Synaptic responses of neurons in heterotopic gray matter in an animal model of cortical dysgenesis

Neuronal heterotopia is a malformation of cortical development that is clos ely associated with epilepsy in humans. Despite emerging interest in the st ructure and function of the heterotopic cortex, little is known about the m embrane properties and synaptic connections of these displaced neurons. We used whole-cell patch-clamp and extracellular field potential recordings fr om heterotopic neurons in slices from young adult rats with experimentally induced cortical dysgenesis to determine if local synaptic connections were present in nodular heterotopia. Complex synaptic responses were observed a fter electrical stimulation of adjacent white matter. The results suggest t hat neurons in nodular heterotopic gray matter can form loca I excitatory a nd inhibitory synaptic connections and may participate in epileptiform even ts.