The Role of CA1 in the Acquisition of an Object-Trace-Odor Paired Associate Task.

This experiment was designed to determine whether adding a temporal component to an object-odor association task would recruit the hippocampus. The rats were given CA1, CA3, or control lesions prior to learning the object-trace-odor task. Rats were presented with an object for 10 s, after which the object was removed, followed by a 10-s trace period, followed by the presentation of an odor 50 cm away. If the odor and the object were paired, rats were to dig in the odor cup for a reward. If unpaired, rats were to refrain from digging. Rats that had CA1 lesions were unable to make the association, whereas rats that had CA3 lesions performed as well as controls. These results support the idea that the hippocampus is involved in forming arbitrary associations that do not necessarily involve space as long as they involve a temporal component. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lesions of the Dorsal Hippocampus Block Trace Fear Conditioned Potentiation of Startle.

Several studies show that the hippocampus is critical for the memories mediating trace and contextual fear conditioning. This study investigates whether N-methyl-D-aspartate-induced lesions of the dorsal hippocampus made prior to training affect context fear conditioning and trace fear conditioning measured with the fear-potentiated startle. Pretraining excitotoxic lesions of the dorsal hippocampus blocked acquisition of trace fear conditioning to a tone stimulus but did not affect context fear conditioning. These data indicate that without a dorsal hippocampus rats are unable to acquire trace conditioning but can acquire contextual fear when fear is measured by potentiation of the startle response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective dysgranular retrosplenial cortex lesions in rats disrupt allocentric performance of the radial-arm maze task.

The present study provides the 1st report on the effects of selective lesions of the dysgranular portion of the retrosplenial cortex in rats. Excitotoxic lesions of the dysgranular area were sufficient to impair behavior in the radial-arm maze by biasing the strategy used to solve the task. In particular, rats with dysgranular retrosplenial lesions were less reliant on distal visual cues to control performance of a working memory task in the radial-arm maze. Instead, they were more reliant on using a motor turning strategy to solve the task. This change in strategy is consistent with anatomical data showing that the dysgranular region is the primary recipient of visual inputs to the rat retrosplenial cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional Significance of Selective Expression of ERα and ERβ in Mammary Gland Organ Culture

Thoracic pair of mammary glands from steroid hormone-pretreated mice respond to hormones structurally and functionally in organ culture. A short exposure of glands for 24 h to 7,12 Dimethylbenz(a)anthracene (DMBA) during a 24-day culture period induced alveolar or ductal lesions. Methods: To differentiate the functional significance of ERα and ERβ, we employed estrogen receptor (ER) knockout mice. We compared the effects of DMBA on the development of preneoplastic lesions in the glands in the absence of ERα (αERKO) and ERβ (βERKO) using an MMOC protocol. Glands were also subjected to microarray analyses. We showed that estradiol can be replaced by EGF for pretreatment of mice. The carcinogen-induced lesions developed under both steroids and EGF pretreatment protocols. The glands from αERKO did not develop any lesions, whereas in βERKO mice in which ERα is intact, mammary alveolar lesions developed. Comparison of microarrays of control, αERKO and βERKO mice showed that ERα was largely responsible for proliferation and the MAP kinase pathways, whereas ERβ regulated steroid metabolism-related genes. The results indicate that ERα is essential for the development of precancerous lesions. Both subtypes, ERα and Erβ, differentially regulated gene expression in mammary glands in organ cultures.     

小米谷糠多肽对肝损伤及癌前病变的抑制作用

目的：观察小米谷糠多肽的抗肿瘤和抑制化学性肝损伤作用。方法：分别用菠萝蛋白酶、木瓜蛋白酶、537酸性蛋白酶水解小米谷糠,得到3 种多肽;先用噻唑蓝法检测3 种谷糠多肽的体外抗肿瘤作用,然后用抗肿瘤效果最好的多肽喂食经氨基比林-NaNO2诱导的肝损伤小鼠,并作肝组织学观察。结果：当菠萝蛋白酶水解的谷糠多肽质量浓度为50 mg/mL时,S180和H22肿瘤细胞的抑制率可达到56.28%和53.73%,该多肽在10 g/（kg·d）剂量可显著降低小鼠肝脏丙二醛含量和血清谷草转氨酶、谷丙转氨酶活性（P＜0.01）,并提高肝脏谷胱甘肽过氧化物酶活性（P＜0.01）。组织切片显示,模型组小鼠肝细胞损伤严重,谷糠多肽高剂量组动物的肝细胞形态基本正常。结论：菠萝蛋白酶水解的谷糠多肽具有抑制肝损伤及癌前期病变的作用。     

