Functional anatomy of musical processing in listeners with absolute pitch and relative pitch

Abstract

We used both structural and functional brain imaging techniques to investigate the neural basis of absolute pitch (AP), a specialized skill present in some musicians. By using positron emission tomography, we measured cerebral blood f low during the presentation of musical tones to AP possessors and to control musicians without AP. Listening to musical tones resulted in similar patterns of increased cerebral blood f low in auditory cortical areas in both groups, as expected. The AP group also demonstrated activation of the left posterior dorsolateral frontal cortex, an area thought to be related to learning conditional associations. However, a similar pattern of left dorsolateral frontal activity was also observed in non-AP subjects when they made relative pitch judgments of intervals, such as minor or major. Conversely, activity within the right inferior frontal cortex was observed in control but not in AP subjects during the interval-judgment task, suggesting that AP possessors need not access working memory mechanisms in this task. MRI measures of cortical volume indicated a larger left planum temporale in the AP group, which correlated with performance on an pitch-naming task. Our findings suggest that AP may not be associated with a unique pattern of cerebral activity but rather may depend on the recruitment of a specialized network involved in the retrieval and manipulation of verbal-tonal associations.The existence of special perceptuomotor skills in certain individuals presents many puzzling questions for cognitive neuroscience. One such ability whose cerebral substrate remains essentially unknown is absolute pitch (AP), also known as perfect pitch, a relatively rare ability that refers to a long-term internal representation for the pitch of tones in the musical scale (1, 2). It is typically manifested behaviorally by the ability to identify, by the name of the musical note, the pitch of any sound without reference to another sound or by producing a given musical tone on demand. In contrast, relative pitch (RP), which is well-developed among most trained musicians, refers to the ability to make pitch judgments about the relation between notes, such as within a musical interval.Knowledge about the neural basis for AP is sparse, but three pieces of information are relevant. (i) A case study (3) of an AP possessor who underwent surgical excision within the left temporal lobe for control of epilepsy did not find any deterioration of AP ability; instead, some improvement was noted, which was attributed to a reduction of interference from seizure activity. This finding would suggest that AP does not depend on the integrity of the left anterior temporal lobe but does not clarify which neural structures are crucial for the expression of AP. (ii) Anatomical structural measurements (4) have indicated that there is a more marked left hemispheric asymmetry among AP subjects in the region of the planum temporale (PT), an area of associative auditory cortex often thought to be related to language processes (5)...

Conditional Associative Memory for Musical Stimuli in Nonmusicians: Implications for Absolute Pitch

“…Additionally, we performed a variant of the conjunction analysis introduced by Price and Friston (1997) to determine which areas of activity were common to both the contrast of interest in this experiment and the tone perception condition among AP subjects in the PET experiment of Zatorre et al (1998). Briefly, this consists of performing a logical "AND" operation on all suprathreshold voxels existing in both the t statistic image of the tones Ϫ noise contrast in AP subjects from Zatorre et al (1998) and the t statistic image of the S2 chords Ϫ noise Ϫ S1 chords Ϫ noise contrast in this study.…”

“…Although it seems likely that early and intensive musical training is necessary to develop absolute pitch (AP), these do not seem to be sufficient conditions, and the factors, genetic or otherwise, that interact with this training to dispose the individual to the acquisition of AP are still very much in question (Takeuchi and Hulse, 1993;Baharloo et al, 1998;Zatorre, 2003). A considerable amount of research has delved into various behavioral aspects of AP (Takeuchi and Hulse, 1993;Ward, 1999), but relatively few studies have investigated its neural correlates (Klein et al, 1984;Hantz et al, 1992;Wayman et al, 1992;Zatorre et al, 1998;Keenan et al, 2001). Electrophysiological studies using eventrelated potential techniques Wayman et al, 1992), for instance, have mainly shown a reduced P300 component among AP musicians in auditory oddball paradigms.…”

“…The experiment presented here sought to test the post hoc hypothesis of Zatorre et al (1998) that the posterior DLF cortex is involved in the conditional association between an auditory stimulus and an arbitrary label. We designed a task intended to have limited analogy to AP identification for musically naive subjects and a functional magnetic resonance imaging (fMRI) protocol to detect the predicted involvement of the posterior DLF in the performance of this task.…”

“…We can describe some of the components in the chain of processing needed to accomplish an AP task without understanding how the ability is acquired. In a positron emission tomography (PET) study by Zatorre et al (1998), both AP and non-AP musicians listened passively to single notes and, in a separate condition, identified ascending or descending major or minor thirds. Activation in the left posterior dorsolateral frontal (DLF) cortex for AP possessors when identifying single notes, and nonpossessors when identifying the interval between two notes, was hypothesized to be a reflection of the ability to retrieve an arbitrary conditional association between a stimulus attribute (pitch or interval value) and a verbal label (note or interval name).…”

Perfect pitch reconsidered

“…The authors conclude that AP possessors may compute the size of the musical interval by knowing what the individual notes are, rather than by maintaining pitch in working memory. 14 It has been suggested that some AP possessors do not learn to develop relative pitch in its fullness, because they have learned to rely on AP in their musical activities. 11 Perhaps, then, some AP possessors try to perform interval recognition tasks using the RP strategy, but their comparatively poor sense of RP leads to poorer performance than possessors of RP alone.…”