Spike Patterns in the Super-Critical Bahri—Coron Problem

2002 ◽  
pp. 89-103
Author(s):  
M. del Pino ◽  
P. Felmer ◽  
M. Musso
Keyword(s):  
Spike Patterns

scholarly journals Differential Effects of Open- and Closed-Loop Intracortical Microstimulation on Firing Patterns of Neurons in Distant Cortical Areas

2019 ◽  
Vol 30 (5) ◽  
pp. 2879-2896 ◽  
Author(s):  
Alberto Averna ◽  
Valentina Pasquale ◽  
Maxwell D Murphy ◽  
Maria Piera Rogantin ◽  
Gustaf M Van Acker ◽  
...  
Keyword(s):  
Closed Loop ◽  
Activity Patterns ◽  
Brain Lesion ◽  
Progressive Increase ◽  
Intracortical Microstimulation ◽  
Behavioral Recovery ◽  
Firing Patterns ◽  
Electrical Microstimulation ◽  
Spike Patterns ◽  
Activity Dependent

Abstract Intracortical microstimulation can be used successfully to modulate neuronal activity. Activity-dependent stimulation (ADS), in which action potentials recorded extracellularly from a single neuron are used to trigger stimulation at another cortical location (closed-loop), is an effective treatment for behavioral recovery after brain lesion, but the related neurophysiological changes are still not clear. Here, we investigated the ability of ADS and random stimulation (RS) to alter firing patterns of distant cortical locations. We recorded 591 neuronal units from 23 Long-Evan healthy anesthetized rats. Stimulation was delivered to either forelimb or barrel field somatosensory cortex, using either RS or ADS triggered from spikes recorded in the rostral forelimb area (RFA). Both RS and ADS stimulation protocols rapidly altered spike firing within RFA compared with no stimulation. We observed increase in firing rates and change of spike patterns. ADS was more effective than RS in increasing evoked spikes during the stimulation periods, by producing a reliable, progressive increase in stimulus-related activity over time and an increased coupling of the trigger channel with the network. These results are critical for understanding the efficacy of closed-loop electrical microstimulation protocols in altering activity patterns in interconnected brain networks, thus modulating cortical state and functional connectivity.

Cortical Representation of Auditory Space: Information-Bearing Features of Spike Patterns

2002 ◽  
Vol 87 (4) ◽  
pp. 1749-1762 ◽  
Author(s):  
Shigeto Furukawa ◽  
John C. Middlebrooks
Keyword(s):  
Sound Source ◽  
Neuronal Response ◽  
Source Location ◽  
Spike Timing ◽  
Spike Count ◽  
Cortical Representation ◽  
Auditory Space ◽  
Transmitted Information ◽  
Related Information ◽  
Spike Patterns

Previous studies have demonstrated that the spike patterns of cortical neurons vary systematically as a function of sound-source location such that the response of a single neuron can signal the location of a sound source throughout 360° of azimuth. The present study examined specific features of spike patterns that might transmit information related to sound-source location. Analysis was based on responses of well-isolated single units recorded from cortical area A2 in α-chloralose-anesthetized cats. Stimuli were 80-ms noise bursts presented from loudspeakers in the horizontal plane; source azimuths ranged through 360° in 20° steps. Spike patterns were averaged across samples of eight trials. A competitive artificial neural network (ANN) identified sound-source locations by recognizing spike patterns; the ANN was trained using the learning vector quantization learning rule. The information about stimulus location that was transmitted by spike patterns was computed from joint stimulus-response probability matrices. Spike patterns were manipulated in various ways to isolate particular features. Full-spike patterns, which contained all spike-count information and spike timing with 100-μs precision, transmitted the most stimulus-related information. Transmitted information was sensitive to disruption of spike timing on a scale of more than ∼4 ms and was reduced by an average of ∼35% when spike-timing information was obliterated entirely. In a condition in which all but the first spike in each pattern were eliminated, transmitted information decreased by an average of only ∼11%. In many cases, that condition showed essentially no loss of transmitted information. Three unidimensional features were extracted from spike patterns. Of those features, spike latency transmitted ∼60% more information than that transmitted either by spike count or by a measure of latency dispersion. Information transmission by spike patterns recorded on single trials was substantially reduced compared with the information transmitted by averages of eight trials. In a comparison of averaged and nonaveraged responses, however, the information transmitted by latencies was reduced by only ∼29%, whereas information transmitted by spike counts was reduced by 79%. Spike counts clearly are sensitive to sound-source location and could transmit information about sound-source locations. Nevertheless, the present results demonstrate that the timing of the first poststimulus spike carries a substantial amount, probably the majority, of the location-related information present in spike patterns. The results indicate that any complete model of the cortical representation of auditory space must incorporate the temporal characteristics of neuronal response patterns.

