The secret life of memory receptors.

The canonical hippocampal NMDA memory receptor also controls the release of the transmitter glutamate and the growth factor BDNF.

Mechanisms of Supralinear Calcium Integration in Dendrites of Hippocampal CA1 Fast-Spiking Cells.

In fast-spiking (FS), parvalbumin-expressing interneurons of the CA1 hippocampus, activation of the GluA2-lacking Ca-permeable AMPA receptors (CP-AMPARs) in basal dendrites is coupled to Ca-induced Ca-release (CICR), and can result in a supralinear summation of postsynaptic Ca-transients (post-CaTs). While this mechanism is important in controlling the direction of long-term plasticity, it is still unknown whether it can operate at all excitatory synapses converging onto FS cells or at a set of synapses receiving a particular input. Using a combination of patch-clamp recordings and two-photon Ca imaging in acute mouse hippocampal slices with computational simulations, here we compared the generation of supralinear post-CaTs between apical and basal dendrites of FS cells.

Connectivity and network state-dependent recruitment of long-range VIP-GABAergic neurons in the mouse hippocampus.

GABAergic interneurons in the hippocampus provide for local and long-distance coordination of neurons in functionally connected areas. Vasoactive intestinal peptide-expressing (VIP+) interneurons occupy a distinct niche in circuitry as many of them specialize in innervating GABAergic cells, thus providing network disinhibition. In the CA1 hippocampus, VIP+ interneuron-selective cells target local interneurons.

Non-linear calcium signalling and synaptic plasticity in interneurons.

Understanding of how intracellular calcium (Ca) signals regulate the efficacy of transmission at excitatory and inhibitory synapses in the central nervous system (CNS) has been a focus of intense investigation. This review discusses recent findings on how Ca signals are integrated in dendrites of inhibitory interneurons to regulate their synapses. In particular, Ca signaling through intracellular Ca release plays an essential role in synaptic signal transduction and experience-dependent plasticity in dendrites of interneurons.

Two-photon Calcium Imaging in Neuronal Dendrites in Brain Slices.

Calcium (Ca) imaging is a powerful tool to investigate the spatiotemporal dynamics of intracellular Ca signals in neuronal dendrites. Ca fluctuations can occur through a variety of membrane and intracellular mechanisms and play a crucial role in the induction of synaptic plasticity and regulation of dendritic excitability. Hence, the ability to record different types of Ca signals in dendritic branches is valuable for groups studying how dendrites integrate information.

Using a Semi-Automated Strategy to Develop Multi-Compartment Models That Predict Biophysical Properties of Interneuron-Specific 3 (IS3) Cells in Hippocampus.

Determining how intrinsic cellular properties govern and modulate neuronal input-output processing is a critical endeavor for understanding microcircuit functions in the brain. However, lack of cellular specifics and nonlinear interactions prevent experiments alone from achieving this. Building and using cellular models is essential in these efforts.

Dendritic inhibition provided by interneuron-specific cells controls the firing rate and timing of the hippocampal feedback inhibitory circuitry.

In cortical networks, different types of inhibitory interneurons control the activity of glutamatergic principal cells and GABAergic interneurons. Principal neurons represent the major postsynaptic target of most interneurons; however, a population of interneurons that is dedicated to the selective innervation of GABAergic cells exists in the CA1 area of the hippocampus. The physiological properties of these cells and their functional relevance for network computations remain unknown.

Dendritic calcium nonlinearities switch the direction of synaptic plasticity in fast-spiking interneurons.

Postsynaptic calcium (Ca2+) nonlinearities allow neuronal coincidence detection and site-specific plasticity. Whether such events exist in dendrites of interneurons and play a role in regulation of synaptic efficacy remains unknown. Here, we used a combination of whole-cell patch-clamp recordings and two-photon Ca2+ imaging to reveal Ca2+ nonlinearities associated with synaptic integration in dendrites of mouse hippocampal CA1 fast-spiking interneurons.

Dendritic Signaling in Inhibitory Interneurons: Local Tuning via Group I Metabotropic Glutamate Receptors.

Communication between neurons is achieved by rapid signal transduction via highly specialized structural elements known as synaptic contacts. In addition, numerous extrasynaptic mechanisms provide a flexible platform for the local regulation of synaptic signals. For example, peri- and extra-synaptic signaling through the group I metabotropic glutamate receptors (mGluRs) can be involved in the highly compartmentalized regulation of dendritic ion conductances, the induction of input-specific synaptic plasticity, and the local release of retrograde messengers.

Functional compartmentalisation and regulation of postsynaptic Ca2+ transients in inhibitory interneurons.

Information processing within neural circuits depends largely on the dynamic interactions between the principal cells and inhibitory interneurons. It is further determined by the efficacy of synaptic transmission between individual circuit elements, which is in turn tightly regulated by changes in network activity to allow for numerous adaptations to occur at a single synapse. Intracellular calcium (Ca2+) is a crucial factor in the regulation of synaptic efficacy in neuronal networks.