McGill University.
J Cogn Neurosci. 1996 Winter;8(1):29-46. doi: 10.1162/jocn.1996.8.1.29.
Neuropsychological studies have suggested that imagery processes may be mediated by neuronal mechanisms similar to those used in perception. To test this hypothesis, and to explore the neural basis for song imagery, 12 normal subjects were scanned using the water bolus method to measure cerebral blood flow (CBF) during the performance of three tasks. In the control condition subjects saw pairs of words on each trial and judged which word was longer. In the perceptual condition subjects also viewed pairs of words, this time drawn from a familiar song; simultaneously they heard the corresponding song, and their task was to judge the change in pitch of the two cued words within the song. In the imagery condition, subjects performed precisely the same judgment as in the perceptual condition, but with no auditory input. Thus, to perform the imagery task correctly an internal auditory representation must be accessed. Paired-image subtraction of the resulting pattern of CBF, together with matched MRI for anatomical localization, revealed that both perceptual and imagery. tasks produced similar patterns of CBF changes, as compared to the control condition, in keeping with the hypothesis. More specifically, both perceiving and imagining songs are associated with bilateral neuronal activity in the secondary auditory cortices, suggesting that processes within these regions underlie the phenomenological impression of imagined sounds. Other CBF foci elicited in both tasks include areas in the left and right frontal lobes and in the left parietal lobe, as well as the supplementary motor area. This latter region implicates covert vocalization as one component of musical imagery. Direct comparison of imagery and perceptual tasks revealed CBF increases in the inferior frontal polar cortex and right thalamus. We speculate that this network of regions may be specifically associated with retrieval and/or generation of auditory information from memory.
神经心理学研究表明，意象过程可能由与知觉中使用的类似神经元机制介导。为了验证这一假设，并探索歌曲意象的神经基础，12 名正常受试者被使用水团法扫描，以测量在执行三个任务期间的大脑血流 (CBF)。在对照条件下，受试者在每次试验中看到一对单词，并判断哪个单词更长。在知觉条件下，受试者也观看了一对单词，这次是从一首熟悉的歌曲中抽取的；同时，他们听到了相应的歌曲，他们的任务是判断歌曲中两个提示词的音高变化。在意象条件下，受试者执行与知觉条件完全相同的判断，但没有听觉输入。因此，要正确执行意象任务，必须访问内部听觉表示。CBF 结果模式的成对图像减法，以及用于解剖定位的匹配 MRI，显示与对照条件相比，知觉和意象任务都产生了类似的 CBF 变化模式，这与假设一致。更具体地说，感知和想象歌曲都与双侧次级听觉皮层中的神经元活动有关，这表明这些区域内的过程是想象声音的现象印象的基础。两个任务中还激发了其他 CBF 焦点，包括左、右额叶和左顶叶区域以及补充运动区。后一区域暗示了隐蔽发声是音乐意象的一个组成部分。对意象和知觉任务的直接比较显示，下额叶极皮质和右侧丘脑的 CBF 增加。我们推测，这个区域网络可能与从记忆中检索和/或生成听觉信息特别相关。
