scholarly journals Regulation of perceptual learning by chronic chemogenetic manipulation of parvalbumin-positive interneurons

2020 ◽  
Author(s):  
J. Miguel Cisneros-Franco ◽  
Maryse E. Thomas ◽  
Itri Regragui ◽  
Conor P. Lane ◽  
Lydia Ouellet ◽  
...  
Keyword(s):  
Perceptual Learning ◽  
Cell Activity ◽  
Accelerated Learning ◽  
Cell Manipulation ◽  
Neural Synchrony ◽  
Subsequent Increase ◽  
Training Performance ◽  
Pv Cell ◽  
Plastic Changes ◽  
Perceptual Acuity

AbstractParvalbumin-positive (PV+) interneurons are major regulators of adult experience-dependent plasticity. Acute manipulation of PV+ cell activity before learning alters the rate of acquisition of new skills, whereas transient inactivation of PV+ cells interferes with retrieval of previously learned information. However, the effects of sustained PV+ cell manipulation throughout training remain largely unknown. Using chemogenetics in rat auditory cortex during an adaptive sound disrimination task, here we show that PV+ cells exert bidirectional control over the rate of perceptual learning. Down-regulation of PV+ cell activity accelerated learning, but increasing their activity resulted in slower learning. However, both interventions led to reduced gains in perceptual acuity by the end of training relative to controls. Furthermore, longitudinal training performance was functionally correlated with measures of neural synchrony and stimulus-specific adaptation. These findings suggest that, whereas restricting PV+ cell activity may initially facilitate training-induced plasticity, a subsequent increase in PV+ cell activity is necessary to prevent further plastic changes and consolidate learning.

Tissue Factor Activity of Cultured Macrophages. Enhancement by Specific Antigenic Stimulation

1975 ◽  
Author(s):  
S. Beguin ◽  
A. Goutner ◽  
F. Josso
Keyword(s):  
Human Serum ◽  
Tissue Factor ◽  
Cell Activity ◽  
Cell Suspensions ◽  
Rabbit Serum ◽  
Factor Activity ◽  
Clotting System ◽  
Subsequent Increase ◽  
Macrophage Activity ◽  
Tissue Factor Activity

Peritoneal macrophage suspensions (95 p. cent pure) were obtained in rabbits either intact or previously immunized against human serum. Cell suspensions exhibited a clear tissue factor activity, closely related to the cell concentration.Macrophages (10000/mm3) were cultured in the presence of PO4)2 Ca3 adsorbed and decomplemented serum of either rabbit or human origin. Clotting activity of the supernatant medium was tested after 24 hour culture. In immunized animals, tissue factor activity was much higher when the cells were cultured in the presence of the antigens (human serum) instead of rabbit serum; no difference was observed in intact rabbits.Contamination of the cell suspensions by lymphocytes seems too low to play a role in this stimulation of macrophage activity. The reported data suggest that antibodies bound to macrophage membrane react with the medium antigens with subsequent increase of the cell activity.Such a phenomenon could initiate the activation of the clotting system observed in some immune reactions.

Distinct Requirements for Optimal Growth and In Vitro Expansion of Human CD34+CD38− Bone Marrow Long-Term Culture-Initiating Cells (LTC-IC), Extended LTC-IC, and Murine In Vivo Long-Term Reconstituting Stem Cells

Blood ◽  
1999 ◽  
Vol 94 (12) ◽  
pp. 4093-4102 ◽  
Author(s):  
Veslemøy Ramsfjell ◽  
David Bryder ◽  
Helga Björgvinsdóttir ◽  
Sten Kornfält ◽  
Lars Nilsson ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Cell Activity ◽  
Optimal Growth ◽  
Cell Manipulation ◽  
Long Term Culture ◽  
Human Cd34

