33. Neurodevelopmental Disorders - Introduction Flashcards
Define
Critical period
a maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli
Define
Neurodevelopmental disorder
impairments of the growth and development of the brain and/or central nervous system
Define
Cerebral cortex
Responsible for sensing, thinking, learning, emotion, consciousness and voluntary movement
Define
Amygdala
Part of the limbic system involved in emotion and aggression
Define
Cerebellum
Structure that coordinates fine muscle movement and balance
Define
Hypothalamus
Responsible for regulating basic biological needs: hunger, thirst, temperature control
Define
Hippocampus
Part of the limbic system involeved in learning and memory
Define
Medulla
Responsible for regulating largely unconsicious functions such as breathing and circulation
Define
Neocortex
the large 6-layered dorsal region of the cerebral cortex that is unique to mammals
Define
Gastrula
an early metazoan embryo in which the ectoderm, mesoderm, and endoderm are established either by invagination of the blastula (as in fish and amphibians) to form a multilayered cellular cup with a blastopore opening into the archenteron or by differentiation of the blastodisc (as in reptiles, birds, and mammals) and inward cellular migration
Define
Ectoderm
the outermost of the three primary germ layers of an embryo that is the source of various tissues and structures (such as the epidermis, the nervous system, and the eyes and ears)
Define
Neural tube
the hollow longitudinal dorsal tube formed by infolding and subsequent fusion of the opposite ectodermal folds in the vertebrate embryo that gives rise to the brain and spinal cord
Define
Notochord
Rod-like structure in the middles of the embryo that secretes factors that provide position and fate information
Define
Circuit formation
Growth of axons and dendrites followed by synapse formation (synaptogenesis)
Define
Radial glial cell
bipolar-shaped progenitor cells that are responsible for producing all of the neurons in the cerebral cortex
Define
Ventricular zone
a transient embryonic layer of tissue containing neural stem cells, principally radial glial cells, of the central nervous system (CNS)
Define
Tangenital migration
the movement of interneurons from the ganglionic eminence to the cerebral cortex
Define
Ganglionic eminence
a transitory structure in the development of the nervous system that guides cell and axon migration. It is present in the embryonic and fetal stages of neural development found between the thalamus and caudate nucleus
Define
Autism spectrum disorder (ASD)
any of a group of developmental disorders marked by impairments in the ability to communicate and interact socially and by the presence of repetitive behaviors or restricted interests
Define
Schizophrenia
a mental illness that is characterized by disturbances in thought (such as delusions), perception (such as hallucinations), and behavior (such as disorganized speech or catatonic behavior), by a loss of emotional responsiveness and extreme apathy, and by noticeable deterioration in the level of functioning in everyday life
Define
GABA
an amino acid C4H9NO2 that is a neurotransmitter which induces inhibition of postsynaptic neurons
Definition
a maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli
Critical period
Definition
impairments of the growth and development of the brain and/or central nervous system
Neurodevelopmental disorder
Definition
Responsible for sensing, thinking, learning, emotion, consciousness and voluntary movement
Cerebral cortex
Definition
Part of the limbic system involved in emotion and aggression
Amygdala
Definition
Structure that coordinates fine muscle movement and balance
Cerebellum
Definition
Responsible for regulating basic biological needs: hunger, thirst, temperature control
Hypothalamus
Definition
Part of the limbic system involeved in learning and memory
Hippocampus
Definition
Responsible for regulating largely unconsicious functions such as breathing and circulation
Medulla
Definition
the large 6-layered dorsal region of the cerebral cortex that is unique to mammals
Neocortex
Definition
an early metazoan embryo in which the ectoderm, mesoderm, and endoderm are established either by invagination of the blastula (as in fish and amphibians) to form a multilayered cellular cup with a blastopore opening into the archenteron or by differentiation of the blastodisc (as in reptiles, birds, and mammals) and inward cellular migration
Gastrula
Definition
the outermost of the three primary germ layers of an embryo that is the source of various tissues and structures (such as the epidermis, the nervous system, and the eyes and ears)
Ectoderm
Definition
