Object Recognition

• The retinogeniculate visual pathway involves the transmission of visual information from the retina to the lateral geniculate nucleus (LGN) in the thalamus
• Organization of V1 includes processing of stereo vision, color perception, and line orientation
• Blobs in V1 are sensitive to color, while pinwheel structures represent orientation columns
• The image of the world is inverted in the brain, with the fovea receiving more resources than the periphery
• Retinotopic mapping involves radial and angular measurements of activity in the eye
• Angular mapping involves traveling around a circle to stimulate different positions in the visual field in a circular motion
• Visual areas differ in specificity for orientations, contrast, color, and motion
• Information in V1 is first sent to V2 and V3 before reaching higher order visual areas
• MT+ is involved in motion processing, where the timing of incoming information influences motion perception
• Area MT neurons are related to perception of motion, not just the presented stimuli
• Neural adaptation to color involves spectrally opposed cells in the primate retina and LGN
• The "where" pathway (superior longitudinal fasciculus) and the "what" pathway (inferior longitudinal fasciculus) divide visual information leaving the cortex
• The dorsal stream is involved in object recognition, with neurons becoming more sensitive to complex objects further along the stream
• Higher visual areas detect and recognize objects by assembling lines and colors represented in V1 into recognizable objects
• Sparse coding involves the effective activation of a small group of neurons for object recognition
• Object detection involves areas like the lateral occipital complex (LOC), inferotemporal cortex, parahippocampal place area (PPA), and fusiform face area (FFA)
• Prosopagnosia is the inability to recognize faces
• Associative agnosia involves the inability to identify objects visually despite normal visual representation
• Impairments in object recognition can be explained by hierarchical coding in the brain
• Apperceptive Agnosia: failure of object recognition due to problems with perception
• LOC: responds to stimuli and can recognize an object based on texture, motion, light
• LOC: Lateral occipital complex
• Hierarchical coding of an object: elementary features are combined with gnostic units that recognize complex objects
• Sparse coding: effective activation of a small group of neurons
• Superior longitudinal fasciculus: where - dorsal
• Inferior longitudinal fasciculus: what - ventral
• Opponent-process theory : states that the human visual system interprets color information in an antagonistic manner
• The timing of incoming information can result in motion perception
• what causes motion after effect (MAE): adaption and velocity scale recalibrates
• Binding Criteria: Nearness of lines, Nearness of color, Coherent motion, and Experience!
• Radial mapping fixates in the middle and stimulates the visual field outward from center
• Movement sensitivity is not as high in the retina as it is in the peripheral vision