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The Primary Care Companion For CNS... May 2023
Topics: Humans; Suicide, Attempted; Charcoal; Amnesia
PubMed: 37146431
DOI: 10.4088/PCC.22cr03386 -
Optogenetic inactivation of the medial septum impairs long-term object recognition memory formation.Molecular Brain Jun 2022Theta is one of the most prominent extracellular synchronous oscillations in the mammalian brain. Hippocampal theta relies on an intact medial septum (MS) and has been...
Theta is one of the most prominent extracellular synchronous oscillations in the mammalian brain. Hippocampal theta relies on an intact medial septum (MS) and has been consistently recorded during the training phase of some learning paradigms, suggesting that it may be implicated in hippocampus-dependent long-term memory processing. Object recognition memory (ORM) allows animals to identify familiar items and is essential for remembering facts and events. In rodents, long-term ORM formation requires a functional hippocampus but the involvement of the MS in this process remains controversial. We found that training adult male Wistar rats in a long-term ORM-inducing learning task involving exposure to two different, but behaviorally equivalent novel stimuli objects increased hippocampal theta power, and that suppressing theta via optogenetic MS inactivation caused amnesia. Importantly, the amnesia was specific to the object the animals were exploring when the MS was inactivated. Taken together, our results indicate that the MS is necessary for long-term ORM formation and suggest that hippocampal theta activity is causally linked to this process.
Topics: Amnesia; Animals; Hippocampus; Male; Mammals; Memory, Long-Term; Optogenetics; Rats; Rats, Wistar; Theta Rhythm
PubMed: 35672792
DOI: 10.1186/s13041-022-00938-3 -
Neuropsychologia Feb 2021Recent findings point to a role for hippocampus in the moment-by-moment processing of language, including the use and generation of semantic features in certain...
Recent findings point to a role for hippocampus in the moment-by-moment processing of language, including the use and generation of semantic features in certain contexts. What role the hippocampus might play in the processing of semantic relations in spoken language comprehension, however, is unknown. Here we test patients with bilateral hippocampal damage and dense amnesia in order to examine the necessity of hippocampus for lexico-semantic mapping processes in spoken language understanding. In two visual-world eye-tracking experiments, we monitor eye movements to images that are semantically related to spoken words and sentences. We find no impairment in amnesia, relative to matched healthy comparison participants. These findings suggest, at least for close semantic links and simple language comprehension tasks, a lack of necessity for hippocampus in lexico-semantic mapping between spoken words and simple pictures.
Topics: Amnesia; Hippocampus; Humans; Language; Memory; Semantics
PubMed: 33346044
DOI: 10.1016/j.neuropsychologia.2020.107730 -
International Journal of Molecular... Aug 2023Alzheimer's disease (AD) is the most common age-related neurodegenerative disease characterized by memory loss and cognitive impairment. The causes of the disease are...
Alzheimer's disease (AD) is the most common age-related neurodegenerative disease characterized by memory loss and cognitive impairment. The causes of the disease are not well understood, as it involves a complex interaction between genetic, environmental, and epigenetic factors. SAMP8 mice have been proposed as a model for studying late-onset AD, since they show age-related learning and memory deficits as well as several features of AD pathogenesis. Epigenetic changes have been described in SAMP8 mice, although sex differences have never been evaluated. Here we used western blot and qPCR analyses to investigate whether epigenetic markers are differentially altered in the dorsal hippocampus, a region important for the regulation of learning and memory, of 9-month-old male and female SAMP8 mice. We found that H3Ac was selectively reduced in male SAMP8 mice compared to male SAMR1 control mice, but not in female mice, whereas H3K27me3 was reduced overall in SAMP8 mice. Moreover, the levels of HDAC2 and were increased, whereas the levels of HDAC4 and were reduced in SAMP8 mice compared to SAMR1. In addition, levels of HDAC1 were reduced, whereas and were selectively increased in females compared to males. Although our results are preliminary, they suggest that epigenetic mechanisms in the dorsal hippocampus are differentially regulated in male and female SAMP8 mice.
