Ivan Petrovich Pavlov and Santiago Ramón y Cajal, scientists and Nobel laureates of a new century / Iván Petrovich Pavlov y Santiago Ramón y Cajal, científicos y premios Nobel de un nuevo siglo

ABSTRACT Pavlov and Cajal were two influential scientists who developed their work in the late nineteenth and early twentieth centuries. Both won the Nobel Prize in Physiology or Medicine. The authors analyze the similarities between their life and work, delving into a single aspect: the Nobel prize obtained by both with only two years of difference: Pavlov in 1904 and Cajal in 1906, shared with Camilo Golgi. Both belonged to two declining empires when nationalism was still of some importance. The theories proposed by them more than 115 years ago are still valid in much of what they contributed in their respective disciplines.

RESUMEN Pavlov y Cajal fueron dos científicos influyentes que desarrollaron su trabajo a finales del siglo XIX y principios del XX. Ambos ganaron el premio Nobel de Fisiología o Medicina. Los autores analizan las similitudes entre su vida y obra, profundizando en un solo aspecto: el premio Nobel obtenido por ambos con tan solo dos años de diferencia: Pavlov en 1904 y Cajal en 1906, compartido con Camilo Golgi. Ambos pertenecían a dos imperios en decadencia, en un momento en que el nacionalismo todavía tenía cierta importancia. Las teorías propuestas por ellos, hace más de 115 años, siguen vigentes en lo fundamental de lo que aportaron en sus respectivas disciplinas.

La risa contagiosa como estímulo incondicionado en condicionamiento clásico de actitudes hacia marcas comerciales / Contagious Laughter as an Unconditioned Stimulus in Classical Conditioning of Attitudes Towards Commercial Brands

Resumen La literatura sobre condicionamiento clásico de actitudes (CCA) no reporta utilización de vocalizaciones humanas para crear o intensificar actitudes. El propósito del estudio fue comprobar la capacidad de los estímulos acústicos de risa contagiosa para originar actitudes positivas hacia marcas comerciales neutras cuando estos se utilizan como estímulos incondicionados en CCA. Participaron 60 universitarios de ambos sexos con edades entre 18 y 30 años y con base en un diseño experimental intrasujeto se aplicó el CCA, que implicó apareamiento simultáneo de marcas comerciales neutras con risas más y menos contagiosas. Se verificaron 5 hipótesis que compararon actitudes explícitas (medidas con diferencial semántico) e implícitas (medidas mediante un priming evaluativo y amplitud electromiográfica —EMC— del músculo cigomático) entre el pre- y el poscondicionamiento y entre marcas condicionadas con risas más vs. menos contagiosas. .on respecto a línea de base, se observaron mayores actitudes explícitas poscondicionamiento hacia marcas comerciales apareadas con risas más contagiosas; no se encontraron diferencias actitudinales explícitas entre marcas condicionadas con risas más vs. menos contagiosas. Sólo se evidenciaron diferencias actitudinales implícitas entre el pre y el poscondicionamiento de la marca comercial apareada con risa masculina más contagiosa. No se observaron diferencias en la amplitud EMG del cigomático entre el pre y el poscondicionamiento ni entre marcas comerciales apareadas con risas más vs. menos contagiosas. Concluimos que la risa contagiosa tiene capacidad para transferir valencia afectiva a estímulos neutros y no siempre se observa concordancia entre las actitudes explícitas e implícitas poscondicionamiento.

Abstract The literature on classical conditioning of attitudes (CCA) does not report the use of human vocalizations to create or intensify attitudes. This study aimed to test the ability of contagious laughter acoustic stimuli to elicit positive attitudes towards neutral commercial brands when used as unconditioned stimuli in CCA. 60 university students of both genders, aged between 18 and 30 years, participated. Based on an intra-subject experimental design the CCA was applied, which involved the simultaneous pairing of neutral commercial brands with more and less contagious laugher. Five hypotheses were tested comparing explicit (measured with semantic differential) and implicit attitudes (measured by evaluative priming and electromyographic amplitude -EMG- of the zygomatic muscle) between pre- and postconditioning and between commercial brands conditioned with more vs less contagious laugher. Concerning the baseline, there were greater explicit postconditioning attitudes towards commercial brands paired with more contagious laughter; no explicit attitudinal differences were found between brands conditioned with more vs. less contagious laughter. Only implicit attitudinal differences were evidenced between pre- and postconditioning for the commercial brand paired with the most contagious male laughter. No differences in the zygomatic EMG amplitude were observed between pre- and postconditioning or between commercial brands paired with more vs. less contagious laughter. We conclude that contagious laughter has the capacity to transfer affective valence to neutral stimuli and that concordance is not always observed between explicit and implicit postconditioning attitudes.

