brain imaging techniques

still pictures

single static images that are two dimensional

CT AND MRI

dynamic pictures

3D images that change in real time

• fMRI

Strucutral imaging

neuroimageing techniques that produce scans showing brain structure

• CT + MRI structural details such as tussye damage, brain atrophy, fluid filled spaces, bleeds, size and location in tumours

functional imaging

neuroimaging techniques producing scans showing brain function

• fMRI

temporal resolution

ability to detect when brain activitty occured

• greater ability to detect rapid changes = higher temp res

• (EEG, can show within milliseconds)

• high temp can indicate when the activation occured

spatial resolution

ability to differentiate which specific part of the brain is active

• eeg has high temp, low spat

• high spat res = fMRI, can pinpoint the location of neural activity with millimeter precision (low temp res)

EEG

electroencephalogram

• functional technique, shows brain activity in real time

how EEG works

electrodes placed on scalp

electrical activity (brain waves) detected then carried via wires to EEG recording machine where displayed

electrical changes within thousands of neurons detected at same time

uses

• diagnosing epilepsy

• sleep research

• which part being utilised during mental tasks

• confirmation of brain dead

strengths

high temp res (can detect rapid changes in brain waves)

safe and non-invasive

limitations

low spat res, (precise location of activity is not clear

• conducive gel increases temp res, decreases spat res as does scalp, skull, thick membrane

• messy due to conductive gel

CT

Computed Tomography

• structural neuroimaging technique

• produces still pictures

how it works

rotating x ray beam moves 360 around patient

takes multipe x ray images

computer pieces many 2d x rays and produces 3d reconstruction that tech can scroll through

uses

fractures in skull (better defines bone structures)

diagnose brain tumours + size of brain tumour

assess brain injury from trauma (bleeds, fluid filled spaces)

strengths

• patients with metals can have scan (such as aneurysm clips

• can image bone, soft tissue and blood vessels at same time

limitations

exposed to ionising radiation (increases risk of cancer later on)

not suitable for pregnant women as radiation can damage fetus

MRI

magnetic resonance imaging

structural that produces still pictures

how it works

strong magnetic field and radio waves

lines up the protons in hydrogen atoms then short bursts of radiowaves tip protons out of alignment

protons realign = release radio signals that are detected in scanner

different structures = different signals to be distinguished in pics

uses

• diagnose brain tumours

• measure size of brain tumour

• assess stroke effects

• asses brain injury from trauma

strenghts

more detailed than those formed in CT scans (can see soft tissues like brain tumours)
does not expose patient to ionising radiation (safer for pregnant women but not recommened during first trimester where organs are still forming)

limitations

cant have metal on body

loud banging noises and ear protection

fMRI

functional magnetic resonance imaging

• functional that produces dynamic pictures

how it works

strng magnetic field + radiowaves to show where neurons are consuming oxygen in the brain in real time

• scanner creates 3D map of brain broken up into volume blocks called voxels

• when neurons communicate with each other through electrical impulses and neurotransmitters, energy i sused.

• oxygen rushes to area through blood causeing voxel to change colour and becom ered, and voxel colour returns to normal once the blood stops rushing oxygen to active neyrons

• scanner detects colour change cos high oxy blood = more iron, more attracted to magnets

• difference in magnetism is shown as shades of light and dark called bold signal (blood oxygen level dependent signal)

• higher bold = < oxygen level in blood

uses

show part of the brain active when performing task

help plan for tumour removal surgrey (when patient asked to do tasks that causes changes to areas of brain responsible for speech, surgeon can map where area is an avoid it)

assess effects of stroke

brain activity of patients with neurological conditions

strenghts

high enough spat res to determine location of neural activity down to few cubic meters

does not expose to ionising ratiatio

limitations

no metal

temporal res lower than ct and eeg, meaning scans take longer to detect changes in enural activity because bold signal relies on body response to metabolic changes

takes about 2 seconds

adaptive plasticity

ability of neural connections to reorganise themselves in response to learning new information, compensate ofr lost function and take advantage of remain gfunctions

• brocas aphasia patient may have spontaneous speech function be diminished at dfirst, over the next few months his brain will experienced heightened plasticity

developmental plasticity

the ability of neural connections in the brain to reorganise in response to sensory input from the environment

• baby practicing motor skills

plasticity

the ability of neural connections to grow and reorganise

steps in plasticity

proliferation

migration

circuit formation

synaptic pruning

myelination

proliferation

growth and division of cells (e.g neurons) that leads to increase in cell number

• most are already formed, some are created during infancy

migration

newly generated neurons move throughout the brain until reaching their final position, allowing for connections between neurons to be made

