Relation between Spontaneous and Stimulus-Induced Activity: Interaction Model of Brain

The brain and especially its spontaneous activity have been the subject of intense study in both neuroscience and philosophy (as for instance by Klein 2014). However, what exactly counts as spontaneous activity as well as its relationship with stimulus-induced or task-evoked activity remain matters of debate. I here focus on the second aspect, the relationship between spontaneous and stimulus-induced activity. I suggest two different models of their relationship, parallelism and interactionism. I weigh the empirical evidence for and against both models and tentatively suggest that it speaks in favour of interactionism wherein spontaneous and stimulus-induced activity are taken to be mutually dependent on each other and interact in a non-additive way. In addition to empirical evidence, I also discuss the non-additive interaction within the context of philosophy of science by referring to Giere’s distinction between model and fundamental principle. I suggest a particular coding strategy by the brain, e.g., difference-based coding, to underlie and make possible the interaction model – difference-based coding may therefore be regarded a fundamental principle. This complements the empirical findings I present by extrapolating some of the theoretical implications of the interactionist view.