Topics: Female; Male; Animals; Mice; Neurodegenerative Diseases; Hippocampus; Alzheimer Disease; Amnesia; Epigenesis, Genetic; Memory Disorders
PubMed: 37685895
DOI: 10.3390/ijms241713084 -
The Libyan Journal of Medicine Dec 2018We evaluated the effects of intravenous dexmedetomidine during spinal anesthesia on hemodynamics, respiratory rate, oxygen saturation, sedpain, and compared them with... (Randomized Controlled Trial)
Randomized Controlled Trial
We evaluated the effects of intravenous dexmedetomidine during spinal anesthesia on hemodynamics, respiratory rate, oxygen saturation, sedpain, and compared them with those of saline infusion. Sixty American Society of Anesthesiologists physical status I and II cases were randomly divided into two groups. Patients were connected to the monitor after premedication, and spinal anesthesia was administered. Sensory and motor blockades were assessed using pinprick test and Bromage scale, respectively. Group I received dexmedetomidine infusion and Group II received saline infusion. Throughout the infusion process, hemodynamic data, respiratory rate, oxygen saturation, sedation, pain, Bromage score, amnesia, bispectral index, and side effects were recorded. Postoperative hemodynamic measurements, oxygen saturation, sedation, pain scores were obtained. Sedation and pain were evaluated using the Ramsay and visual analog scales, respectively. Analgesics were administered in cases with high scores on the visual analog scale. Postoperative analgesic consumption, side effects, treatments were recorded. No significant differences were found between the groups with respect to oxygen saturation, respiratory rate, pain, and side effects in the intraoperative period. Time to onset of sensorial block, maximum sensorial block, onset of motor block, and maximum motor block; bispectral index values; and apex heartbeat until 80 min of infusion, systolic arterial blood pressure until 90 min, and diastolic arterial blood pressure until 50 min were lower, whereas amnesia and sedation levels were higher in dexmedetomidine group. Postoperative pain and analgesic requirement were not different. Apex heartbeat at 15 min and systolic arterial blood pressure at 30 min were lower and sedation scores were higher in the dexmedetomidine infusion group. We demonstrated dexmedetomidine infusion had a hemodynamic depressant effect intraoperatively whereas it had no significant effect on peripheral oxygen saturation, respiratory rate, visual analog scale scores, and side effects. Dexmedetomidine infusion enhanced motor and sensory blockade quality and induced amnesia and sedation.
Topics: Adult; Amnesia; Anesthesia, Spinal; Arterial Pressure; Conscious Sedation; Dexmedetomidine; Heart Rate; Humans; Hypnotics and Sedatives; Infusions, Intravenous; Oxygen; Respiratory Rate; Time Factors; Urologic Surgical Procedures; Young Adult
PubMed: 29457538
DOI: 10.1080/19932820.2018.1436845 -
Annals of Clinical and Translational... Oct 2021To investigate the relationship between the topography of amyloid-β plaques, tau neurofibrillary tangles, and the overlap between the two, with cognitive dysfunction in...
OBJECTIVE
To investigate the relationship between the topography of amyloid-β plaques, tau neurofibrillary tangles, and the overlap between the two, with cognitive dysfunction in individuals without dementia.
METHODS
We evaluated 154 individuals who were assessed with amyloid-β PET with [ F]AZD4694, tau-PET with [ F]MK6240, structural MRI, and neuropsychological testing. We also evaluated an independent cohort of 240 individuals who were assessed with amyloid-β PET with [ F]Florbetapir, tau-PET with [ F]Flortaucipir, structural MRI, and neuropsychological testing. Using the VoxelStats toolbox, we conducted voxel-wise linear regressions between amyloid-PET, tau-PET, and their interaction with cognitive function, correcting for age, sex, and years of education.
RESULTS
In both cohorts, we observed that tau-PET standardized uptake value ratio in medial temporal lobes was associated with clinical dementia rating Sum of Boxes (CDR-SoB) scores independently of local amyloid-PET uptake (FWE corrected at p < 0.001). We also observed in both cohorts that in regions of the neocortex, associations between neocortical tau-PET and clinical function were dependent on local amyloid-PET (FWE corrected at p < 0.001).
INTERPRETATION
In medial temporal brain regions, characterized by the accumulation of tau pathology in the absence of amyloid-β, tau had direct associations with cognitive dysfunction. In brain regions characterized by the accumulation of both amyloid-β and tau pathologies such as the posterior cingulate and medial frontal cortices, tau's relationship with cognitive dysfunction was dependent on local amyloid-β concentrations. Our results provide evidence that amyloid-β in Alzheimer's disease influences cognition by potentiating the deleterious effects of tau pathology.
Topics: Aged; Aged, 80 and over; Amnesia; Amyloid beta-Peptides; Cognitive Dysfunction; Cohort Studies; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neocortex; Positron-Emission Tomography; tau Proteins
PubMed: 34617688
DOI: 10.1002/acn3.51457 -
BMC Complementary Medicine and Therapies Jul 2023Amnesic mild cognitive impairment (aMCI) is the main subtype of mild cognitive impairment (MCI) and has the highest risk of conversion to Alzheimer's disease (AD) among...
