PMID- 10368380
OWN - NLM
STAT- MEDLINE
DCOM- 19990805
LR  - 20171213
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 81
IP  - 6
DP  - 1999 Jun
TI  - Neural organization from the superior colliculus to motoneurons in the horizontal 
      oculomotor system of the cat.
PG  - 2597-611
AB  - The neural organization of the superior colliculus (SC) projection to horizontal 
      ocular motoneurons was analyzed in anesthetized cats using intracellular 
      recording and transneuronal labeling. Intracellular responses to SC stimulation 
      were analyzed in lateral rectus (LR) and medial rectus (MR) motoneurons and 
      internuclear neurons in the abducens nucleus (AINs). LR motoneurons and AINs 
      received excitation from the contralateral SC and inhibition from the ipsilateral 
      SC. The shortest excitation (0.9-1.9 ms) and inhibition (1.4-2.4 ms) were mainly 
      disynaptic from the SC and were followed by tri- and polysynaptic responses 
      evoked with increasing stimuli or intensity. All MR motoneurons received 
      excitation from the ipsilateral SC, whereas none of them received any 
      short-latency inhibition from the contralateral SC, but some received excitation. 
      The latency of the ipsilateral excitation in MR motoneurons (1.7-2.8 ms) 
      suggested that this excitation was trisynaptic via contralateral AINs, because 
      conditioning SC stimulation spatially facilitated trisynaptic excitation from the 
      ipsilateral vestibular nerve. To locate interneurons mediating the disynaptic SC 
      inputs to LR motoneurons, last-order premotor neurons were labeled 
      transneuronally after injecting wheat germ agglutinin-conjugated horseradish 
      peroxidase into the abducens nerve, and tectoreticular axon terminals were 
      labeled after injecting dextran-biotin into the ipsilateral or contralateral SC 
      in the same preparations. Transneuronally labeled neurons were mainly distributed 
      ipsilaterally in the paramedian pontine reticular formation (PPRF) rostral to 
      retrogradely labeled LR motoneurons and the vestibular nuclei, and 
      contralaterally in the paramedian pontomedullary reticular formation (PPMRF) 
      caudomedial to the abducens nucleus and the vestibular nuclei. Among the 
      last-order premotor neuron areas, orthogradely labeled tectoreticular axon 
      terminals were observed only in the PPRF and the PPMRF contralateral to the 
      injected SC and seemed to make direct contacts with many of the labeled 
      last-order premotor neurons in the PPRF and the PPMRF. These morphological 
      results confirmed that the main excitatory and inhibitory connections from the SC 
      to LR motoneurons are disynaptic and that the PPRF neurons that receive 
      tectoreticular axon terminals from the contralateral SC terminate on ipsilateral 
      LR motoneurons, whereas the PPMRF neurons that receive tectoreticular axon 
      terminals from the contralateral SC terminate on contralateral LR motoneurons.
FAU - Izawa, Y
AU  - Izawa Y
AD  - Department of Physiology, School of Medicine, Tokyo Medical and Dental 
      University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113, Japan.
FAU - Sugiuchi, Y
AU  - Sugiuchi Y
FAU - Shinoda, Y
AU  - Shinoda Y
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
RN  - 0 (Molecular Probes)
RN  - 0 (Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate)
SB  - IM
MH  - Animals
MH  - Cats
MH  - Electric Stimulation
MH  - Excitatory Postsynaptic Potentials/physiology
MH  - Membrane Potentials/physiology
MH  - Microelectrodes
MH  - Molecular Probes
MH  - Motor Neurons/*physiology/ultrastructure
MH  - Neural Pathways/cytology/physiology/ultrastructure
MH  - Oculomotor Muscles/*innervation/ultrastructure
MH  - Superior Colliculi/cytology/*physiology/ultrastructure
MH  - Synapses/physiology/ultrastructure
MH  - Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
EDAT- 1999/06/16 00:00
MHDA- 1999/06/16 00:01
CRDT- 1999/06/16 00:00
PHST- 1999/06/16 00:00 [pubmed]
PHST- 1999/06/16 00:01 [medline]
PHST- 1999/06/16 00:00 [entrez]
AID - 10.1152/jn.1999.81.6.2597 [doi]
PST - ppublish
SO  - J Neurophysiol. 1999 Jun;81(6):2597-611. doi: 10.1152/jn.1999.81.6.2597.