A recent review article by Friedemann Pulvermuller looks at what is known about the neurobiology of language. He uses the question of what recent progress has been in the where, when, how and why of language processing in the brain. He does a masterful job and yet I am, personally, disappointed. In what way I am disappointed comes later. First comes Pulvermuller’s insights.
Where: We have our old friends Wernicke’s and Broca’s areas and their surroundings, referred to as the left-perisylvian language cortex. They are very heavily connected to one another. But that is not the only where: widespread areas in both hemispheres can be involved depending on the meaning of words. For example the word kick causes activity in areas dealing with the legs.
When: Processing is not serial; phonological, lexical, syntactic, semantic and pragnatic processing are simultaneous. Basic understanding is gained within 250 msec of hearing/seeing even if the utterance is not attended to. Robust activity at about 500 msec depend on a combination of strong (loud) stimulus, attention to it or need for re-analysis.
How: It appears that there is not separation between perception and action but a complex interaction between them involving prediction. Bottom-up sensory activity produces a hypothesis, then a top-down action-like synthesis produces a prediction to be matched with further input.
Why: Here we have a number of important features to explain but very few answers. Basically, the brain needs to do its language work with speed, flexibility and ease of learning.
Now for my disappointment. First, there is a lot here that is similar to non-language processing, especially the predictive testing and monitoring, and this is hardly mentioned. The gulf between studying preception, cognition and action in the language sphere and in other activities is not necessary and hinders progress in both. Secondly, there is my focus of interest, consciousness, which is also hardly mentioned. In the section on timing, it would have been reasonable to notice that event-related-activity that dies out before about 250 msec does not reach consciousness. Those that remain active passed about 300 msec do reach consciousness. This is probably the nature of Pulvermuller’s early and late activity but he does not make the connection. Reaching consciousness allows the use of working memory, which would likely be essential to re-analysis an utterance. Further, consciousness and attention are usually closely linked. I would like to find hints to why language seems more likely to reach consciousness then many other activities and I found none in this article.
Aside from my perhaps unreasonable obsession with consciousness, I hope that many read the article because it brings together the bio and the linguistics in the Bioliguistics Journal.
Friedemann Pulvermuller (2010). Brain-Language Research: Where is the Progress Biolinguistics, 4 (2), 255-288