Frontiers in Computational Neuroscience Computational Neuroscience

Abstract

Neurons in PFC exhibit robust object-specific sustained activities during the delay periods of visual WM tasks like DMS or DNMS (Miller et al., 1996). However the informational content of WM-related activities in PFC is still unclear (Romanski, 2007). Inferotemporal (IT) neurons have been shown to encode object-specific information (Nakamura et al., 1994) as they are located at the end of the ventral visual pathway (Ungerleider and Mishkin, 1982). They have been shown to be critical for visual WM (Fuster et al., 1981; Petrides, 2000) and also exhibit sustained activation during the delay period, even if their responses can be attenuated or cancelled by intervening distractors (Miller et al., 1993), what can be partly explained by feedback cortico-cortical connections originating from PFC (Fuster et al., 1985; Webster et al., 1994). The medial temporal lobe (MTL, composed of perirhinal, PRh; entorhinal, ERh and parahippocampal, PH cortices) also plays an important also not essential role in visual WM. Compared to IT, a greater proportion of neurons in PRh and ERh exhibit sustained activation during the delay period (Nakamura and Kubota, 1995) and are robust to distractors (Suzuki et al., 1997). They are especially crucial when visual objects are novel and complex (Ranganath and D'Esposito, 2005). Particularly, PRh cells are more strongly involved in visual recognition when it requires visual WM processes (Lehky and Tanaka, 2007). They are reciprocally connected with IT neurons and can provide them with information about novelty or category membership since they can rapidly encode