overview: During absence seizures, most neurons showed decreased activity. This explains the decline in brain function and disturbance of consciousness during absence epileptic seizures, researchers say.
sauce: Yell
Imagine going in and out of consciousness hundreds of times a day, staying awake and still unconscious.
In children with absence epilepsy, these highly destructive episodes are known as absence seizures. Children experience short staring spells that temporarily cause them to lose consciousness. Absence seizures can be captured by abnormal rhythms in EEG recordings, but their neuronal origins have so far not been identified.
Researchers at Yale University used a genetic model known as the genetically absent epileptic rat of Strasbourg (GAERS) to identify the neural underpinnings of this condition.
Their findings were published on January 10th. Nature Communications.
“First, we used an auditory response task and a voluntarily motivated liquid lick reward task to study behavior during seizures,” said Mark Loughridge and Michele Williams, professors of neuroscience and neuroscience at the Yale School. Lead author Hal Blumenfeld, Ph.D., professor of neurosurgery, said: of medicine.
“We then imaged the rat using functional magnetic resonance imaging. [fMRI] Mapping brain activity during seizures. Finally, we used EEG to record electrical signals from the brain and multi-contact silicon probes to record electrical signals from single neurons. ”
The experiment was led by Cian McCafferty, then a postdoctoral fellow at Yale University and now a lecturer and principal investigator at University College Cork. The team observed that not only did rats’ responses to external stimuli mimic those of children with absence epilepsy, but rats also revealed four different types of neuronal activity during seizures.
“Most neurons showed a sustained decrease in activity during seizures, which explains the decreased brain function and impaired consciousness seen during absence seizures in both rats and children.” Blumenfeld said.
“However, some neurons showed sustained increases during seizures, some showed transient increases only at the onset of seizures, and others showed no changes.”
Defining four types of neuronal activity could allow for more customized treatments for children with absence epilepsy, selectively targeting specific types of neurons with fewer side effects.
Perhaps most importantly, the study’s recording of electrical signals in the brain could help epilepsy professionals prevent seizures and treat patients before they develop, Blumenfeld said.
Blumenfeld and his team have completed the first study of its kind in a rat model, allowing children whose daily activities are hampered by loss of consciousness during absence epileptic seizures to regain a sense of normalcy and I hope to be able to return to activity. they enjoy
About this Consciousness and Epilepsy Research News
author: Beth Connolly
sauce: Yell
contact: Beth Connolly – Yale University
image: image is public domain
See also
Original research: open access.
Hal Blumenfeld et al., “Diminished but variable activity of cortical and thalamic neurons in rodent absence seizures that impair consciousness.” Nature Communications
overview
Decreased but diverse activity of cortical and thalamic neurons in absence seizures in rodents that impair consciousness
Absence seizures are brief episodes of impaired consciousness, behavioral arrest, and unresponsiveness, the neural mechanisms of which are still unknown.
Here, we report that an awake female rat model reproduces the behavioral, electroencephalogram, and cortical functional magnetic resonance imaging properties of human absence seizures. Neuronally, seizures are characterized by an overall reduction but rhythmic firing of neurons in the cortex and thalamus.
Individual cortical and thalamic neurons express one of four distinct patterns of seizure-related activity. One of them causes a temporary initial peak in global firing at the onset of the seizure, another pattern causes a sustained decline in global firing. Forty to 60 seconds before a seizure begins, low-frequency EEG activity, neuronal firing, and behavior begin to decline, while the rhythm of high-frequency EEG and neuronal firing increases.
Our findings suggest that long-lasting changes in brain state precede seizures of unconsciousness, and that during seizures different functional groups of cortical and thalamic neurons exhibit global transient increases in firing followed by sustained have been shown to produce a decrease in spontaneous firing, and an increase in rhythmicity.
