The role of internal inhibition and the frontal lobes in child development

The theory that children show a predominance of excitation over internal inhibition and that this is due to inadequate development of the frontal lobes is explored and extended. Experimental results show that children resemble leucotomised monkeys in their difficulty in overcoming an initial preference in discrimination tasks.     

Strategy application disorder: the role of the frontal lobes in human multitasking

Strategy application disorder is a term used to describe a pattern of deficits, usually associated with frontal lobe dysfunction, where people show disorganisation, absentmindedness and problems with planning and decision making in everyday life despite normal performance on traditional neuropsychological tests. It is argued that the prototypical situation which presents problems for these cases are those which require multitasking, and although good cases are rare in the literature, those that do exist show a characteristic neuropsychological pattern. Moreover, this pattern is confirmed in recent group studies of multitasking and of the relationship between multitasking tests (such as the Six Element Test), failures in everyday life and other neuropsychological measures. At present the evidence suggests that the potential frontal brain regions most implicated in multitasking are the anterior cingulate; B.A. 10 and immediately adjacent areas; and the right dorsolateral prefrontal cortex, with each making a unique contribution to different aspects of performance. Furthermore, recent studies show striking dissociations between performances on multitasking tests and two of the most commonly administered measures of executive function: the verbal fluency test and the Wisconsin Card Sorting Test, which sets a minimum level for a fractionation of the executive syndrome in humans. Received: 31 March 1999 / Accepted: 23 July 1999     

The role of the inferior frontal junction area in cognitive control

Cognitive control processes refer to our ability to coordinate thoughts and actions in accordance with internal goals. In the fronto-lateral cortex such processes have been primarily related to mid-dorsolateral prefrontal cortex (mid-DLPFC). However, recent brain-imaging and meta-analytic studies suggest that a region located more posterior in the fronto-lateral cortex plays a pivotal role in cognitive control as well. This region has been termed the inferior frontal junction area and can be functionally and structurally distinguished from mid-DLPFC.     

The central role of the parietal lobes in consciousness.

There are now various approaches to understand where and how in the brain consciousness arises from neural activity, none of which is universally accepted. Difficulties among these approaches are reviewed, and a missing ingredient is proposed here to help adjudicate between them, that of "perspectivalness." In addition to a suitable temporal duration and information content of the relevant bound brain activity, this extra component is posited as being a further important ingredient for the creation of consciousness from neural activity. It guides the development of what is termed the "Central Representation," which is supposed to be present in all mammals and extended in humans to support self-consciousness as well as phenomenal consciousness. Experimental evidence and a theoretical framework for the existence of the central representation are presented, which relates the extra component to specific buffer working memory sites in the inferior parietal lobes, acting as attentional coordinators on the spatial maps making up the central representation. The article closes with a discussion of various open questions.     

The role of frontal lobe functioning in the development of infant self-regulatory behavior.

In the last two decades, there has been tremendous growth in two fields of study related to human infant development: (1) the development of neural processes during the early postnatal years and (2) the development of self-regulatory behavior. In an attempt to stimulate research on the relation between early brain development and self-regulatory processes, several hypotheses pertaining to the role of frontal lobe functioning in the development of emotion regulation during infancy are proposed. The results of a study of the relation between frontal electroencephalographic (EEG) activity and emotional behavior of 21-month-old infants are reported. It was found that increases in frontal lobe activation were associated with increases in emotional arousal, while EEG activity recorded from the parietal region showed either a reciprocal pattern of activation or did not change as a function of level of emotional arousal. These results provide evidence for the specialized role of the frontal lobe in mediating emotional behavior during infancy.     

The role of necessity in cognitive development

There seem to be two kinds of nonconservers—those who think their response might change on another occasion and those who think their response would always be the same. After training in conservation, the former (called nonconservers without necessity) show no detectable gains in conservation, while the latter (called nonconservers with necessity), surprisingly, show significant gains in conservation.In the present study, nonconservers with necessity were more likely than the nonconservers without necessity to think the classic conservation arguments (e.g., identity, negation, and compensation) were good and correct reasons and that the typical nonconservation reasons were poor and wrong.In sum, the nonconservers who can support their conclusions with the deductive force of necessity, even though they are wrong in their conclusion, appear to be more developmentally advanced than other nonconservers who do not offer necessity as part of the justification for their nonconservation conclusion.     

Executive control of gaze by the frontal lobes

Executive control requires controlling the initiation of movements, judging the consequences of actions, and adjusting performance accordingly. We have investigated the role of different areas in the frontal lobe in executive control expressed by macaque monkeys performing a saccade stop signal task. Certain neurons in the frontal eye field respond to visual stimuli, and others control the production of saccadic eye movements. Neurons in the supplementary eye field do not control directly the initiation of saccades but, instead, signal the production of errors, the anticipation and delivery of reinforcement, and the presence of response conflict. Neurons in the anterior cingulate cortex signal the production of errors and the anticipation and delivery of reinforcement, but not the presence of response conflict. Intracranial local field potentials in the anterior cingulate cortex of monkeys indicate that these medial frontal signals can contribute to event-related potentials related to performance monitoring. Electrical stimulation of the supplementary eye field improves performance in the task by elevating saccade latency. An interactive race model shows how interacting units produce behavior that can be described as the outcome of a race between independent processes and how conflict between gaze-holding and gaze-shifting neurons can be used to adjust performance.     

