Tennant, S. | Search bioRxiv

bioRxiv2024

Tabula Glycine: The whole-soybean single-cell resolution transcriptome atlas

Soybean (Glycine max) is an essential source of protein and oil with high nutritional value for human and animal consumption. To enhance our understanding of soybean biology, it is essential to have accurate information regarding the expression of each of its 55,897 protein-coding genes. Here, we present "Tabula Glycine", the soybean single-cell resolution transcriptome atlas. This atlas is composed of single-nucleus RNA-sequencing data of nearly 120,000 nuclei isolated from 10 different Glycine max organs and morphological structures comprising the entire soybean plant. These nuclei are grouped into 157 different clusters based on their transcriptomic profiles. Among genes, the pattern of activity of transcription factor genes is sufficient to define most cell types and their organ/morphological structure of origin, suggesting that transcription factors are key determinants of cell identity and function. This unprecedented level of resolution makes the Tabula Glycine a unique resource for the plant and soybean communities.

plant biology↗

bioRxiv2021

Analogue representation of a spatial memory by ramp-like neural activity in retrohippocampal cortex

Neurons in the retrohippocampal cortices play crucial roles in spatial memory. Many retrohippocampal neurons have firing fields that are selectively active at specific locations, with memory for rewarded locations associated with reorganisation of these firing fields. Whether this is the sole strategy for representing spatial memories is unclear. Here, we demonstrate that during a spatial memory task retrohippocampal neurons encode location through ramping activity that extends within segments of a linear track approaching and following a reward, with the rewarded location represented by offsets or switches in the slope of the ramping activity. These ramping representations could be maintained independently of trial outcome and cues that mark the reward location, indicating that they result from recall of the track structure. During recordings in an open arena, neurons that generated ramping activity during the spatial memory task were more numerous than grid or border cells, with a majority showing spatial firing that did not meet criteria for classification as grid or border representations. Encoding of rewarded locations through offsets and switches in the slope of ramping activity also emerged in recurrent neural networks trained to solve a similar location memory task. Impaired performance of these networks following disruption of outputs from ramping neurons is consistent with this coding strategy supporting navigation to recalled locations of behavioural significance. We hypothesise that retrohippocampal ramping activity mediates readout of learned models for goal-directed navigation.

neuroscience↗