Verbal Amnesia Secondary to Unilateral Infarct of the Mediodorsal Thalamic Nucleus.

INTRODUCTION: The mediodorsal nucleus is a subcomponent of the thalamus hypothesized to have a role in memory pathways. Given the limited number of reported cases and associated images, its clinical significance has not yet been fully elucidated. CASE PRESENTATION: We report the case of a 53-year-old man who presented with verbal amnesia, including deficits of both recall and recognition. High-resolution magnetic resonance imaging demonstrated a well-defined infarct contained within the mediodorsal nucleus. DISCUSSION: Current literature reports a range of conclusions regarding the extent to which the mediodorsal nucleus is involved in memory pathways. Several case series have attempted to localize infarcts by combining neuropsychology testing with imaging but were constrained by dated imaging modalities often dispersed with impurities. CONCLUSION: Our case demonstrates that isolated lesions of the mediodorsal nucleus can lead to deficits in both recall and recognition and that high-resolution magnetic resonance imaging is necessary when a thalamic infarct is suspected.

Confabulation, amnesia and motor memory loss as a presentation of apparent ITPR1 antibody autoimmune encephalitis.

A 59-year-old woman presented to the hospital with acute, hypoactive altered mental status. Her symptoms had begun 3 days prior when she developed hallucinations, urinary and faecal incontinence, and somnolence. She also exhibited confabulations, amnesia, motor memory loss and a wide-based gait. Medical, psychiatric and neurological evaluations including imaging and laboratory workup were unrevealing. Treatment for possible Wernicke encephalopathy and psychosis with high-dose intravenous thiamine and antipsychotic medications did not lead to improvement. After discharge, a send-out cerebrospinal fluid autoimmune encephalitis panel resulted positive for the newly identified neuronal inositol triphosphate receptor one (ITPR1) antibody. This prompted readmission for intravenous steroids, plasmapheresis and intravenous immunoglobulin, which yielded mild clinical improvement. Here, we describe confabulations and psychiatric symptoms as novel manifestations of the primary presentation of anti-ITPR1 encephalitis in an effort to promote faster recognition of this disease and early initiation of treatment in suspected cases.

Posthypnotic Amnesia in Hypnotizability Assessment: Validation of a New Scoring System for the Hypnotic Induction Profile.

The Hypnotic Induction Profile (HIP) is a standardized assessment of hypnotizability featuring a validated 0-10 scoring system, that does not factor in posthypnotic amnesia. Using confirmatory factor analyses (CFA), we compared the 10-point scoring system with a new 12-point system that includes the posthypnotic amnesia item in independent samples of individuals with fibromyalgia (n = 98) and healthy adults (n = 97). Additionally, we explored associations of the two scoring systems with measures of hypnotic phenomena. CFA results indicate that the 12-point scoring system is a good fit for the 1-factor model of hypnotizability. Posthypnotic amnesia loaded highly on the model in the fibromyalgia sample, and moderately on the model in healthy adults. Furthermore, the 12-point scoring system correlated significantly with measures of hypnotic phenomena. We conclude that the 12-point scoring system is psychometrically equivalent yet conceptually more comprehensive than the 10-point scoring system.

Electroacupuncture reduces scopolamine-induced amnesia via mediating the miR-210/SIN3A and miR-183/SIN3A signaling pathway.

