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Lecture 1
History of Neuropsychology and
Neuroanatomy
Vedran Lovic
Lecture 1 Outline:
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History of neuropsychology
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Neuroanatomy
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Ancient history
Phrenology
Localization vs. antilocalization
Hindbrain
Midbrain
Forebrain**
Cortical organization
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Luria’’s model vs. newer hierarchical models
Luria
What is Neuropsychology and
Cognitive Neuroscience?
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Neuropsychology is a study of relation between
(human) brain function and behavior
? Cognitive Neuroscience comprises
investigations of all mental functions that are
linked to neural processes – ranging from
investigations in animals to humans and from
experiments performed in the laboratory to
computer simulations
? Neurology is a branch of medical science that
deals with the nervous system, both normal and
diseased
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Two Approaches to Studying the
Brain--Behaviour Relationship
Brain
Neurological – “what do different parts of the
brain do?”
do?” Useful in brain surgery.
2. Psychological – “what are the brain
mechanisms of specific functions (e.g.,
memory or language etc.)?”
etc.)?”
? In this course we will primarily adopt the
psychological approach to examining the
brain-- behaviour relationship
brain
? However, we will also have other approaches
1.
The Brain Hypotheses
? The
brain hypothesis: the idea that brain
is the source of behavior
Prehistoric
? Early
history –soul
or spirit controls
behavior
? Cranial trephinations
– used to relive
seizures and injuries
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Early History
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Egyptians – packed
mummies with organs
thought to be important in the
afterlife (as they were
important in life)
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Heart, liver, lungs etc.
But - NO BRAIN
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Ancient Greece &
Rome
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Alcmeon of Croton (500 B.C.) - brain
hypothesis
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Empedocles (490(490-430 B.C.) –
cardiac hypothesis
Aristotle (384(384-322 B.C.) –
heart/cardiac hypothesis
Hippocrates (460(460-377 B.C.) and
Galen (129(129- 210 A.D.) – clinicians –
behavioral deficits associated with
brain damage; senses lead to the
brain
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Descartes - Dualism
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How does the brain control
behavior?
Rene Descartes (1569(1569-1650) –
mind and body separate – dualism
Monism – mind and brain are the
same thing
Is mind separate from the brain
and its activity?
Does the brain work as a unit with
each part contributing to the
whole?
Is the brain composed of individual
processing parts, each carrying out
specific function?
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Darwin and Materialism
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Russell Wallace and Charles Darwin
Materialism – the idea that rational behavior can be fully
explained by the working of the nervous system without any
need to refer to a nonmaterial mind
Common decent
Through the evolution, different species developed unique
characteristics, yet they retained many common traits (e.g.,
the brain)
Since the brain controls the behavior of nonnon-human
animals, the brain also controls human behavior
How does the brain control the behavior?
Phrenology
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Franz Joseph Gall (1758(1758- 1828) and
Johann Casper Spurzheim – anatomists
Pyramidal tract – connections from
cortex to the spinal cord – suggesting that
cortex sends instructions to the spinal
cord to command the movement of
muscles (also known as the corticospinal
pathway)
Corpus callosum – large pathway
connecting two hemispheres
phrenology – relationship between the
skull’’s surface and underlying cortex and
skull
individual’’s faculties
individual
LOCALIZATION OF FUNCTION –
hypothetically, the control of each kind of
behavior by a different specific brain area
Phrenology
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Evidence: anecdotes, paintings etc.
Cases of patricide
25 murderers
No interest in brain injury cases
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Problems with Phrenology
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Incorrect assumption that the size of the skull accurately
reflects the size of the underlying brain. Skull thickness
is variable.
No scientific analysis of the psychological ‘factors
factors’’. No
reason to think that there is a faculty of secretiveness,
amativeness, etc.
Today we still don’
don’t know what the basic personality
traits are
Methods were not scientific - anecdotal, personal, no
independent analysis of faculties and skull
protuberances, etc. Techniques were entirely
correlational.
Anti--Localization
Anti
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Pierre Flourens
Lesioning different parts of the cortex and
observing the changes in behavior
Most animals eventually recovered – no
localization – cortex works as a whole
He did find that brain stem had
specialized functions – e.g., breathing –
and that the cerebellum is important for
coordination
Problems – choice of animals and
behaviors selected for observations
Broca – Localization of Language
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Paul Broca (1824(1824- 1880)
1861, NonNon-fluent patient
Laborgne, a.k.a. “Tan
Tan””
Did he have goodgoodcomprehension?
Did he have any other deficits?
Right hemiplegia – paralysis of
the right side of the body
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Broca – Localization of
Language
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Autopsy: Tan had damage in third
convolution in the left frontal cortex
Broca found additional 8 cases
exemplifying similar effects
Lateralization of function:
functions can be localized to one
side of the brain
Broca’’s aphasia – expressive, or
Broca
non-- fluent, aphasia that is chiefly
non
defect of speech
Presenting argument: behavior,
such as language, is controlled by
a specific brain area and (2)
destroying the area selectively
destroys he behavior – strict
localizationist
Wernicke – Multiple
Language Areas
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Carl Wernicke (1833(1833-1892)
Aphasic patients - Fluent
with poor comprehension
Poor repetition
Did they have any other
deficits?
