Repository Collection: null

Stable olfactory receptor activation across odor complexity

2025-10-31T15:00:00Z

Title: Stable olfactory receptor activation across odor complexity Author(s): Kim, Minseok; Lee, Jeongyoon; Park, Inah; Kim, Jihoon; Lee, Keunsoon; So, Jinhyun; Choi, Ji-Woong; Jang, Jae Eun; Kwon, Hyuk-Jun; Moon, Cheil; Choe, Han Kyoung Abstract: Mechanisms underlying single odorant activation of specific olfactory receptors are well understood. However, how the olfactory system processes complex odor mixtures at the receptor level remains unclear. This study examined olfactory receptor activation patterns across odor complexities using phosphoTRAP analysis. For most mixtures, receptor activation patterns closely matched the linear sum of individual component responses. However, distinct receptor sets display non-linear responses unexplained by linear models. Mixture responses were generally located between component responses and often aligned with linear predictions, though some deviations indicated non-linear interactions. Total activated receptors remained relatively constant regardless of odor complexity, suggesting efficient coding that prevented receptor saturation as odorant components increased. These findings provide receptor-level evidence that the olfactory system encodes complex odors primarily through linear integration of receptor activity, with added specificity from non-linear responses in limited receptors, advancing understanding of how the olfactory system normalizes receptor activation in response to natural odors.

Hexagonal metal complex based mechanically robust transparent ultrathin gold μECoG for electro-optical neural interfaces

2025-03-31T15:00:00Z

Title: Hexagonal metal complex based mechanically robust transparent ultrathin gold μECoG for electro-optical neural interfaces Author(s): Kim, Duhee; Bissannagari, Murali; Kim, Boil; Hong, Nari; Park, Jaeu; Lim, Hyeongtae; Lee, Junhee; Lee, Jungha; Kim, Yoon Kyoung; Cho, Youngjae; Lee, Kwang; Lee, Junghyup; Yoon, Jong-Hyeok; Jang, Jae Eun; Tsai, David; Lee, Sanghoon; Kwon, Hyuk-Jun; Choe, Han Kyoung; Kang, Hongki Abstract: Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging, and high-temporal-resolution electrical recording and stimulation. However, fabricating transparent, flexible, and mechanically robust neural electrodes with high electrochemical performance remains challenging. In this study, we fabricated transparent (72.7% at 570 nm), mechanically robust (0.05% resistance change after 50k bending cycles) ultrathin Au microelectrodes for micro-electrocorticography (mu ECoG) using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer. These transparent mu ECoG arrays, fabricated with biocompatible gold, exhibit excellent electrochemical properties (0.73 Omegacm2) for neural recording and stimulation with long-term stability. We recorded brain surface waves in vivo, maintaining a low baseline noise and a high signal-to-noise ratio during acute and two-week recordings. In addition, we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm2 laser power density. This approach shows great potential for scalable, implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.

Activation of TMEM16E scramblase induces ligand independent growth factor receptor signaling and macropinocytosis for membrane repair

2024-12-31T15:00:00Z

Title: Activation of TMEM16E scramblase induces ligand independent growth factor receptor signaling and macropinocytosis for membrane repair Author(s): Kim, Jung-Eun; Ko, Woori; Jin, Siwoo; Woo, Jin-Nyeong; Jung, Yuna; Bae, Inah; Choe, Han Kyoung; Seo, Daeha; Hille, Bertil; Suh, Byung-Chang Abstract: The calcium-dependent phospholipid scramblase TMEM16E mediates ion transport and lipid translocation across the plasma membrane. TMEM16E also contributes to protection of membrane structure by facilitating cellular repair signaling. Our research reveals that TMEM16E activation promotes macropinocytosis, essential for maintaining plasma membrane integrity. This scramblase externalizes phosphatidylserine, typically linked to resting growth factor receptors. We demonstrate that TMEM16E can interact with and signal through growth factor receptors, including epidermal growth factor receptor, even without ligands. This interaction stimulates downstream phosphoinositide 3-kinase and facilitates macropinocytosis and internalization of annexin V bound to the membrane, a process sensitive to amiloride inhibition. Although TMEM16E is internalized during this process, it returns to the plasma membrane. TMEM16E- driven macropinocytosis is proposed to restore membrane integrity after perturbation, potentially explaining pathologies in conditions like muscular dystrophies, where TMEM16E functionality is compromised, highlighting its critical role in muscle cell survival.

Bidirectional Control of Emotional Behaviors by Excitatory and Inhibitory Neurons in the Orbitofrontal Cortex

2024-09-30T15:00:00Z

Title: Bidirectional Control of Emotional Behaviors by Excitatory and Inhibitory Neurons in the Orbitofrontal Cortex Author(s): Kim, Jihoon; Choi, Mijung; Lee, Jimin; Park, Inah; Kim, Kyungjin; Choe, Han Kyoung Abstract: The orbitofrontal cortex (OFC) plays a crucial role in mood disorders; however, its specific role in the emotional behaviors of mice remains unclear. This study investigates the bidirectional control of emotional behaviors using population calcium dynamics and optogenetic manipulation of OFC neurons. Fiber photometry of OFC neurons revealed that OFC excitatory neurons consistently responded to the onset and offset of aversive conditions, showing decreased activation in response to anxiogenic and stressful stimuli, including tail suspension, restraint stress, and exposure to the center of the open field. The selective activation of excitatory neurons in the OFC reduced the time spent in the center of the open field, whereas optogenetic activation of inhibitory neurons in the OFC induced the opposite behavioral changes. We also provided a brain-wide activation map for OFC excitatory and inhibitory neuron activation. Our findings demonstrate that excitatory and inhibitory neurons in the OFC play opposing roles in the regulation of emotional behaviors. These results provide new insights into the neural mechanisms underlying emotional control and suggest that targeting these specific neuronal populations may offer novel therapeutic strategies for emotional disorders. Copyright © Experimental Neurobiology 2024.