Abstract
Head-direction (HD) signals function as the brain’s internal compass. They are organized as an attractor, and anchor to the environment via visual landmarks. Here we test the hypothesis that HD and landmark signals are associated in the dorsal presubiculum. We find that monosynaptic excitatory connections from anterior thalamic nucleus and from retrosplenial cortex converge on single layer 3 presubicular neurons. Independent dual wavelength photostimulation of these inputs in slices leads to action potential generation preferentially for near-coincident inputs, sending an integrated HD signal to medial entorhinal cortex. Layer 4 neurons, which innervate the lateral mammillary nucleus, form a second step in the association of HD and landmark signals. They are not directly contacted by thalamic and retrosplenial axons. Instead, layer 4 neurons receive a di-synaptic excitation from layer 3, providing a distinct landmark updating of HD signals for transmission to the lateral mammillary nucleus. Thus, a coherent sense of orientation involves projection specific translaminar processing in the presubiculum.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Figure 1 and 3 revised; Section on supralinear subthreshold integration updated with values.