Efectos de una simetría facial alta, media y baja en un condicionamiento clásico de actitudes hacia logos / Effects of high, medium and low facial symmetry in a classical conditioning of attitudes of logos

Con 34 estudiantes de la Universidad de Ibagué (17 de cada sexo y una media de 21 años), se evaluó el efecto de la simetría facial (SF) en un Condicionamiento Clásico de Actitudes, mediante un procedimiento simultáneo donde los estímulos incondicionados fueron rostros femeninos con baja, media y alta SF, y como estímulos a condicionar tres logos (Xua, Xue y Xuo). Los resultados muestran una mejor evaluación de los rostros con alta SF; un cambio entre las evaluaciones realizadas antes y después a los logos y, finalmente, que la marca asociada a alta SF obtuvo una evaluación más positiva. Se valora el impacto del estudio en la operacionalización del atractivo físico, la identificación de estímulos incondicionados y las ventajas del procedimiento en la evaluación de comunicaciones persuasivas.

In a sample of 34 university students (17 of each sex and on average 21 years old) at the Universidad de Ibagué, we evaluated the effect of facial symmetry (FS) in a Classical Conditioning of Attitudes experiment, using a simultaneous procedure where three logos were used as conditioned stimuli (Xua, Xue, Xuo) and faces of varying symmetry were used as unconditioned stimuli. We observed a higher rating of attractiveness of faces with high FS. We also observed a change in ratings of each logo before and after the conditioning procedure, and finally, the logo associated with a high FS obtained significantly higher scores after conditioning (than the logos associated with less FS). The impact of our study is that we operationalized physical attractiveness, identifying an unconditioned stimulus (facial symmetry as an index of physical attractiveness) and demonstrated the advantage of our conditioning procedure in establishing and changing the attitudes of consumers in persuasive communications.

Memória Aversiva em Mamíferos e Aves: Relação entre o Hipocampo e o Condicionamento Clássico Aversivo / Aversive Memory in Mammals and Birds: Relationship between the Hippocampus and the Aversive Classical Conditioning

A análise dos comportamentos relacionados com o medo condicionado é um elemento central na maioria dos estudos de condicionamento clássico aversivo, possibilitando, assim, o estudo dos processos de aprendizagem e memória aversiva. Alguns trabalhos destacam um papel funcional importante do hipocampo na aquisição da resposta condicionada em situações de condicionamento de medo. A situação de aprendizagem de condicionamento clássico aversivo é avaliada pelo comportamento de congelamento, tanto ao som como ao contexto do condicionamento, também é avaliada pela magnitude das respostas ao som condicionado a um estímulo aversivo. Estudos sobre condicionamento clássico aversivo geralmente são referidos como condicionamento do medo, baseado no fato de que o comportamento de congelamento faz parte do repertório de defesa de roedores e outros animais. O condicionamento ao contexto está relacionado a estruturas cerebrais que não estão necessariamente envolvidas no condicionamento entre um estímulo discreto inócuo e um estímulo aversivo, por exemplo, o condicionamento som-choque. O objetivo deste estudo foi analisar o papel do hipocampo no condicionamento clássico aversivo. Quanto ao método, tratou-se de um trabalho de revisão sistemática de literatura. Foram utilizados livros e artigos publicados na base de dados Pubmed, Science Direct e SciELO nas línguas inglesa e portuguesa. Como resultados foram selecionados 38 trabalhos. Conclui-se que os trabalhos analisados confirmam o importante papel do hipocampo durante a aquisição e a recuperação da memória aversiva. Além disso, o material aqui apresentado pode ser utilizado para estimular pesquisas futuras sobre o tema, aspecto fundamental para a evolução do conhecimento.

