The Journal of Neuroscience, November 15, 2006, 26(46):11881-11887; doi:10.1523/JNEUROSCI.3389-06.2006
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Cellular/Molecular
GABAergic Excitation in the Basolateral Amygdala
Alan R. Woodruff,1
Hannah Monyer,2 and
Pankaj Sah1
1Queensland Brain Institute and School of Biomedical Sciences, University of Queensland, 4072 Brisbane, Australia, and 2Interdisciplinary Centre for Neurosciences, University of Heidelberg, 69120 Heidelberg, Germany
Correspondence should be addressed to Pankaj Sah, Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia. Email: pankaj.sah{at}uq.edu.au
GABA-containing interneurons are a diverse population of cells whose primary mode of action in the mature nervous system is inhibition of postsynaptic target neurons. Using paired recordings from parvalbumin-positive interneurons in the basolateral amygdala, we show that, in a subpopulation of interneurons, single action potentials in one interneuron evoke in the postsynaptic interneuron a monosynaptic inhibitory synaptic current, followed by a disynaptic excitatory glutamatergic synaptic current. Interneuron-evoked glutamatergic events were blocked by antagonists of either AMPA/kainate or GABAA receptors, and could be seen concurrently in both presynaptic and postsynaptic interneurons. These results show that single action potentials in a GABAergic interneuron can drive glutamatergic principal neurons to threshold, resulting in both feedforward and feedback excitation. In interneuron pairs that both receive glutamatergic inputs after an interneuron spike, electrical coupling and bidirectional GABAergic connections occur with a higher probability relative to other interneuron pairs. We propose that this form of GABAergic excitation provides a means for the reliable and specific recruitment of homogeneous interneuron networks in the basal amygdala.
Key words: axoaxonic; fear; network; learning; excitation; depolarization
Received Aug. 6, 2006;
revised Oct. 8, 2006;
accepted Oct. 9, 2006.
Correspondence should be addressed to Pankaj Sah, Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia. Email: pankaj.sah{at}uq.edu.au
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A. R. Woodruff and P. Sah
Inhibition and Synchronization of Basal Amygdala Principal Neuron Spiking by Parvalbumin-Positive Interneurons
J Neurophysiol,
November 1, 2007;
98(5):
2956 - 2961.
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