BACKGROUND: The expression of SIN3A is closely correlated with electroacupuncture (EA) treatment efficacy of scopolamine-induced amnesia (SIA), but its underlying mechanisms remain to be further explored. METHODS: Quantitative real-time PCR was performed to analyze the expression of candidate microRNAs (miRNAs) and SIN3A mRNA in a rat model of SIA. Western blot was carried out to evaluate the differential expression of SIN3A proteins under different circumstances. Luciferase assay was used to explore the inhibitory role of certain miRNAs in SIN3A expression. A novel object recognition (NOR) test was performed to assess the memory function of SIA rats undergoing EA treatment. Immunohistochemistry was carried out to evaluate the expression of SIN3A in the hippocampus of SIA rats. RESULTS: Rno-miR-183-5p, rno-miR-34c-3p and rno-miR-210-3p were significantly up-regulated in SIA rats treated with EA. In addition, rno-miR-183-5p and rno-miR-210-3p exerted an inhibitory effect on SIN3A expression. EA treatment of SIA rats effectively restored the dysregulated expression of rno-miR-183-5p, rno-miR-210-3p and SIN3A. EA treatment also promoted the inhibited expression of neuronal IEGs including Arc, Egr1, Homer1 and Narp in the hippocampus of SIA rats. Accordingly, the NOR test also confirmed the effect of EA treatment on the improvement of memory in SIA rats. CONCLUSION: In summary, the findings of this study demonstrated that scopolamine-induced amnesia was associated with downregulated expression of miR-210/miR-183 and upregulated expression of SIN3A. Furthermore, treatment with EA alleviated scopolamine-induced amnesia in rats and was associated with upregulated expression of miR-210/miR-183 and downregulated expression of SIN3A.

Ameliorating Activity of Ishige okamurae on the Amyloid Beta-Induced Cognitive Deficits and Neurotoxicity through Regulating ERK, p38 MAPK, and JNK Signaling in Alzheimer's Disease-Like Mice Model.

SCOPE: Alzheimer's disease (AD) is associated with amyloid beta peptide (Aß25-35 ) accumulation in brains, which induces neurotoxicity and cognitive impairment. The effects of Ishige okamurae, an edible brown algae, on Aß25-35 -induced cognitive impairment and neuronal toxicity is investigated. The aim of this study is to determine the molecular mechanisms responsible for I. okamurae extracts (IOE) mediating anti-AD effects. METHODS AND RESULTS: Oral administration of IOE significantly attenuated Aß25-35 -induced cognitive deficits, as estimated by Y-maze and Morris water maze tests. IOE also attenuated the Aß25-35 -induced cellular apoptosis and expression of inducible isoforms of nitric oxide synthases (iNOS) and cyclooxygenase-2 (COX-2) in mouse brains and PC12 cells. In addition, Aß25-35 -induced phosphorylation of ERK, p38 MAPK, and JNK in mouse brains and PC12 cells is significantly abolished by administration of IOE. In PC12 cells, pretreatment of signal inhibitors (PD98059 (MEK inhibitor), SB203580 (p38 MAPK inhibitor), and SP600125 (JNK inhibitor)) recovers Aß25-35 -mediated cellular dysregulations to the same extent as does IOE pretreatment. CONCLUSION: Taken together, the data suggest that Aß25-35 -induced AD progress may be attenuated by administration of IOE through prevention of Aß25-35 -induced phosphorylation of ERK, p38 MAPK, and JNK.

[Pure Amnesia].

Pure amnesia (amnesic syndrome) is an organic brain syndrome characterized by impairment in episodic memory, with either an anterograde or sometimes retrograde loss of memories. Although episodic memory is impaired, semantic memory, immediate memory, and procedural memory are preserved. The Papez circuit is a network of nerve fibers and nerve centers that starts and ends in the hippocampus travelling by way of the fornix, mammillary bodies, anterior thalamic nuclei, cingulate gyrus, and parahippocampal gyrus. A lesion restricted to this circuit often produces pure amnesia. Regions concerned with the Yakovlev circuit also have an important role in memory. Clinical cases of pure amnesia caused by cerebrovascular disease presented following brain imaging and resulted from various different lesions. The cases identified were predominantly thalamic amnesia and hippocampal amnesia. Thalamic amnesia often resulted from an infarction in the territory of the thalamotuberal artery and paramedian thalamic artery although thalamic hemorrhage in medial portion of thalamus also produced pure amnesia. Hippocampal amnesia usually occurred following an infarction in the temporal branches of posterior cerebral artery. Cases of retrosplenial amnesia caused by subcortical hematoma and infarction in the retrosplenial region are also described. In addition, cases of pure amnesia resulting from an infarction in the fornix, mammillary body hemorrhage, and caudate hemorrhage are also shown.

Trachyspermum ammi Seeds Supplementation Helps Reverse Scopolamine, Alprazolam and Electroshock Induced Amnesia.

