Download fulltext pdf download fulltext pdf modeling interneuronspecific is interneurons in hippocampus article pdf available in bmc neuroscience 15suppl 1. In the hippocampus gabaergic local circuit inhibitory interneurons represent only 1015% of the total neuronal population. This confirms and considerably extends previous studies of hippocampal interneurons in bipolar disorder. Most parvimmunoreactive neurons in the hippocampus were ngf mrnapositive 82%, which corresponds to 71% of ngfpositive neurons in the hippocampus proper and in the dentate gyrus excluding granule cells. Significance statement longterm potentiation ltp of synaptic transmission within the hippocampus is involved in memory formation and spatial navigation. Here, we demonstrate that ventral ca1 parvalbumin interneurons vca1pvis specifically participated in. Synaptic mechanisms underlying the network statedependent recruitment of vipexpressing interneurons in the ca1 hippocampus. A deficit in parvalbuminexpressing interneurons in the. Therefore, interneurons are the source and the targets of the. Interneurons also entrain pyramidal cells in vitro 7. Aug, 2019 recent studies have identified the hippocampal projection neurons and related pathways that encode and keep social information about familiar conspecifics. Interneurons are the source and the targets of the first.
Vasoactive intestinal polypeptideexpressing interneurons in. Inhibitory interneurons, which make up most of the remaining cell population, frequently show significant placerelated variations in firing rate, but. Longterm synaptic plasticity in hippocampal neurogliaform. Interneurons are specialized with respect to wiring and temporal processing. Expression of ngf and nt3 mrnas in hippocampal interneurons. Hippocampal gabaergic inhibitory interneurons american journal. This overactivity appears to be due to the functional loss of short axon interneurons that control the activity of the primary output neurons of the hippocampus. In this study we examined in detail the connectivity of these neurons by reconstructing their dendritic and. Temporal organization of gabaergic interneurons in the. Dendritic inhibition in the hippocampus supports fear. The large diversity of interneurons 8,9,10 poses the question of whether they have specific roles in shaping distinct network activities in. Hippocampal gabaergic inhibitory interneurons physiological. Interneurons from embryonic development to cellbased therapy.
These constitute the great majority of neurons in the densely packed hippocampal layers. While ltp has been extensively studied in excitatory principal cells, less is known about plasticity mechanisms in inhibitory interneurons, which represent a diverse population of cells. Representations of context incorporate multisensory features of the environment, but must somehow exclude sensory features of the aversive event itself. Interneurons containing calretinin are specialized to control. It sends olfactory information to be further processed in the amygdala, the orbitofrontal cortex ofc and the hippocampus where it plays a role in emotion, memory and learning. Dysfunction of hippocampal interneurons in epilepsy. Animal care and handling were done strictly in accordance with the guidelines set forth by the animal care committee of the university of maryland, baltimore. Somatostatinexpressing interneurons participate only moderately in theta generation but interact with entorhinal cortex inputs to modulate hippocampal theta rhythm. Selective vulnerability of hippocampal interneurons to graded. Herewe use network simulations to investigate how pyramidal cells, connected tothe interneurons and to each other throughampatype andor. Interneurons located in the principal cell and polymorph layers e. In contrast, crh and somatostatin were never coexpressed.
Download fulltext pdf download fulltext pdf modeling interneuron specific is interneurons in hippocampus article pdf available in bmc neuroscience 15suppl 1. Modeling interneuronspecific is interneurons in hippocampus. Somis, another important subtype of inhibitory interneurons in the hippocampus, make up. This shift in spiketiming corresponds to the detected shift in theta oscillations in the dca1 and ica1 lfps. This article is from frontiers in cellular neuroscience, volume 7. This interneuron subtype accounts for 24% of all gabaergic cells in the hippocampal ca1 region. Dendritic inhibition mediated by olm and bistratified. C distinct types of dca1 and ica1 interneurons fire in the same order of cell types but shifted in time. Disruption of inhibitory circuits in this region appears to be linked with the pathology of specific psychiatric disorders, promoting interest in its local circuitry, its role in hippocampal function and its dysfunction in disease. Vasoactive intestinal polypeptideexpressing interneurons. Altered hippocampal interneuron activity precedes ictal onset elife. Interneuron networks in the hippocampus sciencedirect. A characteristic feature of these cellslocated in all areas and layersis the frequent dendrodendritic and axodendritic contacts they form with each other.
