Ca3 hippocampus

The ca3 hippocampus, in the temporal lobe, ca3 hippocampus, is phylogenetically one of the oldest parts of the brain and forms part of the limbic system. The hippocampus proper is defined by the dentate gyrus and Cornu Ammonis CA. The CA3 region has attracted major attention in recent years for its specific role in memory processes, susceptibility to seizures and neuro-degeneration.

Federal government websites often end in. The site is secure. The hippocampus, in the temporal lobe, is phylogenetically one of the oldest parts of the brain and forms part of the limbic system. The hippocampus proper is defined by the dentate gyrus and Cornu Ammonis CA. The CA3 region has attracted major attention in recent years for its specific role in memory processes, susceptibility to seizures and neuro-degeneration.

Ca3 hippocampus

In the CA3 region of the hippocampus, pyramidal cells excite other pyramidal cells and interneurons. The axons of CA3 pyramidal cells spread throughout most of the region to form an associative network. These connections were first drawn by Cajal and Lorente de No. Their physiological properties were explored to understand epileptiform discharges generated in the region. Synapses between pairs of pyramidal cells involve one or few release sites and are weaker than connections made by mossy fibers on CA3 pyramidal cells. Synapses with interneurons are rather effective, as needed to control unchecked excitation. We examine contributions of recurrent synapses to epileptiform synchrony, to the genesis of sharp waves in the CA3 region and to population oscillations at theta and gamma frequencies. Recurrent connections in CA3, as other associative cortices, have a lower connectivity spread over a larger area than in primary sensory cortices. This sparse, but wide-ranging connectivity serves the functions of an associative network, including acquisition of neuronal representations as activity in groups of CA3 cells and completion involving the recall from partial cues of these ensemble firing patterns. Recurrent connections between CA3 cells in the hippocampus can be seen in early drawings of Golgi stained neurons. So a basis for recurrent excitation existed before synaptic operations were fully accepted.

Neuronal migration and its disorders affecting the CA3 region.

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. On theoretical grounds, the architecture of CA3 circuits seems to be well adapted for the rapid storage and retrieval of associative memories. This is thought to require plastic changes in the strength of specific synaptic contacts.

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. On theoretical grounds, the architecture of CA3 circuits seems to be well adapted for the rapid storage and retrieval of associative memories. This is thought to require plastic changes in the strength of specific synaptic contacts. Dentate gyrus cells provide sparse but powerful synaptic mossy fibre connections to CA3 pyramidal cells, which display a large dynamic range of presynaptic plasticity. Local recurrent connectivity gives rise to the CA3 autoassociative network amenable to spike-timing dependent plasticity, which can be facilitated by heterosynaptic interactions. GABAergic connectivity is subject to prominent structural and molecular plasticity in relation to memory encoding.

Ca3 hippocampus

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. To support cognitive function, the CA3 region of the hippocampus performs computations involving attractor dynamics. Understanding how cellular and ensemble activities of CA3 neurons enable computation is critical for elucidating the neural correlates of cognition. Moreover, the two neuron types have distinct morphological and physiological phenotypes and are differentially modulated by acetylcholine. To understand the contribution of these athorny pyramid neurons to circuit function, we measured cell-type-specific firing patterns during sharp-wave synchronization events in vivo and recapitulated these dynamics with an attractor network model comprising two principal cell types. Our data and simulations reveal a key role for athorny cell bursting in the initiation of sharp waves: transient network attractor states that signify the execution of pattern completion computations vital to cognitive function. This is a preview of subscription content, access via your institution.

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Quantal size is independent of the release probability at hippocampal excitatory synapses. Perez-Rosello, T. Mechanisms of gamma oscillations. E Post-synaptic Ca transients, in response to two pre-synaptic stimuli. An alternate output pathway from the MS to the hippocampus is provided by projections to subiculum and entorhinal cortex, as well as the mammillary bodies. Hippocampal region-specific contributions to memory performance in normal elderly. Kitamura, T. The number of release sites involved in a connection may also be higher in organotypic cultures. Krug, M. As a library, NLM provides access to scientific literature. Intracranially recorded memory-related potentials reveal higher posterior than anterior hippocampal involvement in verbal encoding and retrieval.

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Cite this article Rebola, N. Vyleta, N. Each shaded shape represents a different object. Mechanisms of gamma oscillations in the hippocampus of the behaving rat. Pavlovian pattern learning by nonlinear neural networks. In another high resolution fMRI study Newmark et al. Activity-dependent depression of the spike after-depolarization generates long-lasting intrinsic plasticity in hippocampal CA3 pyramidal neurons. Network state-dependent inhibition of identified hippocampal CA3 axo-axonic cells in vivo. PLoS Comput. Soleng, A. Epac2 mediates cAMP-dependent potentiation of neurotransmission in the hippocampus. One can observe a deficit following dysfunction of either the CA1 or CA3 subregion in a specific set of tasks associated with temporal processing, suggesting an important influence of CA3 output into CA1.