Task 3: Brainy Methods

Question 1

Zygote

Answer 1

fertilised egg (containing 46 chromosomes with genetic recipes for the development of a new individual)

Question 2

Discuss the development from zygote to neural tube

Answer 2

• 12 hrs – single cell begins dividing
• 3 days – small mass of homogeneous cells
• 1 week – emerging embryo shows 3 distinct layers
• > Ectoderm – outer cellular layer that develops into skin & NS
• > Mesoderm
• > Endoderm
• 20 days – neural groove begins to develop (becomes midline, groove between neural folds)
• 22 days – neural groove closed to form neural tube

Question 3

Discuss how the neural tube develops into the subsections of the brain

Answer 3

24 days – at head end of neural tube, fore-, mid- & hindbrain become apparent

• > Forebrain (prosencephalon = telencephalon + diencephalon)
• > Midbrain (mesencephalon)
• > Hindbrain (rhombencephalon = metencephalon + myelencephalon)

Question 4

When does the embryo become a fetus?

Answer 4

10 weeks

Question 5

When do the major brain regions develop?

Answer 5

11 weeks

Question 6

Name the 6 developmental stages of the nervous system

Answer 6

1. neurogenesis
2. cell migration
3. differentiation
4. synaptogenesis
5. neuronal cell death
6. synapse rearrangment

Question 7

Neurogenesis

Answer 7

production of nerve cells

Question 8

Cell migration

Answer 8

movement of cells from site of origin to final location

Question 9

Adult neurogenesis

Answer 9

generation of new neurons in some areas of the adult brain (mostly hippocampus and olfactory organ)

Question 10

Radial glial cells

Answer 10

extend from inner to outer surface of emerging nervous system (spanning width of emerging cerebral hemispheres) and guide migrating neurons
-> New neurons creep along them to higher layers of cortex

Question 11

Cell adhesion molecules

Answer 11

protein on surface of a cell, promote adhesion of developing NS elements, guide migrating cells & growing axons
-> May also guide axons to regenerate when cut in adulthood

Question 12

Cell differentiation

Answer 12

once cells reach destination they express genes (i.e. transcribe a particular subset of genes to make the specific proteins they need)

Question 13

2 influences on cell differentiation

Answer 13

1. Cell-autonomous differentiation:directed by cell itself (intrinsic self-organization) rather than influence of other cells, only the genes within the cell are directing events
2. induction: cell-cell interaction – one set of cells influences the fate of neighbouring cells

Question 14

Synatogenesis

Answer 14

establishment of synaptic connections as axons and dendrites grow

Question 15

Process outgrowth

Answer 15

extensive growth of axons and dendrites

Question 16

Growth cones

Answer 16

specialised swellings (growing tip) of an axon/ dendrite
-> dendritic cones – found in adults, mediating the continued elongation + change in dendrites that occurs throughout life in response to experience

Question 17

Filopodia

Answer 17

fine tubular outgrowths from the growth cone

-> adhere to CAMs in extracellular environment and contract to pull cone in particular direction

Question 18

Chemoattractant

Answer 18

attract particular classes of axonal growth cones

Question 19

Chemorepellents

Answer 19

repel particular classes of axonal growth cones

Question 20

Neural apoptosis

Answer 20

death of many neurons as normal part of development for synaptic pruning

Question 21

Death genes

Answer 21

case cells to actively decied to die and commit suicide (carried by chromosomes and released when they die)

Question 22

Neurotrophic factor

Answer 22

target derived chemical that acts as if it “feeds” certain neurons to help them survive – neurons that receive enough survive, those that don’t die

Question 23

Nerve growth factor

Answer 23

substance that markedly affects growth of neurons in ganglia of sympathetic NS

Question 24

Synaptic pruning

Answer 24

refers to the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions.

Question 25

Synaptic remodelling/rearrangment

Answer 25

loss of some synapses and development of others

Question 26

Myelinaton

Answer 26

development of sheaths around axons, change rate at which axons conduct messages, allows large network of cells to communicate rapidly (through glial cells)

Question 27

Mature cognition

Answer 27

ability to filter & suppress irrelevant information and actions (sensorimotor actions) in favour of relevant ones (cognitive control)

Question 28

Immature cognition

Answer 28

enhanced sensitivity to interference from competing sources that coincide with immature association cortex
-> shift from diffuse to more focal recruitment

Question 29

Microgenetic design

Answer 29

Children are observed intensively over a relatively short period of time while a change is occurring

Question 30

Sequential design

Answer 30

Combines longitudinal and cross-sectional approaches

Question 31

Sensation-seeking

Answer 31

inclination to seek varied, novel, complex and intense sensations and experiences and the willingness to take physical, social, legal and financial risks for the sake of such experiences

Question 32

Self-regulation

Answer 32

constructs that refer to capacity to deliberately modulate one’s thoughts, feelings or actions in the pursuit of planned goals

-> among these constructs are impulse control, response inhibtion, emotion regulation and attentional control

Question 33

Discuss the “hot” pathway

Answer 33

limbic system, decision-making in high emotional conditions (irrational-hot)

-> hypersensitivty during adolescence

Question 34

Discuss the “cold” pathway

Answer 34

prefrontal cortex, decision making in low emotional conditions (rational-cold)

Question 35

Cognitive control pathway

Answer 35

network of brain regions involved in self-regulation

Question 36

Affective pathway

Answer 36

network of brain regions involved in emotions