Spatiotemporal analysis of prepyriform, visual, auditory, and somesthetic surface EEGs in trained rabbits
Spatiotemporal analysis of prepyriform, visual, auditory, and somesthetic surface EEGs in trained rabbits
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DOI：
10.1152/jn.1996.76.1.520
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发表时间：
1996-07-01
影响因子：
2.5
通讯作者：
Lenhart, MD
中科院分区：
文献类型：
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作者：
Barrie, JM;Freeman, WJ;Lenhart, MD
1。对64个轨迹的脑电图（EEG）计算的空间集合平均值，同时从8 x 8阵列中记录了前皮层皮质（PPC）以及视觉，体式，体细胞和听觉皮层的硬膜外表面上。他们揭示了每个数组中的一个公共波形。对波形的空间幅度调制（AM）的检查显示在短时间段中可分类的空间模式。呈现相同条件刺激以及在不同刺激的试验之间的试验中，AM模式在试验中有所不同。2。 PPC EEG显示与呼吸节奏相关。新皮层脑电图没有3。 PPC脑电图的时间合奏减弱了振荡爆发，表明嗅觉γ振荡（20-80 Hz）并未与刺激递送时代相锁定，而是对吸入。跨试验的新皮质记录的时机平均值显示，刺激到来后30-50毫秒开始，平均诱发电位。4。来自前后PPC EEG段的平均时间快速傅立叶变换（FFT）功率谱密度（PSD）显示嗅觉突发中的伽马活性峰5。在绘制对数频率的绘制时，来自前后新皮质脑电图的平均时间FFT PSD的对数显示出1/f型光谱在刺激前和刺激后段的阴性/厌恶状态刺激（CS-）和阳性/阳性/阳性/阳性/呈阳性/f-type光谱奖励条件刺激（CS+）。等式回归中的alpha'-和beta'-coefficients。在刺激前和刺激后段之间，平均PSD的平均PSD显着差异，这是由于诱发电位，但在CS-和CS+刺激段之间没有显着差异。6。在1/F域（20-100 Hz）中的所有频率箱中，时空模式都是不变的。 2至20 Hz结构域中的时空模式逐渐与频率降低的不变模式不同。7。在空间频域中，从前后新皮质的脑电图段的平均空间FFT功率谱的对数，当针对对数空间频率绘制时，在最低空间频率下单调地降低到最低的空间频率，从而向下弯曲到线性1/1/1/1// F光谱域。 1/F光谱域中的这条曲线从PPC中的0.133延伸至0.880循环/mm，新皮层的曲线从0.095延伸至0.095循环/mm .8。 FFT和主成分分析方法（PCA）脑电图分解用于从阵列中提取所有64个EEG的广谱波形。 FFT和PCA组件的AM模式是通过回归得出的。通过互相关显示了它们，以产生相互等效的空间模式，并通过计算64个均方根幅度的计算。9。每个空间AM模式通过1 x 64列矢量和64空间的点表示。类似的模式形成簇，不同的模式给出了多个簇。设计了统计检验，以评估64个空间中欧几里得距离度量的差异。10。在数字时间和空间滤波器优化后，在刺激后数据的离散时间段中发现了CS-与CS+试验的显着空间模式分类（低于20的1％置信度限制）。11。将分析窗口持续时间从10到500毫秒改变，窗口长度为120毫秒，是模式分类的最佳选择。随后以20毫秒的重叠间隔将一个120毫秒的窗口跨过每个记录。窗口上有明显的CS+/CS-差异发生的窗户持续了50-200毫秒，并在刺激后时期分开100-200毫秒。12。新皮层空间模式在加强意义上的反转下发生了变化，表明在刺激方面缺乏不变性以及对上下文和学习的依赖，如先前针对嗅球和PPC.13所示。有助于分类的脑电图数据均匀地分布在宽的时间和空间光谱带上以及电极的空间阵列。模式可以用只有16个通道解决。没有任何渠道对分类的贡献或多或少都比其他任何渠道。14。神经活动模式的快速波形，快速的全球状态变化，上下文依赖性以及神经活动的均匀分布表明，在感知过程中形成的神经事件是由古皮质和新皮层中的合作种群动态构建的。到目前为止
1. Spatial ensemble averages were computed for 64 traces of electroencephalograms (EEGs) simultaneously recorded from 8 x 8 arrays over the epidural surfaces of the prepyriform cortex (PPC) and visual, somatic, and auditory cortices. They revealed a common waveform across each array. Examination of the spatial amplitude modulation (AM) of the waveform revealed classifiable spatial patterns in short time segments. The AM patterns varied within trials after presentation of identical conditioned stimuli, and also between trials with differing stimuli.2. PPC EEGs revealed strong correlates with the respiratory rhythm; neocortical EEGs did not.3. Time ensemble averaging of the PPC EEG attenuated the oscillatory bursts, indicating that olfactory gamma oscillations (20-80 Hz) were not phase-locked to the times of stimulus delivery but instead to inhalations. Time ensemble averages of neocortical recordings across trials revealed average evoked potentials starting 30-50 ms after the arrival of the stimulus.4. Average temporal fast Fourier transform (FFT) power spectral densities (PSDs) from pre- and poststimulus PPC EEG segments revealed a peak of gamma activity in olfactory bursts.5. The logarithm of the average temporal FFT PSDs from pre- and poststimulus neocortical EEG segments, when plotted against log frequency, revealed 1/f-type spectra in both pre- and poststimulus segments for negative/aversive conditioned