New Perspectives on beta-Adrenergic Mediation of Innate and Learned Fear Responses to Predator Odor

In the present study, we investigated the role of noradrenergic transmission in unconditioned and conditioned responses to predatory threats. First, we examined the effects of systemically injected beta-blockers on unconditioned and contextual conditioned response to cat odor. The centrally acting beta-blocker (propranolol) was able to impair unconditioned responses, as well as the acquisition of the contextual fear to cat odor; however, the peripherally acting (nadolol) was not effective. Next, we examined the neural substrate underlying the noradrenergic modulation of the defensive response to cat odor and focused on the dorsal premammillary nucleus (PMd), because it represents the hypothalamic site most responsive to predatory threats and, at the same time, presents a dense plexus of noradrenergic fibers. We were able to see that propranolol significantly reduced PMd-Fos expression in response to cat odor and that beta-adrenoceptor blockade in the PMd, before cat odor exposure, reduced defensive responses to the cat odor and to the cat odor-related environment. We have also shown that beta-adrenoceptor blockade in the PMd, before the exposure to cat odor-related context, impaired the contextual conditioned responses. Overall, the present results provide convincing evidence suggesting that central noradrenergic mediation is critical for the expression of unconditioned and contextual conditioned antipredatory responses. We have further shown that the PMd appears to be an important locus to mediate these beta-adrenoceptor effects.

Investigation of the hypothalamic defensive system in the mouse

The hypothalamus plays especially important roles in various endocrine, autonomic, and behavioral responses that guarantee the survival of both the individual and the species. In the rat, a distinct hypothalamic defensive circuit has been defined as critical for integrating predatory threats, raising an important question as to whether this concept could be applied to other prey species. To start addressing this matter, in the present study, we investigated, in another prey species (the mouse), the pattern of hypothalamic Fos immunoreactivity in response to exposure to a predator (a rat, using the Rat Exposure Test). During rat exposure, mice remained concealed in the home chamber for a longer period of time and increased freezing and risk assessment activity. We were able to show that the mouse and the rat present a similar pattern of hypothalamic activation in response to a predator. Of particular note, similar to what has been described for the rat, we observed in the mouse that predator exposure induces a striking activation in the elements of the medial hypothalamic defensive system, namely, the anterior hypothalamic nucleus, the dorsomedial part of the ventromedial hypothalamic nucleus and the dorsal premammillary nucleus. Moreover, as described for the rat, predator-exposed mice also presented increased Fos levels in the autonomic and parvicellular parts of the paraventricular hypothalamic nucleus, lateral preoptic area and subfornical region of the lateral hypothalamic area. In conclusion, the present data give further support to the concept that a specific hypothalamic defensive circuit should be preserved across different prey species. (C) 2008 Elsevier B.V. All rights reserved.

Sensing danger through the olfactory system: The role of the hypothalamic dorsal premammillary nucleus

The dorsal premammillary nucleus (PMd) has a critical role on the expression of defensive responses to predator odor. Anatomical evidence suggests that the PMd should also modulate memory processing through a projecting branch to the anterior thalamus. By using a pharmacological blockade of the PMd with the NMDA-receptor antagonist 2-amino-5-phosphonopentanoic acid (AP5), we were able to confirm its role in the expression of unconditioned defensive responses, and further revealed that the nucleus is also involved in influencing associative mechanisms linking predatory threats to the related context. We have also tested whether olfactory fear conditioning, using coffee odor as CS, would be useful to model predator odor. Similar to cat odor, shock-paired coffee odor produced robust defensive behavior during exposure to the odor and to the associated context. Shock-paired coffee odor also up-regulated Fos expression in the PMd, and, as with cat odor, we showed that this nucleus is involved in the conditioned defensive responses to the shock-paired coffee odor and the contextual responses to the associated environment. (C) 2008 Elsevier Ltd. All rights reserved.

