The human brain as studied by neuroscientists, or neurobiologists, generally focus on what I would call
implementation details (how specifically does information transport between synaptic channels, i.e. what are the chemical processes)
vague generalities (e.g. about "memory" as a psychological concept and in very vague terms what types of memory there are without studying them mathematically)
There is nothing intrinsically wrong with this.
But I am interested in the brain as a computational system. Of course we don't yet understand the brain very well, but is there a book on the brain that a computer scientist or machine learning professional could read to get a computational/systematic understanding of what we know about the brain? e.g. what is the computational role of various neurotransmitters (without going into chemistry), etc.