Limbic hypertension induced by stress and septal stimulation

For this study, it was postulated that hypertension of emotional origin is generated within the limbic system. To validate this thesis, septal induced blood pressure elevations were combined with a stressful experience in adult rats (spontaneously hypertensive and Wistar Kyoto rats). Stress consisted of intermittent confinement in a plexiglass tube. The results revealed that hypertension induced by electric stimulation of the septum during the stressful state could subsequently be elicited by the stressful state alone, without electric stimulation of the septum. It was postulated that the cortically modulated stress circuit converged with the electrically activated limbic pressor circuit at the level of the septum. This convergence resulted in the formation of one cortico-limbic circuitry which could be activated by stress alone. This underlying mechanism may be considered as a model of neural sensitization in the production of stress-induced limbic hypertension.     

Doing without representing?

Connectionism and classicism, it generally appears, have at least this much in common: both place some notion of internal representation at the heart of a scientific study of mind. In recent years, however, a much more radical view has gained increasing popularity. This view calls into question the commitment to internal representation itself. More strikingly still, this new wave of anti-representationalism is rooted not in armchair theorizing but in practical attempts to model and understand intelligent, adaptive behavior. In this paper we first present, and then critically assess, a variety of recent anti-representationalist treatments. We suggest that so far, at least, the sceptical rhetoric outpaces both evidence and argument. Some probable causes of this premature scepticism are isolated. Nonetheless, the anti-representationalist challenge is shown to be both important and progressive insofar as it forces us to see beyond the bare representational/non-representational dichotomy and to recognize instead a rich continuum of degrees and types of representationality.     

Long-term persistence of sort strategy in free classification

Two free classification experiments that investigate the persistence of sort strategy are reported. Participants tend to persist with their initial categorization type (family resemblance or unidimensional) for the remaining sorts, overriding the effects of otherwise influential stimulus properties. Sort type was found to persist even after a one-week delay. Stimulus-driven models of free classification (e.g., the SUSTAIN model, [Love, B. C., Medin, D. L., & Gureckis, T. M. (2004). SUSTAIN: A network model of category learning. Psychological Review, 111, 309-332]) cannot predict the sort type persistence effects we observe, but they are naturally accounted for by theories that posit strategic selection of a problem-solving strategy (e.g., Hypothesis theory, [Levine, M. (1971). Hypothesis theory and nonlearning despite ideal S-R-reinforcement contingencies. Psychological Review, 78, 130-140]).     

Temperament moderates the effect of the verbal threat information pathway on children's heart rate responses to novel animals

Temperamental variables such as trait anxiety are risk factors in children for the development of anxiety disorders. This experiment aimed to test whether temperament moderates the effect of verbal threat information on the physiological component of the fear emotion. An experiment is reported in which 6-10 year old children's (N = 54) fear beliefs about novel animals were measured. They were then given threat, positive or no verbal information about these animals following which their heart rate was recorded while they placed their hands in boxes that they believed these animals inhabited. Children also completed a questionnaire measure of trait anxiety. Child-reported temperament moderated the effect that threat information has on the physiological component of the fear emotion. Fear information is, therefore, a possible mechanism through which temperament leads children to acquire animal fears.     

Is Socrates free? The Theaetetus as case study

Most scholars agree that Plato’s concept of freedom, to the extent he has one, is ‘intellectualist’: true freedom is submission to the rule of reason through philosophical knowledge of rational order. Surprisingly, though, there are few explicit linkages of philosophy and freedom in Plato. Socrates is called many things in the dialogues, but not ‘free’. I aim to understand why by studying the Theaetetus, heretofore ignored in discussions of Platonic freedom. By examining the Digression (172c-177c) and Socrates’ ‘dream’ about wholes and parts (201c-206c), I show that describing freedom as ‘rule of reason’ simplifies what, for Plato, is a more tangled skein. In the Digression, philosophers are free in occupying a comprehensive standpoint transcending all limited and partial perspectives. Socrates’ dream, however, shows that logos cannot completely account for the knowledge of complex wholes or for itself as such a whole. Philosophical freedom cannot mean comprehensive discursive knowledge, then, since reason lacks a comprehensive grasp of itself. Socrates dreams of the rational whole, but is aware of why it remains only a dream, rather than wakeful knowledge. This awareness constitutes a freedom attained, not in total liberation from the confines of the partial human perspective, but within those confines.     

Brain Recording,Mind-Reading,and Neurotechnology: Ethical Issues from Consumer Devices to Brain-Based Speech Decoding

Science and Engineering Ethics - Brain reading technologies are rapidly being developed in a number of neuroscience fields. These technologies can record, process, and decode neural signals. This...     

Propagation of innovations in networked groups

A novel paradigm was developed to study the behavior of groups of networked people searching a problem space. The authors examined how different network structures affect the propagation of information in laboratory-created groups. Participants made numerical guesses and received scores that were also made available to their neighbors in the network. The networks were compared on speed of discovery and convergence on the optimal solution. One experiment showed that individuals within a group tend to converge on similar solutions even when there is an equally valid alternative solution. Two additional studies demonstrated that the optimal network structure depends on the problem space being explored, with networks that incorporate spatially based cliques having an advantage for problems that benefit from broad exploration, and networks with greater long-range connectivity having an advantage for problems requiring less exploration. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Memory for individuals: hamsters (Mesocricetus auratus) require contact to develop multicomponent representations (concepts) of others

In humans, individuals recognize other individuals by numerous types of independent information, such as the quality of the voice, appearance of the face, smell, gait, and posture. Humans also have integrated memories of others--that is, in response to a face or a voice the individual is recognized by name and other information about that individual is remembered. In many nonhuman species, individual recognition also occurs. Although observational studies suggest that individuals of some nonhuman species may be able to use several different cues for individual recognition, little experimental proof for this is available. Golden hamsters have at least 5 individually distinctive odors and they develop integrated, multi-odor memories (concepts) of familiar individuals, as shown by across-odor habituation experiments. Little is known, however, about the conditions that are necessary to develop such integrated memories. In these experiments we investigated what kinds of experiences were necessary for male hamsters to develop multiodor memories of females. The results show that exposure to all of the odors of another individual was not sufficient to develop such multiodor memories but that physical contact between the subjects and stimulus animals was necessary. Multiodor representations were developed after interactions with anesthetized individuals, confirming the finding that physical contact was important but also showing that interaction with an awake, behaving individual was not necessary to form multiodor representations of other individuals. We are not aware of experimental proof for integrated, multicomponant memories in any other nonhuman species.     

The verbal threat information pathway to fear in children: the longitudinal effects on fear cognitions and the immediate effects on avoidance behavior

Verbal information has long been assumed to be an indirect pathway to fear. Children (aged 6-8 or 12-13 years) were exposed to threat, positive, or no information about 3 novel animals to see the long-term impact on their fear cognitions and the immediate impact on avoidance behavior. Their directly (self-report) and indirectly (implicit association task) measured attitudes toward the animals changed congruent with the information provided, and the changes persisted up to 6 months later. Verbal threat information also induced behavioral avoidance of the animal. Younger children formed stronger animal- threat and animal-safe associations because of threat and positive verbal information than older children, but there were negligible age effects on self-reported fear beliefs and avoidance behaviors. These results support theories of fear acquisition that suppose that verbal information affects components of the fear emotion.