The input from brain research - summary of chapter 6 of Historical and conceptual issues in psychology, by Brysbaert, M and Rastle, K (second edition)

Foundations of psychology
Chapter 6
The input from brain research

Ideas in Ancient Egypt and Ancient Greece

Beliefs of the ancient Egyptians

The Edwin Smith papyrus

In 1862 an American collector, Edwin Smith, bought a papyrus scroll in the Egyptian city of Luxor.
In the text, written around 1700 BCE, but probably a copy of an older papyrus from 3000 BCE, a series of 48 cases were described dealing with the consequences of head and neck injuries.
Each case included a title, details of the examination, a diagnosis and an indication of the treatment.
The diagnosis consisted of one of three conclusions

• This is an ailment that I will treat
• This is an ailment that I will try to treat
• This is an ailment that I will not treat

The Edwin Smith papyrus: papyrus from Ancient Egypt that contains short descriptions of the symptoms and treatment of different forms of brain injury; named after the person who bought the papyrus in Egypt and had it analysed.
They illustrate how physicians treating wounded soldiers quite early became convinced of the importance of the head (brain) in controlling behaviour.

Beliefs in the wider society

The existence of the Edwin Smith papyrus did not imply that the knowledge contained in it was widespread.
In Ancient Egypt most scholars were convinced that the heart was the seat of the soul.

The roles of the heart and brain in Ancient Greece

The discussion over whether the soul was in the heart or in the brain continued in Ancient Greece.

Plato

Plato and Hippocrates placed the soul in the brain.
Plat also saw a function for the heart.
According to Plato, the soul was divided into three parts

• Highest part
  Responsible for reasoning
  Situated in the brain
  Came directly from the soul of the universe, was immortal, separated from the body and controlled the body
• Dealt with sensation
  Situated in the heart
  Mortal
• Lower part
  Dealt with appetite
  Placed in the liver

Aristotle

Aristotle was convinced that the heart was the seat of the soul.
The function of the brain was to counterbalance the heat of the heart.
The heart and the brain formed a functional unit in which the brain, which was cold, tempered the heat and seething the heart.

Galen

Galen (c. 130-c.200 CE)
Started to experiment on animals.
Demonstrated that the voice came from the brain not from the heart.
He did not think the brain was important for reason or emotion but for the soul residing inside the brain.
The soul lived in the solid parts and produced and stored animal spirits in the apertures in the ventricles.
Animal spirits: spirits that were thought by Galen to travel over the nerves between the ventricles in the brain and body.
Ventricles: apertures in the middle of the brain, which for a long time were thought to contain perceptions, memories and thoughts; seat of the animal spirits.
Galen mostly focused on the ventricles.

Interim summary

• The Edwin Smith papyrus illustrates that practising physicians rapidly made a link between injuries to the brain and mental and behavioural consequences.
• In the Acient Egyptian and Greek societies at large, however, the link between the heart and intelligence was stronger.
• Galen’s experiments clearly established the primacy of the brain and the nerves, rather than the heart and the veins, for the control of movement
• Galen thought that the soul was located in the sold parts of the brain and commanded animal spirits in the ventricles, which travelled through the nerves to the body parts to be influenced.

Further insights into the anatomy and functioning of the nervous system in the Renaissance and the seventeenth and eighteenth centuries

Research about the brain came to a complete standstill in the Middle ages and only really too off again in the nineteenth century.

Developments in the Renaissance

The continuing primacy of the ventricles

Galen’s views remained the norm until well into the eighteenth century.
Andreas Vesalius (1514-1564) resumed dissections and extended them to humans.

Differentiation between the ventricles

Vesalius established for certain that there were three ventricles.
Gradually, the function of the three ventricles became differentiated.

