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Hippocampus Nov 2014We often engage in counterfactual (CF) thinking, which involves reflecting on "what might have been." Creating alternative versions of reality seems to have parallels...
We often engage in counterfactual (CF) thinking, which involves reflecting on "what might have been." Creating alternative versions of reality seems to have parallels with recollecting the past and imagining the future in requiring the simulation of internally generated models of complex events. Given that episodic memory and imagining the future are impaired in patients with hippocampal damage and amnesia, we wondered whether successful CF thinking also depends upon the integrity of the hippocampus. Here using two nonepisodic CF thinking tasks, we found that patients with bilateral hippocampal damage and amnesia performed comparably with matched controls. They could deconstruct reality, add in and recombine elements, change relations between temporal sequences of events, enabling them to determine plausible alternatives of complex episodes. A difference between the patients and control participants was evident, however, in the patients' subtle avoidance of CF simulations that required the construction of an internal spatial representation. Overall, our findings suggest that mental simulation in the form of nonepisodic CF thinking does not seem to depend upon the hippocampus unless there is the added requirement for construction of a coherent spatial scene within which to play out scenarios.
Topics: Adult; Amnesia; Female; Hippocampus; Humans; Imagination; Male; Mental Recall; Middle Aged; Narration; Neuropsychological Tests; Thinking
PubMed: 24978690
DOI: 10.1002/hipo.22323 -
Indian Journal of Pharmacology 2022Conyza bonariensis is an ornamental medicinal weed. This experiment was planned to explore the outcome of petroleum ether extract of C. bonariensis (PECB) leaves on...
OBJECTIVE
Conyza bonariensis is an ornamental medicinal weed. This experiment was planned to explore the outcome of petroleum ether extract of C. bonariensis (PECB) leaves on scopolamine-induced amnesia in rats.
MATERIALS AND METHODS
For impairing memory, 0.4 mg/kg (i. p.) of scopolamine was given. Fifty to 200 mg/kg of PECB was fed orally to rats and 3 mg/kg (i. p.) of tacrine was given as a standard drug. Anti-amnesic property was evaluated in Barnes maze using ANY-maze software. Following a behavioral study, acetylcholinesterase (AChE), β-amyloid, antioxidant enzymes, and cytokine levels were measured. Furthermore, reverse transcription-polymerase chain reaction was done for expression of the marker genes such as AChE, Nrf2, NF-κB, PP2A, and HO-1, whereas BDNF, TrkB, caspase-3, and Bax were measured by Western blotting.
RESULTS
PECB and tacrine significantly improved memory dysfunction by decreasing escape latency in Barnes maze. At the highest dose, treatment with PECB altered the scopolamine-induced hyperactivation of AChE and β-amyloid activity. PECB elevated the levels of superoxide dismutase, glutathione, and catalase and decreased lipid peroxidation and nitric oxide dose dependently. PECB attenuated scopolamine-induced increase of tumor necrosis factor-α and interleukin (IL)-1β concentrations in the hippocampus with reversed diminished IL-10 level toward normal in the brain. Nrf2, HO-1, PP2A, BDNF, and TrkB were significantly upregulated with downregulation of AChE, NF-κB, Tau, Bax, and caspase-3. Different components such as beta-amyrin and alpha-amyrin were isolated from leaves of the plant.
CONCLUSION
The results indicated that PECB might be a potential curative drug for the treatment of cognitive impairment.
Topics: Acetylcholinesterase; Amnesia; Animals; Antioxidants; Brain-Derived Neurotrophic Factor; Caspase 3; Conyza; Maze Learning; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Plant Extracts; Rats; Scopolamine; Tacrine; bcl-2-Associated X Protein
PubMed: 35546461
DOI: 10.4103/ijp.ijp_201_19 -
Experimental Brain Research Aug 2023Is retrograde amnesia associated with an ability to know who we are and imagine what we will be like in the future? To answer this question, we had S.G., a patient with...
