An entorhinal-like region in food-caching birds

The mammalian entorhinal cortex routes inputs from diverse sources into the hippocampus. This information is mixed and expressed in the activity of many specialized entorhinal cell types, which are considered indispensable for hippocampal function. However, functionally similar hippocampi exist even in non-mammals that lack an obvious entorhinal cortex, or generally any layered cortex. To address this dilemma, we mapped extrinsic hippocampal connections in chickadees, whose hippocampi are used for remembering numerous food caches. We found a well-delineated structure in these birds that is topologically similar to the entorhinal cortex and interfaces between the hippocampus and other pallial regions. Recordings of this structure revealed entorhinal-like activity, including border and multi-field grid-like cells. These cells were localized to the subregion predicted by anatomical mapping to match the dorsomedial entorhinal cortex. Our findings uncover an anatomical and physiological equi..., , , # An entorhinal-like region in food-caching birds

[https://doi.org/10.5061/dryad.w9ghx3fv1](https://doi.org/10.5061/dryad.w9ghx3fv1)

## Description of the data and file structure

anatomy.mat: a 1x15 data containing all anatomical data. Data for each bird is found in a separate row of the structure. This structure has 2 fields

* bird: the birdID for the animal
* data: a nx8 table. n is the number of detected retrogradely labelled cells in the pallium. For each cell, the following information is stored:
* ROI: the region of interest where the cell was located. This could be 'DL/CDL','HD','NFL','NIL\_M' or 'NIL\_L'.
* Long: the long axis coordinate of the injection. Is either -1, 1, 3, or 5 (see Supplemental table 1)
* Transverse: the transverse coordinate of the injection. Is either 'Hp' or 'DL'
* Hemisphere: the hemisphere of the injection. Is either 'R' or 'L' for right or left hemisphere respectively.
* AP: The AP coordinate of the cell relative to lambda in mm....