Abstract Recently, primitive human bone marrow (BM) progenitors supporting hematopoiesis in extended (>60 days) long-term BM cultures were identified. Such extended long-term culture-initiating cells (ELTC-IC) are of the CD34+CD38− phenotype, are quiescent, and are difficult to recruit into proliferation, implicating ELTC-IC as the most primitive human progenitor cells detectable in vitro. However, it remains to be established whether ELTC-IC can proliferate and potentially expand in response to early acting cytokines. Here, CD34+CD38− BM ELTC-IC (12-week) were efficiently recruited into proliferation and expanded in vitro in response to early acting cytokines, but conditions for expansion of ELTC-IC activity were distinct from those of traditional (5-week) LTC-IC and murine long-term repopulating cells. Whereas c-kit ligand (KL), interleukin-3 (IL-3), and IL-6 promoted proliferation and maintenance or expansion of murine long-term reconstituting activity and human LTC-IC, they dramatically depleted ELTC-IC activity. In contrast, KL, flt3 ligand (FL), and megakaryocyte growth and development factor (MGDF) (and KL + FL + IL-3) expanded murine long-term reconstituting activity as well as human LTC-IC and ELTC-IC. Expansion of LTC-IC was most optimal after 7 days of culture, whereas optimal expansion of ELTC-IC activity required 12 days, most likely reflecting the delayed recruitment of quiescent CD34+CD38− progenitors. The need for high concentrations of KL, FL, and MGDF (250 ng/mL each) and serum-free conditions was more critical for expansion of ELTC-IC than of LTC-IC. The distinct requirements for expansion of ELTC-IC activity when compared with traditional LTC-IC suggest that the ELTC-IC could prove more reliable as a predictor for true human stem cell activity after in vitro stem cell manipulation.

Distinct Requirements for Optimal Growth and In Vitro Expansion of Human CD34+CD38− Bone Marrow Long-Term Culture-Initiating Cells (LTC-IC), Extended LTC-IC, and Murine In Vivo Long-Term Reconstituting Stem Cells

Blood ◽  
1999 ◽  
Vol 94 (12) ◽  
pp. 4093-4102 ◽  
Author(s):  
Veslemøy Ramsfjell ◽  
David Bryder ◽  
Helga Björgvinsdóttir ◽  
Sten Kornfält ◽  
Lars Nilsson ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Cell Activity ◽  
Optimal Growth ◽  
Cell Manipulation ◽  
Long Term Culture ◽  
Human Cd34

Recently, primitive human bone marrow (BM) progenitors supporting hematopoiesis in extended (>60 days) long-term BM cultures were identified. Such extended long-term culture-initiating cells (ELTC-IC) are of the CD34+CD38− phenotype, are quiescent, and are difficult to recruit into proliferation, implicating ELTC-IC as the most primitive human progenitor cells detectable in vitro. However, it remains to be established whether ELTC-IC can proliferate and potentially expand in response to early acting cytokines. Here, CD34+CD38− BM ELTC-IC (12-week) were efficiently recruited into proliferation and expanded in vitro in response to early acting cytokines, but conditions for expansion of ELTC-IC activity were distinct from those of traditional (5-week) LTC-IC and murine long-term repopulating cells. Whereas c-kit ligand (KL), interleukin-3 (IL-3), and IL-6 promoted proliferation and maintenance or expansion of murine long-term reconstituting activity and human LTC-IC, they dramatically depleted ELTC-IC activity. In contrast, KL, flt3 ligand (FL), and megakaryocyte growth and development factor (MGDF) (and KL + FL + IL-3) expanded murine long-term reconstituting activity as well as human LTC-IC and ELTC-IC. Expansion of LTC-IC was most optimal after 7 days of culture, whereas optimal expansion of ELTC-IC activity required 12 days, most likely reflecting the delayed recruitment of quiescent CD34+CD38− progenitors. The need for high concentrations of KL, FL, and MGDF (250 ng/mL each) and serum-free conditions was more critical for expansion of ELTC-IC than of LTC-IC. The distinct requirements for expansion of ELTC-IC activity when compared with traditional LTC-IC suggest that the ELTC-IC could prove more reliable as a predictor for true human stem cell activity after in vitro stem cell manipulation.