No contralateral hemiplegia
brain damage in posterior
temporal lobes
Wernicke’’ s aphasia/fluent
Wernicke
aphasia/fluent
aphasia/sensory aphasia
Electrophysiological Confirmation
of Localization
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Gustav Theodor Fritsch (1838(1838-1929)
and Eduard Hitzig (1838(1838-1907)
Mechanical irritation of the soldiers’
soldiers’
brains caused twitching in
contralateral limbs
Electrical stimulation of cortex of dogs
Localization of motor control –
topographical representation of body
parts.
Conclusion: these parts of the brain
control the movement of particular
parts of the body – function is
localized here
Necessary? Sufficient?
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Antilocalizationists
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Friedrich L. Goltz (1834(1834-1902) –
dog lesions – same same areas
the Fritsch and Hitzig stimulated
– dogs could move!!!!
Problems with Fritsch & Hitzig
claims???
cortex NECESSARY and
SUFFICIENT for movement – not
true
Hughlings-Jackson
HughlingsHierarchical Organization
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Hierarchical organization – principle of cerebral
organization in which information is processed
serially, with each level of processing assumed to
represent the elaboration of some hypothetical
process
Nervous system is arranged in functional hierarchy
(the spinal cord, the brain stem and the forebrain)
Herbert Spencer’
Spencer ’s ideas of evolution ? injury leads
to dissolution
Higher level controls more complex behavior
through lower levels
Distributed systems – mediation of behavior by
neurons and connections between neurons that are
located in different areas of the brain
How does this model fit with Fritsch & Hitzig and
Goltz findings?
Neuroanatomy
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Purpose of this lecture:
? Structure
and function are two sides of the
same coin
? Object
Object’’s structure imposes physical
constraints on its function
? What are the major structural components
of the nervous system and how are these
components interconnected?
Why Brains?
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Brains are organs that help organisms
propagate their genes
? Hence, nervous systems are design to sense
what is going on around them (sensory organs
and processing of sensory information) and act
on the world around us (motor functions);
However, in between sensing and acting on
the world we process a lot of information
? We will see that in general, these divisions
between sensory, motor and association
areas are present throughout the nervous
system
Neuroanatomy
? Study
of the nervous system’
system’s structure
levels of description
? Gross neuroanatomy - general
structures and connections visible to the
naked eye
? Fine neuroanatomy – (microscopic)
organization of neurons and their
connections
? Many
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Neurons and Glial Cells
? ~180 billion cells
? Stem cells –
undifferentiated cells
? Ventricular zone – brain
areas around the ventricles
where stem cell can be
found in adulthood
? Neurogenesis – the
mitotic division of nonnonneuronal cells to produce
neurons
Neurons and Glial Cells
Grey, White and Reticular Matter
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Nucleus – a large wellwell-defined group of cell bodies
Tract or path – a large collection of axons projecting to
or away from a nucleus or layer
Nerves – tracts that enter or leave the central nervous
system
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Staining
Orientation
Orientation
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Superior – top - dorsal
Inferior – bottom - ventral
Anterior – rostral - front
Posterior-- caudal – back
Posterior
Ipsilateral – same side
Contralateral – opposite side
Proximal – close
Distal – far
Medial – towards midline
Lateral – away from midline
Afferent – approaching
Efferent - leaving
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Major Divisions of the
Nervous System
1.
The Central Nervous
System (CNS)
a)
The Brain
b)
2.
a)
b)
The Spinal Cord
The Peripheral Nervous
System (PNS)
The Somatic Nervous
system (from sense organs
to the CNS and from the
CNS to the muscles and
glands)
The Autonomic Nervous
system (involuntary
muscles)
i) sympathetic and
ii) parasympathetic
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Major Divisions of the Nervous System
Cortex
Limbic
Basal Ganglia Diencephalon
The Spinal Cord
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The spinal column is made
up of a series of small bones
called vertebrae
Segments of our bodies
correspond to segments of
the spinal cord
Each body segment is called
dermatome
5 groups (30 in total)
Peripheral nerves
The Spinal Cord
Dorsal
Sensory
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Francois Magendie –
1822
Charles Bell – 1811
Bell-Megendie Law –
Bellthe dorsal roots of the
spinal cord are sensory
and the ventral roots of
the spinal cord are
motor
Ventral
Motor
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The Brain - Meninges
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Meninges – protective
sheath around the
brain and the spinal
cord: dura matter,
arachnoid layer and pia
matter
? Meningitis –
inflammation of the
meninges due to viral
or bacterial infection
Major Brain Divisions
Major Brain Divisions
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The Hind Brain
(Rhombencephalon)
1.
Myelencephalon (spinal brain)
2.
