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首页> 外文期刊>Journal of Neurophysiology >Neuronal activity in somatosensory cortex of monkeys using a precision grip. II. Responses To object texture and weights.
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Neuronal activity in somatosensory cortex of monkeys using a precision grip. II. Responses To object texture and weights.

机译：使用精密握把在猴子的体感皮质中进行神经元活动。二。对对象纹理和权重的响应。

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Three monkeys were trained to lift and hold a test object within a 12- to 25-mm position window for 1 s. The activity of single neurons was recorded during performance of the task in which both the weight and surface texture of the object were systematically varied. Whenever possible, each cell was tested with three weights (15, 65, and 115 g) and three textures (smooth metal, fine 200 grit sandpaper, and rough 60 grit sandpaper). Of 386 cells recorded in 3 monkeys, 45 cells had cutaneous receptive fields on the index or thumb or part of the thenar eminence and were held long enough to be tested in all 9 combinations of texture and weight. Recordings were made for the entire anterior-posterior extent of the thumb and index finger areas in somatosensory cortex including area 7b. However, the statistical analysis required a selection of only those cells for which nine complete recording conditions were available limiting the sample to cells in areas 2, 5, and 7b. Significant differences in the grip force accompanied 98% of the changes in texture and 78% of the changes in weight. Increasing the object weight also increased the force tangential to the skin surface as measured by the load or lifting force. The peak discharge during lifting was judged to be the most sensitive index of cell activity and was analyzed with a two-way analysis of variance (ANOVA). In addition, peak cell discharge was normalized to allow comparisons among different combinations of texture and weight as well as comparisons among different neurons. Overall, the peak firing frequency of 87% of the cells was significantly modulated by changes in object texture, but changes in object weight affected the peak activity of only 58% of the cells. Almost all (17/18, 94%) of the static cells were influenced by the object texture, and 81% of the dynamic cells that were active only briefly at grip and lift onset were modulated by texture. For some cells, surface texture had a significant effect on neuronal discharge that was independent of the object weight. In contrast, weight-related responses were never simple main effects of the weight alone and appeared instead as significant interactions between texture and weight. Four neurons either increased or decreased activity in a graded fashion with surface structure (roughness) regardless of the object weight (P < 0.05). Ten other neurons showed increases or decreases in response to one or two textures, which might represent either a graded response or a tuning preference for a specific texture. The firing frequency of the majority (31/45) of neurons reflected an interaction of both texture and weight. The cells with texture-related but weight-independent activities were thought to encode surface characteristics that are largely independent of the grip and lifting forces used to manipulate the object. Such constancies could be used to construct internal representations or mental models for planning and controlling object manipulation.
机译：训练了三只猴子，将测试对象举起并保持在12至25毫米的位置窗口内1秒钟。在执行任务期间记录单个神经元的活动，在该任务中，对象的重量和表面纹理都有系统地变化。只要有可能，就用三个砝码（15、65和115 g）和三个纹理（光滑的金属，200粒度的细砂纸和60粒度的粗砂纸）测试每个电池。在3只猴子中记录的386个细胞中，有45个细胞在食指，拇指或鱼际隆起的一部分上具有皮肤感受野，并保持足够长的时间，可以在所有9种质地和重量组合中进行测试。记录了包括7b区在内的躯体感觉皮层中拇指和食指的整个前后区域。但是，统计分析仅需要选择可用于九种完整记录条件的那些单元，从而将样本限制为区域2、5和7b中的单元。握力的显着差异伴随着98％的质地变化和78％的重量变化。物体重量的增加也增加了与皮肤表面相切的力，该力通过负载或举升力来测量。提升过程中的峰值放电被认为是细胞活性的最敏感指标，并通过方差双向分析（ANOVA）进行了分析。另外，将峰值细胞放电标准化以允许在质地和重量的不同组合之间进行比较以及在不同神经元之间进行比较。总体而言，物体纹理的变化显着调节了87％的细胞的峰值发射频率，但是物体重量的变化仅影响了58％的细胞的峰值活性。几乎所有（17/18，94％）的静态单元格都受对象纹理的影响，而81％的仅在抓握和抬起时短暂活动的动态单元格受到纹理的影响。对于某些细胞，表面纹理对神经元放电有重要影响，而与物体重量无关。相反，与体重有关的反应绝不是单纯的体重的简单主要影响，而是作为质地和体重之间的重要相互作用而出现的。不管物体的重量如何，四个神经元以具有表面结构（粗糙度）的渐变方式增加或减少了活动（P <0.05）。其他十个神经元显示出对一种或两种纹理的响应增加或减少，这可能代表对特定纹理的分级响应或调整偏好。多数神经元（31/45）的放电频率反映了质地和重量的相互作用。人们认为具有与纹理相关但与重量无关的活动的单元对表面特征进行编码，这些特征在很大程度上与用于操纵物体的抓地力和提升力无关。这样的一致性可用于构建内部表示或心理模型，以计划和控制对象操纵。

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