(remote memory) articles in PubMed
- Spatial memory formation differentially affects c-Fos expression in retrosplenial areas during place avoidance training in rats. [Journal Article]
- Acta Neurobiol Exp (Wars) 2016; 76(3):244-265AN
- The retrosplenial cortex is involved in spatial memory function, but the contribution of its individual areas is not well known. To elucidate the involvement of retrosplenial cortical areas 29c and 3...
The retrosplenial cortex is involved in spatial memory function, but the contribution of its individual areas is not well known. To elucidate the involvement of retrosplenial cortical areas 29c and 30 in spatial memory, we analyzed the expression of c-Fos in these areas in the experimental group of rats that were trained in a spatial place avoidance task, i.e. to avoid shocks presented in an unmarked sector of a stable arena under light conditions. Control rats were trained in the same context as the experimental rats either without (Control-noUS) or with shocks (Control-US) that were delivered in a random, noncontingent manner for three days. On the first day of place avoidance learning, the experimental group exhibited c-Fos induction in area 29c, similar to both control groups. In area 30, similarly high levels of c-Fos expression were observed in the experimental and Control-US groups. On the third day of training, when the experimental group efficiently avoided c-Fos expression in areas 29c and 30 was lower compared with the first day of training. In area 29c c-Fos level was also lower in the experimental than in comparison to the Control-US group. In area 30, c-Fos expression in the experimental group was lower than in both control groups. In conclusion, areas 29c and 30 appear to be activated during spatial memory acquisition on the first day of training, whereas area 30 seems suppressed during long-term memory functioning on the third day of training when rats effectively avoid.
- Effects of repetitive transcranial magnetic stimulation on non-veridical decision making. [Journal Article]
- Acta Neurobiol Exp (Wars) 2016; 76(3):182-191AN
- We test the emerging hypothesis that prefrontal cortical mechanisms involved in non-veridical decision making do not overlap with those of veridical decision making. Healthy female subjects performed...
We test the emerging hypothesis that prefrontal cortical mechanisms involved in non-veridical decision making do not overlap with those of veridical decision making. Healthy female subjects performed an experimental task assessing free choice, agent-centered decision making (The Cognitive Bias Task) and a veridical control task related to visuospatial working memory (the Moving Spot Task). Transcranial magnetic stimulation (TMS) was applied to the left and right dorsolateral prefrontal cortex (DLPFC) using 1 Hz and 10 Hz (intermittent) rTMS and sham protocols. Both 1 Hz and 10 Hz stimulation of the DLPFC triggered a shift towards a more context-independent, internal representations driven non-veridical selection bias. A significantly reduced preference for choosing objects based on similarity was detected, following both 1 Hz and 10 Hz treatment of the right as well as 1 Hz rTMS of the left DLPFC. 1 Hz rTMS treatment of the right DLPFC also triggered a significant improvement in visuospatial working memory performance on the veridical task. The effects induced by prefrontal TMS mimicked those of posterior lesions, suggesting that prefrontal stimulation influenced neuronal activity in remote cortical regions interconnected with the stimulation site via longitudinal fasciculi.
- The Role of Long-Term Memory in a Test of Visual Working Memory: Proactive Facilitation but No Proactive Interference. [Journal Article]
- J Exp Psychol Learn Mem Cogn 2016 Sep 29JE
- We report 4 experiments examining whether associations in visual working memory are subject to proactive interference from long-term memory (LTM). Following a long-term learning phase in which partic...
We report 4 experiments examining whether associations in visual working memory are subject to proactive interference from long-term memory (LTM). Following a long-term learning phase in which participants learned the colors of 120 unique objects, a working memory (WM) test was administered in which participants recalled the precise colors of 3 concrete objects in an array. Each array in the WM test consisted of 1 old (previously learned) object with a new color (old-mismatch), 1 old object with its old color (old-match), and 1 new object. Experiments 1 to 3 showed that WM performance was better in the old-match condition than in the new condition, reflecting a beneficial contribution from LTM. In the old-mismatch condition, participants sometimes reported colors associated with the relevant shape in LTM, but the probability of successful recall was equivalent to that in the new condition. Thus, information from LTM only intruded in the absence of reportable information in WM. Experiment 4 tested for, and failed to find, proactive interference from the preceding trial in the WM test: Performance in the old-mismatch condition, presenting an object from the preceding trial with a new color, was equal to performance with new objects. Experiment 5 showed that long-term memory for object-color associations is subject to proactive interference. We conclude that the exchange of information between LTM and WM appears to be controlled by a gating mechanism that protects the contents of WM from proactive interference but admits LTM information when it is useful. (PsycINFO Database Record
- Tc-99m-ECD SPECT as the measure for therapeutic response in patients with cobalamin deficiency: Two case reports. [Journal Article]
- Medicine (Baltimore) 2016; 95(39):e4851M
- CONCLUSIONS: Given that the ACC integrates the limbic system and frontosubcortical circuits and the PFC governs executive function, the extent and severity of hypofrontality may be responsible for the worse prognosis. Our Tc-99m-ECD SPECT observations revealed that the negative impact on cerebral metabolic tone is relevant to the severity of Cbl deficiency, and the functional integrity of the ACC and PFC is highly associated with the preservation of global cognitive function in our cases with Cbl deficiency.
