Medullary Reticular Formation Essay

Movement of the deltoid begins in the cerebrum of the brain, but more specifically: in the frontal lobe, the premotor cortex is relaying instructions to the primary motor cortex. The primary motor cortex contains the upper motor neurons whose axons will travel down the pyramids of the medulla oblongata and synapse on lower motor neurons in the anterior gray horns of spinal cord segments C5-C6. From there, the ventral rami of spinal nerves C5-C6 form the superior trunk of the brachial plexus, which splits into two divisions. We will follow the posterior division that supplies to extensor muscles. This posterior division then runs into the posterior cord from which the axillary nerve is derived. The axillary nerve’s motor end innervates the deltoid through its neuromuscular junction.

Research into narcoleptic dogs has shown that there is a genetic link in dogs, however, it has also shown that cataplexy occurred during vigorous play or when excited. Moreover, it was found that when the medial medulla is stimulated with an electrode muscle tone disappears. This effect appears to occur to prevent muscle movement during REM sleep and some muscle tone regulation while awake. Siegel found that during a cataplectic episode in the narcoleptic dogs this region of the brain became active. Additionally, it was found that in normal individuals this region of the brain is only highly active during REM sleep. A research in Siegel’s laboratory, Elizabeth Schenkel, demonstrated that normal animals with damaged medial medullas moved during REM sleep. Furthermore, other researchers showed that animals with damage higher on the brain stem, which connected to the medulla “raised their heads, walked and appeared to attack imaginary adversaries during REM sleep” (78).

What type of neurons (sensory or motor) are in the ANS? What are the names for the two neurons in the ANS system?

The reticular formation is essential for maintaining wakefulness and in conjunction with the cerebral cortex is referred to as the reticular activating system (p.450)

| This sleep disorder is most common in women, persons with rheumatoid arthritis, people who are iron deficient or persons who are in kidney failure. It affects less than 4% of the population.

() who stated that stimulation of dMT axonal fibers with brief light pulses did not evoke fast synaptic inputs in CeL neurons. Only small, slow inward currents were reported following high frequency light stimulation. The diverging results may be the consequence of differing viral transduction efficiency or stimulation conditions. Interestingly, the apparent connectivity of dMT and BA was substantially greater as compared to dMT and CeL. Furthermore, synaptic responses evoked in BA PNs were larger as compared to those in CeL neurons regarding absolute amplitudes of AMPAR- and NMDAR-mediated currents under similar stimulation conditions. The effect may be due to stronger innervation of the BA by dMT efferents, to increased presynaptic transmitter release or to increased postsynaptic receptor expression. The AMPAR/NMDAR ratio, which may give an indication of input-independent basal synaptic strength based on postsynaptic AMPAR occupancy, did not reveal any differences dMT-BA and dMT-CeL synapses. Interestingly, AMPAR silent synapses were discovered in the CeL. These synapses may be recruited during periods of increased synaptic input and facilitate

Depolarization of presynaptic terminal will open the Calcium ion channels and Calcium ions diffuse into the axon terminal.

The two pathways of the spinothalamic tract are the lateral and anterior spinothalamic tracts. Fibers of this pathway travel from the skin to the thalamus conveying sensation information of pain, temperature, itch and touch. The information of pain and temperature is carried by the lateral tract while the anterior tract conveys itch and touch. The body sends information through the pseudounipolar neurons to the spinal cord. In the spinal cord these neurons enter the Lissauer’s fasciculus where they synapse to the dorsal horn of the grey matter. Here, most of the neurons decussates to the anterior white commissura on the other side. From there it ascends to the brainstem and synapse on to thalamus. Finally, the thalamus sends projections to

Medulla and cerebellum are the two important part of our brain. Medulla is located in the brain stem, it sits below the pons and above the spinal cord. Medulla is a major relay point that receive and send information between the brain and our body back and forth. Medulla directly control many autonomic nervous system (ANS) responses, for instance, it controls the blood vessel dilation to increase or decrease oxygen flow and respond to heart functions; it controls digestion to turn on or off during the "fight" or "flight" scenarios; it also controls sneezing and coughing to dispel particles from the nose; swallowing and vomiting to get rid of the bacteria or poisons that could harm our body. It controls when these activities start, when they stop and how fast they go at the right time. If medulla is damaged, people may lose the sense of touch and muscle coordination. They might have trouble breathing, coughing, swallowing and vomiting, they may not able to sense or detect pain or the changes of temperature.