the hollow longitudinal dorsal tube formed by infolding and subsequent fusion of the opposite ectodermal folds in the vertebrate embryo that gives rise to the brain and spinal cord
Neural tube
Definition
Rod-like structure in the middles of the embryo that secretes factors that provide position and fate information
Notochord
Definition
Growth of axons and dendrites followed by synapse formation (synaptogenesis)
Circuit formation
Definition
bipolar-shaped progenitor cells that are responsible for producing all of the neurons in the cerebral cortex
Radial glial cell
Definition
a transient embryonic layer of tissue containing neural stem cells, principally radial glial cells, of the central nervous system (CNS)
Ventricular zone
Definition
the movement of interneurons from the ganglionic eminence to the cerebral cortex
Tangenital migration
Definition
a transitory structure in the development of the nervous system that guides cell and axon migration. It is present in the embryonic and fetal stages of neural development found between the thalamus and caudate nucleus
Ganglionic eminence
Definition
any of a group of developmental disorders marked by impairments in the ability to communicate and interact socially and by the presence of repetitive behaviors or restricted interests
Autism spectrum disorder (ASD)
Definition
a mental illness that is characterized by disturbances in thought (such as delusions), perception (such as hallucinations), and behavior (such as disorganized speech or catatonic behavior), by a loss of emotional responsiveness and extreme apathy, and by noticeable deterioration in the level of functioning in everyday life
Schizophrenia
Definition
an amino acid C4H9NO2 that is a neurotransmitter which induces inhibition of postsynaptic neurons
GABA
What are the three germ layers?
Ectoderm
Mesoderm
Endoderm
Which germ layer does the nervous system originate from?
Ectoderm
At the end of week 3 of gestation, the ________induces the formation of _________ from the ectoderm, which then folds and fuse to form the neural tube.
At the end of week 3 of gestation, the notochord induces the formation of neural plate from the ectoderm, which then folds and fuse to form the neural tube.
What does the forebrain, midbrain and hindbrain differentiate into?
Forebrain:
- Telecephalon (Cerebrum)
- Diencephalon (Hypothalamus)
Midbrain:
- Mesencephalon (Brainstem)
Hindbrain:
- Melencephalon (Pons and cerebellum)
- Myelencephalon (Medulla)
How do excitatory neuron migrate?
Excitatory neurons attach to radial glial cells allowing them to migrate from the ventricular zone to the surface of the brain
Where are excitatory neurons “born”?
Ventricular zone
Where are inhibitory neurons “born”?
Ganglionic eminence
How do inhibitory neurons migrate?
There are no radial glial cells to attach to so they “swim” from the ganglionic eminence towards the surface of the brain based on guidance cues
Which neurons are primarily found in layers 2 and 3?
Inhibitory neurons
During what stage does the vast majority of the congenital abnormalities occur?
Embryonic stage of prenatl development
What are the two stages of prenatal development?
Embryonic
Fetal
What is the characteristics of the brain at birth?
Gross anatomy of CNS resembles adult
Repertoire of neurons of neocortex are largely established
What happens to the brain during infancy?
Massive outgrowth of dendrites and axons
Synaptogenesis, gliogenesis, myelination
Neurogenesis in cerebellum still occurring,
What structural changes occur in the adolescent brain?
Reduction in grey matter of neocortex – pruning of synapses
Increases in white matter – increased myelination and connectivity
Axonal sprouting and growth in circuits in the amygdala and cortex
What behaviour changes occur due to the structural changes of the adolescent brain?
Increased social behaviour
Novelty and sensation seeking
Tendencies towards risk taking
Emotional instability
Impulsivity
Dominance of peer relationships
What are the three main critical periods and when do they occur?
Senses (infancy)
Language (late infancy/early childhood)
Higher cognition (childhood)
What causes neurodevelopmental disorders?
deficits in neurogenesis, progenitor cell proliferation, migration, synapse formation and myelination during embryogenesis
What is the role of GABA in neuronal development?
- During embryonic and early postnatal development, GABA is excitatory
- GABA is crucial for generating synchronised patterns of activity of developing networks
- GABA switches from excitatory to inhibitory at birth potentially to protect neurons from hypoxia
What is the excitatory/inhibitory theory for neurodevelopmental disorders?
Alterations in the ratio of excitatory to inhibitory cortical activity contribute to NDD