• The front ventricle was assumed to receive information from the senses, and, therefore, was called common sense.
  Also included fantasy and imagination
• The middle of the head
  Comprised thought and judgement
• At the back of the head
  Contained memory

Speech problems can be caused by brain injury

With the rediscovery of Galen’s texts, researchers also regained interest in the relationship between brain injuries and behaviour.
On the basis of his studies, Johann Schenk von Grafenberg concluded, among other things, that after brain damage patients could no longer speak and even though their tongue was not paralysed.
What seemed to happen was that the memory of words had disappeared or at least no longer be accessed.

Developments in the seventeenth and eighteenth centuries

The brain instead of the ventricles

Gradually the investigators turned their focus to the sold parts of the brain rather than the ventricles.
In the seventeenth century they started to pay attention to the difference between the outer layer of the cerebral hemispheres, which looked greyish, and the layer underneath, which had a white appearance.
An increasing number of scholars started to doubt the existence of spirits in the nerves.
Instead, they hypothesised that fluids flowed in them.

Increased interest in reflexes

A topic that started to gain momentum in the seventeenth-eighteenth centuries was the insight that some behaviours were elicited automatically, without voluntary intervention.

A proposed treatment for brain injury

The greater insights into the workings of the nervous system for a long time did not lead to improvements in the treatment of brain injuries.

Interim summary

Advances in the understanding of the brain in the Renaissance and the seventeenth and eighteenth centuries:

• In the Renaissance, Vesaluis and peers followed Galen’s belief that the soul was located in the sold parts of the brain and commanded animal spirits that resided in the ventricles and travelled through the nerves to the other body parts
• There was also a renewed interest in the behavioural consequences of brain injury
• In the seventeenth-eighteenth centuries there was a gradually increasing focus on the brain itself. A distinction was made between the grey and the white matter in the cerebral hemispheres.
• There was also growing interest in the reflex, as a type of response that seemed to escape voluntary control.
• The new insights did not (yet) lead to improved treatment

The breakthroughs of the nineteenth century

A series of five breakthroughs in the nineteenth century irrevocably altered the model of brain functioning and made modern neurophysiology possible

• The discovery of the cerebrospinal axis
• The growing impact of the reflex
• The localisation of brain functions
• The discovery of the nerve cell
• The disentangling of the communication between neurons.

Their timelines largely overlap and the discoveries occurred shortly before psychology was founded as an independent discipline.

The discovery of the cerebrospinal axis

The body remains functioning when the cerebral hemispheres are disconnected

The discovery of the role of the cerebrospinal axis in the regulation of physical functions.

• The received wisdom since Galen was that only the brain was the origin of nerve signals.

This spinal cord was seen as a transmission channel of the spirits or – later – brain fluid.

This view started to be questioned when researchers began to realise that a body remained functioning in a vegetative state when the cerebral hemispheres were taken away or disconnected from the structures at the top end of the spinal cord.
So there were many bodily functions that did not seem to require the cerebral hemispheres.

The new view of the precedence of the spinal cord and the subcortical structures in the control of physical functions agreed with the finding that some animal species had a spinal cord but no brain, whereas the reverse was never observed.

Growing focus on reflexes

The reflex arc

Researchers started to pay more attention to the nature and function of reflexes in brain functioning.
Reflex arc: notion introduced in the nineteenth century to describe the process underlying a reflex; a signal is picked up by sensory receptors, transmitted to the spinal cord through an afferent nerve, transferred to interneurons, which activate motor neurons that send a motor command over an efferent nerve to initiate the withdrawal movement.

The reflex arc as the basis of mental functioning

Some time later, researchers extended Hall’s reflex arc from the spinal cord to the complete brain.
For them, the reflex was no longer mode of action in the nervous system among others, but the basal unit from which the remaining nervous functions evolved.

Localisation of brain functions

The brain equipotentiality theory

A major discussion taking place in the nineteenth century was whether different psychological functions were localised in different parts of the brain or whether the whole brain was involved in all of them.

• Before, it had been widely assumed that the brain was a single organ, without further subdivisions.
  Brain equipotentiality theory: theory saying that all parts of the brain have equal significance and are involved in each task; first thought to apply to the complete brain; since the nineteenth century limited to the cerebral hemispheres.
• A series of findings in the nineteenth century convinced an increasing number of investigators that this theory was wrong and had to be replaced by the localisation theory
  Localisation theory: theory saying that brain processes are localised, meaning only part of the brain underlies a particular mental function.

