Modulation of frontal lobes activity is believed to be an important pathway trough which the hypothalamic-pituitary-adrenal (HPA) axis stress response impacts cognitive and emotional functioning. Here, we investigate the effects of stress on metacognition, which is the ability to monitor and control one's own cognition. As the frontal lobes have been shown to play a critical role in metacognition, we predicted that under activation of the HPA axis, participants should be less accurate in the assessment of their own performances in a perceptual decision task, irrespective of the effect of stress on the first order perceptual decision itself. To test this prediction, we constituted three groups of high, medium and low stress responders based on cortisol concentration in saliva in response to a standardized psycho-social stress challenge (the Trier Social Stress Test). We then assessed the accuracy of participants' confidence judgments in a visual discrimination task. As predicted, we found that high biological reactivity to stress correlates with lower sensitivity in metacognition. In sum, participants under stress know less when they know and when they do not know.
In clinical cases of amnesia that followed bilateral excisions of medial temporal lobe structures, with some perceptual learning abilities intact, damage to the hippocampus was presumed to be the critical factor. The authors' search for an animal model of amnesia, based on ablations aimed at the hippocampal formation in infant rhesus monkeys, provides support for this view. Ablations of the hippocampal formation in 2-month-old infants tested shortly after recovery from surgery resulted in a deficit on a recognition memory task but left intact the ability to learn the concurrent object discrimination task, even though the latter task was administered with the use of a massed practice procedure. Thus, early damage, unlike that at 2 years of age or later, allowed the authors to dissociate associative learning with repeated trials, independent of hippocampal functions and recognition memory that depends on the integrity of the hippocampus.
Resumeneste artículo presenta una breve reseña sobre el Deterioro cognitivo leve en adultos mayores, considerando los principales precursores que anuncian, y los factores de riesgo que aceleran los procesos de envejecimiento cognitivo, los cuales aumentan la probabilidad de recibir un diagnóstico de Dcl. a su vez, la presencia de Dcl aumenta el riesgo y eventual tránsito hacia la demencia, especialmente la demencia de tipo alzheimer. por otra parte, en el artículo se describen las diferentes modalidades de presentación del deterioro cognitivo, revisando también el Dcl asociado a la sintomatología depresiva, a la enfermedad de parkinson y otras enfermedades degenerativas del sNc. la presente revisión, permite dar cuenta de hallazgos recientes y relevantes con relación a la disfunción cognitiva en adultos mayores, quienes representan una proporción cada vez mayor de la población nacional y mundial. Palabras clave: envejecimiento, deterioro cognitivo leve, indicadores tempranos, demencia Abstract this article presents a brief overview of mild cognitive impairment in older adults, considering its main anticipating precursors, and the risk factors that may accelerate the processes of cognitive aging, which increases the likelihood of being diagnosed with Mci. in turn, the presence of Mcl increases the risk and eventual transition to dementia, particularly alzheimer's dementia. Moreover, the article describes the different forms cognitive impairment may present itself, and also reviews MCI associated with depressive symptoms, parkinson's disease and other degenerative diseases of the cNs. this revision accounts for recent and relevant findings regarding cognitive dysfunction in the elderly, who represent a growing share of national and global populations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.