JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 81: 159-173, 1999;
0022-3077/99 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Jacobs, K. M.
Right arrow Articles by Prince, D. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Jacobs, K. M.
Right arrow Articles by Prince, D. A.

The Journal of Neurophysiology Vol. 81 No. 1 January 1999, pp. 159-173
Copyright ©1999 The American Physiological Society

Focal Epileptogenesis in a Rat Model of Polymicrogyria

Kimberle M. Jacobs, Bryan J. Hwang, and David A. Prince

Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, California 94305

Jacobs, Kimberle M., Bryan J. Hwang, and David A. Prince. Focal epileptogenesis in a rat model of polymicrogyria. J. Neurophysiol. 81: 159-173, 1999. Polymicrogyria, a developmental cortical malformation associated with epilepsy, can be modeled in rats with a transcortical freeze lesion on the day of birth (P0) or P1. We have used field potential recordings to characterize the incidence, propagation patterns, and distribution of epileptiform activity in slices from rats with experimental microgyri. Interictal-like epileptiform activity was evoked in slices from 85% of freeze-lesioned rats aged P12-P118. These data show age-specific properties of epileptogenesis, including: a delay in onset, a decrease in the incidence of epileptiform activity in rats >P40 that was specific to those lesioned on P0 as opposed to P1, and a shift in the likely site of initiation to areas further from the microgyrus in mature animals. Several observations suggest that the area adjacent to the microgyrus, which appears histologically normal in Nissl stains, contains the necessary epileptogenic neuronal circuits: 1) in 78% of slices, epileptiform activity could be evoked only from a focal zone adjacent to the microgyrus (paramicrogyral zone) and not within the microgyrus proper; 2) epileptiform activity consistently originated from a particular site within this paramicrogyral zone, independent of the location of the stimulating electrode, suggesting that the generator is outside of the microgyrus; 3) evoked epileptiform activities in the paramicrogyral cortex were unaltered after separation of this zone from the microgyrus with a transcortical cut; and 4) the short-latency graded field potential evoked in the paramicrogyral zone contained an additional negativity not seen in control slices. The epileptiform activity was blocked reversibly by N-methyl-D-aspartate receptor antagonists in slices from mature as well as immature freeze-lesioned rats. These results suggest that aberrant synaptic connectivity develops in rat cortex surrounding the microgyrus and produces a focal epileptogenic zone whose capacity to generate epileptiform activities does not depend on connections with the malformation itself. We hypothesize that afferents, originating from cortical and extracortical sites, lose their targets in the region of the malformation and make appropriate laminar contacts in the cortex adjacent to the malformation, creating an overabundance of excitatory input to this cortical zone. Increased excitatory feedback onto specific cortical elements may be one factor involved in epileptogenesis in this model of a cortical malformation.




This article has been cited by other articles:


Home page
 J. Neurophysiol.Home page
A. Zsombok and K. M. Jacobs
Postsynaptic Currents Prior to Onset of Epileptiform Activity in Rat Microgyria
J Neurophysiol, July 1, 2007; 98(1): 178 - 186.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
M. E. Calcagnotto and S. C. Baraban
Prolonged NMDA-Mediated Responses, Altered Ifenprodil Sensitivity, and Epileptiform-Like Events in the Malformed Hippocampus of Methylazoxymethanol Exposed Rats
J Neurophysiol, July 1, 2005; 94(1): 153 - 162.
[Abstract] [Full Text] [PDF]

Home page
 NeurologyHome page
E. Kobayashi, A. P. Bagshaw, A. Jansen, F. Andermann, E. Andermann, J. Gotman, and F. Dubeau
Intrinsic epileptogenicity in polymicrogyric cortex suggested by EEG-fMRI BOLD responses
Neurology, April 12, 2005; 64(7): 1263 - 1266.
[Abstract] [Full Text] [PDF]

Home page
 J Child NeurolHome page
G. H. Mochida
Topical Review: Cortical Malformation and Pediatric Epilepsy: A Molecular Genetic Approach
J Child Neurol, April 1, 2005; 20(4): 300 - 303.
[Abstract] [PDF]

Home page
 J. Neurophysiol.Home page
K. M. Jacobs and D. A. Prince
Excitatory and Inhibitory Postsynaptic Currents in a Rat Model of Epileptogenic Microgyria
J Neurophysiol, February 1, 2005; 93(2): 687 - 696.
[Abstract] [Full Text] [PDF]

Home page
 Cereb CortexHome page
O. Peters, C. Redecker, G. Hagemann, C. Bruehl, H. J. Luhmann, and O. W. Witte
Impaired Synaptic Plasticity in the Surround of Perinatally Aquired Dysplasia in Rat Cerebral Cortex
Cereb Cortex, October 1, 2004; 14(10): 1081 - 1087.
[Abstract] [Full Text] [PDF]

