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Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press Chapter.

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1 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press Chapter 12 Goals, Executive Control, and Action “He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires … A child in his intellectual capacity and manifestations, he has the animal passions of a strong man … His mind was radically changed, so decidedly that his friends and acquaintances said he was ‘no longer Gage’.” JM Harlow, Recovery from the passage of an iron bar through the head 1868/1998

2 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press Chapter Outline 1.0 Introduction 2.0 Phylogeny and ontogeny 3.0 Function overview 4.0 A closer look at frontal lobes 5.0 A closer look at frontal lobe function 6.0 Memories of the future 7.0 Novelty and routine 8.0 Ambiguity and actor-centered cognition 9.0 Working memory and working with memory 10.0 Theory of mind and intelligence 11.0 Frontal lobe pathology, executive impairment, and social implications of frontal lobe dysfunction 12.0 Executive control and social maturity 13.0 Towards a unified theory of executive control: a conclusion

3 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction From the silent lobes to the organ of civilization: it took scientists many years to begin to appreciate the importance of the frontal lobes for cognition. Unlike the busy sensory processes that occur in the other lobes, the frontal lobe were not easily linked to any single, easily defined function and were known as ‘the silent lobes’. The concept of executive control is intimately linked to the function of the frontal lobes, however not all functions of the frontal lobe fall under the domain of executive control, and not all executive control functions are subserved by the frontal lobes.

4 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction Prefrontal cortex can be divided into lateral (side), medial (midline), ventral (bottom), and dorsal (top) regions. The lateral division divides into dorsal and ventral halves separated by a major horizontal fold, the inferior lateral sulcus

5 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 2.0 Phylogeny and Ontogeny The prefrontal cortex has expanded over mammalian and primate evolution. A greatly enlarged prefrontal cortex is a distinctively human and primate feature. According to Brodmann (1909), the prefrontal cortex accounts for 29% of total cortex in humans, 17% in the chimp, 11.5% in the macaque, and 3.5% in the cat. While whales and dolphins have large brains, it is the parietal rather than frontal cortex that has expanded in these mammals.

6 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 Function Overview The functions of the frontal lobes defy a simple definition. They are not invested in any single ready-to-label function. Prefrontal cortex plays the central role in forming goals and objectives and then in devising a plan of action required to attain those goals. It selects the cognitive skills needed to implement the plans, coordinates those skills, and applies them in a correct order. Finally, the prefrontal cortex is responsible for evaluating our actions as success or failure relative to our intentions.

7 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 4.0 Closer Look at Frontal Lobes Gross anatomy and connections The prefrontal cortex is directly connected with every distinct functional unit of the brain. A schematic of prefrontal connectivity: the prefrontal lobes (inside the yellow box) have prolific connections throughout cortical and subcortical regions.

8 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 4.0 Closer Look at Frontal Lobes The massive connectivity of the frontal lobes is suggested by this tractograph (right panel) of the fiber tracts to Brodmann area 10 (left panel). The red and dark vertical fibers show only the ipsilateral (same hemisphere) connections.. In addition to these fiber tracts, there are many connections between the two hemispheres traveling across the corpus callosum.

9 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 4.0 Closer Look at Frontal Lobes How prefrontal cortex is defined A precise definition of prefrontal cortex can be accomplished using Brodmann area maps -- which are based on the types of neurons and connections that are typically found within each area. The prefrontal cortex is comprised of Brodmann areas 8, 9, 10, 11, 12, 13, 44, 45, 46, and 47. A lateral view of the prefrontal cortex, showing Brodmann areas 8, 9, 10, 11, 44, 45, 46, and 47.

10 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 4.0 Closer Look at Frontal Lobes How prefrontal cortex is defined A precise definition of prefrontal cortex can be accomplished using Brodmann area maps -- which are based on the types of neurons and connections that are typically found within each area. The prefrontal cortex is comprised of Brodmann areas 8, 9, 10, 11, 12, 13, 44, 45, 46, and 47. A mid-sagittal view of the prefrontal cortex, showing Brodmann areas 8, 9, 10, 11, and 12.

11 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 4.0 Closer Look at Frontal Lobes How prefrontal cortex is defined Another method of outlining the prefrontal cortex is through its subcortical projections. The dorsomedial thalamic nucleus is a point of convergence, the ‘summit’ of the integration occurring within the specific thalamic nuclei.

