Mapping the primate lateral geniculate nucleus: A review of experiments and methods

Abstract

Mapping neuronal responses in the lateral geniculate nucleus (LGN) is key to understanding how visual information is processed in the brain. This paper focuses on our current knowledge of the dynamics the receptive field (RF) as broken down into the classical receptive field (CRF) and the extra-classical receptive field (ECRF) in primate LGN. CRFs in the LGN are known to be similar to those in the retinal ganglion cell layer in terms of both spatial and temporal characteristics, leading to the standard interpretation of the LGN as a relay center from retina to primary visual cortex. ECRFs have generally been found to be large and inhibitory, with some differences in magnitude between the magno-, parvo-, and koniocellular pathways. The specific contributions of the retina, thalamus, and visual cortex to LGN ECRF properties are presently unknown. Some reports suggest a retinal origin for extra-classical suppression based on latency arguments and other reports have suggested a thalamic origin for extra-classical suppression. This issue is complicated by the use of anesthetized animals, where cortical activity is likely to be altered. Thus further study of LGN ECRFs is warranted to reconcile these discrepancies. Producing descriptions of RF properties of LGN neurons could be enhanced by employing preferred naturalistic stimuli. Although there has been significant work in cats with natural scene stimuli and noise that statistically imitates natural scenes, we highlight a need for similar data from primates. Obtaining these data may be aided by recent advancements in experimental and analytical techniques that permit the efficient study of nonlinear RF characteristics in addition to traditional linear factors. In light of the reviewed topics, we conclude by suggesting experiments to more clearly elucidate the spatial and temporal structure of ECRFs of primate LGN neurons.

Structure and function of dual‐source cholinergic modulation in early vision

“…Most visual information travels from the retina, along the optic nerve, to the LGN (and other subcortical structures such as the superior colliculus), and then to V1 (also known as the striate cortex), before being distributed through various “extrastriate” visual cortical areas (V2, V3, V3A, V4, etc; for reviews of the visual pathway see for example (Boyd, Khaytin, & Casagrande, ; Hendry & Reid, ; Jeffries, Killian, & Pezaris, ; Usrey & Alitto, ; Weyand, )). Much of what we know about this circuitry arises from the work of Vivien Casagrande (for example see (Casagrande & Kaas, ; Lachica, Beck, & Casagrande, ; Xu et al, )).…”

Interrogating the mouse thalamus to correct human neurodevelopmental disorders

“…Since it carries sensory information to the cortex, the LGN is commonly referred to as a first-order, specific, or core thalamic nucleus. The LGN establishes topographic and reciprocal connections with V1, where its TC neurons project to cortical layer IV, and receive inputs from layer VI (30, 31). Similar organizational schemes are observed across the auditory and somatosensory systems.…”

Assessment of retinal ganglion cell damage in glaucomatous optic neuropathy: Axon transport, injury and soma loss

“…From the RGC soma, axons form the retinal nerve fiber layer, pass through the optic nerve head (ONH), and continue centrally as the optic nerve (ON) and optic tracts. These projections terminate primarily in either the lateral geniculate nucleus (LGN) in higher primates (Jeffries et al, 2014) or the superior colliculus (SC) in rodents (Wang et al, 2010a). RGC axons are conduits for transporting important cellular components from cell body to terminal and vice versa (Morgan, 2004).…”