- Toward an Integration of Deep Learning and Neuroscience. [Journal Article]
- Front Comput Neurosci 2016; 10:94FC
- Neuroscience has focused on the detailed implementation of computation, studying neural codes, dynamics and circuits. In machine learning, however, artificial neural networks tend to eschew precisely...
Neuroscience has focused on the detailed implementation of computation, studying neural codes, dynamics and circuits. In machine learning, however, artificial neural networks tend to eschew precisely designed codes, dynamics or circuits in favor of brute force optimization of a cost function, often using simple and relatively uniform initial architectures. Two recent developments have emerged within machine learning that create an opportunity to connect these seemingly divergent perspectives. First, structured architectures are used, including dedicated systems for attention, recursion and various forms of short- and long-term memory storage. Second, cost functions and training procedures have become more complex and are varied across layers and over time. Here we think about the brain in terms of these ideas. We hypothesize that (1) the brain optimizes cost functions, (2) the cost functions are diverse and differ across brain locations and over development, and (3) optimization operates within a pre-structured architecture matched to the computational problems posed by behavior. In support of these hypotheses, we argue that a range of implementations of credit assignment through multiple layers of neurons are compatible with our current knowledge of neural circuitry, and that the brain's specialized systems can be interpreted as enabling efficient optimization for specific problem classes. Such a heterogeneously optimized system, enabled by a series of interacting cost functions, serves to make learning data-efficient and precisely targeted to the needs of the organism. We suggest directions by which neuroscience could seek to refine and test these hypotheses.
- Rho GTPase complementation underlies BDNF-dependent homo- and heterosynaptic plasticity. [Journal Article]
- Nature 2016 Sep 28Nat
- The Rho GTPase proteins Rac1, RhoA and Cdc42 have a central role in regulating the actin cytoskeleton in dendritic spines, thereby exerting control over the structural and functional plasticity of sp...
The Rho GTPase proteins Rac1, RhoA and Cdc42 have a central role in regulating the actin cytoskeleton in dendritic spines, thereby exerting control over the structural and functional plasticity of spines and, ultimately, learning and memory. Although previous work has shown that precise spatiotemporal coordination of these GTPases is crucial for some forms of cell morphogenesis, the nature of such coordination during structural spine plasticity is unclear. Here we describe a three-molecule model of structural long-term potentiation (sLTP) of murine dendritic spines, implicating the localized, coincident activation of Rac1, RhoA and Cdc42 as a causal signal of sLTP. This model posits that complete tripartite signal overlap in spines confers sLTP, but that partial overlap primes spines for structural plasticity. By monitoring the spatiotemporal activation patterns of these GTPases during sLTP, we find that such spatiotemporal signal complementation simultaneously explains three integral features of plasticity: the facilitation of plasticity by brain-derived neurotrophic factor (BDNF), the postsynaptic source of which activates Cdc42 and Rac1, but not RhoA; heterosynaptic facilitation of sLTP, which is conveyed by diffusive Rac1 and RhoA activity; and input specificity, which is afforded by spine-restricted Cdc42 activity. Thus, we present a form of biochemical computation in dendrites involving the controlled complementation of three molecules that simultaneously ensures signal specificity and primes the system for plasticity.
- The Limited Capacity of Sleep-Dependent Memory Consolidation. [Journal Article]
- Front Psychol 2016; 7:1368FP
- Sleep supports memory consolidation. However, the conceptually important influence of the amount of items encoded in a memory test on this effect has not been investigated. In two experiments, partic...
