Lecture 12: Brain Development

What happens to the brain by 9th month of development?

The cortex is wrinkled, recognizable as human and structures under the cortex are in working order

What is the process where the brain gets rid of extra or unused connections?

Synaptic pruning

What is neuronal maturation after birth?

Neurons begin to extend their axons and connect to other neurons

What are the principals on brain development?

1. Specialization is evident early in development

2. Specialization takes on two forms

3. Different brain systems specialize at different rates

4. Successful specialization requires stimulation from the environment

5. The immature brain’s lack of specialization has plasticity (a benefit)

What are the memory regions that continue to develop throughout childhood?

The medial temporal lobe that contains the hippocampus and prefrontal cortex

At what age is there a slight decrease in hippocampus volume seen?

Middle age

What happens when the hippocampus is developing during adolescences? What does it indicate?

Complex memories are encoded indicating the development of the hippocampus and connection with the prefrontal cortex

Which brain lobes are associated with language?

Frontal and temporal

What are the two specific areas associated with language? Where are they?

Broca’s area → inferior frontal gyrus

Wernicke’s area → superior temporal gyrus

In childhood, what is there a rapid increase of in language related areas?

Synaptic growth

In adolescence, what is there an increase of that supports complex language processing?

Connectivity between Broca’s area and Wernicke’s area

A decrease of what tissue in the brain in older age may impact language processing speed?

Gray matter

When is the peak development of the prefrontal cortex?

Young adulthood

What decreases in older adulthood in the prefrontal cortex?

Connectivity and volume

What develops first: limbic system or prefrontal region?

Limbic system

What is the limbic system responsible for?

Seeks pleasure, motivation, rewards and risky behaviour

What is the prefrontal region responsible for in terms of the limbic system?

Executive functions and behavioural self-control

Use this graph to explain how it relates to behaviour

The limbic system, which is the pleasure-seeking and reward center, is fully active. But the prefrontal regions, which is the self-control, is not fully developed. Therefore, risky (rewarding) behaviours will occur even if there are consequences because of the limited self-control

Connections between which regions occur in adolescences that often result in heightened emotions?

Amygdala and prefrontal cortex

The cortical maturation continues until at least what age?

30 years old

Which cortical area matures first?

Primary cortical regions

Areas responsible for spatial and language skills mature when?

Puberty

Which cortical area matures last?

Tertiary cortical areas

Cognitive developmental has several types of intellectual abilities. What is the term to describe that?

Multidimensional

Intelligence can improve or decline during adulthood. What is the term to describe that?

Multidirectional

What is fluid intelligence?

Involves flexible, adaptive thinking, ability to reason and solve novel problems

What is crystallized intelligence?

Involves the knowledge, facts and skills we know through experience

Which type of intelligences declines throughout adulthood?

Fluid intelligence

Which type of intelligences improves over time?

Crystallized intelligence

What is important for recognizing faces, voices and movement in infancy (development of memory)?

Sensory and motor memory

How do infants communicate in infancy?

Through gestures, sounds and expressions

In the cross-sectional data study, what are the cognitive declines and when do they start?

Declines are seen in all domains except for verbal and numeric ability. Starts before age of 55

In the longitudinal data study, what are the cognitive declines and when do they start?

Declines are only seen in processing speed before age of 55 and all other domains after 55

Cross-sectional results of cognitive performance may be influenced by what?

Cohort effects

What are cumulative abilities that built over time?

Crystallized abilities

What are abilities that require flexibility of cognitive processing at time of test?

Fluid abilities

What are examples of fluid abilities?

Processing speed, attention, task-switching

What are examples of crystallized abilities?

General knowledge, vocabulary

In older adults, which type of attention is preserved?

Sustained attention

In older adults, which type of attention declines?

Divided attention and selective attention

Which types of memories are most preserved?

Short term memory (and most of long term semantic memory)

Which types of memories declines the most?

Long term episodic memory (most decline) and working memory

What remains stable for language development?

Vocabulary and semantic memory

What declines for language development?

Visual confrontation naming and verbal fluency

Which type of abilities (intelligence) remains stable over time?

Crystallized abilities

Which type of abilities (intelligence) declines with age?

Fluid abilities

When does the total cerebrum volume peak at?

Just before the onset of puberty

When does gray matter volume peak at?

Around 6 years old

When does subcortical gray matter volume peak at?

Mid-puberty

When does white matter volume peak at?

Young adulthood

When was the rate of growth of GMV, WMV and sGMV at its max?

Infancy and early childhood