https://scholar.dgist.ac.kr/handle/20.500.11750/13550 2026-11-11T11:05:25Z https://scholar.dgist.ac.kr/handle/20.500.11750/61155 Title: SCORE beamforming: Spectral COherence REfinement for high-contrast ultrafast Doppler imaging Author(s): Guezzi, Nizar; Lee, Sangheon; Nam, Sangwoo; Seo, Youngho; Kim, Myeongchan; Eom, Kisang; Hyun, Jung Ho; Yu, Jaesok Abstract: Delay-and-sum (DAS) beamforming is widely used in ultrasound flow imaging due to its computational simplicity; however, its high sidelobe levels significantly degrade image contrast. Coherence factor (CF) beamforming partially alleviates this limitation by emphasizing spatial coherence, yet residual incoherent energy remains and continues to impair image quality. In this study, we propose a dual-stage beamforming approach that integrates CF weighting with a frequency-domain filtering stage designed to discriminate and suppress incoherent energy while preserving coherent signal components. The proposed method, termed SCORE (Spectral COherence REfinement), introduces an additional coherence-based discrimination mechanism beyond conventional CF beamforming. Simulation experiments involving single-target, multi-target, and vascular scenarios demonstrate that SCORE achieves substantial sidelobe suppression while maintaining signal integrity. In vivo validation using an open-source contrast-enhanced rat brain and kidney dataset, as well as contrast-free human spleen further confirms improved flow detectability, reduced background noise, and enhanced power Doppler imaging performance, as evidenced by increases in SNR and CNR approaching 10 dB compared to CF and GCF beamforming. Overall, the SCORE beamformer provides a robust framework for high-contrast vascular ultrasound imaging, offering superior sidelobe and noise suppression relative to DAS, CF and GCF. To enhance computational efficiency, the beamforming pipeline was implemented on a graphics processing unit (GPU) using an optimized CUDA framework, achieving real-time beamforming performance with processing times below 30 ms per frame. 2026-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/61078 Title: Procognitive restoration of PV neuron plasticity in neurodevelopmental disorders Author(s): Shih, Yu-Tzu; Alipio, Jason Bondoc; Klaft, Zin-Juan; Green, Nathaniel; Mohapatra, Alok Nath; Goode, Travis D.; Panchanatham, Muthu; Pathak, Devesh; Wong, Lai Ping; Sadreyev, Ruslan; Hyun, Jung Ho; Ahmed, Omar; Dulla, Chris; Sahay, Amar Abstract: The hippocampus forms memories of our experiences in populations of coactive pyramidal neurons (PNs)1, 2-3. Fast-spiking parvalbumin-expressing inhibitory neurons (PV INs) in the dentate gyrus-CA3/CA2 circuit of the hippocampus precisely control PN activity through mossy fibre-dependent feedforward inhibition4, 5, 6, 7, 8, 9, 10-11. PV INs coordinate experience-dependent changes in their intrinsic excitability, synaptic connectivity, physiology and plasticity properties9,12, 13, 14-15-referred to here as experience-dependent PV IN plasticity-to regulate PN activity. PV IN impairments in early life, when neural circuitry is highly sensitive to experience, are thought to result in network hyperexcitability, seizures and impaired cognition, which are hallmarks of neurodevelopmental disorders (NDDs)16, 17-18. Here we designed an input-specific translatome screen to identify regulators of experience-dependent PV IN plasticity genes (XPGs) in the CA3/CA2 subregion of adult hippocampus. We demonstrate that a substantial proportion of upregulated candidate XPGs exhibit haploinsufficiency in autism spectrum disorder, epilepsies, bipolar disorder and schizophrenia, which suggests that there is impaired experience-dependent PV IN plasticity in NDDs. In proof-of-concept experiments, targeted upregulation of a candidate XPG, the homeobox gene Meis2 (ref. 19), in CA3/CA2 PV INs in an NDD risk mouse model in adulthood is sufficient to restore experience-dependent PV IN plasticity. Moreover, ensemble and sharp-wave ripple properties and cognition were improved, and seizures were suppressed. Thus, experience-dependent PV IN plasticity is a convergent mechanism for NDD risk genes that can be re-instated in adulthood to reverse developmental deficits in circuitry, network excitability and cognition. 2026-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/61011 Title: Distinct lateral hypothalamic GABAergic ensembles encode motivational salience and value-scaled consumption Author(s): Lee, Myungsun; Jung, Sieun; Kwon, JiSoo Jennifer; Kondaurova, Anna; Nam, Myungsun; Kim, Donguk; Hyun, Jung Ho; Kim, Sung-Yon Abstract: Motivated behaviors span an approach-avoidance axis. Vgat-expressing lateral hypothalamic GABAergic neurons (LHVgat neurons) regulate motivated behaviors, but how distinct ensembles represent motivationally significant stimuli and consummatory actions across homeostatic needs remains unclear. Using longitudinal two-photon Ca2+ imaging to track individual neurons across behavioral sessions, we identify two dissociable LHVgat ensembles. One responds to aversive thermal stimuli and food-associated cues, including inaccessible food and learned predictors, but not to a behaviorally neutral auditory tone that evokes pupil dilation, supporting motivational salience coding across aversive and appetitive contexts rather than reflecting arousal alone. A second ensemble is preferentially engaged during ingestion across eating and drinking. Food-cue responses vary across stimuli in a manner consistent with their relative appetitive value, and ingestion responses scale with hunger and nutrient concentration; GLP-1 receptor agonism attenuates both. These findings reveal a functional division between motivationally salient cue processing and value-scaled consummatory encoding in LHVgat circuits. 2026-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60615 Title: The hippocampal CA3 area implements sequence learning of discontinuous episodes Author(s): Eom, Kisang; Kim, Yujin; Lee, Hyoung-Ro; Lee, Yolguk; Han, Young-Eun; Shin, Jiwoo; Lee, Jae Sung; Hyun, Jung Ho; Park, Alan J.; Lee, Suk-Ho Abstract: Sequence learning requires linking memories of adjacent events by sharing ensemble cells. It remains unclear how the hippocampal CA3 links non-overlapping memory representations in sequence learning. High frequency mossy fiber inputs to a CA3 pyramidal cell downregulate Kv1.2 in distal apical dendrites to enhance its voltage response to perforant pathway inputs, and the high excitability is restored by subsequent perforant pathway inputs. Consistent with this notion, we found that CA3 ensemble cells activated by a novel context display high excitability, and their high excitability state is restored by re-activation during the second visit to a similar but distinct context. Computational modeling suggests that this bi-directional excitability regulation enables ordered association of orthogonal neuronal ensembles representing sequential events. Supporting this, CA3-specific Kcna2 + /- mice, which lack synaptic regulation of excitability, exhibited impaired sequence learning. These findings reveal the synaptic mechanisms by which the CA3 network encodes sequential memories. 2026-04-30T15:00:00Z