Mild maternal separation in mice of both sexes: impact in adultthood on vigor to approach or to escape motivational stimuli and interaction with dopamine depletion

Treball Final de Màster Universitari en Investigació en Cervell i Conducta. Codi: SBM024. Curs: 2019/2020.Early-life stress affects brain development and can lead to psychiatric disorders such as depression later in life. Little is known about the effect of early-life stress on motivational processes such as effort-based decision-making, which could be impaired in people with depression. Mesolimbic dopamine (DA) regulates behavioral activation and effort in motivated behaviors, and stress produces opposite effects on DA release depending if it is acute or chronic. Maternal Separation (MS) could act as an early-life stressor depending on its duration and intensity. Using CD1 male and female mice, we evaluate the impact of early but mild MS (PND3-5, 90 min), on selection of effortful responses in adulthood under positive or aversive conditions. In a three-choice-T-maze, mice preference for active reinforcers such as a running wheel (RW) versus sedentary ones was evaluated, and in a forced swim task (FST), time dedicated to escape or passively floating was measured. In addition, we studied if MS interacts with DA depletion in adulthood, administering tetrabenazine (TBZ), a VMAT-2 inhibitor that induces fatigue and anergia. Males and females do not differ; they spend more time in the RW and less eating or sniffing a neutral odor in the T-maze, independently of separation. However, separated mice of both sexes spent more time in the RW, and climbing in the FST compared to non-separated mice. Only among males, TBZ reduced time in RW, increased time eating, reduced climbing and increased immobility. Females were not affected by DA depletion. Anxiety was evaluated in a dark-light box, and separated males where less anxious than non-separated, but TBZ did not affect either sex

Clustering and phase behaviour of attractive active particles with hydrodynamics

We simulate clustering, phase separation and hexatic ordering in a monolayered suspension of active squirming disks subject to an attractive Lennard-Jones-like pairwise interaction potential, taking hydrodynamic interactions between the particles fully into account. By comparing the hydrodynamic case with counterpart simulations for passive and active Brownian particles, we elucidate the relative roles of self-propulsion, interparticle attraction, and hydrodynamic interactions in determining clustering and phase behaviour. Even in the presence of an attractive potential, we find that hydrodynamic interactions strongly suppress the motility induced phase separation that might a priori have been expected in a highly active suspension. Instead, we find only a weak tendency for the particles to form stringlike clusters in this regime. At lower activities we demonstrate phase behaviour that is broadly equivalent to that of the counterpart passive system at low temperatures, characterized by regimes of gas–liquid, gas–solid and liquid–solid phase coexistence. In this way, we suggest that a dimensionless quantity representing the level of activity relative to the strength of attraction plays the role of something like an effective non-equilibrium temperature, counterpart to the (dimensionless) true thermodynamic temperature in the passive system. However there are also some important differences from the equilibrium case, most notably with regards the degree of hexatic ordering, which we discuss carefully

Optimum power allocation and bit loading for BICM systems

This paper introduces a joint bit loading and power allocation algorithm for systems combining bit-interleaved coded modulation (BICM) with multicarrier transmission. The proposed algorithm maximizes the mutual information, so it can be regarded as a generalization of mercury/waterfilling policy that incorporates bit loading. The followed approach relies on irregular modulation and power to cast the problem in the framework of convex optimization. This allows to derive the optimum solution without resorting to greedy algorithms, embedding the bit loading in the definition of an equivalent constellation such that the complexity increase with respect to mercury/waterfilling is negligible. While irregular modulation plays a key role in algorithm definition, it is proved that only a few subcarriers employ it and it is shown that a practical low complexity algorithm can be obtained with minimal losses that does not use irregular modulation.Peer ReviewedPostprint (published version

Optimum power allocation and bit loading with code rate constraints

In this paper, a new power allocation and bit loading policy is defined for those systems working with a preselected binary channel code and specific bit error rate (BER) requirements. It consists on the maximization of the spectral efficiency with a constraint on the average mutual information per coded bit (bit MI), exploiting the relationship of the bit MI with the BER and the code rate. An irregular modulation approach is employed in order to express the policy as a convex optimization problem, solved without the need of greedy algorithms. Results are compared with those obtained with other algorithms in the literature.Postprint (published version

Non-linear graph-based codes for joint source-channel coding

We study the behavior of a new family of nonlinear graph-based codes, previously introduced for compression of asymmetric binary memoryless sources, for the joint source-channel coding scenario in which the codewords are transmitted through an additive white Gaussian noise channel. We focus on low entropy sources (with high redundancy) and compression rates. Monte Carlo simulation and density evolution results show that the proposed family, with a regular and simple parametrization of the degree profiles, outperforms linear codes.Peer ReviewedPostprint (published version

Adaptive sampling for fast sparsity pattern recovery

In this paper we propose a low complexity adaptive algorithm for lossless compressive sampling and reconstruction of sparse signals. Consider a sparse non-negative real signal x containing only k << n non-zero values. The sampling process obtains m measurements by a linear projection y = Ax and, in order to minimize the complexity, we quantize them to binary values. We also define the measurement matrix A to be binary and sparse, enabling the use of a simple message passing algorithm over a graph. We show how to adaptively construct this matrix in a multi-stage process that sequentially reduces the search space until the sparsity pattern is perfectly recovered. As verified by simulation results, the process requires O(n) operations and O(k log(n/k)) samplesPeer ReviewedPostprint (published version

Sex and age differences in mice models of effort-based decision-making and anergia in depression : the role of dopamine, and cerebral-dopamine-neurotrophic-factor

Mesolimbic dopamine (DA) regulates vigor in motivated behavior. While previous results have mainly been performed in male rodents, the present studies compared CD1 male and female mice in effort-based decision-making tests of motivation. These tests offered choices between several reinforcers that require different levels of effort (progressive ratio/choice task and 3-choice-T-maze task). Sweet reinforcers were used in both tasks. In the operant tasks, females worked harder as the task required more effort to access a 10% sucrose solution. Although males and females did not differ in preference for 10% vs 3% solutions under free concurrent presentation, females consumed more of the 10% solution when tested alone. The operant task requires a long period of training and changes in the DA system due to age can be mediating long-term changes in effort. Thus, age and sex factors were evaluated in the T-maze task, which requires only a short training period. Both sexes and ages were equally active when habituated to the running wheel (RW), but females consumed more sweet pellets than males, especially at an older age. Both sexes had a strong preference for the RW compared to more sedentary reinforcers in the 3-choice-T-maze test, but older animals spent less time running and ate more than the young ones. The DA-depleting agent tetrabenazine reduced time running in older mice but not in adolescents. Cerebral-dopamine-neurotrophic-factor was reduced in older mice of both sexes compared to adolescent mice. These results emphasize the importance of taking into account differences in sex and age when evaluating willingness to exert effort for specific reinforcers.Funding for open access charge: CRUE-Universitat Jaume

Relationship between D90 and D100 with Biochemical and Local Failure in Low-risk Prostate Cancer Treated with Low-rate Brachytherapy (LDR)

Low dose rate brachytherapy (LDR) is an accepted, effective treatment with few local side effects, used as monotherapy in patients with low-risk prostate cancer (PC). The aim of this paper is to analyse 245 patients treated with LDR in the Radiation Oncology Department of the Hospital Gómez Ulla, from 2004 to 2016, evaluating the relationship of dosimetric parameters with biochemical and local recurrence as well as genitourinary and gastrointestinal toxicity derived from the technique. The results obtained show a clear relationship between the dose used and biochemical and local failure