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Armin Bahl
Smarter than One Might Think: Drosophila as a model for higher cognitive
functions
In the fruit fly Drosophila melanogaster, electrophysiological and imaging techniques as
well as neuronal genetic modifications can be combined at the same time in the behaving
animal. It is that recent fusion of well-established toolsets that makes the fly one of the
most popular model organisms for the study of developmental biology, brain physiology,
neuronal computation and behavior today (Olsen & Wilson, 2010, Seelig et al., 2010). The
Drosophila brain has less than a cubic square millimeter in size and approximately
300.000 nerve cells. Brains of higher organisms like humans have more than 300.000
times more nerve cells and are more than 2 million times larger. These numbers could
lead to the belief that the fly’s behavioral repertoire should be small and of only minor
interest for human neurobiology. But despite their small brains flies do have amazing
abilities, they possess, for example, an elaborated memory and can be trained to associate
colors with objects or odors (Brembs & Heisenberg, 2001). Using visual cues they also
build up spatial memories allowing them to quickly navigate towards a target spot whose
location had be learned before (Foucaud et al., 2010). A well-studied topic in
psychophysics is attention and saliency, which is normally attributed only to higher
organisms but it was shown that the ability to attend to a salient object is also present in
flies (Wolf & Heisenberg, 1980). There is an ongoing debate on whether the freedom of
will might be an illusion and that behaviour instead of being self-initiated is always
deterministic with variability coming from internal or external noise (Heisenberg 2009).
However there are evidences from research in Drosophila that the manoeuvres during
flight might be self-initiated by internal noise-independent mechanisms (Maye et al.,
2007). These examples demonstrate that Drosophila has a long list of exciting and
elaborated abilities and therefore makes it an interesting model organism also for
research in human cognition, physiology and psychology. In combination with the
experimental possibilities in flies it is now possible to tackle the neural basis of these
behaviors which might shed light on the neural representation of learning, attention and
will - might it be free or not.
Arun Singh
Meditation…? Questions for Neuroscientists
Generally, the aim of meditation is modulation of awareness. Any effort free from
distraction of the mind may work as effective meditation. There are two different
meditation categories: concentrative, and non-concentrative. It may be integrated into a
specific spiritual context, but is by itself not specific to religion in general. It includes an
approach to manage stress, anxiety, headache, and daily physical pain complaints. Since
1960, more than 1000 research articles have been published trying to explain the benefits
of meditation. Richard Davidson and Dalai Lama have investigated the effects of
meditation on the brain. For example, one of Davidson’s studies found that long-term
meditators showed high amplitude gamma synchrony during mental practice. All of his
studies imply that intensive meditation results in both functional as well as structural
changes in the brain regions. Investigations performed by Lazar et al have demonstrated
that mediation can increase the density of grey matter and cortical thickness. Meditation
has also been related to alterations of sensory perception, as well as metabolic changes,
e.g. of heart rate, blood pressure, respiration. Given scientific evidence has proved to be
beneficial for mental and physical health, but there is much more left to be yet understood
by neuroscientists.
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