Op De Beeck
Neurologie
Dingen die hij niet zei in de les maar wel in te kennen pagina’s staan -> in klein
Les 1: The lesioned and stimulated brain (HF1 + 5)
CH1: LESIONED BRAIN
Mind and brain: empirical example
- Penfield: brain surgery to cure epilepsy
▪ Electrically stimulation parts of the brain (brain regions still intact?) -> fascinating experiences
▪ Not painful
▪ Electrical stimulating brain -> relive experiences (more real than just memories)
▪ Different areas -> different experiences
- Cognition: higher mental processes (thinking, speaking, acting, planning)
- Cognitive neuroscience: provides a brain-based account of cognitive and behavioural processes (perceiving,
remembering,..)
▪ Made possible by technological advances (safer, less crude)
Cognitive neuroscience in historical perspective
Philosophical approaches to mind and brain
- Mental experiences arise from…
▪ Heart: Aristoteles (heart is centre of the soul, brain is organ that cools the blood)
▪ Brain: Plato
- Mind-body problem: how can a physical substance (brain/body) give rise to a mental experience
▪ Dualism: mind and body separate substances (Descartes)
. Mind: non-physical, immortal
. Body: physical, mortal
. Interaction: pineal gland
▪ Dual-aspect theory: mind and body are two levels of explanation of the same thing (Spinoza)
▪ Reductionism: mind eventually explained solely in terms of biological/physical theory (Churchland)
. Ex: emotions can be explained in terms of neural firing
. Ex: phlogiston
‘Flammable’ component in a substance
In reality: chemical reaction with oxygen
Scientific approaches to mind and brain
- Aristoteles: ratio brain size-body size -> greatest in intellectual species
▪ How larger the intellect how lager the brain (cooling element)
▪ Ventricles are important
- Before 18th century: cortex drawn schematically or misinterpreted like intestines
- Gall & Spurzheim (1810): accurate depiction of the features of the brain (phrenology)
- Phrenology
▪ 1. Functional specialization: different parts of cortex have different functions (only this was correct)
. Functions they were talking about were different (ex: love for animals)
▪ 2. Differences in personality traits -> differences in cortical size and bumps on skull
. Crude division of psychological traits (ex: love)
- Modern cognitive neuroscience uses empirical neuroscience methods to ascertain different cognitive functions
▪ Does not assume that every region has 1 function
▪ Does not assume that every function has 1 region
▪ Does assume some degree of functional specialisation
- Functional specialisation
▪ Broca: patients with brain damage -> couldn’t speak, no further cognitive defaults
. Language is in 1 part of the brain
1
,Op De Beeck
. Specific fallout in function
▪ Wernicke: patient with bad comprehension & good production
. At least 2 language faculties in the brain that can be independently affected by damage
. Inference can be made without knowing where in the brain they are located
Cognitive neuropsychology
▪ Cognitive neuropsychology: study of brain damaged patients to inform theories of normal cognition
- Maps of the brain – Broadmann area
▪ 17: primary visual cortex
▪ 4: primary motor cortex
▪ 1,2,3: primary somatosensory cortex
▪ Functions
. Blue: motor cortex
. Purple: visual cortex
. Grey: outer cortex
▪ Deeper in the cortex -> executive functions
COMPUTER METAPHOR
- Computer metaphor: minds without brains
▪ 20th century: observations of behaviour, not observation of the brain during behaviour
. Models of cognition without direct reference to the brain
. Does not mean dualism! Was just practical
▪ Information-processing models (1950)
. Mind as a series of routines, like those found in computers
. Perception -> attention -> memory
▪ Connectionist models: mathematical (computational) in nature but don’t
involve serial processing and discrete routines
- Theory of modularity – (Fodor): certain processes are restricted in the type of information they process
▪ 1. Modules: domain specificity, only process certain type of information (shape, colour, faces,…)
▪ 2. Central systems: domain independent, non-specific information (memory, attention,…)
▪ Advantage: fast, efficient, in isolation from other systems
▪ Criticism: only means of acquiring is domain specific, systems are not innate
. Ex: reading can’t be innate, is new in evolution
- Computer metaphor/modules plausible?
