Brain Structure and Function

, Volume 217, Issue 1, pp 5–17 | Cite as

Synaptology of ventral CA1 and subiculum projections to the basomedial nucleus of the amygdala in the mouse: relation to GABAergic interneurons

  • M. Müller
  • H. Faber-Zuschratter
  • Y. Yanagawa
  • O. Stork
  • H. Schwegler
  • Rüdiger LinkeEmail author
Original Article


GABAergic neurons of the amygdala are thought to play a critical role in establishing networks for feedback and feedforward inhibition and in mediating rhythmic network activity patterns relevant for emotional behavior, determination of stimulus salience, and memory strength under stressful experiences. These functions are typically fulfilled in interplay of amygdala and hippocampus. Therefore, we explored the putative connectivity of GABAergic neurons with the hippocampo-amygdalar projection with the anterograde tracers Phaseolus vulgaris leucoagglutinin (Phal) and Miniruby injected to GAD67-GFP knock-in mice in which GABAergic neurons are labeled by the expression of the gene for green fluorescent protein (GFP) inserted to the GAD1 gene locus (Tamamaki et al. J Comp Neurol 467:60–79, 2003). We found that, while hippocampal axons target all nuclei of the amygdala, the densest fiber plexus was found in the posterior basomedial nucleus. Electron microscopy revealed that the vast majority of contacts in this nucleus were formed by thin fibers making small asymmetrical contacts, predominantly on GFP-negative profiles. However, several asymmetrical contacts could also be seen on GFP-positive profiles. A surprising result was the occasional occurrence of anterogradely labeled symmetrical synapses indicating a GABAergic contribution to the projection from the hippocampus to the amygdala. While hippocampal input to the amygdala appears to be largely excitatory and targets non-GABAergic neurons, our data provide evidence for a direct involvement of GABAergic neurons in the interplay of these regions, either as target in the amygdala or as projection neurons from the hippocampus. These particular “interface neurons” may be of relevance for the information processing in the amygdalo-hippocampal system involved in emotional behavior and memory formation.


Amygdala Hippocampus GABA GAD GFP Synapse Electron microscopy 



We thank S. Röhl for excellent technical support. Supported by SFB 779-B5 (M.M., H.F.-Z., O.S.,H.S., R.L.) and Grant-in-Aids for Scientific Research from the MEXT, Japan and Takeda Science Foundation (Y.Y.).

Conflict of interest

The authors declare that they have no conflict of interest


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • M. Müller
    • 1
  • H. Faber-Zuschratter
    • 1
  • Y. Yanagawa
    • 2
    • 3
  • O. Stork
    • 4
  • H. Schwegler
    • 1
  • Rüdiger Linke
    • 1
    Email author
  1. 1.Institute of AnatomyOtto-von-Guericke UniversityMagdeburgGermany
  2. 2.Department of Genetic and Behavioral NeuroscienceGumma UniversityMaebashiJapan
  3. 3.Japan Science and Technology AgencyCRESTTokyoJapan
  4. 4.Department of Genetics and Molecular Neurobiology, Institute of BiologyOtto-von-Guericke UniversityMagdeburgGermany

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