Answers to reading guide - Book Developmental Neuropsychology

Reading guide: Book
Developmental Neuropsychology. A clinical approach
(2019). second edition. Vicky Anderson, Elisabeth Northam,
and Jacquie Wrennall.
Chapter 1 Child neuropsychology: theory and practice
 What is child neuropsychology?
o Child neuropsychology (or paediatric neuropsychology) refers to the study of brain-
behaviour relationships within the context of an immature but rapidly developing
brain and the implementation of the knowledge gained into clinical practice.
o Child neuropsychology informs our understanding of typical child development by
providing a framework within which to explore and map parallels between brain
maturation and cognitive and socio-emotional development.
o The primary focus for the field of child neuropsychology has been the generation of a
developmentally informed knowledge base that facilitates optimal understanding of
the impact of early brain injury, insult or disruption on subsequent brain development
and child function, guiding the design of evidence-based interventions to minimise
disability.
 What does plasticity, vulnerability, ’growing into deficits’, and critical periods mean?
o Plasticity:
 The ability of the brain to modify its connections or re-wire itself.
 The immature brain possesses great flexibility that facilitates good recovery
and outcome
 Relative sparing of function following early brain insult
 Kennard principle: impairments are smaller when lesions occur in
infancy than when they take place in adulthood
 A theory of recovery of function where the young child’s brain is seen to be
less differentiated than that of the mature adult and more capable of
transferring functions from damaged cerebral tissue to healthy tissue.
 Neural plasticity: the brain’s response to the environment, refers to
physiological processes at molecular, cellular, neurochemical and
neuroanatomical levels and at the level of brain systems
 Functional plasticity: refers to behavioural change or recovery occurring in
response to environmental or injury-related events.
Once the genetically predetermined sequence of brain maturation has
been disrupted, neural recovery may not necessarily translate to functional
recovery.
o Vulnerability:
 The developing brain is uniquely susceptible, with early brain insult leading to
incomplete recovery and poor outcome.
 The earlier the damage occurs, the more serious the effects.
o Growing into deficits:
 The phenomenon that the effects of early brain damage on development are
cumulative as more functions are expected to mature, leading to global
neurological disorders in later life.
 When they get older the deficits are seen.

,  Certain problems may only become apparent at a later age. The problems
were always there, but were not noticed, because at the age of the child
these skills were not yet used. No new problem has arisen, but a problem that
already existed has now become clear.
o Critical periods:
 The time window during which external influences have a significant effect
 Early brain insult will have different consequences at different times
throughout development and, in some instances, may be more detrimental
than later injury, because some aspects of cognitive development are
critically dependent on the integrity of particular cerebral structures at
certain stages of development.
 Thus, if a cerebral region is damaged or dysfunctional at a critical stage of
cognitive development, it may be that the cognitive skill subsumed by that
region is irreversibly impaired.
 The development of certain cognitive function depends on the proper
functioning of certain areas of the brain in a certain stage of development
 Describe the biopsychosocial model in this chapter. What are the dimensions?
o Threats to healthy development are numerous and span multiple domains from
health and environment to cognitive development, mental health and quality of life.
With recent advances in neuroimaging and genetics, we now have tools that can
more comprehensively explore the interacting influences of biology and environment.
 Need to build robust cross-discipline collaborations, which will lead to
combined knowledge, which can then be translated into ‘best’ practice in the
field to enhance optimal outcomes for individual children and for the benefit
of the community.
o To improve prediction of outcome by measuring the interacting influences of neural,
cognitive and psychosocial parameters and their ever-changing matrix through
childhood.
o The dimensions are:
 Brain: the ‘bio/neuro’ dimension
 Environment: the ‘social’ dimension
 Child cognitive and socio-emotional function: the ‘psych’ dimension

