scholarly journals Kindling Changes Burst Firing, Neural Synchrony and Tonotopic Organization of Cat Primary Auditory Cortex

2004 ◽  
Vol 14 (8) ◽  
pp. 827-839 ◽  
Author(s):  
P. A. Valentine
1994 ◽  
Vol 71 (1) ◽  
pp. 246-270 ◽  
Author(s):  
J. J. Eggermont

1. The effect of auditory stimulation with click trains, noise bursts, amplitude-modulated noise bursts, and amplitude-modulated tone bursts on the correlation of firing of 1,290 neuron pairs recorded on one or two electrodes in primary auditory cortex of the cat was investigated. A distinction was made between neural synchrony (the correlation under stimulus conditions) and neural correlation (the correlation under spontaneous or under stimulus conditions after correction for stimulus-related correlations). For neural correlation 63% of the single-electrode pairs showed a unilateral excitation component, often combined with a common-input peak, and only 11% of the dual electrode pairs showed this unilateral excitation. 2. Under poststimulus conditions the incidence of correlograms with clear peaks was high for single-electrode pairs (80–90% range) and somewhat lower for dual-electrode pairs (50–60% range). The strength of the neural correlation for poststimulus conditions, from 0.5 to 2 s after a 1-s stimulus, was comparable with that obtained for 15-min continuous silence, suggesting that aftereffects of stimulation had largely disappeared after 0.5 s. A stationary analysis of the correlation coefficient corroborated this. 3. Two stimulus-correction procedures, one based on the shift predictor and the other based on the joint peristimulus-time histogram (JPSTH) were compared. The mean value of the neural correlation under stimulus conditions obtained after applying the poststimulus time (PST) predictor was on average 20% larger than the mean value obtained after application of the shift predictor; however, this was not significantly different at the 0.05 level. There were no differences in the shape of the correlograms. This suggests that the less time-consuming shift predictor-based stimulus-correction procedure can be used for cortical neurons. 4. Under stimulus conditions neural correlation coefficients could be < or = 50% smaller than for spontaneous conditions. The strength of the stimulus-corrected neural correlation was inversely related to the relative size of the stimulus predictor (compared with the neural synchrony) and thus to the effectiveness of stimulation. This suggests that the assumption of additivity of stimulus and connectivity effects on neural synchrony is generally violated both for shift predictor and PST predictor procedures. 5. The neural correlogram peaks were narrower for single-electrode pairs than for dual-electrode pairs both under stimulus and spontaneous conditions. Under stimulus conditions the peaks were generally narrower than under spontaneous firing conditions.(ABSTRACT TRUNCATED AT 400 WORDS)


1993 ◽  
Vol 69 (4) ◽  
pp. 1292-1313 ◽  
Author(s):  
J. J. Eggermont ◽  
G. M. Smith ◽  
D. Bowman

1. Neural activity was recorded with two independent electrodes separated by 0.5-2 mm, aligned in parallel, and advanced perpendicular to the surface of the cat auditory cortex. Because the experiments were part of a study into laminar interaction the difference in recording depths for the two independently movable electrodes was never > 100 microns. Multi-unit activity on each electrode was separated on-line into single-unit spike-trains with a maximum variance spike sorting algorithm. Off-line controls on the quality of the spike-train separation were routinely performed. The first aim of this study was to describe the age dependence of spontaneous burst firing and to explore if and how it could be explained by age dependent changes in firing rate. The second aim was to investigate a potential layer dependence on burst firing. The third aim was to describe the effect of burst-removal procedures on the shape, strength, and width of the cross-correlogram and to investigate whether an age dependence in burst firing might account for the previously reported age dependence in correlation strengths. 2. Recordings were made from 237 single units from primary auditory cortex in nine adult cats and from 67 units in seven kittens age 10-52 days. The incidence of burst firing as a function of firing rate, age and depth of recording and unit characteristic frequency was investigated. In addition the effect of burst firing on the strength and width of the central peak in 471 neural pair correlograms was analyzed. 3. Burst firing could be distinguished at many different time scales; bursts lasting of the order of 10 s contained bursts with durations of the order of 1 s, which in turn contained bursts of 30-50-ms duration. The analysis in this paper was restricted to the short-duration bursts. 4. Burst firing on the short-time scale of 50 ms was characterized by relatively well defined intervals between the first two spikes (3-15 ms) followed by higher-order intervals with large spread (range 4-50 ms) but with increasing modal interval value. The typical adult five-spike burst template featured spikes at 0, 3.3, 14.6, 27.2, and 34.8 ms. Burst with fewer spikes showed larger intervals between the first three spikes. 5. The probability of occurrence of isolated spikes, pairs, triplets, etc. showed a power-law dependence on firing rate with a coefficient that was significantly lower than expected under Poisson firing conditions.(ABSTRACT TRUNCATED AT 400 WORDS)


