You're coming to this discussion with an unjustified assertion that thinking is very narrowly defined and then circularly showing that other kinds of things that neurons can do are not "thinking" because they don't fit the definition.

In the huge space of all possible kinds of cognition, humans have only ever occupied the tiniest sliver. There's modes of thought out there that we can't conceive of.

To ask "what is this mammal thinking" is self-evidently closer to asking "what is that mammal thinking" than it is to "what is that computer thinking".

Those are good questions with unknown answers. Another good question is "what people are thinking?"