Domain-specific and domain-general processes underlying metacognitive judgments

Metacognition and self-awareness are commonly assumed to operate as global capacities. However, there have been few attempts to test this assumption across multiple cognitive domains and metacognitive evaluations. Here, we assessed the covariance between “online” metacognitive processes, as measured by decision confidence judgments in the domains of perception and memory, and error awareness in the domain of attention to action. Previous research investigating metacognition across task domains have not matched stimulus characteristics across tasks raising the possibility that any differences in metacognitive accuracy may be influenced by local task properties. The current experiment measured metacognition in perceptual, memorial and attention tasks that were closely matched for stimulus characteristics. We found that metacognitive accuracy across the three tasks was dissociated suggesting that domain specific networks support an individual’s capacity for accurate metacognition. This finding was independent of objective performance, which was controlled using a staircase procedure. However, response times for metacognitive judgments and error awareness were associated suggesting that shared mechanisms determining how these meta-level evaluations unfold in time may underlie these different types of decision. In addition, the relationship between these laboratory measures of metacognition and reports of everyday functioning from participants and their significant others (informants) was investigated. We found that informant reports, but not self reports, predicted metacognitive accuracy on the perceptual task and participants who underreported cognitive difficulties relative to their informants also showed poorer metacognitive accuracy on the perceptual task. These results are discussed in the context of models of metacognitive regulation and neuropsychological evidence for dissociable metacognitive systems. The potential for the refinement of metacognitive assessment in clinical populations is also discussed.     

初级视觉皮层在表象表征方式研究中的作用

表象的信息表征方式一直是心理学研究的热点问题,脑成像技术在该问题的研究中发挥了巨大作用。本文以初级视觉皮层(V1)在表象表征方式研究中的作用为主线,系统梳理了基于脑成像技术开展的表象实质争论的核心问题,归纳分析了相关争论问题演绎发展的内在逻辑脉络,在此基础上指出了表象研究中需要进一步解决的关键问题,以期能够促进相关研究问题的进一步开展。     

Freeze-Frame: a new infant inhibition task and its relation to frontal cortex tasks during infancy and early childhood

The current study investigated a new, easily administered, visual inhibition task for infants termed the Freeze-Frame task. In the new task, 9-month-olds were encouraged to inhibit looks to peripheral distractors. This was done by briefly freezing a central animated stimulus when infants looked to the distractors. Half of the trials presented an engaging central stimulus, and the other half presented a repetitive central stimulus. Three measures of inhibitory function were derived from the task and compared with performance on a set of frontal cortex tasks administered at 9 and 24 months of age. As expected, infants' ability to learn to selectively inhibit looks to the distractors at 9 months predicted performance at 24 months. However, performance differences in the two Freeze-Frame trial types early in the experiment also turned out to be an important predictor. The results are discussed in terms of the validity of the Freeze-Frame task as an early measure of different components of inhibitory function.     

A social neuroscience perspective on adolescent risk-taking

This article proposes a framework for theory and research on risk-taking that is informed by developmental neuroscience. Two fundamental questions motivate this review. First, why does risk-taking increase between childhood and adolescence? Second, why does risk-taking decline between adolescence and adulthood? Risk-taking increases between childhood and adolescence as a result of changes around the time of puberty in the brain’s socio-emotional system leading to increased reward-seeking, especially in the presence of peers, fueled mainly by a dramatic remodeling of the brain’s dopaminergic system. Risk-taking declines between adolescence and adulthood because of changes in the brain’s cognitive control system—changes which improve individuals’ capacity for self-regulation. These changes occur across adolescence and young adulthood and are seen in structural and functional changes within the prefrontal cortex and its connections to other brain regions. The differing timetables of these changes make mid-adolescence a time of heightened vulnerability to risky and reckless behavior.     

