Activation in Primary Auditory Cortex during Silent Lipreading Is Determined by Sex

Abstract

Recent studies investigating whether the primary auditory cortex (PAC) is involved in silent lipreading gave inconsistent results. We used positron emission tomography to identify which areas in the temporal lobe process visible speech, with a focus on the PAC. Subjects were tested on lipreading numbers and only the best lipreaders were included in the study (n = 18; 9 female, 9 male). Each subject was scanned while either watching a movie with a speaker silently articulating numbers (lipreading condition) or watching a static image of the same speaker (baseline condition). Subjects were instructed to repeat internally the number seen or the number ‘1’. Compared to the baseline condition, silent lipreading activated temporal areas in both hemispheres with the largest activation clusters in the left hemisphere. When the whole group was examined, no activation in the PAC was found. But when investigating the two sexes separately, the female group demonstrated activation of the left PAC. There was no significant activation in the right female PAC or in the left and right male PAC. Since both groups had similar performances in lipreading, differential activity in the PAC has no effect on lipreading scores. These results may explain previous inconsistent results where no differentiation for sex was made.

Neural activity underlying tinnitus generation: Results from PET and fMRI

“…Gender differences were found showing differences in the primary auditory cortex between males and females in silent lip reading (Ruytjens et al, 2007a) as well as processing of noise stimuli (Ruytjens et al, 2007b). Subject groups should thus be matched on gender to prevent misinterpretation.…”

Prefrontal Cortex Based Sex Differences in Tinnitus Perception: Same Tinnitus Intensity, Same Tinnitus Distress, Different Mood

“…Furthermore, functional differences in the neural mechanism between sexes in auditory processing have been demonstrated [17]. For example, differences in the primary auditory cortex activation exist between males and females in silent lip reading [18] as well as in processing of noise stimuli [19]. In addition, women demonstrate a greater overall structural connectivity of the underlying organization of their cortical networks than men [20].…”

Neural correlates of human somatosensory integration in tinnitus

“…Examples of this multisensory integration are visual stimuli that modulate activity measured in the auditory cortex (Pekkola et al, 2005) and audiovisual speech or communication signals that modulate activity in the auditory cortex (Calvert et al, 1999;Ruytjens et al, 2006Ruytjens et al, , 2007. In addition to auditory-visual integration, there are studies that specifically assess multisensory integration between the auditory system and the somatosensory system.…”