Moreover Reppas, Usrey and Reid Duvelisib in vitro (Reppas

et al., 2002) found saccadic eye movements modulated LGN responses to flickering fields of uniform intensity in awake, behaving macaques. In a similar study, Saul (Saul, 2010) found that saccades changed the response times of neurons. These results show that anesthetizing the animal changes the nature of neuronal responses, especially how they might respond to natural scenes and naturalistic noise. In a similar technical convention that has constrained results, nearly all experiments have used annular stimuli (Alitto and Usrey, 2008, Babadi et al., 2010, Solomon et al., 2006 and Solomon et al., 2002) with a limited ability to fully examine the detailed spatial structure and extent of the ECRF. Non-uniformity of an annular structure in the ECRF has been reported (Webb et al., 2005), but a rigorous, definitive mapping has not yet been performed. Contemporary stimulus generation systems are able to present full-field arbitrary stimuli at high refresh rates, and contemporary computers are readily capable of analyzing large volumes of data

(Alivisatos et al., 2012 and Briggman and Bock, 2012) created by extensive stochastic stimuli. Further experiments in alert primates responding to natural stimuli that address these gaps in the current body of work are needed to better understand the visual system and its properties, and the technical and analytic tools to do so are now available. In this paper we have gathered current knowledge of ABT-737 primate LGN receptive fields, classical and extra-classical, to illuminate the areas that need more work to achieve a better understanding. Much less is known about ECRFs, their source, shape, and how they behave in response to stimuli, than CRFs. Most of the studies that have involved LGN mapping concentrate on the CRF, and few have examined the ECRF. Just as there is more known about CRFs than ECRFs, there is more work Carnitine palmitoyltransferase II done using artificial stimuli than with natural stimuli. Because most of the work

done has been with artificial stimuli, it is hard to know if the field is inadvertently missing important factors involved in visual processing that are present when natural stimuli are used. Technological advancement in stimulus generation and data analysis provide the opportunity to study the ECRF and the CRF in greater detail. Coupled with the growing appreciation of the importance of conscious influence on early sensory processing, the field could see a shift toward using natural stimuli in awake animals for a fuller understanding of the visual system. Despite the tremendous advances in the half-century since Hubel and Wiesel’s initial work, there remains much left to learn about the early visual pathway.