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Functional Neurology
Published in James Crossley, Functional Exercise and Rehabilitation, 2021
Neurons clump together to form nerves. Nerves can be either sensory, motor or interconnecting. Sensory nerves, also known as afferent nerves, relay signals from the peripheral tissues and organs to the central nervous system (CNS). Afferent nerves provide the CNS with information regarding our environment. Motor, or efferent nerves, transmit signals from the CNS to the tissues and organs. These signals ‘activate’ or alter the function of peripheral tissues and organs. Motor signals sent from the CNS innervate muscles, making them contract, for example. Interneurons are so called because they communicate between or connect spinal and motor neurons, influencing and modulating neuronal function on yet another level. Nerves congregate in various areas of the body, the entirety of which we call the nervous system.
Biological Basis of Behavior
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
Neurons are differentiated according to their function into sensory and afferent neurons that carry information from the sensory receptors, and motor or efferent neurons that transmit information to the muscles and glands. Interneurons are the most common type of neurons, and are located primarily within the central nervous system (CNS) and are responsible for communication among the neurons. Interneurons allow the brain to combine the multiple sources of available information to create a coherent picture of the sensory information being conveyed.
The nervous system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
Interneurons, the third class of neurons, lie entirely within the CNS. The human brain and spinal cord contains well over 100 billion neurons, and interneurons account for approximately 99% of all the neurons within the body. Interneurons lie between afferent and efferent neurons and are responsible for integrating sensory input and coordinating a motor response. In the simplest condition, interneurons process responses at the level of the spinal cord in the form of reflexes, which are automatic, stereotyped responses to given stimuli. For example, stimulation of pain receptors generates action potentials in their associated afferent neurons. These impulses are transmitted to the spinal cord where the afferent neurons stimulate interneurons. These interneurons then stimulate efferent neurons that cause skeletal muscle contraction in the affected area to move the body part away from the painful stimulus. This withdrawal reflex involves comparatively few interneurons and does not require any input from higher nervous centers in the brain. On the other hand, a response to some other stimulus may involve more sophisticated neurological phenomena such as memory, motivation, judgment and intellect. This type of response is not automatic, is clearly far more complex and may require the activity of millions of interneurons in many regions of the brain prior to the stimulation of motor neurons to carry out the desired effect.
Inter-organ regulation by the brain in Drosophila development and physiology
Published in Journal of Neurogenetics, 2023
Sunggyu Yoon, Mingyu Shin, Jiwon Shim
The central brain area for processing feeding behaviors is the subesophageal zone (SEZ), which functions similarly to the brainstem in mammals (Ghysen, 2003; Kendroud et al., 2018). Pharyngeal nerves innervate the SEZ, and motor neurons relay information from the SEZ to pharyngeal nerves to drive the movement of mouthparts, called the proboscis, to control ingestion (Miyazaki & Ito, 2010). Specifically, motor neurons in the SEZ are separated and grouped depending on the response to sweet or bitter tastes: 36 motor neurons are activated by sweet chemicals, while bitter tastes trigger 32 motor neurons (Harris et al., 2015). In addition to neurons executing feeding behaviors, interneurons in the SEZ connect sensory inputs with motor outputs and fine-tune their connectome (Sterne et al., 2021). In summary, taste chemicals in food activate gustatory neurons in sensory organs, which consequently modulate feeding behaviors through muscle movements mediated by motor neurons from the SEZ.
Nitric oxide pathway as a plausible therapeutic target in autism spectrum disorders
Published in Expert Opinion on Therapeutic Targets, 2022
Rishab Mehta, Anurag Kuhad, Ranjana Bhandari
The aforementioned genetic alterations alter functions, morphology, and biological pathways of the brain leading to the pathogenesis of autistic syndromes. Many of these genetic changes tend to alter synaptic transmission as well as synaptogenesis [22]. These genetic changes also tend to produce behavioral alterations such as repetitive and restrictive behavior, stereotypy, social interaction, and communication deficits. In syndromic autism, there is a change in neocortical inhibitory and excitatory balance along with long-term change in synaptic plasticity [6,15]. There are many well-described autism susceptible genes such as neurolignins, neurexins including CNTNAP 2 and human serotonin transporter along with human oxytocin receptor genes and many others [23]. MECP2 gene mutations that cause Rett syndrome result in the disruption of GABAergic neurons [24]. The disruption of GABAergic interneurons as well as changes in neuronal cytoskeleton along with dendritic changes are known to be associated with etiology of autistic disorders. The assumption of excitation-inhibition imbalance in ASDs is supported by the fact that at least 30% of the ASD patients also have epilepsy [25].
Stimulatory and inhibitory effects of morphine on pentylenetetrazol-induced epileptic activity in rat
Published in International Journal of Neuroscience, 2021
Samrand Rashan, Yousef Panahi, Emad Khalilzadeh
GABAergic interneurons may be produced by presynaptic mechanisms that reduce the GABA release. Likewise, Vaughan et al. [23] reported that selective kappa and mu receptor agonists could simultaneously reduce the amplitude of evoked inhibitory postsynaptic currents and the rate of spontaneous miniature inhibitory postsynaptic currents without affecting their kinetics or amplitude distributions in mice with intact subtypes of opioid receptors. There is another possibility that the suppression of GABAergic interneurons can result from activating an inwardly rectifying K+ current. Mu and kappa agonists enhance this current. Some studies indicate that opiates can also have direct excitatory effects on intracellular signaling pathways, including the stimulation of adenylyl cyclase, capacitative calcium entry, and the elongation of the action potential duration [28]. According to Panahi et al. [12], it is never guaranteed that kappa receptors can contribute to the stimulatory effects of morphine. Hence, it seems that the systemic administration of morphine without further convulsion-inducing manipulation can trigger at least two epileptogenic mechanisms, one of which is only mediated by particular opiate receptors [10].