Retinal Input Instructs Alignment of Visual Topographic Maps

Retinal Input Instructs Alignment of Visual Topographic Maps

Sensory information is represented in the brain in the form of topographic maps, in which neighboring neurons respond to adjacent external stimuli. In the visual system, the superior colliculus receives topographic projections from the retina and primary visual cortex (V1) that are aligned. Alignment may be achieved through the use of a gradient of shared axon guidance molecules, or through a r...

Visual Maps Development: Reconsidering the Role of Retinal Efnas and Basic Principle of Map Alignment

Topographic maps of visual spatial attention in human parietal cortex.

Functional magnetic resonance imaging (fMRI) was used to measure activity in human parietal cortex during performance of a visual detection task in which the focus of attention systematically traversed the visual field. Critically, the stimuli were identical on all trials (except for slight contrast changes in a fully randomized selection of the target locations) whereas only the cued location ...

Topographic Maps

We call "natural" image any photograph of an outdoor or indoor scene taken by a standard camera. We discuss the physical generation process of natural images as a combination of occlusions, transparencies and contrast changes. This description ts to the phenomeno-logical description of Gaetano Kanizsa according to which visual perception tends to remain stable with respect to these basic operat...

Ephrin-As and patterned retinal activity act together in the development of topographic maps in the primary visual system.

The development of topographic maps in the primary visual system is thought to rely on a combination of EphA/ephrin-A interactions and patterned neural activity. Here, we characterize the retinogeniculate and retinocollicular maps of mice mutant for ephrins-A2, -A3, and -A5 (the three ephrin-As expressed in the mouse visual system), mice mutant for the beta2 subunit of the nicotinic acetylcholi...