The Effect of the K a current on inducement of seizures Stephanie Costa Academy of Notre Dame

Problem Does the substitution of a K a current, instead of a K+ current, in R15 pacemaker network increase seizures in the brain?

Background Information A seizure is the result of brain cells giving off more electrical energy than can be handled by the brain. Abnormal electrical impulses signal a seizure, among other brain related issues. Abnormal electrical impulses can be seen in the data because the neurons do not follow the pattern of the R15 pacemaker neuron. Information travels through the brain by nerve impulses, chemical and electrical signals. The information goes through one neuron, across the synapse and then to the next neuron. Synapses are where two neurons meet, through this junction, cells communicate with each other. The R15 pacemaker is the neuron that sets the rate for all of the other neurons in that network.

Hypothesis The K a current will have an increased probability of seizure occurrences than the regular K+ neuron structure, which will not present any seizures.

Materials Computer SNNAP (Simulator for Neural Networks and Action Potentials) computer system

Procedure Build two neural networks, beginning with R 15 pacemaker neuron. One network will have a regular Hh (K channel) current and the other will have a K a current. Each network will run over a course of 120 seconds. The conductance will be reduced from 2.0 S to 1.0 S at intervals of.1 S The output will be collected from each graph

K channelK a channel

Variables Independent variable: The network that contains the K a current Dependent variable: The output of the K a current Controls: the Hodkin-Huxley model of the neuron Constants: the SNNAP program and the unaltered portions of the neuron/network

Hh model graphs

Hh 2.0

Hh 1.5Hh 1.4

Hh 1.3Hh 1.2

Hh 1.1Hh 1.0

K a model graphs

K a 2.0

K a 1.5K a 1.4

K a 1.3K a 1.2

K a 1.1K a 1.0

Conclusion The hypothesis was rejected. The K a current had a decreased probability of seizures and actually inhibited seizures until a conductance of 1.6 S. A source of error could be the number of K a or K+ channels in the network. Further research could include the results of extremes in the conductance level and the results of different neurons’ conductance when altered.

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