1995 ◽  
Vol 674 (1) ◽  
pp. 147-152 ◽  
Author(s):  
Mitchell Steinschneider ◽  
David Reser ◽  
Charles E. Schroeder ◽  
Joseph C. Arezzo

1975 ◽  
Vol 100 (1) ◽  
pp. 188-191 ◽  
Author(s):  
Moise H. Goldstein ◽  
Moshe Abeles

Neuroreport ◽  
1996 ◽  
Vol 7 (3) ◽  
pp. 753-757 ◽  
Author(s):  
Jos J. Eggermont ◽  
Geoff M. Smith

2018 ◽  
Author(s):  
Huan-huan Zeng ◽  
Jun-feng Huang ◽  
Ming Chen ◽  
Yun-qing Wen ◽  
Zhi-ming Shen ◽  
...  

AbstractMarmoset has emerged as a useful non-human primate species for studying the brain structure and function. Previous studies on the mouse primary auditory cortex (A1) showed that neurons with preferential frequency tuning responses are mixed within local cortical regions, despite a large-scale tonotopic organization. Here we found that frequency tuning properties of marmoset A1 neurons are highly uniform within local cortical regions. We first defined tonotopic map of A1 using intrinsic optical imaging, and then used in vivo two-photon calcium imaging of large neuronal populations to examine the tonotopic preference at the single-cell level. We found that tuning preferences of layer 2/3 neurons were highly homogeneous over hundreds of micrometers in both horizontal and vertical directions. Thus, marmoset A1 neurons are distributed in a tonotopic manner at both macro- and microscopic levels. Such organization is likely to be important for the organization of auditory circuits in the primate brain.


1995 ◽  
Vol 74 (5) ◽  
pp. 1841-1855 ◽  
Author(s):  
D. M. Bowman ◽  
J. J. Eggermont ◽  
G. M. Smith

1. Neural activity was recorded extracellularly with two independent microelectrodes aligned in parallel and advanced perpendicular to isofrequency sheets in cat primary auditory cortex. Multiunit activity was separated into single-unit spike trains using a maximum variance spike sorting algorithm. Only units that demonstrated a high quality of sorting and a minimum spontaneous firing rate of 0.2 spikes/s were considered for analysis. The primary aim of this study was to describe the effect of periodic click train and broadband noise stimulation on short-time-scale (< or = 50 ms) bursts in the spike trains of single auditory cortical units and to determine whether stimulation influenced the occurrence, spike count, and/or temporal structure of burst firing relative to a spontaneous baseline. 2. Extracellular recordings were made in 20 juvenile and adult cats from 69 single auditory cortical units during click train stimulation and silence, and from 30 single units during noise stimulation and in silence. In an additional 15 single units the effect of both click train and noise stimulation was investigated. The incidence, spike count, and temporal structure of short-time-scale burst firing in the first 100 ms following stimulus presentation was compared with burst firing in the period starting 500 ms after stimulus presentation and with spontaneous burst firing. In addition, the serial dependence of interspike intervals within a burst was tested during periods of stimulation. 3. Burst firing was present in the stimulation, poststimulation, and spontaneous conditions. Longer bursts (consisting of > or = 3 spikes) were more commonly observed in the poststimulation and spontaneous conditions than in the stimulation condition. This effect was most pronounced during click stimulation. A period of elevated firing activity was present in a subset of units 0.5-1.5 s after stimulus presentation, indicating prolonged effects of stimulation on single-unit firing behavior. 4. For both stimuli, the proportion of single-unit responses composed of bursts was significantly greater in poststimulation and spontaneous periods than during stimulation. Burst rate was higher in post-click-train stimulation and spontaneous periods than during periods of click stimulation. The isolated spike rate was significantly higher during periods of noise and click stimulation than in the poststimulation and spontaneous periods. 5. An examination of the autocorrelograms and higher-order interspike interval histograms of single-unit responses during click train stimulation indicated that 25% of single-unit spike trains contained an excess of brief first-order intervals and 14% of spike trains contained a shortage of long higher-order interspike intervals relative to a spontaneous baseline. During noise stimulation, 10% of single-unit responses contained an excess of short intervals relative to baseline. Interspike intervals of short-duration bursts were not serially dependent during periods of stimulation. 6. A comparison of the autocorrelograms and higher-order interval histograms of single-unit responses in the poststimulation and spontaneous conditions indicated that 20% of single-unit spike trains contained an excess of short first-, second-, and third-order intervals following stimulation. This subgroups of single units could not be distinguished on the basis of the age of the animal or the depth at which the recording was made. 7. The low incidence of burst firing during stimulation opposes the view that bursts serve as a mechanism to emphasize or amplify particular stimulus-related responses in the presence of ongoing spontaneous activity in the primary auditory cortex. Moreover, there is little evidence to support the notion that brief bursts represent neural codes, because intraburst intervals are not serially dependent. It is suggested that pyramidal burst firing may be an effective way to evoke postsynaptic firing in inhibitory interneurons and subsequ


