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...

Several spatial coding mechanisms are known to coexist in the hippocampus. However, how are they influenced by various environmental features is still unclear. This study investigated the spatial coding characteristics of hippocampal neurons in mice and rats navigating in different environments. C57BL/6 mice and Long-Evans rats were used in this study. For both mice and rats, most CA1 cells were recorded...

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. Homozygous CaMKIIa-Cre...

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,...

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...

Dopamine is a critical modulator of brain circuits that control voluntary movements. However, its influence on the activity of target neurons in vivo remains limited. In this study, two-photon microscopy was used to monitor the activity of direct and indirect-pathway spiny projection neurons (SPNs) simultaneously in the striatum of behaving mice. The striatum mainly consists of two large populations...

The dorsal root ganglia (DRG) are the first-order neurons in the somatosensory system. However, DRG neuronal activity in awake behaving animals remains unknown. This study developed a method for imaging DRG at cellular and subcellular resolution over weeks in awake mice. They installed an intervertebral fusion mount to reduce spinal movement and implanted a vertebral glass window without interfering...

Wind is a major navigational cue for insects and this study examined how wind direction is decoded by central neurons in the insect brain. They determined that flies combine signals from both antennae to orient to wind during olfactory search behavior. In Drosophila, movements of the antennae are detected by mechanosensory neurons, known as Johnston’s Organ (JO) neurons. The JO neurons project from...

This data was collected to identify the brain regions and circuit organizations that support navigation. In insects, the central complex (CX) is thought to control many aspects of navigation. The CX is a highly organized neuropil, which consists of the protocerebral bridge, the ellipsoid body, the fan-shaped body, and the paired noduli. This study contains electrophysiology, imaging, and behavioral...

Tau is one of the major microtubule-associated proteins in neurons. Its main role is to stabilize microtubules, supporting cytoskeletal organization, and axonal transport. Tau may undergo pathological modifications and become hyperphosphorylated. This causes the protein to accumulate into toxic assemblies that collectively lead to neurodegeneration. In Alzheimer's disease, tau proteins change shape...