نوع مقاله: مقاله کامل پژوهشی

نویسندگان

1 استادیار، گروه بیوالکتریک، دانشکده مهندسی پزشکی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی

2 استاد، گروه بیوالکتریک، دانشکده مهندسی پزشکی، دانشگاه صنعتی امیرکبیر

3 استاد، گروه فیزیک پزشکی، دانشکده علوم پزشکی، دانشگاه تربیت مدرس

4 دانشیار، گروه بیهوشی، دانشکده پزشکی، دانشگاه علوم پزشکی شهید بهشتی

10.22041/ijbme.2009.13384

چکیده

فرایند شکل گیری درد از نرون های حسی اولیه شروع و به نرون های سیستم عصبی مرکزی که اولین بخش آن در شاخ خلفی نخاع است ختم می شود. امروزه تلاش برخی محققان برای کنترل درد، یافتن سازوکاریست که بتواند وضعیت نرون های شاخ خلفی نخاع را از یک حالت پایدار ناخواسته به حالت پایدار مطلوب تغییر دهد به این منظور لازم است ابتدا مدلی از رفتار نرون ها در شاخ خلفی نخاع استخراج شود تا با تغییر پارامترهای مدل مذکور، بتوان درد ایجاد شده را تحت کنترل در آورد. در این تحقیق به کمک اسلوب شناسی بایفورکیشن و استخراج دینامیک حاکم بر سازوکار شکل گیری درد از طریق انجام آزمایش های بالینی، یک مدل سایبرنتیکی ارائه می شود که قادر به بیان حالت های عملکردی نرون های شاخ خلفی نخاع (عادی، حساس شده و فرونشانده شده)، نقش حافظه، اثر ورودی های حسی دیگر و اثر ورودی های نزولی از سطوح فوقانی سیستم عصبی است. در این مدل ورودی ها شامل درجه تحریک حرارتی متناسب با نرخ پتانسیل عمل از آوران های dC/A، شدت جریان تحریک الکتریکی مهاری متناسب با نرخ پتانسیل عمل از آوران های Ab، ورودی های مهاری نزولی از مغز میانی و ورودی های مهاری یا تحریکی نزولی از سطوح فوقانی سیستم عصبی (تالاموس و قشر مغز) بوده و خروجی مدل نرخ پتانسیل عمل ساطع شده از نرون های انتشاری شاخ خلفی نخاع متناسب با سطح درد حس شده است. ویژگی شاخص این مدل استفاده از مدلسازی سایبرنتیکی بر اساس یک سری اطلاعات ورودی و خروجیست که می تواند ایراد وارد بر سایر مدل ها که در آنها ساده سازیِ روابط، تعامل اجزای سیستم را کاهش می دهد مرتفع کند. از طرف دیگر برخلاف مدل های قبلی که بر اساس پتانسیل تحریکی غشاء مدلسازی شده بودند در مدل مذکور خروجی مستقیما به صورت پتانسیل عمل ساطع شده از نرون های انتشاری شاخ خلفی نخاع است که علاوه بر اینکه از دقت بالاتری برخوردار است قابلیت انطباق با ثبت های سلولی را نیز دارد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The Cybernetical Model Of Pain And State-Dependent Sensory Processing In The Dorsal Horn Of The Spinal Cord

نویسندگان [English]

  • Siamak Haghipour 1
  • Seyed Mohammad Reza Hashemi Golpayegani 2
  • Seyed Mohammad Firouzabadi 3
  • Sirous Momenzadeh 4

1 Assistant Professor, Bioelectric Group, Biomedical Engineering School, Science and Technology Branch, Islamic Azad University

2 Professor, Bioelectric Division, Biomedical Engineering School, Amirkabir University of Technology

3 Professor, Medical Physics Group, Medical Sciences School, Tarbiat Modares University

4 Associate Professor, Anesthesiology Grou, Medicine School, Shahid Beheshti University of Medical Sciences

چکیده [English]

The procedure of pain formation embarks on primary sensory neurons and then ends in central nervous system which is the first stage in the dorsal horn of the spinal cord. Nowadays the great challenge of some researchers for pain control has been to elucidate the mechanisms that are able to switch the state of the dorsal horn of the spinal cord from an unwanted state to a favorite one. In order to achieve such an aim, a model of the function of the dorsal horn of the spinal cord is extracted in order to be able to control the created pains with changing the parameters of the aforementioned model. In this study a cybernetic model is presented with the aid of bifurcation methodologies and reconstructing the dynamics linked with the process of pain formation via clinical experiment that can express different states in the dorsal horn of the spinal cord as normal, suppressed, sensitized, the functionality of memory, the effect of other primary afferents and the effect of descending signals. Input signals in this model consist of thermal stimulation degree proportional to action potential firing rate from Ab afferents, inhibitory descending signals from midbrain and inhibitory or excitatory descending signal from thalamus and cortex and the output signal is the action potential firing rate from transmission cells in dorsal horn of the spinal cord proportional to pain level have been sensed. The significant and remarkable characteristic of this model is applying a cybernetical model based on a sequence of input-output data which can obviate the drawbacks of other models in which simplification and reduction of terms reduce the operation of components of a system. On the other hand, unlike previous models which have been modeled based on membrane (slow) potential, this model is based on the action potential firing rate from transmission cells of the dorsal horn of the spinal cord that has the adaptability with cellular recording as well as having a higher accuracy.

کلیدواژه‌ها [English]

  • Thermal Stimulation
  • electrical stimulation
  • Pain
  • Cybernetic Model
  • Gate Control Theory

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