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The Central Connections of Area Postrema Define the Paraventricular System Involved in Antinoxious Behaviors
Published in John Kucharczyk, David J. Stewart, Alan D. Miller, Nausea and Vomiting: Recent Research and Clinical Advances, 2017
The evolutionary advantage of vomiting is that it expels toxic gastrointestinal (GI) contents, and the advantage conferred by nausea and conditioned taste aversion appears to be that they prevent reingestion. This chapter is concerned with the identification of the neural substrate for these protective behaviors. Simple schemes suggest that emetic stimuli converge on a “vomiting center”1 from which all emetic effector systems radiate, and that the sequence of effector activation is uniquely programmed by this “center”. This view has dominated the literature for several decades. A more plausable scheme suggests that emetic stimuli feed into a cascade of effector systems that trigger each other in a sequential hierarchy, terminating with the expulsion of gastric contents.2 An alternative model is proposed in this chapter.
Disorders of brain structure and function and crime
Published in John C. Gunn, Pamela J. Taylor, Forensic Psychiatry, 2014
Pamela J Taylor, John Gunnm, Michael D Kopelman, Veena Kumari, Pamela J Taylor, Birgit Völlm, Mairead Dolan, Paul d‘Orban, John Gunn, Anthony Holland, Michael D Kopelman, Graham Robertson, Pamela J Taylor
It is now recognized that the prefrontal cortex is involved in planning, organizing and forming strategy and integrating working memory and attention in order to form, collectively, the higher executive cognitive functions (Miller and Cohen, 2001). Its ventrolateral part is considered specific for the processes governing impulse control and behavioural inhibition (Sakagami et al., 2006; Sakagami and Pan, 2007). The prefrontal cortex also has strong connections to the limbic regions and, together with the limbic system, forms a complex circuit that has been implicated in various aspects of emotion, affective style and emotion regulation (Phillips et al., 2003). Dysfunctions within this circuit are considered to constitute the neural substrates of violence (Davidson et al., 2000).
Is the Motor Cortex Only an Executive Area? Its Role in Motor Cognition
Published in Alexa Riehle, Eilon Vaadia, Motor Cortex in Voluntary Movements, 2004
The simulation hypothesis is a rather broad framework accounting for the relationship of mental phenomena to the activity of the neural substrate. Its empirical basis accumulated from experiments in cognitive neuroscience in the past two decades. One of the most influential results showed that visual mental images rely on activation of the early stages of information processing of the visual system. The primary visual cortex (V1) is consistently involved in visual mental imagery,5253 with an additional selective involvement of the inferotemporal cortex during imagery of visual objects and of the occipitoparietal cortex in visual spatial imagery. The explanation put forward for an activation of low-level processing areas during a high-level cognitive activity is that activation of topographically organized areas, such as V1, is needed for replacing the image within a spatial frame of reference. Higher-order areas, because they lack topographical organization, would not be able, by themselves, to achieve this task. In other words, the processing of visual imagery would have to follow the same processing track as visual perception for giving an image its spatial layout, a process that requires the participation of V1.
Vertical One-and-a-Half Syndrome with Pseudoabducens Palsy and Midbrain Horizontal Gaze Paresis
Published in Journal of Binocular Vision and Ocular Motility, 2022
Yasser Aladdin, Bader Shirah, Khurshid Khan
Various neural networks influence the vertical, horizontal, and torsional control of ocular motility through shared supranuclear, internuclear, and infranuclear projections within the mesencephalic tegmentum.1 Midbrain lesions may result in horizontal gaze palsy with contralateral saccadic failure due to interruption of the supranuclear corticofugal from frontal eye field and colliculofugal from superior colliculus pathways controlling horizontal gaze.1,2 Smooth pursuit might be spared in ventral tegmental mesencephalic lesions as the fibers subserving both horizontal and vertical smooth pursuit descend within the posterior cerebral peduncles.3 In this article, we report a rare case of a patient who sustained combined vertical and horizontal gaze deficits after a single infarct involving the mesodiencephalic junction. The neural substrate for each deficit is briefly discussed in light of clinical findings.
Noradrenergic enhancement of object recognition and object location memory in mice
Published in Stress, 2021
Qi Song, Youri G. Bolsius, Giacomo Ronzoni, Marloes J. A. G. Henckens, Benno Roozendaal
In the present study, we investigated the effect of posttraining noradrenergic activation in male C57BL/6J mice on object recognition memory (ORM) and object location memory (OLM) (Leger et al., 2013; Roozendaal et al., 2010; Vogel-Ciernia & Wood, 2014). Several findings suggest that memory performance in these two tasks is supported by distinct neural substrates. (Balderas et al., 2008; Barker & Warburton, 2011), memory for the location on an object relies on the hippocampus (Balderas et al., 2008). Standard ORM and OLM have been successfully tested using mice (Vogel-Ciernia & Wood, 2014), but the effect of posttraining noradrenergic activation in mice on ORM and OLM has not yet been investigated. Here we found that, similar to rats, systemic posttraining injection of yohimbine, a noradrenergic stimulant which increases noradrenergic signaling (Nirogi et al., 2012; Szemeredi et al., 1991), induces dose-dependent enhancement of memory consolidation on both the ORM and OLM tasks. These findings thus pave the way for a systematic investigation of the neural circuitry underlying emotional arousal effects on memory.
Brain Surrogates—Empty or Full Makes the Difference
Published in The American Journal of Bioethics, 2021
In other words, “consciousness” is too ill-defined to be useful as a benchmark in determining the brain-likeness of brain surrogates. I suggest to use another feature instead, namely memory, as something that is specific for nervous systems and for which there is biological evidence, the mechanism of it can be rationally explained, and it is measurable. In a nutshell: neural systems can encode sensory input in so-called “engrams” at the level of neurons and synapses. Engrams are considered the basic units of memory. This means that memories have a biological (biophysical and biochemical) neural substrate (Josselyn and Tonegawa 2020). In laboratory experiments, it was demonstrated that in the intact live animal retrievable memories can even be artificially formed without sensory perception through direct optogenetic stimulation of brain areas (Vetere 2019).