Role of the Right Temporal Neocortex in Retention of Pitch in Auditory Short-Term Memory

In order to investigate the neural mechanisms underlying short-term memory for auditory information, 71 patients who had undergone focal excision from the left or right temporal or right frontal or fronto-temporal area for the relief of intractable epilepsy were tested, together with 18 normal control subjects, on a task requiring short-term retention of tonal pitch. In the control condition, a target tone was presented, followed 1650 ms later by a comparison tone, and subjects determined whether the two had the same pitch or not. In the interference condition a series of interpolated tones was presented between target and comparison tone. Results indicated that there was no significant impairment in any patient group on the control task. In the interference task there was a significant deficit in retention of tonal information in the patients with right temporal-lobe damage, as well as in those with lesions in the right frontal lobe, and in the right frontal and temporal area. Patients with left temporal-lobe excisions did not demonstrate a significant deficit. These findings are in agreement with research on non-human primates suggesting that structures in the superior temporal gyrus are important in retaining auditory information over short time spans, and further indicate that the human right temporal area is specialized for this function.