,Chapter 2 The developing brain (see also lecture by Chris
Dijkerman)
 What is the current view on brain organization?
o The current view on the brain organization is the ‘connectionist view’ (see next
question)
 What is the difference between modular organization and the connectionist view?
o Modular organization: this approach attributes the processing of particular
behavioural functions to distinct cortical regions, connected via specific functional
neural networks or circuits.
o Connectionist view: recent evidence, mainly from sophisticated neuroimaging studies,
challenges the localizationist approaches (like modular organization), proposing that
many behaviours and skills are mediated by complex neural networks, incorporating
both frontal and extra-frontal systems. In the developing brain, both structures and
connectivity are rapidly developing and evidence suggests that functional
organisation is incomplete
o The difference is that in the connectionist view, neural networks work together for
certain skills and behaviours  and in the modular view, distinct cortical regions
process particular functions.
 Describe the three views Mark Johnson distinguishes
o He highlights the importance of also accounting for the influence of genetics and
experience on the developing organisation of the brain, reflecting an ‘interactive
specialisation approach’.
o M. Johnson acknowledges these influences and identifies three separate, but not
necessarily incompatible, approaches to understanding progression of cognitive
abilities in infants:
 Maturation
 Interactive specialisation
 Skill learning
o Maturational view: proposes there is a genetically predetermined, developmental
sequence of specific neuroanatomical regions, which provides the foundation for the
hierarchical emergence of sensory, motor, and cognitive processes.
o Interactive specialisation: suggests that emergence of a new skill reflects refinement
of connectivity between brain regions, not just activity in one or more region.
o Skill learning: is based on the observation that patterns of brain activation change
during skill acquisition. The immature brain needs to recruit more brain regions to
successfully complete an activity than does the healthy adult brain. There is an
association between performance and emerging patterns of interactions between
different regions.
 What are important characteristics of and difference between prenatal and postnatal
development?
o Difference between prenatal and postnatal development?
 The fastest rate of brain growth occurs prenatally.
 Prenatal development is primarily concerned with the structural formation of
the CNS and is thought to be largely genetically determined. Interruptions to
development during this period via genetic mechanisms or interuterine
trauma or infection are likely to have a dramatic impact on cerebral

, structure, so that the brain’s morphology appears abnormal even at a
macroscopic level
 Post-natal development is mostly characterised by elaboration of the brain,
in particular dendritic arborisation, myelination and synaptogenesis. These
processes are thought to be more susceptible to the impact of neuronal
activity and this to environmental and experiential influences than genetics.
Brain damage sustained postnatally may have less impact on gross brain
morphology, but is likely to interfere with ongoing CNS elaboration and
interrupt the development of interconnections and functional neural
networks.
o Important concepts of prenatal development:
 Neurulation
 Rapid generation of cells within the system and includes two main
classes of cells: neurons and glial cells, produced by division of
neuroblasts and glioblasts. The neuron is the basic functional unit of
the CNS and is responsible for neural transmission within the brain.
Glial cells play a supportive and nutrient role within the CNS,
enabling regeneration of damaged neurons, producing scar tissue to
occupy damage sites and transporting nutrients from nerve cells.
 Neural plate  forms neural tube  neurulation takes place in here
 Proliferation (2-5 months)
 The developmental stage during which neurons intended to form the
cerebral cortex are generated, and it occurs from gestational weeks 6
to 18.
 Specific cell populations emerge in unique locations within the neural
tube and will later develop into specific cerebral structures.
 Migration (2-5 months)
 Neuroblasts (from which neurons are later derived) migrate to their
permanent locations, mostly in a radial pattern, travelling along
radial glial fibres via previously generated neurons.
 Dendritic development and synaptogenesis
 Critical for the establishment of cerebral connections.
 As axons extend and dendrites arborise, the developing brain
becomes densely packed and the brain surface begins to fold (sulci
and gyri) to accommodate this increased cortical mass.
 Differentiation
 Once neurons have migrated, differentiation begins, with cells
becoming committed to specialised systems, relevant connections
being established and functional activity commencing. Cells not
associated with these functional systems may be eliminated.
 Apoptosis
 A form of programmed cell death that eliminates cells with poor or
unnecessary synaptic connections, results in degeneration of nearly
half of all neurons during development.
 these processes underpin the transformation of the primitive neural tube into
a series of complex neural networks comprising the CNS.
o Important concepts of postnatal development:
 Growth of short cortico-cortical connections