Cognitive Development in Children Ms. Carmelitano

Brain Review: 4 Lobes Frontal Lobe- Parietal Lobe- Occipital Lobe- reasoning, planning, parts of speech, movement, emotions, impulse control and problem solving Parietal Lobe- movement, orientation, recognition, perception of stimuli Occipital Lobe- visual processing Temporal Lobe- perception and recognition of auditory stimuli, memory, and speech

Brain Review Dendrite: the threadlike extensions of a neuron; They are the receptive site of the neuron and branch out to make connections with the dendrites of other neurons Dendritic Branching: When a neuron grows more dendrites, creating increased connections between nerve endings This allows for tasks to become easier, and more efficiently completed

Natural Reflexes At birth a baby has natural reflexes such as: Sucking Grasping Basic visual and auditory abilities They are prepared for social interaction Babies respond to human faces from birth Babies exchange sounds and non-verbal signals with their primary caregiver This may be due to mirror neurons

Brains of newborns There are more than a trillion nerve cells working in the brains of infants They are supported by a trillion glial cells: 90% of the cells in the human body (These are cells which support neuron function) Synaptic growth in the brain is more significant in the first year of life than any other time in person’s life However, brain development will continue until late adulthood This is called neuroplasticity: the ability of the brain to develop and change in response to the environment Brain activity increases with synaptic growth Why do you think synaptic growth is so rapid in the early stages of life?

Pet Scan A positron emission tomography (PET) scan is an imaging test that helps reveal how your tissues and organs are functioning. A PET scan uses a radioactive drug (tracer) to show this activity.

Chugani 1999 Modern technology can study brain development Procedure: Performed a PET scan of glucose metabolism in the brains of newborn human babies Found: Little activity in the cerebral cortex: associated with high level functioning There is high activity in the brain stem and thalamus, associated with inborn reflexes The limbic system, amygdala, hippocampus, and cingulate cortex (associated with memory, emotional processing, and bonding) are somewhat active Conclusion: This supports the reason why babies have a high capacity to observe and read emotional content of human faces and to communicate with facial expressions But they do not have the same abilities to think and plan

Bachevalier 1999 Lesioned the highly active areas of the brain, Chugani discovered, in new born monkeys The monkeys gradually lost the capacity for social behavior Eye contact decreased, and the animal showed blank facial expressions This is also found in children who are autistic The conclusion of observations like these is that reading facial expressions is to some extent an innate capacity which can be lost due to brain damage

Brain Development From age 6-9 months the frontal and prefrontal areas of the cortex begin to function more fully due to the growth and myelination of neurons (the formation of the myelin sheath – which enables nerve cells to transmit information faster and allows for more complex brain processes) The hippocampus will also develop during this time This plays a role in memory The cerebellum will develop which controls body movements This will increase the ability for more complex motor behavior and increase the ability to learn Chugani shows a steady increase in glucose metabolism in these areas, that will continue until age one Glucose metabolism will increase and reach adult levels around the second year of life

Pruning Pruning is the process of weeding out unnecessary neural connections and strengthening the important ones, based on the child's experiences. The most rapid pruning happens between about age 3 and age 16 Different areas of the brain undergo pruning during different sensitive periods Experiences during infancy and childhood form the connections that shape the development of the brain. Pruning is a key part of brain development because it eliminates the connections that are not used often enough. Pruning provides room for the most important networks of connections to grow and expand, making the brain more efficient. They create unique connections for each individual depending on the environment in which they live

Memory, Attention, and the brain Gelman 2003 Argues that by the age of 2, children have the ability to understand new, non-obvious features of things Because of this, they will be more likely to pay attention to objects with bright colors, or “different,” “fun,” noises

Memory, attention, and the brain Bauer and Pathmann 2008 The weight of the brain increases from 25% of its adult weight at birth, to 75% of its adult weight by 2 years old The hippocampus forms prenatally However the dentate gyrus, which links the regions of the brain, will not be fully developed until 12- 15 months old and the pre-frontal cortex will not be fully formed until 2 years old Result: Infantile amnesia – Children have the ability of conscious memory at birth, but cannot recall explicit memories until age 3 This is why you have few – if any – memories of your life before your third birthday Pres-school brains fade faster than older brains when it comes to explicit memories Stein 1995 Children under the age of three have the ability to retain and later recall implicit memories, because the amygdala forms earlier than the hippocampus. Memories for doing implicit tasks will also develop sooner This is why a baby can “remember” how to balance and walk, but may not remember their mother’s birthday. Howe 1995: Memory requires storage and retrieval. Children from ages 1 to 11 have problems in storage. The average 3 year old can repeat two digits in succession and at age 7 can repeat four.

The Brain during adolescence When children become teenagers, they begin to develop the ability to think in more abstract ways Brain changes are less dramatic than in earlier life, but still are important Reorganization and myelination of the higher brain centers, like pre-frontal cortex continue until age 20 This is why people become better able to strategically plan as they get older Impulse control in the prefrontal cortex is the last to mature around 20 years old – Giedd 2004

Giedd 2004 Longitudinal study Gave MRI to children every 2 years Found: 95% of the brain structure is formed when children are 5 or 6 Areas in the prefrontal cortex appear to grow again just before puberty Conclusion: Different parts of the brain mature at different times