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Abstract The control of some physiological parameters, such as the heart rate, is known to have a role in cognitive and emotional processes. Cardiac changes are also linked to mental health issues and neurodegeneration. Thus, it is not surprising that many of the brain structures typically associated with cognition and emotion also comprise a circuit—the central automatic network—responsible for the modulation of cardiovascular output. The mediodorsal thalamus (MD) is involved in higher cognitive processes and is also known to be connected to some of the key neural structures that regulate cardiovascular function. However, it is unclear whether the MD has any role in this circuitry. Here, we show that discrete manipulations (microstimulation during anaesthetized functional neuroimaging or localized cytotoxin infusions) to either the magnocellular or the parvocellular MD subdivisions led to observable and variable changes in the heart rate of female and male rhesus macaque monkeys. Considering the central positions that these two MD subdivisions have in frontal cortico-thalamocortical circuits, our findings suggest that MD contributions to autonomic regulation may interact with its identified role in higher cognitive processes, representing an important physiological link between cognition and emotion.

It has been argued that perception, decision making, and movement planning are in reality tightly interwoven brain processes. However, how they are implemented in neural circuits is still a matter of debate. We tested human subjects in a temporal categorization task in which intervals had to be categorized as short or long. Subjects communicated their decision by moving a cursor into one of two possible targets, which appeared separated by different angles from trial to trial. Even though there was a 1 second-long delay between interval presentation and decision communication, categorization difficulty affected subjects' performance, reaction (RT) and movement time (MT). In addition, reaction and movement times were also influenced by the distance between the targets. This implies that not only perceptual, but also movement-related considerations were incorporated into the decision process. Therefore, we searched for a model that could use categorization difficulty and target separation to describe subjects' performance, RT, and MT. We developed a network consisting of two mutually inhibiting neural populations, each tuned to one of the possible categories and composed of an accumulation and a memory node. This network sequentially acquired interval information, maintained it in working memory and was then attracted to one of two possible states, corresponding to a categorical decision. It faithfully replicated subjects' RT and MT as a function of categorization difficulty and target distance; it also replicated performance as a function of categorization difficulty. Furthermore, this model was used to make new predictions about the effect of untested durations, target distances and delay durations. To our knowledge, this is the first biologically plausible model that has been proposed to account for decision making and communication by integrating both sensory and motor planning information.

La hipertensión arterial esencial (HTE) es uno de los principales factores de riesgo cardiovascular y generador indirecto de la enfermedad coronaria, la mayor causa de muertes en Colombia y el mundo [1].El Sistema Nervioso Simpático (SNS) modifica la resistenciaarterial periférica a través del receptor ? 2 adrenérgico, generando señales intracelulares que regulan la relajación delmúsculo liso vascular. Este receptor experimenta un procesodenominado desensibilización, es decir, cuando es activado porun agonista por tiempo prolongado, la respuesta no será de lamisma intensidad a la inicial. La desensibilización del receptor? 2 parece estar determinada por la estructura de aminoácidospolimórficos: Arginina 16 Glicina y Ácido glutámico 27 Glutaminaamino terminales. Estas variantes son codificadas por polimorfismos de un solo nucleótido (SNP) 46 y 79. La funciónde estos polimorfismos y su efecto en la función vascular escontroversial. Evidencias clínica e in vitro sugieren que la Glicina16 se desensibiliza mas rápido que la Arginina; igualmente, elÁcido glutámico 27 facilita la desensibilización versusglutamina[2].