Neuropsychology & psychopharmacology – januari 2025 1
NEUROPSYCHOLOGY
COGNITIVE NEUROSCIENCE
= aims to provide a brain-based account of cognitive and behavioral processes (perceiving, remembering …)
- This is made possible by technological advances in the studying of the brain
THE MIND-BODY PROBLEM
The ancient Greeks were already discussing where mental experiences come from, e.g. Aristotle assumed it
came from the heart, while Plato thought it was the brain
The mind-body problem: how can a physical substance (brain and/or body) give rise to mental experience?
• There were different philosophical and scientific approaches to this
PHILOSOPHICAL APPROACHES TO MIND AND BRAIN
- Dualism: the mind and body are separate substances, and there are specific structures in the body (like the
pineal gland) that are responsible for the interaction between the two (e.g. Descartes)
- Dual-aspect theory: the mind and body are two levels of explanation of the same thing (e.g. Spinoza)
- Reductionism: the mind is explained solely in terms of physical/biological theory (e.g. Churchland)
Our current level of understanding is closest to the dual-aspect theory – we don’t know if we’ll ever know
for sure
SCIENTIFIC APPROACHES TO MIND AND BRAIN
- Early anatomists believed ventricles were the most important part of the brain
- The cortex was often schematically drawn (top) or misrepresented like intestines until the 18 th century
- Gall and Spurzheim (1810) provided the first accurate depiction of the features of the brain
PHRENOLOGY
= scientific approach that looks at the shape of the skull to investigate mental processes
- Different parts of the cortex serve different functions, so differences in personality traits manifest in
differences in cortical size and bumps on the skull, resulting in crude divisions of psychological traits, e.g.
love of animals
- These could sometimes give explanation for very complex concepts, e.g. conscientiousness
- Even though none of these claims were grounded in science, the fact that different parts of the cortex
serve different functions turned out to be correct!
- Modern cognitive neuroscience uses empirical neuroscience methods to ascertain different cognitive
functions and does not assume that each region has one function, or that each function has a discrete
location (unlike phrenology), but empirically shows some degree of functional specialization
FUNCTIONAL SPECIALIZATION
- Penfield found that different parts in our cortex stand for different functions
• He did this by removing the skull in an operation and stimulating the cortex electrically
• E.g. if we are stimulated in the back of the brain, we will see visual sensations, stimulation on the top of
our brain will cause motor movement to happen, while the right side of the brain will make us hear
music
• Nowadays we don’t often use this type of research anymore as it is very invasive, but his findings were
groundbreaking for the cognitive neuroscience
- Broca was a neurologist who came across a patient who couldn’t speak, but could understand it → this
legion (“Tan’s lesion”) is now known as Broca’s area
- Wernicke later observed a patient with poor speech comprehension but good production
There are at least 2 language faculties in the brain (comprehension vs production) that can be
independently affected by brain damage
• This inference can be made even without necessarily knowing where in the brain they are located
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• Cognitive neuropsychology divides the brain into regions
MODELS FOR COGNITION
MINDS WITHOUT BRAINS: THE COMPUTER METAPHOR
- Most of 20th century psychology was concerned with observations of behavior, rather than observations of
the brain during behavior, which led to models of cognition that do not make direct reference to the brain
(e.g. the information-processing models in the ‘50s)
- These models were inspired by thinking of the mind as a series of routines, like those in computers
MINDS WITH VERY ABSTRACT BRAINS: THE CONNECTIONIST MODEL
Connectionist models are mathematical (computational) in nature but don’t involve serial processing and
discrete routines
THE BIRTH OF COGNITIVE NEUROSCIENCE
- ‘70s: structural imaging methods (CT, MRI) enable precise images of the brain (and brain lesions)
- ‘80s: PET adapted to models of cognition developed by psychologists
- ‘85: TMS is first used (a non-invasive, safer equivalent of Penfield’s earlier studies)