Hippocampal pvis are more responsible for higher cognitive functions than are somis 44, 45. Gammaaminobutyric acid gabacontaining interneurons are crucial to both development and function of the brain. Prenatal androgenization induces anxietylike behavior in. Excitatory synaptic inputs onto parvalbumin positive. Institute of experimental medicine, hungarian academy of sciences, budapest, hungary.
Pvalb singlecell rnaseqbased clusters in harris et al. Interneurons belonging to the same type are often coupled by chemical andor electrical synapses. Parvalbumin interneuron in the ventral hippocampus functions. While the number of these 2 subtypes of hippocampal interneurons was significantly reduced, total neuron number and the volume of the pyramidal cell layer were not different from the healthy control group. In contrast, only a subset of calb and calrimmunoreactive interneurons 24% and 23%, respectively displayed hybridization signals for ngf. Further, other dendritic targeting interneurons in the hippocampus also express somatostatin lovettbarron et al. In conclusion, the hippocampus exerts a direct excitatory influence on pfc interneurons and is thus capable of feedforward inhibition of pyramidal cells. Loss, axonal sprouting, and dysfunction of interneurons are regarded as mechanisms involved in epileptogenesis. Buzsaki, interneurons of the hippocampus, hippocampus, 6, no. Hippocampal interneurons in bipolar disorder bipolar and. Shetty1,2,3,4 1medical research and surgery services, veterans affairs medical center, durham, north carolina, united states of america, 2institute for regenerative. Pdf novel markers for olm interneurons in the hippocampus. Abstractthe loss of hippocampal interneurons has been considered as one reason for the onset.
Parvalbumin interneurons of hippocampus tune population. Gamma frequency 3080 hz network oscillations have been observed in the hippocampus during several behavioral paradigms in which they are often modulated by a theta frequency 412 hz oscillation. On the other side of the coin, however, the neural mechanism for animals to determine the stranger in a group achieved little attention. Diverse computations in the neocortex are aided by specialized gabaergic interneurons ins, which selectively target other ins. Among these, a subpopulation of gabaergic interneurons called parvalbumin interneurons pvis or fastspiking interneurons fsis have attracted considerable attention in the last few years 16. Transplanted interneurons develop axonal and dendritic arbors red cell magnified in foreground, synaptically integrate into neural circuits, and modify inhibitory signaling. To examine the contribution of gabaergic interneurons to plaque pathology, we blocked a. Nmda and ampa receptors contribute to the nicotinic. Focusing on ca1 strata pyramidale and radiatum of mouse hippocampus, crh interneurons were found to exhibit a heterogeneous neurochemical phenotype with parvalbumin, cholecystokinin and calretinin coexpression observed to varying degrees. Jan 27, 2019 significance statement longterm potentiation ltp of synaptic transmission within the hippocampus is involved in memory formation and spatial navigation.
We found that during early stages of plaque deposition, interneurons contribute to approximately 30% of the total plaque load in the hippocampus. Here, we found that the ca1 type 3 is cells is3 receive. Simulation of gamma rhythms in networks of interneurons and. Interneurons of the hippocampus have been shown to be crucially involved in rhythms generation, and several subtypes with distinct anatomy and physiology have been. While the number of these two subtypes of hippocampal interneurons was significantly reduced, total neuron number and the volume of the pyramidal cell layer were not different from the healthy control group.
