title: Inhibitory circuits in human dysplastic tissue.
abstract: OBJECTIVE
  Different types of epilepsies and seizures depend on the nature and location of the primary disturbance and are presumably mediated by different physiopathological mechanisms. We immunocytochemically investigated possible changes in the inhibitory-aminobutyric acid (GABA)ergic system in specimens taken from four patients who underwent surgery for intractable epilepsy and presented two different types of focal cortical dysplasia in the temporal lobe.
  
  
  METHODS
  The patients were selected on the basis of electroclinical, imaging, and routine neuropathological data: two had Taylor focal dysplasia, and two had non-Taylor dysplasia (microdysgenesia). The study was performed using antibodies against parvalbumin (PV), glutamic acid decarboxylase (GAD), and GABA-transporter 1 (GAT1).
  
  
  RESULTS
  In the patients with Taylor dysplasia, laminar disorganization of the cortex was associated with the presence of giant neurons and ballooned cells; there was a reduced number of PV-positive neurons and terminals, the giant neurons were surrounded by clusters of PV- and GAD-positive terminals, and there was an overall reduction in GAT1. Despite the presence of cortical laminar disorganization, no giant or ballooned cells were found in the patients with non-Taylor microdysgenesia; there was a marked decrease in PV and GAD immunoreactive elements, with a patchy distribution of GAD and GAT1 immunoreactivity but no clustering of PV and GAD terminals.
  
  
  CONCLUSIONS
  These results suggest that the two forms of cortical dysplasia are characterized by different and selective morphofunctional alterations in the GABAergic system.
authors.affiliation: Divisione di Neurofisiologia Sperimentale ed Epilettologia, Istituto Nazionale Neurologico C. Besta, Milan, Italy. spreafico@istituto-besta.it
authors.forename: R
authors.initials: R
authors.lastname: Spreafico
authors.forename: L
authors.initials: L
authors.lastname: Tassi
authors.forename: N
authors.initials: N
authors.lastname: Colombo
authors.forename: M
authors.initials: M
authors.lastname: Bramerio
authors.forename: C
authors.initials: C
authors.lastname: Galli
authors.forename: R
authors.initials: R
authors.lastname: Garbelli
authors.forename: A
authors.initials: A
authors.lastname: Ferrario
authors.forename: G
authors.initials: G
authors.lastname: Lo Russo
authors.forename: C
authors.initials: C
authors.lastname: Munari
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000473:pathology* / Q000503:physiopathology; D004833:Epilepsy, Temporal Lobe / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D009434:Neural Pathways / Q000473:pathology*; D009474:Neurons / Q000473:pathology*; D013702:Temporal Lobe / Q000473:pathology* / Q000503:physiopathology; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D005680:gamma-Aminobutyric Acid