Study of the cortical representation of whisker frequency selectivity using voltage-sensitive dye optical imaging

Abstract

The facial whiskers of rodents act as a high-resolution tactile apparatus that allow the animal to detect the finest details of its environment. Previously it was shown that whisker-sensitive neurons in the somatosensory cortex show frequency selectivity to small amplitude stimuli, An intravital voltage-sensitive dye optical imaging (VSDi) method in combination with the different frequency whisker stimulation was used in order to visualize neural activity in the mice somatosensory cortex in response to the stimulation of a single whisker by different frequencies. Using the intravital voltage-sensitive dye optical imaging (VSDi) method in combination with the different frequency whisker stimulation we visualized neural activity in the mice somatosensory cortex in response to the stimulation of a single whisker by different frequencies. We found that whisker stimuli with different frequencies led to different optical signals in the barrel field. Our results provide evidence that different neurons of the barrel cortex have different frequency preferences. This supports prior research that whisker deflections cause responses in cortical neurons within the barrel field according to the frequency of the stimulation. Many studies of the whisker frequency selectivity were performed using unit recording but to map spatial organization, imaging methods are essential. In the work described in the present paper, we take a serious step toward detailed functional mapping of the somatosensory cortex using VSDi. To our knowledge, this is the first demonstration of whisker frequency sensitivity and selectivity of barrel cortex neurons with optical imaging methods.

Tapping Into the Language of Touch: Using Non-invasive Stimulation to Specify Tactile Afferent Firing Patterns

“…Other groups are combining animal experiments with single unit cortical recording and behavioural experiments to understand the neural code for tactile information at higher levels of the nervous system (Harvey et al, 2013). Studies in the barrel cortex of mice, an important tactile area for whisker inputs in rodents, suggests that strong integration of whisker movements occurs over a short time period of less than 25 ms (Stüttgen and Schwarz, 2010;Estebanez et al, 2012;Tsytsarev et al, 2016), which fits well with our observations. Weaker integration of one or two inter-spike intervals over longer time periods has also been reported (Pitas et al, 2016), which supports the importance of temporal pattern encoding, and may underlie the recognition of the burst gap intervals.…”

Bilateral sensory disturbance after cortical spreading depression revealed by fluorescence imaging of voltage‐sensitive dye

“…We have investigated the altered bilateral sensory processing produced by CSD using voltage‐sensitive dye (VSD) imaging under somatosensory and cortical surface stimulation (CSS) in mice. VSD imaging can represent neuronal electrical activities at high spatial and temporal resolution , which has previously been applied on the neocortex of mice to reveal the interactions between different pathways during sensory control . We first observed the selective deficits of bilateral sensory‐evoked responses produced by CSD.…”

Whisker Contact Detection of Rodents Based on Slow and Fast Mechanical Inputs

“…By analogy, FA mechanoreceptors of rodents likely have an optimal response around the whisker's resonance frequency (Andermann et al, 2004). Recent Voltage Sensitive Optical Imaging (VSDi) experiments have also shown that the neural activity in the barrel cortex, in response to oscillatory excitation of the whisker was enhanced when the excitation frequency is about 300 Hz (Tsytsarev et al, 2016). Since f w is much lower than f 0 by more than an order of magnitude, one may expect that whisking in air will trigger less activity in FA neurons.…”