The unity and diversity of executive functions and their contributions to complex "Frontal Lobe" tasks: a latent variable analysis.

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

http://apsychoserver.psychofizz.psych.arizona.edu/JJBAReprints/PSYC501A/Readings/Polich_2007_Clin_Neurophys_Review_P3s.pdf

Updating P300: An Integrative Theory of P3a and P3b

When people encounter problems in translating their goals into action (e.g., failing to get started, becoming distracted, or falling into bad habits), they may strategically call on automatic processes in an attempt to secure goal attainment. This can be achieved by plans in the form of implementation intentions that link anticipated critical situations to goal-directed responses ("Whenever situation x arises, I will initiate the goal-directed response y!"). Implementation intentions delegate the control of goal-directed responses to anticipated situational cues, which (when actually encountered) elicit these responses automatically. A program of research demonstrates that implementation intentions further the attainment of goals, and it reveals the underlying processes.

/pdf/implementation-intentions-strong-effects-of-simple-plans-5a7euxxbxr.pdf

Implementation intentions: Strong effects of simple plans.

This article reviews a diverse set of proposals for dual processing in higher cognition within largely disconnected literatures in cognitive and social psychology. All these theories have in common the distinction between cognitive processes that are fast, automatic, and unconscious and those that are slow, deliberative, and conscious. A number of authors have recently suggested that there may be two architecturally (and evolutionarily) distinct cognitive systems underlying these dual-process accounts. However, it emerges that (a) there are multiple kinds of implicit processes described by different theorists and (b) not all of the proposed attributes of the two kinds of processing can be sensibly mapped on to two systems as currently conceived. It is suggested that while some dual-process theories are concerned with parallel competing processes involving explicit and implicit knowledge systems, others are concerned with the influence of preconscious processes that contextualize and shape deliberative reasoning and decision-making.

/pdf/dual-processing-accounts-of-reasoning-judgment-and-social-118hw7hde7.pdf

Dual-Processing Accounts of Reasoning, Judgment, and Social Cognition

One of the most challenging problems facing cognitive psychology and cognitive neuroscience is to explain how mental processes are voluntarily controlled, allowing the computational resources of the brain to be selected flexibly and deployed to achieve changing goals. The eighteenth of the celebrated international symposia on Attention and Performance focused on this problem, seeking to banish or at least deconstruct the "homunculus": that conveniently intelligent but opaque agent still lurking within many theories, under the guise of a central executive or supervisory attentional system assumed to direct processes that are not "automatic." The thirty-two contributions discuss evidence from psychological experiments with healthy and brain-damaged subjects, functional imaging, electrophysiology, and computational modeling. Four sections focus on specific forms of control: of visual attention, of perception-action coupling, of task-switching and dual-task performance, and of multistep tasks. The other three sections extend the interdisciplinary approach, with chapters on the neural substrate of control, studies of control disorders, and computational simulations. The progress achieved in fractionating, localizing, and modeling control functions, and in understanding the interaction between stimulus-driven and voluntary control, takes research on control in the mind/brain to a new level of sophistication.

Control of Cognitive Processes: Attention and Performance XVIII

Patients with extensive damage to the right hemisphere of their brain often exhibit unilateral neglect of the left side of space. The spatial attention of these patients is strongly biased towards the right1, so their awareness of visual events on the left is impaired2. Extensive right-hemisphere lesions also impair tonic alertness (the ability to maintain arousal)3, 4, 5. This nonspatial deficit in alertness is often considered to be a different problem from spatial neglect5,6, but the two impairments may be linked7,8. If so, then phasically increasing the patients' alertness should temporarily ameliorate their spatial bias in awareness. Here we provide evidence to support this theory. Right-hemisphere-neglect patients judged whether a visual event on the left preceded or followed a comparable event on the right. They became aware of left events half a second later than right events on average. This spatial imbalance in the time course of visual awareness was corrected when a warning sound alerted the patients phasically. Even a warning sound on the right accelerated the perception of left visual events in this way. Nonspatial phasic alerting can thus overcome disabling spatial biases in perceptual awareness after brain injury.

Letters to Nature: Phasic alerting of neglect patients overcomes their spatial deficit in visual awareness

The last decade has seen a resurgence of interest in the neural correlates of conscious vision, with most discussion focused on the 'blindsight' that can follow damage to primary visual cortex, in the occipital lobe. We suggest that new insights into the neural basis of visual awareness may be gleaned from a different neuropsychological phenomenon, namely visual 'neglect' after injury to regions in the parietal lobe. Neglect provides several revealing contrasts with occipital blindsight. Here we summarise four key findings. First, unlike the deficits caused by damage to primary visual cortex, the loss of awareness in parietal neglect is characteristically not strictly retinotopic. Second, visual segmentation processes are preserved in neglect, and can influence what will reach the patient's awareness. Third, extensive unconscious processing takes place for those stimuli on the neglected side which escape awareness, including some degree of object identification. Finally, parietal damage affects initial stages of motor planning as well as perception. These findings are consistent with recent data on single-cell activity in the monkey brain. They also suggest why areas in the inferior parietal lobe may play a prominent role in visual awareness.

/pdf/parietal-neglect-and-visual-awareness-2spc3u4spl.pdf

Parietal neglect and visual awareness.

Parietal neglect and visual awareness

The brain should integrate related but not unrelated information from different senses. Temporal patterning of inputs to different modalities may provide critical information about whether those inputs are related or not. We studied effects of temporal correspondence between auditory and visual streams on human brain activity with functional magnetic resonance imaging (fMRI). Streams of visual flashes with irregularly jittered, arrhythmic timing could appear on right or left, with or without a stream of auditory tones that coincided perfectly when present (highly unlikely by chance), were noncoincident with vision (different erratic, arrhythmic pattern with same temporal statistics), or an auditory stream appeared alone. fMRI revealed blood oxygenation level-dependent (BOLD) increases in multisensory superior temporal sulcus (mSTS), contralateral to a visual stream when coincident with an auditory stream, and BOLD decreases for noncoincidence relative to unisensory baselines. Contralateral primary visual cortex and auditory cortex were also affected by audiovisual temporal correspondence or noncorrespondence, as confirmed in individuals. Connectivity analyses indicated enhanced influence from mSTS on primary sensory areas, rather than vice versa, during audiovisual correspondence. Temporal correspondence between auditory and visual streams affects a network of both multisensory (mSTS) and sensory-specific areas in humans, including even primary visual and auditory cortex, with stronger responses for corresponding and thus related audiovisual inputs.

https://www.jneurosci.org/content/jneuro/27/42/11431.full.pdf

Jon Driver

Papers

Control of Cognitive Processes: Attention and Performance XVIII

Letters to Nature: Phasic alerting of neglect patients overcomes their spatial deficit in visual awareness

Parietal neglect and visual awareness.

Parietal neglect and visual awareness

Audiovisual temporal correspondence modulates human multisensory superior temporal sulcus plus primary sensory cortices.