- Slides: 18
Understanding brain development
Early brain development • The brain develops sequentially: • Brain stem • state regulation: pre-birth - 8 months • Mid-brain • motor functioning: first year • Limbic brain • emotional functioning: 6 months - 30 months • Cortex • cognitive functioning: 12 months - 48 months
Brain Architecture • The brain is made up of neurons, or brain cells, which connect to one another through synapses. • Synapses are physical gaps between neurons, like the gaps between the electrodes in spark plugs, through which nerve impulses travel. • The catch phrase in neuroscience is, “Cells that fire together, wire together”; or otherwise stated, “Use it or lose it. ”
Early Brain Development • We are born with most of the neurons we will ever own (around 100 billion) • At birth the brain is 25% of its adult weight by the age of 2 this has increased to 75% and by age 3 it is 90% of adult weight. • This growth is largely the result of the formation and ‘hard wiring’ of synaptic connections
What prevents normal brain development? • Intra-uterine problems: – Prenatal exposure to drugs and alcohol – Maternal stress • Attachment difficulties in the first years of life – – Parent or child chronic illness Parental capacity overwhelmed by practical or emotional demand Parental attachment or trauma history Lack of fit between parent and child • Neglect and trauma – Physical, emotional or stimulation needs not met – Abuse of the child – Witnessing violence
It is now accepted that a baby’s emotional environment will influence the neurobiology that is the basis of mind……. the most vital part is the emotional connection with the care giver.
• Babies’ brains are much more active and complex than previously believed. • We know that newborns can see at birth, particularly objects that are within a range of 12 inches or so. This is about the same distance between the baby’s eyes and a carer’s face when they are feeding them. • We also know that they can hear and can distinguish between a variety of sounds in the language spoken to them. • They are able to show preferences for the smell, sound, taste, appearance and feel of those people who are important to them.
The way the child is stimulated and soothed shapes the brain’s neurobiological structure. What happens in the early years has a direct impact on the child’s capacity for living, learning and relating as a social being
Impact of unregulated stress • All infants experience stress • Most infants are helped to manage this by those adults who love and care for them • If an infant’s experience is predominantly of neglect or fear then they will be in a state of unregulated stress. • The neuronal pathways that are most used are those associated with stress, alarm and fear. • Pathways that are associated with trust, soothing and pleasure remain undeveloped.
Early school years 5 -10 • Synaptic pathways that are regularly used are reinforced. This is the basis of learning. Reinforcement leads to permanent neurological pathways. • Neural connections needed for abstract reasoning are developed • Motor skills are refined • In sensory and motor brain areas the number of synaptic connections has reached mature levels by mid-childhood
Puberty –a second chance? Jay Giedd and colleagues have identified a second burst of proliferation of synaptic connections in the prefrontal cortex just before puberty. This is followed by pruning of these throughout the teenage years. This suggests that adolescence may be a time of both increased risk but also heightened opportunity, especially for those who have had particularly adverse experiences earlier in life.
The frontal lobe undergoes far more change during adolescence than at any other stage of life.
Brain regions and functions still developing in adolescence • Frontal lobe: self-control, judgment, emotional regulation; restructured in teen years • Corpus callosum: intelligence, consciousness and self-awareness; reaches full maturity in 20’s • Parietal lobes: integrate auditory, visual, and tactile signals; immature until age 16 • Temporal lobes: emotional maturity; still developing after age 16
What Happens In The Adolescent Brain? • Brain development continues up to at least the age of 20 • There is a significant remodelling of the brain in adolescence, particularly the frontal lobes and connections between these and the limbic system • Myelination – this is a process which insulates nerve fibres and enables neural pathways in the brain to become much more efficient at transmitting information. • Synaptic pruning in the prefrontal cortex. This is the area of the brain responsible for “executive functions” • Some changes are triggered by puberty, others by increased experience • The frequency and intensity of experiences shapes this remodelling as the brain adapts to the environment in which it is functioning and becomes more efficient
Emotional Functioning in Adolescence • Age of puberty has fallen by several years in the last century • Brain structures that are associated with emotional experiences change rapidly at the onset of puberty • The frontal brain structures that are associated with cognitive control mature much later than this • Some research suggests that there is a dip in children’s ability to judge social situations during early adolescence • Therefore there is a mismatch in development of the emotional and cognitive regulatory modes in adolescence • The combination of hormonal changes which increase risk taking and ignite passion, with a reduced capacity to make effective social judgments can be explosive.
What do the changes affect? • • • Emotions Motivation Self awareness Identity Empathy • • Risk taking Self control Perspective taking Judgement
Positive implications • Adolescent brains are still malleable and therefore potentially susceptible to learning new emotional, social, motor and cognitive patterns • Environmental factors may affect the nature of the synaptic pruning and therefore the development of preferred pathways. • It is not too late!
“teenagers are empowered with opportunities to develop their brains through the activities in which they choose to participate. ” ACT for Youth Factsheet Adolescent Brain Development 2002