▪ Interactivity: later stages of processing can begin before earlier stages are complete
▪ Top down: later stages influence earlier stages (memory influences perception)
▪ Bottom up: passage of info from simpler to more complex
▪ Parallel processing: different information is processed at the same time
The birth of cognitive neuroscience
- 1970: structural imaging methods (CT, MRI): precise images of brain/brain legions
- 1980: PET adapted to models of cognition developed by psychologists
- 1985: TMS first used (equivalent of Penfield)
- 1990: fMRI principle: level of oxygen in blood used as a measure of cognitive function
- Technology -> functional imaging + precisely describing brain lesions
- Stimulation
▪ Past: direct stimulation to brain (Parkinson)
▪ Now: transcranial stimulation across the skull
. TMS: transcranial magnetic stimulation
. tES: transcranial electrical stimulation
- Electrical/magnetic: changes in electric and magnetic properties of the cell
- Functional imaging (PET, fMRI, fNIRS): changes in blood supply
- Temporal resolution: when an event is occurring
▪ EEG, MEG, TMS, single cell -> resolution in milliseconds
▪ fMRI -> resolution in seconds
2
, Op De Beeck
- Spatial resolution: where an event is occurring
▪ Functional imaging & lesions -> millimetres
▪ Single cell -> at level of neurons
- Invasiveness: internal or external
▪ Internal: good spatial and temporal resolution
Method Type Invasiveness Brain property
EEG/ERP Recording Non-invasive Electrical
Single cell/multi-unit recording Recording Invasive Electrical
TMS Stimulation Non-invasive Electromagnetic
tES Stimulation Non-invasive Electrical
MEG Recording Non-invasive Magnetic
PET Recording Invasive Hemodynamic
fMRI Recording Non-invasive Hemodynamic
fNIRS Recording Non-invasive Hemodynamic
CH5: STIMULATED BRAIN
- Here: causal method’s
- Patient clip – alien hand
▪ Woman has no control over 1 arm, arm doesn’t listen to her
▪ Problem with corpus callosum -> signals don’t get through to the other side
▪ Doesn’t always go away, hard to treat
. U should keep the hand busy
- Classical cases
▪ Tan: language
▪ Phineas Cage: personality
▪ HM: memory
▪ DF: object recognition
- Reverse engineering: infer the function of a region by removing it and measuring the effect of the rest of the -
system (what can(‘t) the person still do)
- Disruption of brain functions come about through…
▪ Natural damage: stroke, trauma
▪ Elicited damage: animal models
▪ Harmless temporary changes induced electro-magnetically: TMS
Brain manipulation models
- Non-invasive brain stimulation (NBIS)
▪ Green in picture (non-invasive)
▪ TMS: magnetic stimulation -> producing virtual/reversible lesions
▪ tES: temporarily disrupting cognitive function OR boosting cognition
Ways of acquiring brain damage
- Neurosurgery
▪ Removing source of epilepsy
. Patient HM: amnesia after removing piece of medial temporal lobe
Amygdala + hippocampus taken away
▪ Split brain: sever fibers of corpus callosum (reduce spreading of seizures)
. Not much impairment in daily life, can be seen in experimental conditions
- Strokes (cerebrovascular accident - CVA)
▪ CVA: accident in the arteries (vascular) of the brain (cerebro), disruption of blood supply to brain
. Global or local death of neurons
▪ Very common
. 15% will not survive
. 50% will have long-lasting impairments
3
, Op De Beeck
▪ 2 types
. Ischemic infarction (80%, beroerte/herseninfarct)
Vessel blocked by fatty clot
Embolism: clot pushed from larger vessel to smaller
Thrombosis: stationary clot blocks vessel
Middle cerebral artery (80%)
Posterioir cerebral artery (5-10%)
Antererioir cerebral artery (0.6-3%)
. Haemorrhage/bleeding (20%, hersenbloeding)
Blood vessel ruptures
Increases intracranial pressure