Dissecting the brain`s fear system reveals the hypothalamus is critical for responding in subordinate conspecific intruders

Effective defense against natural threats in the environment is essential for the survival of individual animals. Thus, instinctive behavioral responses accompanied by fear have evolved to protect individuals from predators and from opponents of the same species (dominant conspecifics). While it has been suggested that all perceived environmental threats trigger the same set of innately determined defensive responses, we tested the alternate hypothesis that different stimuli may evoke differentiable behaviors supported by distinct neural circuitry. The results of behavioral, neuronal immediate early gene activation, lesion, and neuroanatomical experiments indicate that the hypothalamus is necessary for full expression of defensive behavioral responses in a subordinate conspecific, that lesions of the dorsal premammillary nucleus drastically reduce behavioral measures of fear in these animals, and that essentially separate hypothalamic circuitry supports defensive responses to a predator or a dominant conspecific. It is now clear that differentiable neural circuitry underlies defensive responses to fear conditioning associated with painful stimuli, predators, and dominant conspecifics and that the hypothalamus is an essential component of the circuitry for the latter two stimuli.

AMYGDALAR ROLES DURING EXPOSURE TO A LIVE PREDATOR AND TO A PREDATOR-ASSOCIATED CONTEXT

The amygdala plays a critical role in determining the emotional significance of sensory stimuli and the production of fear-related responses. Large amygdalar lesions have been shown to practically abolish innate defensiveness to a predator; however, it is not clear how the different amygdalar systems participate in the defensive response to a live predator. Our first aim was to provide a comprehensive analysis of the amygdalar activation pattern during exposure to a live cat and to a predator-associated context. Accordingly, exposure to a live predator up-regulated Fos expression in the medial amygdalar nucleus (MEA) and in the lateral and posterior basomedial nuclei, the former responding to predator-related pheromonal information and the latter two nuclei likely to integrate a wider array of predatory sensory information, ranging from olfactory to non-olfactory ones, such as visual and auditory sensory inputs. Next, we tested how the amygdalar nuclei most responsive to predator exposure (i.e. the medial, posterior basomedial and lateral amygdalar nuclei) and the central amygdalar nucleus (CEA) influence both unconditioned and contextual conditioned anti-predatory defensive behavior. Medial amygdalar nucleus lesions practically abolished defensive responses during cat exposure, whereas lesions of the posterior basomedial or lateral amygdalar nuclei reduced freezing and increased risk assessment displays (i.e. crouch sniff and stretch postures), a pattern of responses compatible with decreased defensiveness to predator stimuli. Moreover, the present findings suggest a role for the posterior basomedial and lateral amygdalar nuclei in the conditioning responses to a predator-related context. We have further shown that the CEA does not seem to be involved in either unconditioned or contextual conditioned anti-predatory responses. Overall, the present results help to clarify the amygdalar systems involved in processing predator-related sensory stimuli and how they influence the expression of unconditioned and contextual conditioned anti-predatory responses. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

The periaqueductal gray and its potential role in maternal behavior inhibition in response to predatory threats

Animals faced with conflicting cues, such as predatory threat and a given rewarding stimulus, must make rapid decisions to engage in defensive versus other appetitive behaviors. The brain mechanisms mediating such responses are poorly understood. However, the periaqueductal gray (PAG) seems particularly suitable for accomplishing this task. The PAG is thought to have, at least, two distinct general roles on the organization of motivated responses, i.e., one on the execution of defensive and reproductive behaviors, and the other on the motivational drive underlying adaptive responses. We have presently examined how the PAG would be involved in mediating the behavioral choice between mutually incompatible behaviors, such as reproduction or defense, when dams are exposed to pups and cat odor. First, we established the behavioral protocol and observed that lactating rats, simultaneously exposed to pups and cat odor, inhibited maternal behavior and expressed clear defensive responses. We have further revealed that cat odor exposure up-regulated Fos expression in the dorsal PAG, and that NMDA cytotoxic lesions therein were able to restore maternal responses, and, at the same time, block defensive responsiveness to cat odor. Potential paths mediating the dorsal PAG influences on the inhibition of appetitive (i.e., retrieving behavior) and consummatory (i.e., nursing) maternal responses are discussed. Overall, we were able to confirm the dual role of the PAG, where, in the present case, the dorsal PAG, apart from organizing defensive responses, also appears to account for the behavioral inhibition of non-defensive responses. (C) 2010 Elsevier B.V. All rights reserved.

