This article examines the anatomy and circuitry of skills that, like reading, calculating, recognizing, or remembering, are common abilities of humans. While the anatomical areas active are unique to each skill there are features common to all tasks. For example, all skills produce activation of a small number of widely separated neural areas that appear necessary to perform the task. These neural areas relate to internal codes that may not be observed by any external behavior nor be reportable by the performer. There is considerable plasticity to the performance of skills. Task components can be given priority through attention, which serves to increase activation of the relevant brain areas. Attention can also cause reactivation of sensory areas driven by input, but usually only after a delay. The threshold for activation for any area may be temporarily reduced by prior activation (priming or practice). Skill components requiring attention tend to cause interference resulting in the dual tasks effects and unified focus of attention described in many cognitive studies. Practice may change the size or number of brain areas involved and alter the pathways used by the skill. By combining cognitive and anatomical analyses, a more general picture of the nature of skill emerges.

Brain↗

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Cognition and neural systems.

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Animals↗

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Topography of the N400: brain electrical activity reflecting semantic expectancy.

When subjects read an semantically unexpected word, the brain electrical activity shows a negative deflection at about 400 msec in comparison with the response to an expected word. In order to study the brain systems related to this effect we mapped it with a dense (64-channel) electrode array and two reference-independent measures, one estimating the average potential gradients and the other radial current density. With these measures, the event-related brain potential (ERP) begins at about 70 msec with the P1, reflecting bilateral current sources over occipitoparietal areas. A strongly left-lateralized N1 then follows, peaking at about 180 msec, accompanied by an anterior positivity, the P2. A separate posterior positive pattern then emerges that seems to repeat the topography of the P1. Next, at about 350 msec, the ERP for the congruous word develops a P300 or LPC, characterized by a diffuse positivity over the superior surface of the head and several negativities over inferior regions. This superior source/inferior sink pattern of the LPC is greater over the left hemisphere. In contrast, the ERP for the incongruous word in this interval displays the N400 as a period in which topographic features are absent. At about 400 msec the ERP for the incongruous word begins to develop an LPC, which then remains relatively symmetric over the two hemispheres.

Analysis of Variance↗

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Localizing cognitive operations.

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Brain↗

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Development of brain networks for orienting to novelty.

Among the many contributions of I.P. Pavlov to the study of the higher nervous system was his exploration of the physical basis of attention. Pavlov's analysis of the orienting reflex (OR), together with the contributions of Y.N. Sokolov, demonstrated that attention could be studies by the objective methods of neurophysiology. Cognitive neuroscience has continued these effort by using neuroimaging to explore the anatomy and physiology of attention in the working human brain. It is now possible to show that the appearance of a novel visual event invokes multiple attentional networks that work in concert to orient to and process a novel object within a very brief exposure. In this paper, we describe cognitive studies of orienting to novelty in adults, examine the networks of neural areas involved in processing novel objects, and review the development in early life of these attentional networks. Orienting to novelty provides an excellent vehicle for examining how biology and experience shape the mechanisms of self-regulation and cognitive control.

Attention↗