Below you will find a number of words that have been identified by the Gathering presenters as words that it would be helpful to know in order to follow along in their presentations. Click the words below to read their definitions.
AED     |     Action Potential     |     Apnea     |     Asystole     |     ASOs     |     Axon     |     Bradycardia
Compound Defects     |     Dendrite     |     Depolarization     |     ECG     |     Electrophysiological Recordings
EMG     |     Functional Analysis     |     Gain-of-Function     |     Heterologous Systems     |     Hyperpnea
Hypopnea     |     In Vitro     |     Loss-of-Function     |     Membrane Potential     |     Mutation     |     Na+ Channel
Neuron     |     Pathogenic Variant     |     Persistent Sodium Current     |     PGES     |     Synapse     |     Tachycardia
Tonic Phase     |
AED: Anti-epileptic drug
Action potential (AP): An action potential, or nerve impulse, is a momentary reversal of the electrical potential across a neuronal plasma membrane that occurs when the neuron has been activated by a stimulus. The AP then stimulates neighboring areas of the plasma membrane of the same neuron, eliciting additional APs further away from the original AP leading to propagation of the AP along the neuron (nerve impulse conduction).
Apnea: “No breathing”, inability to inhale and/or exhale
ASOs (Anti-sense oligonucleotides): ASOs are short fragments of DNA, approximately 20 basepairs long
Asystole:  Absence of heart activity
Axon: A long thin extension of the neuron along which APs (nerve impulses) travel to communicate with other neurons
Bradycardia: Slowed heart rate
Compound defects (in channel function): There is not a single identified abnormality; rather, there are complex abnormalities identified in sodium channels containing a particular epilepsy-associated Nav1.6 variant
Dendrite: Short branches of the neuronal cell body along which impulses received via synapses from other neurons are integrated (summed up) and transmitted to the cell body where a decision is made whether an AP is fired or not.
Depolarization: Reduction of the difference in charge between the inside and outside of a neuron due to sodium ions moving through the plasma membrane.
ECG: ​Electrocardiogram, electrical activity from the heart. 
Electrophysiological recordings: Recordings performed in a laboratory of the electrical properties of sodium channels containing a particular epilepsy-associated Nav1.6 variant relative to a normal control
EMG: Electromyograph, electrical activity from muscle. 
Functional analysis: Testing a specific mutation in a laboratory setting, where tests will reveal if the mutation causes gain- or loss-of-function of the channel
Gain-of-function: When the mutation in the SCN8A gene causes over-activation of the channel
Heterologous systems: Sodium channels containing a particular epilepsy-associated Nav1.6 variant are studied using a model system in the laboratory to attempt to simulate the effects of a particular genetic variant on function of sodium channels
Hyperpnea: Increased breathing
Hypopnea: Decreased breathing
In vitro: Experiments that are conducted in cell lines. Usually this is done in non-neuronal cells (e.g. CHO = Chinese hamster ovary cells) that can be grown quickly in large quantities in the lab. These cells can be manipulated to permanently carry (express) the target of interest (here human NaV1.6 with and without human mutations that cause EE). This is in contrast to “in vivo” which refers to whole animal experiments or “ex vivo”, which refers to experiments on tissues from animals (e.g. brain slices or isolated neurons).
Loss-of-function: When the mutation in the SCN8A gene causes under-activation of the channel
Membrane Potential: The voltage across a membrane that is caused by uneven distribution of ions on the inside vs the outside of a neuron. The inside of a neuron relative to the outside is measured as approximately -70mV.
Mutation: Genetic spelling error on the SCN8A gene causing disease
(Voltage-gated sodium) Na+ channel: A family of ion channels which are complexes that allow for the selective movement of a particular ion (in this case, sodium) across the cell membrane, in response to changes in transmembrane voltage (i.e., the channels open in response to electrical activation of a neuron and lead to a regenerative response that produces an action current or "spike").
Neuron: A specialized cell transmitting nerve impulses (APs). Neurons are electrically excitable cells that communicate with other cells via specialized connections called synapses. Neurons can transmit electrical impulses (APs) by extending axons (see below) to a target region. Nerve impulses / APs can travel along the axon quickly and over long distances without loss of energy due to the specialized properties of the plasma membrane, localization of NaVs and insulating properties of surrounding non-neuronal cells (myelin sheath). Neurons release transmitters from their terminals (synapses at the end of axons) to transfer the signal to the next neuron. Transmitters are small molecules that activate ion channels and receptors on the receiving neuron. Excitatory neurons release transmitters (e.g. glutamate) from synapses that lead to the excitation and ultimately AP firing of the receiving neuron. Inhibitory neurons release transmitters (e.g. GABA) that lead to the reduction of excitation and therefore reduce AP firing in the target neuron. Neurons integrate the excitatory and inhibitory synaptic inputs they receive in their dendrites and this integration (summation) of inputs decides at each moment in time whether the receiving neuron fires an AP or not.
Pictures & more information about neurons: https://www.nichd.nih.gov/health/topics/neuro/conditioninfo/parts
Pathogenic variant: A genetic term used to ascribe causality to a particular finding on a gene panel or exome sequencing test
Persistent sodium current: A small amplitude current that is caused by a small subset of sodium channels that do not inactivate after a stimulus and therefor continue to conduct sodium current for 100s of milliseconds. Persistent sodium current is normally very small but can be significantly increased by mutations that cause seizures (in SCN8A and SCN2A e.g.).
PGES: Postictal Generalized EEG Suppression, when EEG signal is lower than normal immediately after seizure ends.
Synapse: A structure at the end of the axon that allows the neuron to transmit the electrical signal (AP) by releasing a neurotransmitter from the synapse, which will activate receptors and ion channels on the receiving neuron leading to an increase or decrease of AP firing.
Tachycardia: Increased heart rate
Tonic phase:  Period in a seizure when muscle are contracted constantly for an extended time.