The analysis of behaviors related to the conditioned fear is a central element in most studies of aversive classical conditioning, thus allowing the study of the processes of learning and aversive memory. Some studies highlight an important functional role of the hippocampus in the acquisition of the conditioned response in situations of conditioned fear. The learning situation of aversive classical conditioning is assessed by freezing behavior, concerning to the sound as well as to the context of the conditioning, and it is also evaluated by the magnitude of the response to the sound conditioned to an aversive stimulus. Studies on aversive classical conditioning are generally referred as fear conditioning based on the fact that the freezing behavior is part of the defense repertoire of rodents and other animals. The conditioning context is associated with brain structures that are not necessarily involved in the conditioning of a discrete an innocuous stimulus and an aversive stimulus, for example, sound-conditioning shock. The objective of this paper is to analyze the role of the hippocampus on aversive classical conditioning. The method used was a systematic review of the literature. Books and articles published in Pubmed, Science Direct and SciELO data in English and Portuguese languages were used. As a result, 38 papers were selected. We conclude that several studies have confirmed the important role of the hippocampus during acquisition and retrieval of aversive memory. In addition, the material presented here can be used to stimulate future research on the topic, fundamental point for the evolution of knowledge.

Cuando la contigüidad no es suficiente: bloqueo en relaciones de equivalencia / When Contiguity is not Enough: Blocking Equivalence Relations

El fenómeno de bloqueo describe una circunstancia en la cual se impide o se dificulta el la transferencia de funciones entre eventos que se han presentado en una relación de contigüidad espacio-temporal. Desde una perspectiva teórica y empírica, el efecto bloqueo no debería predecirse en la adquisición de clases de estímulos aun cuando algunos de los estímulos de la misma clase se presenten simultáneamente. El presente estudio examina si la historia adicional de entrenamiento A-EI bien sea previa o posterior al entrenamiento con un estímulo muestra compuesto AX, es la variable crítica en la presentación del efecto bloqueo. Los desempeños obtenidos en las pruebas de bloqueo por los participantes de un grupo expuesto al procedimiento de bloqueo, un grupo expuesto al procedimiento de bloqueo invertido, y un grupo control, sugieren que el entrenamiento adicional con un solo elemento del compuesto no impide la inclusión de todos los estímulos dentro de la clase. Los casos en los que se observó el efecto bloqueo se interpretan en términos de tipos de percepciones elementales y configurales.

The blocking effect describes a circumstance which impedes function transfer among events that are part of a relation of spatiotemporal contiguity. However, theoretical and empirical evidence in stimulus class acquisition predicts that the blocking effect should not be observed even if some of the stimul11n the class are presented simultaneously as compound stimuli. The present study examines if additional A-EI training, whether prior or following training with a compound sample AX, constitutes a critical variable in the occurrence of the blocking effect. Performances in blocking tests by a group exposed to the blocking procedure, a group exposed to the backward blocking procedure and a control group were compared. Findings suggest that additional training with one member of the compound does not impede responding to all stimuli as members of the class. Instances where the blocking effect was observed are interpreted in terms of configural and elemental types of responding.

Ivan Petrovich Pavlov

Ivan Pavlov was a renowned physiologist, psychologist and physician from Russia. His experimentation on digestive system of dogs and his observation of involuntary reflexes had made him a Nobel laureate. He is known for his research in classical conditioning and behavioural modification.

Evaluación del efecto de bloqueo en el condicionamiento clásico de preferencias / Assessment of the blocking effect in classical conditioning of preferences

Esta investigación experimental tuvo como objetivo poner a prueba el efecto de bloqueo de Kamin en el condicionamiento clásico de preferencias. Se diseñaron tres partes: Estudio 1, Experimento 1 y Experimento 2. El Estudio preliminar (n = 54) consistió en la elección de los estímulos condicionados (marcas publicitarias ficticias) y del estímulo incondicionado (figura femenina con una proporción controlada de la medida de cintura/ cadera). En el Experimento 1 (n = 60) se efectuó el entrenamiento en condicionamiento clásico de preferencias. Finalmente, en el Experimento 2 (n = 40), se examinó el efecto de bloqueo en el condicionamiento clásico de preferencias con pruebas de tipo cognoscitivo y afectivo. Participaron estudiantes universitarios de diferentes carreras entre 17 y 25 años. Los resultados indican que se manifestó un efecto de bloqueo en tres de las cuatro pruebas utilizadas para evaluar dicho fenómeno. Se plantea, a manera de conclusión, que este efecto potencialmente explica diferentes fenómenos en los campos de la publicidad y el mercadeo, especialmente en lo que concierne a competencia de marcas.