12 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 5.0 A Closer Look at Frontal Lobe Function Traditional perspective on frontal lobe function: motor functions, actions, and plans Two broad types of cognitive operations linked to the frontal lobe executive system: 1. An organism’s ability to guide its behavior by internal representations -- the formulation of plans and then guiding behavior according to those plans

13 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 5.0 A Closer Look at Frontal Lobe Function Traditional perspective on frontal lobe function: motor functions, actions, and plans Two broad types of cognitive operations linked to the frontal lobe executive system: 2. An organism’s ability not only to guide its behavior by internal representations, but also the capacity of ‘switching gears’ when something unexpected happens

14 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 5.0 A Closer Look at Frontal Lobe Function Mental Flexibility To deal effectively in situations that call for ‘switching gears’ requires mental flexibility -- the capacity to respond rapidly to unanticipated environmental contingencies. A task used to assess mental flexibility: the subject must extract the ‘rules’ in order to place the round object in the proper location.

15 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 5.0 A Closer Look at Frontal Lobe Function The subject is instructed to place the object in one location (top panel), however he is told that the rule may change at any time during the task. In the first trial, the object is correctly placed and the subject is given feedback that this is correct. The subject repeats that placement in the second trial and again receives feedback that it is correct. In the third trial (bottom panel), the rule has changed and the object must now be placed in the other location. Patients with frontal lobe damage have difficulty in ‘switching gears’ in this type of task.

16 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 6.0 Memories of the Future Ingvar (1985) coined the phrase ‘memories of the future‘ referring to one of the most important functions of advanced organisms: making plans and then following the plans to guide behavior. Unlike primitive organisms, humans are active, rather than reactive, beings. We are able to form goals, our visions of the future. Then we act according to our goals. In order to guide our behavior in a sustained fashion, these mental images of the future must become the content of our memory: thus the ‘memories of the future’ are formed.

17 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 7.0 Novelty and Routine Another function currently being linked to the prefrontal cortex is an ability to deal with cognitive novelty. The dark areas in this composite brain image show regions that control novel actions, but which lose activity when the identical actions becomes automatic with practice.

18 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 8.0 Ambiguity and Actor-Centered Cognition In our everyday life, we encounter two types of situations: Deterministic: situations like balancing a checkbook, remembering a phone number, or someone’s name are deterministic. There is a single correct solution intrinsic to the situation. By finding the correct solution, we engage in veridical decision-making. Ambiguous: situations like deciding what to wear, which movie to see, or which career path to take are ambiguous. They do not have an intrinsically correct solution. By making our choice, we engage in adaptive (or actor-centered) decision making.

19 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 8.0 Ambiguity and Actor-Centered Cognition The Cognitive Bias Task Most decision-making in life entails adaptive decision-making where there is no single correct answer. The prefrontal cortex is central to such decision-making processes. The Cognitive Bias Task (CBT) was developed by Goldberg and colleagues. It provides a sensitive way to assess adaptive decision-making strategies in frontal lobe patients.

20 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 8.0 Ambiguity and Actor-Centered Cognition The Cognitive Bias Task The task is simple: the patient sees the top part of the card (‘target’, a solid red square) and then must quickly select one of the two lower figures (two open red circles or solid blue square). The patient is told that there are no ‘right’ answers. A similarity index is prepared for each patient based upon the dimensions of similarity between the target and the two choices: color, shape, size, etc.

21 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 8.0 Ambiguity and Actor-Centered Cognition The Cognitive Bias Task The similarity index will shed light on how context- sensitive the subject is when making a complex decision. For example, the solid blue square is similar to the solid red square in size, fill-pattern, and shape thus if it was selected it might show a higher level of context- sensitivity then selecting the card with the two open red circles that share only color with the target.

22 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 9.0 Working Memory and Working with Memory Working memory is closely linked to the critical role the frontal lobes play in the temporal organization of behavior and controlling the proper sequence in which various mental operations are enacted. Since the selection of information required to solve the problem at hand is made in the frontal lobes, they must ‘know’, at least roughly, where in the brain the information is stored. This suggests that all the cortical regions are somehow represented in the frontal lobes, an assertion first made by Hughlings-Jackson in 1884.

23 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 10.0 Theory of Mind and Intelligence Planning and organizing mental operations in order to obtain our goals are critical frontal lobe functions, however we frequently must take into account others’ plans and goals for their actions. To succeed in this interaction with others, you must not only be able to have an action plan of your own, you also have an insight into the nature of the other fellow’s plan.

