PsychoBrain 31 st January 2018 Dr Christos Pliatsikas Lecturer in - - PowerPoint PPT Presentation

PsychoBrain

31st January 2018 Dr Christos Pliatsikas

Lecturer in Psycholinguistics in Bi-/Multilinguals University of Reading

By the end of today’s lecture you will understand

• Structure and function of the brain
• Methods used to study the brain

The Brain

• Grouping of nerve tissue within

the skull

• Weighs around 1.4kg
• Creates consciousness, judgment,

thought, memory and emotion

• Heads the nervous system that

allows our body to complete basic functions that keep us alive

What’s in your head?

Hemispheres of the Brain

Divided into 2 almost Identical Halves: Cerebral Hemispheres Covered by three membranes (meninges) a) Dura b) Arachnoid c) Pia

Hemispheres linked by two bundles of fibres (white matter):

• Corpus Callosum
• Anterior commissure

Some neuroanatomy

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http://users.tamuk.edu/kfjab02/Biology/AnimalPhysiology/B3408%20Systems/syst ems%20images/neuron.png.jpg http://www.medinewsdigest.com/wp-content/uploads/2011/12/Brain_Cortex_Harvard.png

• White matter (WM): The

collection of the brain’s axons

• Grey matter (GM): The

collection of the brain’s cell bodies

Organisation of the cerebral cortex

‘higher’ functions

The Senses

• Information from sensory organs received by:

– Primary visual cortex – Primary auditory cortex – Primary somatosensory cortex (taste, touch) – Gustatory (taste) and olfactory (smell) cortices – Associations between sense organs and cerebral cortex are ‘contralateral’

Control of movement

– Different parts of the primary motor cortex are connected to muscles in different parts of the body – Associations are contralateral too

Motor and sensory areas

Cortical specialisation and brain plasticity

• The functional specialisation of the cortex is not necessarily static
• The role of specific regions can be “reassigned”
• For example:
• Patients with stroke: Initial inability to speak (“aphasia”),

which improves with time and therapy. Why?

• Regions near the ones destroyed “take over” the

functions of speaking

• Congenitally blind people show activation of the occipital

cortex for tactile “Braille” reading

• An otherwise unused brain region takes over for a newly

acquired skill

Discuss

People use 10% of their brain

Myth!

Studying the brain

• Accidental damage – e.g. Phineas Gage
• Stroke, e.g. Broca’s & Wernicke’s regions
• Brain surgery
• Non-invasive recording techniques e.g.

EEG, fMRI

• Non-invasive neurostimulation, e.g. TMS

Lesion studies

• Initially the only available method to study

the functions (or lack of) of the brain.

– The “anatomo-clinical” method: Patient behaviour was observed and recorded, and linked to brain damage post-mortem.

• Paul Broca (1861):

– One of his patients had problems in speaking – Only simple syllables could be produced (“tan”) – Post-mortem analysis revealed extensive damage in a posterior area of the Left Inferior Frontal Gyrus (LIFG) – The area was named after Broca – It has been known to be crucial for speech production

Corpus callosotomy – severing corpus callosum ‘split-brain’ patients - information cannot be passed between hemispheres

Brain surgery

Visual-field studies

• Fixate on central point,

present stimulus to one visual field

• Information from left visual

field goes to right hemisphere and vice-versa

• In ‘split-brain’ patients,

information cannot pass between hemispheres

Image: http://wps.prenhall.com/hss_wade_mru_2/0,7992 ,823168-,00.html Accessed 6/11/5

Image: http://slideplayer.com/slide/8396581/ http://www.youtube.com/watch?v=lfGwsAdS9Dc

Discuss

• This visual illusion supposedly tells

you whether you are right or left brained: – http://www.youtube.com/wat ch?v=ilaHDcfA9Eg&feature=re lated – See if you can change the direction of the dancer

There are right- and left-brained people

Myth!

Non-invasive recording

• Measuring Electrical Activity: EEG: Electrodes attached to

the scalp and record electrical activity (action potentials from groups of neurons)

• Looking at the Whole Brain (Imaging): fMRI: Detecting

which particular brain areas are involved in particular types

• f processing
• Brain Stimulation: TMS: Potentials are triggered at specific

brain areas to define their function

Modern EEG recording Brain activity measured by electrical impulses is now recorded and analysed using computers

• Uses magnetism to build up a picture of

the inside of the body.

• 3D representation of the brain
• functional MRI (fMRI): Looking at

localisation of brain function in real time

– Brain activity as a response to specific stimuli – The more active the neurons become, the more blood is needed

• Pliatsikas et al.(2014a): Brain regions

activated for the processing of grammatically complex words

– E.g. played (play + ed)

Magnetic Resonance Imaging (MRI)

• Structural MRI: Looking at the brain’s structure

– Similar methods and identical equipment to fMRI – Looking at structural effects in the brain – Grey and white matter – Pliatsikas et al. (2014b): Cerebellar volume in non-native speakers correlates with how fast they are in a grammatical task.

Magnetic Resonance Imaging (MRI)

Transcranial magnetic stimulation (TMS)

Strong magnetic field creates electrical currents in the brain Can target cortical areas as small as 1 cm2 Those currents can cause or disrupt a function

• Visual: phosphenes
• Language: speech arrest

Discuss

There are male brains and female brains

http://www.helloquizzy.com/quizzy/take

Myth!

Thank you!

https://christoslab.wordpress.com/ @Christos_lab

https://www.facebook.com/bilingualisminthebrainlab/ c.pliatsikas@reading.ac.uk

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