Brain and behavior: on the perspective of Miguel Covian and César Timo-Iaria / Cérebro e comportamento: a perspectiva de Miguel Covian e César Timo-Iaria / Cerebro y comportamiento: la perspectiva de Miguel Covian y César Timo-Iaria

Historical studies of neuroscience in Brazil have focused on many aspects, including the relationship between brain and behavior. We present some notes on the concept of behavior, based on documents related to two Brazilian scientists identified as behavioral neuroscientists: Miguel Rolando Covian (1913-1992) and César Timo-Iaria (1925-2005). These neuroscientists used the concept of behavior in their debates about the connections between the nervous system and the environment. This use was influenced by physiological - especially neurophysiological - and experimental psychological studies. Describing and analyzing such documents and their authors, helps us to understand aspects of the history of neurosciences in Brazil during a period in which neuroscience was spreading rapidly in different countries.

Pesquisas em história das neurociências no Brasil têm focado diferentes aspectos, incluindo a relação entre cérebro e comportamento. Apresentamos notas sobre o conceito de comportamento, baseado em documentos de dois cientistas brasileiros identificados como neurocientistas comportamentais: Miguel Rolando Covian (1913-1992) e César Timo-Iaria (1925-2005). Esses neurocientistas utilizaram o conceito de comportamento em seus trabalhos sobre as conexões entre o sistema nervoso e o ambiente. Tal uso tinha influências da fisiologia - especialmente da neurofisiologia - e de estudos em Psicologia Experimental. A descrição de tais documentos e de seus autores nos auxiliam a compreender aspectos da história das neurociências no Brasil em um momento em que as neurociências se espalhavam fortemente ao redor do mundo.

Las investigaciones en la historia de las neurociencias en Brasil se han centrado en diferentes aspectos, incluida la relación entre cerebro y comportamiento. Nosotros presentamos apuntes sobre el concepto de comportamiento, de conformidad con documentos de dos cientistas brasileños identificados como neurocientistas comportamentales: Miguel Rolando Covian (1913-1992) y César Timo-Iaria (1925-2005). Eses neurocientistas utilizaron el concepto de comportamiento en sus trabajos sobre las conexiones entre el sistema nervioso y el ambiente. Dicho uso tenía influencias de la fisiología - especialmente de la neurofisiología - y de estudios en Psicología Experimental. Las descripciones de tales documentos y de sus autores nos ayudan a comprender aspectos de la historia de las neurociencias en Brasil en un momento en que las neurociencias se extendían fuertemente alrededor del mundo.

Cannabinoid system of dorsomedial telencephalon modulates behavioral responses to noxious stimulation in the fish Leporinus macrocephalus.

Fish dorsomedial telencephalon has been considered a pallial region homologous to mammals amygdala, being considered a possible substrate for nociception modulation in this animal group. The present study aimed to evaluate the participation of the cannabinoid system of Dm telencephalon on nociception modulation in the fish Leporinus macrocephalus. We demonstrated that cannabidiol microinjection in Dm telecephalon inhibits the behavioral nociceptive response to the subcutaneous injection of 3% formaldehyde, and this antinociception is blocked by previous treatment with AM251 microinjection. Furthermore, AM251 microinjection in Dm prior to restraint stress also blockades the stress-induced antinociception. These results reinforce the hypothesis that this pallial telencephalic structure has a pivotal role in nociception modulation in fish.

GABAA-benzodiazepine receptors in the dorsomedial (Dm) telencephalon modulate restraint-induced antinociception in the fish Leporinus macrocephalus.

The possibility that fish experience pain has been denied based on the absence of the neural substrates to support this "experience". In this context, the identification of brain regions involved in nociception modulation could provide important insights regarding the processing of nociceptive information in fish. Our study evaluated the participation of the GABAA-benzodiazepine receptor in the dorsomedial (Dm) telencephalon in restraint-induced antinociception in the fish Leporinus macrocephalus through the microinjection of the anxiolytic drug midazolam. The microinjection of midazolam in the Dm did not alter the nocifensive response; however, this drug did block the inhibition of the nocifensive response to formaldehyde promoted by restraint stress. The fish that received midazolam (40nmol) microinjection prior to restraint (3 or 5min), followed by subcutaneous injection with formaldehyde presented a higher distance traveled than the fish that received saline microinjection. This effect might reflect the specific action of midazolam on benzodiazepine receptors in the Dm telencephalon, as pre-treatment with flumazenil, a benzodiazepine receptor antagonist, inhibited the effects of this drug. In the present study, we present the first evidence demonstrating a role for the dorsomedial telencephalic region in the modulation of stress-induced antinociception in fish, revealing new perspectives in the understanding of nociceptive information processing in this group.

