| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
|
|---|
| Research Abstract |
We studied the functional and somatotopic properties of 587 thalamic neurons in human patients undergoing stereotaxic surgery for the control of various movement disorders. We designated 429 cells as 'movement-relared neurons', because they responded to passive and/or active joint movement. We labeled 85 cells as 'tapping-related neurons', because they responded to stronger pressure, i.e., (tapping) stimulation, but did not respond to light touch. We called 73 cells 'superficial sensory neurons', since they responded to light touch.
Tapping-related neurons had the characteristics of lemniscal sensory neurons including modality specificity and place specificity, as well as the recovery of excitability and the ability to follow repetitive stimuli. These neurons showed a shell-like distributions 1.0 to 1.5 mm in width, in the anterodorsal area of the Vc (ventrocaudalis) nucleus. Superficial sensory neurons responded to light touch stimulation and also exhibited the characteristics of lemni
… More
scal sensory neurons. These neurons showed a core-like distributions in the Vc nucleus.
Movement-related neurons responded to relatively rapid and strong joint movements and were distributed in the area of the Vim (ventrointermedius) nucleus. By comparing the neuronal receptive fields on the same trajectory from the dorsolateral through the ventromedial portions of the thalamus of individual patients, we identified a topographic representation in the deep structures from the shoulder joint dorsolaterally, to the elbow joint, to the wrist joint and to the finger joint, ventromedially. When the trajectory was targeted more laterally, we identified a topographic representation of the following sequence from the hip joint, to the knee joint, to the ankle joint ventromedially in the deep structures.
These results obtained in the human thalamus are similar to the results of recent studies in the monkey thalamus. We suggest that the functional organization of the human ventrolateral thalamus should be reinterpreted on the basis of these findings and those in the monkey thalamus as described in Jones and Hirai's new parcellation of the thalamus Less
|
