Reese W G, Newton J E, Angel C
J Nerv Ment Dis. 1982 Oct;170(10):605-13. doi: 10.1097/00005053-198210000-00004.
Pointer dogs learn complex hunting tasks such as vigorous aim-directed activity in tracking specific birds and sudden rigid immobility "on point" at appropriate distance from the prey. In the presence of a human, dogs of the Arkansas Line of Nervous Pointers show markedly reduced activity. In close quarters, where they cannot flee, they usually react to humans by freezing. These responses do not extinguish. The breed demonstrates a strong capacity to inhibit motion. In our nervous dogs, this trait is greatly exaggerated. In the search for an objective and rapidly modifiable target motor sign to correlate with biochemical and pharmacological events, we discovered that 10 of 10 nervous dogs, in contrast to kennel mates of a normal line, developed tonic immobility (TI) which was induced by manual inversion into a sling and stroking. This is the first systematic demonstration of TI in mature dogs. The TI was accompanied by reduced telemetered heart rate (HR) compared to baseline. Release from the inverted position was accompanied by marked HR increase. In the absence of humans, both before and after the inversion, all nervous dogs showed little or no movement about the testing area. This was in contrast to the nine normal line dogs, which were comparable in age and sex. These normal dogs were very active before and after inversion into the sling. Five of the normals remained in the sling but did not show head and neck immobility and were generally relaxed. Their HRs increased slightly while in the inverted position, thereafter returning to baseline. The four normals which righted themselves soon after the inversion showed reduced HR with the resumed activity. We discuss possible mechanisms and review some of the implications for psychiatry and behavioral biology.
指示犬能够学会复杂的狩猎任务，比如在追踪特定鸟类时进行精力充沛的定向活动，以及在与猎物保持适当距离时突然僵硬不动地“站住”。在有人类在场的情况下，阿肯色神经指示犬系的犬只活动明显减少。在狭小空间里，它们无法逃脱时，通常会通过静止不动来对人类做出反应。这些反应不会消失。该犬种表现出很强的抑制运动的能力。在我们的神经指示犬中，这种特性被极大地夸大了。在寻找一个客观且可快速改变的目标运动信号以与生化和药理事件相关联的过程中，我们发现，与正常犬系的同窝犬相比，10只神经指示犬中有10只在被手动翻转到吊床并抚摸后出现了强直性静止（TI）。这是首次在成年犬中对TI进行系统的证明。与基线相比，TI伴随着遥测心率（HR）的降低。从倒置位置松开时，心率会显著增加。在没有人类的情况下，无论是在翻转之前还是之后，所有神经指示犬在测试区域内几乎没有或根本没有移动。这与9只年龄和性别相当的正常犬系犬不同。这些正常犬在被翻转到吊床前后都非常活跃。其中5只正常犬留在吊床上，但没有出现头部和颈部静止不动的情况，并且总体上比较放松。它们在倒置位置时心率略有增加，之后恢复到基线水平。另外4只在翻转后很快自行恢复正常姿势的正常犬在恢复活动时心率降低。我们讨论了可能的机制，并回顾了对精神病学和行为生物学的一些影响。
