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DESCRIBE THE MECHANISMS OF NEURAL COMMUNICATION, EXPLAINING HOW THEY ALLOW EFFECTIVE INFORMAION PROCESSING. Neural communication focuses on the transport of information from sensors and through chains of neurons (also known as nerve cells), decisions and actions are performed to achieve the required functions. The main types of neural communication are information transmission, e.g. about a required movement, and information processing, e.g. where a pattern of visual information is recognized and interpreted as a specific object. Information must be transmitted within each neuron and also between neurons. Information transmitted within each neuron is achieved via electrical activity, whilst information transmitted between neurons is obtained through a chemical process. Neurons are specialized cells that conduct electrical pulses along their processes. Each neuron is also connected to many other neurons, which results in the generation of complex neural networks, forming the foundation of the brain's processing abilities. Neurons receive electrical impulses, which are gathered together and, if they are strong enough, result in an electrical discharge, known as an action potential. Once this is achieved, the action potential generates the input to the next neuron in the network. Each neuron is composed of a cell body (known as the soma) and is connected to dendrites, which carry and receive the incoming information in the form of electrical impulses to the soma and the axon, which transmits information. ...read more.


This is because more positively charged ions flow out of the neuron than flow in. The action potential is a raid depolarization of the membrane and begins at the axon hillock, which then quickly passes along the axon. To allow subsequent firing, the membrane is promptly repolarized. The action potential begins with a partial depolarization and when this reaches the activation threshold, voltage-gated sodium ion channels open, allowing positively charged sodium ions to flood into the neuron, making the inside of the cell depolarized as it is positively charged; the membrane potential changes from -70mV to +40mV. Once the sodium ion channels close, they become refractory, ensuring that the action potential is propagated in a specific direction along the axon. From this, depolarization triggers potassium channels to open, which allows potassium ions to exit the cell. Therefore there is an initial influx of sodium ions, causing a large depolarization; which is when the excitation threshold is reached, followed by a rapid efflux of potassium ions from the neuron, initiating a repolarization. This is then followed by a brief hyperpolarization. To resume the resting potential, potassium channels close and the sodium ion channels are reset through repolarization. From this, ions diffuse away from the area, allowing the membrane to be ready to 'fire' again. ...read more.


Due to the interaction with the neurotransmitter, the pore is opened allowing ions into the post-synaptic terminal. The postsynaptic cell membrane can become either depolarized or hyperpolarized and this depends on which type of ion channel opens. Ions tend to follow the concentration gradient of high to low, whilst the electrostatic gradient follows the opposite charge. Neurotransmission can either be excitatory, where the action potential becomes more likely as the opening of ion channels leads to depolarization, or inhibitory, where the occurrence of an action potential is less likely due to the opening of ion channels leading to hyperpolarization. The result of synaptic transmission, on whether it will be excitatory or inhibitory, depends on the type of neurotransmitter used and the ion channel receptors they interact with. Finally, with the use of neural communication, effective information processing is achieved through a number of factors. Firstly, because information transmission via continuous action potentials can be time-consuming, making it less effective, salutatory conduction, which is provided through myelination, ensures a faster and more efficient approach of conducting the action potential. This is because the myelin sheath allows the action potential to jump and transmit more efficiently from one node (of Ranvier) to another, leading to a more rapid rate of transmission. In addition, fast and efficient information transmission is also achieved as the synapse is very narrow, thus allowing for effective information processing. ...read more.

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