From the Journal: Lateral septal neurons read out the hippocampal cognitive map as a firing-rate-independent phase code. In this issue of Neuron, Tingley and Buzsáki (pages 1229–1242) describe a neural transformation in which the dynamic weighting of hippocampal theta sequences is converted into firing phases by lateral septal neurons. The cover image is a superimposition of data from a group of lateral septal neurons on concentric circles. Each dot represents an action potential from a single neuron as rats progressed through a circular maze (1 m diameter). The color for each dot represents the simultaneously recorded CA1 theta phase (smoothed across the nearest 15 action potentials; HSV color map [−Π to Π]).
From the Journal: English et al. (pages 505–520) determined that synaptic connections can be identified from the relative timing of two neurons. Moreover, they found that the timing of network activity influences instantaneous connection strength. This image represents these structure-timing relationships, obtained from the raw data which makes up the background. Artwork by Simon Sun.
Drs. Dan English and Sam McKenzie were able to develop a method of determining what neurons were connected to each other in the hippocampus from the timing between neuronal spikes. Neurons will spike when they are activated and this information can be extracted from electrical signals recorded outside of neurons (LFP). This image is an illustration of that relationship. In the background is raw LFP data taken from the hippocampus, from which they determined what neurons were connected, through time (the clock made of neurons).