Control mechanisms of orienting movements of the head in the vertical direction.

Forel’s field H （FFH）位于中间脑连接区，红核的背侧。几乎所有FFH神经元都投射到桥髓网状结构，其中约一半进一步投射到上颈髓。FFH神经元通过脑桥和髓质的网状脊髓神经元单突触和双突触作用于背颈运动神经元。这种效果几乎只对头部升降肌（双颈肌和复合体）有影响。猫被训练做定向动作。他们站在一个圆周的前面，圆周上水平排列着7个发光二极管（led），垂直排列着12个led。当猫盯着一个已经打开的中心LED时，把头转过去，盯着一个在关闭中心LED后立即打开的新外围LED时，它们会从LED下面打开的一个小洞里得到一个小小的平静。头部在垂直方向上的定向运动由三个部分组成。在颈部和躯干关节处头部旋转的颈部旋转，在寰枕关节处头部旋转的头部旋转。平行移动，主要通过前肢的运动来平行地抬起或放下头部头部运动的角速度与头部运动的总振幅呈线性关系。双侧向FFH内注射kainic酸后，颈部和躯干肌肉的紧张性活动在10 ~ 20小时内急剧增加，在70小时左右下降后恢复。猫可以将头部和眼睛指向水平方向的led，但不能指向垂直方向。猫逐渐设法在垂直方向上进行定向运动，主要是通过平行移动。这些结果表明FFH是控制头部垂直运动的前运动中心。

Forel's field H (FFH) is located in the mesodiencephalic junctional area, rostrodorsal to the red nucleus. Almost all FFH neurons projected to the pontomedullary reticular formation and about half of them further to upper cervical cord. FFH neurons exert excitatory effects on dorsal neck motoneurones both monosynaptically and disynaptically through reticulospinal neurons in the pons and medulla. The effects were almost exclusively to head elevator muscles (biventer cervicis and complexus). Cats were trained to make orienting movements. They stand in front of a perimeter on which 7 light emitting diodes (LEDS) were arrange horizontally and 12 LEDs vertically. When cats, fixating a center LED which had been turned on, direct heads and fixate a new peripheral LED which turned on immediately after switching off the center LED, they were rewarded with a small peace of meet from a small hole opened beneath the LED. Orienting movements of the head in the vertical direction were consist of three components. Neck rotation in which head rotated at neck and trunk joint, head rotation in which heads rotated at the atlanto-occipital joint. Parallel shifts in which the head was lifted or lowered parallelly mainly by forelimb movements.Angular velocity of head movements related linearly to the total amplitudes of head movements. Following bilateral injection of kainic acid into FFH, tonic activity of neck and trunk muscles, increased dramatically for 10-20 hours, decreased for about 70 hours and then recovered.Cats could direct head and eyes to LEDs in the horizontal direction but not in the vertical direction. Cats gradually managed to make orienting movements in vertical direction mainly by parallel shifts. These results suggested that FFH is a premotor center controlling vertical head movements.