Spatial learning and memory in the tortoise (Geochelone carbonaria)

A single tortoise (Geochelone carbonaria) was trained in an eight-arm radial maze, with the apparatus and general procedures modeled on those used to demonstrate spatial learning in rats. The tortoise learned to perform reliably above chance, preferentially choosing baited arms, rather than returning to arms previously visited on a trial. Test sessions that examined control by olfactory cues revealed that they did not affect performance. No systematic, stereotyped response patterns were evident. In spite of differences in brain structure, the tortoise showed spatial learning abilities comparable to those observed in mammals

Reported Earnings and Analyst Forecasts as Competing Sources of Information: A New Approach

We study information flows between earnings and forecasts, using suitably adapted Granger causality tests. This approach complements existing cross-sectional studies by abstracting from stock market reactions to information, and focussing on dynamic interactions between information flows instead. We find bi-directional causality in timeseries of analyst earnings forecasts and reported earnings, supporting our expectation that forecasts contribute to information that is reflected in future reports. Further, our evidence of feedback suggests that past reports and forecasts are both reflected in future forecasts, implying that the information in reports has inherent value, and that forecasts do not fully substitute for reports.

A validation study of a smartphone application for functional mobility assessment of the elderly

AbstractBackgroundTo minimize the reaction time and position judgment error using stopwatch-timed measures, we developed a smartphone application to measure performance in the five-time sit-to-stand (FTSTS) and timed up-and-go (TUG) tests.ObjectiveThis study aimed to validate this smartphone application by comparing its measurement with a laboratory-based reference condition.MethodsThirty-two healthy elderly people were asked to perform the FTSTS and TUG tests in a randomized sequence. During the tests, their performance was concurrently measured by the smartphone application and a force sensor installed in the backrest of a chair. The intraclass correlation coefficient [ICC(2,1)] and Bland–Altman analysis were used to calculate the measurement consistency and agreement, respectively, between these two methods.ResultsThe smartphone application demonstrated excellent measurement consistency with the lab-based reference condition for the FTSTS test [ICC(2,1) = 0.988] and TUG test [ICC(2,1) = 0.946]. We observed a positive bias of 0.27 seconds (95% limits of agreement, −1.22 to 1.76 seconds) for the FTSTS test and 0.48 seconds (95% limits of agreement, −1.66 to 2.63 seconds) for the TUG test.ConclusionWe cross-validated the newly developed smartphone application with the laboratory-based reference condition during the examination of FTSTS and TUG test performance in healthy elderly

Acetylcholine Contributes to Head Direction Cell Stability During Path Integration and Landmark Navigation

Perceived directional heading is represented in the brain by head direction (HD) cells, which fire rapidly when the head is pointed in one direction and become virtually silent when the head is pointed in all other directions. The HD signal is dominantly controlled by the position of visual landmarks, but can be maintained by path integration when familiar landmarks are not available. The neural mechanism(s) that allow path integration to maintain the HD signal have not been investigated, but a possible component of this mechanism is acetylcholine, given that selective cholinergic lesions impair path integration-based navigation. To test this, we recorded HD cell activity from the anterodorsal thalamus while rats foraged for food within a cylinder, or navigated within a dual chamber apparatus, after systemic injection of saline or atropine sulfate. In the cylinder, a prominent cue card served as the sole landmark for a standard session, after which the cue was removed for a no-cue session. Saline or atropine sulfate was then injected, and a second no-cue session was conducted, followed by standard, 90° cue rotation, standard, and no-cue sessions. During the first no-cue session after injection, some cells in atropine-treated rats showed slightly more drift in preferred firing direction (PFD) than control cells, but otherwise appeared to be unaffected by atropine. With the cue rotated 90º, 10 of the 19 (53%) cells in atropine-treated rats and 12 of the 17 (71%) control cells shifted within ± 30° of 90º. In the dual chamber apparatus, rats walked from a familiar cylinder to a novel rectangle via an alleyway, and then returned to the familiar cylinder. Control HD cells (n = 7) showed a slight PFD shift as the rat entered the novel rectangle (mean absolute shift = 17.14 ± 3.80°, range = -30 to 12°), suggesting the HD signal was maintained relatively well between arenas by path integration; upon return, the PFD returned to that of the first session (mean absolute shift = 5.14 ± 1.56°, range = -12 to 6°). In contrast, 7 of the 9 HD cells in atropine-treated rats (78%) showed greater PFD shifts between the familiar cylinder and novel rectangle (mean absolute shift = 86.00 ± 12.17°, angular shift range = -102 to 114°) and between the first and last sessions in the familiar cylinder (mean absolute shift = 24.00 ± 10.16°, angular shift range = 0 to -72°); 2 of the 9 cells (22%) showed considerable PFD drift during the novel rectangle or return cylinder sessions. Thus, acetylcholine is not critical for normal HD cell activity within a familiar environment, but facilitates the stability of the HD signal during both path integration and landmark navigation

Commodity prices rise sharply at turning points

Commodity prices depend on supply and demand. With an uneven distribution of resources, prices are high at locations starved of commodity and low where it is abundant. We introduce an agent-based model in which agents set their prices to maximize profit. At steady state, the market self-organizes into three groups: excess producers, consumers, and balanced agents. When resources are scarce, prices rise sharply at a turning point due to the disappearance of excess producers. Market data of commodities provide evidence of turning points for essential commodities, as well as a yield point for non-essential ones

