Year: 2014
Type: article
Abstract: Vision is an important sense; it allows animals to create an image of the surrounding environment based on emitted or reflected photons. The sensory interface that transforms photons into electrical signals that can be interpreted by the brain is the retina of the eye. From the retina, these electrical signals are conveyed via axons to a wide array of neuronal networks, many of which are not fully understood. One of the principal targets of retinal axons is the dorsal lateral geniculate nucleus (dLGN) of the thalamus, a structure in charge of relaying information from the retina to visual cortex. The dLGN is however not the only thalamic nucleus that transmits visual information to the cortex. The lateral posterior (LP) nucleus of the thalamus is also part of the vision circuit relaying messages to cortical structures. In contrast to the dLGN, LP does not get visual information directly from the retina. Its main inputs are the superior colliculus and visual cortex itself. The precise anatomy of axonal projection originating each of these two thalamic nuclei is still not completely understood. Here we use viral tracing approaches in the mouse to identify the exact cortical regions targeted by the thalamocortical axons emanating from dLGN and LP. We discover that in primary visual cortex (V1), dLGN and LP have in part complementary and in part overlapping projection pattern: The dLGN projects axons in layers I, IV and VI, while the LP projects to layer I, and the deeper layers of V1. In secondary visual cortex (V2) the projection pattern of LP become denser and the border between V1 and V2 shows a rapid increase in axon density as well as overlapping projections to dLGN axons in V2. These studies further confirm previous work on cats and primates, and validate the mouse as an outstanding model to study vision.
Author: Jamie Evora
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2517340787