Extinction, renewal, and spontaneous recovery of a spatial preference in the water maze.

Four experiments with C57BL/6 mice investigated extinction of a spatial preference in the Morris water maze. In Experiment 1, a spatial preference was extinguished by exposing mice to the water maze in the absence of a platform but in the presence of the distal spatial cues. In Experiment 2, extinction occurred when the platform was removed from the pool, when it was presented in random locations, or when it was presented consistently in the opposite location. Contextual renewal (Experiment 3) and spontaneous recovery (Experiment 4) of spatial preferences argue against an interpretation of extinction in terms of unlearning and instead suggest that extinction in the water maze, like extinction in Pavlovian conditioning, suppresses the original association. Implications of these findings for theories of spatial learning and hippocampal function are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of the adaptive specialization hypothesis: Population differences in caching, memory, and the hippocampus in black-capped chickadees (Poecile atricapilla).

To test the hypothesis that accurate cache recovery is more critical for birds that live in harsh conditions where the food supply is limited and unpredictable, the authors compared food caching, memory, and the hippocampus of black-capped chickadees (Poecile atricapilla) from Alaska and Colorado. Under identical laboratory conditions, Alaska chickadees (a) cached significantly more food; (b) were more efficient at cache recovery; (c) performed more accurately on one-trial associative learning tasks in which birds had to rely on spatial memory, but did not differ when tested on a nonspatial version of this task; and (d) had significantly larger hippocampal volumes containing more neurons compared with Colorado chickadees. The results support the hypothesis that these population differences may reflect adaptations to a harsh environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spiking Phineas Gage: A Neurocomputational Theory of Cognitive-Affective Integration in Decision Making.

The authors present a neurological theory of how cognitive information and emotional information are integrated in the nucleus accumbens during effective decision making. They describe how the nucleus accumbens acts as a gateway to integrate cognitive information from the ventromedial prefrontal cortex and the hippocampus with emotional information from the amygdala. The authors have modeled this integration by a network of spiking artificial neurons organized into separate areas and used this computational model to simulate 2 kinds of cognitive-affective integration. The model simulates successful performance by people with normal cognitive-affective integration. The model also simulates the historical case of Phineas Gage as well as subsequent patients whose ability to make decisions became impeded by damage to the ventromedial prefrontal cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory Reconsolidation Hypothesis Revived but Restrained: Theoretical Comment on Biedenkapp and Rudy (2004).

J. C. Biedenkapp and J. W. Rudy (2004; see record 2004-19432-009) reported that the protein synthesis inhibitor anisomycin administered into the hippocampus after context preexposure or contextual fear conditioning impaired subsequent retention performance. In contrast, anisomycin administered after context memory retrieval did not impair subsequent contextual fear conditioning. Their findings challenge the hypothesis that memory retrieval induces memory reconsolidation and suggest that the hypothesis needs to be constrained to account for negative findings. However, their evidence does not suggest compelling clues to how the hypothesis might be constrained to accommodate the findings. Thus, it is not yet clear whether their findings can be explained by a revised reconsolidation hypothesis, or whether some other hypothesis is required to account for postretrieval memory impairment, when it is observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impaired place learning and unimpaired cue learning in hippocampal-lesioned pigeons.

Hippocampal processing is often crucial for normal spatial learning and memory in both birds and mammals, suggesting a general similarity in avian and mammalian hippocampal function. However, few studies using birds have examined the effect of hippocampal lesions on spatial tasks analogous to those typically used with mammals. Therefore, we examined how hippocampal lesions would affect the performance of pigeons in a dry version of the water maze. Experiment 1 showed that hippocampal-lesioned birds were impaired in acquiring the location of hidden food in the maze. Experiment 2 showed that hippocampal-lesioned birds were not impaired when a single cue indicated the location of hidden food. These results support the notion that avian and mammalian hippocampal functions are quite similar, in terms of the tasks for which their processing is crucial and the tasks for which it is not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The complex-shaped ‘perforated’ synapse,a problem in quantitative stereology of the brain

Failure to appreciate the consequences for stereological work of the simultaneous presence of complex-shaped perforated and disc-like non-perforated synapses in brain tissue results in underestimation of synaptic profile length and overestimation of synaptic density when measured in randomly selected ultrathin E-PTA slices. This problem can be solved by using serial slices and a calculation method which makes no assumptions about synaptic size and shape. A three-dimensional reconstruction is unnecessary.     

Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury.

