I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Principles of Neural Science

Recent studies of eye movements in reading and other information processing tasks, such as music reading, typing, visual search, and scene perception, are reviewed. The major emphasis of the review is on reading as a specific example of cognitive processing. Basic topics discussed with respect to reading are (a) the characteristics of eye movements, (b) the perceptual span, (c) integration of information across saccades, (d) eye movement control, and (e) individual differences (including dyslexia). Similar topics are discussed with respect to the other tasks examined. The basic theme of the review is that eye movement data reflect moment-to-moment cognitive processes in the various tasks examined. Theoretical and practical considerations concerning the use of eye movement data are also discussed.

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Eye movements in reading and information processing: 20 years of research.

Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. How- ever, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide vari- ety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recoding of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity- limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed.

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The magical number 4 in short-term memory: a reconsideration of mental storage capacity.

Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus failing to account for the goal-directedness of even the simplest reaction in an experimental task We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0140525X01000103

The Theory of Event Coding (TEC): a framework for perception and action planning.

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual \"filling in,\" visual stability despite eye movements, change blindness, sensory substitution, and color perception.

A sensorimotor account of vision and visual consciousness-Authors' Response-Acting out our sensory experience

Neuro-CognitivePsychology, Bielefeld University, Bielefeld 33501, GermanyA well-known theory in the ﬁeld of attention today is the premotortheory of attention which suggests that the mechanisms involved ineye movements are the same as those for spatial attention shifts.We tested a parietal damaged patient with unilateral optic ataxiaand 4 controls on a dual saccade/attentional task and showa dissociation between saccadic eye movements and presaccadicperceptual enhancement at the saccade goal. Remarkably, thoughthe patient was able to make the appropriate saccades to the left,impaired visual ﬁeld (undistinguishable from saccades to his right,intact visual ﬁeld), he was unable to discriminate the letter at thesaccade goal (whereas his performance was like controls for letterdiscrimination in his right visual ﬁeld). This suggests that saccadeplanning and presaccadic perceptual facilitation are separable—planning a saccade to a location does not necessitate that theprocessing of this location is enhanced. Based on these results, wesuggest that the parietal cortex is necessary for the couplingbetween saccade planning and presaccadic perceptual facilitation.Keywords: attention, optic ataxia, parietal cortex, saccadesIntroductionEye movements and attention are very closely related.Normally, when we want to pay attention to an object, wemove our eyes so as to foveate on it (i.e., we shift our gaze) andthis is known as overt attention. However, it is also possible toshift attention without moving the eyes. This process is knownas covert attention. Both overt and covert attention have thesame objective: to enhance a location in space for furtherprocessing, either by bringing the object into higher-precisionprocessing pathways associated with central vision (Anstis1998), or by enhancing the efﬁciency of the processing inperipheral vision selectively at this speciﬁc location (Bushnellet al. 1981).According to the premotor theory of attention (Rizzolatti1983; Rizzolatti et al. 1987, 1994), a command to shift attentionis the same as a command to shift gaze. In both cases, attentionis shifted (covertly or overtly). This theory suggests thatpreparing a saccade to a peripheral target location involves thesame process as orienting selective attention to this peripherallocation, except that this process is then followed by the motorexecution. Inversely, any saccade will be associated witha spatially speciﬁc enhancement of processing at the locationof the saccade goal, i.e. saccades to a spatial location cannotoccur without a previous shift of attention to the location(Hoffman and Subramaniam 1995; Kowler et al. 1995; Goldberget al. 2006). In a behavioral study, Deubel and Schneider (1996)tested subjects’ ability to discriminate letter symbols atlocations around or at the saccade target location, beforesaccadic execution. They found that letter discrimination wasbest when it was in the same position as the saccade goal. Theability to discriminate a letter at any location other than thegoal of the saccade decreased to chance level. By showing thatwhen a saccade is executed toward a peripheral target, it ispreceded by a phenomenon of ‘‘presaccadic facilitation’’ ofletter discrimination speciﬁcally at this precise peripherallocation, this paradigm conﬁrmed the spatial and temporalrelationship between saccades and attention: attention isoriented before saccadic execution toward the speciﬁc locationof the saccade goal, and may thus share common mechanismswith saccadic preparation (Schneider and Deubel 2002).Central to this theory is the ﬁnding that the same areas in thebrain that are involved in gaze or eye movements are alsoinvolved in attention shifts (Ignashchenkova et al. 2004; Mooreand Fallah 2004; Goldberg et al. 2006). One of the key areasshown to be involved in both attention and saccadic eyemovements is the lateral intraparietal area (LIP) in the monkeyposterior parietal cortex (Goldberg et al. 2006). We thereforetested involvement of the parietal cortex in the couplingbetween presaccadic attentional shifts and eye movements byobserving the performance of a patient with unilateral opticataxia due to damage to the right posterior parietal cortex. Ifsaccade planning and attentional shifts involve the samemechanisms, we should ﬁnd a similar pattern of performancein target discrimination and saccade execution to the damagedvisual ﬁeld. On the other hand, a dissociation between saccadicperformance and target discrimination performance couldsuggest that separate neural substrates govern attention andsaccade planning, but those processes could be coupled andoccur simultaneously. A second possibility could be that theparietal cortex mediates the coupling between a network ofareas involved in saccade planning and presaccadic facilitation,such as frontal and temporal areas. In normal behavior, it isimpossible to distinguish between a coupling and a commonsubstrate, however the impaired region/pathways in thispatient may provide valuable insight into these mechanisms.We tested the patient and 4 control subjects on a simpliﬁedversion of the task used by Deubel and Schneider (1996). In ourtask the saccade was always directed to the same location (at10 visual degrees of eccentricity) leftward or rightward.Subjects were then required to discriminate letters presentedbrieﬂy during the saccade latency either at the saccade goal orat nonsaccade goal locations 3 closer or further away in thesame visual ﬁeld. This task allowed us to test the presence ofpresaccadic facilitation, 1) at the location of the saccade goaland 2) at surrounding locations, testing for potential spatialdistortions in attentional shifts. Spatial distortions have been