• migrate via chemical traisl moved by other neurons

• moving along scaffoldding fibres in brain

ends at 5 motnhs

circuit formation

neurons make neural circuits with neurons by sending electrochemcal messages nbetween each other

• within clusters

• larger distances

develop rapidly in primary sensory and primary visual

synaptic pruning

infants born with more neurons than required, so ones that odnt form active connecitions with others just die

• increases efficiency by allowing remaining connections to strengthen and grow in complexity

myelination

myellin starts growing over axons of neurons, insualing neural connections and allowing faster and more efficient nerve impulse travel throughout brain

contributes to dramatic brain growth

begins in spinal cord, hindbrain, midbrain, forebrain , peripheral neervous system

amygdala during adolescence

amygdala: collection of nuclei deep within each. temporal lobe

plays a role in emoitonal response and immeidate behavioural reactions as response to emotion

• grows in volume (could be due to puberty)

• as PF still developing, so are connections between the to

• instead of PF leading actions based on rational and logical thinking, volatile amygdala guides automatic actions

• highly reactive to emotional stimuli, like facial expressions and stressful situations

• more likely to misinterpret things, and get into accidents and behave inappropriately

prefrontal cortex during adolescence

PFC: layer of frontal lobes just beneath forehead that continues to undergo myelination during adolescence to an increase in white matter

• synaptic pruning occurs during adolescence, reducing grey matter andf allowing increasign complex and efficienct connections to be made

• SP begins at back and ocmes forward with being the last to develop

• region responsible for problem solving, risk aassessment, attention and consequence prediction.

• allows understanding of why teens do not seem to assess potential risks + risky situations

attachment

strong emotional connection between an infant and their main attachment figure

theory of attachment time

1969, 1988

bowlby’s monotropic theory

children have biological need to form bond with one main attachemnt figure

most important bond

usually with mother

mother also has biological need to be close to them

monotropy

attachment with only one attachment figure

bowlby’s maternal deprivation hypothesis

theorised that the first 2 ½ years = critical for forming attachment with main attachment figure

failure to form connection = difficulty forming attachment later on

critical period

lifespan stage during whihc individuals are more sensivity to environmental influences and normal development relies on these particular life experiences occuring

maternal deprivation

consequences an individual experiences when they are seperated from mother/substitute as a child

attachment is prevented from occuring

• intellectual development may bee delayed, evident in abnormally low iq

• emotional development may be affected, especially empathy (aka affectionless psuchopath)

• difficulty forming social relationships (e.g intimate relationships later on)

internal working model

• how are they formed

• what is their impact

• why are they called internal working model

• what do they guide

• what does an accurate one lead to

• during daily interactions with primary caregivers during first few yeasr, children develop internal working models of primary caregivers/themselves/others

• impact they have on cognition, emotions, behaviour are outside of the childs concious awareness

• mental represenations and are called internal working models becaause they serve as template, model for wat relationships are like

• guide way

  • child responds

  • approach towards new relationships

  • emotional and social behaviour

• accurate internal working models of their immediate world = insight they need and will therefore be better prepared for interacting with wider society in real world when older

three internal working models

internal working model of others

internal working model of self

internal working model of relationship between self and others

internal working model of others

age of 5, children have learned great deal about caregivers and now have internal working model of likes, dislikes, characteristcs

internal working model of self

child creates positive internal working model where they believe they are worthy of love and comfort due to their caregivers

negative one is formed when caregivers consistently rrejected child and ignored needs, making them believe the oppostie

internal wokring model of relationship with self and others

child bases future relationships with other people on their first relationships with primary caregivers

• differ for varying caregivers (internal working model between relationship of child and mother but different with gma)

defines their expectations of furture relationships, unconcious expectations such as respect and reliability, demonstrates same qualities as attachment figure

evollutionary perspective of bowlby

prupose of attachment between human infant + main attachment figure was to

• protect from predators

• allow survival of species

supported thru observations of isolated birds + mammals that are more likely to be attacked by predator than others of same species

• attachment figure = who they believe will reliably and promptly come to aid when required

• failure of attachment fgirure to repsond causes extreme stress and tauma

strenghts

• research on attachment and maternal deprivation led to numerous orphan studies that allowed for improved conditions of those left in such institiudtions