[Correction Notice: An erratum for this article was reported in Vol 22(6) of Neuropsychology (see record 2008-15268-012). Author Ramona O. Hopkins's name was misspelled as Romona O. Hopkins.] Human anterograde amnesia can result from a variety of etiologies, including hypoxic brain injury and anterior communicating artery (ACoA) aneurysm rupture. Although each etiology can cause a similarly severe disruption in declarative memory for verbal and visual material, there may be differences in incrementally acquired, feedback-based learning, as well as generalization. Here, 6 individuals who survived hypoxic brain injury, 7 individuals who survived ACoA aneurysm rupture, and 13 matched controls were tested on 2 tasks that included a feedback-based learning phase followed by a transfer phase in which familiar information is presented in new ways. In both tasks, the ACoA group was slow on initial learning, but those patients who completed the learning phase went on to transfer as well as controls. In the hypoxic group, 1 patient failed to complete either task; the remaining hypoxic group did not differ from controls during learning of either task, but was impaired on transfer. These results highlight a difference in feedback-based learning in 2 amnesic etiologies, despite similar levels of declarative memory impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury": Correction.

Reports an error in "Learning and generalization deficits in patients with memory impairments due to anterior communicating artery aneurysm rupture or hypoxic brain injury" by Catherine E. Myers, Ramona O. Hopkins, John DeLuca, Nancy B. Moore, Leo J. Wolansky, Jennifer M. Sumner and Mark A. Gluck (Neuropsychology, 2008[Sep], Vol 22[5], 681-686). Author Ramona O. Hopkins's name was misspelled as Romona O. Hopkins. (The following abstract of the original article appeared in record 2008-11707-013.) Human anterograde amnesia can result from a variety of etiologies, including hypoxic brain injury and anterior communicating artery (ACoA) aneurysm rupture. Although each etiology can cause a similarly severe disruption in declarative memory for verbal and visual material, there may be differences in incrementally acquired, feedback-based learning, as well as generalization. Here, 6 individuals who survived hypoxic brain injury, 7 individuals who survived ACoA aneurysm rupture, and 13 matched controls were tested on 2 tasks that included a feedback-based learning phase followed by a transfer phase in which familiar information is presented in new ways. In both tasks, the ACoA group was slow on initial learning, but those patients who completed the learning phase went on to transfer as well as controls. In the hypoxic group, 1 patient failed to complete either task; the remaining hypoxic group did not differ from controls during learning of either task, but was impaired on transfer. These results highlight a difference in feedback-based learning in 2 amnesic etiologies, despite similar levels of declarative memory impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RGS14 Regulation of Post-Synaptic Signaling and Spine Plasticity in Brain

The regulator of G-protein signaling 14 (RGS14) is a multifunctional signaling protein that regulates post synaptic plasticity in neurons. RGS14 is expressed in the brain regions essential for learning, memory, emotion, and stimulus-induced behaviors, including the basal ganglia, limbic system, and cortex. Behaviorally, RGS14 regulates spatial and object memory, female-specific responses to cued fear conditioning, and environmental- and psychostimulant-induced locomotion. At the cellular level, RGS14 acts as a scaffolding protein that integrates G protein, Ras/ERK, and calcium/calmodulin signaling pathways essential for spine plasticity and cell signaling, allowing RGS14 to naturally suppress long-term potentiation (LTP) and structural plasticity in hippocampal area CA2 pyramidal cells. Recent proteomics findings indicate that RGS14 also engages the actomyosin system in the brain, perhaps to impact spine morphogenesis. Of note, RGS14 is also a nucleocytoplasmic shuttling protein, where its role in the nucleus remains uncertain. Balanced nuclear import/export and dendritic spine localization are likely essential for RGS14 neuronal functions as a regulator of synaptic plasticity. Supporting this idea, human genetic variants disrupting RGS14 localization also disrupt RGS14’s effects on plasticity. This review will focus on the known and unexplored roles of RGS14 in cell signaling, physiology, disease and behavior.     

矿物药青礞石对PTZ点燃癫痫大鼠脑组织中氨基酸神经递质含量的影响

建立了超高效液相色谱-三重四极杆-线性离子阱质谱（Qtrap-UPLC-MS/MS）法同时测定大鼠脑组织中4种氨基酸类神经递质,研究了矿物药青礞石原药材粉末、水煎液、药渣对戊四氮（Pentylenetetrazol,PTZ）点燃癫痫模型大鼠脑组织中氨基酸类神经递质含量的影响。在ESI⁺电离模式下,采用多反应监测扫描方式测定脑组织（皮层,海马）中谷氨酸（Glu）、甘氨酸（Gly）、天冬氨酸（Asp）及γ-氨基丁酸（GABA）的含量。结果表明：4种氨基酸的线性关系良好,精密度、准确度均符合生物样品的分析要求。大鼠给予青礞石不同样品后,脑组织皮层和海马中兴奋性神经递质Glu、Asp水平显著降低。与模型组相比,皮层中Gly占氨基酸总含量的百分比均增加,Asp/Gly值、Glu/Gly值均降低;海马中,各组Glu、Asp、Gly、GABA的浓度均降低。这说明,矿物药青礞石能有效降低PTZ点燃大鼠脑内兴奋性氨基酸递质含量,调节皮层和海马区Gly含量。