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Structural and functional investigations of the avian hippocampal formation


Birds possess a hippocampal area that, in contrast to its mammalian homolog, lacks a layered structure and whose anatomical subdivisions are still highly debated. By using experimental setups equivalent to those used for rodents (e.g. 'dry version of the Morris water maze' and orientation in geometrical enclosure) in combination with neurobiological methods (e.g. single unit recording and histochemical detection of neuronal activity markers) we question how far theories developed for mammalian hippocampus can also be applied to the avian hippocampal formation.

Dry Morris Water Maze                    HF-c-Fost  
'dry version of the Morris water maze'             IEG-expression in the hippocampus             


Visual processing in the avian brain

In humans visual information is transmitted by about 1 million fibers within each optic nerve, which is only 40% of the number of fibers within each optic nerve of domestic chicks.  Indeed, birds are probably the most visually advanced class of vertebrates. However, while the homologies between the visual pathways of birds and mammals are well understood, the functional equivalences between the later visual processing stations in the birds pallium and the mammalian visual cortexes are still unclear. This is particularly relevant for the study
of comparative cognition since precisely those later processing stations carry out more sophisticated computations of the visual information, which are involved also in higher cognitive functions. We study these visual properties in birds by combining behavioral, neuroanatomical and neurophysiological techniques.
Orientation Neurons        Retinotopic Maps
Direction selective neurons and retinotopic maps within the visual wulst in zebra finches

Neuronal mechanism of social interaction in birds

Visually naive domestic chicks (Gallus gallus) preferentially approach animate objects that resemble conspecifics (e.g., face-like or biologically-moving stimuli). In a series of experiments, we investigate specifically which of the configurational and motional informations cause this attraction and also the neuronal basis mediating this behaviour.

Conspecific              Septum    
A living conspecific vs. stuffed chicks                   IEG-expression in septum