A vision of a daydream, or a fragment of reality

The Boston Globe has an interesting piece on daydreaming, touching on the link between daydreaming and creativity and discussing the possibly brain networks that might support our pleasant mental wanderings.

The article discusses some of the recent work on the default brain network and how this might be related to daydreaming:

Every time we slip effortlessly into a daydream, a distinct pattern of brain areas is activated, which is known as the default network. Studies show that this network is most engaged when people are performing tasks that require little conscious attention, such as routine driving on the highway or reading a tedious text. Although such mental trances are often seen as a sign of lethargy – we are staring haplessly into space – the cortex is actually very active during this default state, as numerous brain regions interact. Instead of responding to the outside world, the brain starts to contemplate its internal landscape. This is when new and creative connections are made between seemingly unrelated ideas.

“When you don’t use a muscle, that muscle really isn’t doing much of anything,” says Dr. Marcus Raichle, a neurologist and radiologist at Washington University who was one of the first scientists to locate the default network in the brain. “But when your brain is supposedly doing nothing and daydreaming, it’s really doing a tremendous amount. We call it the ‘resting state,’ but the brain isn’t resting at all.”

It’s worth bearing in mind that the connection between this network and daydreaming is only one theory, and other researchers think of it quite differently.

The ‘default network’ was suggested owing to measurements of how the brain uses energy at rest, and when brain imaging researchers noted that certain parts of the brain (mainly midline areas) were more active when participants didn’t seem to be doing very much but showed reduced activity when we participants were most engaged in attention-demanding tasks.

Neurologist Marcus Raichle has been most vocal in proposing that the network is linked to what we might broadly call daydreaming, mostly notably on the basis of a study that found that default network activity was related to what they called ‘stimulus independent thought’.

They determined this by training people on a memory task until they could do it so easily their minds wandered. They then put people in a scanner, compared brain activation in this condition to brain activation with a similar memory task but where the material was new, so they had to concentrate and weren’t able to think about other stuff.

They found that the practised condition was associated with activity in a default network, and, therefore, they linked it to daydreaming.

The trouble is, is that they only confirmed that participants were doing more off topic thinking, not what they were thinking about.

We might think of daydreaming as having thoughts about being the lead singer of an all-girl skiffle band, fighting a dragon if it happened to burst through the lab door, or screwing the research assistant who took us through the consent form, but it could be that the participants were just focused on the other stuff that was happening around them at the time.

Like the horrendous noise of the fMRI scanner, as some commentators suggested. Or perhaps, they were just being more aware of their wider environment.

And in fact, one theory suggests that the default network is not concerned with daydreaming, but maintains a background level of watchful attention to detect potentially dangerous external events (real dragons, for example), or perhaps processes memories – essentially doing our mental filekeeping.

One big problem with this area, is that it attempts to study a network which is supposedly most active when when not doing deliberate mental tasks, by extrapolating from data that involves the participants doing deliberate mental tasks.

This makes it difficult to tie it specifically to daydreaming, which is a subjective mental state that has a tendency of dancing away whenever we try and catch it.

Link to Globe article ‘Daydream achiever’ (via Frontal Cortex).