Chapter 1: The Development of Neuropsychology
Traumatic Brain Injury (TBI) – a wound to the brain that results from a blow to the head.
LD’s case where his trauma was helped with TBI but there were still residual problems
Neuropsychology – the study of the relation between behavior and brain function.
o The Brain Hypothesis – the idea that the brain is the source of behavior
o The Neuron Hypothesis – the idea that the unit of brain structure and function is the
neuron, or nerve cell.
The Brain Hypothesis
What Is the Brain?
Brain – Old English word for the tissue found within the skull. It has symmetrical halves called
hemispheres, one on the left side of the body and the other on the right.
Cerebrospinal Fluid (CSF) – a tube filled with salty fluid called that cushions the brain and may play a
role in removing metabolic waste.
Parts of the covering of the tube have bulged outward and folded
Cerebral Cortex – the crinkled tissue (of the CSF tube) that has expanded from the front of the tube to
such an extent that it folds over and covers much of the rest of the brain forming an outer layer.
Cortex = “bark” in Latin
Gyri – the folds of the cortex, Gyrus = “circle” in Greek
Sulci – the creases between the Gyri, Sulcus = “trench” in Greek
o Fissures – some large sulci
longitudinal fissure – divides the two hemispheres
lateral fissure – divides each hemisphere into halves.
The cortex of each hemisphere is divided into 4 lobes:
1. The Temporal Lobe – Area of the cortex found laterally on the head, below the lateral sulci
adjacent to the temporal bones.
2. The Frontal Lobe – above the temporal lobe, at the front of the brain.
3. The Parietal Lobe – behind the frontal lobe
4. The Occipital Lobe – area at the back of each hemisphere.
Commissures – the brain’s hemispheres are connected by these pathways, the largest of which is the
The cerebral cortex constitutes most of the Forebrain - it develops from the front part of the tube that
makes up an embryo’s primitive brain. It mediates cognitive functions
Brainstem - the remaining “ tube” underlying the cortex. It is connected to the spinal cord, which
descends down the back in the vertebral column. Brainstem mediates regulatory functions such as eating, drinking, and moving
Spinal cord is responsible for sending commands to the muscles.
To visualize the relations among these parts of the brain, again imagine your upraised fist: the folded
fingers represent the cortex, the heel of the hand represents the brainstem, and the arm rep-resents the
How is the Brain Related to the Rest of the Nervous
Central Nervous System (CNS) – the brain and spinal
cord. It is connected to the rest of the body through nerve
fibres. This DOES NOT regenerate after damage.
Peripheral Nervous System (PNS) - Some nerve fibres
carry information away from the CNS, and others bring
information to it. This DOES regenerate after damage.
Somatic & Autonomic Nervous System
Sensory Pathways – collections of fibres carry messages
for specific sensory systems, such as hearing, vision, and
Somatic Nervous System – subdivision of the PNS that carry information collected on one
side of the body mainly to the cortex in the opposite hemisphere.
o The brain uses this information to construct its current images of the world, its
memories of past events, and its expectations about the future.
Motor Pathways – the groups of nerve fibres that connect the brain and spinal cord to the body’s
muscles through the SNS.
Eg. Eye movements, hand movements and the posture of your body.
Sensory and motor pathways also influence the Autonomic Nervous System – subdivision of PNS; The
part of the nervous system that controls the functions of all the parts of the body, with the exception of
the skeletal muscles, so that the body and its organs are prepared for rest or for vigorous activity.
Specifically: organs muscles of your internal organs, the contractions of your stomach, and the
raising and lowering of your diaphragm.
The Brain Versus the Heart
Alcmaeon of Croton & Empedocles of Acragas: Alcmaeon located mental processes in the brain
brain hypothesis; Empedocles located them in the heart cardiac hypothesis.
Hippocrates & Galen: argues strongly for the brain hypothesis. Galen noted the behavioural
conseuqences of TBI and saw that brain damage caused impairments not the heart.
Cardiac hypothesis left its mark in our language Eg. love is in the heart
Aristotle: The Mind
Aristotle: the first person to develop a formal theory of behaviour. He proposed that a nonmaterial
psyche was responsible for human thoughts, perceptions, and emotions and for such processes as
imagination, opinion, desire, pleasure, pain, memory, and reason. The psyche was independent of the
body but worked through the heart to produce action Christianity’s concept of the soul
Mentalism - the philosophical position that a person’s mind is responsible for behaviour, “ of the mind.”
The brain was thought to work as a whole, but this argues for different parts of the brain
having different functions.
Descartes: The Mind-Body Problem
René Descartes: described a relation between the mind and the brain. Described as nonmaterial and
without spatial extent, the mind, it was different from the body. The body operated on principles similar
to those of a machine, but the mind decided what movements the machine should make. Located the site of action of the mind in the pineal body – a small structure high in the
brainstem – because it’s the only structure in the nervous system not composed of two
bilaterally symmetrical halves and it is located close to the ventricles. The cortex was just a
covering. The mind, working through the pineal body, controlled valves that allowed CSF to
flow from the ventricles through nerves to muscles, filling them and making them move.
Today when the pineal body is damaged, no real changes in behaviour.
Animals do not have minds and are machinelike justified inhumane treatment
Dualism – the position that mind and body are separate but can interact
Mind–Body Problem – for Descartes, a person is capable of being conscious and rational only because of
having a mind, but how can a nonmaterial mind produce movements in a material body?
