Posttraumatic epilepsy

Post-traumatic epilepsy following fluid percussion injury in the rat.

D'Ambrosio R, Fairbanks JP, Fender JS, Born DE, Doyle DL, Miller JW., Brain. 2003 Nov 7 [Epub ahead of print]

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This work demonstrated for the first time that a single event of fluid percussion injury, a clinically relevant model of traumatic brain injury, is sufficient to induce posttraumatic epilepsy in the rat. Epilepsy following FPI emerges after a silent period and is characterized by partial seizures. This in vivo rodent model of posttraumatic epilepsy lends itself to both physiological and preclinical studies. The model reproduces many of the features of human PTE. The process of identifying specific epileptogenic mechanisms, and discovering the first antiepileptogenic agents, and new antiepileptics, will be advanced by its use.

Posttraumatic epilepsy is characterized by partial seizures. (Inset top, left) Schematic of the locations of the five epidural electrodes (filled circles) and of the injury site (hollow circle) in respect to the rat skull. From top to bottom, about 1.5 minutes of continuous electrocorticography (ECoG) from a posttraumatic rat, 2.5 months after severe lateral FPI, are shown. Frequent epileptiform events were recorded while the rat was fully awake and engaged in exploratory behavior. ECoG bursts were accompanied by pauses in ongoing behavior. Asterisks indicate partial epileptiform events all originating from the peri-lesion neocortical area. ECoG calibration bars are on the left. Dotted box highlights a typical grade 2 event. Bottom, middle inset) a grade 2 event at higher temporal resolution displaying its partial nature. Horizontal brackets delimit three areas of the top ECoG trace (channel 4-5) sampled for FFT analysis. Inset bottom, right) FFT analysis of three areas of the ECoG trace occurred immediately before, during and immediately after the epileptiform burst highlighted by the dotted box. FFT1 demonstrates the frequency components of the baseline ECoG immediately before the epileptic burst (1-9Hz). FFT 2 demonstrates the frequency components (5-30 Hz) during the epileptic burst, and the dramatic increase in the contribution of higher frequencies. FFT3 demonstrates the frequency components of the ECoG immediately after the epileptic burst. Note the disappearance of the theta activity at 7Hz immediately after the burst indicating post-ictal depression.