Biomaterial Database

Responses during eye movements of brain stem neurons that receive monosynaptic inhibition from the flocculus and ventral paraflocculus in monkeys. 1994

S G Lisberger, and T A Pavelko, and D M Broussard

Department of Physiology, W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco 94143.

1. We have identified a group of brain stem cells called "flocculus target neurons" (or FTNs) because they are inhibited at monosynaptic latencies by stimulation of the flocculus and the ventral paraflocculus with single electrical pulses. We report the responses of FTNs, as well as those of other brain stem cells, during horizontal eye movements with the head stationary and during natural vestibular stimulation in monkeys. 2. FTNs discharged primarily in relation to eye movements. The majority (71%) showed increased firing for eye movement away from the side of the recording ("contraversive"), which is consistent with their inhibition by Purkinje cells that show increased firing for eye movement toward the side of recording. However, a significant and surprisingly large percentage (29%) of FTNs showed increased firing for eye movement toward the side of recording ("ipsiversive"). 3. The firing rate of FTNs showed strong modulation during pursuit of sinusoidal target motion with the head stationary and during the compensatory eye movements evoked by fixation of an earth-stationary target with sinusoidal head rotation. In addition, firing rate was related to eye position during steady fixation at different positions. Of the FTNs that showed increased firing for contraversive eye motion during pursuit with the head stationary, most had an infection in the relationship between firing rate and eye position so that the sensitivity to eye position was low for eye positions ipsilateral to straight-ahead gaze and high for eye positions contralateral to straight-ahead gaze. 4. When the monkey canceled the vestibuloocular reflex (VOR) by tracking a target that moved exactly with him during sinusoidal head rotation, the firing rate of FTNs was modulated much less strongly than during pursuit with the head stationary. In the FTNs that showed increased firing for contraversive eye motion during pursuit, firing rate during cancellation of the VOR increased for contraversive head motion during sinusoidal vestibular rotation at 0.4 Hz but was only weakly modulated during rotation at 0.2 Hz. 5. The position-vestibular-pause cells (PVP-cells), previously identified as interneurons in the disynaptic VOR pathways, were not inhibited by stimulation of the flocculus and ventral paraflocculus and had response properties that were different from FTNs. The majority (69%) showed increased firing for contraversive eye motion during pursuit and for ipsiversive head motion during cancellation of the VOR, whereas some (31%) showed the opposite direction preferences under both conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007395	Interneurons	Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.	Intercalated Neurons,Intercalated Neuron,Interneuron,Neuron, Intercalated,Neurons, Intercalated
D008253	Macaca mulatta	A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.	Chinese Rhesus Macaques,Macaca mulatta lasiota,Monkey, Rhesus,Rhesus Monkey,Rhesus Macaque,Chinese Rhesus Macaque,Macaca mulatta lasiotas,Macaque, Rhesus,Rhesus Macaque, Chinese,Rhesus Macaques,Rhesus Macaques, Chinese,Rhesus Monkeys
D008297	Male		Males
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009949	Orientation	Awareness of oneself in relation to time, place and person.	Cognitive Orientation,Mental Orientation,Psychological Orientation,Cognitive Orientations,Mental Orientations,Orientation, Cognitive,Orientation, Mental,Orientation, Psychological,Orientations,Orientations, Cognitive,Orientations, Mental,Orientations, Psychological,Psychological Orientations
D011689	Purkinje Cells	The output neurons of the cerebellar cortex.	Purkinje Cell,Purkinje Neuron,Purkyne Cell,Cell, Purkinje,Cell, Purkyne,Cells, Purkinje,Cells, Purkyne,Neuron, Purkinje,Neurons, Purkinje,Purkinje Neurons,Purkyne Cells
D011698	Pursuit, Smooth	Eye movements that are slow, continuous, and conjugate and occur when a fixed object is moved slowly.	Pursuits, Smooth,Smooth Pursuit,Smooth Pursuits