Two different forms of long-term potentiation at CA1-subiculum synapses
Christian Wozny1, Nikolaus Maier, Dietmar Schmitz
1Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany. cwozny@mrc-lmb.cam.ac.uk
The Journal of Physiology
|April 12, 2008
Summary
The subiculum
Area of Science:
- Neuroscience
- Synaptic Plasticity
- Hippocampal Formation
Background:
- The subiculum, part of the hippocampal formation, processes information between the hippocampus and neocortex.
- Subicular pyramidal cells are classified as bursting or regular firing.
- Understanding synaptic plasticity in these cells is crucial for memory and learning.
Purpose of the Study:
- To investigate and compare long-term potentiation (LTP) in regular firing and bursting subicular neurons.
- To elucidate the distinct mechanisms and locations of LTP expression in these two cell types.
Main Methods:
- Induced long-term potentiation (LTP) using prolonged high-frequency stimulation.
- Measured NMDA receptor dependency.
- Assessed postsynaptic calcium levels.
- Utilized paired-pulse facilitation to determine the site of LTP expression.
Main Results:
- Both cell types exhibited NMDA receptor-dependent LTP.
- Regular firing neurons required postsynaptic calcium for LTP, while bursting neurons did not.
- LTP expression was postsynaptic in regular firing neurons and presynaptic in bursting neurons.
Conclusions:
- Regular firing and bursting cells in the subiculum possess distinct physiological roles.
- These functional differences in synaptic plasticity contribute to distinct roles in processing hippocampal output.
- Findings highlight the subiculum's complex role in learning and memory.
Related Concept Videos
01:25Long-term Potentiation
Long-term potentiation, or LTP, is one of the ways by which synaptic plasticity—changes in the strength of chemical synapses—can occur in the brain. LTP is the process of synaptic strengthening that occurs over time between pre and postsynaptic neuronal connections. The synaptic strengthening of LTP works in opposition to the synaptic weakening of long-term depression (LTD) and together are the main mechanisms that underlie learning and memory.
Hebbian LTP
LTP can occur when presynaptic neurons...
Hebbian LTP
LTP can occur when presynaptic neurons...
01:35Long-term Potentiation
Long-term potentiation, or LTP, is one of the ways by which synaptic plasticity—changes in the strength of chemical synapses—can occur in the brain. LTP is the process of synaptic strengthening that occurs over time between pre- and postsynaptic neuronal connections. The synaptic strengthening of LTP works in opposition to the synaptic weakening of long-term depression (LTD) and together are the main mechanisms that underlie learning and memory.
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
01:28Integration of Synaptic Events
Synaptic integration mainly includes the summation of graded potentials. Graded potentials, regardless of their type, cause subtle alterations in membrane voltage, resulting in either depolarization or hyperpolarization. These incremental changes, when combined or summed, can propel the neuron toward its threshold. Consider, for example, a membrane experiencing a +15 mV shift, causing it to depolarize from -70 mV to -55 mV. In this scenario, graded potentials govern the membrane's ability to...
01:48ATP Synthase: Mechanism
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...