Development of the Nervous System Flashcards
What are the five stages of neurodevelopment?
- Induction of the neural plate
- Neural proliferation
- Migration and Aggregation
- Axon growth and Synapse formation
- Neuron death and Synapse rearrangement
What are the three germ layers?
Ectoderm
Mesoderm
Endoderm
The growing neural plate folds to form the ________, and then the lips of this fuse to form the ________
Neural groove; Neural tube
What does the inside of the neural tube eventually develop into?
Cerebral ventricle and Spinal canal
Which part of the neural tube has the highest rate of proliferation?
Ventricular zone
What is migration that involves cells moving from the ventricular zone in a straight line outward towards the outer wall of the tube called?
Radial migration
What is migration that involves cells moving parallel to the neural tube’s walls called?
Tangenital migration
What is the structure situated just dorsal to the neural tube called?
Neural crest
What does the neural crest eventually develop into?
The neurons and glial cells of the peripheral nervous system
What is the amoebalike structure that extends from the growing tip of an axon or dendrite called?
Growth cone
The hypothesis that each postsynaptic surface in the nervous system releases a specific chemical and that each growing axon is attracted by the label to its postsynaptic target during both neural development and regeneration is called…
Chemoaffinity hypothesis
What does the chemoaffinity hypothesis fail to account for?
Growing axons that follow the same circuitous route to reach their target in every member of a species rather than growing directly to it
What are the first growth cones to travel along a particular route called?
Pioneer growth cones
What is the tendency of developing axons to grow along the paths established bu preceeding axons called?
Fasciculation
What is the hypothesis that states that axons growing from one topographical surface to another are guided to specific targets that are arranged on the terminal surface in the same way that the axons’ cell bodies are arranged on the original surface called?
Topographical gradient hypothesis
Why is apoptosis safer than necrosis?
Necrosis causes cells to break apart and spill their contents into extracellular fluid which can cause inflammation. In apoptotic cell death, DNA and other internal structures are cleaved apart and packaged in membranes before the cell breaks apart
Which part of the brain of nonhuman adult mammal undergoes substantial neurogenesis?
Hippocampus and Olfactory bulbs
Which part of the adult human brain undergoes substantial neurogenesis?
Hippocampus and Striatum
What increased the speed of axonal conduction?
Myelination
Lack of, or incomplete, schema of object performance is referred to as what?
Perseverative error
Various parts of the ______ play various roles, with working memory being one of them
Prefrontal cortex
Experiences that contribute to the information in genetic programs are called _______ experiences?
Instructive
The two important periods of development are the critical and the ______ period
Sensitive
An experimental technique used by neuroscientists to study central nervous system plasticity is called _______
Monocular deprivation
Roe and colleagues performed a study involving surgically altering the ______ of ferrets
Axons
Before the nervous system is full developed, _________ begin to fire and begin to interact with environment
Neurons
The output in the _____ goes primarily to the amygdala and piriform cortex
Olfactory bulbs
Adult-generated olfactory bulbs and striatal neurons become interneurons, and adult-generated hippocampal neurons become ______
Granule cells
________ refers to the ability to separate distinct percepts into individual memories for storage
Pattern seperation
Experience in adulthood can lead to reorganisation of sensory and ______ maps
Cortical
What are the core symptoms of Autism Spectrum Disorder?
A reduced capacity for social interaction and communication
Restricted and repetitive patterns of behaviour, interests, or activities
What are the core symptoms of Williams Syndrome?
An increased capacity for social interaction and communication
What is aggregation?
the alignment of neurons during the development of the nervous system
What is apoptosis?
cell death that is actively induced by genetic programs; programmed cell death
What is Autism spectrum disorder (ASD)?
a complex neurodevelopmental disorder characterized by a reduced capacity for social interaction and communication and restricted and repetitive patterns of behavior, interests, or activities
What are cell-adhesion molecules (CAMs)?
molecules on the surface of cells that have the ability to recognize specific molecules on the surface of other cells and adhere to them
What is the chemoaffinity hypothesis?
the hypothesis that growing axons are attracted to the correct targets by different chemicals released by the target sites
What are connexins?
