scholarly journals Overnight memory consolidation facilitates rather than interferes with new learning of similar materials - a study probing NMDA-receptors

2017 ◽  
Author(s):  
Asfestani M Alizadeh ◽  
E Braganza ◽  
J Schwidetzky ◽  
J Santiago ◽  
S Soekadar ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Time Dependent ◽  
Similar Material ◽  
Double Blind ◽  
Memory Integration ◽  
New Learning ◽  
Similar Materials ◽  
Cue Words ◽  
Enhanced Learning ◽  
Healthy Participants

AbstractWhereas sleep-dependent consolidation and its neurochemical underpinnings have been strongly researched, less is known about how consolidation during sleep affects subsequent learning. Since sleep enhances memory, it can be expected to pro-actively interfere with learning after sleep, in particular of similar materials. This pro-active interference should be enhanced by substances that benefit consolidation during sleep, such as D-cycloserine. We tested this hypothesis in two groups (Sleep, Wake) of young healthy participants receiving on one occasion D-cycloserine (175 mg) and on another occasion placebo, according to a double-blind balanced cross-over design. Treatment was administered after participants had learned a set of word-pairs (A-B list) and before nocturnal retention periods of sleep vs. wakefulness. After D-cycloserine blood plasma levels had dropped to negligible amounts, i.e., the next day in the evening, participants learned, in three sequential runs, new sets of word-pairs. One list – to enhance interference – consisted of the same cue words as the original set paired with a new target word (A-C list) and the other of completely new cue words (D-E set). Unexpectedly, during post-retention learning the A-C interference list was generally better learned than the completely new D-E list, which suggests that consolidation of previously encoded similar material enhances memory integration rather than pro-active interference. Consistent with this view, new learning of word-pairs was better after sleep than wakefulness. Similarly, D-cycloserine generally enhanced learning of new word-pairs, compared to placebo. This effect being independent of sleep or wakefulness, leads us to speculate that D-cycloserine, in addition to enhancing sleep-dependent consolidation, might mediate a time-dependent process of active forgetting.

scholarly journals Overnight memory consolidation facilitates rather than interferes with new learning of similar materials—a study probing NMDA receptors

2018 ◽  
Vol 43 (11) ◽  
pp. 2292-2298 ◽  
Author(s):  
M. Alizadeh Asfestani ◽  
E. Braganza ◽  
J. Schwidetzky ◽  
J. Santiago ◽  
S. Soekadar ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Memory Consolidation ◽  
New Learning ◽  
Similar Materials

Class I HDAC inhibition improves object recognition memory consolidation through BDNF/TrkB pathway in a time-dependent manner

2021 ◽  
Vol 187 ◽  
pp. 108493
Author(s):  
Gerardo Ramirez-Mejia ◽  
Elvi Gil-Lievana ◽  
Oscar Urrego-Morales ◽  
Ernesto Soto-Reyes ◽  
Federico Bermúdez-Rattoni
Keyword(s):  
Object Recognition ◽  
Recognition Memory ◽  
Memory Consolidation ◽  
Time Dependent ◽  
Class I ◽  
Dependent Manner ◽  
Hdac Inhibition ◽  
Object Recognition Memory

scholarly journals GABA Supplementation Negatively Affects Cognitive Flexibility Independent of Tyrosine

2021 ◽  
Vol 10 (9) ◽  
pp. 1807
Author(s):  
Lee Wei Lim ◽  
Luca Aquili
Keyword(s):  
Cognitive Flexibility ◽  
Task Switching ◽  
Animal Studies ◽  
Preliminary Evidence ◽  
Interactive Effects ◽  
Dopamine Synthesis ◽  
Double Blind ◽  
Performance Improvements ◽  
Two Measures ◽  
Healthy Participants

Increasing evidence, particularly from animal studies, suggests that dopamine and GABA are important modulators of cognitive flexibility. In humans, increasing dopamine synthesis through its precursor tyrosine has been shown to result in performance improvements, but few studies have reported the effects of GABA supplementation in healthy participants. We conducted a double-blind, placebo-controlled, randomized experiment to test the interactive effects of tyrosine and GABA administration on two measures of cognitive flexibility, response inhibition and task switching. A total of 48 healthy volunteers were split into four groups (placebo, tyrosine alone, GABA alone, and tyrosine and GABA combined). They completed cognitive flexibility tasks at baseline and after drug administration. We found that tyrosine alone had no impact on the measures of cognitive flexibility, whereas GABA alone and in combination with tyrosine worsened task switching. Our results provide preliminary evidence that putative increases in GABA and dopamine synthesis do not interact to affect cognitive flexibility performance.

