RESUMEN
BACKGROUND: The utilization of methylphenidate (MPH) is experiencing a notable surge within the adult population. This growth can be attributed to two key factors: its recreational and cognitive enhancement purposes, as well as the rising prevalence of ADHD diagnoses within this population. This study examined acute and chronic oral MPH effects on attention in male and female Wistar rats. To this end, we used a prepulse inhibition (PPI) task, which is widely used to assess psychoactive drug effects in both humans and rodents. This task allowed us to evaluate changes in attention by analyzing sensorimotor gating associated with stimulus selection process. METHODS: Animals were administered a clinically relevant dose of MPH (5 mg/kg) daily for seven days. The estrous cycle phases of the female rats were measured during behavioral sessions. The PPI task was conducted 20 min after drug administration on day 1 (acute), day 7 (chronic), and 48 h post-treatment. RESULTS: Results indicated that both acute and chronic MPH treatment impaired PPI expression in male rats, but not in female rats, regardless of their estrous cycle phase. Furthermore, a differential effect of chronic MPH treatment on the PPI task was found in male rats. Specifically, on the seventh treatment day, the PPI effect was observed when animals undertook the PPI task for the first time but was impaired in those animals in which the initial PPI session occurred under the acute influence of the drug (day 1). CONCLUSIONS: These findings suggest that the impact of MPH on sensorimotor gating responses may vary based on sex and task experience, possibly leading to state-dependent effects in healthy individuals.
Asunto(s)
Estimulantes del Sistema Nervioso Central , Metilfenidato , Humanos , Femenino , Masculino , Ratas , Animales , Metilfenidato/farmacología , Ratas Wistar , Estimulantes del Sistema Nervioso Central/farmacología , Inhibición Prepulso , Caracteres SexualesRESUMEN
BACKGROUND: This systematic mapping review aims to identify, describe, and organize the currently available evidence in systematic reviews (SR) and primary studies regarding orthognathic surgery (OS) co-interventions and surgical modalities, focusing on the outcomes blood loss, infection and relapse. MATERIAL AND METHODS: A comprehensive search strategy was performed to identify all SRs, randomized controlled trials and observational studies that evaluate surgical modalities and perioperative co-interventions in OS that evaluate the outcomes blood loss, infection and relapse, regardless of language or publication date. Searches were conducted in MEDLINE, EMBASE, Epistemonikos, Lilacs, Web of Science, and CENTRAL. In addition, grey literature was screened. RESULTS: 27 SRs and 150 primary studies fulfilled the inclusion criteria, 91 from SRs, and 59 from our search strategy. Overall, the quality of the SRs was graded as "Critically low," and only two SRs were rated as "High" quality. 11 PICO questions were extracted from SRs and 31 from primary studies, which focused on osteosynthesis methods, surgical cutting devices, use of antibiotics, and induced hypotension. In addition, evidence bubble maps for each outcome were created to analyze in a visual manner the existing evidence. CONCLUSIONS: Future primary and secondary high-quality research should be addressed focused on the eight knowledge gaps identified in this mapping review. We concluded that the evidence mapping approach is a practical methodology for organizing the current evidence and identifying knowledge gaps in OS, helping to reduce research waste and canalize future efforts in developing studies for unsolved questions.
Asunto(s)
Cirugía Ortognática , Humanos , Revisiones Sistemáticas como AsuntoRESUMEN
RATIONALE: Contemporary theories propose that latent inhibition (LI) is due to a process of interference with the context playing a key role as recovery cue. Physiological studies have demonstrated that LI is a process dependent on striatal dopamine. D2 dopamine receptors have been specifically associated with its expression, while D1 receptor has shown a limited function. However, to evaluate the role of dopamine receptors in LI, it is necessary to analyse their activity during recovery phase, where the mechanisms involved in interference processes are performed. OBJECTIVE: The experiments studied the involvement of the dopaminergic system in the retrieval process of LI. We analysed the effect of the systemic administration of dopaminergic D1 (SCH-23390) and D2 (sulpiride) antagonist during the test phase on LI and on its contextual specificity. METHODS: Animals were pre-exposed to saccharin solution and conditioned with a LiCl administration in conditioning phase. Dopaminergic antagonist drugs were administered during the test phase. Experiment 2 used the same context in all the phases. Experiment 3 used a new context during conditioning and test phase. RESULTS: The D2 antagonist increased the LI effect and, in turn, diminished the normally suppressant effect of the context shift on LI. The opposite effect was observed under the D1 antagonist administration. This drug disrupted LI and enhanced the effect that the context shift had on this cognitive process. CONCLUSIONS: D2 receptor had a relevant role on retrieval processes of pre-exposure learning, while D1 receptor was related with the contextual control of conditioning.