Sleep supports memory consolidation. However, the conceptually important influence of the amount of items encoded in a memory test on this effect has not been investigated. In two experiments, participants (n = 101) learned lists of word-pairs varying in length (40, 160, 320 word-pairs) in the evening before a night of sleep (sleep group) or of sleep deprivation (wake group). After 36 h (including a night allowing recovery sleep) retrieval was tested. Compared with wakefulness, post-learning sleep enhanced retention for the 160 word-pair condition (p < 0.01), importantly, this effect completely vanished for the 320 word-pair condition. This result indicates a limited capacity for sleep-dependent memory consolidation, which is consistent with an active system consolidation view on sleep's role for memory, if it is complemented by processes of active forgetting and/or gist abstraction. Whereas the absolute benefit from sleep should have increased with increasing amounts of successfully encoded items, if sleep only passively protected memory from interference. Moreover, the finding that retention performance was significantly diminished for the 320 word-pair condition compared to the 160 word-pair condition in the sleep group, makes it tempting to speculate that with increasing loads of information encoded during wakefulness, sleep might favor processes of forgetting over consolidation.
- Your perspective and my benefit: multiple lesion models of self-other integration strategies during social bargaining. [Journal Article]
- Brain 2016 Sep 27B
- Recursive social decision-making requires the use of flexible, context-sensitive long-term strategies for negotiation. To succeed in social bargaining, participants' own perspectives must be dynamica...
Recursive social decision-making requires the use of flexible, context-sensitive long-term strategies for negotiation. To succeed in social bargaining, participants' own perspectives must be dynamically integrated with those of interactors to maximize self-benefits and adapt to the other's preferences, respectively. This is a prerequisite to develop a successful long-term self-other integration strategy. While such form of strategic interaction is critical to social decision-making, little is known about its neurocognitive correlates. To bridge this gap, we analysed social bargaining behaviour in relation to its structural neural correlates, ongoing brain dynamics (oscillations and related source space), and functional connectivity signatures in healthy subjects and patients offering contrastive lesion models of neurodegeneration and focal stroke: behavioural variant frontotemporal dementia, Alzheimer's disease, and frontal lesions. All groups showed preserved basic bargaining indexes. However, impaired self-other integration strategy was found in patients with behavioural variant frontotemporal dementia and frontal lesions, suggesting that social bargaining critically depends on the integrity of prefrontal regions. Also, associations between behavioural performance and data from voxel-based morphometry and voxel-based lesion-symptom mapping revealed a critical role of prefrontal regions in value integration and strategic decisions for self-other integration strategy. Furthermore, as shown by measures of brain dynamics and related sources during the task, the self-other integration strategy was predicted by brain anticipatory activity (alpha/beta oscillations with sources in frontotemporal regions) associated with expectations about others' decisions. This pattern was reduced in all clinical groups, with greater impairments in behavioural variant frontotemporal dementia and frontal lesions than Alzheimer's disease. Finally, connectivity analysis from functional magnetic resonance imaging evidenced a fronto-temporo-parietal network involved in successful self-other integration strategy, with selective compromise of long-distance connections in frontal disorders. In sum, this work provides unprecedented evidence of convergent behavioural and neurocognitive signatures of strategic social bargaining in different lesion models. Our findings offer new insights into the critical roles of prefrontal hubs and associated temporo-parietal networks for strategic social negotiation.
- Neurobehavioral effects of vigabatrin and its ability to induce DNA damage in brain cells after acute treatment in rats. [Journal Article]
- Psychopharmacology (Berl) 2016 Sep 27P
- CONCLUSIONS: VGB did not affect STM and LTM, but the drug impaired the exploration and locomotion likely associated with its sedative effect. In addition, no DNA damage in cortex and hippocampus was detected after behavioral testing, when brain GABA levels are already increased.
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- Depletion of primary cilia from mature dentate granule cells impairs hippocampus-dependent contextual memory. [Journal Article]
- Sci Rep 2016; 6:34370SR
- The primary cilium, a sensory organelle, regulates cell proliferation and neuronal development of dentate granule cells in the hippocampus. However, its role in the function of mature dentate granule...
The primary cilium, a sensory organelle, regulates cell proliferation and neuronal development of dentate granule cells in the hippocampus. However, its role in the function of mature dentate granule cells remains unknown. Here we specifically depleted and disrupted ciliary proteins IFT20 and Kif3A (respectively) in mature dentate granule cells and investigated hippocampus-dependent contextual memory and long-term plasticity at mossy fiber synapses. We found that depletion of IFT20 in these cells significantly impaired context-dependent fear-related memory. Furthermore, we tested synaptic plasticity of mossy fiber synapses in area CA3 and found increased long-term potentiation upon depletion of IFT20 or disruption of Kif3A. Our findings suggest a role of primary cilia in the memory function of mature dentate granule cells, which may result from abnormal mossy fiber synaptic plasticity. A direct link between the primary cilia of mature dentate granule cells and behavior will require further investigation using independent approaches to manipulate primary cilia.