Chaotic and stochastic dynamics of epileptiform-like activities in sclerotic hippocampus resected from patients with pharmacoresistant epilepsy.

The types of epileptiform activity occurring in the sclerotic hippocampus with highest incidence are interictal-like events (II) and periodic ictal spiking (PIS). These activities are classified according to their event rates, but it is still unclear if these rate differences are consequences of underlying physiological mechanisms. Identifying new and more specific information related to these two activities may bring insights to a better understanding about the epileptogenic process and new diagnosis. We applied Poincaré map analysis and Recurrence Quantification Analysis (RQA) onto 35 in vitro electrophysiological signals recorded from slices of 12 hippocampal tissues surgically resected from patients with pharmacoresistant temporal lobe epilepsy. These analyzes showed that the II activity is related to chaotic dynamics, whereas the PIS activity is related to deterministic periodic dynamics. Additionally, it indicates that their different rates are consequence of different endogenous dynamics. Finally, by using two computational models we were able to simulate the transition between II and PIS activities. The RQA was applied to different periods of these simulations to compare the recurrences between artificial and real signals, showing that different ranges of regularity-chaoticity can be directly associated with the generation of PIS and II activities.

Challenges in the treatment of a chronic disease: A study of narratives of people with juvenile myoclonic epilepsy.

PURPOSE: The purpose of this study was to explore how people with juvenile myoclonic epilepsy perceive the impact of treatment. METHODS: We conducted 14 interviews of participants with juvenile myoclonic epilepsy recruited with the support of the Brazilian Association of Epilepsy in 2018 in São Paulo. Thematic analysis was carried out by two investigators who independently coded the transcripts and reviewed the coding results to check for agreement. RESULTS: Participants' (n = 14, 8 female) mean age was 31.4 years (SD ± 8.3) and their onset of seizures occurred at mean age 13.4 (SD ± 2.9). The answers to the interview questions revealed the paths of participants through life as they dealt with difficulties and challenges. Three interrelated themes and seven sub-themes emerged from the answers of the participants: seizure control, impact of epilepsy and attitude of others. CONCLUSION: This investigation may be useful in providing insights for the interventions of health providers in caring for people with JME. Themes and sub-themes that emerged from this study are connected to important aspects of treatment that go beyond focusing solely on seizures.

Transcranial low-level laser therapy in an in vivo model of stroke: Relevance to the brain infarct, microglia activation and neuroinflammation.

Stroke is the main cause of death and functional disability. The available therapy affects only 5% of patients, and new therapeutic approaches have been constantly tested. Transcranial photobiomodulation (PBM) is promising for its neuroprotective effect on brain injuries. Thus, the present study investigated the PBM effects in an in vivo model of ischemic stroke induced by photothrombosis (PT). Five different groups of Wistar rats were submitted or not to a daily dose of fish oil or/and laser sessions for 2 months. The ischemia volume was evaluated by stereology; GFAP, Iba and NeuN by immunohistochemistry; TNF-α, IL-1ß, IL-6, IL-10 and TGF-ß by ELISA assay. PBM influenced both the lesion volume and the GFAP. Furthermore, PBM and Ω-3 or both reduced Iba RNAm. PBM reduced TNF-α, IL-1ß, IL-6, brain damage, neuroinflammation and microglial activation, and it increased astroglial activity in peri-lesioned region after stroke.

Different patterns of epileptiform-like activity are generated in the sclerotic hippocampus from patients with drug-resistant temporal lobe epilepsy.

Human hippocampal slice preparations from patients with temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS) are excellent material for the characterization of epileptiform-like activity. However, it is still unknown if hippocampal regions as cornu Ammonis (CA) 1, CA3 and CA4, generate population epileptiform-like activity. Here, we investigated epileptiform activities of the subiculum, CA1, CA2, CA3, CA4 (induced by elevation of extracellular potassium concentration) and the dentate gyrus (induced with hilar stimulation and elevation of potassium concentration) from sclerotic hippocampi of patients with drug-resistant TLE. Five types of epileptiform-like activity were observed: interictal-like events; periodic ictal spiking; seizure-like events; spreading depression-like events; tonic seizure-like events and no activity. Different susceptibilities to generate epileptiform activity among hippocampal regions were observed; the dentate gyrus was the most susceptible region followed by the subiculum, CA4, CA1, CA2 and CA3. The incidence of epileptiform activity pattern was associated with specific regions of the hippocampal formation. Moreover, it was observed that each region of the hippocampal formation exhibits frequency-specific ranges in each subfield of the sclerotic human tissue. In conclusion, this study demonstrates that epileptiform-like activity may be induced in different regions of the hippocampal formation, including regions that are severely affected by neuronal loss.