Electrolytic lesions of the pedunculopontine nucleus disrupt concurrent learned aversion induced by NaCl

Bilateral electrolytic lesions in the pedunculopontine nucleus (PPN) impair acquisition of short-term, or concurrent, Taste Aversion Learning (TAL) in rats. This type of TAL is characterized by the daily presentation of two different flavor stimuli at the same time, one associated with simultaneous intragastric administration of an aversive product (hypertonic NaCl) and the other with physiological saline. Sham-lesioned control animals learn this taste discrimination task, but both lesioned animals and control animals learn a long-term, or delayed, TAL task in which each gustatory stimulus is presented individually every other day and the intragastric products, LiCl (0.15 M) and physiological saline, are administered after a 15-min delay. These results are analyzed in the context of the cerebellar circuits involved in learning and in relation to the two TAL modalities described above.     

Minimal experience required for immediate-early gene induction in zebra finch neostriatum

We show that a single presentation of a zebra finch song, 2 s in duration, will induce an "immediate-early gene" response in the caudomedial neostriatum of zebra finches (Poephila guttata). Repetition of this stimulus 10 times is sufficient to induce a maximal increase in RNA and protein, detected 30 and 90 min later respectively. Thus very brief stimuli can set in motion a slow genomic process in the brain which takes hours to resolve. Immediate-early gene function is often considered in the context of a "feedback" model (i.e., to consolidate memories of the inducing event). However, based on the long lag observed here between initiation and full expression of the molecular response, we suggest an alternative, ethologically based, "feed-forward" model in which exposure to a novel or significant context triggers an increase in the efficiency of memory capture processes for subsequent experiences.     

Measurement and structural models for children's problem behaviors

This article considers an analytic strategy for measuring and modeling child and adolescent problem behaviors. The strategy embeds an item response model within a hierarchical model to define an interval scale for the outcomes, to assess dimensionality, and to study how individual and contextual factors relate to multiple dimensions of problem behaviors. To illustrate, the authors analyze data from the primary caregiver ratings of 2,177 children aged 9-15 in 79 urban neighborhoods on externalizing behavior problems using the Child Behavior Checklist 4-18 (T. M. Achenbach, 1991a). Two subscales, Aggression and Delinquency, are highly correlated, and yet unidimensionality must be rejected because these subscales have different associations with key theoretically related covariates.     

Dyskinesias differentiate autistic disorder from catatonia

Autistic disorder and catatonia are neuropsychiatric syndromes defined by impairments in social interaction, communication, and restricted, stereotypical motor routines. Assessments of children with these disorders are typically restricted in scope by the patients' limited ability to comprehend directions. The authors performed systematic assessments of dyskinesias on six prepubertal boys with autistic disorder and mental retardation and on one adolescent male with catatonia to determine if this type of information could be routinely obtained. The boys with autistic disorder had more stereotypies and tics, a greater degree of akathisia and hyperactivity, and more compulsions than the adolescent with catatonia. Catatonia was associated with catalepsy and dystonic postures. The authors conclude that the diagnostic accuracy and specificity of neuropsychiatric syndromes may be enhanced by the systematic assessment of the dyskinesias associated with each condition.     

Psychology in the human sciences in France, 1920-1940: Ignace Meyerson's historical psychology

Between World War I and World War II, psychology adopted a direction open to human sciences; I. Meyerson was the main organizer of this choice. Leading the Societe de Psychologie and the Journal de Psychologie Normale et Pathologique, he tried to construct an individual and collective psychology that reflected not only the scientific preoccupations of his masters and friends but also their political choices: They had been the founders of the Human Rights League at the end of the 19th century. Behind Durkheim and Seignobos, with Mauss, Levy-Bruhl, and Blondel, Meyerson answered the new historians' call for a unified science of "mentalities," a historical psychology of collective representations. Meyerson offered to sociologists, anthropologists, linguists, and historians several forums to debate in which psychology was the unifying science. But at the end of the World War II, his psychology was marginalized, and a postivistic and behavioristic way was preferred. Meyerson's historical psychology disappeared from academic psychology, but historians have preserved its legacy.     

Implicit and explicit learning of event sequences: evidence for distinct coding of perceptual and motor representations

Event-related brain potentials (ERPs) of 21 subjects were recorded in a choice reaction time task with a repeating eight-element long stimulus sequence. The regular event sequence was sometimes interrupted by 'perceptual' or by 'motor deviants' which both replaced an expected stimulus but either preserved or violated the sequence of motor responses. Response times confirmed that all subjects had acquired some knowledge of the sequential dependencies. By means of a post-experimental free recall and recognition test, subjects were classified as having either explicit or implicit knowledge of the event sequence. The ERPs showed different effects for different types of stimuli and the two groups. In the group of explicit learners, a larger N200 component was evoked by both types of deviants and a larger P300 by motor deviants only. In the group of implicit learners these 'perceptual components' remained unaffected. In contrast, in both groups of subjects the lateralized readiness potential (LRP) which accompanied motor deviants revealed a partial activation of the to be expected but incorrect response, i.e. motor learning. These results suggest that explicit learners acquire knowledge about both, stimulus and response dependencies while implicit learners acquire knowledge about response dependencies only.     

Individual development in a bio-cultural perspective

Biological and cultural inheritance deeply influence daily human behavior. However, individuals actively interact with bio-cultural information. Throughout their lives, they preferentially cultivate a limited subset of activities, values, and personal interests. This process, defined as psychological selection, is strictly related to the quality of subjective experience. Specifically, cross-cultural studies have highlighted the central role played by optimal experience or flow, the most positive and complex daily experience reported by the participants. It is characterized by high involvement, deep concentration, intrinsic motivation, and the perception of high challenges matched by adequate personal skills. The associated activities represent the basic units of psychological selection. Flow can therefore influence the selective transmission of bio-cultural information and the process of bio-cultural evolution.     

Illusory inferences from a disjunction of conditionals: a new mental models account

(Johnson-Laird, P.N., & Savary, F. (1999, Illusory inferences: a novel class of erroneous deductions. Cognition, 71, 191-229.) have recently presented a mental models account, based on the so-called principle of truth, for the occurrence of inferences that are compelling but invalid. This article presents an alternative account of the illusory inferences resulting from a disjunction of conditionals. In accordance with our modified theory of mental models of the conditional, we show that the way individuals represent conditionals leads them to misinterpret the locus of the disjunction and prevents them from drawing conclusions from a false conditional, thus accounting for the compelling character of the illusory inference.