In the project instructions, I’ve briefly talked about the BYB SpikeRecorder app that I’ve been using on an iPad to add to my grasshopper vision project the flavor of a low-cost-and-DIY-albeit-of-great-quality tool. Here, I’ll talk about it in a bit more details to give the spotlight to one of the main components of my project.
Firstly, the purpose of the original SpikeRecorder version that BYB has published is to record data directly to your PC (or tablets & smartphones) while you can observe the recording in real time. There’s also the functionality of saving the recording to be played back anytime. And if you’re familiar with the classic model of an action potential (aka spikes!), the SpikeRecorder also allows a threshold view, where you can set your threshold and get a snapshot of your spikes.
This is a classic “spike” event when the electrochemical properties of a neuron is at work. These spikes are essentially changes in voltage due to the chemical and electrical difference inside and outside of a neuron’s membrane. Movements of sodium and potassium across the membrane via channels and the way their charges get distributed — these are the main components of a spike.
Art by Backyard Brains
If you’re interested in checking out this app and perhaps get some spikes, the app is available for android and ios. And of course, the code is on github for the open source spirit!
One of my mentors, Stanislav Mircic, is the computer science god of BYB. He graciously added the “Grasshopper experiment” functionality to the app. The app now can provide both the visual stimuli (simulated balls thrown at grasshopper’s eye) and recording/analysis of the DCMD neuron activity.
Sorting a bunch of spikes at once:
Zooming into one DCMD spike!
By Dieu My Nguyen
After a long and difficult time discovering the buccal ganglia, I recommend using a microscope with at least 6-8 Watt LED bulbs or else you will struggle to find the right area. The buccal ganglia is almost bikini-shaped as shown in the previous log from Ramakrishnan et al. 2014 and is seated directly behind the mouth. Best of luck!
By Nancy Sloan
Upon reading a new paper, I have determined a new location for the electrode (when I get that point in the experiment): the esophageal trunk! Ramakrishnan et al. in 2014 studied the buccal A cluster (BAC) cells that fill up the buccal ganglia, 40 in each. These cells vary in location, size, and the cluster that they’re in but essentially are responsible for telling different muscles to move, like opening the mouth or bringing the radula to the surface. All of these BACs have axonal projections through different nerves branching from the ganglia that we’ve talked about before: the lateral buccal neuron (LBN), the posterior buccal neuron (PBN), the esophageal trunks (ETs), and a few through the cerebro-buccal connective (CBC) that all then connect to different muscles. However, every one of these BAC projections goes through the esophageal trunks and none go through the ventro-buccal nerve. My plan was to attach the electrode to the trunk of the lateral and ventral buccal nerves, which is technically still okay, but only one nerve will be receiving signal. In the picture below from Ramakrishnan’s paper, you can see that there are connections in every neuron except for the VBN with the lightest grey view.
HENCE I will be placing the electrode around one of the esophageal trunks for a *hopefully* stronger signal. Until I get to the point of electrode placement, I am continuing the search for the buccal ganglia.
by Nancy Sloan