This study described a unique set of deep layer neurons in posterior parietal cortex (PPC) whose spiking activity is inversely correlated with all principal cells and interneurons in all brain states, but most commonly during the down state of non-REM (NREM) sleep. They identified down state-active (DSA) neurons as deep layer neocortical neurogliaform cells that express ID2 and Nkx2.1. For this study,...

Chemogenetic technology designer receptors exclusively activated by designer drugs (DREADD) is a widely used experimental method to control neuronal activity with an exogenous receptor. This study virally expressed an excitatory DREADD in all inhibitory interneuron types of the CA1 region of the hippocampus in the rat. For this study, Sprague Dawley rats were used for viral injection and intracranial...

This study described robust oxytocinergic modulation of intrinsic properties and circuit operations in hippocampal area CA2. For this study, male mice were used for all experiments to avoid variation in oxytocin receptor (OXTR) expression throughout the estrous cycle of female mice. C57BL/6 mice were used in wild-type experiments, while homozygous Oxt-IRES-Cre and hemizygote Amigo2-Cre mice were used...

Medial septum (MS) is important for theta generation by either a unitary pacemaker timing signal imposed on the hippocampal system or assisting in organizing target subcircuits within the phase space of theta oscillations. Therefore, this study used temperature manipulation of the MS to test these models. Long Evens rats were water restricted for 22 hours and trained to perform the behavioral task...

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...

Spike sequences are exemplified by memory replays in sharp-wave ripples (SWRs) and high-frequency oscillations resulting from pyramidal cell-interneuron interactions in the hippocampus. However, the microcircuitry mechanism that enables such flexible spike sequencing remains unknown. This study recorded the membrane potentials of multiple hippocampal CA1 pyramidal cells in mice. For this study, whole-cell...

Place cells receive a disparate collection of excitatory and inhibitory currents that provide them with spatially selective discharges and rhythmic activity. This study combined intracellular and extracellular recordings with computational modeling and optogenetic or chemogenetic manipulations to examine the influence of inhibitory and excitatory inputs on CA1 pyramidal cell responses. For this study,...

Polycomb repressive complexes (PRCs) are known for repressing transcription through histone modifications and chromatin compaction. The PRCs consist of two central protein complexes, PRC1 and PRC2, which are important for normal gene regulation and development. This study found that PRC1 is essential for the specification of segmentally restricted spinal motor neuron subtypes, while PRC2 activity is...

Alzheimer’s disease (AD) is characterized by abnormal aggregation of the proteins amyloid-β (Aβ). Recent studies showed that 40-Hz sensory stimulation is a potential treatment in AD. This study examined whether 40-Hz flickering light entrains gamma oscillations and suppresses Aβ in the brains of APP/PS1 and 5xFAD mouse models. For the study, they investigated the effect of 40-Hz light stimulation on...

This study compared the interictal epileptiform discharges (IEDs) of human epilepsy patients from microwire hippocampal recording with those of Alzheimer’s disease (AD) transgenic mice with implanted multilayer hippocampal silicon probes. They investigated the local field potential properties of human IEDs recorded from mesial temporal lobe structures of patients with drug-resistant frontal and temporal...