Week 5 - Reconsidering ‘abnormality’ and mental health in brain development Flashcards
What is lissencephaly?
A congenital condition associated with changes in the migration of cortical neurons which affects brain development and functioning
What is the name for the congenital condition which is associated with changes in the structure and appearance of the cerebral cortex?
Lissencephaly
Is lissencephaly considered to be a mental health condition?
No
Which virus can cause microencephaly?
Zika
What is the name for a condition which is associated with smaller than usual head size at birth?
Microencephaly
What is the name for a syndrome which is a subtype of type 1 lissencephaly?
Miller-Dieker syndrome
What does the term syndrome denote?
A group of symptoms that, together, indicate the presence of a health condition
What is meant by the term ‘spectrum’ in the context of health conditions?
The occurrence of a set of symptoms ranging in severity
On which chromosome is the Miller-Dieker gene located?
Chromosome 17
What happens to the LIS1 gene in people who have Miller-Dieker syndrome?
It is deleted
What does the LIS1 gene code for?
A protein called platelet activating factor acetylhydrolase isoform 1B subunit 1 (PAFAH~1~B~1~)
PAFAH~1~B~1~ is an enzyme which interacts with what other kind of molecule?
Proteins
What does the protein dynactin play a role in?
Cell differentiation
What is the name of a protein which plays a role in cell differentiation?
Dynactin
Type I lissencephaly is characterised by a reduction in the number of cortical layers. How many cortical layers should there be in a healthy individual versus someone with lissencephaly?
Six in a healthy person, three or four in someone with lissencephaly
Aside from a reduction in the number of cortical layers, what are the two other characteristics of lissencephaly?
- A thicker cortex than normal
- Reduced cortical folding
In someone with lissencephaly, what is the thickness of their cortex versus a healthy person’s?
10-20mm instead of usually 4mm
What is the branch of abnormal psychology focussed on?
The study of unusual or ‘abnormal’ patterns of behaviour or mental processes
When using the term ‘abnormal psychology’, what are we referring to?
Mental health conditions which can be diagnosed according to a formalised diagnostic categorisation system
Is the term ‘abnormal psychology’ actually useful?
Not really; there is not an ‘abnormal’ psychology which explains illness or distress and a ‘normal’ psychology for everything else - there is just psychology!
What is the name for the process by which the genetic code in DNA is converted to mRNA?
Transcription
In the context of DNA replication, what is Transcription?
The process by which DNA is converted to mRNA
In the context of DNA replication, what is Translation?
The process in which mRNA is converted to a chain of amino acids
What is the name for the process by which mRNA sequences are converted to chains of amino acids?
Translation
What is the first stage of DNA replication?
Transcription
What is the second stage of DNA replication?
Translation
What are the two types of RNA which are involved in the process of translation?
- rRNA
- tRNA
What does rRNA stand for?
Ribosomal RNA
What is ribosomal RNA (rRNA)?
A type of RNA that is a essential for protein synthesis
What is transfer RNA (tRNA)?
tRNA carries amino acids to the ribosome for protein synthesis
How many chromosomes does each human cell have?
46
What does phenotype mean?
The expression of physical or behavioural traits due to a particular gene
What are two other terms that mean “different versions of the same gene”?
- Genetic variants
- Alleles
In the context of health conditions, what is meant by the term ‘sign’?
Something that can be observed or measured by someone other than the individual
In the context of health conditions, what is meant by the term ‘symptom’?
A feature only detectable by the individual
What does the study of epidemiology relate to?
The study of the distribution of disease or health conditions in different groups of people at different times
What can epidemiology provide information about?
The causes, prevention and control of disease
What does the term prevalence mean?
The overall number of cases of a disease or condition which exist within a given population at a specific point in time
What is meant by the term incidence?
The number of new cases of a disease or condition in the given population within a certain time period
How can both incidence and prevalence be calculated?
As both absolute numbers or percentages
What kind of data does a cross-sectional study collect?