Asunto(s)
Antagonistas de los Receptores de Dopamina D2/farmacología , Inhibición Psicológica , Aprendizaje/efectos de los fármacos , Receptores de Dopamina D1/antagonistas & inhibidores , Receptores de Dopamina D1/fisiología , Receptores de Dopamina D2/fisiología , Animales , Benzazepinas/farmacología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/fisiología , Dopaminérgicos/farmacología , Aprendizaje/fisiología , Masculino , Ratas , Ratas Wistar , Sulpirida/farmacologíaRESUMEN
The latent inhibition phenomenon is observed when a conditioned stimulus is preexposed without any consequence before conditioning. The result of this manipulation is a reduction in conditioned response intensity to such a stimulus. In this study, we analyse the role of context novelty/familiarity on LI modulation by changing the context using a three-stage conditioned taste aversion procedure. Experiment 1 revealed that, similar to other learning procedures, a context change between preexposure and conditioning/testing (but not between preexposure/conditioning and testing) resulted in LI attenuation when the experimental contexts were novel. Experiment 2, using animals' home cages as one of the contexts, revealed a different pattern of results, with an unexpected increase in LI magnitude when the context change was introduced between conditioning and test stages. The Schmajuk et al. (1996) computational model explains these results in terms of the increased novelty of the conditioned stimulus during preexposure, conditioning, and testing.
Asunto(s)
Reacción de Prevención/fisiología , Condicionamiento Operante/fisiología , Ambiente , Reconocimiento en Psicología/fisiología , Gusto/fisiología , Análisis de Varianza , Animales , Conducta de Ingestión de Líquido/fisiología , Masculino , Ratas , Ratas Wistar , SacarinaRESUMEN
In mammals and birds, hippocampal processing is crucial for allocentric spatial learning. In these vertebrate groups, lesions to the hippocampal formation produce selective impairments in spatial tasks that require the encoding of relationships among environmental features, but not in tasks that require the approach to a single cue or simple non-spatial discriminations. In reptiles, a great deal of anatomical evidence indicates that the medial cortex (MC) could be homologous to the hippocampus of mammals and birds; however, few studies have examined the functional role of this structure in relation to learning and memory processes. The aim of this work was to study how the MC lesions affect spatial strategies. Results of Experiment 1 showed that the MC lesion impaired the performance in animals pre-operatively trained in a place task, and although these animals were able to learn the same task after surgery, probe test revealed that learning strategies used by MC lesioned turtles were different to that observed in sham animals. Experiment 2 showed that the MC lesion did not impair the retention of the pre-operatively learned task when a single intramaze visual cue identified the goal. These results suggest that the reptilian MC and hippocampus of mammals and birds function in quite similar ways, not only in relation to those spatial functions that are impaired, but also in relation to those learning processes that are not affected.
Asunto(s)
Aprendizaje Discriminativo/fisiología , Prosencéfalo/fisiología , Percepción Espacial/fisiología , Tortugas/fisiología , Animales , Corteza Cerebral/patología , Corteza Cerebral/fisiología , Hipocampo/fisiología , Práctica Psicológica , Prosencéfalo/patologíaRESUMEN
Many comparative pieces of research support the hypothesis that the medial cortex region of the reptilian forebrain could be homologous to hippocampal formation. Besides, there is some evidence involving this structure in complex spatial learning in a similar manner to hippocampus of mammals and birds. In this experiment we examined effects of medial cortex lesion in reversal learning. Turtles were trained in a spatial and a non-spatial maze procedure and the reversal of these tasks. Data revealed that sham and medial cortex lesioned turtles of both procedures performed well on the initial learning (acquisition). However, during the reversal phase, only the turtles with medial cortex lesion showed impaired performance in the spatial procedure. These results suggest that turtles possess different spatial learning and memory systems in close parallel to those described in other vertebrates, and that medial cortex plays a crucial role in complex place learning.
Asunto(s)
Corteza Cerebral/fisiología , Aprendizaje/fisiología , Trastornos de la Memoria/fisiopatología , Conducta Espacial/fisiología , Tortugas/fisiología , AnimalesRESUMEN
In mammals, the pallial amygdala is implicated in emotional learning and memory, whereas the hippocampus is involved in spatial, contextual, or relational memory. This review presents a set of experiments aimed to study the involvement of the dorsomedial and dorsolateral telencephalon of goldfish in spatial and active avoidance learning. Results showed that (1) medial lesions impaired both acquisition and retention of conditioned avoidance response in two-way active avoidance learning experiments with stimuli overlapping (emotional factor) and with an interstimuli gap (temporal and emotional factors), and (2) the medial lesion did not affect spatial learning (spatial, contextual, or relational factors). In contrast, lateral lesions did not impair conditioned avoidance response with stimuli overlapping, but affected conditioned avoidance response with an interstimuli gap and spatial learning. These results support the presence of two differentiated memory systems in teleost fish based on discrete pallial regions: emotional (dorsomedial telencephalon) and spatial/temporal or relational (dorsolateral telencephalon). Furthermore, these functional data support the homology between the medial pallium of the teleost and the pallial amygdala of land vertebrates, and between the teleost lateral pallium and the mammalian hippocampus.
