• 전자통신동향분석
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• 제38권6호
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• pp.62-74
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• 2023

In response to diverse external stimuli, sensory receptors generate spiking nerve signals. These generated signals are transmitted to the brain along the neural pathway to advance to the stage of recognition or perception, and then they reach the area of discrimination or judgment for remembering, assessing, and processing incoming information. We review research trends in neuromorphic sensory perception technology inspired by biological sensory perception functions. Among the various senses, we consider sensory nerve decoding technology based on sensory nerve pathways focusing on touch and smell, neuromorphic synapse elements that mimic biological neurons and synapses, and neuromorphic processors. Neuromorphic sensory devices, neuromorphic synapses, and artificial sensory memory devices that integrate storage components are being actively studied. However, various problems remain to be solved, such as learning methods to implement cognitive functions beyond simple detection. Considering applications such as virtual reality, medical welfare, neuroscience, and cranial nerve interfaces, neuromorphic sensory recognition technology is expected to be actively developed based on new technologies, including combinatorial neurocognitive cell technology.

• Journal of Oral Medicine and Pain
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• 제30권1호
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• pp.87-106
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• 2005

삼차신경계의 일차연접부위에서 구강 및 악안면 영역의 저역치기계자극수용기에서 유래하는 감각정보의 전달 및 처리 기전을 이해하고자, 고양이 콧수염에서 유래하는 들신경섬유를 사용하여 단일축삭 내 기록법에 의해 HRP를 표식한 후, 삼차신경중간핵에서 시편을 제작하고 표식종말에 대한 연속절편을 형성하였다. 총 30개의 표식 신경종말을 대상으로 전자현미경을 이용하여 삼차신경중간핵에서의 신경섬유 종말 및 연접이전축삭종말의 미세구조적 특징, 발현빈도, 연접양식 등을 분석하여 다음과 같은 결과를 얻었다. 1. 표식종말은 직경 45$\sim$55 ㎚의 균일한 형태의 밝고 둥근 모양의 연접소포를 함유하고 있었으며, 가지돌기와는 연접이후 치밀질이 잘 발달되어 있고, 연접틈새가 크며, 여러 곳에서 넓은 연접구조를 보이는 비대칭연접을, 다형의 연접소포를 함유하는 비표식 축삭종말과는 연접이후 치밀질이 뚜렷하게 발달되지 않으며, 연접면적이 좁은 대칭연접을 형성하였다. 2. 각 표식종말은 인접한 신경구조물들과 최소 1개에서부터 최대 15개까지 신경연접을 형성하여 단위 표식종말 당 평균 4.77$\pm$3.37개의 신경연접이 관찰되었으며, 5개 이상의 신경구조물들과 연접을 형성하는 비교적 복잡한 연접양상이 다수의 표식종말(46.7%, n=14)에서 관찰되었다. 3. 표식종말이 세포체와 직접 연접하는 양상은 관찰되지 않았으며, 가지돌기와는 단위 표식종말 당 1.83$\pm$1.37개의 신경연접을 형성하였다. 가지돌기와 연접을 이루는 표식종말의 대부분(85.0%)은 원위부 가지돌기인 가지돌기체와 연접을 이루었으며(n=47, 1.57$\pm$1.38/1 bouton), 근위부 가지돌기(n=6, 0.20$\pm$0.41/1 bouton)나 가지돌기 가시(n=2, 0.07$\pm$0.25/1 bouton)와 연접을 이루는 경우는 드물었다. 4. 표식종말의 76.7%(n=23)에서 다양한 형태의 연접소포를 함유하는 축삭종말인 p-ending과 축삭사이연접을 형성하였으며 (2.93$\pm$2.36/1 bouton), p-ending이 표식종말 및 이에 연접하는 가지돌기와 동시에 연접을 형성하는 연접세동이도 60.0% (n=18)에서 관찰되었다. 이상의 결과를 종합하여 보았을 때, 고양이 콧수염에서 유래하는 들신경섬유 종말은 삼차신경중간핵에서 특징적인 연접양상을 나타내었으며, 이는 감각정보의 분별, 통각의 정동반응 등 복잡한 감각정보의 처리에 관여하는 삼차신경중간핵의 기능과 밀접한 상관관계가 있는 것으로 사료되며, 향후 신경종말의 미세구조에 대한 정량적인 분석과 연접이전 억제에 관여하는 신경전달물질의 동정 등 생리학적인 기능에 대한 더욱 광범위한 연구가 필요하리라고 사료된다.

