Input integration around the dendritic branches in hippocampal dentate granule cells

Kamijo, Tadanobu Chuyo; Hayakawa, Hirofumi; Fukushima, Yusuke; Kubota, Yoshihiro; Isomura, Yoshikazu; Tsukada, Masaru; Aihara, Takeshi

doi:10.1007/s11571-014-9280-6

Cited by 10 publications

(9 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…a single spike). Some have used more complex sequences of spatially distributed synaptic inputs [24–26], but the resulting input patterns were still spikes regularly spaced in time. Yet, neuronal spike trains recorded in vivo are not so regular but instead approximately follow a Poisson distribution [27] or a more bursty distribution [28, 29], and what neurons integrate is thus a barrage of irregular synaptic inputs [30, 31].…”

Section: Introductionmentioning

confidence: 99%

Temporal pattern separation in hippocampal neurons through multiplexed neural codes

2019

View full text Add to dashboard Cite

Pattern separation is a central concept in current theories of episodic memory: this computation is thought to support our ability to avoid confusion between similar memories by transforming similar cortical input patterns of neural activity into dissimilar output patterns before their long-term storage in the hippocampus. Because there are many ways one can define patterns of neuronal activity and the similarity between them, pattern separation could in theory be achieved through multiple coding strategies. Using our recently developed assay that evaluates pattern separation in isolated tissue by controlling and recording the input and output spike trains of single hippocampal neurons, we explored neural codes through which pattern separation is performed by systematic testing of different similarity metrics and various time resolutions. We discovered that granule cells, the projection neurons of the dentate gyrus, can exhibit both pattern separation and its opposite computation, pattern convergence, depending on the neural code considered and the statistical structure of the input patterns. Pattern separation is favored when inputs are highly similar, and is achieved through spike time reorganization at short time scales (< 100 ms) as well as through variations in firing rate and burstiness at longer time scales. These multiplexed forms of pattern separation are network phenomena, notably controlled by GABAergic inhibition, that involve many celltypes with input-output transformations that participate in pattern separation to different extents and with complementary neural codes: a rate code for dentate fast-spiking interneurons, a burstiness code for hilar mossy cells and a synchrony code at long time scales for CA3 pyramidal cells. Therefore, the isolated hippocampal circuit itself is capable of performing temporal pattern separation using multiplexed coding strategies that might be essential to optimally disambiguate multimodal mnemonic representations.

show abstract

Section: Introductionmentioning

confidence: 99%

Temporal pattern separation in hippocampal neurons through multiplexed neural codes

2019

View full text Add to dashboard Cite

show abstract

“…Consistent with these findings we did not observe any significant difference in dendritic morphologies (and spine densities) between dentate granule cells of PAR1-deficient and wild type littermate cultures. Although more subtle structural and functional alterations of dentate granule cells may have escaped our detection (e.g., Krueppel et al, 2011 ; Kamijo et al, 2014 ), these results suggest that PAR1 is not a major component of the homeostatic machinery that maintains dendrites under control conditions. PAR1 is not required to mediate the adjustment of dendritic morphologies in denervated brain regions.…”

Section: Discussionmentioning

confidence: 79%

Inhibition of Protease-Activated Receptor 1 Does not Affect Dendritic Homeostasis of Cultured Mouse Dentate Granule Cells

et al. 2016

View full text Add to dashboard Cite

Protease-activated receptors (PARs) are widely expressed in the central nervous system (CNS). While a firm link between PAR1-activation and functional synaptic and intrinsic neuronal properties exists, studies on the role of PAR1 in neural structural plasticity are scarce. The physiological function of PAR1 in the brain remains not well understood. We here sought to determine whether prolonged pharmacologic PAR1-inhibition affects dendritic morphologies of hippocampal neurons. To address this question we employed live-cell microscopy of mouse dentate granule cell dendrites in 3-week old entorhino-hippocampal slice cultures prepared from Thy1-GFP mice. A subset of cultures were treated with the PAR1-inhibitor SCH79797 (1 μM; up to 3 weeks). No major effects of PAR1-inhibition on static and dynamic parameters of dentate granule cell dendrites were detected under control conditions. Granule cells of PAR1-deficient slice cultures showed unaltered dendritic morphologies, dendritic spine densities and excitatory synaptic strength. Furthermore, we report that PAR1-inhibition does not prevent dendritic retraction following partial deafferentation in vitro. Consistent with this finding, no major changes in PAR1-mRNA levels were detected in the denervated dentate gyrus (DG). We conclude that neural PAR1 is not involved in regulating the steady-state dynamics or deafferentation-induced adaptive changes of cultured dentate granule cell dendrites. These results indicate that drugs targeting neural PAR1-signals may not affect the stability and structural integrity of neuronal networks in healthy brain regions.

show abstract

“…In the dendrites of both mature and immature granule cells, sodium action potentials cause calcium transients with high amplitude (Schmidt-Hieber et al, 2007 ; Stocca et al, 2008 ; Hamilton et al, 2010 ; Krueppel et al, 2011 ; Kamijo et al, 2014 ). Yet, a more efficient transient input summation is made possible by immature granule cells, which exhibit longer transients in proximal and distal dendrites.…”

Section: Electrophysiological Features Of Immature and Mature Granulementioning

confidence: 99%

Cell-Biological Requirements for the Generation of Dentate Gyrus Granule Neurons

Hatami

Conrad²,

Naghsh

et al. 2018

Front. Cell. Neurosci.

View full text Add to dashboard Cite

The dentate gyrus (DG) receives highly processed information from the associative cortices functionally integrated in the trisynaptic hippocampal circuit, which contributes to the formation of new episodic memories and the spontaneous exploration of novel environments. Remarkably, the DG is the only brain region currently known to have high rates of neurogenesis in adults (Andersen et al., 1966, 1971). The DG is involved in several neurodegenerative disorders, including clinical dementia, schizophrenia, depression, bipolar disorder and temporal lobe epilepsy. The principal neurons of the DG are the granule cells. DG granule cells generated in culture would be an ideal model to investigate their normal development and the causes of the pathologies in which they are involved and as well as possible therapies. Essential to establish such in vitro models is the precise definition of the most important cell-biological requirements for the differentiation of DG granule cells. This requires a deeper understanding of the precise molecular and functional attributes of the DG granule cells in vivo as well as the DG cells derived in vitro. In this review we outline the neuroanatomical, molecular and cell-biological components of the granule cell differentiation pathway, including some growth- and transcription factors essential for their development. We summarize the functional characteristics of DG granule neurons, including the electrophysiological features of immature and mature granule cells and the axonal pathfinding characteristics of DG neurons. Additionally, we discuss landmark studies on the generation of dorsal telencephalic precursors from pluripotent stem cells (PSCs) as well as DG neuron differentiation in culture. Finally, we provide an outlook and comment critical aspects.

show abstract

Input integration around the dendritic branches in hippocampal dentate granule cells

Cited by 10 publications

References 27 publications

Temporal pattern separation in hippocampal neurons through multiplexed neural codes

Temporal pattern separation in hippocampal neurons through multiplexed neural codes

Inhibition of Protease-Activated Receptor 1 Does not Affect Dendritic Homeostasis of Cultured Mouse Dentate Granule Cells

Cell-Biological Requirements for the Generation of Dentate Gyrus Granule Neurons

Contact Info

Product

Resources

About