scholarly journals Effects of Cellular Adaptations to Partial Demyelination on Spike Patterns in a Model Axon

2010 ◽  
Vol 98 (3) ◽  
pp. 140a
Author(s):  
Jay S. Coggan ◽  
Terrence J. Sejnowski
Keyword(s):  
Spike Patterns

Sensitivity of Auditory Cortical Neurons to the Locations of Leading and Lagging Sounds

2005 ◽  
Vol 94 (2) ◽  
pp. 979-989 ◽  
Author(s):  
Brian J. Mickey ◽  
John C. Middlebrooks
Keyword(s):  
Unit Activity ◽  
Cortical Neurons ◽  
Precedence Effect ◽  
Related Information ◽  
Sound Levels ◽  
Transmission Of Information ◽  
Discrete Responses ◽  
Temporal Firing ◽  
Spike Patterns ◽  
Awake Cats

We recorded unit activity in the auditory cortex (fields A1, A2, and PAF) of anesthetized cats while presenting paired clicks with variable locations and interstimulus delays (ISDs). In human listeners, such sounds elicit the precedence effect, in which localization of the lagging sound is impaired at ISDs ≲10 ms. In the present study, neurons typically responded to the leading stimulus with a brief burst of spikes, followed by suppression lasting 100–200 ms. At an ISD of 20 ms, at which listeners report a distinct lagging sound, only 12% of units showed discrete lagging responses. Long-lasting suppression was found in all sampled cortical fields, for all leading and lagging locations, and at all sound levels. Recordings from awake cats confirmed this long-lasting suppression in the absence of anesthesia, although recovery from suppression was faster in the awake state. Despite the lack of discrete lagging responses at delays of 1–20 ms, the spike patterns of 40% of units varied systematically with ISD, suggesting that many neurons represent lagging sounds implicitly in their temporal firing patterns rather than explicitly in discrete responses. We estimated the amount of location-related information transmitted by spike patterns at delays of 1–16 ms under conditions in which we varied only the leading location or only the lagging location. Consistent with human psychophysical results, transmission of information about the leading location was high at all ISDs. Unlike listeners, however, transmission of information about the lagging location remained low, even at ISDs of 12–16 ms.

scholarly journals Spatial Sensitivity in Field PAF of Cat Auditory Cortex

2003 ◽  
Vol 89 (6) ◽  
pp. 2889-2903 ◽  
Author(s):  
G. Christopher Stecker ◽  
Brian J. Mickey ◽  
Ewan A. Macpherson ◽  
John C. Middlebrooks
Keyword(s):  
Auditory Cortex ◽  
Primary Auditory Cortex ◽  
Median Plane ◽  
Stimulus Location ◽  
Population Coding ◽  
Broadband Noise ◽  
Spatial Sensitivity ◽  
Neural Ensembles ◽  
Artificial Neural Network Ann ◽  
Spike Patterns

We compared the spatial tuning properties of neurons in two fields [primary auditory cortex (A1) and posterior auditory field (PAF)] of cat auditory cortex. Broadband noise bursts of 80-ms duration were presented from loudspeakers throughout 360° in the horizontal plane (azimuth) or 260° in the vertical median plane (elevation). Sound levels varied from 20 to 40 dB above units' thresholds. We recorded neural spike activity simultaneously from 16 sites in field PAF and/or A1 of α-chloralose-anesthetized cats. We assessed spatial sensitivity by examining the dependence of spike count and response latency on stimulus location. In addition, we used an artificial neural network (ANN) to assess the information about stimulus location carried by spike patterns of single units and of ensembles of 2–32 units. The results indicate increased spatial sensitivity, more uniform distributions of preferred locations, and greater tolerance to changes in stimulus intensity among PAF units relative to A1 units. Compared to A1 units, PAF units responded at significantly longer latencies, and latencies varied more strongly with stimulus location. ANN analysis revealed significantly greater information transmission by spike patterns of PAF than A1 units, primarily reflecting the information transmitted by latency variation in PAF. Finally, information rates grew more rapidly with the number of units included in neural ensembles for PAF than A1. The latter finding suggests more accurate population coding of space in PAF, made possible by a more diverse population of neural response types.

SU-FF-T-348: Optimize Spike Patterns For An Embedded Boost Technique For Gamma Knife Radiosurgery

2006 ◽  
Vol 33 (6Part12) ◽  
pp. 2126-2126
Author(s):  
L Ma ◽  
D Larson ◽  
P Petti ◽  
C Chuang ◽  
L Verhey
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Spike Patterns
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