From Hearing Sounds to Recognizing Phonemes: Primary Auditory Cortex is A Truly Perceptual Language Area

The aim of this article is to present a systematic review about the anatomy, function, connectivity, and functional activation of the primary auditory cortex (PAC) (Brodmann areas 41/42) when involved in language paradigms. PAC activates with a plethora of diverse basic stimuli including but not limited to tones, chords, natural sounds, consonants, and speech. Nonetheless, the PAC shows specific sensitivity to speech. Damage in the PAC is associated with so-called “pure word-deafness” (“auditory verbal agnosia”). BA41, and to a lesser extent BA42, are involved in early stages of phonological processing (phoneme recognition). Phonological processing may take place in either the right or left side, but customarily the left exerts an inhibitory tone over the right, gaining dominance in function. BA41/42 are primary auditory cortices harboring complex phoneme perception functions with asymmetrical expression, making it possible to include them as core language processing areas (Wernicke’s area).