Temporal selectivity of identified auditory neurons in the cricket brain
Temporal selectivity of identified auditory neurons in the cricket brain
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蟋蟀大脑中已识别听觉神经元的时间选择性
DOI：
10.1007/bf00612635
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
K. Schildberger
中科院分区：
文献类型：
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作者：
K. Schildberger
1.用荧光黄标记的方法，用细胞内记录法研究了蟋蟀脑内58个神经元对听觉刺激的反应。这些听觉中间神经元可以根据解剖学标准分为三类：（一）神经元（AN 1和AN 2）从胸前神经节上升到大脑，（ii）大脑神经元（BNC 1）与那些上升细胞重叠的分支，和（iii）脑神经元（BNC 2）所有上行神经元都有一个共同的投射野，位于弥漫性神经节的前背侧区域，位于脑叶的外侧。该区域与BNC 1神经元的投影区域重叠。BNC 1神经元的其他投射区经常出现在后腹区，在原脑和中脑之间的边界处;后者与BNC 2细胞的投射区重叠，其分支通常不清楚地分布在一个以上的不同区域（图2和3）。1-4).3.阈值曲线和阈上反应显示，所有三类（AN，BNC 1和BNC 2）包括低频（5 kHz）和宽带（2-20 kHz）调谐的细胞;高频（10-20 kHz）调谐仅见于AN和BNC 1细胞。在细胞被调谐到的区域内，灵敏度按AN、BNC 1、BNC 2的顺序降低（图1A和1B）。第2-4段）。一个经常观察到的属性的BNC 2神经元是独立的声音强度在阈上强度区域。反应潜伏期按AN、BNC 1、BNC 2的顺序增加（图1A和1B）。4.通过呈现“恒定能量啁啾”，即持续时间和重复间隔不同的声脉冲（音节）序列，研究了刺激时间结构的影响。低频AN 1神经元，像其他前胸神经元一样，在广泛的重复间隔内复制这些信号。BNC 1神经元的反应不太准确，而BNC 2神经元的反应通常与刺激的音节不同步（图1A和1B）。5.引人注目的是，在某些情况下（15个中的7个）发现BNC 2反应的幅度随重复间隔而变化; BNC 2反应对重复间隔的曲线与给定相同刺激范例的女性的行为跟踪反应的曲线紧密匹配，并且在高于阈值10 dB或更高的强度下与强度无关。与此相反，AN和大多数BNC 1神经元的反应是一致的，无论刺激强度如何，在整个研究的重复间隔范围内（图11）。6.一些BNC 2神经元对恒定能量啁啾的反应只有短和中间或中间和长的重复间隔，类似于青蛙中发现的高通和低通神经元（图12）。这一发现，系统的潜伏期差异，以及AN，BNC 1和BNC 2细胞之间的解剖关系，都指向了一个相当具体的男性呼叫歌曲识别方式的图片。
Summary1.The responses of fifty-eight neurons in the cricket brain to auditory stimuli were studied by intracellular recording, after which the cells were marked with Lucifer Yellow. These auditory interneurons could be assigned to three classes on the basis of anatomical criteria: (i) neurons (AN1 and AN2) ascending from the prothoracic ganglion into the brain, (ii) brain neurons (BNC 1) with arborizations overlapping those of ascending cells, and (iii) brain neurons (BNC 2) with arborizations that had no overlap with those of ascending cells.2.All the ascending neurons had one projection field in common, an area in the anterior dorsal region of the diffuse neuropil lateral to the alphalobe. This field overlaps one of the projection fields of the BNC 1 neurons. Other projection fields of the BNC 1 neurons are frequently found in the posterior ventral region, at the boundary between the proto and deutocerebrum; the latter overlap projection fields of the BNC 2 cells, the arborizations of which are often not clearly distributed in more than one distinct region (Figs. 1–4).3.The threshold curves and suprathreshold responses revealed that all three classes (AN, BNC 1 and BNC 2) include cells with low frequency (5 kHz) and others with broad-band (2–20 kHz) tuning; high-frequency (10–20 kHz) tuning was found only in AN and BNC 1 cells. Within the region to which the cells were tuned, sensitivity decreased in the order AN, BNC 1, BNC 2 (Figs. 2–4). A frequently observed property of BNC 2 neurons was independence of sound intensity in the suprathreshold intensity region. The response latency increased in the order AN, BNC 1, BNC 2 (Figs. 5, 6).4.The effect of stimulus temporal structure was studied by presenting ‘constant-energy-chirps’, trains of sound pulses (syllables) varying in duration and repetition interval. The low frequency AN1 neurons, like other prothoracic neurons, copy such signals over a broad range of repetition intervals. Copying by the BNC 1 neurons was less accurate, and the responses of BNC 2 neurons were often not detectably synchronized with the syllables of the stimuli (Figs. 7–10).5.Strikingly, the magnitude of the BNC 2 responses was in some cases (7 out of 15) found to vary with repetition interval; curves for the BNC 2 responses vs. repetition interval match closely those for the behavioral tracking response of females given an identical stimulus paradigm, and are independent of intensity at intensities 10 dB or more above threshold. By contrast, the responses of AN and most BNC 1 neurons are uniform, regardless of stimulus intensity, over the entire range of repetition intervals studied (Fig. 11).6.Some BNC 2 neurons responded to constantenergy chirps only with short and intermediate or with intermediate and long repetition intervals, resembling the high-pass and low-pass neurons found in frogs (Fig. 12). This finding, the systematic latency differences, and the anatomical relationships among the AN, BNC 1 and BNC 2 cells all point to a rather specific picture of the way that the male calling song is recognized.