Amanda Parker

Brain localization of memory chunks in chessplayers.

Chess experts store domain-specific representations in their long-term memory; due to the activation of such representations, they perform with high accuracy in tasks that require the maintenance of previously seen information. Chunk-based theories of expertise (chunking theory: ; template theory: ) state that expertise is acquired mainly by the acquisition and storage in long-term memory of familiar chunks that allow quick recognition. This study tested some predictions of these theories by using fMRI while chessplayers performed a recognition memory task. These theories predict that chessplayers access long-term memory chunks of domain-specific information, which are presumably stored in the temporal lobes. It was also predicted that the recognition memory tasks would activate working memory areas in the frontal and parietal lobes. These predictions were supported by the data.

Left lateralization in autobiographical memory: An fMRI study using the expert archival paradigm

In brain-imaging and behavioral research, studies of autobiographical memory have higher ecological validity than controlled laboratory memory studies. However, they also have less controllability over the variables investigated. This article presents a novel technique—the expert archival paradigm—that increases controllability while maintaining ecological validity. Stimuli were created from games played by two international-level chess masters. The two players were asked to perform a memory task with stimuli generated from their own games and stimuli generated from other players’ games while they were scanned using fMRI. The study found a left lateralized pattern of brain activity that was very similar in both masters. The brain areas activated were the left temporo-parietal junction and left frontal areas. The expert archival paradigm has the advantage of not requiring an interview to assess the participants’ autobiographical memories, and affords the possibility of measuring their accuracy of remembering as well as their brain activity related to remote and recent memories. It can also be used in any field of expertise, including arts, sciences, and sports, in which archival data are available.

Evolving Structure-Function Mappings in Cognitive Neuroscience Using Genetic Programming

A challenging goal of psychology and neuroscience is to map cognitive functions onto neuroanatomical structures. This paper shows how computational methods based upon evolutionary algorithms can facilitate the search for satisfactory mappings by efficiently combining constraints from neuroanatomy and physiology (the structures) with constraints from behavioural experiments (the functions). This methodology involves creation of a database coding for known neuroanatomical and physiological constraints, for mental programs made of primitive cognitive functions, and for typical experiments with their behavioural results. The evolutionary algorithms evolve theories mapping structures to functions in order to optimize the fit with the actual data. These theories lead to new, empirically testable predictions. The role of the prefrontal cortex in humans is discussed as an example. This methodology can be applied to the study of structures or functions alone, and can also be used to study other complex systems.

The L/M-opponent channel provides a distinct and time-dependent contribution towards visual recognition

The visual pathway has been successfully modelled as containing separate channels consisting of one achromatically opponent mechanism and two chromatically opponent mechanisms. However, little is known about how time affects the processing of chromatic information. Here, parametrically defined objects were generated. Reduced-colour objects were interleaved with full-colour objects and measures of recognition performance (d′) were compared by the continuous serial recognition paradigm. Measures were taken at multiple delay intervals (1, 4, 7, and 10 s). When chromatic variations were removed, recognition performance was impaired, but at the 1 s and 10 s intervals only. When luminance variations were removed, no impairment resulted. When only L/M-opponent modulations were removed, a deficit in performance was produced only at the 1 s and 10 s intervals, similar to the removal of chromatic variation. When only S-opponent modulations were removed, no impairment was observed. The results suggest that the L/M-opponent pathway provides a specialised contribution to visual recognition, but that its effect is modulated by time. A three-stage process model is proposed to explain the data.