Neurologically, how does a thought terminate? What prevents my brain from holding the same thought forever, like a frozen computer?
How do neurons terminate a firing pattern and move onto the next?
I'm not sure if the neuroscientific community has reached a consensus on what a &quot;thought&quot; is, but it seems you're using it here as synonymous with a neuronal firing pattern.
If one models this as an attractor in a dynamical system of a circuit or network of neurons, then I would look into Ichiro Tsuda's concept of &quot;chaotic itinerancy&quot; http://www.scholarpedia.org/article/Chaotic_itinerancy which gives a formalization for how attractors transition to chaos then to [usually new] attractors.
An important intuitive notion is that attractors dissipate when they become unstable.
If a sensory stimulus or a memory or imagination creates a stable pattern of neurons that fire in association with it, then what initiated the firing pattern in the first place seems like it should have something to do with how it destabilizes. There is a causal connection between stimulus and neuronal activity. I believe attention would affect what fires and for how long, and Karl Friston's &quot;free energy principle&quot; seems like a good formalization of how that happens, but I haven't fully studied it myself.
There is a counterintuitive observation where neurons adjacent to those of the receptive fields of a sensory stimulus can keep firing for up to 3 hrs after the stimulus (cf. &quot;Plasticity of Receptive Fields in Early Stages of the Adult Visual System&quot; U.T. Eysel, in &quot;Perceptual Learning&quot;, M. Fahl &amp; T. Poggio, eds), so maybe the neuronal substrate of thoughts last longer than they consciously appear to. My guess is they would only last forever if there was nothing else to think about