Samenvatting boek Neuropsychologie | Anouk Wiersma
Neuropsychologie
Samenvatti ng – Fundamentals of Human Neuropsychology
Lecture 1
Chapter 1: The development of neuropsychology
1.2: Perspectives on the brain and behavior
Evolution by natural selection
- Darwin: all organisms, both living and extinct, are descended from an ancestor that lived in
the remote past.
o Animals have similar traits because those traits are passed from parents to their
offspring.
o Natural selection: Darwin’s theory for explaining how new species evolve and how
the change over time.
Species: group of organisms that can breed among themselves but usually
not with members of other species.
Individual organisms within a species vary in their phenotype, the traits that
we can see or measure.
Natural selection and heritable factors
- Traits, like color an height, are heritable factors we call genes.
o The unequal ability of individual organisms to survive and reproduce is related to the
different genes they inherit from their parents and pass on to their offspring.
- The environment plays a role in how genes express traits explained by epigenetics.
- Environment and experience play an role in how animals adapt and learn. Adaption and
learning are in turn enabled by the brain’s ability to form new connections and pathways.
- Neuroplasticity: the brain can physically and chemically change.
1.3: Brain functions: insights from brain injury
- Understanding of brain functions has its origins in individuals with brain damage.
Localization of function
- First general theory to propose that different parts of the brain have different functions was
developed in the early 1800s by Gall and Spurzheim.
o They proposed that the cortex and its gyri were functioning parts of the brain and not
just coverings for the pineal body.
Supported by showing that the brain’s most distinctive motor pathway, the
corticospinal tract, leads from the cortex of each hemisphere to the spinal
cord on the opposite of the body cortex sends instructions to the spinal
cord to command muscles to move.
Also: recognized that the two symmetrical hemispheres of the brain are
connect and can thus interact.
o Observed that students with good memories had large, protruding eyes and surmised
that a well-develop memory area of the cortex located behind the eyes would cause
them to protrude developed the hypothesis of localization of function.
o Observed other people with other bumps on the skull that indicate a well-developed
underlying cortical gyrus, related to a greater capacity for a particular behavior, or a
depression in the same area indicated an underdeveloped gyrus and a concomitantly
reduced faculty.
, Samenvatting boek Neuropsychologie | Anouk Wiersma
o Phrenology: study of the relation between the skull’s
surface features and a person’s mental faculties.
As a science, phrenology was a flob;
characteristics such as faith, self-love, and
veneration are impossible to define and to
quantify objectively.
o Gall gave the first account of a case in which frontal-lobe
brain damage was followed by loss of the ability to speak.
Lateralization of function
- Language is both localized in the brain and lateralized – located
on one side of the brain.
o Lateralization of function: one cerebral hemisphere can
perform a function not shared by the other.
- Physicians had long recognized that damage to a hemisphere of the brain impairs movement
of the opposite side of the body.
- Paul Broca located speech in the third convolution (gyrus) of the frontal lobe on the left side
of the brain.
o The left hemisphere is referred to as the dominant hemisphere to recognize its
special role in language.
o Anterior speech region is called Broca’s area, and the syndrome that results from its
damage is called Broca aphasia.
Patient could not articulate, but they could understand the meaning of words
movement problem.
- Carl Wernicke created the first model of how the brain produces language.
o Examined patients that had lesions in the auditory area of the temporal lobe. These
patients displayed no opposite-side paralysis and they could speak fluently, but what
they said was confused and made little sense. And although they could hear, they
could neither understand nor repeat what was said to them. Wernicke syndrome,
also called temperal-lobe aphasia or fluent aphasia; problem of understanding.
Associated region in the temporal lobe is called Wernicke’s area.
o Wernicke’s model: sound sensation enter the brain through the auditory pathway
sound images are stored in Wernicke’s area and are sent to Broca’s area for
articulation over the motor pathway.
Predicted a new language disorder based on this model; he suggested that, if
the arcuate fibers connecting the two speech areas were cut, disconnecting
the areas but without inflicting damage on either one, a speech deficit that
Wernicke described as conduction aphasia would result.
In this condition, speech sounds and movements are retained, but
speech is impaired because it cannot be conducted from one region
to the other.
Different brain regions have different functions, but the must interact to work
properly.
- Distributed function
o Many functions are distributed; that is, they depend on many brain regions.
This feature of brain organization allows recovery of function and is central to
rehabilitation after brain damage.
- Hierarchical organization
o Neurologist John Hughlings-Jackson proposed the principal of cerebral organization in
which information is processed serially and organized as a functional hierarchy.
, Samenvatting boek Neuropsychologie | Anouk Wiersma
Each successively higher level controls more complex aspects of behavior and
does so via the lower levels.
Three levels: the spinal cord, the brain stem, and the forebrain.
o We have multiple memory systems.
Patient H.M.; got surgery to treat his epilepsy, in which parts of the temporal
lobe from the left and right hemisphere were removed.
The surgery stopped the epilepsy but left him with a severe memory
problem: amnesia, partial or total memory loss.
His case reveals that rather than a single memory structure in the
brain, a number of neural structures encode memories separately
and in parallel.
H.M. appeared to have retained memories from before surgery but
was unable to form new memories.
o Another surgery for people with epileptic seizures involved cutting the corpus
collosum, resulting in two ‘separate’ brain split-brain patients.
This surgery was effective in reducing the seizures and in improving the lives
of the patients.
o Although we may think that our behavior derives from our conscious direction, much
of it is unconscious.
Dorsal and ventral stream of vision.
Ventral stream: from the visual cortex to the temporal lobe for object
identification.
o Mediates actions controlled by conscious visual perception.
o Lesions in this region result in agnosia; unable to identify
objects.
Dorsal stream: from the visual cortex to the parietal cortex to guide
action relative to objects.
o Mediates actions controlled by unconscious visual processes.
o Lesions in this region result in optic ataxia; making errors in
reaching for objects while still being able to describe the
objects accurately.
, Samenvatting boek Neuropsychologie | Anouk Wiersma
Chapter 2: Research on the origins of the human brain and behavior
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- Hominins: last family in the cladogram, the human family.
o Includes modern humans, as well as extinct human species and immediate ancestors.
o Characterized by being taller than predecessor apes; they are also bipedal, have long
legs, and are such great travelers that some species have populated every continent.
2.1: Human origins and the origins of larger brains
- The evolution of humans is not linear.
- Archeological research:
o Use skeletal remains to reveal similarities and differences between other hominins
and us.
Fossils of Neanderthals were the first ancestral humans to be discovered.
- Biochemical and genetic research:
o Genes direct the body’s cells to produce protein molecules composed of long chains
of amino acids. The amino acid sequence of a cellular protein in one species can be
compared to that in another species.
o Species relatedness is also determined by comparing deoxyribonucleic acid (DNA).
A comparison of the gene sequences of modern humans and chimpanzees
suggests that they share 99% of their genes and are each other’s closest
living relatives.
- Evolution of the human brain and behavior
o Australopithecus: our distant ancestor
Walked upright and had hand use abilities similar to ours, and some used
tools.
Scientist have deduced their upright posture from the shape of their back,
pelvic, knee, and foot bones.
Brain size was not much different from that of chimpanzee.
o The first humans
Oldest fossils designated as genus Homo are those found by Mary and Louis
Leakly in 1964, dated to about 2 million years old.
Strongly resembled Australopithecus, but more closely resembled
modern humans in having larger brains.
- Relating brain size and behavior
o Scientists who study brain evolution propose that changes in brain size and
complexity in different species enable more complex behavior to evolve.
