Prefrontal Cortex - Our Moral Monitor

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Is The Prefrontal Cortex Our Moral Monitor?

The Prefrontal System, or prefrontal cortex, is one of the largest critical subregions in the human brain. Brodmann estimated that it constitutes 29% of the cortex in human beings, as compared to 17% chimpanzees, 7% in dogs, and 3.5% in cats.

Its high degree of development in human beings suggests that it too may mediate a variaty of specifically human functions, often referred to as "executive functions" such as abstract thought, creative problem solving, and temporal sequencing of behavior.

The lesion method provided an early landmark in our understanding of the prefrontal cortex through the case of Phineas Gage, a quarry worker who was injured by explosion that drove an iron bar through his left frontal lobe. Gage survived the bizarre accident, but afterward he began to show serious personality changes that were described by Harlow (the physician who cared for him and saved his life).

Prior to the accident Gage was conscientious, serious, and hardworking, but after recovered he became immature, child-like, socially inappropiate, and irresponsible. Harlow's early descriptions of frontal lobe functions has been supplemented by many subsequent studies of people with frontal tumors, injuries to the frontal lobe, and surgical treatment for epilepsy, psychosis or obsessive-compulsive disorder. This work indicates that substantial damage to the prefrontal cortex produces a syndrome quite similar to that of Gage.

Although general intelligence is not necessarily impaired by frontal lesions, individuals with substantial frontal injury the other capacities such as volitions, the ability to plan, and social judgment.

Two different subtypes of "frontal syndromes" have been observed:

Lesions to the orbital region of the prefrontal cortex (a more "primitive" part of the frontal cortex on its lower surface, just above the eyes) make people euphoric, overactive, and inclined to inappropriate social behavior such as sexual overtures to unknown people.

Lesions to the dorsolateral portion (the outer convexities of the frontal lobes on the side of the brain) make people apathetic, physically inactive, and less able to perform complex cognitive tasks such as formulating an abstract concept.

Within both of these syndromes, however, lies a common core: impairment in the capacity to pursue goal-directed behavior, based in the integration of environmental and internal cues. This is probably the basic functions of the prefrontal cortex.

The prefrontal cortex matures particularly late in human beings, concluding its development in the third decade of an individual’s development. (which partly explains the behavior of "typically adolescent" angry, insecure and confused).

"BRAVE NEW BRAIN", Conquering Mental Illness in the Era of the Genome, Nancy C. Andreasen, 2000, pages 68 - 69

The Sleep and the Child Development

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The Sleep and the Development of the Brain Child

Early school starting time has been associated with increased sleep deprivation and daytime sleepiness and poorer school performance (Carskadon et al., 1998). The children involved complain significantly more about being tired throughout the day and having attention and concentration difficulties than those with a later school start time (Epstein, Chillag and Lavie, 1998). It remains debatable whether school start times are too early: more studies would be needed before any firm conclusions could be made about their effects, together with experiments to better understand the relationship between sleep and learning (such as memory consolidation).

The effectiveness of school lessons, workplace training sessions or conferences could increase if their scheduling and planning took account of the scientific findings on sleep. Educators might, for example, schedule lessons for adolescents later in the day and advise students on the benefits of recapping lessons after a night’s sleep.


Parents could play a valuable role in helping to nurture their children’s brains by ensuring that they get enough sleep and, before bedtime, avoiding activities that hype up the brain, such as computer games.

“How Much is Enough?”

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“How Much is Enough?”

Any discussion of deprived or reduced sleep raises the question “how much is enough?”. Because individual differences in sleep requirements are large, it is impossible to give simple guidelines that would suit every person.

There is also evidence that having a nap after learning a task appears to improve performance so that the common expression “let’s sleep on it” is not an example of a proverbial "neuromyth". Robert Stickgold (2003) performed studies on a group of students at Harvard University, showing that performance on a complex task requiring a great deal of attention and concentration could be restored to the levels observed early in the experiment by subjects taking a nap of between 30-60 minutes.

As sleep deprivation appears to be prevalent among children, more studies to screen for sleep disturbances and more experimental studies would help to ascertain their association with psychological symptoms and diminished cognitive performance.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 74

Comnent (Aditional Information)

Sleep and your Age

When we are born we need up approximately to 18 hours of sleep each day. Much of this spent in REM sleep, which is thought contribute to brain development. As REM is often followed by a period of lighter sleep or waking, you can see why babies sleep for a short period then wake.

The amount of sleep needed decreases as a child grows up. Three to five –year-olds need around 11-13 hours of sleep during the night as most have given up napping during the day by then. By age of five or so, only a little over two hour are spent in REM sleep. Pre-teens may need between nine and eleven hours of sleep, while teenagers need to ten hours on average.

As we age, the need for sleep alters, and around half older people complain of regular sleep problems. Older people may not need less sleep but may find themselves spending less of the night in deep sleep. Hormone levels change often leaving older people struggling to get to sleep; waking early and then needing to nap during the day.

Poor health or less active lifestyle can also reduce the ability to sleep for solid seven or eight hours.