The association of cognitive and somatic depressive symptoms with depression recognition and outcomes after myocardial infarction

BACKGROUND: Among patients with acute myocardial infarction (AMI), depression is both common and under-recognized. The association of different manifestations of depression, somatic and cognitive, with depression recognition and long-term prognosis is poorly understood. METHODS AND RESULTS: Depression was confirmed in 481 AMI patients enrolled from 21 sites during their index hospitalization with a Patient Health Questionnaire (PHQ-9) score ≥10. Within the PHQ-9, separate somatic and cognitive symptom scores were derived and the independent association between these domains and the clinical recognition of depression, as documented in the medical records, was evaluated. In a separate multisite AMI registry of 2,347 patients, the association between somatic and cognitive depressive symptoms and 4-year all-cause mortality and 1-year all-cause rehospitalization was evaluated. Depression was clinically recognized in 29% (n=140) of patients. Cognitive depressive symptoms (Relative Risk [RR] per Standard Deviation [SD] increase=1.14; 95% confidence interval [CI] 1.03–1.26; p=0.01) were independently associated with depression recognition, while the association for somatic symptoms and recognition (RR=1.04; 95% CI 0.87–1.26; p=0.66) was not significant. However, unadjusted Cox regression analyses found that only somatic depressive symptoms were associated with 4-year mortality (Hazard Ratio [HR] per SD increase=1.22; 95% confidence interval [CI] 1.08–1.39) or 1-year rehospitalization (HR=1.22; 95%CI 1.11–1.33) while cognitive manifestations were not (HR for mortality=1.01; 95%CI 0.89–1.14; HR for rehospitalization=1.01; 95%CI 0.93–1.11). After multivariable adjustment, the association between somatic symptoms and rehospitalization persisted (HR=1.16; 95% CI:1.06–1.27; p=0.01) but was attenuated for mortality (HR=1.07; 95% CI:0.94–1.21; p=0.30). CONCLUSIONS: Depression after AMI was recognized in fewer than 1 in 3 patients. Although cognitive symptoms were associated with recognition of depression, somatic symptoms were associated with long-term outcomes. Comprehensive screening and treatment of both somatic and cognitive symptoms may be necessary to optimize depression recognition and treatment in AMI patients

Fuzzy entropy based nonnegative matrix factorization for muscle synergy extraction

The concept of muscle synergies has proven to be an effective method for representing patterns of muscle activation. The number of degrees of freedom to be controlled are reduced while also providing a flexible platform for producing detailed movements using synergies as building blocks. It has previously been shown that small components of movement are crucial to producing precise and coordinated movement. Methods which focus on the variance of the data make it possible to overlook these small components in the synergy extraction process. However, algorithms which address the inherent complexity in the neuromuscular system are lacking. To that end we propose a new nonnegative matrix factorization algorithm which employs a cross fuzzy entropy similarity measure, thus, extracting muscle synergies which preserve the complexity of the recorded muscular data. The performance of the proposed algorithm is illustrated on representative EMG data

Toll-like receptor-4 null mutation causes fetal loss and fetal growth restriction associated with impaired maternal immune tolerance in mice.

Maternal immune adaptation to accommodate pregnancy depends on sufficient availability of regulatory T (Treg) cells to enable embryo implantation. Toll-like receptor 4 is implicated as a key upstream driver of a controlled inflammatory response, elicited by signals in male partner seminal fluid, to initiate expansion of the maternal Treg cell pool after mating. Here, we report that mice with null mutation in Tlr4 (Tlr4-/-) exhibit impaired reproductive outcomes after allogeneic mating, with reduced pregnancy rate, elevated mid-gestation fetal loss, and fetal growth restriction, compared to Tlr4+/+ wild-type controls. To investigate the effects of TLR4 deficiency on early events of maternal immune adaptation, TLR4-regulated cytokines and immune regulatory microRNAs were measured in the uterus at 8 h post-mating by qPCR, and Treg cells in uterus-draining lymph nodes were evaluated by flow cytometry on day 3.5 post-coitum. Ptgs2 encoding prostaglandin-endoperoxide synthase 2, cytokines Csf2, Il6, Lif, and Tnf, chemokines Ccl2, Cxcl1, Cxcl2, and Cxcl10, and microRNAs miR-155, miR-146a, and miR-223 were induced by mating in wild-type mice, but not, or to a lesser extent, in Tlr4-/- mice. CD4⁺ T cells were expanded after mating in Tlr4+/+ but not Tlr4-/- mice, with failure to expand peripheral CD25⁺FOXP3⁺ NRP1⁻ or thymic CD25⁺FOXP3⁺ NRP1⁺ Treg cell populations, and fewer Treg cells expressed Ki67 proliferation marker and suppressive function marker CTLA4. We conclude that TLR4 is an essential mediator of the inflammation-like response in the pre-implantation uterus that induces generation of Treg cells to support robust pregnancy tolerance and ensure optimal fetal growth and survival.Hon Y. Chan, Lachlan M. Moldenhauer, Holly M. Groome, John E. Schjenken, Sarah A. Robertso