Narrow tubes that bridge the gap junction between two cells through which cells can exchange cytoplasms
What is a critical period?
a period during development in which a particular experience must occur for it to influence the course of subsequent development
What is the ectoder,?
one of the three primary germ layers in the developing embryo that consists of the most exterior (distal) layer
What is the endoderm?
one of the three primary germ layers in the developing embryo that consists of the innermost layer
What is fasciculation?
the tendency of developing axons to grow along the paths established by preceding axons
What is glia-mediated migration?
one of two major modes of neural migration during development, by which immature neurons move away from the central canal along radial glial cells
What is a growth cone?
amoeba-like structure at the tip of each growing axon or dendrite that guides growth to the appropriate target
What are instructive experiences?
particular experiences that contribute to the information in genetic programs and influence the course of development
What are interneurons?
neurons with short axons or no axons at all, whose function is to integrate neural activity within a single brain structure
What is the mesoderm?
the middle of the three cell layers in the developing embryo
What is migration?
the movement of cells from their site of creation in the ventricular zone of the neural tube to their appropriate target location
What does multipotent mean?
capable of developing into different cells of only one class of cells (e.g., different kinds of blood cells)
What is necrosis?
passive cell death
What is nerve growth factor (NGF)
the first neurotrophin to be discovered
What is the neural crest?
a structure situated just dorsal to the neural tube. It is formed from cells that break off from the neural tube as it is being formed
What is the neural plate?
a small patch of ectodermal tissue on the dorsal surface of the vertebrate embryo, from which the neural groove, the neural tube, and, ultimately, the mature nervous system develop
What is neural proliferation?
the rapid increase in the number of neurons the follows the formation of the neural tube
What is neurogenesis?
the growth of new neurons
What are neutrophins?
chemicals that are supplied to developing neurons by their targets and that promote their survival
What is the olfactory bulb?
a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell
What is the optic tectum?
the main destination of retinal ganglion cells in non-mammalian vertebrates
What is the orbitofrontal cortex?
the cortex of the inferior frontal love, adjacent to the orbits, which receives olfactory input from the thalamus
What is pattern separation?
the ability to separate distance percepts into individual memories for storage
What are permissive experiences?
experiences that permit the information in genetic programs of brain development to be expressed and maintained
What is perseveration?
the tendency to continue making a formerly correct response that is currently incorrect
What are pioneer growth cones?
the first growth cones to travel along a particular route in the developing nervous system
What does pluripotent mean?
cells that can develop into many, but not all, classes of the body cells
What are radial glial cells?
glial cells that exist in the neural tube during the period of neural migration and that form a network along which radial migration occurs. Some radial glial cells are stem cells
What is radial migration?
movement of cells in the developing neural tube from the ventricular zone in a straight line outward towards the tube’s outer wall
What are retinal ganglion cells?
retinal neurons whose axons leave the eyeball and form the optic nerve
What are savants?
individuals with developmental disabilities who nevertheless display amazing and specific cognitive or artistic abilities; savant abilities are sometimes associated with autism spectrum disorder
What is a sensitive period?
an interval of time during development when an experience can have a greater effect of development if it occurs during that interval, as opposed to outside that interval
What is somal translocation?
one of two major modes of neural migration, in which an extension grows out from the undeveloped neuron and draws the cell body up into it
What are stem cells?
cells that have an almost unlimited capacity for self-renewal and the ability to develop into many different types of cells
What is the striatum?
a structure of the basal ganglia that is the terminal of the dopaminergic nigrostriatal pathway
What is the superior temporal gyrus?
the large gyrus of the temporal lobe adjacent to the lateral fissure; the location of the auditory cortex
What is synaptogenesis?
the formation of new synapses
What is tangenital migration?
movement of cells in the developing neural tube in a direction parallel to the tube’s walls
What is topological gradient hypothesis?
the hypothesis that axonal growth is guided by the relative position of the cell bodies on intersecting gradients, rather than by point-to-point coding of neural connections
What does totipotent mean?
capable of developing into any type of body cell
What does unipotent mean?
cells that can develop into only one types of cell
What is the ventricular zone?
the region adjacent to the ventricle in the developing neural tube
What is Williams syndrome?
a neurodevelopmental disorder characterized by intellectual disability, accompanied by preserved language and social skills
What is a zygote?
the cell formed from the amalgamation of a sperm cell and an ovum
