From Phonemes to Discourse: Event-Related Brain Potential (ERP) Componentry and Paradigms for Investigating Normal and Abnormal Language Processing: Marta Kutas, Katherine DeLong, and Michael Kiang
Remarkably, over the past few decades technological advances have made it possible and relatively economical (compared to other neuroimaging methodologies) to investigate normal and abnormal language processing and communication by “reading” patterns of voltage differences between pairs of electrodes on the human scalp. Indeed, electrical brain activity triggered by written, spoken, signed, gestured, or depicted events in the physical world can serve as “potential” windows on the brain’s language-related sensitivities and processing operations. Critically, such electrical potentials can be recorded at all stages of development (from neonates to elderly adults), at various levels of consciousness (from alert or sleeping healthy individuals to comatose or vegetative state patients), and in populations diverse in their abilities to produce motor outputs (as with individuals with apraxia, or who stutter, or Parkinson’s disease patients). These electrical “snapshots” of mental operations do not provide an exhaustive view of all neural processes engaged in, or even essential for, language and thus are not by themselves optimal for localization purposes. They do, however, offer a relatively sensitive index of qualitatively different aspects of neural activity in the neocortex
before, during, and after various linguistic and communicative acts, even in individuals who cannot otherwise effectively relay their messages, desires, or level of understanding.