Gastroprotective effect of selenium on ethanol-induced gastric damage in rats

In the present study, we examined the gastroprotective effect of selenium against ethanol-induced gastric mucosal lesions in rats. The gastric mucosal lesions were produced by oral administration with various concentrations of ethanol for three days, and 80% ethanol treatment was determined to be the optimal condition for induction of gastric damage. To identify the protective effect of selenium on ethanol-induced gastric damage, various doses of selenium were given as pretreatment for three days, and then gastric damage was induced by 80% ethanol treatment. Selenium showed a protective effect against ethanol-induced gastric mucosal lesions in a dose dependent manner. Specifically, 100 μg/kg selenium showed the highest level of gastroprotection. In addition, selenium markedly attenuated ethanol-induced lipid peroxidation in gastric mucosa and increased activities of radical scavenging enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase in a dose-dependent manner. Histological data showed that 100 μg/kg selenium distinctly reduced the depth and severity of the ethanol induced gastric lesion. These results clearly demonstrate that selenium inhibits the formation of ethanol-induced gastric mucosal lesions through prevention of lipid peroxidation and activation of enzymatic radical scavenging.     

White matter lesions account for all age-related declines in speed but not in intelligence.

MRI scans measured white matter lesion prevalence (WMLP) in 65 people ages 65-84 years who also took 17 cognitive tests: 3 tests of general fluid intelligence, 3 of vocabulary, 2 of episodic and 3 of working memory, 2 of processing speed, and 4 of frontal and executive function. Entry of age with WMLP into regression equations as predictors of test scores showed that inferences about the functional relationships between markers of brain aging and cognitive impairments are seriously misleading if they are based on simple correlations alone. A new finding that WMLP accounts for all of the age-related variance between individuals in tests of speed and executive ability but for none of the age-related variance in intelligence revises current hypotheses that gross brain changes affect general fluid intelligence and other mental abilities solely through their effects on information-processing speed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neonatal amygdala lesions: Co-occuring impact on social/fear-related behavior and cocaine sensitization in adult rats.

Neurodevelopmental abnormalities of temporal-limbic structures may underlie both adult psychiatric syndromes and increased addiction vulnerability, leading to high frequencies of "dual diagnosis" disorders. Although the amygdala is implicated in various mental disorders and drug addiction, no studies have explored the impact of early developmental damage to the amygdala on phenotypes relating to mental illness and addictions as co-occurring processes. We tested rats with neonatal amygdala lesions (NAML) vs. SHAM-operated controls in a battery of tests-novel field activity, elevated plus maze (EPM), and social interaction (SI) at baseline and after odor and restraint stress-followed by measures of cocaine sensitization (15 mg/kg vs. saline × 5 days + challenge session 2 weeks later) and remeasurement of SI. NAMLs showed increased novelty-related locomotion, less fear responding in the EPM, and resistance to predator-odor--but not to restraint-induced suppression of SI. NAMLs also had elevated cocaine sensitization profiles, and cocaine history differentially affected subsequent SI in NAMLs compared with SHAMs. NAMLs may provide models for understanding a shared neurobiological basis for and complex interactions among psychiatric symptoms, drug exposure history, and addiction vulnerability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Text comprehension after brain injury: Left prefrontal lesions affect inference processes.

Comprehending language in context requires inferencing, particularly for the establishment of local coherence. In the neurolinguistic literature, an inference deficit after right hemisphere brain damage has been postulated, but clinical observation and imaging data suggest that left-frontal lesions might also result in inference deficits. In the present experiment, 25 nonaphasic patients performed a coherence judgment task requiring them to indicate a pragmatic connection between 2 successively presented sentences. Patients with left-temporal or right-frontal lesions performed the task well. In contrast, patients with left- and bifrontal lesions exhibited the most severe deficit. Both error rates and response times were elevated for coherent trials as compared with incoherent trials. These results confirm that the left-frontal lobe contributes to inference processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disconnection of the amygdala central nucleus and the substantia innominata/nucleus basalis magnocellularis disrupts performance in a sustained attention task.

The basal forebrain cholinergic system is broadly implicated in the regulation of attention. Disruptions in the function of this system produce impairments in many attentional functions, including the performance of well-learned responses under increased attentional load and the surprise-induced enhancement of learning rate. Similarly, lesions of the amygdala central nucleus (CeA) have been found to impair attentional function in some circumstances. In the present article, the effects of lesions that disconnected CeA from the cholinergic substantia innominata/nucleus basalis magnocellularis (SI/nBM) on performance are examined in a modified 5-choice serial reaction time (5CSRT) task, thought to assess selective or sustained attention. The lesions impaired performance under conditions of increased attentional load, suggesting that a circuit that includes CeA and SI/nBM regulates these aspects of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)