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Voltammetric Detection of Neurotransmitter Release
Published in Richard P. Buck, William E. Hatfield, Mirtha UmañA, Edmond F. Bowden, Biosensor Technology Fundamentals and Applications, 2017
Stimulation of the medial forebrain bundle has long been used as a method to probe brain function. For example, be-havioralists have examined the phenomena of self-stimulation of freely moving rats that can control the stimulation to the brain (43), as well as circling behavior induced by electrical stimulation (44). The use of this technique in neurochemical studies of dopamine in the striatum has been reviewed (3). Roth and coworkers have used this technique to study synthesis regulation, especially in the case of autoreceptor regulation (45). Thus, there is a broad body of work to support the use of stimulation of dopaminergic cell processes to learn more about their chemical aspects. A major thrust of our ongoing research is to use this paradigm to understand more about dopaminergic processes, and at the same time to approach the condition where the natural firing rate of the neuron is used to trigger dopamine release.
Circadian System and Diurnal Activity
Published in Anthony N. Nicholson, The Neurosciences and the Practice of Aviation Medicine, 2017
Appreciating the interaction between the circadian and sleep systems is fundamental to solving the problems experienced by aircrew who have to cope with time-zone changes and with irregularity of rest and activity. Sleep appears to be generated by two broadly opposing mechanisms: the homeostatic drive for sleep and the circadian system that regulates wakefulness (Figure 2.3). Together they interact to consolidate sleep. The homeostatic drive describes a process whereby the drive for sleep increases the longer an individual has been awake. In contrast with the established anatomical location of the circadian clock within the SCN, the brain structures regulating the homeostatic sleep drive remain unclear. Studies suggest that a build-up of adenosine, a breakdown product of adenosine triphosphate, in specific brain regions could provide the molecular basis for sleep pressure (increased sleepiness) during wakefulness (Basheer et al., 2004; Wigren et al., 2007; Landolt, 2008). The basal forebrain has been implicated in this process, whilst other brain regions such as the amygdala, hippocampus and cerebral cortex appear not to be involved (Zeitzer et al., 2006; Christie et al., 2008; Krueger et al., 2008).
Introduction
Published in Munsif Ali Jatoi, Nidal Kamel, Brain Source Localization Using EEG Signal Analysis, 2017
According to embryonic developments, the human brain can be divided into three regions anatomically: the forebrain (or prosencephalon), the midbrain (or mesencephalon), and the hindbrain (or rhombencephalon). The forebrain consists of the cerebrum, thalamus, hypothalamus, and pineal gland. The cerebral area is usually called the telencephalon, and the whole area of the thalamus, hypothalamus, and pineal gland is called the diencephalon [37]. The diencephalon is located in the midline of the brain; however, the telencephalon or the cerebrum is the most superior structure, which has the lateral ventricles, basal ganglia, and cerebral cortex. By contrast, the midbrain or mesencephalon is located at the center of the brain exactly between the pons and the diencephalon. It is further divided into the tectum and cerebral peduncles. The forebrain or prosencephalon is composed of telencephalon and diencephalon, and conversely the diencephalon (or interbrain) includes the thalamus, hypothalamus, and pineal glands. The thalamus consists of a pair of oval masses of gray matter lower to the lateral ventricles and surrounding the third ventricle. The thalamus plays a vital role in learning by sending sensory information for processing and in memory processing. The hypothalamus is located lower to the thalamus and acts as the controller of the brain for body temperature, hunger, thirst, blood pressure, heart rate, and production of hormones. The pineal glands are located posterior to the thalamus in a small region called the epithalamus. They produce the hormone melatonin. The amount of melatonin produced is related to age. As a person ages, the amount of melatonin produced decreases and hence sleep is reduced, as sleep is directly related to the hormone (melatonin) produced. The main and largest part of the forebrain is the cerebrum, which controls the main functions of the brain such as language, logic, reasoning, and creative activities. The location of the cerebrum is around the diencephalon and superior to the cerebellum and brainstem. Figure 1.3 shows the brain structure [38].
