Miliaressis E, Rompré P P
School of Psychology, University of Ottawa, Canada.
Behav Neurosci. 1987 Dec;101(6):827-31. doi: 10.1037//0735-7044.101.6.827.
In self-stimulation behavior, the rate-frequency (R-F) function relates bar-pressing performance to the number of cathodal pulses of constant intensity, delivered in a train of fixed duration. The lateral position of the R-F function depends on the rewarding efficacy of the stimulation; a shift of the function toward larger pulse numbers after some experimental manipulation indicates a decrease in the efficacy of the stimulation. Because self-stimulation is often accompanied by stimulation-contingent motoric reactions, it is required to show that such reactions do not alter the estimates of rewarding efficacy of the stimulation. We describe an experiment in which the presence and severity of motoric reactions were controlled experimentally by simultaneous stimulation through a second electrode, located in a motoric brain region. Rats were implanted with one hypothalamic (LH) electrode (which elicited self-stimulation) and one reticular (RF) electrode (which elicited head and body movements). The rate-frequency function for each LH electrode was obtained under a single-pulse condition (LH electrode alone) and under a paired-pulse condition repeated three times, in which each LH pulse was accompanied by three different intensities of an RF pulse. Despite its severe effect on the slope and the asymptotic rate of R-F function, the interfering reaction failed to shift the R-F function to any significant degree. We concluded that these interfering reactions do not alter the estimates of neuronal density obtained through application of the curve-shift paradigm.
在自我刺激行为中，速率-频率（R-F）函数将压杆行为与在固定持续时间的一串脉冲中施加的恒定强度的阴极脉冲数量联系起来。R-F函数的横向位置取决于刺激的奖赏效力；在经过一些实验操作后，函数向更大脉冲数的方向移动表明刺激效力降低。由于自我刺激通常伴随着与刺激相关的运动反应，因此需要证明此类反应不会改变对刺激奖赏效力的估计。我们描述了一项实验，其中通过位于运动脑区的第二个电极同时进行刺激，对运动反应的存在和严重程度进行了实验控制。给大鼠植入一个下丘脑（LH）电极（可引发自我刺激）和一个网状结构（RF）电极（可引发头部和身体运动）。在单脉冲条件下（仅使用LH电极）以及重复三次的双脉冲条件下，获得每个LH电极的速率-频率函数，在双脉冲条件下，每个LH脉冲都伴随着三种不同强度的RF脉冲。尽管干扰反应对R-F函数的斜率和渐近速率有严重影响，但它并未使R-F函数发生任何显著的移动。我们得出结论，这些干扰反应不会改变通过应用曲线移动范式获得的神经元密度估计值。
