Related Experiment Video
Updated: Jun 21, 2026
07:33
Optogenetic Entrainment of Hippocampal Theta Oscillations in Behaving Mice
Published on: June 29, 2018
Synaptic noise and physiological coupling generate high-frequency oscillations in a hippocampal computational model
William C Stacey1, Maciej T Lazarewicz, Brian Litt
11Department of Bioengineering, University of Pennsylvania, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19194, USA. William.stacey@uphs.upenn.edu
Journal of Neurophysiology
|August 7, 2009
Summary
Synaptic noise can initiate brain oscillations like gamma frequencies. In epilepsy models, increased noise and altered network connections generate high-frequency oscillations (HFOs), suggesting noise
Area of Science:
- Neuroscience
- Computational Neuroscience
- Computational Biology
Background:
- High-frequency oscillations (HFOs) play roles in normal brain function and are markers of epileptic tissue.
- Mechanisms generating HFOs, particularly in abnormal brain tissue, remain poorly understood.
Purpose of the Study:
- Investigate random synaptic activity (noise) as a potential initiator of HFOs using a hippocampus model.
- Explore parameters for oscillation generation and quantify responses using stochastic resonance (SR) and coherence resonance (CR).
Main Methods:
- Utilized a physiological computer model of the hippocampus.
- Applied principles of stochastic resonance (SR) and coherence resonance (CR) to analyze noise-induced oscillations.
- Systematically varied network parameters, including synaptic noise, coupling, and interneuron presence.
Main Results:
- Noise addition enabled detection of subthreshold signals (SR).
- Basket cell interneurons introduced novel SR effects: enhanced signal detection and noise-driven coherent oscillations.
- Synaptic noise, under normal coupling, generated gamma oscillations (30-100 Hz).
- Pathological parameters (increased gap junctions, reduced inhibition, higher noise) in the model produced ripple-range HFOs (100-200 Hz).
Conclusions:
- Synaptic noise and physiological coupling are sufficient to generate gamma oscillations.
- Pathological changes in noise and coupling, mimicking epilepsy, can produce abnormal HFOs (ripples).
- The model's findings align with experimental data, providing insights into HFO generation in health and disease.
Related Concept Videos
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
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...
01:28Neuronal Communication
Neurons, the fundamental units of the brain and nervous system, communicate through complex electrochemical signals that underpin all cognitive and bodily functions. This communication is primarily facilitated by a process involving the generation and propagation of an action potential along the axon of the neuron. When the internal electrical charge of a neuron surpasses a certain threshold, an action potential is triggered. This rapid change in voltage travels swiftly along the axon to the...
01:09Synaptic Signaling
Neurons communicate at synapses, or junctions, to excite or inhibit the activity of other neurons or target cells, such as muscles. Synapses may be chemical or electrical.
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...
Most synapses are chemical, meaning an electrical impulse or action potential spurs the release of chemical messengers called neurotransmitters. The neuron sending the signal is called the presynaptic neuron, and the neuron receiving the signal is the postsynaptic neuron.
The presynaptic neuron fires an action potential that...