2014 ◽  
Author(s):  
Thomas Ragole ◽  
Erin Slason ◽  
Peter Teale ◽  
Martin Reite ◽  
Donald C. Rojas

Background: Disorganization of tonotopy in the auditory cortex has been described in schizophrenia. Subjects with schizophrenia show little to no spatial organization of responses to different tone frequencies in the auditory cortex. Previous studies have called into question the use of MEG and the M100 response to assess tonotopy. This study seeks to replicate prior results of tonotopic disorganization in schizophrenia compared to healthy controls. Methods: The tonotopic organization for 400 Hz and 4,000 Hz sound in 19 patients with schizophrenia and 11 comparison subjects was determined using MEG by examining the M100 auditory-evoked magnetic field dipole in primary auditory cortex. The equivalent current dipole locations were then mapped and compared. Results: The previous result of a lack of tonotopy in subjects with schizophrenia was partly replicated. In control subjects, the 400 Hz tone auditory evoked field was found anterior to the 4000 Hz in the primary auditory cortex. Conclusions: The lack of tonotopic organization of the auditory cortex is replicable in patients with schizophrenia and suggests that the architecture underlying tonotopy in the auditory cortex is disordered. This result suggests possible alteration in the organization of the auditory cortex, which may in turn influence higher order cognitive processes by altering the perception of incoming auditory stimuli.


2014 ◽  
Author(s):  
Thomas Ragole ◽  
Erin Slason ◽  
Peter Teale ◽  
Martin Reite ◽  
Donald C. Rojas

Background: Disorganization of tonotopy in the auditory cortex has been described in schizophrenia. Subjects with schizophrenia show little to no spatial organization of responses to different tone frequencies in the auditory cortex. Previous studies have called into question the use of MEG and the M100 response to assess tonotopy. This study seeks to replicate prior results of tonotopic disorganization in schizophrenia compared to healthy controls. Methods: The tonotopic organization for 400 Hz and 4,000 Hz sound in 19 patients with schizophrenia and 11 comparison subjects was determined using MEG by examining the M100 auditory-evoked magnetic field dipole in primary auditory cortex. The equivalent current dipole locations were then mapped and compared. Results: The previous result of a lack of tonotopy in subjects with schizophrenia was partly replicated. In control subjects, the 400 Hz tone auditory evoked field was found anterior to the 4000 Hz in the primary auditory cortex. Conclusions: The lack of tonotopic organization of the auditory cortex is replicable in patients with schizophrenia and suggests that the architecture underlying tonotopy in the auditory cortex is disordered. This result suggests possible alteration in the organization of the auditory cortex, which may in turn influence higher order cognitive processes by altering the perception of incoming auditory stimuli.


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