scholarly journals A mechanism for eye position effects on spontaneous nystagmus

2012 ◽  
Author(s):  
E. Khojasteh ◽  
C. J. Bockisch ◽  
D. Straumann ◽  
S. C. A. Hegemann
Keyword(s):  
Spontaneous Nystagmus ◽  
Eye Position ◽  
Position Effects

Eye position effects in saccadic adaptation in macaque monkeys

2012 ◽  
Vol 108 (10) ◽  
pp. 2819-2826 ◽  
Author(s):  
Svenja Wulff ◽  
Annalisa Bosco ◽  
Katharina Havermann ◽  
Giacomo Placenti ◽  
Patrizia Fattori ◽  
...  
Keyword(s):  
Macaca Fascicularis ◽  
Species Differences ◽  
The Other ◽  
Eye Position ◽  
Saccadic Amplitude ◽  
Position Effects ◽  
Starting Position ◽  
Saccadic Adaptation ◽  
Gaussian Profile ◽  
Position Dependence

The saccadic amplitude of humans and monkeys can be adapted using intrasaccadic target steps in the McLaughlin paradigm. It is generally believed that, as a result of a purely retinal reference frame, after adaptation of a saccade of a certain amplitude and direction, saccades of the same amplitude and direction are all adapted to the same extent, independently from the initial eye position. However, recent studies in humans have put the pure retinal coding in doubt by revealing that the initial eye position has an effect on the transfer of adaptation to saccades of different starting points. Since humans and monkeys show some species differences in adaptation, we tested the eye position dependence in monkeys. Two trained Macaca fascicularis performed reactive rightward saccades from five equally horizontally distributed starting positions. All saccades were made to targets with the same retinotopic motor vector. In each session, the saccades that started at one particular initial eye position, the adaptation position, were adapted to shorter amplitude, and the adaptation of the saccades starting at the other four positions was measured. The results show that saccades that started at the other positions were less adapted than saccades that started at the adaptation position. With increasing distance between the starting position of the test saccade and the adaptation position, the amplitude change of the test saccades decreased with a Gaussian profile. We conclude that gain-decreasing saccadic adaptation in macaques is specific to the initial eye position at which the adaptation has been induced.

Eye Position Effects on the Neuronal Activity of Dorsal Premotor Cortex in the Macaque Monkey

1998 ◽  
Vol 80 (3) ◽  
pp. 1132-1150 ◽  
Author(s):  
Driss Boussaoud ◽  
Christophe Jouffrais ◽  
Frank Bremmer
Keyword(s):  
Reference Frame ◽  
Neuronal Activity ◽  
Premotor Cortex ◽  
Macaque Monkey ◽  
Limb Movement ◽  
Movement Direction ◽  
Eye Position ◽  
Dorsal Premotor Cortex ◽  
Position Effects ◽  
The Brain

Boussaoud, Driss, Christophe Jouffrais, and Frank Bremmer. Eye position effects on the neuronal activity of dorsal premotor cortex in the macaque monkey. J. Neurophysiol. 80: 1132–1150, 1998. Visual inputs to the brain are mapped in a retinocentric reference frame, but the motor system plans movements in a body-centered frame. This basic observation implies that the brain must transform target coordinates from one reference frame to another. Physiological studies revealed that the posterior parietal cortex may contribute a large part of such a transformation, but the question remains as to whether the premotor areas receive visual information, from the parietal cortex, readily coded in body-centered coordinates. To answer this question, we studied dorsal premotor cortex (PMd) neurons in two monkeys while they performed a conditional visuomotor task and maintained fixation at different gaze angles. Visual stimuli were presented on a video monitor, and the monkeys made limb movements on a panel of three touch pads located at the bottom of the monitor. A trial begins when the monkey puts its hand on the central pad. Then, later in the trial, a colored cue instructed a limb movement to the left touch pad if red or to the right one if green. The cues lasted for a variable delay, the instructed delay period, and their offset served as the go signal. The fixation spot was presented at the center of the screen or at one of four peripheral locations. Because the monkey's head was restrained, peripheral fixations caused a deviation of the eyes within the orbit, but for each fixation angle, the instructional cue was presented at nine locations with constant retinocentric coordinates. After the presentation of the instructional cue, 133 PMd cells displayed a phasic discharge (signal-related activity), 157 were tonically active during the instructed delay period (set-related or preparatory activity), and 104 were active after the go signal in relation to movement (movement-related activity). A large proportion of cells showed variations of the discharge rate in relation to limb movement direction, but only modest proportions were sensitive to the cue's location (signal, 43%; set, 34%; movement, 29%). More importantly, the activity of most neurons (signal, 74%; set, 79%; movement, 79%) varied significantly (analysis of variance, P < 0.05) with orbital eye position. A regression analysis showed that the neuronal activity varied linearly with eye position along the horizontal and vertical axes and can be approximated by a two-dimensional regression plane. These data provide evidence that eye position signals modulate the neuronal activity beyond sensory areas, including those involved in visually guided reaching limb movements. Further, they show that neuronal activity related to movement preparation and execution combines at least two directional parameters: arm movement direction and gaze direction in space. It is suggested that a substantial population of PMd cells codes limb movement direction in a head-centered reference frame.

