scholarly journals A template-matching algorithm for laminar identification of cortical recording sites from evoked response potentials

2019 ◽  
Author(s):  
Giulio Matteucci ◽  
Margherita Riggi ◽  
Davide Zoccolan
Keyword(s):  
Template Matching ◽  
Current Source ◽  
Evoked Response ◽  
Spatiotemporal Pattern ◽  
Manual Annotation ◽  
Subjective Judgment ◽  
Visual Identification ◽  
Alternative Approach ◽  
Human Operators ◽  
Evoked Response Potentials

AbstractIn recent years, the advent of the so-called silicon probes has made it possible to homogeneously sample spikes and local field potentials (LFPs) from a regular grid of cortical recording sites. In principle, this allows inferring the laminar location of the sites based on the spatiotemporal pattern of LFPs recorded along the probe, as in the well-known current source-density (CSD) analysis. This approach, however, has several limitations, since it relies on visual identification of landmark features (i.e., current sinks and sources) by human operators – features that can be absent from the CSD pattern if the probe does not span the whole cortical thickness, thus making manual labelling harder. Furthermore, as any manual annotation procedure, the typical CSD-based workflow for laminar identification of recording sites is affected by subjective judgment undermining the consistency and reproducibility of results. To overcome these limitations, we developed an alternative approach, based on finding the optimal match between the LFPs recorded along a probe in a given experiment and a template LFP profile that was computed using 18 recording sessions, in which the depth of the recording sites had been recovered through histology. We show that this method can achieve an accuracy of 79 µm in recovering the cortical depth of recording sites and a 76% accuracy in inferring their laminar location. As such, our approach provides an alternative to CSD that, being fully automated, is less prone to the idiosyncrasies of subjective judgment and works reliably also for recordings spanning a limited cortical stretch.New and noteworthyKnowing the depth and laminar location of the microelectrodes used to record neuronal activity from the cerebral cortex is crucial to properly interpret the recorded patterns of neuronal responses. Here we present an innovative approach that allows inferring such properties with high accuracy and in an automated way (i.e., without the need of visual inspection and manual annotation) from the evoked response potentials (ERPs) elicited by sensory (e.g., visual) stimuli.

Laminar excitability cycles in neocortex

1991 ◽  
Vol 65 (4) ◽  
pp. 891-898 ◽  
Author(s):  
D. S. Barth ◽  
S. Di
Keyword(s):  
Time Course ◽  
Microelectrode Array ◽  
Cortical Excitability ◽  
Initial Period ◽  
Current Source ◽  
Conditioning Stimulus ◽  
Principal Component ◽  
Evoked Response ◽  
Rat Somatosensory Cortex ◽  
The Relationship

1. Laminar field potentials produced by paired electrocortical stimuli were recorded with a linear microelectrode array inserted perpendicular to the surface of rat somatosensory cortex. Current source-density (CSD) distributions of the direct cortical response (DCR) were computed from the potential profiles. Principal component analysis (PCA) was used to estimate the time course of evoked transmembrane currents of putative pyramidal cell populations in the supragranular and infragranular layers. 2. Both supra- and infragranular cells displayed an initial period after the conditioning stimulus in which test stimuli produced subnormal evoked response amplitudes. This was followed in both layers by a long period of supernormal then subnormal responses and a second period of supernormal responses. 3. The main laminar difference encountered was a general shortening of all phases of the excitability cycle in the supragranular cells. 4. Excitability cycles in the supra- and infragranular layers closely followed the morphology of average evoked responses to the conditioning stimulus alone. These results and physiological support to the validity of lamina-specific evoked response waveforms derived from combined CSD and PCA analysis of extracellular potential measurements. 5. The relationship between evoked potential amplitude changes and cortical excitability is discussed.

