1. Physiology and Psychophysics of Eye Movements 1.Muscles and (cranial) nerves 2. Classes of eye movements/oculomotor behaviors 3. Saccadic Eye Movements, metrics and factoids 4. Brainstem control of saccadic eye movements 5. Superior Colliculus and cortical control of saccades 6. Saccades and Visual Perception

2. Extraocular Muscles: three complimentary pair

3. Measuring Eye Movements/Position Scleral search coil older methods: electro-oculogram (EOG), coil contacts, suction caps of Yarbus Infrared Eye Tracking Temporal resolution: analog Spatial resolution: <0.1 deg. Temporal resolution: video frame rate, <500 Hz Spatial resolution: <0.25 deg. scleral coil magnetic field (2 axes)

4. Adapted from Yarbus (1967)

5. Classes of Eye Movements 1.Vestibulo-Ocular (VOR): Hold images of the seen world steady on the retina during brief head movements (angular or translational). -very short latency (<15 ms) because signal is from inner ear. 2. Visual Fixation: Holds image of a stationary image on the fovea 3. Optokinetic: Hold images of the seen world steady on the retina during prolonged head movements. 4. Smooth pursuit: Holds the image of a small (moving) target on the fovea. -cannot move gaze smoothly without stimulus 5. Vergence: Moves the eyes in opposite directions so that images of a single object are placed or held simultaneously on both foveas. -2 signals: disparity, accommodative 6. Saccadic Eye Movements: Bring objects of interest onto fovea

6. Combinations of eye movement types. Optokinetic Nystagmus (OKN): Slow phase-optokinetic Quick phase-saccadic time Saccades and pursuit: Pursuit pre- and post- saccadic Without saccade With saccade Left eye Vergence Angle Right eye Saccades and vergence: Vergence with a saccade is much faster

8. Saccadic Eye Movements (‘saccades’) Subtypes often referred to: 1. Volitional (‘purposive’) -predictive, anticipatory -memory-guided -antisaccades 2. Reflexive 3. Express saccades 4. Spontaneous 5. Quick phase of nystagmus

9. Velocity, Duration and the ‘Main Sequence’ Visually Guided Saccades Deviations from main sequence: -saccades in complete darkness -saccades to auditory stimuli -saccades to remembered targets -saccades made in the opposite direction (antisaccades)

12. [abducens, trochlear, om nucleus] [cerebellum, brainstem] [pprf, mrf] [dorsal raphe]

13. Major Pathways for Saccadic Eye Movements in the Monkey

16. Sparks and Mays, 1980 Tuning of SC burst neuron to direction and amplitude of saccades

17. ‘Movement field’ of Superior Colliculus neuron

18. Map of Stimulation Evoked Saccades amplitude elevation Rostral Caudal

20. Enhancement of Superior Colliculus Visual Responses and the Need to Dissociate Behavioral Components Passive fixation Saccade to RF target Saccade to Control target

21. Superficial Layers Intermediate and Deep Layers Retina Major Connections of the Superior Colliculus Striate cortex (V1)Extrastriate cortex (e.g. V4, MT) Parietal cortex (e.g. LIP) Frontal Eye Field Inferior Pulvinar Brainstem Saccade generator Dorsal lateral geniculate nucleus (dLGN) Medio-dorsal thalamus SC

22. Tasks used to characterize saccade-related activity 1. step task (simultaneous, overlap, gap) fixation point saccade target eye position (h) time

23. Tasks used to characterize saccade-related activity 2. visually-guided, delayed saccade task fixation point saccade target eye position (h) time

24. Tasks used to characterize saccade-related activity 3. memory-guided, delayed saccade task fixation point saccade target eye position (h) time

25. Tasks used to characterize saccade-related activity 4. anti-saccade task fixation point saccade target eye position (h) time

26. Visual and Motor Related Properties of Cells in the Superior Colliculus Superficial Layers: Intermediate: Deep Layers SC Visual Receptive Fields, Some enhanced Visual Responses, but no Presaccadic (motor) bursts; ‘visual’ cells Visual Receptive Fields and Presaccadic Bursts before saccades to ‘movement field’; ‘visuomotor cells’, ‘visually-triggered motor cells’ No visual RFs, just movement fields, Presaccadic burst gets earlier as you go deeper

27. Major Pathways for Saccadic Eye Movements in the Monkey (FEF) (SEF) Lateral Intraparietal Area (LIP)

28. Continuum of Visual and Motor Responses in the FEF

29. Microstimulation of the Frontal Eye Field

30. Arcuate ant. post. Functional Organization of Macaque FEF

31. Stimulation-Evoked Smooth Pursuit Movements

32. Stimulation-Evoked Vergence Movements

33. Cortical Connections of the FEF: organized and reciprocal connections with ‘dorsal’ and ‘ventral’ visual pathways

34. Major Pathways for Saccadic Eye Movements in the Monkey (FEF) (SEF) Lateral Intraparietal Area (LIP)

35. Lateral Intraparietal Area (LIP): visual, saccade-related and mnemonic responses

36. Incidence of ‘light-sensitive’, ‘saccade-coincident’ and ‘memory’ activity in LIP

37. Microstimulation of Parietal Cortex: fixed and ‘modified’ vector saccades