Timing and Laminar Profile of Eye-Position Effects on Auditory Responses in Primate Auditory Cortex

2004 ◽  
Vol 92 (6) ◽  
pp. 3522-3531 ◽  
Author(s):  
Kai-Ming G. Fu ◽  
Ankoor S. Shah ◽  
Monica N. O'Connell ◽  
Tammy McGinnis ◽  
Haftan Eckholdt ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Linear Array ◽  
Current Source ◽  
Eye Position ◽  
Auditory Pathways ◽  
Position Effects ◽  
Auditory Responses ◽  
Cortical Responses ◽  
Auditory Response ◽  
Laminar Current

We examined effects of eye position on auditory cortical responses in macaques. Laminar current-source density (CSD) and multiunit activity (MUA) profiles were sampled with linear array multielectrodes. Eye position significantly modulated auditory-evoked CSD amplitude in 24/29 penetrations (83%), across A1 and belt regions; 4/24 cases also showed significant MUA AM. Eye-position effects occurred mainly in the supragranular laminae and lagged the co-located auditory response by, on average, 38 ms. Effects in A1 and belt regions were indistinguishable in amplitude, laminar profile, and latency. The timing and laminar profile of the eye-position effects suggest that they are not combined with auditory signals at a subcortical stage of the lemniscal auditory pathways and simply “fed-forward” into cortex. Rather, these effects may be conveyed to auditory cortex by feedback projections from parietal or frontal cortices, or alternatively, they may be conveyed by nonclassical feedforward projections through auditory koniocellular (calbindin positive) neurons.

Paroxysmal spontaneous nystagmus and vertigo evoked by lateral eye position

Neurology ◽  
1987 ◽  
Vol 37 (9) ◽  
pp. 1553-1553 ◽  
Author(s):  
U. Buttner ◽  
A. Straube ◽  
Th. Brandt
Keyword(s):  
Spontaneous Nystagmus ◽  
Eye Position ◽  
Lateral Eye

Eye position effects in saccadic adaptation

2011 ◽  
Vol 106 (5) ◽  
pp. 2536-2545 ◽  
Author(s):  
Katharina Havermann ◽  
Eckart Zimmermann ◽  
Markus Lappe
Keyword(s):  
Eye Movements ◽  
Visual Space ◽  
Initial Position ◽  
Head Movements ◽  
Eye Position ◽  
Saccade Amplitude ◽  
Position Effects ◽  
Position Information ◽  
Saccadic Adaptation ◽  
Visual Error

Saccades are used by the visual system to explore visual space with the high accuracy of the fovea. The visual error after the saccade is used to adapt the control of subsequent eye movements of the same amplitude and direction in order to keep saccades accurate. Saccadic adaptation is thus specific to saccade amplitude and direction. In the present study we show that saccadic adaptation is also specific to the initial position of the eye in the orbit. This is useful, because saccades are normally accompanied by head movements and the control of combined head and eye movements depends on eye position. Many parts of the saccadic system contain eye position information. Using the intrasaccadic target step paradigm, we adaptively reduced the amplitude of reactive saccades to a suddenly appearing target at a selective position of the eyes in the orbitae and tested the resulting amplitude changes for the same saccade vector at other starting positions. For central adaptation positions the saccade amplitude reduction transferred completely to eccentric starting positions. However, for adaptation at eccentric starting positions, there was a reduced transfer to saccades from central starting positions or from eccentric starting positions in the opposite hemifield. Thus eye position information modifies the transfer of saccadic amplitude changes in the adaptation of reactive saccades. A gain field mechanism may explain the eye position dependence found.

scholarly journals Eye position effects in macaque area V4

Neuroreport ◽  
2000 ◽  
Vol 11 (6) ◽  
pp. 1277-1283 ◽  
Author(s):  
Frank Bremmer
Keyword(s):  
Eye Position ◽  
Position Effects ◽  
Area V4
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