Proton magnetic resonance spectroscopic imaging was used to study 23 patients (mean age 28 years (range, 9 to 47)) with cortical developmental malformations and refractory epilepsy examined at the Montreal Neurological Institute, Canada. Lesions included cortical dysplasia (5), heterotopia (12), polymicrogyria (4), and tuberous sclerosis (2). Most focal cortical dysplasias and one half the heterotopias had N-acetylaspartate/creatine (NAA/Cr) signal intensities more than 2 SD below the normal means. The maximal NAA/Cr decrease indicating metabolic dysfunction was localized in the MRI identified malformation and spread to surrounding normal appearing tissue. 
COMMENT. Proton MR spectroscopic imaging (MRSI) will detect neuronal metabolic dysfunction in areas of focal cortical dysplasia defined by MRI and may also demonstrate involvement of surrounding tissue. Different types of cortical developmental malformation, resulting from insults at various stages of cell differentiation and migration, show different degrees of metabolic dysfunction. Imaging techniques that define the structure and metabolism (PET, MRSI) or function (fMRI, EEG) of cortical lesions are important in future investigation of epileptic foci and in studies of the neuroanatomical basis of learning disabilities (See PPN III, 1997;pp 212, 269-276).
Role of transcription factors in the development of the cerebral cortex is reviewed from the Child Study Center, Yale University School of Medicine, New Haven, CT . Regulatory proteins that recognize and bind with DNA stretches within a promoter region are called transcription factors. These factors are themselves regulated by neurotransmitter signals, initiating the transcription of specific target genes. Mutations within these regulatory proteins can affect a number of organ systems, leading to multiple developmental abnormalities.