Aging effects on memory encoding in the frontal lobes

Functional magnetic resonance imaging (fMRI) was used to compare frontal-lobe activation in younger and older adults during encoding of words into memory. Participants made semantic or nonsemantic judgments about words. Younger adults exhibited greater activation for semantic relative to nonsemantic judgments in several regions, with the largest activation in the left inferior frontal gyrus. Older adults exhibited greater activation for semantic judgments in the same regions. but the extent of activation was reduced in left prefrontal regions. In older adults, there was a significant association between behavioral tests of declarative and working memory and extent of frontal activation. These results suggest that age-associated decreases in memory ability may be due to decreased frontal-lobe contributions to the initial encoding of experience.     

Information search following damage to the frontal lobes

Five adult patients with focal brain damage in different areas of the frontal lobes and five matched controls were administered a 20 Questions test. Other tests of planning, problem-solving, and decision-making were also administered to frontal lobe patients. The results indicate that damage to the frontal lobe impairs the ability to impose and utilize hierarchical organization in mental representation.     

Adaptive versus veridical decision making and the frontal lobes

Adaptive decision making and veridical decision making are based on different mechanisms. Veridical decision making is based on the identification of the correct response, which is intrinsic to the external situation and is actor-independent. Adaptive decision making is actor-centered and is guided by the actor's priorities. The prefrontal cortex is particularly critical for adaptive decision making and less so for veridical decision making. However, most experimental procedures used in cognitive psychology and neuropsychology focus on veridical decision making and ignore adaptive decision making. Innovative experimental procedures are required to characterize the contribution of the prefrontal cortex to adaptive decision making. We have designed a prototype for such procedures, the Cognitive Bias Task, and present the novel findings generated by this task.     

Executive functions and the frontal lobes: a conceptual view

Several problems in understanding executive functions and their relationships to the frontal lobes are discussed. Data are then presented from several of our studies to support the following statements: (1) the examination of patients with focal frontal lobe lesions is a necessary first step in defining the relation of executive functions to the frontal lobes; (2) there is no unitary executive function. Rather, distinct processes related to the frontal lobes can be differentiated which converge on a general concept of control functions; (3) a simple control-automatic distinction is inadequate to explain the complexity of control-automatic processes; (4) the distinction between complex and simple tasks cannot explain the differences in functions between the frontal lobes and other brain regions; and (5) the most important role of the frontal lobes may be for affective responsiveness, social and personality development, and self-awareness and unconsciousness. Received: 31 March 1999 / Accepted: 23 July 1999     

Emotion regulation in depression: Examining the role of cognitive processes

Sustained negative affect is a hallmark feature of depressive episodes. The ability to regulate emotional responses to negative events may therefore play a critical role in our understanding of this debilitating disorder. Individual differences in cognitive processes such as attention, memory, and interpretation may underlie difficulties in emotion regulation and numerous studies have identified cognitive biases and deficits that characterise depressed people. Few studies, however, have explicitly linked these biases to the difficulties in emotion regulation that are associated with depression. In this paper we discuss relations among cognitive processes and emotion regulation and review the depression literature to identify cognitive biases and deficits that may underlie maladaptive responses to negative events and mood states. Our review suggests that difficulties in the disengagement from negative material, memory biases, and deficits in cognitive control are frequently observed in depressive disorders and may be associated with the use of maladaptive emotion regulation strategies, such as rumination. These biases may also be related to difficulties implementing strategies that are effective for non-depressed people, such as recall of mood-incongruent material and reappraisal. Our review also suggests, however, that empirical studies linking cognitive biases and emotion regulation in depression are still largely missing and would present an important goal for future research in this area.     

A selective and critical review of neuropsychological deficits and the frontal lobes

Presumptions about the functions of the frontal lobes, and the sensitivity and specificity of certain tests to measure frontal lobe functions, are having a substantial influence on both clinical and research conclusions. In this paper the authors examine the details of the studies that have contributed to these presumptions, and find that the evidence to support these conclusions is weak. A detailed evaluation of the evidence relating to the Wisconsin Card Sorting Test and the Thurstone Word Fluency Test is also presented. Finally, the development of the belief that frontal lobe functions can be specifically measured is reviewed. The authors of this paper conclude that the bewildering array of deficits attributed to frontal lesions still seems to prevail.     

Distinguishing intentions from desires: Contributions of the frontal and parietal lobes

The ability to represent desires and intentions as two distinct mental states was investigated in patients with parietal (N = 8) and frontal (N = 6) lesions and in age-matched controls (N = 7). A task was used where the satisfaction of the desire and the fulfilment of the intention did not co-vary and were manipulated in a 2 × 2 set. In two experiments we show that lesions to the frontal lobe may impair the ability to deal with desires when their outcome is not congruent with that of the intention, and that parietal damage – especially if it encompasses the left temporo-parietal junction – may cause severe difficulties in the processing of both desires and intentions. The implications of the results for the neuropsychological and the developmental literature are discussed.