Language production is controlled by the front parts of the brain

In 1825 Jean-Baptiste Bouillaud presented evidence which according to him proved that speech was controlled by the front parts of the brain, the parts of the left and right half touching the forehead.

Language production is controlled by the left frontal lobe

In 1861 Paul Broca repeated and extend Bouillaud’s work and presented evidence that speech production was controlled by the frontal lobes.
He claimed that only a region of the frontal lobe of the left hemisphere was involved.
This region has since been called Broca’s area.

Language understanding and the posterior part of the brain

Karl Wernicke in 1874 presented evidence that language problems could also occur after damage to the rear part of the left hemisphere.
These problems had to do with the understanding of language.

The discovery of the nerve cell

The finding that the grey matter of the cerebral hemispheres consisted of billions of cells and the white matter and the nerves were the ‘tails’ (axons) of these cells.

The availability of better microscopes

First, microscopes of sufficient quality had to be built and used correctly.
These only become available in the nineteenth century.
Before, magnification was not strong enough and there were major distortions in the images obtained.

New techniques to stain the brain tissue

A way to colour the brain cells with their fine details.
There was little to be noticed about the organisation of brain tissue as long as the researchers had to look at the raw material.

Disentangling communication in the nervous system

Individual neurons instead of a continuous network

The big question among brain physiologists was whether the network was a continuous structure or whether it consisted of individual cells.
It would take nearly half a century before it became generally accepted that the network was composed of individual cells.
Neuron: brain cell; basic unit of the nervous system; contains a cell body, dendrites and an axon.

Once it was accepted that the nervous system consisted of billions of independent neurons, the next challenge was to explain how they stored and exchanged information.

Electricity within neurons

A new idea emerging at the end of the eighteenth century was that communication in the nervous system might resemble the transmission of electric signals.
Physiologists were struck by the similarities between electrical signals and what happened in the nerves.

The first to find clear evidence for the involvement of electricity in the nervous system was Luigi Galvani.
Although in hindsight he misinterpreted quite a lot of findings, it was undeniable that body movement could be generated by an electric current applied to a nerve.

Communication between neurons: the synapse

In the twentieth century the communication between neurons also became understood.
Although a small part of this communication is electrical, the bulk is achieved chemically, by means of neurotransmitters.
Neurotransmitters: chemical substance used to communicate between neurons; is released from the synapse when a signal arrives through the axon; can be affected by drugs.

Interim summary

Five big breakthroughs in the nineteenth century

• Understanding that the spinal cord was an integral part of the central nervous system and was involved in the control of many bodily functions
• Discovery that many processes in the central nervous system were reflexes that did not need voluntary initiation; question to what extent higher cognitive functions could be considered as reflexes as well
• Intense discussions between proponents of brain equiptotentiality and adherents of brain localisation; initially the former were dominant; increasingly, however, evidence for the latter position was found
• Discovery that the brain consisted of a network of individual neurons that communicated with each other; required good microscopes and techniques to stain neurons
• Discovery that the neuron store and transfer information by means of electro-chemical signals; electrical information mainly involved in intra-cell communication, chemical information transfer important for communication between neurons

The emergence of neuropsychology in the twentieth century

Localisation studies in the World Wars

The World Wars resulted in new insights.

Vision problems after gun-shot wounds at the back of the head

Gordon Holmes (1876-1965) examined the consequences of small-scale wounds at the back of the head in World War I.

World War II and prosopagnosia

Joachim Bodamer described soldiers who lost their ability to recognise faces as a consequence of an injury to the rear of the brain. This is prosopagnosia.

