Amir Hossein Azizi

Salt stress is a primary abiotic constraint on global rice productivity. To establish a robust genomic framework for breeding, we performed a genome-wide meta-QTL (MQTL) analysis integrating QTL data from both the seedling and reproductive stages. A high-density consensus map was constructed, and initial QTLs from independent studies were curated and filtered for redundancy. Confidence intervals were refined via meta-analysis to define stable MQTL regions. From 926 original QTLs at the seedling stage, 87 seedling MQTLs (SeMQTLs) were identified. Notably, SeMQTL1-5, which encompasses the major locus Saltol, and three additional high-confidence SeMQTLs (CI < 1 cM, physical interval ≤ 1 Mb, average PVE > 17%) were associated with ion homeostasis under salt stress. At the reproductive stage, 43 reproductive MQTLs (ReMQTLs) were consolidated from 241 QTLs, with PVE values ranging from 4.84% to 46.36%. Subsequent analysis nominated MQTLSIH1-2 (the most stable region) and MQTLSIH1-5 (containing SKC1) as key candidates for seedling tolerance, while MQTLPF11-1 (PVE > 28%) was prioritized for reproductive-stage breeding. A total of 39 MQTLs co-localized with SNP-based selection hotspots. Within these regions, we developed 21 InDel markers, of which 18 were validated as effective allele-specific markers for discriminating salt tolerance. This work delivers the first consolidated set of high-confidence, MQTL-derived InDel markers for salt tolerance in rice, providing a valuable resource for marker-assisted selection and the pyramiding of resilience loci into elite genetic backgrounds.

Working memory is the cognitive capability to maintain and process information over short periods. Behavioral and computational studies have shown that visual information is associated with working memory performance. However, the underlying neural correlates remain unknown. To identify how visual information affects working memory performance, we conducted behavioral experiments in pigeons (Columba livia) and single unit recordings in the avian prefrontal analog, the nidopallium caudolaterale (NCL). Complex pictures featuring luminance, spatial and color information, were associated with higher working memory performance compared to uniform gray pictures in conjunction with distinct neural coding patterns. For complex pictures, we found a multiplexed neuronal code displaying visual and value-related features that switched to a representation of the upcoming choice during a delay period. When processing gray stimuli, NCL neurons did not multiplex and exclusively represented the choice already during stimulus presentation and throughout the delay period. The prolonged representation possibly resulted in a decay of the memory trace ultimately leading to a decrease in performance. In conclusion, we found that high stimulus complexity is associated with neuronal multiplexing of the working memory representation possibly allowing a facilitated read-out of the neural code resulting in enhancement of working memory performance.

Sequential activation of neurons that occurs during “offline” states, such as sleep or awake rest, is correlated with neural sequences recorded during preceding exploration phases. This so-calledreactivation, orreplay, has been observed in a number of different brain regions such as the striatum, prefrontal cortex, primary visual cortex and, most prominently, the hippocampus. Reactivation largely co-occurs together with hippocampal sharp-waves/ripples, brief high-frequency bursts in the local field potential. Here, we first review the mounting evidence for the hypothesis that reactivation is the neural mechanism for memory consolidation during sleep. We then discuss recent results that suggest that offline sequential activity in the waking state might not be simple repetitions of previously experienced sequences. Some offline sequential activity occurs before animals are exposed to a novel environment for the first time, and some sequences activated offline correspond to trajectories never experienced by the animal. We propose a conceptual framework for the dynamics of offline sequential activity that can parsimoniously describe a broad spectrum of experimental results. These results point to a potentially broader role of offline sequential activity in cognitive functions such as maintenance of spatial representation, learning, or planning.