The role of white matter hyperintensities and medial temporal lobe atrophy in age-related executive dysfunctioning

Various studies support an association between white matter hyperintensities (WMH) and deficits in executive function in nondemented ageing. Studies examining executive functions and WMH have generally adopted executive function as a phrase including various functions such as flexibility, inhibition, and working memory. However, these functions include distinctive cognitive processes and not all may be affected as a result of WMH. Furthermore, atrophy of the medial temporal lobe (MTA) is frequently observed in ageing. Nevertheless, in previous studies of nondemented ageing MTA was not considered when examining a relationship between white matter and executive function. The goal of the present study was to examine how WMH and MTA relate to a variety of executive functions, including flexibility, fluency, inhibition, planning, set shifting, and working memory. Strong correlations were observed between WMH and MTA and most of the executive functions. However, only MTA was related to flexibility and set shifting performance. Regression analysis furthermore showed that MTA was the strongest predictor of working memory, after which no further significant association with WMH was noted. Alternatively, both MTA and periventricular hyperintensities independently predicted inhibition performance. These findings emphasize the importance of MTA when examining age-related decline in executive functioning.     

Acetylcholine esterase activity and behavioral response in hypoxia induced neonatal rats: effect of glucose, oxygen and epinephrine supplementation

Brain damage due to an episode of hypoxia remains a major problem in infants causing deficit in motor and sensory function. Hypoxia leads to neuronal functional failure, cerebral palsy and neuro-developmental delay with characteristic biochemical and molecular alterations resulting in permanent or transitory neurological sequelae or even death. During neonatal hypoxia, traditional resuscitation practices include the routine administration of 100% oxygen, epinephrine and glucose. In the present study, we assessed the changes in the cholinergic system by measuring the acetylcholinesterase (AChE) activity and the behavioral responses shown by hypoxia induced neonatal rats and hypoxic rats supplemented with glucose, oxygen and epinephrine using elevated plus-maze and open-field test. The acetylcholine esterase enzyme activity showed a significant decrease in cerebral cortex, whereas it increased significantly in the muscle of experimental rats when compared to control. Hypoxic rats supplemented with glucose, glucose and oxygen showed a reversal to the control status. Behavioral studies were carried out in experimental rats with elevated plus-maze test and open-field test. Hypolocomotion and anxiogenic behavioral responses were observed in all experimental rats when compared to control, hypoxic rats supplemented with glucose, glucose and oxygen. Thus, our results suggest that brain damage due to hypoxia, oxygen and epinephrine supplementation in the neonatal rats cause acetylcholine-neuromuscular-defect leading to hypolocomotion and anxiogenic behavioral response. Glucose and glucose with oxygen supplementation to hypoxic neonates protect the brain damage for a better functional status in the later life.     

Declarative Memory

ABSTRACT— Neuroimaging of declarative memory is not an endeavor divorced from psychology but, instead, is another path through which a more complete understanding of memory has emerged. Specifically, neuroimaging allows us to determine if differences between memory states emerge from quantitatively or qualitatively distinct underlying encoding operations. Further, it has allowed for greater specification of the putative control operations adopted when we make decisions about our memories. We describe some examples of insights provided by neuroimaging into the many and varied processes that support encoding and retrieval of declarative memory.     

Coherence and recurrency: maintenance,control and integration in working memory

Working memory (WM), including a ‘central executive’, is used to guide behavior by internal goals or intentions. We suggest that WM is best described as a set of three interdependent functions which are implemented in the prefrontal cortex (PFC). These functions are maintenance, control of attention and integration. A model for the maintenance function is presented, and we will argue that this model can be extended to incorporate the other functions as well. Maintenance is the capacity to briefly maintain information in the absence of corresponding input, and even in the face of distracting information. We will argue that maintenance is based on recurrent loops between PFC and posterior parts of the brain, and probably within PFC as well. In these loops information can be held temporarily in an active form. We show that a model based on these structural ideas is capable of maintaining a limited number of neural patterns. Not the size, but the coherence of patterns (i.e., a chunking principle based on synchronous firing of interconnected cell assemblies) determines the maintenance capacity. A mechanism that optimizes coherent pattern segregation, also poses a limit to the number of assemblies (about four) that can concurrently reverberate. Top-down attentional control (in perception, action and memory retrieval) can be modelled by the modulation and re-entry of top-down information to posterior parts of the brain. Hierarchically organized modules in PFC create the possibility for information integration. We argue that large-scale multimodal integration of information creates an ‘episodic buffer’, and may even suffice for implementing a central executive.