Home page
 J Child NeurolHome page
G. H. Mochida
Topical Review: Cortical Malformation and Pediatric Epilepsy: A Molecular Genetic Approach
J Child Neurol, March 1, 2004; 19(3): 300 - 303.
[Abstract] [PDF]

Home page
 Behav Cogn Neurosci RevHome page
R. H. Fitch and P. Tallal
Neural Mechanisms of Language-Based Learning Impairments: Insights from Human Populations and Animal Models
Behav Cogn Neurosci Rev, September 1, 2003; 2(3): 155 - 178.
[Abstract] [PDF]

Home page
 NeurologyHome page
C. Juhasz, D.C. Chugani, O. Muzik, A. Shah, E. Asano, T.J. Mangner, P.K. Chakraborty, S. Sood, and H.T. Chugani
Alpha-methyl-L-tryptophan PET detects epileptogenic cortex in children with intractable epilepsy
Neurology, March 25, 2003; 60(6): 960 - 968.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
L. A. Gabel and J. J. LoTurco
Layer I Ectopias and Increased Excitability in Murine Neocortex
J Neurophysiol, May 1, 2002; 87(5): 2471 - 2479.
[Abstract] [Full Text] [PDF]

Home page
 Arch NeurolHome page
B. E. Porter, A. Brooks-Kayal, and J. A. Golden
Disorders of Cortical Development and Epilepsy
Arch Neurol, March 1, 2002; 59(3): 361 - 365.
[Abstract] [Full Text] [PDF]

Home page
 NeurologyHome page
M. P. Jacobs, G. D. Fischbach, M. R. Davis, M. A. Dichter, R. Dingledine, D. H. Lowenstein, M. J. Morrell, J. L. Noebels, M. A. Rogawski, S. S. Spencer, et al.
Future directions for epilepsy research
Neurology, November 13, 2001; 57(9): 1536 - 1542.
[Abstract] [Full Text] [PDF]

Home page
 BrainHome page
A. Hammers, M. J. Koepp, M. P. Richardson, C. Labbe, D. J. Brooks, V. J. Cunningham, and J. S. Duncan
Central benzodiazepine receptors in malformations of cortical development: A quantitative study
Brain, August 1, 2001; 124(8): 1555 - 1565.
[Abstract] [Full Text] [PDF]

Home page
 BrainHome page
S. H. Eriksson, M. Thom, J. Heffernan, W. R. Lin, B. N. Harding, M. V. Squier, and S. M. Sisodiya
Persistent reelin-expressing Cajal-Retzius cells in polymicrogyria
Brain, July 1, 2001; 124(7): 1350 - 1361.
[Abstract] [Full Text] [PDF]

Home page
 NeurologyHome page
P. B. Crino, A.-C. Duhaime, G. Baltuch, and R. White
Differential expression of glutamate and GABA-A receptor subunit mRNA in cortical dysplasia
Neurology, April 10, 2001; 56(7): 906 - 913.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
L. A. Gabel and J. J. LoTurco
Electrophysiological and Morphological Characterization of Neurons Within Neocortical Ectopias
J Neurophysiol, February 1, 2001; 85(2): 495 - 505.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
H. J. Wenzel, C. A. Robbins, L.-H. Tsai, and P. A. Schwartzkroin
Abnormal Morphological and Functional Organization of the Hippocampus in a p35 Mutant Model of Cortical Dysplasia Associated with Spontaneous Seizures
J. Neurosci., February 1, 2001; 21(3): 983 - 998.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
W. J. Zhu and S. N. Roper
Reduced Inhibition in an Animal Model of Cortical Dysplasia
J. Neurosci., December 1, 2000; 20(23): 8925 - 8931.
[Abstract] [Full Text] [PDF]

Home page
 BrainHome page
S. M. Sisodiya
Surgery for malformations of cortical development causing epilepsy
Brain, June 1, 2000; 123(6): 1075 - 1091.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
R. A. DeFazio and J. J. Hablitz
Alterations in NMDA Receptors in a Rat Model of Cortical Dysplasia
J Neurophysiol, January 1, 2000; 83(1): 315 - 321.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
P. C. Bush, D. A. Prince, and K. D. Miller
Increased Pyramidal Excitability and NMDA Conductance Can Explain Posttraumatic Epileptogenesis Without Disinhibition: A Model
J Neurophysiol, October 1, 1999; 82(4): 1748 - 1758.
[Abstract] [Full Text] [PDF]

Home page
 Cereb CortexHome page
K. M. Jacobs, M. Mogensen, E. Warren, and D. A. Prince
Experimental Microgyri Disrupt the Barrel Field Pattern in Rat Somatosensory Cortex
Cereb Cortex, October 1, 1999; 9(7): 733 - 744.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online