Chap 4 - Infant State (MIDTERM 2) Flashcards
(123 cards)
What are the 2 main physical changes when it comes to the infant’s body?
Change in body size ans muscle-fat makeup.
- Height increases 50% by age 1 and 75% by age 2, which is very fast
- Weight doubles by age 6 months and triples by age 1
What are neurons?
Nerve cells that store and transmit information
What are the different part of a neuron and their functions?
Dendrites: getting signals from other cells
Cell body with soma: when NT are synthesized and generated
Axon: long tail-like structure that speeds up the message
Myelin sheath: fat-like substance surrounding the axon that speeds up the connection and the release of the message
Axon terminal: allows for neurons to communicate with one another
What is a NT? What is the difference between inhibitory NT and excitatory NT?
NT: chemicals released by neurons that cross the synapse
Inhibitory NT calm down and inhibit the NS
Excitatory NT stimulate the NS and make individuals more alert
What is the synaptic gap?
Space between two neurons in which the NT and released and the message is sent from one neuron to the next
What is meant by synaptogenesis?
Synaptogenesis is the proliferation of neural connections. We want the neurons to be connected for the NT to be transferred from one neuron to the next
What is the process of myelination?
It is the formation of fatty layer encasing axons
What is the process of synaptic pruning? Why is it occurring? Why is it relevant in toddlerhood?
It is the reduction of unused synapses and/or neurons. Its purpose is to clean the NS and to make it as efficient as possible, and so it reduces all irrelevant messages/connections that don’t serve.
Considering that the brain gets rid of the unused neurons, it is important important to stimulate the toddler as much as possible in many areas so that the brain develops properly.
When does the brain circumstance significantly increase? What about brain volume? Does it stop afterwards?
Both in the first 4-5 years of life. Growth continues and never stops.
What is a newborn reflex?
An automatic response or action programmed by brain centres
Name and describe 6 newborn reflexes
Rooting: responses when you have your cheeked touched/stimulated
Sucking: as soon as anything comes close to mouth, you suck
Grasping: grasping reflex (bending reflex)
Moro: responses to sudden loss of support (i.e. feeling that pressure of arms holding him is gone –> raising arm to be in caregiver’s arms)
Stepping: when holding baby on flat surface, they’ll attempt to walk
Babinski: tickling the foot –> toes turning upwards
What are three ways to assess brain functioning?
- Electroencephalogram (EEG)
- Functional Magnetic Resonance Imaging (fMRI)
- Positron Emission Tomography (PET)
What is the purpose of EEG? How does it work?
EEG aims to measure electrical activity in the brain, and it can be performed on toddlers and newborns. It allows to see the functioning of the brain through the brain waves. It is quite quick, yet not very precise. It allows to see the whole picture.
How does fMRI work? What is its purpose?
The idea is that a huge magnetic field is being generated, which gets the molecules excited for a while until they go back to resting state. While they are going back to their resting state, a signal is emitted and depending on where the signal was in the first place, you can get a better idea of what is going on in the brain. It has a better resolution than PET scan. You can make the person carry out a task and can look a the activity in the brain (easier to do on newborns compared to toddlers).
How does PET scan works? Where is the injection done? Is it used on newborns and toddlers? One downfall?
The person is injected with a radioactive tracer substance, and all parts of brain that are active light up.
The substance is radioactive but breaks down very quickly (from minutes to hours).
Injection is done in the blood brain barrier, and the aim is for the substance to bind to whatever is of interest.
Not used on newborns or toddlers, can use in mid-childhood. It takes a long time.
What are the difference ways in which PET scans can be used?
- Comparing healthy individuals with a trauma population to see the repercussions on brain activity (which regions are less activated?)
- Looking at the impact of antidepressant on the brain
What are the two brain hemispheres and what are they mainly responsible for?
Left hemisphere: verbal, analytic process
Right hemisphere: spatial, holistic processing
In what is the left hemisphere involved? What happens when the left hemisphere is damaged?
Left hemisphere is involved in verbal skills and processes related to language, such as hearing, understanding, producing. It is also analytic in a sense that looks for more precise symptoms.
When damaged, you won’t be able to focus on facial details of others.
In what is the right hemisphere involved? What happens when it’s damaged?
The right hemisphere is involved in space, orientation, and layout. It is holistic in a sense that it processes things as a whole rather than specific parts
When damaged, you would be able to describe specific details, but not the overall picture.
What is brain lateralization?
Idea that certain functions are located on one side of the brain i.e. language on left side
What is brain plasticity?
It is the brain’s ability to adapt, which is quite important in early life since the brain is malleable and vulnerable.
Plasticity is the idea that the brain is creating new connections. For instance, certain brain regions are much more developed in taxi drivers as they need to be well oriented in their city.
What is a sensitive period?
A sensitive period is a period in which an organism undergo certain changes, where the NS is developing, and so it could easily be impaired. For instance, as the brain is growing (4-5 years old), the brain is more reactive to environmental stressors, which makes it more vulnerable. As such, the first years of life are a sensitive period of the brain.
What is an experience-expectant brain growth?
Development of brain depending on expected ordinary experiences (i.e hearing human speech) –> you would expect a baby to be exposed to human speech and human touch. If some events are expected to happen and don’t happen, it may lead to problems. It is linked to a sensitive period.
What is an experience-dependent brain growth?
It is the refinement of established brain structures as a result of specific learning experiences that vary widely across individuals and cultures. This type of experience is not expected, but rather an additional skill that a person may develop, which will affect the brain structure. It is not linked to a sensitive period.