Acute administration of a cannabinoid CB1 receptor antagonist impairs stress-induced antinociception in fish.

This study evaluated the influence of the pre-treatment with AM251 (a cannabinoid type I receptor (CB1) selective antagonist) on the stress-induced antinociception promoted by restraint in the fish Leporinus macrocephalus. The application of 3 and 5 min of restraint stress promoted an inhibition of the behavioural response to the subcutaneous injection of 3% formaldehyde (increase in locomotor activity), suggesting the activation of an antinociceptive system. The acute intraperitoneal administration of AM251 (3 mg·kg(-1)) impaired this antinociceptive response induced by 3 and 5 min of restraint stress. The fish treated with AM251 before the application of restraint stress presented an increase in locomotor activity after the subcutaneous injection of formaldehyde, similar to fish not exposed to restraint, suggesting that the stress-induced antinociception promoted by restraint in fish is probably mediated by cannabinoid CB1 receptors. The results presented in this paper suggest the participation of the endocannabinoid system in nociception modulation in fish, supporting the hypothesis that an endogenous antinociceptive system activated by restraint stress is present in fish and that the modulation of antinociception by the CB1 receptor is evolutionary well-conserved across vertebrates.

Cortisol influences the antipredator behavior induced by chemical alarm cues in the Frillfin goby.

We evaluated the effect of increased plasma cortisol levels on fish antipredator behavior induced by conspecific chemical alarm cues. The experimental model for the study was the Frillfin goby Bathygobius soporator. We first confirmed that the alarm substance induces typical defensive antipredator responses in Frillfin gobies and described their alarm substance cells (epidermal 'club' cells). Second, we confirmed that intraperitoneal cortisol implants increase plasma cortisol levels in this species. We then demonstrated that exogenous cortisol administration and subsequent exposure to an alarm substance decreased swimming activity to a greater extent than the activity prompted by either stimulus alone. In addition, cortisol did not abolish the sheltering response to the alarm chemical cue even though it decreased activity. As predators use prey movements to guide their first contact with the prey, a factor that decreases swimming activity clearly increases the probability of survival. Consequently, this observation indicates that cortisol helps improve the antipredator response in fish.

Stress-induced antinociception in fish reversed by naloxone.

Pain perception in non-mammalian vertebrates such as fish is a controversial issue. We demonstrate that, in the fish Leporinus macrocephalus, an imposed restraint can modulate the behavioral response to a noxious stimulus, specifically the subcutaneous injection of 3% formaldehyde. In the first experiment, formaldehyde was applied immediately after 3 or 5 min of the restraint. Inhibition of the increase in locomotor activity in response to formaldehyde was observed, which suggests a possible restraint-induced antinociception. In the second experiment, the noxious stimulus was applied 0, 5, 10 and 15 min after the restraint, and both 3 and 5 min of restraint promoted short-term antinociception of approximately 5 min. In experiments 3 and 4, an intraperitoneal injection of naloxone (30 mg.kg(-1)) was administered 30 min prior to the restraint. The 3- minute restraint-induced antinociception was blocked by pretreatment with naloxone, but the corresponding 5-minute response was not. One possible explanation for this result is that an opioid and a non-preferential µ-opioid and/or non-opioid mechanism participate in this response modulation. Furthermore, we observed that both the 3- and 5- minutes restraint were severely stressful events for the organism, promoting marked increases in serum cortisol levels. These data indicate that the response to a noxious stimulus can be modulated by an environmental stressor in fish, as is the case in mammals. To our knowledge, this study is the first evidence for the existence of an endogenous antinociceptive system that is activated by an acute standardized stress in fish. Additionally, it characterizes the antinociceptive response induced by stress in terms of its time course and the opioid mediation, providing information for understanding the evolution of nociception modulation.

Antinociception in piauçu fish induced by exposure to the conspecific alarm substance.