The Study on the Ratio of Similar Material in Landslide Model Test

2011 ◽  
Vol 261-263 ◽  
pp. 1679-1684
Author(s):  
Xiao Ling Liu ◽  
Shi Mei Wang ◽  
Yun Zhi Tan ◽  
Xin Jiang Hu ◽  
Dai Peng Zhao
Keyword(s):  
Model Test ◽  
Influence Factors ◽  
Deformation Modulus ◽  
High Strength ◽  
Similar Material ◽  
Talcum Powder ◽  
Angle Of Internal Friction ◽  
Similar Materials ◽  
Mixed Material ◽  
Landslide Model

The choice of similar materials and the design of mix proportions is a key step in landslide model test. On the basis of experiment, we conduct a research for the similar materials which may sufficing volume weight, cohesive force, angle of internal friction, deformation modulus, and the infiltration coefficient on the same time. Then we put forward two kinds of schemes: one is the mixed material of high-strength glass micro beads and talcum powder; the other is the mixed material of lead beads, river sands, rubber powder and talcum powder. By analyzing the result of mix proportions test, We concluded the regularity that similar index varies along with different content of the similar material ingredients and found the notable influence factors , which provides important reference for the components of similar materials in the landslide model test.

scholarly journals Experimental Study on the Ratio of Similar Materials in Weak Surrounding Rock Based on Orthogonal Design

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Jiao ◽  
Xiao Zhang ◽  
Xinzhi Li ◽  
Bohong Liu ◽  
Haojie Zhang
Keyword(s):  
Model Test ◽  
Orthogonal Design ◽  
Surrounding Rock ◽  
Similar Material ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Geological Conditions ◽  
Key Factor ◽  
Similar Materials ◽  
Weak Surrounding Rock

In the aspect of stability analysis of tunneling engineering, geomechanical model test is an important research method. A similar material is the prerequisite for the success of geomechanical model test. In the field of major engineering applications, a variety of similar materials are prepared for different geological conditions of surrounding rock and applied in some major engineering. With the use of standard sand, fine sand, and silt clay as materials, similar materials for weak surrounding rock were developed. Based on the orthogonal design method, through the direct shear test, the range analysis and variance analysis of various factors affecting the physical and mechanical parameters of weak surrounding rock are carried out. The results show similar material can meet the requirements in weak surrounding rock. Standard sand is the key factor that influences the internal friction angle of similar materials, and silt clay is the key factor affecting the cohesion of similar materials. Similar materials can meet the elastic modulus and severe requirements of the weak surrounding rock and can be used for the weak surrounding rock engineering. The new type of similar material configuration is widely used in shallow buried tunnel entrance section and urban shallow buried excavation engineering, in addition to tunnel engineering in loess stratum, and the problems of engineering design and construction are solved through geomechanical model test.

Cholecystokinin and satiety: effect of hypothalamic obesity and gastric bubble insertion

1992 ◽  
Vol 262 (2) ◽  
pp. R241-R244
Author(s):  
M. G. Boosalis ◽  
N. Gemayel ◽  
A. Lee ◽  
G. A. Bray ◽  
L. Laine ◽  
...  
Keyword(s):  
Gastric Volume ◽  
Time Dependent ◽  
Dependent Manner ◽  
Hypothalamic Obesity ◽  
Double Blind ◽  
Afferent Fibers ◽  
Hypothalamic Injury ◽  
Obese Subjects ◽  
Vagal Afferent ◽  
Gastric Bubble

Cholecystokinin (CCK) is a gut peptide whose proposed effect on satiety is thought to be related to gastric volume and to be signaled through vagal afferent fibers to the medial hypothalamus. To test these hypotheses we infused CCK C-terminal octapeptide (CCK-8) or saline in a random double-blind fashion in three groups of subjects: 17 obese subjects, 6 of whom subsequently received a gastric bubble, and 5 obese subjects whose obesity was due to hypothalamic injury. The number of sandwich canapes eaten after saline or CCK-8 infusion was recorded during three consecutive 10-min eating periods. Each subject served as his/her own control. The prior infusion of CCK-8 significantly decreased the consumption of sandwich canapes in the first eating period in both the control obese subjects and the subjects with obesity due to hypothalamic injury. Insertion of a gastric bubble did not enhance the satiety effect of CCK-8. These studies support the hypothesis that CCK produces satiety in a time-dependent manner that is not enhanced after the insertion of a gastric bubble but is operative in obese subjects with hypothalamic injury.