• Applied Microscopy
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• 제28권3호
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• pp.255-262
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• 1998

This study was performed to observe the morphological changes of the synaptic structures in the interpolar part of the spinal trigeminal nucleus of rat during aging. Transmission electron microscopy has been used to determine the r)umber of synapses, length of postsynaptic densities, number and area of axon terminals. Sprague-Dawley rat 3, 12, 24 and 36 months of age were used in this study. 1. The number of synapses was 51.7, 43.1, 28.4 and 16.8 in the 3, 12, 24 and 36 months of age respectively. Therefore, the number of synapses decreased gradually with age, but decreased significantly in the 24 and 36 months. 2. The length of postsynaptic densities was $30.2{\mu}m,\;23.6{\mu}m,\;10.4{\mu}m\;and\;4.9{\mu}m$ in the 3, 12, 24 and 36 months of age respectively. Therefore, the length of postsynaptic densities decreased gradually with age, but decreased significantly in the 24 and 36months. 3. The number of axon terminals was 84.3, 73.7, 51.4 and 26.6 in the 3, 12, 24 and 36 months of age respectively. Therefore, the number of axon terminals decreased gradually with age, but decreased significantly in the 24 and 36months. 4. The area of axon terminals was $76.1{\mu}m^2,\;64.1{\mu}m^2,\;29.9{\mu}m^2\;and\;13.8{\mu}m^2$ in the 3, 12, 24 and 36 months of age respectively. Therefore, the area of axon terminals decreased gradilally with age, but decreased significantly in the 24 and 36 months. The results suggest that there are the changes of the synaptic structures in the interpolar part of spinal trigeminal nucleus of rat during aging. These changes nay be concerned to the decreased function of mediating pain and temperature sensation in the face and oral cavity during aging.

• International Journal of Oral Biology
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• 제31권4호
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• pp.113-118
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• 2006

In the primary sensory neuron of the mesencephalic trigeminal nucleus (MTN), the peripheral axon supplies a large number of annulospiral endings surrounding intrafusal fibers encapsulated in single muscle spindles while the central axon sends only a few number of synapses onto single ${\alpha}-motoneurons({\alpha}-MNs)$. Therefore, the ${\alpha}-{\gamma}$ linkage is thought to be very crucial in the jaw-closing movement. Spike activity in a ${\gamma}-motoneuron\;({\gamma}-MN)$ would induce a large number of impulses in single peripheral axons by activating many intrafusal fibers simultaneously, subsequently causing an activation of ${\alpha}-MNs$ in spite of the small number of synapses. Thus, the activity of ${\gamma}-MNs$ may be vital for modulation of jaw-closing movements. Independently of such a spindle activity modulated by ${\gamma}-MNs$, somatic depolarization in MTN neurons is known to trigger the oscillatory spike activity. Nevertheless, the trafficking of these spikes arising from the two distinct sources of MTN neurons is not well understood. In this short review, switching among multiple functional modes of MTN neurons is discussed. Subsequently, it will be discussed which mode can support the ${\alpha}-{\gamma}$ linkage. In our most recent study, simultaneous patch-clamp recordings from the soma and axon hillock revealed a spike-back-propagation from the spike-initiation site in the stem axon to the soma in response to a somatic current pulse. The persistent $Na^+$ current was found to be responsible for the spike-initiation in the stem axon, the activation threshold of which was lower than those of soma spikes. Somatic inputs or impulses arising from the sensory ending, whichever trigger spikes in the stem axon first, would be forwarded through the central axon to the target synapse. We also demonstrated that at hyperpolarized membrane potentials, 4-AP-sensitive $K^+$ current ($IK_{4-AP}$) exerts two opposing effects on spikes depending on their origins; the suppression of spike initiation by increasing the apparent electrotonic distance between the soma and the spike-initiation site, and the facilitation of axonal spike invasion at higher frequencies by decreasing the spike duration and the refractory period. Through this mechanism, the spindle activity caused by ${\gamma}-MNs$ would be safely forwarded to ${\alpha}-MNs$. Thus, soma spikes shaped differentially by this $IK_{4-AP}$ depending on their origins would reflect which one of the two inputs was forwarded to the target synapses.