Influência dos odores de gato e de cobra no comportamento defensivo e expressão de fos do sistema hipotalâmico de defesa de camundongo

Studies using neuronal tract-tracer in rat have shown that the anterior hypothalamic nucleus, dorsomedial division of the ventromedial nucleus of the hypothalamus and dorsal premammillary nucleus are highly connected. When the rat is exposed to predator or its odor these nuclei have shown a expression of Fos and their lesion reduces defensive behavior against predator. This set of nuclei was named the Hypothalamic Defense System. However, little is known about the response of this system to the odor of different predators or its role in mice. In this work, we exposed Swiss mice to two different predators odor (cat and snake) to verify the Fos expression in the Hypothalamic Defense System, as well as the defensive behaviors displayed. The analysis showed that the mice exposure to cat odor had an increased expression of Fos protein compared to control, while those exposed to snake odor showed no rise in Fos expression, which was corroborated by the behavioral data. Our results indicate that this distinct circuit in mice seems to act differentially to odorous stimuli of different predators, causing distinct behavioral responses of mice and that the odor of snake seems not to be perceived by Swiss mice as a threatening stimulus.

The little grey cat engine

The little grey cat engine (greyCat) is part of a series of projects which explore software which can enable access to the potentially empowering nature of represented space and game design. GreyCat is the result of research into the culture of the software itself in order to provide participatory environments which enable the telling of ‘small stories’ – stories and experiences which are those of the everyday or those of a cultural perspective other than that prioritised by most world building softwares or game engines. GreyCat offers a simple framework which allows participants to use their own image materials (photographs for the most part) as a basis for spatial exploration of their own places.---------- Truna aka j.turner (2008) The little grey cat engine: telling small stories (Demo), Australasian Computer Human Interaction Conference, OZCHI 2008, December 8th-12th, Cairns, Australia---------- Research Publications: truna aka j.turner & Browning, D. (2009) Designing spatial story telling software, in proceedings OZCHI09, Melbourne---------- Truna aka j.turner, Browning, D. & Champion, E. (2008) Designing for Engaged Experience, In proceedings Australasian Computer Human Interaction Conference, OZCHI 2008, December 8th-12th, Cairns, Australia---------- Truna aka. J.turner & Bidwell, N. (2007) Through the looking glass: game worlds as representations and views from elsewhere, Proceedings of the 4th Australasian conference on Interactive entertainment, Melbourne, Australia---------- Truna aka j.turner, Browning, D & Bidwell, N. (2007) Wanderer beyond game worlds, in proceedings, Hutchinson, A (ed) PerthDAC 2007: The seventh International Digital Arts and Culture Conference: The future of digital media culture, 15-18 September 2007, Perth, Australia, Curtin University of Technology---------- Truna aka j.turner (2006) To explore strange new worlds: experience design in 3 dimensional immersive environments - role and place in a world as object of interaction, In proceedings, Australasian Computer Human Interaction Conference, OZCHI 2006, November 22nd-24th, Sydney, Australia, November 20th – 24th 2006, pp 26- 29---------- Truna aka j.turner (2006) Digital songlines environment (Demonstration), In proceedings 2006 International conference on Game research and development, Perth, Australia---------- Truna aka j.turner (2006) Destination Space: Experiential Spatiality and Stories, Special Session on Experiential Spatiality, In proceedings 2006 International conference on Game research and development, Perth, Australia

CAT Detect (Computer Activity Timeline Detection) : a tool for detecting inconsistency in computer activity timelines

The construction of timelines of computer activity is a part of many digital investigations. These timelines of events are composed of traces of historical activity drawn from system logs and potentially from evidence of events found in the computer file system. A potential problem with the use of such information is that some of it may be inconsistent and contradictory thus compromising its value. This work introduces a software tool (CAT Detect) for the detection of inconsistency within timelines of computer activity. We examine the impact of deliberate tampering through experiments conducted with our prototype software tool. Based on the results of these experiments, we discuss techniques which can be employed to deal with such temporal inconsistencies.

