TY - JOUR
T1 - Second spatial derivative analysis of cortical surface potentials recorded in cat primary auditory cortex using thin film surface arrays
T2 - Comparisons with multi-unit data
AU - Fallon, James B.
AU - Irving, Sam
AU - Pannu, Satinderpall S.
AU - Tooker, Angela C.
AU - Wise, Andrew K.
AU - Shepherd, Robert K.
AU - Irvine, Dexter R.F.
PY - 2016/7/15
Y1 - 2016/7/15
N2 - Background: Current source density analysis of recordings from penetrating electrode arrays has traditionally been used to examine the layer- specific cortical activation and plastic changes associated with changed afferent input. We report on a related analysis, the second spatial derivative (SSD) of surface local field potentials (LFPs) recorded using custom designed thin-film polyimide substrate arrays. Results: SSD analysis of tone- evoked LFPs generated from the auditory cortex under the recording array demonstrated a stereotypical single local minimum, often flanked by maxima on both the caudal and rostral sides. In contrast, tone-pips at frequencies not represented in the region under the array, but known (on the basis of normal tonotopic organization) to be represented caudal to the recording array, had a more complex pattern of many sources and sinks. Comparison with existing methods: Compared to traditional analysis of LFPs, SSD analysis produced a tonotopic map that was more similar to that obtained with multi-unit recordings in a normal-hearing animal. Additionally, the statistically significant decrease in the number of acoustically responsive cortical locations in partially deafened cats following 6 months of cochlear implant use compared to unstimulated cases observed with multi-unit data (p = 0.04) was also observed with SSD analysis (p = 0.02), but was not apparent using traditional analysis of LFPs (p = 0.6). Conclusions: SSD analysis of surface LFPs from the thin-film array provides a rapid and robust method for examining the spatial distribution of cortical activity with improved spatial resolution compared to more traditional LFP recordings.
AB - Background: Current source density analysis of recordings from penetrating electrode arrays has traditionally been used to examine the layer- specific cortical activation and plastic changes associated with changed afferent input. We report on a related analysis, the second spatial derivative (SSD) of surface local field potentials (LFPs) recorded using custom designed thin-film polyimide substrate arrays. Results: SSD analysis of tone- evoked LFPs generated from the auditory cortex under the recording array demonstrated a stereotypical single local minimum, often flanked by maxima on both the caudal and rostral sides. In contrast, tone-pips at frequencies not represented in the region under the array, but known (on the basis of normal tonotopic organization) to be represented caudal to the recording array, had a more complex pattern of many sources and sinks. Comparison with existing methods: Compared to traditional analysis of LFPs, SSD analysis produced a tonotopic map that was more similar to that obtained with multi-unit recordings in a normal-hearing animal. Additionally, the statistically significant decrease in the number of acoustically responsive cortical locations in partially deafened cats following 6 months of cochlear implant use compared to unstimulated cases observed with multi-unit data (p = 0.04) was also observed with SSD analysis (p = 0.02), but was not apparent using traditional analysis of LFPs (p = 0.6). Conclusions: SSD analysis of surface LFPs from the thin-film array provides a rapid and robust method for examining the spatial distribution of cortical activity with improved spatial resolution compared to more traditional LFP recordings.
KW - Cochlear implant
KW - Cortical plasticity
KW - Local field potential
KW - Neural prosthesis
KW - Sensorineural hearing loss
UR - http://www.scopus.com/inward/record.url?scp=84962868855&partnerID=8YFLogxK
U2 - 10.1016/j.jneumeth.2016.04.004
DO - 10.1016/j.jneumeth.2016.04.004
M3 - Article
AN - SCOPUS:84962868855
SN - 0165-0270
VL - 267
SP - 14
EP - 20
JO - Journal of Neuroscience Methods
JF - Journal of Neuroscience Methods
ER -