Biomedical Engineering Reference
In-Depth Information
odors with the malaise caused by ingesting amygdalin is mediated by serotonin. The
fi rst hypothesis is under debate as in other experiments with harnessed bees avoid-
ance of bitter substances could not be clearly observed (de Brito sanchez et al.
2005
;
Ayestaran et al.
2010
).
Apart from the learning paradigms on harnessed bees, we have described, until
now, the study of honeybee perception and learning started with visual learning
paradigms on free-fl ying bees. A long experience in such protocols has shown that
free-fl ying honeybees can be conditioned to associate a plethora of sensory stimuli
with sucrose reward, like colors, shapes and patterns, depth, and motion contrast,
among others (von Frisch
1914
; Wehner
1981
; Giurfa and Menzel
1997
; Lehrer
1997
; Giurfa and Lehrer
2001
; see Avarguès-Weber et al.
2011
for review). This
experimental paradigm demonstrated that honeybees learn to categorize visual
stimuli based on perceptual similarity (Giurfa et al.
1996
; Stach et al.
2004
) and also
to classify stimuli based on conceptual rules such as “same,” “different,” “above,”
and “below” (Giurfa et al.
2001
; Avarguès-Weber et al.
2011
), thus showing the
presence of higher-order learning capacities in honeybees.
2.6
Conclusion
Honeybee provides a model system for the study of neural and molecular substrates
of learning and memory and basic cognitive faculties. Olfactory conditioning of
PER in harnessed bees is a particularly helpful protocol to this end as it allows
simultaneous or consecutive monitoring of behavior and of neuronal activity using
extra- and intracellular recording or optical imaging of neural activity (e.g., Hammer
1993
; Faber et al.
1999
; Okada et al.
2007
; Denker et al.
2010
). Local injection or
uncaging of neuromodulatory compounds enables studying the molecular basis
underlying memory formation at local brain region level (Müller
2000
; Devaud
et al.
2007
; Perisse et al.
2009
). Moreover, a great variety of learning paradigms
with different CSs and USs can be applied and may help uncovering whether molec-
ular processes underlying olfactory PER conditioning are general phenomena
shared by other paradigms. The genome sequence of the honeybee
A. mellifera
has
been made available (The Honeybee Genome Sequencing Consortium
2006
), and
application of molecular biological techniques such as RNA interference to investi-
gate honeybee learning and memory has already begun. If new molecular genetics
techniques allowing expression or blocking of the expression of particular genes in
specifi c regions of the honeybee brain appear, this animal model may yet provide
novel breakthroughs in the study of the neural basis of learning, memory, and
cognition.
Here we have aimed at providing a didactic and detailed explanation about basic
procedures to be followed when performing olfactory PER conditioning. We hope,
in this way, that researchers who are unfamiliar (or partially familiar) with this pro-
tocol will become attracted to it by its easiness and robustness and will therefore
help increasing the efforts towards the novel breakthroughs mentioned above.