This experimental research was aimed to test Kamin's blocking effect in classical conditioning of preferences applied in the advertisement area. This study was divided into three parts: preliminary Study, Experiment 1, and Experiment 2. In the preliminary Study, both conditioned (a false publicity brand) and unconditioned stimuli (female figure with a controlled waist-to-hip ratio) were selected. Experiments 1 and 2 consisted of training in classical conditioning of preferences and blocking effect. 17-25 year-old undergraduate students of different careers participated in the present study. According to the results, a blocking effect was observed, suggesting an explanation for different phenomena in fields such as marketing or advertisement, especially when implying brands competition.

Learning processes and the neural analysis of conditioning

Classical and operant conditioning principles, such as the behavioral discrepancy-derived assumption that reinforcement always selects antecedent stimulus and response relations, have been studied at the neural level, mainly by observing the strengthening of neuronal responses or synaptic connections. A review of the literature on the neural basis of behavior provided extensive scientific data that indicate a synthesis between the two conditioning processes based mainly on stimulus control in learning tasks. The resulting analysis revealed the following aspects. Dopamine acts as a behavioral discrepancy signal in the midbrain pathway of positive reinforcement, leading toward the nucleus accumbens. Dopamine modulates both types of conditioning in the Aplysia mollusk and in mammals. In vivo and in vitro mollusk preparations show convergence of both types of conditioning in the same motor neuron. Frontal cortical neurons are involved in behavioral discrimination in reversal and extinction procedures, and these neurons preferentially deliver glutamate through conditioned stimulus or discriminative stimulus pathways. Discriminative neural responses can reliably precede operant movements and can also be common to stimuli that share complex symbolic relations. The present article discusses convergent and divergent points between conditioning paradigms at the neural level of analysis to advance our knowledge on reinforcement

Strain and sex differences in fear conditioning: 22 kHz ultrasonic vocalizations and freezing in rats

Strain and sex differences in fear conditioning were investigated in two commonly used laboratory rats: Sprague Dawleys and Long-Evans. Twenty-two kHz ultrasonic vocalization (USV) distress calls and freezing behavior were used to measure fear responses to contextual and auditory conditioned stimuli (CSs), which were previously paired with a footshock unconditioned stimulus (US). Both strain and sex had significant effects on USVs and freezing during training and subsequent context and tone tests. Overall, the male Sprague Dawley rats froze and emitted USVs more than the other groups. Additionally, levels of freezing and USVs were differentially influenced by the type of CS (context or tone). These results suggest that species-specific defense responses in laboratory rats are highly influenced by the strain and sex of the subject, and that these factors should be considered in future fear conditioning studies.

Condicionamiento clásico y cognición implícita / Classical conditioning and implicit cognition

En su conjunto, las evidencias experimentales conductuales y psicobiológicas revisadas en este artículo muestran que el condicionamiento clásico humano tiene una justificación evolutiva, se desarrolla mediante un procesamiento cognitivo diferente del procesamiento consciente y se sustenta en estructuras cerebrales diferentes. Dichas estructuras no suelen funcionar desligadas y por ello la combinación de ambas formas de procesamiento, explícito e implícito, es el patrón general en condiciones naturales. De hecho, debido a la organización jerárquica del sistema nervioso, suele existir un proceso de control de arriba hacia abajo (cortical-subcortical) pero, bajo condiciones especiales de laboratorio, puede hacerse evidente en la conducta, por ejemplo mediante los paradigmas de miedo condicionado, la estrecha relación entre procesamiento implícito y el condicionamiento clásico en nuestra especie.

Experimental data, behavioral and psychobiological, reviewed in this paper show that human classical conditioning has an evolutionary purpose, it is developed by means of a cognitive processing different from the conscious processing, and sustained by different cerebral structures. These structures usually do not work isolated. For that reason, combination of both forms of processing, explicit/implicit, is the general pattern in natural conditions. In fact, due to the hierarchical organization of the nervous system, usually it exists a top-down control process (cortical-subcortical) but, under special conditions of laboratory, can be behaviorally evident, for example by means of the fear conditioning, close relationship between implicit processing and Pavlovian conditioning in humans.