The visual pathway Domina Petric MD Introduction Cortical

The visual pathway Domina Petric, MD

Introduction Cortical visual processing is commonly thought to proceed along two distinct pathways: • dorsal pathway projecting into parietal cortex • ventral pathway projecting into temporal cortex

Dorsal visual pathway The dorsal pathway is an occipitoparietal network that lies between early visual cortex and specialized cortical structures involved in: • visually-guided action • somatosensation • spatial audition • navigation • spatial working memory

Dorsal visual pathway The dorsal pathway specializes in capturing arbitrary and dynamic spatiotemporal relationships between multiple items.

Ventral visual pathway • It is an occipitotemporal network that bridges the early visual cortex and specialized cortical and subcortical structures involved in various forms of memory and learning, specifically habit formation, emotion, longterm and short-term memory, reward, and value. • These structures are involved in forming specific representations or associations involving stable aspects of visual information.

Ventral visual pathway Processing of object quality: • inclusive term meant to capture the wide variety of stable visual information that can be processed as the basis of these associations • processing of the features or perceptual dimensions (e. g. shape, color, size, brightness) that are available in the information passed to striate cortex from the retina

Clustering One of the most consistent findings regarding the intrinsic function of the occipitotemporal network is the presence of functional clustering in cortex with selectivity for particular object categories: • body parts • faces • scenes • objects • tools • written words • color

Major subcortical and cortical output pathways from the occipitotemporal network are: • • cortico-subcortical output pathways occipitotemporo-neostriatal pathway occipitotemporo-ventral striatum pathway occipitotempo-amygdaloid pathway cortico-cortical output pathways occipitotemporo-medial temporal pathway occipitotemporo-orbitofrontal pathway occipitotemporo-ventrolateral prefrontal pathway

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Literature: • Kravitz DJ, Saleem KS, Baker CI, Ungerleider LG, Mishkin M. The ventral visual pathway: An expanded neural framework for the processing of object quality. Trends in cognitive sciences. 2013; 17(1): 26 -49. doi: 10. 1016/j. tics. 2012. 10. 011. • http: //www. keywordsuggests. com