Reports tive for nasals (/n m ŋ/). To quantify selectivity at single electrodes, we derived a metric indicating the number of phonemes with cortical responses statistically distinguishable from the response to a particular phoneme (phoneme selectiviNima Mesgarani,1* Connie Cheung,1 Keith Johnson,2 Edward F. ty index (PSI), dimension of 33 English phonemes; PSI=0 is nonselective, Chang1† PSI=32 is extremely selective; Wilcox 1 Department of Neurological Surgery, Department of Physiology, and Center for Integrative Neuroscience, rank-sum test, p