- ‘90: level of oxygen in blood used as a measure of cognitive function (the principle behind fMRI), start of
“The decade of the brain”
METHODS OF COGNITIVE NEUROSCIENCE
Method Type Invasiveness Brain property used
EEG/ERP Recording Noninvasive Electrical
Single-cell (and multi-unit) recordings Recording Invasive Electrical
TMS Stimulation Noninvasive Electromagnetic
tES Stimulation Noninvasive Electric
MEG Recording Noninvasive Magnetic
PET Recording Invasive? Hemodynamic
FMRI Recording Noninvasive Hemodynamic
fNIRS Recording Noninvasive Hemodynamic
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- The temporal resolution (X) refers to the accuracy with which one can measure when an event is occurring
- The spatial resolution (Y) refers to the accuracy with which one can measure where an event is occurring, in
this graphic recorded as the level of recording
• High spatial resolution is at the top
• Opening up the skull give a really high spatial resolution, which is why we often use animals in
experiments
COGNITIVE NEUROSCIENCE IS NO PHRENOLOGY
- Modern cognitive neuroscience uses empirical neuroscience methods to ascertain different cognitive
functions and their relationship to neural functioning
- Modern cognitive neuroscience builds upon the information processing diagrams of (cognitive) psychology
- In combination, this provides information not only on what happens where, but also about how it happens
UPDATE OF THE COGNITIVE MODEL: COMPUTATIONAL COGNITIVE NEUROSCIENCE
The past few years, the has been a lot more interest in the computer metaphor, with a new subfield in cognitive
neuroscience called computational cognitive neuroscience, which incorporates new developments in computer
science in the understanding of the brain
- Information goes from layer to layer, like in the computer metaphor, but within those layers, there are
connections like the connectionist model
THE LESIONED AND STIMULATED BRAIN
Studies of humans with brain damage (like Tan, Phineas Gage …) have provided a rich source of information for
cognitive neuroscientists
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- By studying the abnormal, it is possible to gain insights into normal function
- This is a form of reverse engineering: infer the function of a region (or cognitive mechanism) by removing it
and measuring the effect on the rest of the system, e.g. if damage to a region disrupts reading but not
speaking or seeing, then one might conclude that the region is specialized for some aspect of processing
text
- Disruption of brain function comes about through natural damage (e.g. stroke, trauma), elicited damage
(e.g. animal models), or harmless temporary changes induced electro-magnetically (e.g. TMS)
TAXONOMY OF BRAIN MANIPULATION METHODS
WAYS OF ACQUIRING BRAIN DAMAGE
NATURAL DAMAGE
Neurosurgery = operation done in very rare cases of epilepsy where part of the brain is removed,
e.g. case of HM, whose medial temporal lobe was surgically removed, causing him to
have amnesia
Stroke or = disruptions to the blood supply of the brain
cerebrovascular - In Belgium 25.000 new victims every year, of which 15% will not survive and 50%
accident (CVA) will have long-lasting impairments
- 2 types:
• Ischemic infarction (herseninfarct/beroerte) in about 80% of cases, where
buildup of plaque reduces blood flow in the artery
▪ Blood vessels may also become blocked if a fatty clot gets pushed from a
large vessel into a smaller one (an embolism) or a stationary clot
becomes large enough to block the vessel (thrombosis)
▪ On a CT scan, the reduced water content of the affected brain tissue
makes it appear darker
• Hemorrhage or bleeding (hersenbloeding) in about 20% of cases, where a
blood vessel (like an artery) swells into an aneurysm, ruptures and bleeds
into the brain tissue
▪ Depending on how big the rupture is, you will see different symptoms
▪ On a CT scan, accumulated hemoglobin will appear bright
- This can result in global or local death of neurons
• If Broca is affected, we can almost be sure the middle cerebral artery was
affected
• The motor region is bigger, so both the anterior and middle cerebral artery
can affect it, resulting in different kinds of motor problems
• So… the symptoms can help us know where the damage is located
Traumatic brain = caused by a blow to the head
injury (TMI) - Unlike strokes, TMI is more common in younger people, especially males
