The various organs in an individual’s body play a critical role in in a proper management of a person' health conditions or performance of activities. The organs and tissues comprise specific structure which enables them to properly coordinate their activities. Such the specific structural and mechanical traits assists in person's ability to effectively execute roles whereby encoding and decoding input and output information that interacts with the person. This article focuses on the mechanical operation of neurons, the features of neurotransmitters and the manner in which a person brain encodes pain.
Mechanism of Synaptic Transmission
The mechanism of synaptic transmission relies on the chemical substances which are synthesised in the terminals of presynaptic neurons and stored in the synaptic vesicles (Breedlove, Rosenzweig, " Watson, 2013). Apart from chemical transmission, the transfer of impulses also entails electrical transmission over the 40nn thick membranes of the neurons. The release of a transmitter requires activation by the presynaptic action potentials(APs) which are essential in activating influx of calcium ions that in turn triggers exocytosis which is dependent on calcium ions from the synaptic vessels releases into the synaptic cleft. After their release, neurotransmitters activate receptor-gated channels in the postsynaptic cells thereby evoking changes in the permeability of membranes thus allowing the movement of anions or cations. In turn, ionophoric receptors are responsible for mediating fast synaptic transmission while the G-protein coupled receptors play a pivotal role in slow synaptic transmission (Pickel " Segal, 2013).
Excitatory postsynaptic potentials (EPSP) are responsible for the increase in ability of membranes to conduct sodium and potassium ions thereby resulting in a net increase in positive charge that sodium carries across the neuron m membranes and depolarization if the membranes(Breedlove, Rosenzweig, " Watson, 2013. On the other hand, chlorine ions are the inhibitory postsynaptic potentials (IPSP) hence hyperpolarize the membranes. The summation of EPSP and IPSP integrate electrical impulses thus triggering the synaptic signals that converge at the neuronal terminals. The EPSPs are usually small thus do nit depolarize membranes thus the need for intervention by APS (EPSP at the junction of neurons) which have large potentials that can aid in depolarization of muscle membrane to threshold. At the synapse, muscle AP is triggered when the polarization of membranes reaches or exceed threshold. Ayano (2016) also opines that the chemical transmission of synapse depends on the modulation by intrinsic and extrinsic factors which include the frequency and form of AP firing that can either enhance or inhibit transmission of signals across the neurons.
Features of Neurotransmitters
One of the major traits of neurotransmitters is that they act very fast. According to Breedlove, Rosenzweig " Watson (2013), neurotransmitters can send information in milliseconds. Through an enhanced rate of transmission, neurotransmitters have the capacity to speed the manner in which an individual's body respond to stimuli. For instance, neurotransmitters can send impulses concerning pain in microseconds thereby increase the efficiency of withdrawal from the injurious structure. Consequently, neurotransmitters are important for influencing the body’s activities through their efficient transmission of critical information to the brain for decoding. Accordingly, the distance within which neurotransmitters act is miniscule (Breedlove, Rosenzweig, " Watson, 2013). Notably, a neurotransmitter can only act in a range of micrometres hence an implication that the neurons released on the presynaptic receptors can only bind on the receptors on the postsynaptic. Besides, the transmitters that have capacity to diffuse and affect electrical statuses of organs close to them can only act in a range of tens to hundreds of micrometres. The reduction in range within which neurotransmitters can act majorly emanates from their ability to penetrate in the axonal terminals.
How the Brain Encodes Pain
According to Breedlove, Rosenzweig, " Watson (2013) the encoding of information in an individual’s brain emanates from perception which involves the reliance on sensory organs in the body. Pain being a mechanical or chemical stimulus is unpleasant and leads to the development of a condition that triggers the brain to analyse the experience and store it either in the long-term or short-term memory. Part of the brain which is responsible for the registration of messages regarding pain is the hippocampus which acts in cordiation with the prefrontal cortex. The prefrontal cortex and hippocampus are essential in coordination of activities of other parts of the brain thus help in storage of unpleasant experiences such as pain. Breedlove, Rosenzweig, " Watson (2013) argue that the perception of pain occurs when the sensitive nociception cells reach the threshold due to activation by the C fibers in an individual’s brain. However, when the intensity of pain is critically low, the activation of C fibres in the brain fails thus a person cannot feel any unpleasant changes in their bodies or part of their organs (Apkarian, Hashmi and Baliki, 2011).
In the body, encoding of pain occurs in two major phases which include the fast pain and slow pain. The fast pain often emanates when the stimulus is not intense thus preventing the brain from registering the information as being injurious. On the other hand, slow pain emanates from stimuli that have high intensities which make the nociceptors to reach a threshold. According to Saba (2017), after the activation of nocicetpors, they move swiftly through the synapses in the brain to the prefrontal cortex where they are analysed and stored. The impulses reach the brain after moving through the spinal cord and spinothalamic tract to the thalamus which relays vital messages to the cerebral cortex. The short term memory in the brain has the capacity to store information for seconds whereby the brain analyses the information in the thalamus and decides whether to discard the information or process it for an extended period. For instance, if the brain perceives the messages to be less important, it discards it thus creating space for the acquisition of other information that are relatively new. On the other hand, long term memory entails information that the brain has analysed and found to be essential. Therefore, the intensity of a given stimulus that creates pain determines the manner in which the brain encodes the information.
References
Apkarian, A. V., Hashmi, J. A., " Baliki, M. N. (2011). Pain and the brain: Specificity and plasticity of the brain in chronic clinical pain. Pain, 152(3 Suppl), S49.
Ayano, G. (2016). Common neurotransmitters: Criteria for neurotransmitters, key locations, classifications, and functions. APN, 1(1), 1-5.
Breedlove, S. M., Rosenzweig, M. R., " Watson, N. V. (2013). Biological psychology: An introduction to behavioral, cognitive, and clinical neuroscience. Sunderland, Massachusetts: Sinauer.
Pickel, V. M., " Segal, M. (2013). The synapse: Structure and function. Oxford: Academic Press.
Saba, L. (2017). Neuroimaging of Pain. Cham: Springer.