24 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 10.0 Theory of Mind and Intelligence To do that, you must have the capacity to form an internal representation of the other person’s mental life -- or as it is called in cognitive psychology, to have a theory of mind. Your actions will be chosen under the influence of your theory of the other person’s mind formulated in your own mind. This makes the executive processes required for success in an interactive environment much more complex than those required in a solitary situation.

25 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction The fragile frontal lobes Frontal lobe dysfunction often reflects more than the direct damage to the frontal lobes themselves. The frontal lobes seem to be the bottleneck, the point of convergence of the effects of damage virtually anywhere in the brain. There is a reciprocal relationship between frontal and other brain injuries: damage to the frontal lobes produces wide ripple effects through the whole brain.

26 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Frontal lobe syndromes Damage to different parts of the frontal lobes produces distinct, clinically different syndromes. The most common are dorsolateral and orbitofrontal syndromes.

27 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Frontal lobe syndromes - Dorsolateral Most common symptoms of dorsolateral syndrome are perseverative behavior, field- dependent behavior, and mental rigidity. These patients often typically have a flat affect: an emotionless voice and facial expression. Perseverative behavior: a patient will have an inability to initiate behaviors. Once behaviors are initiated, the patient is equally unable to terminate or change the behavior.

28 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Frontal lobe syndromes - Dorsolateral Field-dependent behavior highlights the distractibility seen with frontal lobe injury. A patient will drink from an empty cup, put on a jacket belonging to someone else, or scribble with a pencil on the table surface, merely because the cup, jacket, and pencil are there, even though these actions make no sense.

29 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Frontal lobe syndromes - Dorsolateral Mental rigidity is a frequent symptom of frontal lobe injury. Mental flexibility is a critical aspect of frontal lobe processing. These patients will show an inability to change their mental state or approach to a problem. The Wisconsin Card Sorting task is frequently used to asses mental rigidity in frontal lobe patients.

30 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Frontal lobe syndromes - Orbitofrontal The orbitofrontal syndrome is in many ways the opposite of dorsolateral syndrome: the patients are behaviorally and emotionally disinhibited. Their affect is rarely neutral, constantly oscillating between euphoria and rage, with impulse control ranging from poor to non-existent. Their ability to inhibit the urge for instant gratification is severely impaired: they do what they feel like doing, when they feel like doing it, without any concern for social taboos or legal prohibitions.

31 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Other clinical conditions associated with frontal lobe damage It is not necessary to have focal damage to the frontal lobes themselves to have prefrontal dysfunction. The frontal lobes are particularly vulnerable in numerous non-focal disorders such as schizophrenia, Tourette’s syndrome, and Attention deficit (hyperactivity) disorder (AD(H)D).

32 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 11.0 Frontal Lobe Pathology, Executive Impairment, and Social Implications of Frontal Lobe Dysfunction Other clinical conditions associated with frontal lobe damage Attentional functions might may be influenced bu the frontal lobes as well as an ‘attentional loop’ combining frontal, brainstem, and posterior cortex. Breakdown anywhere along this loop may interfere with attention, thus producing a form of attention deficit disorder. Thus, any damage to the prefrontal cortex or its pathways may result in attentional impairment.

33 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 12.0 Executive Control and Social Maturity The capacity for volitional control over one’s actions is not innate, but it emerges gradually through development. It is an important, perhaps central, ingredient of social maturity. Early mother-infant interaction is important for the development of the orbitofrontal cortex during the first months of life.

34 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 12.0 Executive Control and Social Maturity The orbitofrontal cortex is not the only part of the frontal lobes linked to socially mature behaviors: the anterior cingulate cortex (ACC) is closely linked to the prefrontal cortex and has been linked to emotion and regulation of distress. The ACC has been shown to more active in depressed subjects, however it is not know whether this is due to the direct effects of negative mood or indirect conflict signals related to depression.

35 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 12.0 Executive Control and Social Maturity The ACC appears to be active during situations of social rejection: in a task designed to evoke the sense of social rejection (as felt by a child in a ball game), the frontal part of the cingulate ‘lights up’.

36 Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 13.0 Towards a Unified Theory of Executive Control: A Conclusion After having been overlooked for many decades, executive functions have become the focus of an ever-increasing body of research. A Modular View: one approach has been to ‘fractionate’ executive functions along the familiar lines of sensory modalities (vision vs. audition), linguistic versus non- linguistic, object versus spatial (‘what’ versus ‘where’) distinctions. A Gradient View: a different approach suggests that the functional organization of heteromodal association cortices (such as prefrontal cortex) is interactive and distributed, and not modular. Which approach is the correct one? Only time and future research will tell!


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