Keji Li

Massachusetts Institute of Technology | MIT · Picower Institute for Learning and Memory

The flow of visual information is clear at the earliest stages: the retina provides the driving (main signature) activity for the lateral geniculate nucleus (LGN), which, in turn, drives the primary visual cortex (V1). These driving pathways can be distinguished anatomically from other modulatory pathways that innervate LGN and V1. The path of visu...

Despite its anatomical prominence, the function of primate pulvinar is poorly understood. A few electrophysiological studies in simian primates have investigated the functional organization of pulvinar by examining visuotopic maps. Multiple visuotopic maps have been found in all studied simians, with differences in organization reported between New...

The primary visual cortex (V1) receives its driving input from the eyes via the lateral geniculate nucleus (LGN) of the thalamus. The lateral pulvinar nucleus of the thalamus also projects to V1, but this input is not well understood. We manipulated lateral pulvinar neural activity in prosimian primates and assessed the effect on supra-granular lay...

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the methyl CpG binding protein 2 ( MECP2 ) gene. There are currently no approved treatments for RTT. The expression of K ⁺ /Cl ⁻ cotransporter 2 (KCC2), a neuron-specific protein, has been found to be reduced in human RTT neurons and in RTT mouse models, suggesting that KCC...

With the recent 50th anniversary of the first publication on Rett syndrome, and the almost 20 years since the first report on the link between Rett syndrome and MECP2 mutations, it is important to reflect on the tremendous advances in our understanding and their implications for the diagnosis and treatment of this neurodevelopmental disorder. Rett...

Comprised of at least five distinct nuclei, the pulvinar complex of primates includes two large visually driven nuclei; one in the dorsal (lateral) pulvinar and one in the ventral (inferior) pulvinar, that contain similar retinotopic representations of the contralateral visual hemifield. Both nuclei also appear to have similar connections with area...

Microdeletion of a region in chromosome 16p11.2 increases susceptibility to autism. Although this region contains exons of 29 genes, disrupting only a small segment of the region, which spans five genes, is sufficient to cause autistic traits. One candidate gene in this critical segment is MVP, which encodes for the major vault protein (MVP) that h...

Rett syndrome (RTT) arises from loss-of-function mutations in methyl-CpG binding protein 2 gene (Mecp2), but fundamental aspects of its physiological mechanisms are unresolved. Here, by whole-cell recording of synaptic responses in MeCP2 mutant mice in vivo, we show that visually driven excitatory and inhibitory conductances are both reduced in cor...

Significance Understanding neurophysiological correlates of neurodevelopmental disorders is one of the pressing challenges of neuroscience. By analyzing a mouse model of Rett syndrome (RTT), we show that cortical pyramidal neurons in methyl-CpG binding protein 2 (MeCP2) mutant mice have reduced excitatory as well as inhibitory synaptic drive. Thus,...

The pulvinar nucleus in primates has connections with all known visual cortices, yet little is known about its functions. To clarify the functional organization of pulvinar, a few studies have investigated its visuotopic maps in simians using electrophysiological methods. These studies consistently showed two maps, but the organization of these map...

Background / Purpose: Pulvinar is widely connected with early visual cortices in primates, but only a few simian species have their visual pulvinar electrophysiologically mapped. Differences were found in the pulvinar retinotopic maps between simian species. Main conclusion: Subdivisions were identified in bush baby inferior pulvinar that corr...

The thalamic nucleus pulvinar has been implicated in the control of visual attention. Its reciprocal connections with both frontal and sensory cortices can coordinate top-down and bottom-up processes for selective visual attention. However, pulvino-cortical neural interactions are little understood. We recently found that the lateral pulvinar (PL)...

Supplementary Figure 1 Thalamo-cortical connections relevant to the experiments Parvo- and magnocellular layers of LGN provide the driving input to layer 4 of V1. Collaterals of these projections terminate in the TRN, which projects back to the LGN in a spatio-topic manner. Layer 5 of V1 sends driving input to lateral pulvinar, which projects back...

Pulvinar is the largest thalamic nucleus in primates, having expanded in proportion to neocortex through evolution. Its well-differentiated sub-nuclei have reciprocal connections with different visual cortical areas. Lateral pulvinar (PL) receives input from layer 5 of primary visual cortex (V1) and projects to supragranular layers 1–3 of V1 which,...