RETICULAR FORMATION

Updated 04-May-2020.

Mondo shtuff from around the internet, all about RETICULAR FORMATION!

Activation by Attention of the Human Reticular Formation and Thalamic Intralaminar Nuclei: It has been known for over 45 years that electrical stimulation of the midbrain reticular formation and of the thalamic intralaminar nuclei of the brain alerts animals. However, lesions of these sectors fail to impair arousal and vigilance in some cases, making the role of the ascending activating reticular system controversial. Here, a positron emission tomographic study showed activation of the midbrain reticular formation and of thalamic intralaminar nuclei when human participants went from a relaxed awake state to an attention-demanding reaction-time task. These results confirm the role of these areas of the brain and brainstem in arousal and vigilance.

My botty best at summarizing from Wikipedia: the reticular formation is a set of interconnected nuclei that are located throughout the brainstem . the neuronal network extends from the midbrain to the lower part of the medulla o modulatory functions are primarily found in the rostral sector of the reticular formation . the premotor functions are localized in the neurons in more caudal regions . the reticular formation also contains two major neural subsystems . it has been functionally cleaved both sagittally and coronally . the original functional differentiation was a division of caud study suggests caudal portion inhibits rostral portion of reticular formation . sagittal division reveals more morphological distinctions . insomnia in cats can be caused by insomnia . the lateral RF is close to the motor nuclei of the cranial nerves . it mostly mediates their function . ganglions and interneurons serve to mediate their characteristic reflexes and tracts function in maintaining tone, balance, and posture . reticular formation relays eye and ear signals to the cerebellum . other motor nuclei include gaze centers, which enable the eyes to track and fixate injury to the reticular formation can result in irreversible coma . it plays a central role in states of consciousness like alertness and sleep . habituation is a process in which the brain learns to ignore repetitive, meaningless stimuli while remaining sensitive to others . a person can sleep through loud traffic in a large city, but is awakened promptly neurotransmitters released include dopamine, norepinephrine, serotonin, histamine, acetylcholine, and glutamate . ARAS consists of evolutionari ascending system is seen to contribute to wakefulness as characterised by cortical and behavioural arousal . low voltage fast burst brain waves (EEG desynchronization) are associated with wakefulness and REM the physiological change from a state of deep sleep to wakefulness is reversible . the ventrolateral preoptic nucleus (VLPO) of the hypothalamus inhibits neural circuits responsible for damage to the reticular formation of the midbrain may lead to coma or death . direct electrical stimulation of the ARAS produces pain responses in cats and educes verbal reports of pain in humans . disruption of the ARAS has been implicated in the following disorders: Narcolepsy: lesions along the pedunculopontine (PPT/PPN) / laterodorsal tegmental degeneration in the ARAS begins early in the disease process . prenatal exposure to cigarette smoke is known to produce lasting arousal, attentional and cognitive deficits in humans . the reticulospinal tracts are involved mainly in locomotion and postural control, although they do have other functions as well . the four pathways can be grouped into two main system pathways – a the corticospinal and rubrospinal tract pathways belong to the lateral system which provides fine control of movement . the MRST is responsible for exciting anti-gravity, extensor muscles . the fibers of this tract arise from the medullary reticular formation . responding to a startling or painful stimulus, both arms and legs extend and turn internally . a physical or vascular damage to the the cause is the red nucleus counteracting the extensor motorneuron’s excitation . a damage to the medulla below the vestibular nuclei may cause flaccid para the term “reticulum” means “netlike structure,” which is what the reticular formation resembles at first glance . it has been described as either too complex to study or an undifferentiated part of the brain the term “reticular formation” is seldom used anymore except to speak in generalities . the cells lack clear ganglionic boundaries, but do have clear functional organizations . modern scientists usually refer to the individual nuclei that compose magoun: the direct electrical stimulation of the brain could simulate electrocortical relays . he says the principle was used to demonstrate how to produce wakefulness from sleep . the cat’s brainstem was of particular cats with mesancephalic interruptions to the ARAS entered into a deep sleep . cats could be awakened with somatic stimuli . auditory stimuli directly fired portions of the reticular activ the researchers proposed that a column of cells surrounding the midbrain reticular formation received input from all the ascending tracts of the brain stem . they relayed these afferents to the cortex and therefore