More susceptible: born with aneurysms
Aneurysm: over-elastic region of artery -> ruptures more easily
▪ Angiomas: tangled blood vessels liable to rupture
▪ Arteriosclerosis: hardening of vessel walls
- Traumatic brain injury
▪ Most common in 0-40, more in men
▪ Coup: site of impact
▪ Contrecoup: brain pushed against skull
▪ Open injury: fractured skull, localized
▪ Closed injury: wide effects, loss of consciousness
. Diffuse axonal injury: damage/rupture between cell body and axon
- Tumours
▪ 2nd most common site for tumours (after uterus)
▪ Often metastatic
▪ Tumour: mass of new tissue that persists and grows independently
▪ Classification
. Benign vs malign
. Encapsuled vs infiltrating
. Primary vs secondary
. Cell types: meninges vs glia
Meningioma vs glioblastoma
▪ Puts pressure on neurons -> disrupt functioning, leading to cell death
- Viral infections
▪ Invasion of the body by disease-producing microorganisms & subsequent tissue reactions
▪ How do infections kill neural cells
. Interference with blood supply
. Disturb glucose or oxygen metabolism
. Alter cell membranes
. Form pus
. Cause edema
▪ Mostly widespread brain damage
▪ Ex: HSE (herpes simplex encephalitis), HIV, CJD (Creutzfeldt Jakob disease)
- Neurodegenerative disorders (zie foto’s op slides)
▪ Increasing impairments in one or more cognitive functions
▪ Atrophy of cells in brain -> memory loss
▪ Different types
. Alzheimer
. Frontotemporal dementia (Pick’s disease) -> very localized
. Huntington
. Parkinson
. Multi-infarct (vascular) dementia -> common
4
Neurologie
Dingen die hij niet zei in de les maar wel in te kennen pagina’s staan -> in klein
Les 1: The lesioned and stimulated brain (HF1 + 5)
CH1: LESIONED BRAIN
Mind and brain: empirical example
- Penfield: brain surgery to cure epilepsy
▪ Electrically stimulation parts of the brain (brain regions still intact?) -> fascinating experiences
▪ Not painful
▪ Electrical stimulating brain -> relive experiences (more real than just memories)
▪ Different areas -> different experiences
- Cognition: higher mental processes (thinking, speaking, acting, planning)
- Cognitive neuroscience: provides a brain-based account of cognitive and behavioural processes (perceiving,
remembering,..)
▪ Made possible by technological advances (safer, less crude)
Cognitive neuroscience in historical perspective
Philosophical approaches to mind and brain
- Mental experiences arise from…
▪ Heart: Aristoteles (heart is centre of the soul, brain is organ that cools the blood)
▪ Brain: Plato
- Mind-body problem: how can a physical substance (brain/body) give rise to a mental experience
▪ Dualism: mind and body separate substances (Descartes)
. Mind: non-physical, immortal
. Body: physical, mortal
. Interaction: pineal gland
▪ Dual-aspect theory: mind and body are two levels of explanation of the same thing (Spinoza)
▪ Reductionism: mind eventually explained solely in terms of biological/physical theory (Churchland)
. Ex: emotions can be explained in terms of neural firing
. Ex: phlogiston
‘Flammable’ component in a substance
In reality: chemical reaction with oxygen
Scientific approaches to mind and brain
- Aristoteles: ratio brain size-body size -> greatest in intellectual species
▪ How larger the intellect how lager the brain (cooling element)
▪ Ventricles are important
- Before 18th century: cortex drawn schematically or misinterpreted like intestines
- Gall & Spurzheim (1810): accurate depiction of the features of the brain (phrenology)
- Phrenology
▪ 1. Functional specialization: different parts of cortex have different functions (only this was correct)
. Functions they were talking about were different (ex: love for animals)
▪ 2. Differences in personality traits -> differences in cortical size and bumps on skull
