We know that the brain uses signals, and that these signals are composed of codes. We know that to interpret the world, certain information processing must take place. We are learning more about the exact nature of this processing, more about how neurons and even other fundamentals of the body code information and contribute to processing (e.g. chemical processes), but they definitely process information. We even know some of the codes.
On the other hand, if the author wants to argue about the nature of what is information, what is processing.. he's going to have a steep hill to climb.
From this we can often find things like:
- frequency of impulses increases as stimulus increases
- different numbers of neurons in a similar area fire simultaneously
Things like that. The wikipedia articles linked by wickedagain contain a good summary. I won't link specific sources, since there are thousands, but here's one for instance:
http://jn.physiology.org/content/85/4/1561
There in fig 6 for example you can see that the frequency of nerve firing increases in the tibial nerve as heat is applied to the paw. (Yes, a lot of information comes from horrible animal studies. It's part of the reason I didn't continue in this domain of work -- although rest assured, this technique is possible with humans, without harm.)
So, do impulses in the perceptual nervous system reflect how brains work, how we think? It's hard to say for sure, but it's clear that information is coded according to certain possibilities related to how neurons work, and this information must be combined and processed somehow to create what we call perceptions. Is it such a stretch to imagine that these perceptions become their own codes, abstract reductions of correlations of perceptual information, that are evaluated, compared, and combined in the much, much more nerve-dense central cortex to produce what we call "thought"?
A further frustration might be with computers themselves. I don't see why an introduction/exposition to computing should be something that needs pardon.
Given the author's background, I'd put money on the idea that this is the result of years of frustration at having his life's work dismissively reduced by casual observers to something like "yeah, it's basically a computer" and thinking they therefore understand all the intricacies of the human brain. I can see how that might grate on a person in his field and trigger a response like this.