Department of Biomedical Engineering, Center for Neuroengineering, Duke University, Durham, North Carolina 27710, USA.
J Neurosci. 2012 Oct 10;32(41):14271-5. doi: 10.1523/JNEUROSCI.3115-12.2012.
Artificial sensation via electrical or optical stimulation of brain sensory areas offers a promising treatment for sensory deficits. For a brain-machine-brain interface, such artificial sensation conveys feedback signals from a sensorized prosthetic limb. The ways neural tissue can be stimulated to evoke artificial sensation and the parameter space of such stimulation, however, remain largely unexplored. Here we investigated whether stochastic facilitation (SF) could enhance an artificial tactile sensation produced by intracortical microstimulation (ICMS). Two rhesus monkeys learned to use a virtual hand, which they moved with a joystick, to explore virtual objects on a computer screen. They sought an object associated with a particular artificial texture (AT) signaled by a periodic ICMS pattern delivered to the primary somatosensory cortex (S1) through a pair of implanted electrodes. During each behavioral trial, aperiodic ICMS (i.e., noise) of randomly chosen amplitude was delivered to S1 through another electrode pair implanted 1 mm away from the site of AT delivery. Whereas high-amplitude noise worsened AT detection, moderate noise clearly improved the detection of weak signals, significantly raising the proportion of correct trials. These findings suggest that SF could be used to enhance prosthetic sensation.
通过电或光刺激大脑感觉区域来产生人工感觉为感觉缺失提供了一种很有前途的治疗方法。对于脑机接口，这种人工感觉将来自传感器化假肢的反馈信号传递出去。然而，用于诱发人工感觉的神经组织的刺激方式和这种刺激的参数空间在很大程度上仍未得到探索。在这里，我们研究了随机易化 (SF) 是否可以增强皮质内微刺激 (ICMS) 产生的人工触觉。两只恒河猴学会了使用虚拟手，通过操纵杆移动虚拟手，在计算机屏幕上探索虚拟物体。它们寻找与通过一对植入电极传送到初级体感皮层 (S1) 的周期性 ICMS 模式相关联的特定人工纹理 (AT)。在每次行为试验中，通过另一对植入离 AT 传递部位 1 毫米的电极对传递随机选择幅度的非周期性 ICMS（即噪声）。虽然高幅度噪声会使 AT 检测恶化，但适度噪声显然可以改善弱信号的检测，显著提高正确试验的比例。这些发现表明，SF 可用于增强假体感觉。
