This study examined how incorporation of synthetic hippocampal signals is constrained by pre-existing circuit dynamics. The postulated ability for hippocampal circuits to imprint a random, novel pattern was tested in CaMKIIα-Cre::Ai32 mice (N = 5) in which channelrhodopsin2 was expressed in excitatory pyramidal neurons. For the study, μLED silicon probes were implanted in dorsal CA1 to record neural...

The medial septum is critical in theta generation by two possible mechanisms: a unitary ‘pacemaker’ timing signal is imposed on the hippocampal system or it may assist in organizing target subcircuits within the phase space of theta oscillations. Therefore, this study used temperature manipulation of the medial septum to test these models. Long Evans rats were implanted with silicon probes and tungsten...

Hippocampus plays a key role in navigation guided by environmental inputs. However, a critical aspect of navigation is a sequence of planned and coordinated actions. This study investigated the role of action in the neuronal organization of the hippocampus by training rats to jump a gap on a linear track. For this study, Long-Evans rats were used for recording local field potentials and ensembles of...

Hippocampal activity supports internal representation of learned experiences and contexts, which allows individuals to form long-term memories. This study investigated hippocampal maps formed under structured attention with learning rules stabilize and maintain task-selectivity during memory recall. They used longitudinal two-photon imaging of hundreds of hippocampal CA1 pyramidal neurons while mice...

This study investigated the subthreshold dynamics using optogenetic depolarizing pulses in hippocampal neuronal assemblies in freely moving mice to understand how excitatory and inhibitory inputs are integrated by neurons. For the study, they recorded and examined large numbers of CA1 pyramidal neurons simultaneously in freely moving CamKIIα-Cre::Ai32 mice. This dataset contains electrophysiology and...

Previous studies indicated that the fraction of splitter fields is affected by the delay between responses in a spatial alternation task. This study demonstrated that memory and place field features of both pyramidal cells and interneurons in the hippocampus are interchangeable. They trained two groups of mice with and without delays in one or two environments and examined firing characteristics of...