From the Guidelines
Pain sensation is transmitted to the brain primarily through the spinothalamic tract. This pathway begins when nociceptors (pain receptors) in the body detect harmful stimuli and generate signals that enter the spinal cord through the dorsal root. These signals then cross to the opposite side of the spinal cord (decussate) and ascend through the spinothalamic tract to the thalamus in the brain, as noted in studies on central post-stroke pain 1. From the thalamus, the pain signals are relayed to various parts of the cerebral cortex for processing and conscious awareness. The spinothalamic tract specifically carries sensations of pain, temperature, and crude touch.
This pathway is clinically significant because damage to it can result in loss of pain and temperature sensation on the opposite side of the body below the level of injury, which can dramatically hinder a patient’s ability to perform daily activities and reduce quality of life, as seen in cases of central post-stroke pain 1. Additionally, the paleospinothalamic tract carries dull, aching pain signals while the neospinothalamic tract transmits sharp, localized pain information. Understanding this pathway is essential for diagnosing neurological disorders, such as central post-stroke pain, and developing effective pain management strategies, as outlined in guidelines for adult stroke rehabilitation and recovery 1.
Key points to consider in the transmission of pain sensation include:
- The role of the spinothalamic tract in carrying pain, temperature, and crude touch sensations
- The clinical significance of damage to the spinothalamic tract, including loss of pain and temperature sensation
- The importance of understanding the pathway for diagnosing neurological disorders and developing effective pain management strategies, as supported by recent studies 1.
From the Research
Pain Transmission to the Brain
The transmission of pain sensation to the brain involves several pathways and tracts. The key tract involved in this process is:
- Spinothalamic tract: This tract is responsible for transmitting pain, temperature, and crude touch sensations from the body to the brain 2, 3, 4, 5, 6.
Mechanism of Pain Transmission
The mechanism of pain transmission involves the activation of nociceptors in the peripheral nervous system, which send signals to the spinal cord and then to the brain. The key steps involved in this process are:
- Activation of nociceptors: Nociceptors are specialized sensory receptors that detect painful stimuli and send signals to the spinal cord.
- Transmission of signals to the spinal cord: The signals from the nociceptors are transmitted to the spinal cord, where they are processed and transmitted to the brain.
- Processing of pain information in the brain: The pain information is processed in the brain, where it is perceived as pain.
Role of Gabapentin and Pregabalin in Pain Management
Gabapentin and pregabalin are two medications that are commonly used to manage neuropathic pain. They work by:
- Reducing the release of excitatory neurotransmitters: Gabapentin and pregabalin reduce the release of excitatory neurotransmitters, such as glutamate, which are involved in the transmission of pain signals.
- Increasing the release of inhibitory neurotransmitters: Gabapentin and pregabalin increase the release of inhibitory neurotransmitters, such as GABA, which help to reduce the transmission of pain signals.
- Modulating the activity of ion channels: Gabapentin and pregabalin modulate the activity of ion channels, such as voltage-gated calcium channels, which are involved in the transmission of pain signals 2, 3, 4, 5, 6.