SINGLE-UNIT SELECTIVITY TO AZIMUTHAL DIRECTION AND SOUND PRESSURE LEVEL OF NOISE BURSTS IN CAT HIGH-FREQUENCY PRIMARY AUDITORY-CORTEX
SINGLE-UNIT SELECTIVITY TO AZIMUTHAL DIRECTION AND SOUND PRESSURE LEVEL OF NOISE BURSTS IN CAT HIGH-FREQUENCY PRIMARY AUDITORY-CORTEX
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DOI：
10.1152/jn.1990.63.6.1448
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发表时间：
1990-06-01
影响因子：
2.5
通讯作者：
SAMSON, FR
中科院分区：
文献类型：
--
作者：
IMIG, TJ;IRONS, WA;SAMSON, FR
1.本文利用可移动扬声器在自由场中发出的宽带噪声脉冲，研究了巴比妥类麻醉猫初级听皮层单单位反应的方位角和声压级选择性。这些实验是在一个准消声隔音室中进行的。我们研究了71个相对稳定的响应特性的单位。所有装置均位于5.8和31 kHz之间的频率表示中。将每个单元获得的数据显示为方位水平响应区域，即显示响应幅度分布的等高线图，该分布是0度仰角处SPL和方位角的联合函数。从这些，方位角和水平的功能，获得方位角和水平的选择性的描述符。2.从每个单元的平均方位角函数的调制（针对所呈现的噪声的每个SPL获得的方位角函数的平均值）评估对声源方位角的灵敏度。样本被任意分为高方向性（HD）组（66%）和低方向性（LD）组（34%），高方向性（HD）组的平均方位角函数具有大于或等于75%的调制值。HD和LD组之间的区别，以便我们可以分析的特点，可能涉及的声源方位角的表示单位。3.在HD单元的样本中，对侧声场和中线的代表性过高。每个单元的首选扇区定义为正面声场内的方位角范围，在该范围内，单元响应大于或等于最大值的75%。每个单位被分类为中线偏好（17%，首选部门的中点，即，最佳方位，位于中线5度以内），对侧偏好（60%），或同侧偏好（23%）。对侧与同侧偏好单位的比例为2.5：1。更高比例的单元具有位于以中线为中心的10度扇区中的最佳方位角，而不是位于正面声场的任何其他10度扇区中。4.在一只动物中，录音获得在七个紧密间隔的网站在第四层从单和多单元的反应，这是狭隘的调整到方位角和SPL。位于沿着1 mm长的隔离带的单元被调谐到类似的频率和SPL，但具有分布在整个正面声场中的五个明显不同的方向偏好。（400字处截断摘要）
1. The azimuth and sound pressure level (SPL) selectivities of single-unit responses recorded in primary auditory cortex of barbiturate-anesthetized cats were studied by the use of broadband noise bursts delivered in the free field from a moveable loud-speaker. The experiments were carried out with cats located inside a quasianechoic sound-isolation chamber. We studied 71 units with relatively stable response properties. All units were located in the frequency representation between 5.8 and 31 kHz. The data obtained for each unit were displayed as an azimuth-level response area, a contour plot that displays the distribution of response magnitude as a joint function of SPL and azimuth at 0 degrees elevation. From these, azimuth and level functions were obtained to derive descriptors of azimuth and level selectivity. 2. Sensitivity to sound-source azimuth was assessed from the modulation of the average azimuth function (average of azimuth functions obtained to each SPL of noise that was presented) for each unit. The sample was arbitrarily divided into a high-directionality (HD) group (66%) whose average azimuth functions had modulation values of greater than or equal to 75% and a low-directionality (LD) group (34%). The distinction between HD and LD groups was made so that we could analyze the characteristics of units likely to be involved in the representation of sound-source azimuth. 3. There is an overrepresentation of the contralateral sound field and the midline in the sample of HD units. The preferred sector for each unit was defined as the range of azimuths within the frontal sound field throughout which unit response was greater than or equal to 75% of maximum. Each unit was classified as either midline preferring (17%, the midpoint of the preferred sector, i.e., best azimuth, was located within 5 degrees of the midline), contralateral preferring (60%), or ipsilateral preferring (23%). The ratio of contralateral- to ipsilateral-preferring units was 2.5:1. A higher proportion of units had best azimuths located in the 10 degrees sector centered on the midline than in any other 10 degrees sector of the frontal sound field. 4. In one animal, recordings were obtained at seven closely spaced sites in layer IV from single- and multiunit responses, which were narrowly tuned to both azimuth and SPL. The units located along a 1-mm length of an isofrequency strip were tuned to similar frequencies and SPLs but had five distinctly different directional preferences distributed throughout the entire frontal sound field.(ABSTRACT TRUNCATED AT 400 WORDS)