In order for the mind to affect the body, it would have to expend energy, adding new energy to
the material world. The spontaneous creation of new energy violates a fundamental law of
physics, the law of conservation of matter and energy.
No real support for dualists, so they say the mind and body are parallel not interacting or the
body can affect the mind and the mind cannot affect the body.
Monists – avoid the mind– body problem saying the mind and body are simply a unitary whole.
Darwin and Materialism
Alfred Russell Wallace and Charles Darwin: Materialism – the idea that rational behaviour can be
fully explained by the working of the nervous system without any need to refer to a nonmaterial mind.
Darwin: all living things are said to have Common Descent - as the descendants of that original
organism spread into various habitats through millions of years, they developed structural and
behavioural adaptations that suited them for new ways of life, while retaining many similar
characteristics that reveal their relatedness to one another.
Eg. Nervous system is a common characteristic emerging from one animal evolution
The idea that the brain is responsible for behaviour is rejected by religions but the two can correlate.
Experimental Approached to Brain Function
Localization of Function
Franz Joseph Gall & Johann Casper Spurzheim: The first general theory to present the idea that
different parts of the brain have different functions. They proposed that the cortex and its gyri were
functioning parts of the brain and not just coverings for the pineal body. They showed the brain’s most
distinctive motor pathway, the corticospinal (cortex to spinal cord) tract, leads from the cortex of each
hemisphere to the spinal cord on the opposite side of the body; the cortex sends instructions to the spinal
cord to command movement of the muscles.
Gall: The brain might produce differences in individual abilities into a theory called localization of
function. Eg. a well- developed memory area of the cortex located behind the eyes would cause the eyes
to protrude; the frontal lobes are the seat of intelligence.
They also studied phrenology: bump on the skull indicated a well-developed underlying cortical gyrus
and therefore a greater capacity for a particular behavior; a depression in the same area indicated an
underdeveloped gyrus and a concomitantly reduced faculty.
Spurzheim: Named it Phrenology - the study of the relation between the skull’s surface features and a
person’s faculties. Phrenological Map – the map of the relation between brain functions and the skull
Gall: First complete account of a case in which left-frontal-lobe brain damage was followed by loss of the
ability to speak.
Phrenology was used to make specific personality assessments.
Cranioscopy – a device was placed around the skull to measure the bumps and depressions
o Measures are correlated with the phrenological map to determine behavioural traits. Characteristics are impossible to define and to quantify objectively.
The outer skull does not mirror even the inner skull, much less the surface features of the cortex.
However, Gall’s concept was the foundation for modern views of localization of function.
Localization and Lateralization of Language
Bouillaud: Certain functions are localized in the cortex and,
specifically, that speech is localized in the frontal lobes, specifically
in the left hemisphere, in accordance with Gall’s theory.
Dax: disorders of speech were associated with damage in the left
Auburtin: a patient who lost the ability to speak when pressure
was applied to his ex- posed frontal lobe
Broca: Auburtin was correct: the left frontal lobe was the focus of Tan’s lesion. He located speech in the
third convolution (gyrus) of the frontal lobe on the left side of the brain. He demonstrated that language
was localized; thus different regions of the cortex could have specialized functions. Because speech is
thought to be central to human consciousness, the left hemisphere is the dominant hemisphere.
Lateralization - functions could be localized to a side of the brain.
Broca’s Area – the anterior speech region of the brain
Broca’s Aphasia – syndrome that results from damage in Broca’s Area.
Sequential Programming and Disconnection
Strict Localizationists – people who interpreted Broca’s findings as evidence that language resides
totally in one part of the brain
auditory cortex – part of the cortex that receives
the sensory pathway, or projection, from the ear –
Is located in the temporal lobe, behind Broca’s area
against strict localizationists. A relation between
the functioning of hearing and that of speech, and
he described cases in which aphasic patients had
lesions in this auditory projection area that differed
from those described by Broca in four ways:
i. Damage was evident in the first temporal
ii. No opposite- side paralysis was observed
(Broca’s aphasia is frequently associated with
paralysis of the right arm and leg, as described
iii. Patients could speak fluently, but whatthey
said was confused and made little sense
(Broca’s patients could not articulate, but they
seemed to understand the meaning of words).
iv. Although the patients were able to hear, they
could neither understand nor repeat what
was said to them.
Wernicke’s aphasia is sometimes called temporal-lobe aphasia or fluent aphasia.
Wernicke’s Area – the region of the temporal lobe associated with this form of aphasia.
He proposed that auditory information travels to the temporal lobes from the ears.
o In Wernicke’s area, sounds are processed into auditory images/ideas of objects and
stored. o From Wernicke’s area, auditory ideas can be sent through a pathway called the arcuate
fasciculus leading to Broca’s area, where the representations of speech movements are
o From Broca’s area, neural instructions are sent to muscles that control movements of
the mouth to produce the appropriate sounds.
If the temporal lobe were damaged, speech movements could still be mediated by Broca’s area
but the speech would make no sense, because the person would be unable to monitor words.
Because damage to Broca’s area produces a loss of speech movements without the loss of
sound images, Broca’s aphasia is not accompanied by a loss of understanding.
He predicted Conduction Aphasia – A speech deficit that occurs if the arcuate fibers
connecting the two speech areas were cut, disconnecting the areas but without inflicting
damage on either one.
o Speech sounds and movements and comprehension retains, but speech is still impaired
because the person cannot judge the sense of the words that he or she heard.
Joseph Dejerine: described a case in which th