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

Forel‘s field H(FFH)位于中间脑交界区，位于红核的背侧。几乎所有的FFH神经元都投射到脑桥延髓网状结构，其中约一半投射到上颈髓。FFH神经元通过桥脑和延髓的网状脊髓神经元对后颈运动神经元产生单突触和双突触的兴奋作用。这种影响几乎只对头部提升肌(颈二头肌和复合肌)起作用。猫被训练做定向动作。他们站在一个圆周的前面，在圆周上水平排列着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，引导头部并注视一个新的外围LED时，这个新的外围LED在关闭中心LED后立即打开，它们从LED下面打开的一个小洞里得到了一个小小的平静。头部在垂直方向上的定向运动由三个部分组成。颈部旋转是指头部在颈部和躯干关节旋转，头部旋转是指头部在寰枕关节旋转。平移，平移主要通过前肢运动使头部平行升降。头部运动的角度速度与头部运动的总幅度成线性关系。双侧FFH注射海人酸后，颈部和躯干肌肉的紧张性活动在10-20小时内急剧增加，70小时后下降，然后恢复。猫头和眼睛可以将头和眼睛指向水平方向的LED，而不是垂直方向的LED。猫主要通过平行移动，逐渐在垂直方向上进行定向运动。这些结果提示，FFH是控制头部垂直运动的运动前中枢。

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.