User:Aeroehri218/Developmental psychology

The 2nd (West Africa) Infantry Brigade

The infantry Brigade was a Second World War formation of the British Army. It was formed from battalions of the Royal West African Frontier Force in 1940. In the early part of the war, the Brigade served in the East African campaign before seeing action against the Japanese in Burma in 1944–45

Sleep
Many studies over the past several decades have explored the way in which sleep impacts development in prenatal and neonatal infants through early adolescents. While the exact function of sleep is still unknown, many researchers have examined the positive and negative influences that sleep can have on brain development.

REM
Infants begin showing distinct signs of sleep states at 28 weeks gestation, most of which is REM sleep. For the fetus and newborn baby, REM is a period of maximal brain activity. This is also a time period of rapid brain development. Because of the correlation between these two events, it is commonly believed that REM sleep contributes to the development of the brain.

The amount of daily time spent in REM sleep peaks at around 40 weeks from conception. For the first week of an infant's life, it spends nearly half of it's time sleeping and comparatively more time in a REM sleep state. After that point, average time in a REM state decreases. Because of the correlation to daily time spent in REM and the rapid brain development occurring in the infant, it is believed that REM influences development of the brain.

In a study done by Mirmiran, rats were deprived of REM sleep at this critical stage. Those that were not allowed to enter a REM cycle displayed higher rates of impotence, anxiety and depression later in life. Furthermore, the cerebral cortex and medulla oblongata were smaller in the deprived rats. This study suggests that lack of REM sleep at this critical period of development can prohibit the brain from growing in enriching environments.

One hypothesis is that the muscle twitching during REM is a way for the brain to fine-tune neural connections associated with motor learning. REM twitching may help prune synaptic connections to strengthen motor function.

Many believe that REM plays a strong role in memory consolidation and formation, but this belief is not universally held. While there are studies that seem to suggest sleep impacts memory, the topic is still wildly debated.

Memory
One study done with a group of toddlers suggested that sleeping helps form long-term memories. This study, which observed the toddler's brain activity through an EEG scan concluded that sleep allows toddlers to form episodic memories. Previously, it was not believed that toddlers could develop an episodic memory, so the findings of this study should be explored further.

Health and well-being
Sleep deprivation in infants and adolescents can lead to an increase in negative emotional expressions. Because newborn infants are often observed smiling during REM sleep, there is some suggestion that sleep may play a role in early emotional development. A separate study found that frequent disturbances to sleep were linked with a poorer outcome on the Bayley Scale of Infant and Toddler Development. Sleep-deprived toddlers comparatively struggle more with emotional regulation, and chronic deprivation can lead to anxious or withdrawn behaviors in a toddler. One longitudinal study observed that five year old's with consistently too little sleep ended up having more behavioral problems and poorer health at the age of nine.

Adolescents with Bipolar Disorder or Generalized Anxiety Disorder show more vulnerability to sleep disturbances. Inconsistent sleep schedules or lack of sleep can lead to depressive symptoms and higher anxiety, respectfully.