Is retrograde amnesia associated with an ability to know who we are and imagine what we will be like in the future? To answer this question, we had S.G., a patient with focal retrograde amnesia following hypoxia, two brain-damaged (control) patients with no retrograde memory deficits, and healthy controls judge whether each of a series of trait adjectives was descriptive of their present self, future self, another person, and that person in the future, and later recognize studied traits among distractors. Healthy controls and control patients were more accurate in recognizing self-related compared to other-related traits, a phenomenon known as the self-reference effect (SRE). This held for both present and future self-views. By contrast, no evidence of (present or future) SRE was observed in SG, who concomitantly showed reduced certainty about his personality traits. These findings indicate that retrograde amnesia can weaken the self-schema and preclude its instantiation during self-related processing.
Topics: Humans; Amnesia, Retrograde; Memory Disorders; Brain Injuries; Language; Neuropsychological Tests
PubMed: 37450003
DOI: 10.1007/s00221-023-06661-2 -
Neurology(R) Neuroimmunology &... Jul 2021To report an unusual clinical phenotype of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis and describe associated neuropathologic...
OBJECTIVE
To report an unusual clinical phenotype of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis and describe associated neuropathologic findings.
METHODS
We retrospectively investigated 3 AMPAR encephalitis patients with autoimmune global hippocampal amnesia using comprehensive cognitive and neuropsychologic assessment, antibody testing by in-house tissue-based and cell-based assays, and neuropathologic analysis of brain autopsy tissue including histology and immunohistochemistry.
RESULTS
Three patients presented with acute-to-subacute global amnesia without affection of cognitive performance, attention, concentration, or verbal function. None of the patients had epileptic seizures, change of behavior, personality changes, or psychiatric symptoms. The MRI was normal in 1 patient and showed increased fluid-attenuated inversion recovery/T2 signal in the hippocampus in the other 2 patients. Two patients showed complete remission after immunotherapy. The one patient who did not improve had an underlying adenocarcinoma of the lung and died 3.5 months after disease onset because of tumor progression. Neuropathologic analysis of the brain autopsy revealed unilateral hippocampal sclerosis accompanied by mild inflammatory infiltrates, predominantly composed of T lymphocytes, and decrease of AMPAR immunoreactivity.
CONCLUSION
AMPAR antibodies usually associate with limbic encephalitis but may also present with immune responsive, acute-to-subacute, isolated hippocampal dysfunction without overt inflammatory CSF or MRI changes.
Topics: Adult; Aged; Amnesia; Autoantibodies; Autoimmune Diseases of the Nervous System; Encephalitis; Female; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Receptors, AMPA; Retrospective Studies
PubMed: 34016735
DOI: 10.1212/NXI.0000000000001019 -
Alcohol-Induced Amnesia and Personalized Drinking Feedback: Blackouts Predict Intervention Response.Behavior Therapy Jan 2019Alcohol-induced amnesia ("blackout") is a reliable predictor of alcohol-related harm. Given its association with other negative consequences, experience of... (Randomized Controlled Trial)
Randomized Controlled Trial
Alcohol-induced amnesia ("blackout") is a reliable predictor of alcohol-related harm. Given its association with other negative consequences, experience of alcohol-induced amnesia may serve as a teachable moment, after which individuals are more likely to respond to intervention. To test this hypothesis, alcohol-induced amnesia was evaluated as a moderator of brief intervention effect on (a) alcohol-related consequences and (b) the proposed intervention mediators, protective behavioral strategies and peak blood alcohol concentration (BAC). Baseline alcohol risk measured using the Alcohol Use Disorders Identification Test (AUDIT) was also evaluated as a moderator to rule out the possibility that amnesia is simply an indicator of more general alcohol risk. College students (N = 198) reporting alcohol use in a typical week completed assessments at baseline and 1-month follow-up as part of a larger intervention trial. Participants were randomized to assessment only (AO; n = 58) or personalized feedback intervention (PFI; n = 140). Hierarchical regression was used to examine direct and indirect intervention effects. A significant group-by-amnesia interaction revealed that only PFI participants who had experienced alcohol-induced amnesia in the past month reported decreases in alcohol consequences at 1-month follow-up. The PFI reduced alcohol-related consequences indirectly through changes in peak BAC, but only among those who had experienced amnesia at baseline. In contrast, baseline alcohol risk (AUDIT) did not moderate intervention effects, and use of protective behavioral strategies did not statistically mediate intervention effects. Findings suggest that loss of memory for drinking events is a unique determinant of young adult response to brief alcohol intervention. Normative feedback interventions may be particularly effective for individuals who have experienced alcohol-induced amnesia in the past 30 days.