BACKGROUND
Amnesic mild cognitive impairment (aMCI) is the main subtype of mild cognitive impairment (MCI) and has the highest risk of conversion to Alzheimer's disease (AD) among all MCI subtypes. Episodic memory impairment is the early cognitive impairment of aMCI, which has become an important target for AD prevention. Previous clinical evidence has shown that acupuncture can improve the cognitive ability of MCI patients. This experiment aimed to observe the efficacy and neural mechanism of TiaoshenYizhi acupuncture on the episodic memory of patients with aMCI.
METHODS
In this multicenter, parallel-group, double-blind, randomized controlled trial, 360 aMCI participants will be recruited from six subcenters and randomly assigned to the acupuncture group, sham acupuncture group, and control group. The acupuncture group will receive TiaoshenYizhi (TSYZ) acupuncture, the sham acupuncture group will use streitberger sham acupuncture, and the control group will only receive free health education. Participants in the two acupuncture groups will receive real acupuncture treatment or placebo acupuncture three times per week, 24 sessions over 8 consecutive weeks. The primary outcome will be global cognitive ability. Secondary outcomes will be a specific cognitive domain, including episodic memory and execution ability, electroencephalogram, and functional magnetic resonance imaging data. Outcomes will be measured at baseline and the fourth and eighth weeks after randomization. Repeated measurement analysis of variance and a mixed linear model will be used to observe the intervention effect.
DISCUSSION
The protocol will give a detailed procedure to the multicenter clinical trial to further evaluate the efficacy and neural mechanism of TiaoshenYizhi acupuncture on episodic memory in patients with aMCI. From this research, we expect to provide clinical evidence for early aMCI management.
TRIAL REGISTRATION
http://www.chictr.org.cn/edit.aspx?pid=142612&htm=4 , identifier: ChiCTR2100054009.
Topics: Humans; Memory, Episodic; Cognitive Dysfunction; Cognition; Acupuncture Therapy; Amnesia; Alzheimer Disease; Randomized Controlled Trials as Topic; Multicenter Studies as Topic
PubMed: 37507779
DOI: 10.1186/s12906-023-04059-9 -
The Primary Care Companion For CNS... Apr 2021
Topics: Amnesia; Amnesia, Transient Global; Humans
PubMed: 34000128
DOI: 10.4088/PCC.20l02631 -
Nature Communications Aug 2020Post-traumatic stress disorder (PTSD) is characterized by emotional hypermnesia on which preclinical studies focus so far. While this hypermnesia relates to salient...
Post-traumatic stress disorder (PTSD) is characterized by emotional hypermnesia on which preclinical studies focus so far. While this hypermnesia relates to salient traumatic cues, partial amnesia for the traumatic context can also be observed. Here, we show in mice that contextual amnesia is causally involved in PTSD-like memory formation, and that treating the amnesia by re-exposure to all trauma-related cues cures PTSD-like hypermnesia. These findings open a therapeutic perspective based on trauma contextualization and the underlying hippocampal mechanisms.
Topics: Amnesia; Animals; Avoidance Learning; Conditioning, Psychological; Cues; Emotions; Hippocampus; Humans; Male; Memory; Mice, Inbred C57BL; Stress Disorders, Post-Traumatic
PubMed: 32839437
DOI: 10.1038/s41467-020-18002-w -
Current Biology : CB Jul 2018Hippocampus-dependent, event-related memories formed in early infancy in human and non-human animals are rapidly forgotten. Recently we found that high levels of...
Hippocampus-dependent, event-related memories formed in early infancy in human and non-human animals are rapidly forgotten. Recently we found that high levels of hippocampal neurogenesis contribute to accelerated rates of forgetting during infancy. Here, we ask whether these memories formed in infancy are permanently erased (i.e., storage failure) or become progressively inaccessible with time (i.e., retrieval failure). To do this, we developed an optogenetic strategy that allowed us to permanently express channelrhodopsin-2 (ChR2) in neuronal ensembles that were activated during contextual fear encoding in infant mice. We then asked whether reactivation of ChR2-tagged ensembles in the dentate gyrus was sufficient for memory recovery in adulthood. We found that optogenetic stimulation of tagged dentate gyrus neurons recovered "lost" infant memories up to 3 months following training and that memory recovery was associated with broader reactivation of tagged hippocampal and cortical neuronal ensembles.
Topics: Age Factors; Amnesia; Animals; Channelrhodopsins; Dentate Gyrus; Fear; Female; Male; Memory; Mice; Optogenetics
PubMed: 29983316
DOI: 10.1016/j.cub.2018.05.059