http://hdl.handle.net/10203/292490 KAIST Dept. of Brain and Cognitive Sciences Sat, 07 Mar 2026 05:23:38 GMT 2026-03-07T05:23:38Z http://hdl.handle.net/10203/339266 Title: An implanted lennula approach to measure neural Ca²⁺ responses in the awake marmoset visual cortex Authors: Park, Soo Hyun; Nti, Stephany A.; Marcelle, Madeline; Esch, Elena M.; Wang, Kuan Hong; Silva, Afonso C.; Leopold, David A. Abstract: We present a novel approach for endoscopic calcium imaging in the marmoset extrastriate visual cortex, combining a chronically implanted microprism lens with an integrated injection cannula. This method achieved stable, longitudinal imaging of visually responsive GCaMP-expressing neurons over multiple weeks. Using a head-mounted miniscope in two subjects, we repeatedly presented naturalistic visual stimuli and longitudinally tracked the activity of more than one hundred neurons across sessions within an 800-μm2 field of view. Stably monitored neurons in cortical areas V3 and MT responded reliably to visual images and movies over periods up to three weeks. Cells having different visual response preferences were spatially intermixed. These results demonstrate the feasibility of longitudinal calcium imaging in the primate visual cortex using a single-surgery, integrated lens-cannula approach, and provide initial insights into single neuron response stability and diversity to naturalistic stimuli in mid-level cortical visual areas. Sun, 01 Mar 2026 00:00:00 GMT http://hdl.handle.net/10203/339266 2026-03-01T00:00:00Z http://hdl.handle.net/10203/339220 Title: Prewired static visual receptive fields for environment-agnostic perception Authors: Kang, Minjun; Baek, Seungdae; Paik, Se-Bum Abstract: Biological brains can effortlessly adapt to continuously changing stimulus environments, whereas conventional deep neural networks (DNNs) remain highly susceptible to domain shifts. Here, we demonstrate that static, hard-wired receptive fields, which spontaneously emerge in the early visual pathway, facilitate environment-agnostic object recognition in the brain. To test this mechanism, we introduced pre-developed Gaborfilters in the early layers of DNNs, keeping them fixed during training. Despite the reduced learning flexibility, our networks exhibited robust continual learning capabilities under significant domain shifts, unlike conventional DNNs, which fail to generalize under similar conditions. Our network achieved generalized representations across domains in the latent space, while conventional DNNs only captured domain-specific variance. The static visual filters helped prevent local texture biases, leading to shape-based perception similar to that of primates. These findings highlight an intrinsic biological strategy that enables reliable continual learning in dynamic and unpredictable environments. Sun, 01 Feb 2026 00:00:00 GMT http://hdl.handle.net/10203/339220 2026-02-01T00:00:00Z http://hdl.handle.net/10203/338850 Title: Optimal Inhibitory-to-Excitatory Ratio Governs Slow and Fast Oscillations for Enhanced Neural Communication Authors: Kim, Jung Young; Lee, Sang Wan; Battaglia, Demian; Choi, Jee Jyun; Yook, Soon-Hyung Abstract: Neural oscillations at distinct frequency bands facilitate communication within and between neural populations. While single-frequency oscillations are well-characterized, the simultaneous emergence of slow (beta) and fast (gamma) oscillations within the same network remains unclear. Here, we demonstrate that multi-frequency oscillations naturally arise when the ratio of inhibitory-to-excitatory synaptic strength falls within a specific regime using a biologically plausible Izhikevich model. We show that this regime maximizes both information capacity and transmission efficiency, suggesting an optimal balance for neural communication. Deviations from this range lead to single-frequency oscillations and reduced communication efficiency, mirroring disruptions observed in neurological disorders. These findings provide mechanistic insight into how the brain leverages multiple oscillatory frequencies for efficient information processing and suggest a potential biomarker for impaired neural communication. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10203/338850 2026-01-01T00:00:00Z http://hdl.handle.net/10203/339050 Title: Epigenetic aging and rejuvenation of the brain: drivers, consequences, and interventions Authors: Lee, Seunghyun; Cho, Seunga; Kim, Seung-Kyoon; Yang, Jae-Hyun Abstract: Evolution has tuned epigenetic resilience to preserve chromatin organization, transcriptional networks, and cellular identity under relentless stress. Over time, however, all eukaryotic life faces an inevitable rise in entropy that erodes the chromatin landscape at the genomic scale. This entropic decay of epigenetic information, epigenetic aging, is increasingly viewed as a key causal process underlying biological aging and systemic dysfunction. The brain is particularly vulnerable to epigenetic aging, with post-mitotic neurons accumulating lifelong chromatin erosion, and the glial epigenome drifting toward pro-inflammatory states. This review synthesizes evidence on the drivers and consequences of epigenetic aging in the brain and outlines frameworks for restoring youthful chromatin landscapes and cognitive capacity. [BMB Reports 2026; 59(1): 27-39] Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10203/339050 2026-01-01T00:00:00Z