Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to...
-
Upload
nicodemo-spada -
Category
Documents
-
view
216 -
download
0
Transcript of Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to...
![Page 1: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/1.jpg)
Visual processing in the retina
Receptive field of ganglion cells (in retina) selectively respond to different patterns of light.
On-centre cell“On” response when light falls on centre.“Off” response with light in periphery
Off-centre cell“Off” response when light falls on centre.“On” response with light in periphery
![Page 2: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/2.jpg)
![Page 3: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/3.jpg)
![Page 4: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/4.jpg)
![Page 5: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/5.jpg)
Il sistema visivo
![Page 6: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/6.jpg)
Vie Ottiche- Il nervo ottico è formato dagli assoni delle cellule gangliari retiniche.
- Nella cavità cranica i due nervi ottici si uniscono nel chiasma ottico.
- Dal chiasma ottico prendono origine i due tratti ottici.
- Nel chiasma ottico le fibre provenienti dalla metà laterale (temporale) di ciascuna retina passano nel tratto ottico dello stesso lato (omolaterale), quelle provenienti dalla metà mediale (nasale) di ciascuna retina decussano e passano nel tratto ottico del lato opposto (controlaterale).
- Il tratto ottico di destra è formato dalle fibre provenienti dalle metà destre delle due retine (viceversa a sinistra).
- La maggior parte delle fibre dei tratti ottici terminano nei corpi genicolati laterali (CGL) del talamo.
- Altre fibre dei tratti ottici terminano nel collicolo superiore (coinvolte in riflessi visivi) oppure nei nuclei pretettali (coinvolte in riflessi pupillari)
- Le radiazioni visive sono le proiezioni dai CGL alla corteccia visiva.
![Page 7: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/7.jpg)
Tratto ottico
• 80% delle fibre del tratto ottico vanno al CGL del talamo
• 20% vanno al collicolo superiore del mesencefalo
![Page 8: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/8.jpg)
![Page 9: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/9.jpg)
Brodmann’s Functional Map
![Page 10: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/10.jpg)
![Page 11: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/11.jpg)
Binocular vision• La parte dello spazio visibile è detta
campo visivo.
• La zona binoculare è la zona di sovrapposizione tra i campi visivi dei due occhi. In questa zona gli oggetti sono percepiti in 3D.
• Gli oggetti situati nelle due zone monoculari sono percepiti in due dimensioni.
• L’immagine degli oggetti posti nel campo visivo destro è proiettata alla corteccia visiva sinistra e viceversa.
![Page 12: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/12.jpg)
Visual pathways are crossed
![Page 13: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/13.jpg)
Visual Pathways
![Page 14: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/14.jpg)
Due tipi principali di cellule gangliari: • Cellule magnocellulari (M), di grosse dimensioni, conducono informazioni riguardanti il movimento, la localizzazione e la percezione della profondità.
• Cellule parvocellulari (P), più piccole, trasmettono informazione riguardanti il colore, la forma e la struttura degli oggetti nel campo visivo.
Cellule Gangliari
![Page 15: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/15.jpg)
• Fovea – Principalmente coni, cellule P– Campi recettivi piccoli (0.01mm)– Cellule sensibili ai colori
• Regione Periferica – Principalmente bastoncelli, cellule M– Campi recettivi grandi (0.5mm)– Cellule monocromatiche
Le vie P ed M sono separate (e lo saranno fino alla corteccia visiva). Si possono considerare come due differenti sistemi visivi
![Page 16: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/16.jpg)
Lateral Geniculate Nucleus
![Page 17: Visual processing in the retina Receptive field of ganglion cells (in retina) selectively respond to different patterns of light. On-centre cell On response.](https://reader036.fdocuments.in/reader036/viewer/2022081602/5542eb4e497959361e8bc4b1/html5/thumbnails/17.jpg)
Corpo Genicolato Laterale
Riceve afferenze dai due occhi, ma queste rimangono separate (non ci sono neuroni binoculari), consiste di 6 strati:
- 4 strati parvocellulari (via P): campi recettivi piccoli, input dai coni, sensibili a colori e dettagli e movimenti lenti
- 2 strati magnocellulari (via M): campi recettivi grandi, molto sensibili ai movimenti veloci