stimuli (CS-) and positive/rewarding conditioned stimuli (CS+). The alpha'- and beta'-coefficients from the regression of Eq. 2 onto the average PSDs were significantly different between pre- and poststimulus segments, owing to the evoked potentials, but not between CS- and CS+ stimulus segments.6. Spatiotemporal patterns were invariant over all frequency bins in the 1/f domain (20-100 Hz). Spatiotemporal patterns in the 2- to 20-Hz domain progressively differed from the invariant patterns with decreasing frequency.7. In the spatial frequency domain, the logarithm of the average spatial FFT power spectra from pre- and poststimulus neocortical EEG segments, when plotted against the log spatial frequency, fell monotonically from the maximum at the lowest spatial frequency, downwardly curving to a linear 1/f spectral domain. This curve in the 1/f spectral domain extended from 0.133 to 0.880 cycles/mm in the PPC and from 0.095 to 0.624 cycles/mm in the neocortices.8. Methods of FFT and principal component analysis (PCA) EEG decomposition were used to extract the broad-spectrum waveform common to all 64 EEGs from an array. AM patterns for the FFT and PCA components were derived by regression. They were shown by cross-correlation to yield spatial patterns that were equivalent to each other and to AM patterns from calculation of the 64 root-mean-square amplitudes of the segments.9. Each spatial AM pattern was expressed by a 1 x 64 column vector and a point in 64-space. Similar patterns formed clusters, and dissimilar patterns gave multiple clusters. A statistical test was devised to evaluate dissimilarity by a Euclidean distance metric in 64-space.10. Significant spatial pattern classification of CS- versus CS+ trials (below the 1% confidence limit for 20 of each) was found in discrete temporal segments of poststimulus data after digital temporal and spatial filter optimization.11. Varying the analysis window duration from 10 to 500 ms yielded a window length of 120 ms as optimal for pattern classification. A 120-ms window was subsequently stepped across each record in overlapping intervals of 20 ms. Windows in which episodic, significant CS+/CS- differences occurred lasted 50-200 ms and were separated by 100-200 ms in the poststimulus period.12. Neocortical spatial patterns changed under reinforcement contingency reversal, showing a lack of invariance in respect to stimuli and a dependence on context and learning, as previously found for the olfactory bulb and PPC.13. The EEG data contributing to classification were homogeneously distributed across wide temporal and spatial spectral bands and across the spatial array of electrodes. Patterns could be resolved with as few as 16 channels. No channel was more or less contributory to classification than any other.14. The aperiodic waveforms, the rapid global state changes, the context dependence of the AM patterns, and the homogeneous distribution of neural activity suggest that the neural events formed during perception are constructed by cooperative population dynamics in both paleocortex and neocortex. These characteristics so far provide the most powerful evidence for spatially coherent, aperiodic oscillations manifesting macroscopic cortical states that are spatially continuous over areas >5 mm diam and that last