The start of neuropsychology

The mission of neuropsychology

Increasingly, in the second half of the twentieth century psychologists rather than physicians became involved in studying the behavioural consequences of brain injury.
Neuropsychologists: branch of psychological research and practice that looks at the relationship between brain and behaviour; research traditionally focused on understanding the consequences of brain damage and localising the affected tissue; practice aimed at assessing the behavioural and mental consequences of the injury and administering the rehabilitation programme.
Neuropsychology was presented as a new link between psychologists and the medical world.

A change of focus: cognitive neuropsychology

Dissent among neuropsychologists

In the 1970 and 1980s, a number of neuropsychologist became dissatisfied with the way in which the subject matter was investigated.
They had two grievances

• The localisation issue turned out toe be difficult to address on the basis of human brain injuries
  All that could be done was to establish a correlation between symptoms measured while the patient was alive and brain damage observed after the patient had died
  Damage caused by brain injuries and strokes is usually widespread and not limited to one specific brain structure
• The results of the examinations rarely went beyond a list of symptoms displayed by various patients
  There was little theory behind the enterprise

What neuropsychology had to do, the dissenters argued, was to use observations from patients with brain damage to test and amend the information-processing models proposed by the cognitive psychologists.

A new name

To emphasise the difference between the new type of research and the traditional neuropsychological approach, a new name was coined. Cognitive neuropsychology.
Cognitive neuropsychology: part of neuropsychology aimed at understanding and treating the behavioural consequences of brain damage within the information processing models proposed by cognitive psychologists.
By relating the consequences of brain damage to the theories of normal functioning, the cognitive neuropsychologists explicitly aimed to increase the impact of their research within the departments of psychology.

Deep dyslexia

A landmark publication in the history of cognitive neuropsychology was a book on deep dyslexia.
Deep dyslexia: a condition of strongly impaired reading after brain injury with a very particular symptom; sometimes, when patients try to identify a word, they do not read the word itself but a semantically related word.

By integrating neuropsychological research in the mainstream of cognitive research, the cognitive neuropsychologists not only advanced the cognitive information processing models, but also ensured that the findings from the clinic became central to psychological thinking and teaching.

Interim summary

Neuropsychology

• Examination of bullet wounds in the World Wars provided physicians with more detailed knowledge about the behavioural consequences of brain injuries. Two famous examples were the partial loss of vision after gun-shot wounds above the neck, and the inability to recognise faces
• Research and treatment of the consequences of brain damage were increasingly taken over by psychologists, who called themselves neuropsychologists
• In the 1970 and 1980s a number of neuropsychologists started to study the implications of brain damage fro the information-processing models proposed by cognitive psychologists; this was the start of cognitive neuropsychology
• One of the first topics addressed by the new approach was deep dyslexia

Brain imaging and the turn to neuroscience

For a long time the evidence about the neurophysiology of the brain and the localisation of functions was based on post-mortem analysis.
In the twentieth century, scientists increasingly managed to extract information from a working brain.

• One of the first techniques was single-cell recording.

Non-invasive techniques: methods in neuroscience that allow the study of the workings of the brain without surgery or the use of irreversible interventions.

Measuring electrical signals from groups of cells

EEG recording

Hans Berger
Reasoned that if brain activity was electrical activity, he might be able to pick up some signals if he puts electrodes on the human scalp.
EEG: electroencephalogram; outcome of measurement of electrical brain activity by means of sensors placed on the scalp; routinely used in hospitals for the detection of epilepsy.

Event related potentials and magnetoencephalography

As the accuracy of the EEG recordings grew, two further applications became available.

• The measurement of changes in the electrical signal as a function of specific stimuli
  Event Related Potential (ERP): signal obtained by averaging EEG signals that are repeated a number of times; allows researchers to look for differences in the signal as a function of characteristics of the stimulus.
• One could try to localise the source of the electrical signal

Magnetoencephalography (MEG): measurement of the electrical brain activity by means of measurement of the magnetic field around the head; is one of the most promising brain imaging techniques, because it has the potential of both a high temporal and spatial resolution.

