Multiple NeuroNexus probe designs (A2x32-5mm-25-200-177, A4x8-5mm-100-200-177, Buzsaki32 and Buzsaki64) were used by Andrew King’s lab at Oxford to record from primary sensory cortices, auditory thalamus and inferior colliculus in mice. NeuroNexus probes were also combined with optical stimulation for optogenetics experiments and with DiI dye for acute penetration histology in this study in Nature Communications. The results demonstrate that activity in somatosensory cortex caused by whisker stimulation suppresses sound-evoked activity in primary auditory cortex via the colliculus and thalamus, providing an example of subcortical pathways mediating intra-cortical communication.
Oran et. al used NeuroNexus linear probes (A1x16-10mm-100- 500-177) to evaluate the mechanisms of interhemispheric correlations and their dependence on behavioral state in the barrel cortex of awake mice. They showed that the interhemispheric correlations between the two barrel cortices depend on whisking state, and that the majority of these correlations were decreased during whisking compared to quiet wakefulness. Furthermore, despite general elevated firing rate in the whisking state, the activity of imaged callosal fibers was decreased. These results suggest the causal role of corpus callosum activity in mediating interhemispheric communication, as well as its dependence on the behavioral state of the animal.
Gaillet et al. used the NeuroNexus ECoG array, E32-1000-30-200, to record cortical activity along with a support vector machine classification algorithm to classify cortical responses originating from visual and electrical stimuli. They confirmed an increase in classification accuracy with increased center-to-center separation on patterned visual stimulation. Additionally, their results demonstrated the classification accuracy's dependence on the current amplitude, with higher accuracy at higher amplitudes. They also used a regression model to add a predictive capacity. Using a regression model, they showed that cortical activities elicited by electrical stimulation are meaningfully different, as it highlights features that vary in a linear manner, which can be expected from cortical activity patterns resulting from the stimulation of a gradually shifted portion of the visual field. These results represent a necessary, although not sufficient, condition for an optic nerve prosthesis to deliver vision with non-overlapping phosphene.
Results of Krichberger et al. paper using Neuronexus A1x32-5mm-25-177 linear probes along with optogenetics revealed how figure-ground modulation is necessary for perception. Also, they showed that the interactions between lower (V1) and higher areas of the visual cortex shape visual perception, enabling the co-selection of image elements that belong to a single figure and their segregation from the background.
Richter et al. explored the possibility of exchanging neural information between the brains of guinea pig and human. They determined characteristic frequency and recorded guinea pig inferior colliculus (ICC) neural response patterns to single spoken words with NeuroNexus A1x16-5mm-100-177 probes. The single-word spike trains were then played through corresponding electrodes of cochlear implants in human subjects. Subject performance on a few word recognition tests was better than chance, confirming the possibility of lexical information transmission from an animal auditory system to the human auditory system.
The Kraskov group used NeuroNexus 32-channel polytrodes (A1x32-Poly3-5mm-25s-177) to record fast and slow motor cortex (M1) pyramidal tract neurons (PTNs) in macaque. Their findings emphasize the importance of pairing electrophysiological and optogenetic approaches in classifying neurons into anatomical and morphological categories.
Viejo and Peyrache took advantage of NeuroNexus 8-shank polytrodes to sample from multiple sub-nuclei in the anterior thalamus in awake behaving mice. They were able to identify head direction (HD) cells in the AD nucleus and characterize firing rates and burstiness of HD and non-HD cells. Results demonstrated that AD HD cells specifically increase gain and coherence during hippocampal sharp wave ripples.
Congratulations to the Colonnese lab for their new publication in #eNeuro. They used Poly2 probes for dense acute recordings in mouse pup V1 to demonstrate that retinal input does not govern developmental increases in cortical activity. Their recordings were done with the NeuroNexus SmartBox system. Learn more about the updated system here.
Using NeuroNexus linear arrays, dense sampling through the auditory cortex enabled computation of bipolar derivation LFPs for supragranular and infragranular layers. LFPs were also sampled across the posterior auditory field within the ectosylvian sulcus. This study is a great example of using NeuroNexus probes to target hard-to-reach areas.
There's a new paper out from Dr Tracy Cui's lab in which NeuroNexus probes were tested under precise stimulation conditions. We are proud to provide devices with consistent electrode site properties to enable studies like this. Congratulations Sally Zheng and co-authors!
It's always exciting when translational studies come out with NeuroNexus as part of the basic science.
Congratulations to the authors!
Morgan Urdaneta's publication out of Kevin Otto's lab is here! Read it to see how NeuroNexus linear arrays enabled them to define tachaxies across cortical layers.
Hot off the presses! We're excited about this new publication featuring a one-of-a-kind custom NeuroNexus silicon microelectrode. This probe has two different shank lengths, as well as a combination of recording and simulation electrode sites.
This collaboration between the Dietmar Schmitz and Gyorgy Buzsaki labs utilized 32-channel and 256-channel multi-shank NeuroNexus probes and optoelectrodes. The geometry of the probes enabled positioning shanks in the mouse hippocampus/dentate gyrus, subiculum and granular retrosplenial cortex simultaneously. Through acute electrophysiology and optogenetic manipulation, this team defined a pathway by which sharp wave ripples communicate from the hippocampus to cortex.
This publication in eNeuro provides highlights valuable data obtained from acute recordings with standard NeuroNexus catalog probes in macaque visual cortices. The researchers covered the skull with acrylic resin, performed a craniotomy through the resin, then inserted silicon probes through a slit in the dura. Re-use of the probes and multiple recordings in the same animals were achieved with this method. Original recordings were published here. The present study’s computational results suggest that saliency of visual stimuli are represented in primary visual cortex.
Neuronexus A2x16-10mm-150-500-177-A32, 2-shank laminar probes were used to record the control frequency tuning profile of the guinea pig inferior colliculus. The animals were then acutely deafened and probe recordings were used to characterize inferior colliculus activity during use of cochlear implants with different stimulation profiles. This study in Hearing Research points to a solution for reducing channel interactions in cochlear implants, with the potential to improve speech detection for cochlear implant users.
Koch et al. from John Wolf’s Lab published their study on functional status of hippocampal neurons after traumatic brain injury (TBI). A NeuroNexus 32-channel probe (A1X32-Poly2-5mm-50s-177-H32) was used for laminar recording in CA1 in a rat TBI model. They reported that hippocampal CA1 single-unit activity post-TBI can maintain a normal firing rate despite significantly reduced, layer-specific loss of input. However, maintaining normal synchronization to the dominant oscillations within the hippocampus is impaired.
Lipinski et al. published their study on adult neuron identity recently! A NeuroNexus 32-channel linear array with 50um site spacing (approx 1.5mm recording span) was used to record simultaneously from the CA1 and dentate gyrus in mutant mice with an inducible genetic mutation to delete two transcriptional co-activators. Across acute multi-channel recordings, drops in activity were observed within 2 weeks of genetic ablation.