Arterial Stiffness Responses to Prolonged Sitting Combined with a High Glycemic Index Meal: A Double-Blind, Randomized Cross-Over Trial

2021 ◽  
Author(s):  
Elizabeth Kelsch ◽  
Jake C. Diana ◽  
Kathryn Burnet ◽  
Erik D. Hanson ◽  
Simon F. Fryer ◽  
...  
Keyword(s):  
Arterial Stiffness ◽  
Glycemic Index ◽  
Mixed Models ◽  
Disease Risk ◽  
Cardiovascular Disease Risk ◽  
Vascular Health ◽  
Double Blind ◽  
Prolonged Sitting ◽  
Healthy Participants ◽  
Low Glycemic Index

Regular exposure to uninterrupted prolonged sitting and the consumption of high glycemic meals (HGI) is independently associated with increased cardiovascular disease risk. Sitting for as little as 1-hour can impair the health of both peripheral and central arteries. However, it is currently unknown whether combined acute exposure to uninterrupted prolonged sitting and a HGI meal is more detrimental to global (peripheral and central) vascular health. The purpose of this study was to investigate the effect of prolonged sitting (3 hours), following the consumption of a HGI or low glycemic index (LGI) meal, on global pulse wave velocity (G-PWV). METHODS: Eighteen healthy participants (70% female, mean standard deviation [SD] age: 22.6 [3.1] years old, BMI: 25.5 [6.1] kg/m2) sat for 3 hours after consuming a HGI or LGI meal. G-PWV was assessed by incorporating three PWV measures (carotid-femoral, brachial-femoral, femoral-ankle). The effects of time (PRE vs. POST) and condition (LGI vs. HGI) were analyzed using linear mixed models. RESULTS: Following prolonged sitting, G-PWV increased by 0.29 m/s (i.e., PRE vs. POST). However, the condition (P=0.987) and time x condition (P=0.954) effects were non-significant. DISCUSSION: The current findings support previous research showing an increase in arterial stiffness with prolonged sitting. However, in young and healthy adults, the arterial stiffness response was not worsened through HGI consumption.

scholarly journals Resistant starch supplementation increases crypt cell proliferative state in the rectal mucosa of older healthy participants

2020 ◽  
Vol 124 (4) ◽  
pp. 374-385
Author(s):  
Fiona C. Malcomson ◽  
Naomi D. Willis ◽  
Iain McCallum ◽  
Long Xie ◽  
Arthur C. Ouwehand ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Resistant Starch ◽  
Dietary Intervention ◽  
Controlled Trial ◽  
Rectal Mucosa ◽  
Crypt Cell ◽  
Post Intervention ◽  
Double Blind ◽  
Healthy Participants

AbstractThere is strong evidence that foods containing dietary fibre protect against colorectal cancer, resulting at least in part from its anti-proliferative properties. This study aimed to investigate the effects of supplementation with two non-digestible carbohydrates, resistant starch (RS) and polydextrose (PD), on crypt cell proliferative state (CCPS) in the macroscopically normal rectal mucosa of healthy individuals. We also investigated relationships between expression of regulators of apoptosis and of the cell cycle on markers of CCPS. Seventy-five healthy participants were supplemented with RS and/or PD or placebo for 50 d in a 2 × 2 factorial design in a randomised, double-blind, placebo-controlled trial (the Dietary Intervention, Stem cells and Colorectal Cancer (DISC) Study). CCPS was assessed, and the expression of regulators of the cell cycle and of apoptosis was measured by quantitative PCR in rectal mucosal biopsies. SCFA concentrations were quantified in faecal samples collected pre- and post-intervention. Supplementation with RS increased the total number of mitotic cells within the crypt by 60 % (P = 0·001) compared with placebo. This effect was limited to older participants (aged ≥50 years). No other differences were observed for the treatments with PD or RS as compared with their respective controls. PD did not influence any of the measured variables. RS, however, increased cell proliferation in the crypts of the macroscopically-normal rectum of older adults. Our findings suggest that the effects of RS on CCPS are not only dose, type of RS and health status-specific but are also influenced by age.

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