Information at a particular point in time
What makes cross-sectional studies useful?
It enables comparison of different groups of participants
What is a longitudinal study?
One which collects data by following participants over a set time period
What makes a longitudinal study useful?
It provides information about any changes that occur to particular groups of individuals over time
What is an experimental study?
A study in which only one variable (the independent variable) is changed in order to measure the effects on another variable (the dependent variable)
What is meant by the term independent variable?
A variable which is changed in order to measure the effects on another variable
What is meant by the term dependent variable?
The variable that is affected by the changes to the independent variable
What type of environment is an experimental study usually conducted in?
Fairly regulated and controlled conditions
What type of environment is an observational study usually conducted in?
More natural settings, without researcher manipulation, so that changes in behaviour can be observed
Do neurons and glial cells need the same type of proteins to function?
No
Why do glial cells and neurons require different proteins in order to function?
Because they perform different roles within the nervous system
What type of neurotransmitter does a cortical projection neuron require?
Glutamate
What type of neurotransmitter does a cortical interneuron require?
GABA (gamma amino butyric acid)
What is an interneuron?
A type of neuron that connects and modulates the activity of neurons within a limited region of the brain
What is meant by the term gene silencing?
It is the process by which the expression of a gene is suppressed
What is the name for the process by which gene expression is suppressed?
Gene silencing
What is meant by the term gene activation?
It is the process by which an expression of a gene is activated
What is the name for the process by which the expression of a gene is activated?
Gene activation
What are epigenetic mechanisms?
They are means by which gene expression is altered by regulation from either gene silencing or gene activation
What is the term used to describe what the processes of gene silencing and gene activation are?
Epigenetic mechanisms
Are the changes that gene silencing and gene activation cause permanent or reversible?
Reversible
Do the changes that gene silencing and gene activation bring about cause any effect to the genetic sequence coded in DNA?
No
What is the name for the proteins which the DNA sequence in a chromosome is coiled around?
Histones
What are histones?
The proteins in which the DNA sequence in a chromosome are coiled around
What does the coiling of the DNA sequence around histones produce?
A thread of DNA and protein called chromatin
What is chromatin?
A complex of DNA and proteins which organise genetic material within a cell’s nucleus
What is the name for the section of DNA which is coiled round a histone?
A nucleosome
What is nucleosome?
DNA which is wound around histone proteins and forms the basic unit of chromatin structure
What type of chemical group modifies the part of the histone which protrudes from the nucleosome?
Acetyl (COCH3) groups
What is DNA methylation?
It is a biological process by which methyl groups are added to DNA in order to regulate gene activity
How does DNA methylation work?
It adds chemical tags (methyl groups) to DNA
How do methyl groups switch gene expression on or off?
By increasing or decreasing gene transcription
What is histone acetylation?
A process which adds acetyl groups to histone proteins to affect gene expression
How does histone acetylation work?
It adds acetyl groups to histone proteins in order to modify chromatin structure
What does an increase in DNA methylation cause?
An decrease in transcription
What does an increase in histone acetylation cause?
An increase in DNA transcription
What are the two processes that determine which genes are accessible for transcription?
- Methylation
- Acetylation
The processes of methylation and acetylation are generally responsible for what?
Determining which genes are accessible for transcription
What is non-coding RNA?
It is RNA that does not carry genetic code after transcription
What is the purpose of RNA?
To regulate genes, influence cell function and play a vital role in cellular processes
Is non-coding RNA translated into a protein?
No
What is one type of non-coding RNA?
microRNA or miRNA
What is microRNA or miRNA?
A type of RNA which binds to mRNA causing cleavage, degradation or blocking of the translation process
What is the purpose of microRNA/miRNA?
To bind to mRNA and cause cleavage, degradation or blocking of the translation process
What type of structure does acetylation alter?
Chromatin structure
How does acetylation alter chromatin structure?
