Abstract
We established an in vitro neural recording system combined with computerized connection mediated by model neurons and synapses. With this "dynamic clamp" system, a mutual inhibition circuit between (real) pyramidal cells was constructed. By activating both pyramidal cells simultaneously, we were able to evoke bi-stable activity. Using this system, we ran paradigms that are equivalent to the ones by Levelt (1967, British Journal of Psychology (58) 143-145) to investigate the dynamics of binocular rivalry. The paradigm for Levelt's 4th proposition was modeled by increasing the depolarization currents to both pyramidal cells at the same time. The bi-stability of the pyramidal cells showed increased reversal frequencies in agreement with the Levelt's 4th proposition. The paradigm for the 1st to 3rd propositions was modeled as follows. First, the depolarization currents were adjusted to evoke action potentials at approximately 10Hz. Second, with the mutual connections turned on, the depolarization currents that evoke bi-stable activity with equal dominance between the two neurons were estimated ("standard currents"). Third, the depolarization current to one of the two pyramidal cells was systematically changed. The results were as follows. (1) The increase of the current in one cell caused an increase of the dominance of the cell. (2) The average dominance duration of the dominant cell increased with the increase of the difference of the current from the standard current. (3) The reversal frequency decreased with the increase of the difference of the current from the standard current. The result (1) corresponds to Levelt's 1st proposition but (2) and (3) do not to his 2nd and 3rd propositions, respectively. However, these results (1)~(3) remarkably correspond to the modified propositions by Brascamp and Klink (2015, Vision Research (109) 20-37). This suggests a fundamental role of mutual inhibition circuit in the dynamics of bi-stable perception.
Meeting abstract presented at VSS 2018