The present study was designed to explore the beneficial effects of successive 10 days administration of Trachyspermum ammi seed's powder (TASP) along with diet (at the dose of 0.5%, 1.0% and 2.0% w/w) on learning and memory of mice. A total of 306 mice divided in 51 equal groups were employed in the study. Passive avoidance paradigm (PAP) and Object recognition Task (ORT) were employed as exteroceptive models. The brain acetylcholinesterase activity (AChE), serum cholesterol, brain monoaldehyde (MDA), brain reduced glutathione (GSH) and brain nitrite were estimated and Alprazolam, Scopolamine and Electroshock induced amnesia was employed to describe the actions. Treatment of TASP significantly increased step down latency of PAA and significantly increased discrimination index of ORT in groups with or without amnesia when compared to respective control groups. Furthermore, TASP administration resulted in significant fall in brain AChE activity, brain MDA level and brain nitrite level with simultaneous rise in brain GSH level, thereby decreased oxidative damage. A significant decrease in serum cholesterol was also observed. Ajowan supplementation may prove a remedy for the management of cognitive disorders owing to have pro-cholinergic, antioxidant and hypo-lipidemic activities.

Thalamic amnesia after infarct: The role of the mammillothalamic tract and mediodorsal nucleus.

OBJECTIVE: To improve current understanding of the mechanisms behind thalamic amnesia, as it is unclear whether it is directly related to damage to specific nuclei, in particular to the anterior or mediodorsal nuclei, or indirectly related to lesions of the mammillothalamic tract (MTT). METHODS: We recruited 12 patients with a left thalamic infarction and 25 healthy matched controls. All underwent a comprehensive neuropsychological assessment of verbal and visual memory, executive functions, language, and affect, and a high-resolution structural volumetric MRI scan. Thalamic lesions were manually segmented and automatically localized with a computerized thalamic atlas. As well as comparing patients with controls, we divided patients into subgroups with intact or damaged MTT. RESULTS: Only one patient had a small lesion of the anterior nucleus. Most of the lesions included the mediodorsal (n = 11) and intralaminar nuclei (n = 12). Patients performed worse than controls on the verbal memory tasks, but the 5 patients with intact MTT who showed isolated lesions of the mediodorsal nucleus (MD) only displayed moderate memory impairment. The 7 patients with a damaged MTT performed worse on the verbal memory tasks than those whose MTT was intact. CONCLUSIONS: Lesions in the MTT and in the MD result in memory impairment, severely in the case of MTT and to a lesser extent in the case of MD, thus highlighting the roles played by these 2 structures in memory circuits.

The art of providing anaesthesia in Greek mythology.

We endeavored to thoroughly review Greek mythology and collect tales dealing with anaesthesia and myochalasis (paralysis). Among the evaluated sources were the poems of Hesiod, the epics of Homer, the tragedies of the great Athenian poets (namely Aeschylus, Sophocles and Euripides) as well as the contributions of several Latin writers, including Ovid. We found several examples of achieving hypnosis, analgesia and amnesia through the administration of drugs (inhaled or not) and music. Adverse events of drugs used for this purpose, such as post-anaesthetic emergence delirium, hallucinations, respiratory arrest and penis erection, were described in the presented myths. We noted that providing sleep was considered a divine privilege, although several mortals (mainly women) exhibited such powers as well. The concepts of sleep and death were closely associated in ancient classical thought. This review may stimulate anaesthetists' fantasy and may help them realise the nobility of their medical specialty.

Bilateral supratentorial epidural hematomas: a rare complication in adolescent spine surgery.

A 14-year-old girl presented with a rare case of spontaneous bilateral supratentorial epidural hematomas which developed rapidly following cervical surgery. The hematomas presumably resulted from dural dynamics changes secondary to cerebrospinal fluid loss and intracranial hypotension. Intracranial epidural hemorrhage after spinal surgery is extremely uncommon with only one previous case report. Spontaneous intracranial epidural hematoma is an extremely rare complication, but should be considered as a possible complication of spine surgery, especially in adolescents complicated by delayed consciousness and breathing restoration from anesthesia. This case report expands the presently known clinical spectrum of this uncommon complication.

[Acute amnestic syndrome: left thalamo-polar infarct]. / Syndrome amnésique aigu: AVC thalamo-polaire gauche.

