Figure 6.

Time evolution of model synaptic weights during “normal” mode. The system exhibits fear acquisition, extinction, fear retrieval, and extinction retrieval. Plots show the time evolution of model connection weights during four consecutive epochs. Each plot (A–D) shows the temporal evolution of an array of 20 connection weights, with the y-axis representing the index of the corresponding cell, and the color representing connection strength (Blue is low, red is high). In the first and third epochs, the CS signals co-occur with R⁺, the US. In the second and fourth epochs, the CS signals are presented without R⁺. (Parameters: strength of inhibition f_I = 3.0; input from IL to ITCd E_ILd = 0; input from IL to ITCv E_ILv = 2).