-medulla oblongata (cranial
nerves nuclei), reticular
formation
Metencephalon (across(across-brain)
-cerebellum, pons, reticular
formation
The Hind Brain
Myelencephalon - Medulla
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Many cell bodies of the
12 cranial nerves
Motor fibers crossover
Vital functions
(breathing, heart rate)
The Hindbrain
Myelencephalon – Reticular formation
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The Hind Brain
Metencephalon – Cerebellum
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Balance and fine motor movement
Learning and cognition
The Hind Brain
Metencephalon – Pons
? Pons
is a “bridge
bridge””
between the brain
and the cerebellum
as well as sensory
inputs (vestibular
functions, eye
movements,
auditory info etc).
The Midbrain (Mesencephalon)
1. Tegmentum (floor)
- Reticular system (arousal, attention)
- Locus of different nuclear groups
that synthesizes neurotransmitters
2. Tectum (roof)
- superior colliculuscolliculus- visual
- inferior colliculuscolliculus- auditory
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The Forebrain
(Prosencephalon)
1.
2.
Diencephalon
(“between brain”
brain”)
Telencephalon
(“end brain)
The Forebrain
The Diencephalon
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Thalamus
( “ inner chamber”
chamber” )
? Epithalamus
( “ upper chamber”
chamber” )
? Hypothalamus
( “ lower chamber”
chamber” )
The Thalamus
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Sensory relay nuclei (auditory, somatosensory, visual)
Motor relay nuclei (from cerebellum and globus pallidus to motor
cortex)
Association nuclei ( between association areas of cortex, limbic relay
nuclei-- from hypothalamus to cingulate)
nuclei
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The Hypothalamus
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Approximately 22 nuclei
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0.3% of brain weight yet it is
involved in nearly all aspects
of motivated behavior
feeding, sleeping, sexual
behavior, temperature
regulation, emotional
behavior, maternal behavior,
endocrine function
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pituitary gland
The Telencephalon
1.
2.
3.
Neocortex
Basal Ganglia
Limbic system
The Basal Ganglia
1.
2.
3.
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globus pallidus
putamen
caudate nucleus
supports muscular activity,
posture, balance, locomotion,
starting and stopping movement
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The Limbic
System
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Hippocampus
Amygdala
Cingulate
Mammillary bodies
Olfactory Bulb
Hypothalamus
Regulation of emotion and
memory
The Neocortex or Cortex
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Higher cognition functions,
planning of behavior, attention,
memories, language etc.
Gyrus – the protruding rounded
surface
Sulcus – the enfolded regions
that appear as lines and creases
(fissure)
80% of brain volume
2500 cm2
Thickness 1.51.5-3.0 mm
The Cortex – Hemispheres and
Lobes
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Cytoarchitectonic Maps of The Cortex
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Maps based on cell
structure
6 layers
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Output layers: V and
VI
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Input layer: IV
Association layers: I, II
and III
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Cytoarchitectonic Maps of The Cortex
? Motor areas of the
brain have larger V
and VI layers
? Sensory areas of
the brain have
larger layer IV
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Cytoarchitectonic Maps of The Cortex
? Brodmann
Brodmann’’s
Map
W. W. Norton
W. W. Norton
Projection Map
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Projection map – made by tracing axons
from the sensory systems into the brain and
from the neocortex to the motor systems in
the brain stem and spinal cord
Primary projection areas – areas that first
receive a connection from another system
Secondary projection areas – areas that
receive inputs from primary areas (thought to
be involved in more complex sensory or
perceptual or motor functions)
Tertiary areas – areas that lie between the
various secondary areas (sometimes referred
to as association areas – complex functions
such as language, planning, attention and
memory)
Cortical
Connections
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Functional Maps
– Wilder Penfield
Maps of functions mapped
out on the cortex
Best know is Penfield’
Penfield’s map
of motor and sensory cortex
These maps are plastic –
they can change in response
to experience – decreased or
increased use
Monkeys with two fingers
connected
Severed fingers
Training that requires
increased use of particular
fingers
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Cortical Columns, Spots and
Stripes
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Module - hypothetical
unit of cortical
organization believed
to represent a
vertically organized
intracortical
connectivity that is
assumed to
correspond to a single
functional unit.
Sometimes used as a
synonym for column.
The Binding Problem
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theoretical problem with integration of
sensory information. Because a single
sensory event is analyzed by multiple
parallel channels that do not converge on
a single region, there is said to be a
problem in binding together the
segregated analyses into a single sensory
experience.
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Functional Organization of the
Cortex
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Alexander Luria – divided cortex into
two functional units:
posterior cortex is the sensory unit
(receives sensations, processes them
and stores them as information)
anterior cortex is the motor unit (it
formulates intentions, organizes them
into programs of action, and executes
the programs)
Within each there is a 3 layer
hierarchy: primary, secondary and
tertiary cortex
Tertiary areas – formulation
Secondary areas – elaboration
Primary areas - execution
Evaluating the Hierarchical
Model
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Assumptions:
Brain processes information serially – one step at the time
Serial processing is hierarchical – each level of processing adds
complexity
Our perceptions of the world are unified and coherent entities
Problems:
Cortical areas are not connected serially
Each area of the cortex has multiple connections, probably under taking
many functions
Finally, we experience a single percept despite the fact that th ere is no
single terminal area producing it (binding problem)
Does this mean that there is no hierarchy or order in cortical
organization?
Luria vs. Newer Models of
Cortical Functioning
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