• internal working model provides strong reasoning for relationships that adults form. clear to see how first attachments = produced template used for forming health relationships

limtations of theory

believed mother was primary caregiver, tho ajority of societies around world are observed to have multiple attachment figures invovled

evidence suggests that in many instances, high quality aftercare allowed indiviudals who failed to form attachemnt in firts 2 ½ years to fullt recover. critical should be called sensitive

critical = specific life instances to occur for normal development, sensitive = stages in life whereby effects that experiences have on brain are stronger than usual. normal development is still possible even if required life epxeriences do not occur during sensitive periods

application of theory to real world context

understandning of how maternal deprivation affects childs ability to develop can help inform social wworkers to provide education and resources to families in ordet to support them in providing healthy attachment figures for children

strange situation to measure attachment

1978

• ainsworth developed three types of attachment

• beleives that type of attachment relationship formed between mother and child depended on how sensitve and responsive the motehr ewas to child signals

aim

measure quality of attachment young chiildren had with main attachment figure

participants

100 one year old children and mothers

materials

chair and toys for children to play with

design

IV = mother and strangere leaving and entering the room

DV = observed behaviour of children

procedure

controlled by observational research

one year old chilldren exposed to seven episodes, same order, 3 minutes

researchers i nadjoining room observed child through one way mirror/cameras

recorded type and intensitiy of behaviour displayed in fifteen second intervals

tests

proximity seeking

exploration and secure base behaviour

stranger anxiety

seperation anxiety

response to reunion

proximity

whether infant stays in close proximity to mother

exploration + secure base behaviour

confidence to explore environment while using mother as secure base to return to

stranger anxiety

how anxious they were around stranger

seperation anxiety

anxious when seperated from mother

response to reunion

behaviour shown when baby reunited with mother

wwhat did the mother do

1) encouraged exploration

2) unfamiliar adult entered room, spoke to mother and approached

3) mother left room and baby was with stranger

4) mother returned, stranger left

5) mother left, baby is alone

6) stranger returned to room

7) mother returned to room

type A typical behaviour (insecure avoidant)

proximity seeking

• does not seek it

exploration and secure base behaviour

• happy to explore but doesnt return to mother

stranger anxiety

• shows very little anxiety

seperation anxiety

• no sign of distress when left alone by mother

response to reunion

• no interest in mother

• may avoid contact

type a mothers behaviour

mother ignores infant,

infant believes that communication of needs has no influence on mother

type B (secure attachment)

proximity seeking

• happy to seek proximity

exploration and secure base behaviour

• happy to expolore, uses mother as base

stranger anxiety

• moderate

seperation anxiety

• moderate

response to reunion

• happy, seeks comfort

type B behaviours

mother is sensitive to baby needs (responds to moods and feeling of infant correctyl)

type C (insecure resistant)

proximity seeking

• seeks great proximity

exploration and secure base behaviour

• very little

• does not sue mother as secure base

stranger anxiety

• high

seperation anxiety

• high

response to reunion

• approach mother, resists comfort

type c behaviours

mother is inconsistent with primary care,

sometimes ignores, sometimes meets needs

contributions to society

first empirical evidence to support bowlby’s attachment theory

(E.g secure attachment tend to hvae postive internal working models with self and others), and throughout life believe they are worthy of being lvoes and respected

insecure are more likely to develop poor ones

criticisms of study

• ainsworth claimed that study was moddled on real life experiences where infants would be taken to unfamiliar environments and left for a few minutes

• people disagree and said ti caused a degree of psychological harm

• may ionly be valid in western europe as USA ass it was developed i n these two locations.

• difficult to generalise findings to societies outside WE and USA

van ijzendoorn and kroonenberg (1988)

TYPE A: insecure avoidant = western european countries and USA than in china, japan and istral

TYPE B: most common across all countries

TYPE C: insecure resistance = more prevalent in japan and israel than any of fthe inclluded countries

enriched environment

described as social physical surroundings that facilitate intellectual and sensory stimulation

• believed to greatly impact early development of children during critical and sensitive periods because brain plasticity is particularly influenced by experience

deprived environment

abscence of ocnditions that stimulatethe senses and allow for intellectual growth

lack of exposure ot learning environments reduces cognitive development and poor social skills

genie the wild child 1957

• father disliked her, prevented mother from giving attnetion

• doctors said she showed possible sides of retardation. isolated her by confining her to small room

• harnessed to potty seat, sat there naked during day and placed in sleepign bag with arms restratined at night

• heard very little language and father disliked noise so learned to keep quiet because he beat her

• at 13 years old, genie and mother moved away from father, social worker calle dpolice who charged parents and admitted genie tho hsopital

• had weak vocal cords, weak muslces for chewing and swlalowing, could not stand up stragiht or extend limbs

• did not allow her to develop language, could only say a few words adn even those words were hard to comprehend. keen for attention and contact in hospital

• moved to rehab centre and then foster home which were enriched enviromenta that helped her develop socially, emotionally, physically and cognitively.

  • grew taller

  • put on weight

  • walk with steady gait

  • developed close relationships

  • emoitonally appropriate responses

  • improvemenrts in.cognitive awareness nad functioning

  • vocab grew quickly

  • not able to use grammar or speak infulls entecnes

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