Testing the state-dependent model of subsecond time perception against experimental evidence

Abstract

Coordinated movements, speech, and other actions are impossible without precise timing. Computational models of interval timing are expected to provide key insights into the underlying mechanisms of timing, which are currently largely unknown. So far, existing models have only been partially replicating key experimental observations, such as the linear psychophysical law, the linear increase of the standard deviation (the scalar property or Webers law), and the modulation of subjective duration via dopamine. Here, we incorporate the state-dependent model for subsecond timing as proposed by Buonomano (2000) into a strongly data-driven computational network model of PFC We show that this model variant, the state-dependent PFC model, successfully encodes time up to 750 milliseconds and reproduces all key experimental observations mentioned above, including many of its details. Investigating the underlying mechanisms, we find that the representations of different intervals are based on the natural heterogeneity in the parameters of the network, leading to stereotypic responses of subsets of neurons. Furthermore, we propose a theory for the mechanism underlying subsecond timing in this model based on correlation and ablation analyses as well as mathematical analyses explaining the emergence of the scalar property and Vierordt law. The state-dependent PFC model proposed here constitutes the first data-driven model of subsecond timing in the range of hundreds of milliseconds that has been thoroughly tested against a variety of experimental data, providing an ideal starting point for further investigations of subsecond timing. HighlightsO_LIThe state-dependent model of time perception also encodes durations in the subsecond range when embedded into a data-driven network model of the prefrontal cortex. C_LIO_LIThe model reproduces three key experimental findings of time perception: the linear psychophysical law, the scalar property (Webers law) and dopaminergic modulation of subjective durations. C_LIO_LIMany details of experimental observations can be reproduced and explained by the model without specific parameter tuning. C_LIO_LIA new theory for the emergence of Webers law and Vierordts law (overestimation of short durations and underestimation of long durations) is provided. C_LIO_LIThe current variant of the state-dependent model is the first model of time perception to be thoroughly tested against a wide range of experimental evidence and can now be considered to be experimentally validated. C_LI