This project mainly replicates a 1999 paper by Jansen et al. that studies pattern generators in the buccal ganglia of freely behaving snails with a few tweaks of my own. The buccal ganglia is a group of neurons (ganglia) that controls buccal movements – any behavior related to the mouth. In regards to the freely behaving part, it’s very important in neuroscience for the subject to be freely able to move and behave of its own will in order to see the neurons acting in real time.

In theory, the project isn’t that difficult; put an electrode around a neuron in the buccal ganglia and watch the spikes occur at the same time the snail is eating. However, what’s most challenging about this project is the damn setup to get to the point of data collection. Jansen et al. used these 40 mm pond snails called Lymnaea stagnalis which are super cute but incredibly small for a first-time neuroscientist (think the size of your thumbnail).

The paper focused on data collection from three neurons in the buccal ganglia: the posterior jugalis nerve (PJN), the lateral buccal nerve (LBN), and the ventral buccal nerve (VBN) which can be seen in the picture shown. The LBN and VBN actually stem from the same neuronal branch and eventually split into their respective neurons, so for simplicity’s sake, I’m implanting my electrode around the initial branch for both nerves. **This has been updated to put the electrode on one of the esophageal trunks that control the movements of the esophagus.**

In terms of the buccal movement, snails rasp or scrape their toothy tongue called a radula across a surface, like a tank with algae or a piece of spinach, in order to collect food or clean. They rasp when they eat or, interestingly enough, when they lay eggs. The substrate that they lay their eggs on needs to be clean so they rasp it clean. Both of these movements are controlled by the buccal ganglia. The buccal ganglia stimulates the idea of “start rasping,” sends it down one of the neurons, like the LBN or VBN, which then stimulates a muscle that controls the radula to initiate rasping. Jansen et al. found that the electrical activity seen in the spikes changed in frequency and amplitude depending on the behavior at hand. More explicitly, when the snail was eating, the spikes occurred more often with large amplitude versus when the snail was cleaning to lay eggs, the spikes occurred less often and with a lower amplitude (see picture). Although this would be awesome to see for myself, due to time constraints, I will only be observing the electrical activity in accordance with feeding.

Below are the complete instructions for this experiment, if you want to see the whole process (every step and attempt to achieve this project) you can check out the following logs: