Fig. 9.

The hippocampus is not required for delay conditioning. (a) To simulate hippocampal lesions before any delay conditioning trials, the scalar β _H in the hippocampus excitation term in Eq. 16 was progressively decreased. There were five training trials with US onset at 550 ms, US duration = 50 ms, US offset at 600 ms, and US level = 1. The results show network activations in response to a CS after training: sensory cortex (S), orbitofrontal cortex (O), hippocampus (H), amygdala (A), hippocampal adaptive timing (R), and the pontine nuclei (P). The CS is represented by vertical solid lines, the US onset during training by a vertical dashed line (in delay conditioning, the CS offset and the US offset coincide). Delay conditioning shows little change in pontine activity in the normal (solid line) versus 50 % (dashed line) and 80 % (dotted line) lesions. (b) Ten learning trials, instead of the five trials in (a), yield better learning, including at the orbitofrontal cortex