Direct and indirect visual inputs to superficial layers of cat superior colliculus: a current source-density analysis of electrically evoked potentials

1983 ◽  
Vol 49 (5) ◽  
pp. 1075-1091 ◽  
Author(s):  
B. Freeman ◽  
W. Singer
Keyword(s):  
Visual Cortex ◽  
Optic Nerve ◽  
Superior Colliculus ◽  
Current Source ◽  
Afferent Fiber ◽  
Synaptic Activity ◽  
Spatiotemporal Pattern ◽  
Visual Inputs ◽  
Electrolytic Lesions ◽  
Cat Superior Colliculus

1. The spatiotemporal pattern of visual inputs to the stratum griseum superficiale (SGS) and stratum opticum (SO) of the cat superior colliculus (SC) has been determined by an analysis of the current sinks occurring during postsynaptic activity following stimulation of each optic nerve (ON) and the optic chiasm (OX). Electrolytic lesions were used to determine the locations of the five major current sinks. 2. Direct SC afferents from the contralateral ON induced three current sinks whose maxima were located a) in the upper part of the SGS, b) in the middle part of the SGS, and c) in the lower part of the SGS and upper part of the SO. These three sinks were generated by three afferent fiber groups conducting in the optic nerve with modal and maximum velocities, respectively, of a) 4 and 5 m/s (slow W-group), b) 7 and 10 m/s (fast W-group), and c) 32 and 43 m/s (Y-group). 3. Indirect SC inputs from the contralateral ON via the ipsilateral visual cortex were identified by comparing the pattern of current sinks generated by OX stimulation before and after cortical ablation. The most prominent and fastest indirect sink (Y-group) was found in ;the lower half of the SGS and uppermost part of the SO. Low-amplitude, long-latency indirect current sinks were also found in the upper and lower thirds of the SGS. 4. The principal conclusions of this report are first, that the SGS is divisible into three physiologic regions according to the spatiotemporal pattern of excitatory synaptic activity generated by the afferent inputs and second, that there is a spatiotemporal matching of the direct collicular afferents from the contralateral retina and the indirect retinal afferents relaying through the ipsilateral visual cortex.

scholarly journals Innovative Methodology

2020 ◽  
Vol 124 (1) ◽  
pp. 102-114
Author(s):  
Giulio Matteucci ◽  
Margherita Riggi ◽  
Davide Zoccolan
Keyword(s):  
Cerebral Cortex ◽  
Neuronal Activity ◽  
Visual Inspection ◽  
Visual Stimuli ◽  
High Accuracy ◽  
Innovative Approach ◽  
Manual Annotation ◽  
Neuronal Responses ◽  
Innovative Methodology ◽  
Evoked Response Potentials

Knowing the depth and laminar location of the microelectrodes used to record neuronal activity from the cerebral cortex is crucial to properly interpret the recorded patterns of neuronal responses. Here, we present an innovative approach that allows inferring such properties with high accuracy and in an automated way (i.e., without the need of visual inspection and manual annotation) from the evoked response potentials elicited by sensory (e.g., visual) stimuli.

Electrophysiological evidence for overlapping dominant and latent inputs to somatosensory cortex in squirrel monkeys

1995 ◽  
Vol 74 (2) ◽  
pp. 722-732 ◽  
Author(s):  
C. E. Schroeder ◽  
S. Seto ◽  
J. C. Arezzo ◽  
P. E. Garraghty
Keyword(s):  
Ulnar Nerve ◽  
Radial Nerve ◽  
Current Flow ◽  
Current Source ◽  
Squirrel Monkeys ◽  
Spatiotemporal Pattern ◽  
Nerve Section ◽  
Multiunit Activity ◽  
Preferential Access ◽  
Area 3B