. Crude division of psychological traits (ex: love)
- Modern cognitive neuroscience uses empirical neuroscience methods to ascertain different cognitive functions
▪ Does not assume that every region has 1 function
▪ Does not assume that every function has 1 region
▪ Does assume some degree of functional specialisation
- Functional specialisation
▪ Broca: patients with brain damage -> couldn’t speak, no further cognitive defaults
. Language is in 1 part of the brain
1
,Op De Beeck
. Specific fallout in function
▪ Wernicke: patient with bad comprehension & good production
. At least 2 language faculties in the brain that can be independently affected by damage
. Inference can be made without knowing where in the brain they are located
Cognitive neuropsychology
▪ Cognitive neuropsychology: study of brain damaged patients to inform theories of normal cognition
- Maps of the brain – Broadmann area
▪ 17: primary visual cortex
▪ 4: primary motor cortex
▪ 1,2,3: primary somatosensory cortex
▪ Functions
. Blue: motor cortex
. Purple: visual cortex
. Grey: outer cortex
▪ Deeper in the cortex -> executive functions
COMPUTER METAPHOR
- Computer metaphor: minds without brains
▪ 20th century: observations of behaviour, not observation of the brain during behaviour
. Models of cognition without direct reference to the brain
. Does not mean dualism! Was just practical
▪ Information-processing models (1950)
. Mind as a series of routines, like those found in computers
. Perception -> attention -> memory
▪ Connectionist models: mathematical (computational) in nature but don’t
involve serial processing and discrete routines
- Theory of modularity – (Fodor): certain processes are restricted in the type of information they process
▪ 1. Modules: domain specificity, only process certain type of information (shape, colour, faces,…)
▪ 2. Central systems: domain independent, non-specific information (memory, attention,…)
▪ Advantage: fast, efficient, in isolation from other systems
▪ Criticism: only means of acquiring is domain specific, systems are not innate
. Ex: reading can’t be innate, is new in evolution
- Computer metaphor/modules plausible?
▪ Interactivity: later stages of processing can begin before earlier stages are complete
▪ Top down: later stages influence earlier stages (memory influences perception)
▪ Bottom up: passage of info from simpler to more complex
▪ Parallel processing: different information is processed at the same time
The birth of cognitive neuroscience
- 1970: structural imaging methods (CT, MRI): precise images of brain/brain legions
- 1980: PET adapted to models of cognition developed by psychologists
- 1985: TMS first used (equivalent of Penfield)
- 1990: fMRI principle: level of oxygen in blood used as a measure of cognitive function
- Technology -> functional imaging + precisely describing brain lesions
- Stimulation
▪ Past: direct stimulation to brain (Parkinson)
▪ Now: transcranial stimulation across the skull
. TMS: transcranial magnetic stimulation
. tES: transcranial electrical stimulation
- Electrical/magnetic: changes in electric and magnetic properties of the cell
- Functional imaging (PET, fMRI, fNIRS): changes in blood supply
- Temporal resolution: when an event is occurring
▪ EEG, MEG, TMS, single cell -> resolution in milliseconds
▪ fMRI -> resolution in seconds
2
, Op De Beeck
- Spatial resolution: where an event is occurring
▪ Functional imaging & lesions -> millimetres
▪ Single cell -> at level of neurons
- Invasiveness: internal or external
▪ Internal: good spatial and temporal resolution
Method Type Invasiveness Brain property
EEG/ERP Recording Non-invasive Electrical
Single cell/multi-unit recording Recording Invasive Electrical