Development of cytochrome P450 17α-hydroxylase (P450c17) mRNA and enzyme activity in neonatal ovaries of normal and hypogonadal (hpg) mice

1996 ◽  
Vol 17 (1) ◽  
pp. 55-60 ◽  
Author(s):  
S A Gray ◽  
M A Mannan ◽  
P J O'Shaughnessy
Keyword(s):  
Enzyme Activity ◽  
Cytochrome P450 ◽  
Cell Activity ◽  
Subsequent Development ◽  
Interstitial Tissue ◽  
Cytochrome P450 Enzyme ◽  
Mrna Levels ◽  
Subsequent Increase ◽  
Androgen Synthesis ◽  
P450 Enzyme

ABSTRACT The cytochrome P450 enzyme 17α-hydroxylase (P450c17) is required for androgen synthesis and therefore regulates substrate supply for aromatization. In this study, changes in P450c17 activity and mRNA levels were measured during ovarian development in the normal mouse and in the hypogonadal (hpg) mouse which lacks circulating gonadotrophins. At birth, low levels of P450c17 activity and mRNA were detectable in normal ovaries. This basal level of expression did not change until after day 10 at which time both enzyme activity and mRNA levels increased by six- to eightfold. In the hpg mouse, levels of P450c17 mRNA were normal at birth but did not change significantly during subsequent development and were significantly less than normal by day 15. Results show that there is a low level of gonadotrophin-independent expression of P450c17 in the ovary at birth and that gonadotrophins are required for the subsequent increase in expression between days 10 and 15. In the ovary, P450c17 is expressed solely in the thecal/interstitial compartment and interstitial cells arise in the mouse ovary around day 11. Changes in P450c17 are likely, therefore, to be related to gonadotrophin-dependent development of the interstitial tissue in the mouse. Treatment of adult hpg mice with LH and FSH showed that both gonadotrophins can act to increase P450c17 activity. Since FSH acts only on the granulosa cell compartment of the ovary it is likely that FSH acts through a paracrine mechanism to regulate thecal/interstitial cell activity.

Age-Related Effects of Stimulus-Specific Context on Perceptual Learning

1988 ◽  
Vol 32 (3) ◽  
pp. 198-202
Author(s):  
Wendy A. Rogers ◽  
Arthur D. Fisk
Keyword(s):  
Older Adults ◽  
Perceptual Learning ◽  
Specific Training ◽  
Training Performance ◽  
Old Adults ◽  
Age Related ◽  
Varied Mapping ◽  
Similar Information ◽  
Consistent Mapping ◽  
Context Specific

The focus of the present study was the investigation of age-related differences in perceptual learning under conditions of consistent mapping (CM), varied mapping (VM), and context-specific training. Context-specific training involved conditions where specific target and distractor sets were paired consistently within a condition but were inconsistent across conditions. Eight young (mean age 25) and eight old (mean age 67) subjects participated for 8000 trials of training and 3200 trials of various transfer conditions. The transfer conditions were designed to ascertain the extent to which the subjects had automatized their performance in each of the training conditions. The training results yielded significant differences between young and old adults only under CM training. Performance in the context conditions for young adults mimicked that of the old subjects in the CM condition. The training results suggest that manipulations which disrupt the development of attention-calling strength of stimuli lead to equivalent performance for young and old adults. The transfer results provide similar information. It is proposed that the ability to “strengthen” target information is disrupted in older adults. Based on our previous and the present findings, processing principles are presented which outline important differential considerations for training young and/or older adults.