Defense and antinociceptive responses can be elicited simultaneously by learned or innate danger signals when an organism is in imminent danger. Antinociception blocks the recuperative behavioral reactions following pain perception that could interfere with defensive efforts. Antinociception associated with fearful experiences involving a confrontation with a predator or a predator being in close proximity is well studied in mammals, but very little is known about how fear affects antinociception responses in fish. Antipredator behavior in Ostariophysan fish may be elicited by exposure to conspecific alarm substance (CAS) that can trigger a fear reaction. During the predator versus prey confrontation, the alarm pheromone system is activated and warns conspecifics about the assessment of predation risk. The purpose of the present study was to examine the possible activation of the endogenous analgesic system in Leporinus macrocephalus fish and to evaluate the modification of swimming activity induced by a nociceptive stimulus (i.e., a subcutaneous injection of 3% formalin) in fish that had previously been exposed to the CAS. The results show that formalin-mediated enhancement in swimming activity was significantly reduced after exposure to the CAS. This enhancement was blocked by naloxone (20mg/kg), which suggests that opioid signaling is involved. Therefore, we hypothesized that antinociceptive processes may occur in fish following exposure to a chemical substance that signals predation.

Behavioral characterization of the alarm reaction and anxiolytic-like effect of acute treatment with fluoxetine in piauçu fish.

In Ostariophysan fish, the detection of the alarm substance liberated into the water as a consequence of an attack by a predator elicits an alarm reaction or anti-predatory behavior. In this study, experiments were performed to: (i) describe and quantitatively characterize the behavioral and ventilatory responses in piauçu fish (Leporinus macrocephalus), individually and as part of a school, to conspecific alarm substance (CAS) and; (ii) test the effect of acute fluoxetine treatment on alarm reaction. Histological analysis revealed the presence of club cells in the intermediate and superficial layers of the epidermis. The predominant behavioral response to CAS was freezing for fish held individually, characterized by the cessation of the swimming activity as the animal settles to a bottom corner of the aquarium. Fish exposed to CAS showed decrease in the mean ventilatory frequency (approximately 13%) relative to control. In schools, CAS elicited a biphasic response that was characterized by erratic movements followed by increased school cohesion and immobility, reflected as an increased school cohesion (65.5% vs. -5.8% for controls) and in the number of animals near the bottom of the aquarium (42.0% vs. 6.5% for controls). Animals treated with single i.p. injections of fluoxetine (10 µg/g b.w.) did not exhibit alarm behavior following CAS stimulation. These results show that an alarm pheromone system is present in piauçu fish, evidenced by the presence of epidermal club cells and an alarm reaction induced by CAS and consequently of a chemosensory system to transmit the appropriate information to neural structures responsible for initiating anti-predator behavioral responses. In addition, fluoxetine treatment caused an anxiolytic-like effect following CAS exposure. Thus, the alarm reaction in piauçu can be a useful model for neuroethological and pharmacological studies of anxiety-related states.

Glomerular nucleus of the weakly electric fish, Gymnotus sp.: cytoarchitecture, histochemistry, and fiber connections--inisights from neuroanatomy to evolution and behavior.

The present study provides a detailed description of morphological and hodological aspects of the glomerular nucleus in the weakly electric fish Gymnotus sp., and explores the evolutionary and functional implications flowing from this analysis. The glomerular nucleus of Gymnotus shows numerous morphological similarities with the glomerular nucleus of percomorph fish, although cytoarchitectonically simpler. In addition, congruence of the histochemical acetylcholinesterase (AChE) distribution with cytoarchitectonic data suggests that the glomerular nucleus, together with the ventromedial cell group of the medial subdivision of the preglomerular complex (PGm-vmc) rostrally, and the subglomerular nucleus (as identified by Maler et al. [1991] J Chem Neuroanat 4:1­38) caudally, may form a distinct longitudinally organized glomerular complex. Our results show that an important source of sensory afferents to the glomerular nucleus originates in the pretectal and electrosensorius nuclei. The glomerular nucleus in turn projects to the hypothalamus (inferior lobe and anterior hypothalamus), to the anterior tuberal nucleus, and to the medial region of the preglomerular nucleus (PGm). These data suggest that visual and electrosensory information reach the glomerular nucleus and are relayed to the hypothalamus and, via PGm, to the pallium. Such connections are similar to those of the glomerular nucleus in percomorphs and the posterior pretectal nucleus in osteoglossomorph, esocids, and salmonids, where they comprise one component of a visual processing pathway. In Gymnotiform fish, however, the pretectal region that projects to the glomerular nucleus is dominated by electrosensory input (visual input is minor), which is consistent with the dominant role of electroreception in these fish.