Asunto(s)
Amígdala del Cerebelo/fisiología , Reacción de Prevención/fisiología , Carpa Dorada/fisiología , Aprendizaje/fisiología , Percepción Espacial/fisiología , Percepción del Tiempo/fisiología , AnimalesRESUMEN
The forebrain of vertebrates shows great morphological variation and specialized adaptations. However, an increasing amount of neuroanatomical and functional data reveal that the evolution of the vertebrate forebrain could have been more conservative than previously realized. For example, the pallial region of the teleost telencephalon contains subdivisions presumably homologous with various pallial areas in amniotes, including possibly a homologue of the medial pallium or hippocampus. In mammals and birds, the hippocampus is critical for encoding complex spatial information to form map-like cognitive representations of the environment. Here, we present data showing that the pallial areas of reptiles and fish, previously proposed as homologous to the hippocampus of mammals and birds on an anatomical basis, are similarly involved in spatial memory and navigation by map-like or relational representations of the allocentric space. These data suggest that early in vertebrate evolution, the medial pallium of an ancestral fish group that gave rise to the extant vertebrates became specialized for processing and encoding complex spatial information, and that this functional trait has been retained through the evolution of each independent vertebrate lineage.
Asunto(s)
Evolución Biológica , Hipocampo/fisiología , Memoria/fisiología , Percepción Espacial/fisiología , Vertebrados/fisiología , Animales , Peces/fisiología , Reptiles/fisiologíaRESUMEN
A new method is described for precise recording of eye movements in freely moving animals using Hall-effect devices. This inexpensive system, of small size and low weight, allows the analysis of horizontal and vertical components of saccadic eye movements, optokinetic nystagmus, slow tracking movements, eye vergence, etc., in unrestrained animals. A set of Hall-effect devices mounted in the skull is used to sense variations in the position of high-power miniature magnets fixed to the eye sclera. The output of the Hall-effect devices is amplified by operational amplifiers and collected through an analog-to-digital converter to be displayed on-line in a personal computer and stored for later analysis by specific software. Some examples of simultaneous body- and eye-movement recordings obtained in freely moving goldfish in different experimental situations are presented. This method would be useful in the recording of eye and gaze movements under natural conditions and for behavioural studies in freely moving animals.
Asunto(s)
Movimientos Oculares/fisiología , Animales , Recolección de Datos , Carpa Dorada/fisiología , Magnetismo , Nistagmo Optoquinético/fisiología , Movimientos Sacádicos/fisiología , TelemetríaRESUMEN
Spatial learning and memory related morphological changes in the argyrophilic nucleolar organizer region (AgNOR) of telencephalic neurons in goldfish were quantitatively evaluated by means of AgNOR neurohistochemical stain. The AgNORs and nuclei of nerve cells of two different telencephalic regions of goldfish trained in a spatial task or submitted to a similar non-contingent behavioral procedure (control group) were morphometrically evaluated. Results show that the area of AgNORs in goldfish dorsolateral telencephalic neurons increased significantly in the spatial learning group but not in control group. This effect seems to be highly specific as it did not appear in the dorsolateral area of the control group neither in the dorsomedial area of both groups. As the size of AgNORs in the nerve cell nuclei reflect the level of transcriptive activity, these morphological changes could be revealing increased protein synthesis in goldfish dorsolateral telencephalic neurons related with learning and memory. These findings could contribute to determining the subregions of the teleost telencephalon implicated in spatial learning and could indicate that the AgNOR staining technique would be a useful tool in assesing learning and memory related neuronal activity.
Asunto(s)
Carpa Dorada/anatomía & histología , Carpa Dorada/metabolismo , Aprendizaje/fisiología , Neuronas/citología , Neuronas/metabolismo , Región Organizadora del Nucléolo/metabolismo , Conducta Espacial/fisiología , Telencéfalo/citología , Telencéfalo/metabolismo , Animales , Conducta Animal/fisiología , Desempeño Psicomotor/fisiología , Tinción con Nitrato de Plata , Factores de TiempoRESUMEN
The present work investigated whether the fish telencephalon is involved in spatial learning based on place strategies in a manner similar to mammalian hippocampus. Goldfish were trained in a 4-arm maze in a room with relevant spatial cues. Sham and to-be-ablated subjects were trained in each of 4 experimental procedures designed as follows: place, turn, place-turn, and control. After acquisition, complete ablations of both telencephalic hemispheres for the experimental groups were carried out. The results showed that ablation exclusively impaired performance in animals using place strategies; in these, accuracy fell to chance level during both postsurgery retraining and reversal periods. In the other groups, ablation of the telencephalon did not induce any significant deficit. These results suggest that the fish telencephalon plays a crucial role in complex place learning.