8.垂直眼球運動の神経機構
垂直性バーストニューロンとその局在
1997 年 56 巻 5 号 p. 413-419
詳細
1997 年 56 巻 5 号 p. 413-419
A paramedian area of the mesodiencephalic junction, referred to as the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) or Forel's field H, is important in the genesis of vertical saccadic eye movements. Vertical medium-lead burst neuron (MLBN) exhibits a high frequency burst of spikes that are induced 5-15 msec prior to vertical saccades. These MLBNs are located in the dorsomedial part of the Forel's field H. These MLBNs directly project to the oculomotor nucleus, forming direct synaptic connections with vertical eye movement-related motoneurons in the oculomotor nucleus. Omnipause neurons (OPNs) in the paramedian pontine reticular formation form direct inhibitory connections with vertical MLBNs. Based on these results, we postulated that vertical saccades are generated when the disynaptic excitatory input from the superior colliculus reaches the vertical MLBNs, which form direct connections with vertical motoneurons. The high frequency spike burst of the MLBNs during vertical saccades is presumed to be created by this excitatory input when the MLBNs are released from tonic inhibition caused by OPN activity.
