Long Term Potentiation: A model of Working Memory in the Hippocampus

This model is a two dimensional depiction of a slice of the Hippocampus and the induction process of Long Term Potentiation . It has been layed out to match the physical likeness of the hippocampal formation, which is a highly specialized area within the limbic cortex. There are several areas that perform functional processes and make up the hippocampal formation. The Entorhinal Cortex (shown in green), provides one of the major sites of neocortical inputs and passes on the information to the rest of the hippocampal structures via a bundle of axons called the Perforant Path . The Perforant path is the shown by the movement of the green circles towards the Dentate Gyrus (Orange Structure). Once the signal is received at the Dentate Gyrus it is passed along to and picked up by the pyramidal cells in the field CA3 (shown in blue). From here the signal is projected onto other pyramidal cells in the Field CA1 (in red) or is sent out to the basal forebrain via the fornix. The CA1 pyramidal cells receives signals from the CA3 cells and structures in the interior of the brain. From here, a bundle of axon connects the CA1 fields from both sides of the bihppocampal formation. These pyramidal cells also provide the main output of the hippocampus and move the signal along a bundle of axons through the subicular complex which leads to cells in the Enotrhinal Cortex.

1)The GO button runs the program.
2)Press SEND SIGNAL to introduce signals into the program. These signals age and die with over time.
3)Potentiation switch toggles on and off a view of the connections being made. As the signals cycle through the hippocampus, they make the connections between the regions discussed above stronger. The lighter the color the more signals that have passed over and the stronger the connection made. Over time, these connections will also fade without use. These connections are not created or faded in real time but act merely as a model
4)Kill Signal. This button will eliminate all present signals.
5)Alcohol slider. This slider is there to show how the presentation of alcohol into a system will disrupt the learning and memory process. Alcohol makes it more difficult to create and maintain these connections as is noted by moving the slider bar further to the right. This is also just an example and is not created in real time.

In order to understand the working memory model, feel free to experiment with the buttons and sliders to get an idea of how the system is integrated.

Program created by Tony Marsh

created with NetLogo

view/download model file: Perforant.nlogo

Neural Communication

Pyramidal Flows

Receptor Action

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