Women are more likely experience insomnia than men. Insomnia affects between 15% and 30% of men, and 25% to 40% of women.

"IMSOMIA", The Essential Guide, Antonia Chitty & Victoria Dawson, 2009, page 8

Take Care of your Children's Sleep

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Take Care of your Children's Sleep

An early study showed that one night’s complete sleep loss had similar effects in children aged 11-14 years to those previously shown in adults (Carskadon, Harvey and Dement, 1981). Partial sleep restriction was found to lead to some impaired cognitive functions. Routine performance, on the other hand, was maintained even after one full night’s sleep restriction (Randazzo et al., 1998). Shorter sleep duration has been demonstrated to lead to poorer performance on short-term memory tasks (Steenari et al., 2003).

In recent years, an increasing number of studies have reported associations between children’s sleep disturbances and various psychological symptoms, including depression and behavioural problems (Morrison, McGee and Stanton, 1992; Chervin et al., 1997; Dagan et al. 1997; Corkum, Tannock and Moldofsky, 1998; Dahl, 1998; Marcotte et al., 1998; Aronen et al., 2000; Smedje, Broman and Hetta, 2001).

Attention Deficit Hyperactivity Disorder (ADHD) is a neuropsychological disorder in which sleep disturbance frequently occurs. Several studies have reported increased rates of sleep problems among children with ADHD (Chervin et al., 1997; Marcotte et al., 1998; Stein, 1999; Owens et al., 2000a). Children with ADHD, compared with the control children, have higher parent-reported bedtime resistance, sleep-onset problems, sleep-related anxiety, daytime sleepiness, parasomnias and shorter sleep duration (Owens et al., 2000b).



Certain environmental factors have also been shown to be related to sleep disturbances. For example, high quantities of televisionviewing, particularly at bedtime, have adverse effects on sleep (Owens et al., 2000a). Moreover bedtime resistance (Blader et al., 1997; Smedje, Broman and Hetta, 1998) as well as sleeping in the same bed as parents have been correlated with sleep-onset problems (Lozoff, Wolf and Davis, 1984; Madansky and Edelbrock, 1990; Latz, Wolf and Lozoff, 1999).

"Understanding the Brain", The Birth of a Learning Science, 2007, page 74

The Sleep Disturbances and the Learning

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The Sleep Disturbances and the Learning

Children’s sleep disturbances have been linked with numerous somatic disorders, neurological illnesses and emotional and behavioural disturbances such as hyperactivity, as well as learning difficulties (Ferber and Kryger, 1995).

Sleep disturbances are highly prevalent and persistent and are among the most common complaints throughout childhood: epidemiological studies have shown that approximately one third of all children suffer from sleep problems (Simonds and Parraga, 1984; Kahn et al., 1989; Blader et al., 1997; Rona, Gulliford and Chinn, 1998). A survey of clinical paediatricians suggested that they are the fifth leading concern of parents (following illness, feeding, behavioural problems and physical abnormalities; Mindell et al., 1994).

Although there are common sleeping disorders at all ages (Wiggs and Stores, 2001), there are also age-specific patterns as with the changes which happen during adolescence. A questionnaire-based survey of sleeping habits of 25 000 people between ages 10-90 shows that children are typically early risers, but start to sleep progressively later as they enter adolescence, reaching a maximum lateness around the age of 20, when the curve starts to decline (Abbott, 2005).

Generally, individuals have increased daytime sleepiness at puberty, whether or not there are changes in total sleep duration, suggesting that the biological need for sleep does not diminish during adolescence (Carskadon et al., 1980).

Some studies tentatively suggest that sleep deprivation and sleeping problems are associated with poorer academic performance: the less they sleep, the lower their performance (Wolfson and Carskadon, 1998).

Since many children suffer from chronic sleep deprivation there is a very real concern about the potentially harmful effects that this has for the developing brain. While experimental sleep deprivation studies on children are rare for ethical reasons, those carried out have investigated cognitive consequences of sleep deprivation.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 74

The Sleeping and Learning

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The Sleeping and Learning

Approaches involving human functional imaging (the recording of activity from larger neuronal networks) and genetic or pharmacological manipulation of the brain have converged to support the notion that the stages of sleep (slow wave sleep and REM sleep) function in concert to reprocess recent memory traces and consolidate memory, and this across different species and different learning tasks (Stickgold, 2003).

Whereas REM sleep seems to benefit particularly the consolidation of skill memories, slow wave sleep enhances particularly the consolidation of explicit declarative memories depending on the hippocampus. Numerous sleep deprivation studies support the idea that sleep contributes to the stabilisation of acquired memory.

Evidence from experiments in animals and humans support the concept of an “offline” reprocessing of recent experiences during sleep that is causative for memory consolidation (Ji and Wilson, 2007; Rasch et al., 2007), and analysis of the thalamocortical system establishes the reciprocal observation that sleep is itself a plastic process affected by waking experience (Miyamoto and Hensch, 2003).

One hypothesis is that sleep plays a key role in neural plasticity, i.e. in maintaining appropriate connections between neurons through reinforcing significant connections between synapses and eliminating accidental ones. It has been proposed that the entire cortex experiences neural plasticity in sleep, as it “updates” following experiences of the world, especially the previous day’s events (Kavanau, 1997).