TMS Stimulation Non-invasive Electromagnetic
tES Stimulation Non-invasive Electrical
MEG Recording Non-invasive Magnetic
PET Recording Invasive Hemodynamic
fMRI Recording Non-invasive Hemodynamic
fNIRS Recording Non-invasive Hemodynamic
CH5: STIMULATED BRAIN
- Here: causal method’s
- Patient clip – alien hand
▪ Woman has no control over 1 arm, arm doesn’t listen to her
▪ Problem with corpus callosum -> signals don’t get through to the other side
▪ Doesn’t always go away, hard to treat
. U should keep the hand busy
- Classical cases
▪ Tan: language
▪ Phineas Cage: personality
▪ HM: memory
▪ DF: object recognition
- Reverse engineering: infer the function of a region by removing it and measuring the effect of the rest of the -
system (what can(‘t) the person still do)
- Disruption of brain functions come about through…
▪ Natural damage: stroke, trauma
▪ Elicited damage: animal models
▪ Harmless temporary changes induced electro-magnetically: TMS
Brain manipulation models
- Non-invasive brain stimulation (NBIS)
▪ Green in picture (non-invasive)
▪ TMS: magnetic stimulation -> producing virtual/reversible lesions
▪ tES: temporarily disrupting cognitive function OR boosting cognition
Ways of acquiring brain damage
- Neurosurgery
▪ Removing source of epilepsy
. Patient HM: amnesia after removing piece of medial temporal lobe
Amygdala + hippocampus taken away
▪ Split brain: sever fibers of corpus callosum (reduce spreading of seizures)
. Not much impairment in daily life, can be seen in experimental conditions
- Strokes (cerebrovascular accident - CVA)
▪ CVA: accident in the arteries (vascular) of the brain (cerebro), disruption of blood supply to brain
. Global or local death of neurons
▪ Very common
. 15% will not survive
. 50% will have long-lasting impairments
3
, Op De Beeck
▪ 2 types
. Ischemic infarction (80%, beroerte/herseninfarct)
Vessel blocked by fatty clot
Embolism: clot pushed from larger vessel to smaller
Thrombosis: stationary clot blocks vessel
Middle cerebral artery (80%)
Posterioir cerebral artery (5-10%)
Antererioir cerebral artery (0.6-3%)
. Haemorrhage/bleeding (20%, hersenbloeding)
Blood vessel ruptures
Increases intracranial pressure
More susceptible: born with aneurysms
Aneurysm: over-elastic region of artery -> ruptures more easily
▪ Angiomas: tangled blood vessels liable to rupture
▪ Arteriosclerosis: hardening of vessel walls
- Traumatic brain injury
▪ Most common in 0-40, more in men
▪ Coup: site of impact
▪ Contrecoup: brain pushed against skull
▪ Open injury: fractured skull, localized
▪ Closed injury: wide effects, loss of consciousness
. Diffuse axonal injury: damage/rupture between cell body and axon
- Tumours
▪ 2nd most common site for tumours (after uterus)
▪ Often metastatic
▪ Tumour: mass of new tissue that persists and grows independently
▪ Classification
. Benign vs malign
. Encapsuled vs infiltrating
. Primary vs secondary
. Cell types: meninges vs glia
Meningioma vs glioblastoma
▪ Puts pressure on neurons -> disrupt functioning, leading to cell death
- Viral infections
▪ Invasion of the body by disease-producing microorganisms & subsequent tissue reactions
▪ How do infections kill neural cells
. Interference with blood supply
. Disturb glucose or oxygen metabolism
. Alter cell membranes
. Form pus
. Cause edema
▪ Mostly widespread brain damage
▪ Ex: HSE (herpes simplex encephalitis), HIV, CJD (Creutzfeldt Jakob disease)
- Neurodegenerative disorders (zie foto’s op slides)
▪ Increasing impairments in one or more cognitive functions
▪ Atrophy of cells in brain -> memory loss
▪ Different types
. Alzheimer
. Frontotemporal dementia (Pick’s disease) -> very localized
. Huntington
. Parkinson
. Multi-infarct (vascular) dementia -> common
4
