Vision in 1 Lecture Prof. Jack Pettigrew Vision Touch and Hearing Research Centre, University of Queensland 4072 Australia.

Vision: 1.Parallel Visual Pathways: Diversity of retinal ganglion cells and their destinations E.g. Melanopsin and the circadian clock system: SCN, jet lag etc 2. “Ventral” (conscious) vs. “dorsal” (unconscious) visual streams Blindsight: Veridical vs. Non-veridical

(Blind spot)

Melanopsin-containing light sensitive retinal ganglion cell M M MM M P P DS P LS

Parallel Visual Paths: >9 Separate Destinations of Retinal Ganglion Cells 1.SCN of hypothalamus…melanopsin system.CIRCADIAN CLOCK 2.dLGN (4 P & 2M layers)..geniculostriate. CONSCIOUS VISION ………ventral (&dorsal) stream OBJECT ID 3.Pulvinar-LP complex……MT…dorsal stream…..VISUOMOTOR 4.Pretectal complex…………….NEAR REFLEX TRIAD 5.Midbrain superior colliculus………VISUAL ORIENTATION 6.Accessory optic system…………….VISUAL STABILISATION Dorsal TN, lateral TN, medial TN (pitch, roll & yaw) 7. Habenula, raphe etc ……………..

III IV

III IV Forebrain Midbrain Hindbrain

Anterograde Transport of ocular label

1.SCN circadian clock Input from melanopsin ganglion cells 24 hr periodic expression of “Clock” genes Interhemispheric oscillator Characterised only in last decade

Labelling in Suprachiasmatic Nucleus (SCN): lac-Z-melanopsin construct

1. SCN circadian clock 2. dLGN geniculo-striate path Huge in primates Binocular vision emphasised: 3 layers for each eye Conscious vision Developmentally plastic V1 Striate cortex

1. SCN circadian clock 2. DLGN geniculostriate 3.Pulvinar-LP complex Old tectal system: primary system in most vertebrates Dominated by striate input in primates MT

1. SCN 2. dLGN 3.Pulvinar- LP complex 4. Pretectum Near triad, focus, miosis, vergence

1. SCN circadian clock 2. DLGN geniculostriate 3.Pulvinar- LP complex Old tectal system 5. Midbrain-Sup.Colliculus: orientation “visual grasp reflex” “hard wired: lateral visual field 4. Pretectum

1. SCN 2. dLGN 3.Pulvinar- LP complex 6. Accessory Optic DS ganglion cells Stabilisation Cerebellum Vestibular interaction 4. Pretectum 5. Midbrain- Sup. colliculus

1. SCN 2. dLGN 3.Pulvinar- LP complex 6. Accessory Optic 4. Pretectum 5. Midbrain- Sup. colliculus 7. Habenula, Raphe ?? Function Colour spectrum mood Visual input to “switch”

V1 P 1. SCN 2. dLGN 3.Pulvinar- LP complex 6. Accessory Optic 4. Pretectum 5. Midbrain- Sup. colliculus 7. Habenula, Raphe

V1 MT M M 1. SCN 2. dLGN 3.Pulvinar- LP complex 6. Accessory Optic 4. Pretectum 5. Midbrain- Sup. colliculus 7. Habenula, Raphe M M M

V1 MT DM P M M 2. dLGN 3.Pulvinar- LP complex 5. Midbrain- Sup. colliculus Dorsal Stream M M MM

V1 MT DM P M M 2. dLGN 3.Pulvinar- LP complex 5. Midbrain- Sup. colliculus Ventral Stream M M MM

V1 MT DM P M M 2. dLGN 3.Pulvinar- LP complex 5. Midbrain- Sup. colliculus Ventral Stream M M MM

V1 MT DM P M M 2. dLGN 3.Pulvinar- LP complex 5. Midbrain- Sup. colliculus Ventral Stream M M MM

V1 MT DM P M M Ventral Stream IT IT visual Cortex in temporal pole: Complex object recognition, including faces (FF area) Highly plastic (lesions here affect visual memory) Major output projection to limbic system, hippocampus

Hierarchical; V1 V2 etc IT Multiply interconnected “Apex” of hierarchy is hippocampal cortex Each has complete representation of visual field Functional specialisation (colour, motion,depth etc) Dorsal Stream V1, MT, DM, P Precision place “Where?” M system Unconscious Veridical No illusions V1 V2 MT V5 V3 Faces Places IT 26 DM S1 S2 etc P A1 Ventral Stream V1,V2,V3,…..IT Object identification “What?” P system Conscious Abstract Illusions Multiple visual cortical areas