Irmgard Amrein, University of Zurich - Switzerland

Tuesday, 12th September - h. 14:00
Seminars Room, NICO

Structure-function relations of the hippocampal formation

Irmgard Amrein
Institute of Anatomy, University of Zurich (UZH/ETH Zurich, Switzerland)
The mammalian hippocampus plays a pivotal role in spatial navigation, memory and emotionality. Information processing in the hippocampal formation follows a general feed-forward loop, and distinct principal neuron populations along this loop serve defined computational tasks. These neuron populations show species-specific differences in cytoarchitecture, connectivity, and neurochemical and genetic signaling on a qualitative level. Such variations are difficult to interpret and to test for functional significance if only isolated species are investigated. This is because it is not clear if a difference serves species-specific adaptions or if it has arisen in higher-level taxonomic units.

In a broad range of species, we have estimated neuron population sizes to reveal changes in composition and interconnections of these hippocampal neurons within and between species groups. We found clusters of species that correspond to taxonomic units, such as a rodent cluster, defined by a relatively large CA3 neuron population. Deviations become apparent too. Humans for example do not cluster with other primates, as the CA1 neuron population of humans is larger and the hilar cell population is smaller than in marmoset or rhesus monkeys. Ultimately, we aim for testing if observed variations follow linked regularities or if they represent mosaic changes on the phylogenetic scale, and how the observed diversity in cellular compositions can be integrated into computational models of hippocampal function.

Host: Luca Bonfanti