 2002).…”

Altered Functional Connectivity Following an Inflammatory White Matter Injury in the Newborn Rat: A High Spatial and Temporal Resolution Intrinsic Optical Imaging Study

“…Imaging was carried out according to previous rs-OIS studies in rodents (Guevara et al, 2013b,c; Bélanger et al, 2016). Briefly, multi-spectral rs-OIS (λ = 525, 590, 630 nm) was performed under anesthesia.…”

“…Regions of interest, also called seeds in the context of fc, were obtained from previous studies in the rodent brain that have identified a series of cortical regions that exhibit alterations in fc in several conditions, such as ischemic stroke (Bauer et al, 2014), epilepsy (Guevara et al, 2013b), arterial stiffness (Guevara et al, 2013c), cortical spreading depression (Li et al, 2012), and amyloid-β deposition (Bero et al, 2012). …”