Noninvasive vagus nerve stimulation in Parkinson’s disease: current status and future prospects
Published in Expert Review of Medical Devices, 2021
Hilmar P. Sigurdsson, Rachael Raw, Heather Hunter, Mark R. Baker, John-Paul Taylor, Lynn Rochester, Alison J. Yarnall
The LC projects to all levels of the forebrain, including limbic structures (thalamus, amygdala, hippocampus) [76]. These regions play a central role in higher cognitive and affective processes [76]. Visceral information from the vagus nerve is furthermore relayed to the hypothalamus, insular cortex, and the anterior cingulate cortex [1]. The LC additionally has reciprocal connections with the PFC and is therefore believed to play a putative role in PFC cognitive functions such as working memory [77]. VNS has been shown to induce mood and emotion enhancing effects potentially due to LC’s extensive connections with limbic structures, particularly the amygdala, in addition to the amygdala’s main output pathway, the bed nucleus of stria terminalis [76]. LC-NE projections also reach the cholinergic nbM in the basal forebrain [78] which may cause the upregulation of ACh via stimulation of excitatory α1- and β1- adrenoceptors [79].
A device review of Relivion®: an external combined occipital and trigeminal neurostimulation (eCOT-NS) system for self-administered treatment of migraine and major depressive disorder
Published in Expert Review of Medical Devices, 2021
Oved Daniel, Roni Sharon, Stewart J. Tepper
The ophthalmic division of the trigeminal nerve has four branches that can be targeted, and the cervically-derived greater occipital nerve has two larger branches that can be targeted (Figure 1). The Relivion® headset integrates three pairs of output electrodes that contact and deliver stimulation pulses to the patient’s scalp at the forehead (two pairs of electrodes) and occiput (one pair of electrodes). The four frontal electrodes stimulate the trigeminal supraorbital and supratrochlear nerve branches, and the two posterior electrodes stimulate the greater occipital nerve branches. Thanks to its unique multi-channel design and six-electrode configuration, the Relivion® is designed to deliver an unprecedented amount of electrical stimulation via its three adaptive output channels, compared to traditional devices. According to the hypothesized mechanism of action, once signals from the trigeminal and occipital nerves enter the brain, it activates afferent nerve fibers that converge on the same second-order neurons in the TCC with common pathways to the nucleus tractus solitarius and locus coeruleus and raphe nuclei, as well as to higher centers in the brain including the thalamus, hypothalamus, amygdala, reticular activating system, limbic forebrain and anterior cingulate cortex. By releasing anti-nociceptive neurotransmitters such as norepinephrine (Locus Coeruleus) and serotonin (Raphe Nuclei), these brain regions are involved in modulation of pain, mood and anxiety [24,25].
The interactions of diet-induced obesity and organophosphate flame retardant exposure on energy homeostasis in adult male and female mice
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Gwyndolin M. Vail, Sabrina N. Walley, Ali Yasrebi, Angela Maeng, Kristie M. Conde, Troy A. Roepke
Homeostatic regulation of feeding behaviors and energy balance is a complex system but predominantly controlled via neuroendocrine pathways originating in the hypothalamus (Waye and Trudeau 2011). Briefly, the hypothalamus consists of multiple nuclei in which discrete neuronal subgroups communicate with each other to integrate peripheral indicators of energy states (Williams et al. 2001). With emotional and reward inputs from the limbic forebrain, the hypothalamus synthesizes feeding drive and communicates with the hindbrain for execution (Berthoud 2002; Grill and Hayes 2012). Within the hypothalamus lies the arcuate nucleus (ARC) which sits adjacent to a leaky portion of the blood-brain-barrier, and thus its neurons are in a unique position to directly sense energy state through peripheral signals such as glucose, insulin, leptin, and ghrelin (Saper, Chou, and Elmquist 2002; Schwartz et al. 2000). ARC neurons express receptors for these molecules, and their combined inputs to the paraventricular nucleus (PVN) and lateral hypothalamus (LH) help dictate food intake (Arora and Anubhuti 2006; Nahon 2006). Because hypothalamic control of energy homeostasis is highly regulated through hormone signaling pathways including estrogen receptor (ER) α and peroxisome proliferator-activated receptor (PPAR) γ (Garretson et al. 2015; Mauvais-Jarvis, Clegg, and Hevener 2013; Roepke et al. 2011; Sarruf et al. 2009), any EDC, such as OPFRs, that interact with these receptors may disrupt the complex balance of these pathways, sensitizing the system to metabolic disorders such as obesity and diabetes.