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Objective: To study the effects of regional cerebral blood flow (rCBF) perfusion on learning and memory function in special brain areas and its molecular mechanism in rat. Methods: Sixty-four adult male healthy Sprague-Dawley (SD) rats were randomly divided into two groups: A false operation group and an operation group. The false operation group was randomly divided into four subgroups (A0, B0, C0, and D0) and the operation group was randomly divided into four subgroups (A, B, C, and D), with eight rats in each subgroup. The operation group underwent bilateral common carotid artery permanent ligation, while the other group only underwent a skin incision without the bilateral common carotid artery permanent ligation. Learning memory function of rats in each subgroup was measured using a Y-maze at 4 h, 8 h, 24 h, and 3 days after surgery. The rCBF in the right frontal lobe and hippocampus was detected using the Periflux PF model laser Doppler flowmetry and c-fos, c-jun, Bcl-2, and Bax protein expression in the right frontal lobe and hippocampus was measured using immunohistochemistry. Results: The rCBF in the right frontal lobule division and right hippocampus division was significantly lower in the operation group than in the false operation group (P < 0.05). The error number (EN), time to reach the target, and total reaction time (TRT) for the learning index using the Y-type labyrinth test in the operation group were significantly higher than that in the false operation group (P < 0.05); however, the active avoid rate in the operation group was significantly lower than that of the false operation group. Expression of c-fos and c-jun as well as the average absorbency in the right frontal lobule division and right hippocampus division in the operation group were significantly higher than those in the false operation group (P < 0. 05). The number of Bax and Bcl-2-positive cells was significantly higher in the operation group, and the expression ratio of Bax/Bcl-2 in the operation group was significantly higher than that in the false operation group (P < 0.01). Conclusions: rCBF decrease can impair learning and memory function in rats, which may be related to the increased expression of c-fos, c-jun, Bcl-2, and Bax proteins in the frontal cortex and hippocampus. Citation Xu CL, Wu WH, Kong LB. Effects of regional cerebral blood flow perfusion on learning and memory function

Enzyme-treated asparagus extract (ETAS) contains various phytochemicals. It has been reported that ETAS protected early cognitive impairment of SAMP8 mice and Aβ-induced reduction of PC12 cell viability. In addition, ETAS had several functions on healthy people. The purpose of the present study was to investigate the effects of ETAS on normal memory function of rats and neurite-outgrowth of PC12 cells. ETAS significantly accelerated learning acquisition in in vivo and neurite-outgrowth in in vitro study. In conclusion, ETAS affected on memory function in early stage in normal rats. The basis of this effect may induce neurite-outgrowth in neurons.

An experiment was designed to show how immediate recall may affect recognition. A number of subjects were shown a picture. Some were asked to recall it and were then given a recognition test. Others were given only the recognition test after the same interval. Only 4 of the 16 subjects who had recalled it identified it; whereas 14 of the 16 others did so. A second experiment gave similar results. Recall was constructed round dominant items of the picture. This distribution of emphasis together with the acceptance of an invented detail as genuine were the common causes of errors in subsequent recognition. Both the dominant and invented items in recall were those which became most obviously merged into an organization of related experiences and in consequence those which militated against subsequent recognition. The recognition test was applied in two further groups of 16 subjects with a change in one of the dominant details (i.e. the wording). The number of subjects who now correctly identified the remainder of the material was 9 when there was no intermediate recall, and nil when immediate recall of the original material was interposed.

Recent developments in the study of stimulus generalization by means of operant conditioning methods require a re-examination of the problem of stimulus generalization and a review of the role of this concept in description and analysis of behavior. No final view of the outlines of learning theory can be achieved until more complete and fundamental information about generalization has been obtained. It has been established that in the pigeon orderly and reproducible bidirectional gradients can be obtained for individual Ss along the light-wavelength continuum. A dilemma is posed by the finding that these gradients are orderly on a physical scale; but not on an equal-discriminability scale. The form of the generalization function raises questions as the interpretation and meaning of the just-noticeable-difference concept. The problem of multidimensional stimulus generalization is discussed. The understanding of stimulus relationships in the generalization phenomenon is proposed as an issue of greater significance and difficulty than that of the control of generalization by such conventionally more prominent variables as drive and reinforcement.