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Paper 2
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
An 82 year old, unkempt woman who lives alone is admitted with acute confusion. On clinical examination she is noted to be ataxic. A CT head is unremarkable. MRI brain demonstrates bilateral high T2 and FLAIR signal within the mammillary bodies and medial thalami. Further high signal is seen within the pons. Following gadolinium administration there is enhancement of the mammillary bodies bilaterally.
The Limbic System
Published in Jay A. Goldstein, Chronic Fatigue Syndromes, 2020
The major structures of the limbic system are the hippocampus and the amygdala. Both are located in the medial part of the anterior temporal lobe, a region which is quite sensitive to anoxic damage and viral infection, notably by HSV-1. It is well accepted that the hippocampus is involved in the making of new memories, a process called “encoding.” Although the hippocampus has several input (afferent) systems, it has only one major output (efferent) system: the fornix. This structure, also part of the limbic system, terminates in the mammillary bodies, part of the hypothalamus. Thus the hip-pocampus can have a significant neuroendocrine-autonomic function as well as its better known roles in memory and emotion. It is divided into four areas (CA1-4) on the basis of histological and functional criteria. The CAl section is the most sensitive to hypoxic insult.
Neuroendocrine Morphology
Published in Paul V. Malven, Mammalian Neuroendocrinology, 2019
The following three tracts connect the hypothalamus with the midbrain and lower areas: mammillopeduncular tract (labeled H in Figure 2-3), mammillotegmental tract (G), dorsal longitudinal fasciculus (F). The mammillopeduncular tract and mammillotegmental tract both connect the mammillary bodies of the hypothalamus with the midbrain and lower regions. The hippocampus inputs into the hypothalamus pass by way of the fornix (E) to the preoptic area, arcuate nucleus and mammillary bodies of the hypothalamus. The thalamus connection with the mammillary bodies involves the mammillothalamic tract (I). The amygdala connections with the hypothalamus consist of (1) stria terminalis (C) which curves around in parallel with the fornix and (2) the shorter route from amygdala to hypothalamus called the direct amygdalohypothalamic tract (D). A major fiber tract passing through the hypothalamus is the medial forebrain bundle (B) which connects hypothalamus with the septum, rostral structures such as the olfactory gray, and structures caudal to the hypothalamus. The epithalamus sends input to the preoptic area of the hypothalamus via the stria medullaris (A).
No negative impact of word retraining on vocabulary use or clarity of communication in semantic dementia
Published in Neuropsychological Rehabilitation, 2023
Sharon A. Savage, Leonie F. Lampe, Lyndsey Nickels
While there are no current medical treatments for this condition, reviews of behavioural interventions – in the form of word retraining programmes – have consistently shown that word retrieval for trained items can be improved (Carthery-Goulart et al., 2013; Croot, 2018; Croot et al., 2009; Jokel et al., 2014). While sample sizes are small, given the rarity of the disease, this training effect has been replicated in more than 30 individual cases. The ability for relearning words appears to be supported by the relative health of posterior aspects of the episodic memory network (Ritchey et al., 2015). Post-mortem anatomical studies have shown relative preservation of volume in the body and tail of the hippocampus (85% preserved), and of neurons in other crucial memory relay structures, such as the mammillary bodies and posterior cingulate, throughout the course of the disease (Tan et al., 2014). In addition, the functioning of this network has been supported by behavioural studies which illustrate the ability for new verbal learning for people with semantic dementia (Jefferies et al., 2011).
Morphometric and Myelin Basic Protein Expression Changes in Arcuate Nucleus Kisspeptin Neurons Underlie Activation of Hypothalamic Pituitary Gonadal-axis in Monkeys (Macaca Mulatta) during the Breeding Season
Published in Endocrine Research, 2022
Hira Zubair, Shazia Shamas, Hamid Ullah, Ghulam Nabi, Tanzeel Huma, Rahim Ullah, Rashad Hussain, Muhammad Shahab
The three breeding season monkeys were euthanized in September, and the two non-breeding animals were euthanized in July. All experimental protocols were carried out according to the guidelines of the Research Ethics Committee of the Quaid-I Azam University, Pakistan. Before euthanization, blood samples were taken from all the animals, and their body weight was measured; testicular volume was assessed by measuring the length (l) and width (w) of both testes with digital vernier calipers and using the formula for an ellipsoid [volume = (πw2l/6)], as explained earlier.35 All animals were dissected during the daytime (10:00–12:00) to have uniform conditions for the study. Animals were deeply sedated with ketamine hydrochloride (Ketamax, Rotex Medica, Trittau, Germany; 15–20 mg/kg BW, im). Hairs were shaved off from the skull, and then skin and muscles were removed with the help of a scalpel. The skull bones were then cut using a sharp bone cutter. After opening the skull, animals were killed by administering Propofol (Gobbi, Nova SA, Argentina; 10–15 mg/kg BW, iv). The brain was carefully taken out of the cranium and immediately placed on a cold glass plate. The hypothalamic blocks were dissected out as described previously.36 Briefly, coronal cuts were made anterior to the optic chiasm, through the mammillary bodies. A parasagittal cut was made at approximately 4 mm distance, on either side of the midline. A final horizontal cut was made dorsal to the anterior commissure.
Thiamine and phosphate esters concentrations in whole blood and serum of patients with alcohol use disorder: a relation with cognitive deficits
Published in Nutritional Neuroscience, 2021
Laurent Coulbault, Ludivine Ritz, François Vabret, Coralie Lannuzel, Céline Boudehent, Marie Nowoczyn, Hélène Beaunieux, Anne Lise Pitel
Using magnetic resonance imagery, it has been shown that AUD patients with Korsakoff’s syndrome present brain structural abnormalities, such as shrinkage of the thalamus, mammillary bodies and hippocampus, these structures being involved in memory processes [22]. In rodent models of thiamine deficiency, an altered neurogenesis of hippocampus was also reported, potentially associated with deficit of spatial memory [23]. Structural changes in brain have also been found in experimental models of Wernicke’s encephalopathy, using pyrithiamine which acts as a competitive inhibitor of Thiamine Pyrophosphokinase, and limits the transport of thiamine across the blood brain barrier [24]. Pyrithiamine-induced thiamine deficiency (PTD) was associated with alteration of neurogenesis and cell proliferation in vulnerable areas, confirming the negative effect of TD on brain [25].