High temporal resolution event-related brain potential and electroencephalographic coherence studies of the neural substrate of short-term storage in working memory indicate that the sustained coactivation of both prefrontal cortex and the posterior cortical systems that participate in the initial perception and comprehension of the retained information are involved in its storage. These studies further show that short-term storage mechanisms involve an increase in neural synchrony between prefrontal cortex and posterior cortex and the enhanced activation of long-term memory representations of material (...) held in short-term memory. This activation begins during the encoding/comprehension phase and evidently is prolonged into the retention phase by attentional drive from prefrontal cortex control systems. A parsimonious interpretation of these findings is that the long-term memory systems associated with the posterior cortical processors provide the necessary representational basis for working memory, with the property of short-term memory decay being primarily due to the posterior system. In this view, there is no reason to posit specialized neural systems whose functions are limited to those of short-term storage buffers. Prefrontal cortex provides the attentional pointer system for maintaining activation in the appropriate posterior processing systems. Short-term memory capacity and phenomena such as displacement of information in short-term memory are determined by limitations on the number of pointers that can be sustained by the prefrontal control systems. Key Words: coherence; event-related potentials; imaging; long-term memory; memory; short-term memory; working memory. (shrink)
Two paradigms have guided emotion research over the past decades. The dual-system view embraces the long-held Western belief, espoused most prominently by decision-making and social cognition researchers, that emotion and reason are often at odds. The integrative view, which asserts that emotion and cognition work synergistically, has been less explored experimentally. However, the integrative view (a) may help explain several findings that are not easily accounted for by the dual-system approach, and (b) is better supported by a growing body of (...) evidence from human neuroanatomy that has often been overlooked by experimental neuroscience. (shrink)
We tested an architect with a lesion to the right prefrontal cortex in a real-world architectural design/planning task that required him to develop a new design for our lab space and compared his performance to an age- and education-matched architect. The patient understood the task and even observed that this is a very simple problem. His sophisticated architectural knowledge base was still intact and he used it quite skilfully during the problem structuring phase. However, the patient's problem-solving behaviour differed from (...) the control's behaviour in the following ways: he was unable to make the transition from problem structuring to problem solving; as a result preliminary design did not start until two thirds of the way into the session; the preliminary design phase was minimal and erratic, consisting of three independently generated fragments; there was no progression or lateral development of these fragments; there was no carry-over of abstract information into the preliminary design or later phases, and the patient did not make it to the detailing phase. This suggests that the key to understanding our patient's deficit is to understand the cognitive processes and mechanisms involved in the preliminary design phase. We appeal to a theory of design problem solving that associates cognitive processes involved in preliminary design with lateral state transformations and argues that ill-structured representational and computational systems are necessary to support these transformations. We conclude that the neural basis of this system is selectively damaged in our patient. (shrink)
We respond to Farah (1994) by making some general remarks about information encapsulation and locality and asking how these are violated in her computational models. Our point is not that we disagree, but rather that Farah's treatment of the issues is not sufficiently rigorous to allow an evaluation of her claims.
Rolls emphasizes the role of emotion in behavior. My commentary provides some balance to that position by arguing that stored social knowledge dominates our behavior and controls emotional states, thereby reducing emotions to a subservient role in behavior.
Instead of endorsing an all-encompassing view about the influence of abstractions in predictive processing, I suggest that most deliberative thought including complex abstractions, agent actions, and/or perceived environmental sequences are stored in the human prefrontal cortex in the form of structured event complexes.
The goal of our target article is to establish that electrophysiological data constrain models of short-term memory retention operations to schemes in which activated long-term memory is its representational basis. The temporary stores correspond to neural circuits involved in the perception and subsequent processing of the relevant information, and do not involve specialized neural circuits dedicated to the temporary holding of information outside of those embedded in long-term memory. The commentaries ranged from general agreement with the view that short-term memory (...) stores correspond to activated long-term memory (e.g., Abry, Sato, Schwartz, Loevenbruck & Cathiard [Abry etal.], Cowan, Fuster, Grote, Hickok & Buchsbaum, Keenan, Hyönä & Kaakinen [Keenan et al.], Martin, Morra), to taking a definite exception to this view (e.g., Baddeley, Düzel, Logie & Della Sala, Kroger, Majerus, Van der Linden, Colette & Salmon [Majerus et al.], Vallar). (shrink)
Parkinson's disease patients receiving dopaminergic treatment may experience bursts of creativity. Although this phenomenon is sometimes recognized among patients and their clinicians, the association between dopamine replacement therapy in PD patients and creativity remains underexplored. It is unclear, for instance, whether DRT affects creativity through convergent or divergent thinking, idea generation, or a general lack of inhibition. It is also unclear whether DRT only augments pre-existing creative attributes or generates creativity de novo. Here, we tested a group of PD patients (...) when “on” and “off” dopaminergic treatment on a series of tests of creative problem-solving, and related their performance to a group of matched healthy controls as well as to their pre-PD creative skills and measures of inhibition/impulsivity. Results did not provide strong evidence that DRT improved creative thinking in PD patients. Rather, PD patients “on” medication showed less flexibility in divergent thinking, generated fewer ideas via insight, and showed worse performance in convergent thinking overall than healthy controls. Pre-PD creative skills predicted enhanced flexibility and fluency in divergent thinking when PD patients were “on” medication. However, results on convergent thinking were mixed. Finally, PD patients who exhibited deficits in a measure of inhibitory control showed weaker convergent thinking while “on” medication, supporting previous evidence on the importance of inhibitory control in creative problem-solving. Altogether, results do not support the hypothesis that DRT promotes creative thinking in PD. We speculate that bursts of artistic production in PD are perhaps conflated with creativity due to lay conceptions of creativity. (shrink)
Moral judgment is a complex cognitive process that partly depends upon social and individual cultural values. There have been various efforts to categorize different aspects of moral judgment, but most studies depend upon rare dilemmas. We recruited 25 subjects from Tehran, Iran, to rate 150 everyday moral scenarios developed by Knutson et al. Using exploratory factor analysis, we observed that the same moral dimensions were driven by the same moral cognitive factors in Iranian vs. American studies. However, there were minor (...) differences in the factor loadings between the two cultures. Furthermore, based on the EFA results, we developed a short form of the questionnaire by removing eleven of the fifteen scenarios from each of the ten categories. These results could be used in further studies to better understand the similarities and differences in moral judgment in everyday interactions across different cultures. (shrink)