Sections include: the neural basis of motivation and attention, history, looking for personality differences, disorders of attention and motivation, advice and intervention
Anyone who has lived with a pet has an intuitive sense that animals are devoid of the capacity for long-term, complex planning. Their behaviors are triggered by simple urges, like hunger and fear. By contrast, human behavior is not merely reactive; it is proactive. We formulate complex goals and intentions. This means that the human brain is capable of creating models of the world not only as it is but as we want it to be. The human brain is able to create models of the future. This is called intentionality. But merely creating a model of the future is not enough. We must have the ability to strive to change the world as it is into the world we want it to become. This ability is called motivation. Without motivation, no life challenge of any degree of complexity can successfully be met.
At any given time, the human brain performs numerous tasks simultaneously. At any given time, some of these tasks are more important than others. When circumstances change, cognitive priorities may change and different tasks become more important. Suppose you are watching TV while paying your bills. In all likelihood, your attention is on the bills (or at least it should be). Suppose then that the TV program is interrupted by a news announcement about an imminent tornado in your area, urging residents to take immediate precautions. Your attention will instantly be redirected to the news.
The ability to prioritize mental tasks, to focus on them, and to shift the focus to other tasks as the need arises is critical to the success of every human activity. This ability is called attention. Attention is a complex function, and we distinguish between sustained attention, distributed attention, and other forms. Without attention, our life would become haphazard and chaotic. Motivation and attention are among the most advanced manifestations of brain function, reaching their fully developed form only in humans.
The Neural Basis of Motivation and Attention
Motivation and attention are controlled by the prefrontal cortex, which is to the rest of the brain what a conductor is to the orchestra. The functions of the prefrontal cortex are elusive but critical and are often referred to as executive functions. Damage to the prefrontal cortex results in severe disruption of motivation and attention. Human behavior becomes purposeless, chaotic, and impoverished, despite the relative sparing of specific cognitive skills, such as reading, writing, or the use of simple tools. The famous case of Phineas Gage, whose prefrontal cortex was damaged in an explosion that drove an iron bar through his head, is a case in point—his friends were forced to conclude that “Gage was no longer Gage.”
The prefrontal cortex is the last part of the brain to mature. According to recent findings, it does not reach its functional maturity until the age of 18, or possibly even later. It has also been suggested that the prefrontal cortex is particularly vulnerable to the decline associated with aging. This suggests that the executive functions of the brain, while late to mature, are early to decline.
Neuropsychologists and neuroscientists have been studying the brain mechanisms of language, perception, and memory for many decades, but until recently attention and, particularly, motivation were regarded “off limits” for rigorous scientific exploration. The association of these complex mental functions with the prefrontal cortex was made only recently, within the last few decades. The advent of new technologies called functional neuroimaging, which enable us to examine patterns of physiological activity in the brain of a person engaged in a mental task, has been particularly important in advancing our understanding of the frontal lobes.
Looking for Personality Differences
Normal human brains are highly variable in morphology (overall brain size and the proportions of its parts) and biochemistry (the chemicals in charge of communications between the nerve cells). Neuropsychologists and cognitive neuroscientists are only beginning to study the biological basis of the normal variability of cognitive abilities and cognitive styles. The general public understands that differences among individuals in traits such as musical, literary, and mathematical abilities have something to do with the differences among human brains. But very few people seriously consider the possibility that differences in personalities (assertiveness as opposed to timidity, enthusiasm versus indifference, being a leader versus being a follower) are also related to differences among human brains. In fact, recent studies suggest that even such highly culture-dependent personality traits as morality depend on the integrity of the prefrontal cortex. An unusually high prevalence of frontal lobe damage or dysfunction has been documented in violent criminals and in people devoid of ethical insight (incapable of telling right from wrong in hypothetical situations). Certain types of patients with frontal lobe damage were referred to in the old neurological literature as pseudopsychopathic.
Disorders of Attention and Motivation
Attention and motivation may suffer in a wide range of disorders. Generally speaking, all these disorders involve damage to, or dysfunction of, the prefrontal cortex, certain structures particularly closely associated with the prefrontal cortex (for example, the anterior cingulate cortex, the neostriatum, the dorsomedial thalamic nucleus, and the ventral tegmental area of the mesencephalon), or their pathways. These conditions include traumatic brain injury, various dementias, schizophrenia, autism, Tourette’s syndrome, and others.
When the deficit of attention is relatively isolated, while other aspects of cognition are relatively intact, the diagnosis of attention deficit disorder, with or without hyperactivity, or ADHD, is often made. It is important to keep in mind, however, that ADHD is a syndrome and not a distinct disease, and it may be caused by a large number of specific disorders. It may be caused by traumatic brain injury or viral encephalopathy (disease of the brain), and is known to be associated with Tourette’s syndrome and other disorders.
When a previously highly motivated aging individual gradually loses his or her drive, the most common assumption is that the problem is depression. With the common emphasis on memory loss, the general public and even
many physicians and psychologists tend to overlook the fact that motivation and drive are among the first to suffer in most dementias, including Alzheimer’s-type dementia, cerebrovascular dementia, Lewy bodies dementia, Pick’s disease, frontal lobe dementia, and others. These conditions must always be considered whenever a decline in motivation and attention is noted in an aging person.
Changes in attention and motivation are also frequently observed in younger individuals recovering from the effects of traumatic brain injury suffered in, for example, a car accident or a job-related accident. These changes are often ignored or are attributed to something unrelated to the brain. But they are likely to be a direct consequence of the accident, since the prefrontal cortex and its pathways (particularly frontal connections with the brain stem) are particularly vulnerable in head trauma. The outcome of such injury is highly variable. Often considerable recovery takes place, sometimes even complete recovery, but in many cases long-term, or even permanent, impairment of attention and motivation takes place.
Advice and Intervention
Society has been slow to embrace the notion that diseases of the mind are diseases of the brain. It is still common for an individual whose mind is slipping, and for those around him witnessing cognitive impairment, to ignore this or to seek the help of everyone except a neurologist, psychiatrist, or neuropsychologist. Dysfunction of motivation or attention is particularly likely to be misattributed to some mysterious “extracerebral” factors, whatever they may be. The idea that persistent dysfunction of attention and motivation signifies brain disorder is still not well entrenched among the general public.
The situation is compounded by the fact that frontal lobe dysfunction, which affects motivation and attention, is also likely to produce lack of drive and inability to initiate behaviors, indifference, and anosognosia (lack of insight into one’s own condition). Therefore it is particularly important to sound the medical alarm whenever you observe such a change in a family member or a friend, since the patient is not likely to do it for himself or herself.
Ironically, when the general public does recognize disorders of the mind, the recognition is often overly simple. Every case of cognitive decline associated with aging becomes “Alzheimer’s disease,” and every case of neurodevelopmental cognitive dysfunction becomes “ADHD.” Even many professionals are guilty of this sin of sweeping oversimplification.
The bottom line is that deficits of attention and motivation may be caused by a wide range of neurological, psychiatric, neurodevelopmental, medical, and geriatric conditions. Careful, informed diagnosis is always better than a kneejerk invocation of the diagnosis du jour. Precise diagnosis is becoming particularly important with the advent of increasingly targeted therapies— pharmacological, cognitive-rehabilitative, and others.
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