Parietal Damage Dissociates Saccade Planning from Presaccadic Perceptual Facilitation

Subjects in eye movement experiments sometimes report that they have moved their eyes to some location before their eyes have actually moved (Deubel and Schneider, 1996). We investigated this by presenting a brief test stimulus at various points in time after directing subjects to make a saccadic eye movement to a peripheral cue. The subjects had to report where they were looking when the test stimulus was presented. We found that visual stimuli presented at the saccade target location as early as 250 ms before sac-cade onset were reported as occurring after the saccade. In a second experiment subjects performed, intentionally, a saccade to a static cue. Also under this condition, subjects reported to look at the future saccade target location long before the saccade actually occurred. The data show that subjects are unaware of the time when they make even a large saccade, and that they have no explicit knowledge of the retinal position of stimuli. Rather, they mistake movements of visual attention for movements of the eyes.

The Subjective Direction of Gaze Shifts Long Before the Saccade

Perceiving temporal simultaneity of cross-modal (e.g., visuo-haptic) events is very important for coherent perception and high performance in multi-modal interaction (e.g. telepresence) systems. The perception of simultaneity, however, depends on many factors, including stimulus intensity, redundant information and selective attention. In this study, we examined the effects of two factors on perceived simultaneity in a visuo-haptic task scenario: active (self- generated) motor control and additional visual motion feedback. We used a psychophysical method to measure the differences in points of subjective simultaneity (PSSs) and just noticeable differences (JNDs) in visuo-haptic events. The results showed that the PSS decreased significantly under conditions of active motor control with concurrent visual feedback, and the JNDs were narrowed with either active motor control or additional visual motion feedback.

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Influence of visuomotor action on visual-haptic simultaneous perception: A psychophysical study

Human vision is characterized by a consistent pattern of saccadic eye movements. With each saccade, internal object representations change their retinal position and spatial resolution. This raises the question as to how peripheral perception is affected by imminent saccadic eye movements. Here, we suggest that saccades are accompanied by a predictionoftheirperceptualconsequences(i.e.,thefoveationofthetargetobject).Accordingly,peripheralperception should be biased toward previously associated foveal input. In this study, we first exposed participants to an altered visualstimulationwhereoneobjectsystematicallychangeditsshapeduringsaccades.Subsequently,participantshad to judge the shape of briefly presented peripheral saccade targets. The results showed that targets were perceived as less curved for objects that previously changed from more circular in the periphery to more triangular in the fovea. Similarly,shapeswereperceivedasmorecurvedforobjectsthatpreviouslychangedfromtriangulartocircular.Thus, peripheral perception seems to depend not solely on the current input but also on memorized experiences, enabling predictions about the perceptual consequences of saccadic eye movements.

When circles become triangular: how transsaccadic predictions shape the perception of shape

What information can we extract from an initial glimpse of a scene and how do people differ in the way they process visual information? In Experiment 1, participants searched 3-D-rendered images of naturalistic scenes for embedded target objects through a gaze-contingent window. A briefly flashed scene preview (identical, background, objects, or control) preceded each search scene. We found that search performance varied as a function of the participants’ reported ability to distinguish between previews. Experiment 2 further investigated the source of individual differences using a whole-report task. Data were analysed following the “Theory of Visual Attention” approach, which allows the assessment of visual processing efficiency parameters. Results from both experiments indicate that during the first glimpse of a scene global processing of visual information predominates and that individual differences in initial scene processing and subsequent eye movement behaviour are based on individual differences i...

Werner X. Schneider

Papers

Parietal Damage Dissociates Saccade Planning from Presaccadic Perceptual Facilitation

The Subjective Direction of Gaze Shifts Long Before the Saccade

Influence of visuomotor action on visual-haptic simultaneous perception: A psychophysical study

When circles become triangular: how transsaccadic predictions shape the perception of shape

A glimpse is not a glimpse: Differential processing of flashed scene previews leads to differential target search benefits