An 80-year old American patient was found wandering in a mountain village of Switzerland, with an anterograde, prospective, retrograde, dyschronologic amnesic syndrome without confabulation, paramnesia or false recognitions, disoriented, slightly confused, with no focal sensory, motor, ataxic or visual field deficit, with a mild dysexecutive syndrome. The MR imaging showed an acute thalamo-polar artery infarct. A dysconnection of the mamillo-othalamic and thalamo-temporal pathways is felt at the origin of the amnesic syndrome. A brief review of the other presentation of this chamelon syndrome is presented, together the main etiologies at its origin.

Evaluation of the evidence for the trauma and fantasy models of dissociation.

The relationship between a reported history of trauma and dissociative symptoms has been explained in 2 conflicting ways. Pathological dissociation has been conceptualized as a response to antecedent traumatic stress and/or severe psychological adversity. Others have proposed that dissociation makes individuals prone to fantasy, thereby engendering confabulated memories of trauma. We examine data related to a series of 8 contrasting predictions based on the trauma model and the fantasy model of dissociation. In keeping with the trauma model, the relationship between trauma and dissociation was consistent and moderate in strength, and remained significant when objective measures of trauma were used. Dissociation was temporally related to trauma and trauma treatment, and was predictive of trauma history when fantasy proneness was controlled. Dissociation was not reliably associated with suggestibility, nor was there evidence for the fantasy model prediction of greater inaccuracy of recovered memory. Instead, dissociation was positively related to a history of trauma memory recovery and negatively related to the more general measures of narrative cohesion. Research also supports the trauma theory of dissociation as a regulatory response to fear or other extreme emotion with measurable biological correlates. We conclude, on the basis of evidence related to these 8 predictions, that there is strong empirical support for the hypothesis that trauma causes dissociation, and that dissociation remains related to trauma history when fantasy proneness is controlled. We find little support for the hypothesis that the dissociation-trauma relationship is due to fantasy proneness or confabulated memories of trauma.

Doing better by getting worse: posthypnotic amnesia improves random number generation.

Although forgetting is often regarded as a deficit that we need to control to optimize cognitive functioning, it can have beneficial effects in a number of contexts. We examined whether disrupting memory for previous numerical responses would attenuate repetition avoidance (the tendency to avoid repeating the same number) during random number generation and thereby improve the randomness of responses. Low suggestible and low dissociative and high dissociative highly suggestible individuals completed a random number generation task in a control condition, following a posthypnotic amnesia suggestion to forget previous numerical responses, and in a second control condition following the cancellation of the suggestion. High dissociative highly suggestible participants displayed a selective increase in repetitions during posthypnotic amnesia, with equivalent repetition frequency to a random system, whereas the other two groups exhibited repetition avoidance across conditions. Our results demonstrate that temporarily disrupting memory for previous numerical responses improves random number generation.

A voxel-based analysis of FDG-PET in traumatic brain injury: regional metabolism and relationship between the thalamus and cortical areas.

The objective was to study the correlations and the differences in glucose metabolism between the thalamus and cortical structures in a sample of severe traumatic brain injury (TBI) patients with different neurological outcomes. We studied 49 patients who had suffered a severe TBI and 10 healthy control subjects using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET). The patients were divided into three groups: a vegetative or minimally-conscious state (MCS&VS) group (n=17), which included patients who were in a vegetative or a minimally conscious state; an In-post-traumatic amnesia (In-PTA) group (n=12), which included patients in PTA; and an Out-PTA group (n=20), which included patients who had recovered from PTA. SPM5 software was used to determine the metabolic differences between the groups. FDG-PET images were normalized and four regions of interest were generated around the thalamus, precuneus, and the frontal and temporal lobes. The groups were parameterized using Student's t-test. Principal component analysis was used to obtain an intensity-estimated-value per subject to correlate the function between the structures. Differences in glucose metabolism in all structures were related to the neurological outcome, and the most severe patients showed the most severe hypometabolism. We also found a significant correlation between the cortico-thalamo-cortical metabolism in all groups. Voxel-based analysis suggests a functional correlation between these four areas, and decreased metabolism was associated with less favorable outcomes. Higher levels of activation of the cortico-cortical connections appear to be related to better neurological condition. Differences in the thalamo-cortical correlations between patients and controls may be related to traumatic dysfunction due to focal or diffuse lesions.