"Understanding the Brain", The Birth of a Learning Science, 2007, page 74

The Sleep and the Health

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The Sleep and the Mental Health

The function of sleep has always fascinated scientists, while remaining something of a biological mystery. Fundamental questions about it remain to be clarified. From a neurophysiological point of view, it is a specific state of brain alertness.

Brain studies are not necessary for us to know that adequate sleep is necessary in order for people to remain alert and awake: clearly, the functions of sleep are essential to life. Researchers are unanimous that while many bodily functions can recover during wakefulness, only sleep can restore cortical functions (Horne, 2000).

Sleep quality is closely related to well-being, poor sleep can also have a negative impact on mood (Poelstra, 1984) and behaviour (Dahl and Puig-Antich, 1990). Latent sleep disorders can in some cases result in psychological symptoms (Reite, 1998). In adults, daytime sleepiness is related to impairments in work and social life, increased disorders, and increases risks such as of motor vehicle accidents (Ohayon et al., 1997).

Studies, from the behavioural to the molecular level, suggest that sleep contributes to memory formation in humans and other mammals (Maquet, 2001). Sleep was first implicated in learning and neural plasticity with studies performed on animals, which showed a correlation between the amount of rapid eye movement (REM) sleep and performance on a learned task (Smith, 1996).

Recent studies in humans provided evidence for a critical involvement of slow wave sleep and associated slow EEG oscillations in the consolidation of memories and underlying neural plasticity (Huber et al., 2004, Marshall et al., 2006).

"Understanding the Brain: The Birth of a Learning Science", 2007, page 73

Social Interactions and the Brain

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Social Interactions and the Brain

There are social influences on the brain which have a direct impact on its ability to function optimally for learning. The importance of positive social influences on physiology and behaviour has been established.

In the past two decades, infants have been increasingly recognised as seekers and providers of social interaction and communication. Even though much of early learning appears to be automatic, it requires a naturally rich and stimulating environment in which social interaction is very important (Blakemore, Winston and Frith, 2004).

A study of Romanian orphanages has shown that a lack of emotional nourishment can lead to attachment disorder (O’Connor, Bredenkamp and Rutter, 1999).

Another study of children reared in an extreme social environment in which they were deprived of any of the normal care found that such deprivation can produce relatively permanent changes in a child’s brain chemistry, impairing the production of hormones such as oxytocin that are integral to bonding and social interaction.

These findings support the view that there is a crucial role for early social experience in the development of the brain systems underlying key aspects of human social behaviour (Fries et al., 2005).

"Understanding the Brain: The Birth of a Learning Science", 2007, page 62

The Importance of Omega-3 Fatty Acids

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The Importance of Omega-3 Fatty Acids

It is thus essential to take account of these nutritional needs throughout the day and to distribute nutritional intake to take account of these needs. Beyond this, 39 vital elements are not produced by the body and therefore need to be obtained from a dietary source (OECD, 2003b).

A recent finding has confirmed the benefits of the old-fashioned bane of children’s daily diet – the spoonful of cod liver oil. This staple “potion”, like other fish oils, is particularly rich in highly unsaturated fatty acids (HUFA), now commonly referred to as omega-3 fatty acids. They are particularly important for hormone balance and the immune system both of which are crucial for a healthy brain. In many modern diets, fatty acids have become relatively scarce, yet they are still essential to normal brain development and function.

While it is necessary not to be swept along by faddish enthusiasm for omega-3 fatty acids before more extensive brain studies have provided evidence for such claims, a randomised controlled trial of dietary supplementation with omega-3 and omega-6 fatty acids versus a placebo was conducted on 117 children aged 5-12 years with Developmental Dyspraxia, also known as Developmental Co-ordination Disorder (DCD). Results showed that while no effect of the active treatment on motor skills was apparent, significant improvements were found in reading, spelling and behaviour over 3 months of treatment in parallel groups. The conclusion reached was that fatty acid supplementation may offer a safe and efficient treatment option for educational and behavioural problems in children with DCD (Richardson and Montgomery, 2005).

Another study was undertaken in prisons in the United Kingdom to test whether adequate intakes of vitamins, minerals and essential fatty acids caused a reduction in antisocial behaviour, including violence. This was indeed the case and is particularly relevant for those with poor diets (Gesch et al., 2002).

Although scientific evidence shows that a diet rich in essential fatty acids and eating a good breakfast contribute to good health and improved learning, the clear, messages from this research have, to date, not been widely taken on board by policy to ensure its practical application. It is thus necessary to expand studies and apply such findings to the education domain.

Promoting healthy behaviour among students should be a fundamental mission of schools: providing young people with the knowledge and skills they need to become healthy and productive adults. This will improve their capacity to learn; reduce absenteeism; and improve physical fitness and mental alertness. School administrators, school board members, teachers, social workers and parents should be encouraged to seek information and resources on the importance of nutrition for children’s health and their academic performance.

Understanding the Brain: The Birth of a Learning Science", 2007, page 61