TY - JOUR
T1 - Cell type-specific genetic and optogenetic tools reveal hippocampal CA2 circuits
AU - Kohara, Keigo
AU - Pignatelli, Michele
AU - Rivest, Alexander J.
AU - Jung, Hae Yoon
AU - Kitamura, Takashi
AU - Suh, Junghyup
AU - Frank, Dominic
AU - Kajikawa, Koichiro
AU - Mise, Nathan
AU - Obata, Yuichi
AU - Wickersham, Ian R.
AU - Tonegawa, Susumu
PY - 2014/2
Y1 - 2014/2
N2 - The formation and recall of episodic memory requires precise information processing by the entorhinal-hippocampal network. For several decades, the trisynaptic circuit entorhinal cortex layer II (ECII)→dentate gyrus→CA3→CA1 and the monosynaptic circuit ECIII→CA1 have been considered the primary substrates of the network responsible for learning and memory. Circuits linked to another hippocampal region, CA2, have only recently come to light. Using highly cell type-specific transgenic mouse lines, optogenetics and patch-clamp recordings, we found that dentate gyrus cells, long believed to not project to CA2, send functional monosynaptic inputs to CA2 pyramidal cells through abundant longitudinal projections. CA2 innervated CA1 to complete an alternate trisynaptic circuit, but, unlike CA3, projected preferentially to the deep, rather than to the superficial, sublayer of CA1. Furthermore, contrary to existing knowledge, ECIII did not project to CA2. Our results allow a deeper understanding of the biology of learning and memory.
AB - The formation and recall of episodic memory requires precise information processing by the entorhinal-hippocampal network. For several decades, the trisynaptic circuit entorhinal cortex layer II (ECII)→dentate gyrus→CA3→CA1 and the monosynaptic circuit ECIII→CA1 have been considered the primary substrates of the network responsible for learning and memory. Circuits linked to another hippocampal region, CA2, have only recently come to light. Using highly cell type-specific transgenic mouse lines, optogenetics and patch-clamp recordings, we found that dentate gyrus cells, long believed to not project to CA2, send functional monosynaptic inputs to CA2 pyramidal cells through abundant longitudinal projections. CA2 innervated CA1 to complete an alternate trisynaptic circuit, but, unlike CA3, projected preferentially to the deep, rather than to the superficial, sublayer of CA1. Furthermore, contrary to existing knowledge, ECIII did not project to CA2. Our results allow a deeper understanding of the biology of learning and memory.
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U2 - 10.1038/nn.3614
DO - 10.1038/nn.3614
M3 - Article
C2 - 24336151
AN - SCOPUS:84893715121
SN - 1097-6256
VL - 17
SP - 269
EP - 279
JO - Nature neuroscience
JF - Nature neuroscience
IS - 2
ER -