title: Temporal rearrangement of pre-ictal PTZ induced spike discharges by low frequency electrical stimulation to the amygdaloid complex.
abstract: BACKGROUND
  Epilepsy is a common neurological disease affecting over 40 million people worldwide. The foremost important challenge of epileptologists has been to control and predict the recurrent and spontaneous seizures of epileptic patients. The application of low frequency electrical stimulation (LFS) in deep brain structures has shown promising results in seizure control. However, the use of LFS as a probing strategy for seizure prediction, thus contributing to a closed loop solution, is still poorly explored.
  
  
  OBJECTIVE
  To improve seizure prediction by producing gradually increasing phase-locked pre-ictal electrographical responses, due to the short-term plastic changes in epileptogenic neural networks, thus behaving as a "programmed" surrogate marker.
  
  
  METHODS
  Urethane anesthetized rats were divided into 3 groups: the PTZ-noES group was injected with pentylenetetrazole (PTZ 4 mg/ml/min flow rate) i.v. without electrical stimulation (ES); the ES-noPTZ group received ES (0.5 Hz, 0.1 ms pulse width and 0.6 mA) to the amygdaloid complex and the PTZ + ES group received simultaneously i.v. PTZ infusion and ES. After each condition, electrographical parameters and c-Fos expression of regions of interest were evaluated.
  
  
  RESULTS
  Although the PTZ + ES group had no evident change in the sustained electrographic seizure onset, duration and/or frequency spectrum; c-Fos labeling showed a different expression pattern when compared to the PTZ-noES and ES-noPTZ. Also, PTZ + ES formed a gradually increasing evoked potential; confirming the strong coupling of reverberant neural networks induced by ES - phase locked to stimuli.
  
  
  CONCLUSIONS
  ES induces a detectable temporal rearrangement of pre-ictal activity, which has suggestive applicability to seizure prediction.
authors: Núcleo de Neurociências (NNC), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil; Centro de Tecnologia e Pesquisa em Magneto-Ressonância, Escola de Engenharia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil.
authors: Daniel Castro
authors: DC
authors: Medeiros
authors: Departamento de Engenharia Eletrônica - Escola de Engenharia - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil.
authors: Luciano Borges
authors: LB
authors: Oliveira
authors: Núcleo de Neurociências (NNC), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil.
authors: Flávio Afonso Gonçalves
authors: FA
authors: Mourão
authors: Núcleo de Neurociências (NNC), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil.
authors: Cristiane Perácio
authors: CP
authors: Bastos
authors: Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirao Preto, São Paulo CEP 14049-900, Brasil.
authors: Norberto Garcia
authors: NG
authors: Cairasco
authors: Núcleo de Neurociências (NNC), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil.
authors: Grace Schenatto
authors: GS
authors: Pereira
authors: Centro de Tecnologia e Pesquisa em Magneto-Ressonância, Escola de Engenharia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil; Departamento de Engenharia Eletrônica - Escola de Engenharia - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil.
authors: Eduardo Mazoni Andrade Marçal
authors: EM
authors: Mendes
authors: Núcleo de Neurociências (NNC), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil; Centro de Tecnologia e Pesquisa em Magneto-Ressonância, Escola de Engenharia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270-901, Brasil. Electronic address: mfdm@icb.ufmg.br.
authors: Márcio Flávio Dutra
authors: MF
authors: Moraes
mesh_terms: D000679:Amygdala / Q000378:metabolism / Q000503:physiopathology*; D000818:Animals; D004558:Electric Stimulation / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D008297:Male; D009415:Nerve Net / Q000378:metabolism / Q000503:physiopathology*; D009474:Neurons / Q000378:metabolism; D010433:Pentylenetetrazole; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D010433:Pentylenetetrazole
keywords: Epilepsy; Low frequency electric stimulation; Pentylenetetrazole; Phase-locking; Seizure prediction