Topics: Adolescent; Alcohol Drinking; Amnesia; Blood Alcohol Content; Counseling; Early Medical Intervention; Feedback, Psychological; Female; Follow-Up Studies; Forecasting; Humans; Male; Students; Young Adult
PubMed: 30661564
DOI: 10.1016/j.beth.2018.03.008 -
Behavioural Brain Research Sep 2019Contextual fear conditioning relies upon a network of cortical and subcortical structures, including the hippocampus and the retrosplenial cortex (RSC). However, the...
Contextual fear conditioning relies upon a network of cortical and subcortical structures, including the hippocampus and the retrosplenial cortex (RSC). However, the contribution of the hippocampus is parameter-dependent. For example, with "weak" training procedures, lesions of the hippocampus produce both retrograde and anterograde context amnesia. However, with "strong" training procedures (e.g., more trials and/or higher levels of footshock), lesions of the hippocampus produce retrograde context amnesia but not anterograde amnesia (Wiltgen et al., 2006). Likewise, prior studies have shown that with weak training, RSC lesions produce both retrograde and anterograde context amnesia (Keene & Bucci, 2008). The purpose of the current study was to examine the effects of RSC damage on contextual fear conditioning following strong training. In Experiment 1, lesions of the RSC resulted in both retrograde and anterograde context amnesia following strong training using the same unsignaled fear conditioning procedures described by Wiltgen et al. (2006). In Experiment 2, using a signaled fear conditioning procedure, we replicated these effects on context memory observing both retrograde and anterograde context amnesia. In contrast, there were no lesion effects on tone-fear memory. Thus, unlike lesions of the hippocampus, lesions of RSC produce both retrograde and anterograde context amnesia even when rats undergo strong fear conditioning. These findings suggest that the RSC has an essential role in contextual fear conditioning and that other systems or pathways are unable to compensate for the loss of RSC function.
Topics: Amnesia, Anterograde; Amnesia, Retrograde; Animals; Association Learning; Auditory Perception; Conditioning, Psychological; Electroshock; Fear; Gyrus Cinguli; Hippocampus; Male; Memory; Rats, Long-Evans
PubMed: 31039379
DOI: 10.1016/j.bbr.2019.111920 -
Neuropsychology Nov 2017To provide a select review of our applications of quantitative modeling to highlight the utility of such approaches to better understand the neuropsychological deficits... (Review)
Review
OBJECTIVE
To provide a select review of our applications of quantitative modeling to highlight the utility of such approaches to better understand the neuropsychological deficits associated with various neurologic and psychiatric diseases.
METHOD
We review our work examining category learning in various patient populations, including individuals with basal ganglia disorders (Huntington's Disease and Parkinson's disease), amnesia and Eating Disorders.
RESULTS
Our review suggests that the use of quantitative models has enabled a better understanding of the learning deficits often observed in these conditions and has allowed us to form novel hypotheses about the neurobiological bases of their deficits.
CONCLUSIONS
We feel that the use of neurobiologically inspired quantitative modeling holds great promise in neuropsychological assessment and that future clinical measures should incorporate the use of such models as part of their standard scoring. Appropriate studies need to be completed, however, to determine whether such modeling techniques adhere to the rigorous psychometric properties necessary for a valid and reliable application in a clinical setting. (PsycINFO Database Record
Topics: Amnesia; Cognition; Feeding and Eating Disorders; Humans; Huntington Disease; Learning; Learning Disabilities; Models, Psychological; Models, Statistical; Neuropsychological Tests; Parkinson Disease
PubMed: 29376668
DOI: 10.1037/neu0000422 -
Neuropsychologia Aug 2018During conversation, people integrate information from co-speech hand gestures with information in spoken language. For example, after hearing the sentence, "A piece of...
