Ch 18: Pursuit Flashcards
purpose of pursuit eye movements
to hold gaze on relatively slow-moving objects that are moving laterally (up, down or sideways) in the environment
in schor’s classification system, pursuit eye movements have a
gaze-lock function
what is one thing pursuit and optokinetic eye movements can help with and why
they both help to reduce motion blur that would otherwise occur if the retinal image moved too quickly
smooth vergence and pursuit differences
smooth vergence is disconjugate eye movement, pursuit is conjugate
when are smooth vergence and pursuit used together?
if the object moves laterally and in depth at the same time
saccades relationship with pursuit
usually before pursuit can lock the gaze on a moving object, a saccade has to occur to place the gaze on the object initially
how does the pursuit system use visual stimuli
it matches eye velocity to perceived target velocity
what non-visual stimuli can elicit pursuit
auditory stimuli can help pursue more accurately
pursuits demonstrate dual-mode behavior, what is this?
following, or slow phase generated by neg. feedback tracking system and catch up saccades by independent mechanism to correct position errors
information from the retina passes through the ___ to ___
lateral geniculate nucleus (LGN) to visual cortex (V1)
-magnocellular pathways are more important to pursuit
MT area
receives motor information from visual cortex, speed and direction of moving objects
MST area
receives projections from MT neurons- code for different aspects of motion, not all useful to pursuit
what is important about frontal eye field (FEF) and supplementary eye field (SEF) areas for pursuit?
these areas are involved in the predictive aspects of smooth pursuit
where does the DLPN receive info from and where does it project?
receives signals from MST, FEF, and SEF
-contains projections to cerebellar areas
what cerebellar area is most associated with smooth pursuit of a constant velocity object?
paraflocculus