Inflammation after trauma: microglial activation and traumatic brain injury.

OBJECTIVE: Patient outcome after traumatic brain injury (TBI) is highly variable. The underlying pathophysiology of this is poorly understood, but inflammation is potentially an important factor. Microglia orchestrate many aspects of this response. Their activation can be studied in vivo using the positron emission tomography (PET) ligand [11C](R)PK11195 (PK). In this study, we investigate whether an inflammatory response to TBI persists, and whether this response relates to structural brain abnormalities and cognitive function. METHODS: Ten patients, studied at least 11 months after moderate to severe TBI, underwent PK PET and structural magnetic resonance imaging (including diffusion tensor imaging). PK binding potentials were calculated in and around the site of focal brain damage, and in selected distant and subcortical brain regions. Standardized neuropsychological tests were administered. RESULTS: PK binding was significantly raised in the thalami, putamen, occipital cortices, and posterior limb of the internal capsules after TBI. There was no increase in PK binding at the original site of focal brain injury. High PK binding in the thalamus was associated with more severe cognitive impairment, although binding was not correlated with either the time since the injury or the extent of structural brain damage. INTERPRETATION: We demonstrate that increased microglial activation can be present up to 17 years after TBI. This suggests that TBI triggers a chronic inflammatory response particularly in subcortical regions. This highlights the importance of considering the response to TBI as evolving over time and suggests interventions may be beneficial for longer intervals after trauma than previously assumed.

Default mode network disruption secondary to a lesion in the anterior thalamus.

OBJECTIVE: To describe the neuroanatomical correlations of an isolated lesion in the anterior thalamus using functional imaging in a 40-year-old man with multiple sclerosis. DESIGN: Case report with 10 cognitively normal controls. SETTING: Mayo Clinic, Rochester, Minnesota. PATIENT: A 40-year-old man with a 2-week course of acute-onset amnesia, abulia, poor concentration, hypersomnolence, and reclusiveness. INTERVENTION: Functional magnetic resonance imaging. RESULTS: Magnetic resonance imaging demonstrated a large gadolinium-enhancing plaque in the left anterior thalamus and other demyelinating plaques in the subcortical and periventricular white matter, consistent with the diagnosis of multiple sclerosis. His symptoms persisted at the 7-month follow-up. The patient's resting state functional magnetic resonance image demonstrated an asymmetric disruption of the posterior cingulate portion of the default mode network ipsilateral to the left thalamic lesion. CONCLUSIONS: A large multiple sclerosis plaque in the deep gray matter altered the resting state functional connectivity in a patient presenting with pure cognitive dysfunction. Such altered connectivity may underlie cognitive symptoms in neurologic disease. In addition, this case provides lesional evidence of default mode network circuitry involving the pathways of the circuit of Papez.

Mental time in amnesia: evidence from bilateral medial temporal damage before and after recovery.

The human mind is continuously involved in "projecting" the self in time in order to process past memories and predict future occurrences. "Self-projection" in time involves episodic and spatial memory, relying on medial-temporal structures, but also engages visuo-spatial imagery, relying on occipito-temporal structures, and self-location, relying on temporo-parietal structures. Here we had the rare opportunity to investigate the relation between self-projection in time and memory, using a novel behavioural paradigm, in a patient with subacute bilateral medial-temporal damage during a period of amnesia as well as after recovery. Despite her memory deficit the patient was able to "project" herself to past and future, yet with significant improvement after recovery. We discuss our findings with respect to the relations between episodic memory and medial-temporal structures with self-projection in time to past and future.

Neuro-Behcet's disease presenting with amnesia and frontal dysfunction.

We report a 48-year-old patient with neuro-Behcet's disease who presented with the combination of severe memory impairment and frontal/executive dysfunction. The clinical feature mimicked that of diencephalic amnesic syndrome. The MRI and SPECT findings supported the notion that the thalamus and related subcortical-frontal connection was responsible for this patient's problem.