During conversation, people integrate information from co-speech hand gestures with information in spoken language. For example, after hearing the sentence, "A piece of the log flew up and hit Carl in the face" while viewing a gesture directed at the nose, people tend to later report that the log hit Carl in the nose (information only in gesture) rather than in the face (information in speech). The cognitive and neural mechanisms that support the integration of gesture with speech are unclear. One possibility is that the hippocampus - known for its role in relational memory and information integration - is necessary for integrating gesture and speech. To test this possibility, we examined how patients with hippocampal amnesia and healthy and brain-damaged comparison participants express information from gesture in a narrative retelling task. Participants watched videos of an experimenter telling narratives that included hand gestures that contained supplementary information. Participants were asked to retell the narratives and their spoken retellings were assessed for the presence of information from gesture. For features that had been accompanied by supplementary gesture, patients with amnesia retold fewer of these features overall and fewer retellings that matched the speech from the narrative. Yet their retellings included features that contained information that had been present uniquely in gesture in amounts that were not reliably different from comparison groups. Thus, a functioning hippocampus is not necessary for gesture-speech integration over short timescales. Providing unique information in gesture may enhance communication for individuals with declarative memory impairment, possibly via non-declarative memory mechanisms.
Topics: Acoustic Stimulation; Aged; Amnesia; Female; Gestures; Hippocampus; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; Psychomotor Performance; Speech
PubMed: 29932960
DOI: 10.1016/j.neuropsychologia.2018.06.012 -
Ugeskrift For Laeger Jun 2015Transient epileptic amnesia (TEA) is a presumably underdiagnosed syndrome belonging to the group of temporal lobe epilepsies. It can easily be misdiagnosed as transient...
Transient epileptic amnesia (TEA) is a presumably underdiagnosed syndrome belonging to the group of temporal lobe epilepsies. It can easily be misdiagnosed as transient global amnesia (TGA), transient ischaemic attack, psychogenic amnesia or even dementia. Many patients complain of loss of autobiographical memory and accelerated long-term forgetting. We present a case to emphasize both the importance of diagnosing TEA and the pitfalls between TEA and TGA syndrome.
Topics: Amnesia; Amnesia, Transient Global; Diagnosis, Differential; Epilepsy; Female; Humans; Magnetic Resonance Imaging; Middle Aged
PubMed: 26058440
DOI: No ID Found -
Neurology India 2020Transient global amnesia (TGA) is a temporary short-term reversible memory loss. Etiology of TGA remains unclear with various hypotheses. We analyzed clinical...
OBJECTIVES
Transient global amnesia (TGA) is a temporary short-term reversible memory loss. Etiology of TGA remains unclear with various hypotheses. We analyzed clinical characteristics, neuroimaging, and electrophysiological findings as well as comorbidities and seasonal variation in TGA patients with regard to possible background of the syndrome.
MATERIALS AND METHODS
A total of 56 patients (42 women and 14 men) with TGA hospitalized from 2008 to 2016 in the Department of Neurology, Wrocław Medical University.
RESULTS
A total of 52 patients (92.9%) underwent their first-ever episode of TGA. The potential triggers or events before episode could be recognized in 22 patients (39.3%). 35.7% patients had TGA in summer and 26.8% in winter months. In 92.9% patients chronic diseases were found, included: Hypertension (60.7%), dyslipidemia (48.2%), autoimmune thyroiditis (17.9%), and ischemic heart disease (14.3%). One patient (1,8%) suffered from migraine. Doppler ultrasonography of carotid arteries revealed abnormalities in 29 patients (51.8%). Electroencephalography abnormalities were observed in 10 (17.6%) of patients.
CONCLUSION
Our findings suggest a putative cerebrovascular background of transient global amnesia. No evidence has been provided for the association between TGA and epilepsy or migraine. Among comorbidities, autoimmune thyroiditis deserves further investigation with regard to its potential links with TGA.
Topics: Amnesia, Transient Global; Electroencephalography; Epilepsy; Female; Humans; Male; Migraine Disorders; Risk Factors
PubMed: 32643675
DOI: 10.4103/0028-3886.288979