1. The visual cortex processes visual information by detecting correlated features and representing this information sparsely and independently across neural populations.
2. Individual neurons in the visual cortex learn tuning functions that are sensitive to the most informative dimensions of the visual environment, such as orientation, spatial frequency, and color.
3. The brain forms a hierarchical model of visual information, with neurons in higher cortical areas representing more complex features built upon those in lower areas. This efficient coding scheme allows for effective processing of visual information.
15. A neuron learns to be selective Dyan & Abbot: Theoretical Neuroscience (2001) MIT Press
16. Different tuning functions for orientation Dyan & Abbot: Theoretical Neuroscience (2001) MIT Press Neuron 1 Neuron 2 Neuron 3 Neuron 4
17. Multiple systems on top of each other Hübener ym, J Neurosci 17 (1997) 9270-9284 Ocular dominance and orientation Spatial frequency and orientation
24. Sparse coding of different tuning functions in the primary visual cortex Position Eye (stereo image) Spatial frequency (scale) Orientation Direction and speed of motion Wavelength (color) Courtesy of Aapo Hyvärinen
35. Centre response covaries with the surround response Vanni & Rosenström, in preparation VOIcentre
36. Active voxels for centre are suppressed during simultaneous presentation Vanni & Rosenström, in preparation VOIcentre
37. Suppression (red) is surrounded by facilitation (blue) Vanni & Rosenström, in preparation
38. Efficient coding Response to stimulus A, A’ Response to stimulus B, B’ A’ = A – dB B’ = B – dA Barlow, H., and Földiák, P. (1989). In: The computing neuron. R. Durbin, et al., eds. (Boston, Addison-Wesley Longman Publishing Co., Inc), pp. 54-72.
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Hinweis der Redaktion
Helppo fenomenaalinen prosessi mutta vaikea computationaalinen prosessi Visuaalisen informaation käsittelyyn menee aikaa Tutkimalla aivojen rakenteita ja toimintaa voidaan yrittää ymmärtää tiedonkäsittelyn periaatteita Tiedonkäsittelyn ajallinen järjestys kertoo mitä aivokuoren yksiköitä tarvitaan missäkin tiedonkäsittelyn vaiheessa Perustietämys apinoista