Avaliação dos cursos de extensão universitária realizados pela Faculdade de Medicina de Ribeirão Preto da USP entre 2002 e 2008 / Evaluation of the university extension courses promoted by the Medical School of Ribeirão Preto of the University of São Paulo between 2002 and 2008

Introdução: A RESOLUÇÃO da Comissão de Cultura e Extensão da Universidade de São Paulo- CoCEx-5072 da Universidade de São Paulo(USP) regulamentou os cursos de extensão universitária. A Faculdade de Medicina de Ribeirão Preto da USP(FMRP-USP) passou a incentivar que diversos cursos não regulamentados fossem oficializados. Diversos empecilhos foram detectados, sendo necessário reavaliar o processo. Metodologia: Foram avaliados 106 cursos de extensão universitária realizados entre 2002 e 2008. Obteve-se dados referentes ao tipo de curso, Departamento responsável, regularidade e número de vagas oferecidas, comparando-se com a situação dos cursos no Sistema Apolo-USP. O trâmite dos processos foi avaliado através da diferença em dias entre o início e o final do processo. Todos os cursos que tiveram os certificados emitidos e anexados ao processo foram classificados como concluídos. Resultados: 1) O número de cursos regulamentados realizados pela FMRP-USP é baixo, sendo muito inferior à sua potencialidade; 2) A maioria dos cursos compreende cursos de curta duração (Difusão) esão reproduzidos em caráter anual; 3) A Comissão de Cultura e Extensão da FMRP-USP não dispõe de pessoal suficiente para gerenciamento dos cursos, dificultando ações de orientação e tramitação de processos...

Background: University of São Paulo(USP) CoCEx-5072 resolution regulates university extension courses. The Medical School of Ribeirão Preto USP(MSRP-USP) has adhered and incentivates documentation of all courses conducted. Several problems were identified, being mandatory process reconducted between 2002 and 2008 were evaluated. Data regarding course type, duration, regularity and number of attendees were recovered and compared with the official USP Apolo web system. Duration of process was calculated through the difference between date of beggining and end of process. All courses were considered concluded when certification was emited. Results: 1)The number of courses conducted by MSRP-USP is low, much inferior to its potential; 2) Th majority of courses comprehends short duration courses (Difusion) conducted on a yearly basis; 3)There were problems with personal for guiding and documenting the courses in the MSRP-USP...

Fiber connections of the diencephalic nucleus tuberis anterior in the weakly electric fish, Gymnotus cf. carapo: an in vivo tract-tracing study.

Transport of biotinylated dextran amine shows the spatial segregation of mechanosensory afferents in the nucleus tuberis anterior (TA) of a gymnotiform fish, Gymnotus cf. carapo. Only the intermediate subdivision of this nucleus receives projections from the lateral region of the ventral torus semicircularis (TSv), which represents the principal midbrain center for mechanosensory information processing, and from the ventral nucleus praeeminentialis, which receives collaterals of ascending second order mechanosensory fibers that emerge from the mechanosensory lateral line lobe. Considering this aspect, a rostrocaudal subdivision of the TA is proposed. The TA also receives input from regions subserving other sensory modalities, suggesting a role in multisensory interaction. Another important finding of this work consisted in the demonstration of reciprocal connections between the TA and the inferior lobe of the hypothalamus, which is known to receive gustatory, visual, and electrosensory input and is therefore considered a multisensory integration center involved in feeding and aggressive behavior. Furthermore, reciprocal connections between the TA and the preelectromotor central-posterior/prepacemaker complex may provide an access for the processed mechanosensory information to interact with the transient modulations of the electric organ discharge that accompany different behaviors.

Potential output pathways for agonistic-like responses resulting from the GABA(A) blockade of the torus semicircularis dorsalis in weakly electric fish, Gymnotus carapo.