An integration center in the reflex arc is a neuropathway that creates a reflex action to activating neurons to skip the spinal cord and protect your brain. The nerve cells can be categorized by their connections, structure, and neurotransmitters. The structural classification is depending on shape and size of the cell body, its dendritic tree, axon length, and the nature of the connections it makes. The neurons with one, two, or more than two neurites, are unipolar, bipolar, and multipolar respectively. Most of neurons in vertebrate nervous systems are multipolar, but there are significant exceptions. For illustration, bipolar neurons in the retina synapse with sensory neurons, and photoreceptors in the dorsal root ganglion are explained as pseudo-unipolar as they begin life as bipolar cells but their two neurites fuse. The unipolar neurons dominate in invertebrates. Collaterals a small side branch, as of a blood vessel or nerve. A neuronal pool is a group of interconnected neurons with specific functions. A pool may be diffuse, involving neurons in several regions of the brain, or localized, with neurons restricted to one specific location in the brain or spinal cord. However, the proper function of the circuit of the stretch reflex also relies on convergence and divergence. A single sensory has multiple branches that diverge and make synaptic connections with many individual motor neurons. Therefore, when the muscle contracts as a result of the neurologist’s tapper, it

A study was conducted on narcolepsy where researchers observed sleep regulations of orexin knocked out mice. Their conclusion showed “that lack of orexin neuropeptides results in a syndrome of sleep state dysregulation remarkably similar to human and canine narcolepsy. Thus, the interaction of orexins with OX2R appears to be a key signaling pathway in REM sleep regulation” (Chemelli et al, 1999). The research conducted revealed that the neurotransmitter orexins is a key factor in signaling REM sleep regulation. Most cases of narcolepsy are sporadic or can be inherited. Seigel (1999) found, “the role of HLA gene products in immune regulation, because most HLA-linked diseases are autoimmune in nature, and because of the evidence that environmental triggers might be involved, it has been speculated that narcolepsy might be an autoimmune disorder. Since receptors are continuously regenerated, any immune attack that affected only the receptors would have to continue for the duration of the disease. No such autoimmune process has so far been detected. Alternatively, irreversible damage to axon terminals or to the hypocretin neurons themselves, creating the equivalent of an Hcrt knockout, might cause the disorder.” Seigel research shows that the hypothalamus controls the direction of hormones in the body, such as hypocretin, he thinks that

The reticular formation is a finger-shaped network of neurons that lay in the core of the brainstem, extending from the spinal cord to the thalamus. It regulates the human body’s functions in processes such as arousal, the sleep-wake cycle, and muscle tone by filtering incoming stimuli and relaying important information to other parts of the brain. An experiment had been done by Giuseppe Moruzzi and Horace Magoun to study more in depth of how this intricate part of the brain worked. They electrically stimulated the reticular formation of a sleeping cat and found interesting observations: the cat was alert and awake. However, when the cat’s reticular formation was severed, the cat had drifted into a coma, never to be awakened again. Without

The hypothalamus transmits nerve impulses that go through brain stem, spinal cord, and preganglionic sympathetic nerve fibers to adrenal medulla, then will

Sleepwalking occurs during stages 3 and 4 of the sleep cycle, the deepest levels of sleep. This slow-wave sleep is normally characterized by synchronized EEG activity (4). This indicates that mental activity is very low during these stages of sleep. However researchers have shown that the EEG of a sleepwalker has diffuse, rhythmic, high-voltage bursts of delta activity associated with abrupt motor activity (1). This is very different from the EEG activity normally associated with slow-wave sleep. In addition to the EEG results, they found that there is a decrease in regional cerebral blood flow in the frontopariental cortices during sleepwalking (1). This indicates that sleepwalking is a dissociated state consisting of motor arousal and persisting mind sleep, which seems to arise from the selective activation of thalamocingulate circuits and the persisting inhibition of other thalamocortical arousal systems (3).

Sleep is one of the unavoidable daily-living activities and it is one of the most important factors contributing to a person’s health. A quality sleep is essential for the physical, cognitive and psychological well-being of a person. Learning, memory processing and maintenance of the brain are among the most important functions of sleep. In addition to maintaining the brain, sleep has important roles in controlling the