Pascual-Leone A, Torres F
Human Cortical Physiology Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892.
Brain. 1993 Feb;116 ( Pt 1):39-52. doi: 10.1093/brain/116.1.39.
We studied the organization of the somatosensory cortex in proficient Braille readers, recording somatosensory evoked potentials (SEPs) in 10 subjects and using transcranial magnetic stimulation (TMS) in five subjects, and compared the results with those of 15 control subjects. Somatosensory evoked potentials were elicited by a focal electrical stimulus to the tip of the index finger and recorded from a contralateral 4 x 4 grid of scalp electrodes centred around C3' and C4'. Transcranial magnetic stimulation, with an 8-shaped coil centred over the same scalp positions, was delivered simultaneously with, and at different intervals after, the finger stimulus. The results of the right index (reading) finger in Braille readers were compared with those of their left index (non-reading) finger and of the right and left index fingers of the control subjects. The scalp areas from which we recorded N20 and P22 components of the SEP with an amplitude of at least 70% of the maximal amplitude recorded in each trial were significantly larger in SEPs evoked from the reading fingers. Detection of the stimulus applied to the reading finger was blocked by TMS delivered over a larger contralateral scalp area and during a longer time window after the stimulus. These experiments suggest that reading Braille is associated with expansion of the sensorimotor cortical representation of the reading finger.
我们研究了熟练盲文阅读者的体感皮层组织，对10名受试者记录体感诱发电位（SEP），并对5名受试者使用经颅磁刺激（TMS），然后将结果与15名对照受试者的结果进行比较。体感诱发电位由食指指尖的局部电刺激诱发，并从以C3'和C4'为中心的对侧4×4头皮电极网格记录。使用8字形线圈，以相同头皮位置为中心进行经颅磁刺激，在手指刺激的同时以及刺激后的不同时间间隔进行。将盲文阅读者右食指（阅读用）的结果与其左食指（非阅读用）以及对照受试者左右食指的结果进行比较。我们记录到SEP的N20和P22成分且其幅度至少为每次试验中记录到的最大幅度的70%的头皮区域，在阅读手指诱发的SEP中明显更大。施加于阅读手指的刺激检测，在刺激后通过对侧更大头皮区域施加的TMS以及更长的时间窗口被阻断。这些实验表明，阅读盲文与阅读手指的感觉运动皮层表征扩展有关。
