Searching our brains for love, lust, and affection.

We are excited and intrigued when we see pictures of brain activity associated with mental activities. The range of those mental functions captured in maps of brain activity is dazzling. Research ranges from systematic detailed brain imaging studies of specific aspects of attention, perception, memory, sensory processing, to provocative studies exploring what areas of brain light up or are dark when thinking of God, who we like, and the prospects of a trip into space. Most of this research is concerned with furthering our understanding of the neural basis of mind. However some studies have a more practical goal such as identifying our preferences in grocery product or political candidates. The implicit assumption in much of this research is that if humans can experience a function it can be brain imaged. Perhaps another implicit assumption is that if two events trigger different experiences in our ‘mind’ then we should expect maps of brain activity to also differ. Another important assumption is that the maps of brain activity can tell us something about the underlying neural processes that make an experience possible.

Of course themes that focus on high emotions catch our attention the most. The heat of powerful sexual attraction is associated with high activity in areas of the brain that have long been known to be major players in that emotion (such as the hypothalamus).  The cast of brain region characters can be quite detailed. For example Bartels and Zeki at the University of London identified brain foci associated with romantic love to include in the medial insula and the anterior cingulate cortex, and, subcortically, in the caudate nucleus and the putamen. Deactivations of brain regions included the posterior cingulate gyrus and in the amygdala in the prefrontal, parietal and middle temporal cortex. Furthermore maps also provide us with pictures of where the brain is active in relation to the neurochemical basis of emotions (for example brain areas that are rich in the neurochemical transmitter dopamine). Anticipating seeing a loved one triggers activity in frontal and prefrontal lobe regions of the brain that have been well understood to be involved in planning and anticipating the future and regulation of what we find rewarding. Anticipating a fabulous feast after having been on a diet for some time would be associated with heightened activity in some of these same ‘anticipatory’ brain regions but in addition would trigger other areas that are associated with eating behavior.

What are the brain maps telling us and how much of it is like a watching a trailer for a film that we have as yet not seen. First of all pictures of heightened brain activity are averages taken over many second and minutes which is not real time activity of  brain events (which take place in well under a second). In addition even the most sophisticated of the brain imaging machines currently available are averaging activity over a relatively large area of brain (a bit smaller than a centimeter which might appear small but in terms of brain circuitry is enormous). In addition we need to know as much about the role of areas of the brain that are quiet in relation to active areas to appreciate brain maps of mental functions. The pictures of brain activity currently available provides us with brain region candidates associated with some mental function that need to be explored in greater detail if we are to understand the underlying brain mechanisms that are involved in that mental function
We need to be scientifically greedy and demanding of brain imaging studies of mind functions. What we want to really know is a step by step breakdown and depiction of brain activity that is the basis of our experience of an aspect of attention, or with a bigger leap into the dark, how our brain makes the experience of love come alive or the contrasting experience of pain of loss when a lover says goodbye. When ordering a dish from our scientific kitchen we might add that we want our dish served in real time with the neurochemical and neurophysiological details on the same plate. Is that asking for to much from our neuroscience chefs?

(For more details read the article by  A. Bartels; S. Zeki titled, Imaging the neural correlate of romantic love in the 27 Feb. 2009 issue of Science, Vol. 323 pg. 1226)