|
The emulation theory of representation postulates that there are multiple internal modeling circuitries in the brain referred to as emulators. These emulators mimic the input-output patterns of many cognitive operations including action, perception, and imagery. Often running in parallel, these emulators provide resultant feedback in the form of mock sensory signals of a motor command with less delay than sensors. These forward models receive efference copies of input motor commands being sent to the body and the resulting output sensory signals. Emulators are continually updating so as to give the most accurate anticipatory signal following motor inputs.〔 == Mechanics and structure == Little is known about the overall structure of emulators. It could operate like a search glossary with a very large associative memory of input-output sequences. Under this system, the emulator receives a motor command input, finds the closest matching input from its database, and then sends the associated output in that sequence. The other model is an articulated emulator. This model requires that for each significant sensor of the human musculoskeletal system there is a group of neurons with a parallel firing frequency within the emulator.〔 These groups of neurons would receive the same input as that being sent to their corresponding part of the musculoskeletal system. For example, when raising one’s hand signals will be sent to neurons responsible for wrist, elbow, and shoulder angles and arm angular inertia. Regardless of this structure both systems will grow and change over time. This is due to constant, fluctuating noise from the environment and the fact that the body changes over time. Growing limbs and muscles result in changes in both required input commands and the resulting output. This requires a degree of plasticity in the emulators. Emulators are thus continually updating, always receiving the resulting output from the musculoskeletal system from an inputted command and comparing it to its own output. It is likely that this is accomplished through Kalman Filter. Complete correction from the difference in outputs, however, is not applied to the emulators. Noise is a constant, fluctuating variable affecting musculoskeletal sensory output. Thus, output differences are almost always greater than they actually should be. Consequently, an internal calculation is made; taking into account the relative reliability of the emulator’s output and if the situational conditions tend to result in very variable or stable sensory outputs, the correction is weighted and applied.〔 The location of these emulators have been found to be largely dependent on the motor system they provide processing and information for. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Emulation theory of representation」の詳細全文を読む スポンサード リンク
|