July 30, 2015
The Vector Array™ is an all-new neural probe design optimized for large animal deep brain applications (e.g. non-human primate, porcine, etc.).
Already being successfully used in labs, the Vector Array™ can be customized for different applications, taking advantage of the versatility of NeuroNexus' silicon microelectrode technology. Here are some first-hand accounts from three research groups on the work they have been doing with the Vector Array™.
Macaque Frontal Eye Field (FEF)
Macaque MRI co-registered with grid, showing sampling across depth with LFP and spiking data
A group in Tennessee is using a 32-channel Vector Array™ with 100 µm site spacing to record from the Frontal Eye Field (FEF) of the prefrontal cortex of macaque monkeys during visual tasks. According to a member of the lab, "the Vector probe overcomes previous limitations and allows us to sample a spatial 'slice' of FEF with each penetration, which we co-register to MRI images that are aligned with our chamber grids, allowing us to map the spatial distribution of responses and observe how response properties change across locations and with respect to cortical layers."
"The figure shows the MRI for one of our monkeys (bonnet macaque) with grid co-registered. With the MRI map in place, we can select a location, and sample across depth while recording LFP and spiking data, which are plotted to the right of the MRI images. These plots show 1) the spatial distribution of LFP plots and 2) the spatial distributions of different cell types across depths/contacts (indicated by V, VM, M, classified by spiking characteristics), aligned on a schematic cortical layer representation of FEF. With this setup, we can go back to specific locations across days (indicated by Day 1 and Day 2 in response maps), and begin to characterize the spatial layout of FEF responses, as well as characterizing the source of the spatially distributed LFP signal. The inset at the top right of the figure shows the quality of sorts we are able to obtain using the Vector Array, which is critical for our ability to accurately characterize the response properties of the various cell types."
Porcine Hippocampal Laminar Fields
Left: Custom-designed 32 channel Vector Array, with seven tetrode clusters. Right: 10 second signal sample corresponding to the recording location on Vector Array.
A second group in Pennsylvania is using a custom-designed 32-channel Vector Array™ with 28 of the sites clustered into seven tetrodes to record from the hippocampus of a porcine model. According to a member of the lab, "The electrodes have been working very well for field recordings with beautiful noise free recordings from the awake behaving pig in a contained room (11X11) behavioral space."
Primate Cortex Laminar Recordings
Left: Poly2 Site layout at the tip of a 32 channel Vector Array. Right: Single units recorded by the Vector Array, corresponding to recording site location.
A group in Texas has been using a 32-channel Vector Array™ with sites arranged in a Poly2 formation to do laminar recordings from both the cortex (V1), as well as deeper structures. According to a member of the lab, "We've been working with the Polytrode Vector probes for a few months now and are very enthusiastic about the results! We can easily see your depth probes becoming the standard in non-chronic primate electrophysiology recordings over all the other available probes, especially as the field moves towards more sensitive ways of probing neural circuits by recording from all layers simultaneously, for example, which your probes would allow. It will be a great way to extend the value and use of electrophysiological recordings in a time of significant advancements in optical recording as well, by creating an advantage that optical imaging does not yet allow - complete laminar recordings."