Using Simple Brains to Understand the Mechanics of Emotion

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Emotion is a tricky beast. We still do not fully understand what triggers a given emotion, in terms of the neurochemical signals in the brain, despite several years of study. This is because of the difficulty of determining whether an electrical pattern is triggering an emotional state, or is caused in response to an emotional state.

Studies on humans cannot really help there, as whilst fMRI can be used to monitor the changing requirements for oxygen in the brain, and non-invasive EEG scans can reveal electrical activity levels, the only way to really know what is going on is to induce new patterns of activity in the target areas and observe the effects. There are some ethical issues with arbitrarily modifying the neural patterns in humans to achieve these results.

Conquering Emotions in Fiction

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This still is taken from the Animatrix short film 'The Second Renaissance (part 2)'. It shows exactly what we require to advance our understanding of the neural processes that govern key areas of the brain, such as emotion, but which we ethically cannot do.

Here the machines are experimenting on still-living humans, connecting electrodes to various areas of the brain, and altering the signal pathways to see what occurs. It is dangerous to work like this of course as you could kill or functionally cripple the human. The machines did not care about this, but we have to. Thus, a different approach to the exact same thing is required.

At the American Association for the Advancement of Science's Annual Meeting in 2010, one neuroscientist made a serious proposal that may well change all that. Howard Hughes Medical Institute investigator David Anderson, admitting that something needs to change, spoke at length about the problems involved in determining emotions through both non-invasive brain reading and neuroprosthetics, arguing for the 'adjust and see' way. Realising that human studies are ethically impossible, argued for flies and other short lifetime creatures to be used in testing such responses, utilising mice and other small mammals once we fully understand the basics, and can work with more complex brains in this manner.

His arguments are hardly surprising, put in context. Anderson's own research has stemmed from exploring the link between neural circuitry and emotional behaviours such as fear and aggression in both mice and fruit flies.

Still, it is a very interesting and promising research direction. Targeted alteration of brain signals, to see how the emotions generated by the creatures change in response. Once we know what we are looking for, the very real possibility of reading a person's emotional state as that emotion forms in the brain becomes a very real possibility. In this eventuality, the emotional state would be detected by a monitoring computer system before the person's expression changes, which would be ideal both to monitor changes in emotional health on real-time, and use that information in perfect sync with other thoughts an actions in an interface system.

It also offers a chance to really study the causes of emotional instabilities and the areas to target to potentially halt them in their tracks.

"We are in the midst of a revolution in the development of new technologies for experimentally manipulating brain circuitry, Anderson said at the meeting. "We need to know which animals are most suitable for studying this complex subject."

The laboratory mouse is amenable to powerful genetics techniques and it has a brain structure that is fundamentally similar to that of humans. But, he says, mouse research is slow, costly, technically difficult, and presents ethical challenges. Invertebrate model organisms, like the fruit fly Drosophila melanogaster, have simpler brains, more powerful genetic tools, and allow for faster, less expensive studies. "But can one study emotional behaviour in a fly?" Anderson asked.