By modifying histone proteins, influencing gene expression and cellular functions in eukaryotic cells
What are eukaryotic cells?
Cells which house genetic material and enable complex functions through specialised compartments and organelles
Alteration of the chromatin structure is important for what reason?
To maintain renewal of embryonic stem cells
Explain why a methylation modification pattern is important for maintaining renewal of embryonic stem cells?
Because one particular pattern might keep embryonic stem cells dividing symmetrically and prevent asymmentric division. If that pattern changes it could then trigger asymmetric division
If maternal diabetes is not controlled, what chemicial can the extended period of hyperglycema cause an increase of?
Acetyl co-enzyme A (acetyl-CoA)
What process does the chemical acetyl-CoA play a very important role in?
Epigenetic regulation
What is glycolysis?
The process by which complex carbohydrates and simple sugars from food and drink are broken down during digestion
During glycolysis, what substances is the glucose then broken down into?
- Pyruvate
- Adenosine Triphosphate (ATP)
Which product of glycolysis goes on to be converted into acetyl-CoA?
Pyruvate
What do mitochondria use in order to produce more ATP?
Acetyl-CoA
What is the TCA cycle?
The series of chemical reactions that release stored energy
What does the addition of acetyl groups to chromatin affect?
DNA, during transcription
What is the name of the technique used to assess protein levels?
Western blotting
Western blotting is the name of the technique used for measuring what?
Protein levels
What are the three ways microRNA has a role in epigenetic regulation?
- It can cause cleavage of mRNA
- Degredation of mRNA
- Block the translation process
Which type of RNA is involved in epigenetic regulation?
microRNA
In mice with induced diabetes, embryonic stem cells had what notable change?
Altered chromatin structure
A change in chromatin structure is associated with an increase in what?
Acetylation
What is Dcx?
A protein called doublecortin
What is doublecortin (Dcx)?
A protein which is critical for neuronal migration and shaping the brain’s architecture during development
Name a protein which is critical to neuronal cell migration?
Doublecortin (Dcx)
Which protein, involved in cell migration, has also been found in a non-functional state in certain cases of lissencephaly?
Doublecortin (Dcx)
What protein is responsible for shaping the brain’s architecture during development, as well as being critical in neuronal migration?
Doublecortin (Dcx)
If microRNAs that target the translation of mRNAs from the DCx and PAFAH1B 1 genes are reduced, would levels of Dcx and PAFAH 1B 1 increase or decrease - and why?
They would increase.
MicroRNAs interfere with translation - if levels of microRNAs are reduced, their effect would be correspondingly reduced, which would mean the amount of protein produced would increase
An increase in levels of DCx and PAFAH 1B 1 would have what effect on microRNA?
It would decrease
The production of which proteins is reduced in lissencephaly?
- Dcx (doublecortin)
- PAFAH 1B 1 (platelet-activating factor acetylhydrolase 1B subunit alpha)
Along with being involved in neurogenesis and neuronal migration, PAFAH 1B 1 plays an important role in the regulating of what motor protein?
Dynein
What is Dynein?
A motor protein
What is meant by the term face validity?
The extent to which a test appears to measure what it is intended to measure
What is meant by the term construct validity?
The extent to which a test measures the psychological construct of interest
What is meant by the term content validity?
The extent to which a measure is representative of the aspects of what it is trying to measure
In a psychological context, what is meant by the term domain?
A specific aspect of functioning
In the field of psychology, what are the five domains?
- Social
- Emotional
- Cognitive
- Language
- Physical
What is maternal alpha fetoprotein (MAPF)?
A protein made by the fetus’ liver which can be used to test for the presence of spina bifida during the second trimester
Is MAPF (maternal alpha fetoprotein) present in all pregnancies?
Yes - but at a much higher level in fetus’ with neural tube defects
As well as spina bifida, what other congenital condition can be tested for by checking MAPF (maternal alpha fetoprotein) levels?
Down syndrome