Predicting psychologists’ intentions to integrate complementary and alternative therapies (CAT) into their practice.

This study assessed the validity of a scale measuring psychologists' attitudes towards complementary and alternative therapies and compared the attitudes of psychologists with a previous sample of psychology students. The scale, derived from existing measures for medical professionals and previously tested on a sample of psychology students, was completed by practising psychologists (N = 122). The data were factor analysed, and three correlated subscales were identified, assessing the perceived importance of knowledge about available therapies, attitudes towards integration with psychological practice, and concerns about associated risks of use. This structure was similar, but not identical, to that found in a previous sample of psychology students; however, psychologists expressed more concern for risks associated with integration and were less likely to hold a positive attitude towards integration. This scale will be useful in gauging changes in psychologists' attitudes towards integrative practice over time.

CAT-SLAM : probabilistic localisation and mapping using a continuous appearance-based trajectory

This paper describes a new system, dubbed Continuous Appearance-based Trajectory Simultaneous Localisation and Mapping (CAT-SLAM), which augments sequential appearance-based place recognition with local metric pose filtering to improve the frequency and reliability of appearance-based loop closure. As in other approaches to appearance-based mapping, loop closure is performed without calculating global feature geometry or performing 3D map construction. Loop-closure filtering uses a probabilistic distribution of possible loop closures along the robot’s previous trajectory, which is represented by a linked list of previously visited locations linked by odometric information. Sequential appearance-based place recognition and local metric pose filtering are evaluated simultaneously using a Rao–Blackwellised particle filter, which weights particles based on appearance matching over sequential frames and the similarity of robot motion along the trajectory. The particle filter explicitly models both the likelihood of revisiting previous locations and exploring new locations. A modified resampling scheme counters particle deprivation and allows loop-closure updates to be performed in constant time for a given environment. We compare the performance of CAT-SLAM with FAB-MAP (a state-of-the-art appearance-only SLAM algorithm) using multiple real-world datasets, demonstrating an increase in the number of correct loop closures detected by CAT-SLAM.

Evolution of the extinct Sabretooths and the American cheetah-like cat

The sabretooths (Smilodon and Homotherium) and the American cheetah-like cat (Miracinonyx) were the top predators in Late Pleistocene America, but became extinct about 13 thousand years ago. As the evolutionary history of these taxa remains poorly understood , we analysed their phylogenetic relationship to extant felids. In contrast to previous molecular studies , our results show that the sabretooths diverge early and are not closely related to any living cats. This supports their morphological placement in a separate subfamily (Machairodontinae). Despite its remarkable morphological similarity to the African cheetah (Acinonyx jubatus), Miracinonyx appears to have evolved from a puma-like ancestor, presumably in response to similar ecological pressures.

Capping computation time and storage requirements for appearance-based localization with CAT-SLAM

Appearance-based localization is increasingly used for loop closure detection in metric SLAM systems. Since it relies only upon the appearance-based similarity between images from two locations, it can perform loop closure regardless of accumulated metric error. However, the computation time and memory requirements of current appearance-based methods scale linearly not only with the size of the environment but also with the operation time of the platform. These properties impose severe restrictions on longterm autonomy for mobile robots, as loop closure performance will inevitably degrade with increased operation time. We present a set of improvements to the appearance-based SLAM algorithm CAT-SLAM to constrain computation scaling and memory usage with minimal degradation in performance over time. The appearance-based comparison stage is accelerated by exploiting properties of the particle observation update, and nodes in the continuous trajectory map are removed according to minimal information loss criteria. We demonstrate constant time and space loop closure detection in a large urban environment with recall performance exceeding FAB-MAP by a factor of 3 at 100% precision, and investigate the minimum computational and memory requirements for maintaining mapping performance.