We have successfully used visualized wholecell patchclamp recordings to overcome these problems sah et al. B mean phase angles of individual interneurons during theta oscillations same color code as in a. In addition, when both a pyramidal cell and an interneuron were simultaneously recorded and both responded to stimulation, the interneuron consistently fired before the pyramidal cell. In fact, the majority of inhibitory synapses on pyramidal neurons is found on their dendrites. Experiments and models have shownhow the network frequency depends on excitation of the interneurons,and on the parameters of gaba \rm amediated ipscs betweenthe interneurons conductance and time course. Interneurons that innervate other interneurons acquire gaba a synapses before peridendritic interneurons, but also before perisomatic interneurons that are not yet functional at birth. Influence of the hippocampus on interneurons of the rat. The transition to ictal activity has been characterized in a variety of ways in rodents, including by manual validation henderson et al. Table, we used the mgi mouse go database downloaded 2 april 2018, accessed via. Our studies using a developmental animal model of schizophrenia found hyperactivity in the hippocampus likely drives the disruption in dopamine system function.
Morphological diversity and connectivity of hippocampal interneurons. Sep 30, 2014 in the ca1 region of the hippocampus pyramidal neurons and gabaergic interneurons form local microcircuits. Interneurons from embryonic development to cellbased. Institute of experimental medicine, hungarian academy of sciences, budapest, p. Spinefree calretininimmunoreactive crir interneurons form a subpopulation of gabaergic cells in the rat hippocampus. In contrast, olm interneurons derived from the medial ganglionic eminence partially phase lock to in vitro gamma oscillations and do not express 5ht3a receptors chittajallu et al. Neuregulin 3 promotes excitatory synapse formation on. Interneurons containing calretinin are specialized to. In 28% of the pairs, spike trains elicited from the pyramidal cell caused excitatory postsynaptic potentials epsps in the interneurons. The results of this study indicate that vca1somis do not appear to engage in social memory processes.
In the hippocampus, a highly specialized population of vasoactive intestinal peptideexpressing interneuronspecific is inhibitory cells coordinates the activity of gabaergic interneurons. The hippocampus forms a neural representation of the context that predicts aversive events. Therefore, interneurons are the source and the targets of the first synapses formed in the developing circuit. Highlights multiple interneuron networks coexist in the hippocampus. Novel markers for olm interneurons in the hippocampus frontiers. The level of bdnf expression in the hippocampus and cerebral cortex was analyzed with the western blot test. In the ca1 region of the hippocampus pyramidal neurons and gabaergic interneurons form local microcircuits. This confirms and considerably extends previous studies of hippocampal interneurons in bipolar disorder 16, 17. Paradoxical network excitation by glutamate release from. On the formation of gammacoherent cell assemblies by. Pdf orienslacunosum moleculare olm cells are a major subclass of hippocampal interneurons involved in controlling synaptic plasticity in shaffer. While disinhibition may play a critical role in hippocampal learning, the synaptic properties and recruitment of is cells remain unknown. The ca2 region of the mammalian hippocampus is a unique region with its own distinctive properties, inputs and pathologies.
In agreement with these findings, analysis of neurochemically distinct cohorts of interneurons revealed cell typespecific vulnerability to head injury. Differential susceptibility of interneurons expressing neuropeptide y or parvalbumin in the aged hippocampus to acute seizure activity ramkumar kuruba1,4, bharathi hattiangady1,2,4, vipan k. Cells were procured using enzymatic digestion and manual. Interneurons of the hippocampus freund 1996 hippocampus. Parvalbumin interneuron in the ventral hippocampus. The role of gabaergic interneurons in the cortex and.
Gabaergic local circuit inhibitory interneurons represent only 1015% of the total neuronal population. Simulation of gamma rhythms in networks of interneurons. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Frontiers dendritic inhibition mediated by olm and. Different feedback circuits generate oscillations or resonate with oscillations in other structures. Classes and continua of hippocampal ca1 inhibitory.
Ventral hippocampus, interneurons, and schizophrenia. Hyperdiversity of crh interneurons in mouse hippocampus. Ca1 interneurons are a diverse group consisting of many subtypes, some of which provide compartmentspecific inhibition specifically onto pyramidal neuron dendrites. Differential susceptibility of interneurons expressing. Selective vulnerability of hippocampal interneurons to. Novel markers for olm interneurons in the hippocampus. Hippocampal interneurons express a novel form of synaptic plasticity. Synaptic properties and network statedependent recruitment. We found that during early stages of plaque deposition, interneurons contribute to approximately 30% of. Fear memories guide adaptive behavior in contexts associated with aversive events.
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