Protocol for preparing mouse hippocampal slices for ex vivo recordings of the temporoammonic pathway

The temporoammonic pathway (TAP), the direct input from the entorhinal cortex to the hippocampus, is an important model structure for investigating synaptic plasticity. Here, we present a protocol for preparing TAP containing ex vivo slices from mice and conducting extracellular recordings of TAP inputs. We describe the specific slicing plane, an angled horizontal slice preparation, along with anatomical hallmarks for the identification of stimulation and recording electrode placement. We additionally describe techniques to verify TAP electrical stimulation via pharmacological and optogenetic manipulations. For complete details on the use and execution of this protocol, please refer to Keary et al.¹.