Measuring blood flow in the brain

By looking at the blood flow it is possible to know which brain regions are particularly active during a task

PET and fMRI

There are several ways to determine the blood flow, depending on precise the measurement has to be.

• Position emission tomography (PET): brain imaging technique based on measurement of a radioactive tracer injected into the bloodstream
• fMRI: brain imaging technique based on the measurement of blood with oxygen vs blood without oxygen; currently the most popular imaging technique because of its high spatial resolution; has rather low temporal resolution

Measuring effects of ‘virtual lesions’

TMS

Because brain activity is electrical electricity, it is possible to interfere with it by introducing a weak electric current in the neurons.
Transcranial magnetic stimulation (TMS): stimulation of a brain region by means of a coil placed on the head; allows temporary interference with the processing of a small part of the brain.

The birth of cognitive neuroscience

Cognitive neuroscience: testing the cognitive information-processing models with brain imaging techniques

The availability of techniques to measure human brain activity while participants are performing mental operations opened a completely new field of research for psychologists.
Psychologists increasingly relied on brain imaging data to test their theories.
Cognitive neuroscience: the scientific study of the biological mechanisms underlying cognition; largely based on brain imaging techniques, TMS and the measurement of electrical activity.

Is cognitive neuroscience more than high-tech localisation?

According to some authors, the findings of fMRI are more comparable to the localisation efforts of traditional neuropsychology than to the testing of cognitive models done in cognitive neuropsychology.

In defence of cognitive neuroscience

Arguments against the claim that cognitive neuroscientific studies are unable to provide anything more than information about the localisation of brain activity

• There is a difference between empirically showing the brain regions involved in a particular task and speculating about them.
• Localisation of the brain activity while a person is performing a task does provide information about the processes involved
• On the basis of brain imaging data it is now recognised that, although the brain is compartmentalised into regions with specialised functions, all tasks require the interaction of several areas distributed over distant parts of the brain.

Interim summary

• Single-cell recording allows researchers to find out to which type of information individual neurons respond; it is an invasive technique
• EEG recordings allow researchers to pick up the summed electrical activity of groups of cells non-invasively. They allow researchers to detect cases of epilepsy and to discover different stages of sleep
• ERP studies are based on EEG recordings and allow researchers to find out how the brain response changes as a function of different types of stimuli
• MEG scanning also measures the electrical activity of groups of neurons and allows researchers to add localisation to the ERP studies
• PET scanning allows researchers to see which brain areas require extra blood during the performance of tasks by tracing a radioactive substance injected into the blood
• fMRI scanning allows researchers to localise brain activity on the basis of oxygen use. Produces more detailed images than PET and does not require an injection of substance into participants.
• TMS allows researchers to interfere briefly with the activity of a small region of the grey matter and to examine the effects of this inference on the time needed to complete a particular task. Makes it possible to ascertain that the brain region is crucial for performance
• The above techniques have allowed researchers to measure brain activity while participants are performing mental tasks. This created a new research field, cognitive neuroscience
• Not everyone is convinced that brain imaging techniques allow researchers to examine the detailed cognitive processes involved in correct task performance

Focus on: can delusions be investigated with the cognitive neurospsychological approach?

Cognitive neuropsychiatry as a new research area

Cognitive neuropsychiatry: subfield that tries to understand consequences of mental disorders in terms of breakdowns in the cognitive models of normal psychological functioning.

Interim summary

• Cognitive neuropsychiatry states that symptoms of mental disorders can be understood as the result of errors in the cognitive information-processing model that accounts for normal psychological functioning
• The Capgras delusion refers to a situation in which a person still recognises close relatives, but is convinced that they have been replaced by look-alikes
• The Freudian interpretation of the delusion refers to conflicting feelings towards the relatives, which result in a dissociation between the absent loved persons and the present hated look-alikes
• Cognitive neuropsychiatry argues that the condition results from blocked information transfer in an unconscious, emotion-related processing route that under normal circumstances elicits and emotional response each time we encounter a familiar person. As a result, the relatives feel strange, even though we recognise them.