• 생명과학회지
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• 제15권4호
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• pp.607-612
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• 2005

열충격단백질 70 (HSP70)은 복수유전자족으로서 통상적으로 표현되는 Hsc70와 스트레스에 의하여 유도되는 Hsp70가 있다. 포유동물의 신경계통에서는 상당한 량의 HSP70가 정상조건에서도 표현되는 것으로 알려져 있다. 본 연구에서는 흰쥐의 소뇌 세포의 연접에서 Hsp70의 표현에 대한 연구를 하였다. 면역조직화학적으로 소뇌절편을 염색하여 관찰한 결과 Hsp70와 Hsc70 모두 표현되었는데, 소뇌 조롱박세포에서 가장 강하게 표현되었으며, 다음으로 소뇌 과립세포에서 강하게 표현되었다. 또한 깊은소뇌핵의 신경세포들도 강하게 염색되었다. 배양한 P1 소뇌신경 세포를 Hsp70 항체로 염색한 결과 Hsp70는 조롱박세포와 과립 세포에서 모두 표현되었으며, 세포체와 가지돌기를 따라 점박이를 형성하였다. 이들 점 박이들은 PSD95 점박이와 같이 위치하였다. 그리고 PSD 분획을 이용한 면역염색에서도 PSD70이 검출되었다. 본 연구결과는 Hsp70이 정상조건에서도 소뇌신경세포의 연접에 존재함을 의미한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.103-106
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• 2003

An oscillatory neural network circuit has been designed and fabricated in an 0.5 ${\mu}{\textrm}{m}$ double poly CMOS technology. The proposed oscillatory neural network consists of 3 neural oscillator cells with excitatory synapses and a neural oscillator cell with inhibitory synapse. Simulations of a network of oscillators demonstrate cooperative computation. Measurements of the fabricated chip in condition of $\pm$ 2.5 V power supply is shown.

• 전자공학회논문지B
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• 제30B권8호
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• pp.71-75
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• 1993

This paper presents a neural network IC for Korean vowels recognition. The neural network is composed with three levels and which is learned by Back Propagation algorithm. In the neural network IC, the neuron bodys and synapses are implemented with CMOS inverters and ion-implanted polysilicon resistors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.531-531
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• 2000

The challenge is to control unstable nonlinear dynamic systems using only sparse feedback from the environment concerning its performance. The design of such controllers can be achieved by evolving neural networks. An evolutionary approach to train neural networks in realtime is proposed. Evolutionary strategies adapt the weights of neural networks and the threshold values of neuron's synapses. The proposed method has been successfully implemented for pole balancing problem.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.24-24
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• 2003

Actin filament is a major cytoskeleton in synapses and highly enriched in the presynaptic and postsynaptic compartments. Their roles in synaptic vesicle recycling and synaptogenesis have been extensively studied but functional evidence whether actin filaments are involved in these processes is as yet lacking. Dysfunction in synaptic vesicle recycling causes various diseases such as Alzheimer's disease, Schizophrenia, Bipolar disease, depression etc.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.23-23
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• 2001

To evaluate the contribution of cAMP/PKA signal pathway in short-term facilitation, we overexpressed Ap oal receptor in sensory neurons that do not normally express this receptor. We have previously shown that activation of this receptor in sensory cells, by a brief treatment with octopamine (OA), produced short-term facilitation such as membrane depolarization, increase in membrane excitability, spike broadening, and enhanced neurotransmitter release in non-depressed synapse.(omitted)