The purpose of this study is to examine the pathways involved in the electromotor (electric organ discharge interruptions) and skeletomotor responses (defense-like) observed by blockade of GABAergic control of the torus semicircularis dorsalis (TSd) of the awake weakly electric fish Gymnotus carapo, described in a former study. Microinjection of NMDA (5 mM) into the pacemaker nucleus (PM) through a guide cannula previously implanted caused a prolonged interruption of the electric organ discharge (EOD) intermingled with reduction in frequency, similar to that described for TSd GABA(A) blockade, but without noticeable skeletomotor effects. The EOD alterations elicited by bicuculline microinjections (0.245 mM) into the TSd could be blocked or attenuated by a previous microinjection of AP-5 (0.5 mM), an NMDA antagonist, into the PM. Labeled terminals are found in the nucleus electrosensorius (nE) after injection of the biotinylated dextran amine (BDA) tracer into the TSd and into the sublemniscal prepacemaker nucleus (SPPn) subsequent to the tracer injection into the nE. Defense-like responses but not EOD interruptions are observed after microinjections of NMDA (5 mM) into the rhombencephalic reticular formation (RF), where labeled terminals are seen after BDA injection into the TSd and somata are filled after injection of the tracer into the spinal cord. In this last structure, marked fibers are seen subsequent to injection of BDA into the RF. These results suggest that two distinct pathways originate from the torus: one for EOD control, reaching PM through nE and SPPn, and the other one for skeletomotor control reaching premotor reticular neurons. Both paths could be activated by toral GABA(A) blockade.

Effects of exercise on plasma catecholamine levels in the toad, Bufo paracnemis: role of the adrenals and neural control.

Resting plasma epinephrine (E) and norepinephrine (N) concentrations for intact toads (Bufo paracnemis) were 5.57+/-1.0 and 0.88+/-0.38 ng/ml, respectively. Exercise induced a significant increase in heart rate, blood pressure and plasma epinephrine (about 4.3 times), whereas norepinephrine remained unchanged. The resting [E]/[N] ratio was 6.3 and increased to 32.9 during exercise. Adrenal denervation did not alter the basal plasma catecholamine or norepinephrine levels after exercise, but prevented the increase in epinephrine during exercise, suggesting that in the intact toad this increase is due to adrenal secretion whereas resting norepinephrine may be liberated by extra-adrenal chromaffin tissues. This also suggests that the adrenal glands can release selectively the two catecholamines. The increases in heart rate and blood pressure in denervated toads were not significantly different from those of intact animals, suggesting that during exercise the sympathetic nerves play the main role in inducing cardiovascular responses. Spinal transection induced a significant increase in basal norepinephrine levels, which remained elevated after exercise. Since spinal toads are unable to perform spontaneous movements it is possible that this increase may be caused by this stressful condition. The increases in heart rate and blood pressure observed in spinal toads during exercise may be due to direct mechanical effects of venous return on the heart.

Stressful and behavioral conditions that affect reversible cardiac arrest in the Nile tilapia, Oreochromis niloticus (Teleostei).

The objective of the present investigation was to study the reversible cardiac arrest (RCA) to visual stimuli in the unrestrained Nile tilapia (Oreochromis niloticus) as well as the modulation of this response and its behavioral component (arousal/orientation or startle response) by external and internal factors that interfere with alertness and emotionality. The study was preceded by the determination of the autonomic receptors that contribute to the establishment of the heart rate (HR) and the RCA. Systemic injection of atropine and propranolol showed that a double cardiac autonomic control is present in the tilapia. Basal HR was 79.8+/-1.8 beats min(-1) and HR assessed after double autonomic blockade was 74.1+/-3.3 beats min(-1). The mean interbeat interval was 0.79+/-0.40 s during baseline recording and the magnitude of RCA induced by a moving shadow (2.67+/-0.22 s) was higher than that induced by light (1.53+/-1.11 s). RCA is peripherally mediated by muscarinic receptors for it is abolished by atropine but not by propranolol. Stressful conditions like handling the animal outside the water or a nociceptive stimulus (subcutaneous 2% or 3% formalin injection) reduced the cardiac interbeat interval. A subanesthetic dose of barbiturate (5 mg kg(-1)) inhibited RCA induced by a moving shadow stimulus and the startle response, suggesting that an ideal degree of vigilance is necessary for its occurrence. Benzodiazepine injections (1.0 and 2.0 mg kg(-1)) abolished the reduction in magnitude of RCA induced by handling stress and facilitated the startle response, seen in the dry-cold season, in a dose-dependent manner. These data suggest that drugs that act on alertness and on emotionality modulate the magnitude of cardiac interbeat intervals and the corresponding behavioral response.

Claude Bernard e o método experimental / Claude Bernard and the experimental method

Este trabalho ressalta a influência do fisiologista francês Claude Bcrnard (l8l3-1878) na consagraçao do uso do método experimental na medicina. Analisa sua obra como pesquisador e como pensador do método experimental. O impacto de suas idéias no ambiente cultural e científico de sua época é avaliado, bem como sua remota influência na introduçao da fisiologia experimental no Brasil.