Neuroscientific Approach to Language (Class 1) PDF

Language and cognition October 3rd 2024 The students know the main techniques used within the neuroscientific approach to studying language and the brain, as well as their advantages and disadvantages, including spatial and temporal resolution The students are aware of recent insights into langu...

Language and cognition October 3rd 2024 The students know the main techniques used within the neuroscientific approach to studying language and the brain, as well as their advantages and disadvantages, including spatial and temporal resolution The students are aware of recent insights into language and the brain based on the neuroscientific approach, and they can estimate to what extent these insights differ from knowledge based on the other approaches The students understand the strengths and weaknesses of the neuroscience approach Approach #3 The neuroscientific approach  Structure Introduction 4 main approaches in the study of language and the brain Psycholinguistics - the study of language processes through experiments Neurolinguistics - the study of language processes in patients Neuroscience of language - the study of language processes in the brain Computational (psycho)linguistics - the creation of computer models to better understand language processes  Structure How does this approach proceed? Many similarities to psycholinguistics: Cognitive task (stimuli ans responses) Theory (although!) Healthy subjects (but also patients) But also differences: Complex techniques to measure brain activity Complexe statistics to process images The students know the main techniques used within the neuroscientific approach to studying language and the brain, as well as their advantages and disadvantages, including spatial and temporal resolution The students are aware of recent insights into language and the brain based on the neuroscientific approach, and they can estimate to what extent these insights differ from knowledge based on the other approaches The students understand the strengths and weaknesses of the neuroscience approach Based on which two main parameters can techniques for studying brain activity be divided?  Neuroscience of language How do the following techniques to study the brain compare on these two key parameters: single unit recording, ERP, PET, MRI, MEG, TMS, tDCS?  Neuroscience of language What is the main limitation of single-unit recording?  Neuroscience of language Single-unit recording micro-electrodes 1 mm / 110.000 control of individual nerve cells invasive and rarely used  Neuroscience of language EEG 13  Neuroscience of language  Neuroscience of language EEG Excelent temporal resolution 15  Neuroscience of language  Neurolinguïstiek EEG/ERP + good temporal resolution - Bad spatial resolution (image of skull and brain are distorted) - Only for simple processes  Neuroscience of language PET = positron emission tomografie Advantages Good spatial resolution (where – 5-10 mm) Disadvantages Very bad temporal resolution (when – 30 - 60 sec.) Indirect measure Invasive (radioactive substance)  Neuroscience of language  Neuroscience of language fMRI Magnetic resonance imaging is used to gather information about the localisation (where?) of internal cognitive processes in the brain BOLD : blood-oxygen level-dependent contrast. Brain activity requires oxygenated blood, which has specific magnetic properties the scanner can capture 21  Wagner et al. 1998 What are some limitations of fMRI?  Neuroscience of language 1. Bad temporal resolution 2. Still a relatively indirect measure 3. Brain signal is superimposed on structural brain templates of an average brain, so little room for individual variation 4. Limitations in terms of stimuli (both visual and auditory) What is the main limitation of MEG?  Neuroscience of language  Neuroscience of language Magnetoencephalography (MEG) - Expensive + Good (excellent) temporal and spatial resolution (often better than EEG, but worse than fMRI) What are the four main benefits of TMS?  Neuroscience of language TMS Transcranial magnetic stimulation coil administers short magnetic pulse (1 ms) - temporary lesion crucial to know whether a particular region is necessary for a cognitive task  Neuroscience of language TMS Transcranial magnetic stimulation Advantages 1. Causal relations – similar to neurolinguistics 2. More flexible because comparison with and without injury – different from neurolinguistics 3. More flexible because researcher determines where the lesion is administered - different from neurolinguistics 4. Provides information when a brain region is active - different from neurolinguistics What are four limitations of TMS?  Neuroscience of language TMS Transcranial magnetic stimulation Disadvantages 1. Effects are complex and not always well understood - sometimes improving behaviour through compensation! - Link with theoretical positions of neurolinguistics 2. Not sure exactly which brain region is affected due to connections between remote brain regions 3. Limited in terms of locations use 4. Small risks What are some advantages of using tDCS compared to TMS?  Neuroscience of language  Neuroscience of language  Neuroscience of language Advantages 1. Anodal tDCS improves cognitive functioning > therapy 2. Few risks  Structure How does this approach work? What has this approach taught us about language and the brain? What are advantages and disadvantages of this approach? The students know the main techniques used within the neuroscientific approach to studying language and the brain, as well as their advantages and disadvantages, including spatial and temporal resolution The students are aware of recent insights into language and the brain based on the neuroscientific approach, and they can estimate to what extent these insights differ from knowledge based on the other approaches The students understand the strengths and weaknesses of the neuroscience approach  Neuroscience of language The brain, complex matter Consider the assumptions of neurolinguistics! +- 100 billion neurons Each neuron can connect with 10,000 other neurons  Neuroscience of language Brain = central nervous system. It is made up of three parts: Cerebrum ('big brain') Cerebellum ('cerebellum') Brain stem 40  Neuroscience of language The cerebrum and cerebellum consist of a left and a right hemisphere. Cerebrum ('big brain') Cerebral cortex left cortex right cortex Limbic system left limbic system right limbic system Basal ganglia left basal ganglia right basal ganglia Cerebellum ('little brain') left cerebellum right cerebellum Brain stem  Neuroscience of language The left and right hemispheres of the cerebellum and cerebellum are symmetrical, mirror images of each other. Any structure we find in the left hemisphere, we also find in the right hemisphere. However, this is not perfect symmetry. In every individual, small asymmetries can occur between the two hemispheres of the brain. Eg. Facial asymmetry, limb asymmetry, etc.  Neuroscience of language  Neuroscience of language Humans have a larger brain volume than you would expect based on weight. What different ways exist to describe brain parts?  Neuroscience of language Dorsal >< ventral Anterior >< posterior Lateral >< medial Brodmann areas Why is it important to gain insight into how the brain is connected?  Neuroscience of language 1. Better understanding of the brain 2. Functioning of the brain is strongly linked to structural connections 3. Individual differences in functioning often reflect individual differences in connections Which two principles apply to the organisation of complex systems and how can this be applied to the human brain?  Neuroscience of language Principle of cost control Maximum number of short-distance connections Principle of efficiency Maximum number of long-distance connections  Neuroscience of language  Neuroscience of language Trade-off between cost control and efficiency A number of modules or small areas with densely clustered (short-distance) connections A number of hubs or areas with large numbers of (long-distance) connections to other areas Does this remind you of anything? The students know the main techniques used within the neuroscientific approach to studying language and the brain, as well as their advantages and disadvantages, including spatial and temporal resolution The students are aware of recent insights into language and the brain based on the neuroscientific approach, and they can estimate to what extent these insights differ from knowledge based on the other approaches The students understand the strengths and weaknesses of the neuroscience approach What are four strengths of the cognitive neuroscientific approach of language?  Neuroscience of language Voordelen 1. Empirical verification of theoretical controversies 2. Complexity of cognitive systems mapped 3. Already >10,000 fMRI studies published 4. Re-analysis of previously obtained data based on new insights What are nine limitations of the cognitive neuro(language) science approach?  Neuroscience of language Disadvantages 1. Problem of ecological validity and task specificity 2. Correlation, not causation 3. Overinterpretation of effects and reverse inference (involvement, not necessity) 4. Functioning of our brain more complex than the language we use to describe it 5. Testing of theories is rare, often exploratory 6. False positives due to many data points 7. Replication problems 8. Not always extra, but sometimes less activation, in cognitive processes (default mode network) 9. Neuroenchantment