Perceptual Learning of Vocoded Speech With and Without Contralateral Hearing: Implications for Cochlear Implant Rehabilitation

2020 ◽  
pp. 1-10
Author(s):  
Martin Chavant ◽  
Alexis Hervais-Adelman ◽  
Olivier Macherey
Keyword(s):  
Cochlear Implant ◽  
Perceptual Learning ◽  
Speech Signal ◽  
Training Phase ◽  
Monosyllabic Words ◽  
Low Pass ◽  
Contralateral Ear ◽  
Number Of Individuals ◽  
Insight Into ◽  
Vocoded Speech

Purpose An increasing number of individuals with residual or even normal contralateral hearing are being considered for cochlear implantation. It remains unknown whether the presence of contralateral hearing is beneficial or detrimental to their perceptual learning of cochlear implant (CI)–processed speech. The aim of this experiment was to provide a first insight into this question using acoustic simulations of CI processing. Method Sixty normal-hearing listeners took part in an auditory perceptual learning experiment. Each subject was randomly assigned to one of three groups of 20 referred to as NORMAL, LOWPASS, and NOTHING. The experiment consisted of two test phases separated by a training phase. In the test phases, all subjects were tested on recognition of monosyllabic words passed through a six-channel “PSHC” vocoder presented to a single ear. In the training phase, which consisted of listening to a 25-min audio book, all subjects were also presented with the same vocoded speech in one ear but the signal they received in their other ear differed across groups. The NORMAL group was presented with the unprocessed speech signal, the LOWPASS group with a low-pass filtered version of the speech signal, and the NOTHING group with no sound at all. Results The improvement in speech scores following training was significantly smaller for the NORMAL than for the LOWPASS and NOTHING groups. Conclusions This study suggests that the presentation of normal speech in the contralateral ear reduces or slows down perceptual learning of vocoded speech but that an unintelligible low-pass filtered contralateral signal does not have this effect. Potential implications for the rehabilitation of CI patients with partial or full contralateral hearing are discussed.

571: Importance of the Intracrine Metabolism of Adrenal Androgens in Androgen Dependent Prostate Cancer Cell Activity

2005 ◽  
Vol 173 (4S) ◽  
pp. 156-156
Author(s):  
Kazuya Suzuki ◽  
Tsutomu Nishiyama ◽  
Noboru Hara ◽  
Vladimir Bilim ◽  
Kazutoshi Yamana ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cell ◽  
Prostate Cancer Cell ◽  
Cell Activity ◽  
Adrenal Androgens

Predictive Validity of a Selection Procedure for Air Traffic Controller Trainees

2013 ◽  
Vol 3 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Yvonne Pecena ◽  
Doris Keye ◽  
Kristin Conzelmann ◽  
Dietrich Grasshoff ◽  
Peter Maschke ◽  
...  
Keyword(s):  
Predictive Validity ◽  
Selection Procedure ◽  
Air Traffic ◽  
Performance Criteria ◽  
Training Phase ◽  
Air Traffic Controller ◽  
Training Performance ◽  
Navigation Service ◽  
German Aerospace ◽  
Training Success

The job of an air traffic controller (ATCO) is very specific and demanding. The assessment of potential suitable candidates requires a customized and efficient selection procedure. The German Aerospace Center DLR conducts a highly selective, multiple-stage selection procedure for ab initio ATCO applicants for the German Air Navigation Service Provider DFS. Successful applicants start their training with a training phase at the DFS Academy and then continue with a unit training phase in live traffic. ATCO validity studies are scarcely reported in the international scientific literature and have mainly been conducted in a military context with only small and male samples. This validation study encompasses the data from 430 DFS ATCO trainees, starting with candidate selection and extending to the completion of their training. Validity analyses involved the prediction of training success and several training performance criteria derived from initial training. The final training success rate of about 79% was highly satisfactory and higher than that of other countries. The findings demonstrated that all stages of the selection procedure showed predictive validity toward training performance. Among the best predictors were scores measuring attention and multitasking ability, and ratings on general motivation from the interview.

Sign in / Sign up

Export Citation Format

Share Document