We review evidence for partially segregated networks of brain areas that carry out different attentional functions. One system, which includes parts of the intraparietal cortex and superior frontal cortex, is involved in preparing and applying goal-directed (top-down) selection for stimuli and responses. This system is also modulated by the detection of stimuli. The other system, which includes the temporoparietal cortex and inferior frontal cortex, and is largely lateralized to the right hemisphere, is not involved in top-down selection. Instead, this system is specialized for the detection of behaviourally relevant stimuli, particularly when they are salient or unexpected. This ventral frontoparietal network works as a 'circuit breaker' for the dorsal system, directing attention to salient events. Both attentional systems interact during normal vision, and both are disrupted in unilateral spatial neglect.

Control of goal-directed and stimulus-driven attention in the brain

Publisher Summary This chapter focuses on the modern notion of short-term memory, called working memory. Working memory refers to the temporary maintenance of information that was just experienced or just retrieved from long-term memory but no longer exists in the external environment. These internal representations are short-lived, but can be maintained for longer periods of time through active rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goal-directed behavior. Working memory is a system that is critically important in cognition and seems necessary in the course of performing many other cognitive functions, such as reasoning, language comprehension, planning, and spatial processing. This chapter demonstrates the functional importance of dopamine to working memory function in several ways. Elucidation of the cognitive and neural mechanisms underlying human working memory is an important focus of cognitive neuroscience and neurology for much of the past decade. One conclusion that arises from research is that working memory, a faculty that enables temporary storage and manipulation of information in the service of behavioral goals, can be viewed as neither a unitary, nor a dedicated system. Data from numerous neuropsychological and neurophysiological studies in animals and humans demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.

Chapter 11 Working memory

https://surfer.nmr.mgh.harvard.edu/ftp/articles/desikan06-parcellation.pdf

An automated labeling system for subdividing the human cerebral cortex on MRI scans into gyral based regions of interest.

Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Using functional magnetic resonance imaging (fMRI), we found an area in the fusiform gyrus in 12 of the 15 subjects tested that was significantly more active when the subjects viewed faces than when they viewed assorted common objects. This face activation was used to define a specific region of interest individually for each subject, within which several new tests of face specificity were run. In each of five subjects tested, the predefined candidate “face area” also responded significantly more strongly to passive viewing of (1) intact than scrambled two-tone faces, (2) full front-view face photos than front-view photos of houses, and (in a different set of five subjects) (3) three-quarter-view face photos (with hair concealed) than photos of human hands; it also responded more strongly during (4) a consecutive matching task performed on three-quarter-view faces versus hands. Our technique of running multiple tests applied to the same region defined functionally within individual subjects provides a solution to two common problems in functional imaging: (1) the requirement to correct for multiple statistical comparisons and (2) the inevitable ambiguity in the interpretation of any study in which only two or three conditions are compared. Our data allow us to reject alternative accounts of the function of the fusiform face area (area “FF”) that appeal to visual attention, subordinate-level classification, or general processing of any animate or human forms, demonstrating that this region is selectively involved in the perception of faces.

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The Fusiform Face Area: A Module in Human Extrastriate Cortex Specialized for Face Perception

Cognitive neuroscientists have acquired powerful new tools for studying the functional neuroanatomy of the human brain. Traditional methods such as lesion analysis have been supplemented with electrical and mag netic field recording techniques that can measure the informational transactions of the brain in the scale of milliseconds and neuroimaging techniques that can provide structural details of the brain to a fraction of a millimeter. The most powerful new methods have been functional imaging techniques in which brain activity engendered by a sensory, motor, or cognitive task causes an increase in local blood flow and metabolism that can be imaged with high resolution. This article reviews recent progress in functional neuroimaging, with special emphasis on understanding the neural substrates of memory. The Neuroscientist 1:155-163, 1995

Review : Functional Neuroimaging of Memory

The influence of emotional distraction on verbal working memory: an fMRI investigation comparing individuals with schizophrenia and healthy adults.

Research about the neural basis of face recognition has investigated the timing and anatomical substrates of different stages of face processing. Scalp-recorded ERP studies of face processing have ...

The Effects of Face Inversion and Face Race on the P100 ERP

Using functional magnetic resonance imaging (fMRI), we investigated brain activity in an observer who watched the hand and arm motions of an individual when that individual was, or was not, the cause of the motion. Subjects viewed a realistic animated 3D character who sat at a table containing four pistons. On Intended Motion trials, the character raised his hand and arm upwards. On Unintended Motion trials, the piston under one of the character's hands pushed the hand and arm upward with the same motion. Finally, during Non-Biological Motion control trials, a piston pushed a coffee mug upward in the same smooth motion. Hand and arm motions, regardless of intention, evoked significantly more activity than control trials in a bilateral region that extended ventrally from the posterior superior temporal sulcus (pSTS) region and which was more spatially extensive in the right hemisphere. The left pSTS near the temporal-parietal junction, robustly differentiated between the Intended Motion and Unintended Motion conditions. Here, strong activity was observed for Intended Motion trials, while Unintended Motion trials evoked similar activity as the coffee mug trials. Our results demonstrate a strong hemispheric bias in the role of the pSTS in the perception of causality of biological motion.

Perceived causality influences brain activity evoked by biological motion.

The electrical activity of the brain has always tantalized investigators interested in developing a psychobiology of consciousness. Hans Berger had been driven to his pioneering studies of the human electroencephalogram (EEG) by his interest in “psychic energy.” Jung (1975) reported that Berger “believed that the chemical energy of brain metabolism was transported into heat, electrical and ‘psychic’ energy, and he hoped to extrapolate the latter by measuring the heat production and electrical activity of the brain” (p. 484). The EEG, which Berger discovered, promised to allow insights into the mechanisms underlying consciousness. The rationale for this promise is evident. Because the phenomena of consciousness make themselves most readily available in the human, consciousness is best studied in the awake, alert, speaking individual. As electrical brain activity is one of the few means available for the observation of neural activity in the intact human, it is a natural object of interest to the student of consciousness.

Gregory McCarthy

Papers

Review : Functional Neuroimaging of Memory

The influence of emotional distraction on verbal working memory: an fMRI investigation comparing individuals with schizophrenia and healthy adults.

The Effects of Face Inversion and Face Race on the P100 ERP

Perceived causality influences brain activity evoked by biological motion.

Event-Related Brain Potentials in the Study of Consciousness