The automatic recording of aggression in pigeons: A comparison of two methods with live targets

Three pigeons were exposed to a fixed-time response independent food-delivery schedule and a live target pigeon restrained in a holder mounted on a spring and microswitch assembly. This common method of recording aggression was compared with a photocell system, and both were evaluated by observation of video-tape recordings. Dependent variables included the number of interfood intervals with an attack, attacks per minute, and attack duration. The photocell proved more reliable than the microswitch and correlated highly with observations of both the number of interfood intervals with an attack for three subjects and attack duration for two. Neither apparatus provided accurate information about the rate of attacks. The microswitch apparatus was not sensitive to changes in the subject’s attack topography, while both recording devices were susceptible to activation by responses in the attacking pigeon other than discrete pecks or physical blows. In view of these findings, attacks per minute may not be an appropriate measure of aggression in studies using such devices.     

Relationships between redundancy analysis,canonical correlation,and multivariate regression

This paper attempts to clarify the nature of redundancy analysis and its relationships to canonical correlation and multivariate multiple linear regression. Stewart and Love introduced redundancy analysis to provide non-symmetric measures of the dependence of one set of variables on the other, as channeled through the canonical variates. Van den Wollenberg derived sets of variates which directly maximize the between set redundancy. Multivariate multiple linear regression on component scores (such as principal components) is considered. The problem is extended to include an orthogonal rotation of the components. The solution is shown to be identical to van den Wollenberg's maximum redundancy solution.This research was supported in part by U.S. Environmental Protection Agency contract 68-02-3402. The author gratefully acknowledges the stimulation of Maurice Tatsuoka and Beth Dawson-Saunders in first interesting him in redundancy analysis, as well as a useful change suggested by Warren Sarle.     

Amnestic effect of intrahippocampal AM251, a CB1-selective blocker, in the inhibitory avoidance, but not in the open field habituation task, in rats

CB1 is the most abundant metabotropic receptor of the brain, being found in areas classically involved in learning and memory and present at higher density at presynaptic terminals. Different sets of evidence support the idea that endogenous ligands (endocannabinoids) to the CB1 receptors act as modulators of neurotransmission. In hippocampus, endocannabinoids seem to act as retrograde messengers mediating down-regulation of GABA release. Previous reports have described a cognitive impairment effect of cannabinoid agonists, or facilitation by antagonists. The scope of the present study is to investigate the effect of intrahippocampal administration of the CB1-selective antagonist, AM251, in two behavioral tasks. One hundred and twelve male Wistar rats with bilateral cannulae implanted in the CA1 region of the dorsal hippocampus were trained in a step-down inhibitory avoidance task (IA, footshock, 0.5 mA) or an open field habituation task (OF). Immediately, after training, animals received an infusion of 0.55, 5.5, and 55.5 ng/side of AM251 (Tocris), or its vehicle (DMSO/saline), via these cannulae. Our results show that AM251 disrupted memory consolidation of the IA task, but not the OF task, an effect that seems to be purely mnemonic since the drug showed no motor performance effects. Only the intermediate dose (5.5 ng/side) of AM251 was effective in IA and the absence of effect with the larger dose may be the consequence of non-specific binding. The fact that OF was not affected raises the possibility that this endogenous system requires some degree of aversiveness to be recruited. We propose that increased levels of endogenous cannabinoids in the hippocampus, following a training session, contribute to facilitate memory consolidation, a process that may have been disrupted with AM251.     

Circular Discernment in Completely Extensive Structures and How to Avoid such Circles Generally

In this journal, D. Rizza [11] (p. 176) expounded a solution of what he called ??the indiscernibility problem for ante rem structuralism??, which is the problem to make sense of the presence, in structures, of objects that are indiscernible yet distinct, by only appealing to what that structure provides. We argue that Rizza??s solution is circular and expound a different solution that not only solves the problem for completely extensive structures, treated by Rizza, but for nearly (but not) all mathematical structures.     

Time-dependent effects of treadmill exercise on aversive memory and cyclooxygenase pathway function

Exercise induces brain function adaptations and improves learning and memory; however the time window of exercise effects has been poorly investigated. Studies demonstrate an important role for cyclooxygenase-2 (COX-2) pathway function in the mechanisms underlying memory formation. The aim of present work was to investigate the effects of treadmill exercise on aversive memory and COX-2, PGE(2) and E-prostanoid receptors contents in the rat hippocampus at different time points after exercise has ended. Adult male Wistar rats were assigned to non-exercised (sedentary) and exercised (running daily for 20min, for 2weeks) groups. The inhibitory avoidance task was used to assess aversive memory and the COX-2, PGE(2) and E-prostanoid receptors (EP1, EP2, EP3 and EP4) levels were determined 1h, 18h, 3days or 7days after the last training session of treadmill exercise. The step down latency in the inhibitory avoidance, COX-2 and EP4 receptors levels were acutely increased by exercise, with a significant positive correlation between aversive memory performance and COX-2 levels. Increased EP2 content decreased PGE(2) levels were observed 7days after the last running session. The treadmill exercise protocol facilitates inhibitory avoidance memory and induces time-dependent changes on COX-2 pathways function (COX-2, PGE(2) and EP receptors).     

Is memory for remembering? Recollection as a form of episodic hypothetical thinking

Misremembering is a systematic and ordinary occurrence in our daily lives. Since it is commonly assumed that the function of memory is to remember the past, misremembering is typically thought to happen because our memory system malfunctions. In this paper I argue that not all cases of misremembering are due to failures in our memory system. In particular, I argue that many ordinary cases of misremembering should not be seen as instances of memory’s malfunction, but rather as the normal result of a larger cognitive system that performs a different function, and for which remembering is just one operation. Building upon extant psychological and neuroscientific evidence, I offer a picture of memory as an integral part of a larger system that supports not only thinking of what was the case and what potentially could be the case, but also what could have been the case. More precisely, I claim that remembering is a particular operation of a cognitive system that permits the flexible recombination of different components of encoded traces into representations of possible past events that might or might not have occurred, in the service of constructing mental simulations of possible future events. So that imagination and memory are but one thing, which for diverse considerations hath diverse names. Thomas Hobbes, Leviathan 1.2.      

On Being Exposed to Superior Others: Consequences of Self-Threatening Upward Social Comparisons

Being inferior to someone else can be hurtful. But what exactly happens when we found ourselves in such situations? We first address why and when upward comparison can be self-threatening and later review the effects of such threatening social comparison. We argue that two main kinds of disturbances can ensue: affective disturbances and attentional disturbances. Second, three ways to deal with self-threatening social comparison are reviewed: proactive regulation, defensive regulation, and regulation by avoidance. For each of these disturbances and regulation modes, we review empirical findings and later discuss the impact of upward comparison on performance. We conclude by going back to the very need behind the need for a positive evaluation.     

LATINAS WITHOUT WORK

This study examines stressors in family, occupational, and economic domains among 114 Latinas following job loss. These women had been displaced from their jobs for at least 18 months at the time of the initial survey. Stressors from the occupational stress domain were the greatest source of stress for these women. Despite the passage of over 18 months since job loss, 75% of these women remained unemployed. Women who valued the job they lost and who were older reported the highest level of occupational stress. In the economic stress domain, Latinas with greater involvement in the mainstream U.S. economy and its obligations, who also had less seniority, and less disposable income, reported the greatest levels of stress. An imbalance between demands imposed by financial obligations and inadequate financial resources appeared to be a major factor in the stress levels experienced in the economic stress domain. Although the present study is limited by a small sample size, the findings challenge the myth of benign stress associated with female unemployment in general, and with Latina unemployment in particular.