Related Experiment Video
Updated: Jun 18, 2026
13:14
Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue
Published on: October 26, 2014
A nonsynaptic mechanism underlying interictal discharges in human epileptic neocortex
Anita K Roopun1, Jennifer D Simonotto, Michelle L Pierce
1Institute of Neuroscience, The Medical School, Framlington Place, Newcastle University, Newcastle-upon-Tyne NE2 4HH, UK.
Summary
Very fast oscillations (VFOs) in epilepsy may originate from pyramidal cell networks, not interneurons. Reduced gap junction conductance abolished these brain oscillations, suggesting a nonsynaptic origin in human neocortical tissue.
Area of Science:
- Neuroscience
- Epilepsy Research
- Computational Neuroscience
Background:
- Very fast oscillations (VFOs, >80 Hz) are implicated in normal brain function and epilepsy.
- Potential sources include interneuron firing or coupled pyramidal cell axon networks.
Purpose of the Study:
- Investigate the origin of VFOs in human epileptic neocortical tissue.
- Determine the roles of interneurons and pyramidal cell networks in VFO generation during epileptic events.
Main Methods:
- Analysis of spontaneously occurring interictal discharges in human neocortical tissue in vitro.
- Measurement of VFOs in field potentials and synaptic inputs to interneurons.
- Perturbation of synaptic inhibition and gap junction conductance.
Main Results:
- VFOs were observed with interictal discharges, phase-delayed in excitatory inputs to interneurons.
- Low recruitment of pyramidal cell and interneuron spiking; no correlation with VFO power.
- Reduced synaptic inhibition did not affect VFOs.
- VFOs were abolished by reduced gap junction conductance.
Conclusions:
- Interneurons do not appear to play a causal role in VFO generation in this context.
- Findings favor a nonsynaptic, pyramidal cell network origin for VFOs in epileptic human neocortex.
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.
01:28Neuronal 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...
01:25Overview of Synapses
A synapse is a specialized structure where two neurons connect, allowing them to pass an electrical or chemical signal to another neuron. It is the point of communication between neurons. The term "synapse" is derived from the Greek word "synapsis," which means "conjunction." The entire process of neural communication revolves around the synapse. When activated, a neuron releases chemicals known as neurotransmitters into the synapse. These neurotransmitters cross the synapse and bind to...
01:28Electrical Synapses
Electrical synapses found in all nervous systems play important and unique roles. In these synapses, the presynaptic and postsynaptic membranes are very close together (3.5 nm) and are actually physically connected by channel proteins forming gap junctions.
Gap junctions allow the current to pass directly from one cell to the next. In contrast, in the chemical synapse, the neurotransmitters carry the information through the synaptic cleft from one neuron to the next. They consist of two...
Gap junctions allow the current to pass directly from one cell to the next. In contrast, in the chemical synapse, the neurotransmitters carry the information through the synaptic cleft from one neuron to the next. They consist of two...
01:24Epilepsy and Seizures: Overview
Epilepsy is a chronic neurological disease marked by recurrent, unpredictable seizures. These seizures are caused by abnormal electrical discharges in the brain, leading to behavior, sensation, or consciousness alterations. They can also cause transient impairment of awareness, interfering with daily activities.
Various factors can trigger epilepsy, including genetic factors, brain damage, metabolic causes, and unknown etiology. Diagnosis of epilepsy involves electroencephalography (EEG), which...
Various factors can trigger epilepsy, including genetic factors, brain damage, metabolic causes, and unknown etiology. Diagnosis of epilepsy involves electroencephalography (EEG), which...
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...