Spike-induced cytoarchitectonic changes in epileptic human cortex are reduced via MAP2K inhibition

Interictal spikes are electroencephalographic discharges that occur at or near brain regions that produce epileptic seizures. While their role in generating seizures is not well understood, spikes have profound effects on cognition and behavior, depending on where and when they occur. We previously demonstrated that spiking areas of the human neocortex show sustained MAPK activation in superficial cortical layers I-III and are associated with microlesions in deeper cortical areas characterized by reduced neuronal nuclear protein (NeuN) staining and increased microglial infiltration. Based on these findings, we chose to investigate additional neuronal populations within microlesions, specifically inhibitory interneurons. Additionally, we hypothesized that spiking would be sufficient to induce similar cytoarchitectonic changes within the rat cortex and that inhibition of MAPK signaling, using a MAP2K inhibitor, would not only inhibit spike formation but also reduce these cytoarchitectonic..., 40 two-month-old male Sprague-Dawley rats were utilized for this study. Briefly, rats were anesthetized and 7 electrode holes were drilled through the skull (3 left and 3 right electrode holes located at the following locations relative to bregma: AP +4 mm, ML 3.5 mm; AP -1 mm, ML 3.5 mm; AP -6 mm, ML 3.5 mm; 1 reference electrode hole above the nasal sinus: AP +10.5 mm, ML 0.5 mm left). Before electrode screw placement, rats received an injection of either 1 uL of sterile PBS alone (sham rats) or 80 ng of tetanus toxin (TeNT rats) in 1 uL of sterile PBS into the left somatosensory cortex (corresponding to the site of the left middle electrode: AP -1 mm, ML 3.5 mm left, DV -1.5 mm). Epidural electrode screws were then placed, and rats were fitted with head cap apparatuses.
Beginning on postoperative day 5, electroencephalography (EEG) recordings were conducted every 5 days through postoperative day 35. From post-operative days 35-84, EEG recordings were conducted once weekly. After post..., EDF browser was used for data visualization and analysis.
R or RStudio can be used to open the RDA file., # Spike-induced cytoarchitectonic changes in the epileptic human cortex are reduced via MAP2K inhibition

---

## Description of the data and file structure

Variables in R Dataset (SpikeData_Cleaned_withRecTime.Rda):

* SpikeTimeSec: Identifies the time that a spike was observed on the EDF file, relative to the file start time.
* OspikeV: Maximum spike voltage (uV)
* Ldur2: Duration of the left half-spike (ms)
* Rdur2: Duration of the right half-spike (ms)
* Tdur2: Total spike duration (ms)
* OLslope2: Slope of the left half-spike
* ORslope2: Slope of the right half-spike
* OLamp2: Amplitude of the left half-spike (uV)
* ORamp2: Amplitude of the right half-spike (uV)
* CH: Corresponds to the electrode recording site. 1: right anterior electrode; 2: right middle electrode; 3: right posterior electrode; 4: left anterior electrode; 5: left middle electrode (site of TeNT or saline injection); 6: left posterior electrode
* Rat: Individual rat identification number
* ...