1. The pattern of reorganization in area 3b of adult primates after median or ulnar nerve section suggests that somatic afferents from the dorsum of the hand, carried by the radial nerve, have preferential access to the cortical territories normally expressing glabrous inputs carried by the median and ulnar nerves. A likely mechanism underlying preferential access is preexisting, but silent, radial nerve inputs to the glabrous region of cortex. 2. We tested this by comparing the effects of electrical stimulation of median or ulnar versus radial nerves, on responses in the hand representation of area 3b. Laminar current source density and multiunit activity profiles were sampled with the use of linear array multicontact electrodes spanning the laminae of area 3b. Data were obtained from three squirrel monkeys anesthetized during recording. 3. Compared with colocated median or ulnar nerve responses, the radial nerve response had 1) an initial short-latency response in the middle laminae that was subtle; there was a small transmembrane current flow component without a discernable multiunit activity correlate; and 2) a laminar sequence and distribution of activity that was similar to those of the median or ulnar nerve responses (i.e., initial activation of the middle, followed by upper and lower laminae), but the significant current flow and multiunit response to radial nerve stimulation occurs 12–15 ms later. 4. Normal corepresentation of nondominant dorsum hand (radial) inputs with the dominant (median or ulnar) inputs in the glabrous hand surface representation provides a clear vehicle for the biased patterns of reorganization occurring after peripheral nerve section. The initial, “subtle” activity phase in the nondominant response is believed to reflect intracortical inhibition, and the later “significant” response phase, a rebound excitation, possibly compounded by an indirect or extralemniscal input. The spatiotemporal pattern of nondominant input is proposed to play a role in normal somatosensory perception.

P300 Evoked Response Potentials Patterns in Different Complex Concussion Phenotypes

Neurology ◽  
2021 ◽  
Vol 98 (1 Supplement 1) ◽  
pp. S4.2-S5
Author(s):  
Basil Ike ◽  
Landon Watts ◽  
David S. Oakley ◽  
Monica Pita ◽  
Mohammad Mortazavi
Keyword(s):  
Retrospective Study ◽  
Neck Pain ◽  
Mixed Type ◽  
Statistical Significance ◽  
Evoked Response ◽  
Entire Group ◽  
Post Injury ◽  
Neurologic Disorders ◽  
Symptom Scores ◽  
Evoked Response Potentials

ObjectiveDetermine the utility of P300 Evoked Response Potentials (ERP) voltage patterns in predicting phenotypical sequelae of patients with complex concussions or Persistent Post Concussive Symptoms (PPCS).BackgroundERPs have been used to aid in the diagnosis of multiple neurologic disorders. They have also been recently used in the evaluation of concussions.Design/MethodsA retrospective study of 54 patients, 10–71 year (mean age 29.6 yrs), with PPCS were tested between 6 and 12 weeks post-injury using the standard oddball audio P300 ERP protocol with measures extracted including best central parietal P300 ERP. PPCS Phenotyping was completed in each patient using a standardized post-concussive questionnaire and Rivermead method for 5 primary phenotypes and mixed type.ResultsP300 average Voltage for the entire group was 11.6 mV. Overall, these were significantly lower than age-matched non concussed controls whose average voltage was 16.3 mV (p < 0.0001). Average P300 voltages for each phenotype: Cognition- 14.1 mV, Vestibular- 8.6 mV, Headache- 11.1 mV, Mood- 13.6 mV, Neck Pain- 9.6 mV, Visual- 9.8 mV, Mixed- 6.9 mV, Mixed and Vestibular phenotypes demonstrated the lowest average voltage potentials (6.9 mV and 8.6 mV respectively) which coincided with higher average symptom scores (70.5 and 54.5 respectively). Cognition and Mood demonstrated the highest average voltage potentials (14.1 mV and 13.6 nV respectively), which coincided with lower average symptom scores (40.3 and 48.7, respectively). Mood (13.6 mV) was the lowest average symptom score in the group at 40.3 and Mixed (6.9 mV) was highest at 70.5. Comparing phenotypes against one other, mixed vs mood (p = 0.03), cognition vs vestibular (p = 0.02), and cognition vs mixed (p = 0.009) showed statistical significance.ConclusionsP300 ERPs may help identify persistent abnormal complex concussion neurophysiology. ERPs can also potentially exhibit phenotype specific patterns and be a useful tool in helping differentiate more somatic/physiologic vs mood-based phenotypes. This can ultimately lead in the aid in diagnosis, prognosis, subtyping, and targeted phenotype management.

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