Week 1
Chapter 1
A Definition of Clinical Neuropsychology and Its Aims
Clinical neuropsychology studies the relationship between human
behavior, emotions, and cognitive functions in relation to brain damage or
disorders. It serves both applied and academic purposes.
- The applied aspect focuses on diagnosing, treating, rehabilitating, and
preventing neurological disorders.
- Academically, it seeks to understand normal brain function by studying
cognitive impairments in brain-damaged individuals through controlled
experiments.
Relationship of Clinical Neuropsychology to Other Disciplines
Clinical neuropsychology overlaps with multiple disciplines:
- Neurology: Focuses on the medical aspects of central nervous system
disorders, including pathology and treatment.
- Cognitive Psychology: Aims to understand workings of human brain
by analyzing higher cognitive functions. Studies the functioning of the
mind through controlled cognitive experiments using unimpaired
participants.
- Cognitive Neuropsychology: A hybrid field that applies cognitive
psychology techniques to brain-damaged patients, primarily to
understand normal cognitive processes.
Clinical neuropsychology is positioned between neurology and cognitive
neuropsychology, integrating medical aspects of brain disorders with
higher cognitive function analysis.
- Some practitioners combine roles, such as behavioral neurologists or
neuropsychologists conducting cognitive research. Other contributing
fields include animal psychology, neuroscience, neuropharmacology,
and human neurophysiology.
Neuroimaging technologies such as CT, MRI, PET, and functional MRI have
revolutionized neuropsychology by providing insights into brain activity
and pathology. These imaging methods validate hypotheses about brain
function, aiding in diagnosis and treatment planning. A competent clinical
neuropsychologist should also be skilled in general psychology, enabling
effective patient interactions, assessments, and discussions of sensitive
medical information.
Functional Neuroanatomy
The human brain is highly complex, with structures relevant to
neuropsychology. Below is an overview of its key components:
Gross Structure of the Brain: Three major regions:
- Cerebral Hemispheres: Responsible for higher cognitive functions
and covered by the cerebral cortex (grey matter). White matter
beneath the cortex consists of axons connecting different brain regions.
Gyri (hills) & sulci (valleys)
, Cerebellar hemispheres: paired structures at base of hemispheres,
concerned with motor functions, muscle tone and balance
White matter: layer of axons that connect the nerve cells to rest of
the brain
- Brain Stem: Includes the medulla oblongata, pons, midbrain, and
diencephalon.- It controls vital functions like respiration and heart rate
but is not directly involved in higher cognition.
- Cerebellum: Essential for motor coordination, muscle tone, and
balance.
Other structures:
- Basal Ganglia: Deep grey matter structures involved in movement
regulation
- Longitudinal fissure: separates the 2 hemispheres
Other main fissures are: (central ( or Rolandic) fissure or sulcus:
seperates the frontal from the parietal lobe) & Corpus Callosum: A
fiber tract connecting the two hemispheres, enabling
interhemispheric communication.
Neural Pathways and Systems
- Reticular Formation (RF): Regulates cortical arousal levels and
alertness. Diffuse system of multisynaptic neuron chains traveling up
through brain stem
All major sensory pathways send impulses to RF, which relays them
to a group of nuclei in the:
- Thalamus: A relay center for sensory and motor pathways.
- Limbic System: Includes structures like the hippocampus and
amygdala, which are essential for memory, emotion, and motivation.
- Meninges: Three protective layers surrounding the brain (infection:
meningitis):
Dura Mater: The tough outermost layer.
Arachnoid Mater: The middle layer with a web-like structure.
Pia Mater: The delicate inner layer.
Ventricular and Cerebrovascular Systems
- Ventricles: lakes of cerebrospinal fluid (CSF)-filled cavities. CSF
circulates through the brain, cushioning it and removing waste.
Blockages can cause hydrocephalus, treatable with surgical valve or
shunts.
- Cerebrovascular system: Supplied by two main arterial systems:
Internal Carotid Arteries: Supply the anterior brain regions, 2
arteries enter skull and ascend on either side of optic chiasm: ACA &
MCA
Vertebral Arteries: Supply the posterior brain regions, merging into
the basilar artery.
Circle of Willis: A critical vascular network that compensates for
blockages. Weaknesses in its arteries can lead to aneurysms and
hemorrhages.
Stroke and Ischemia: Blocked arteries can deprive brain regions of
oxygen, causing strokes
, Venous System: Drains deoxygenated blood through cerebral veins
into the internal jugular vein.
Cerebral Cortex: Cortical Zones
The cerebral cortex can be divided into primary, secondary, and tertiary
zones, which help neuropsychologists understand the relationship between
anatomy and function. The cortex of each hemisphere is divided into these
zones for clarity.
1. Primary Zones: These areas process specific sensory information,
such as touch, sound, and vision, with each sensory modality
mapped to specific neurons. For example, a touch on the right index
finger is represented in the left hemisphere's primary sensory
cortex. Damage to these areas leads to specific sensory deficits,
such as loss of sensation or vision.
2. Secondary Zones: Also called the association cortex, these zones
are located adjacent to primary zones and are responsible for
integrating sensory information. Unlike primary zones, they do not
have a direct topographic relationship with sensory information.
Instead, they focus on perception and meaning, helping us
understand what we see, hear, or touch. Damage to these areas can
impair the ability to perceive or comprehend sensory information.
3. Tertiary Zones: Located at the borders of the parietal, temporal,
and occipital lobes, these areas are responsible for integrating
information across sensory modalities. Damage to tertiary zones can
result in complex cognitive disorders and may involve the limbic
system, which links emotion and memory to sensory experiences.
Frontal Lobes
The frontal lobes, located anterior to the central sulcus, are crucial for
action and executive functions. They can be divided into three zones:
1. Primary Motor Zone: Located on the precentral gyrus, it controls
voluntary movements with a topographical map of the body.
2. Secondary Zone: Known as the premotor cortex, this area
organizes motor patterns for activities like riding a bike.
3. Tertiary Zone (Prefrontal Cortex): This region is responsible for
executive functions such as planning, abstract thinking, and
emotional regulation. It interacts with the limbic system and
influences motivation and emotion.
Cortical Lobes
The brain is divided into four cortical lobes: frontal, parietal, temporal, and
occipital. These divisions are useful in understanding brain-behavior
relationships.
- Parietal Lobe: Involved in tactile sensation, spatial relations, and
calculations. The left hemisphere focuses on logical spatial abilities,
while the right hemisphere is more concerned with holistic spatial
awareness.
- Temporal Lobe: Primarily responsible for auditory and olfactory
functions, it also integrates sensory information and mediates memory.
, The left temporal lobe is involved in language comprehension and
verbal memory, while the right temporal lobe processes nonverbal
information, such as emotional cues in voices and music.
- Occipital Lobe: Responsible for visual perception, it processes sight
and visual knowledge. Damage to the primary visual cortex can result
in cortical blindness, while lesions in the association cortex can cause
conditions like visual agnosia, where a person cannot recognize what
they are seeing.
- Frontal Lobe: Concerned with motor functions and executive functions
such as planning and abstract thinking. The left frontal lobe includes
the speech area, Broca’s area, while the prefrontal cortex mediates
higher-level cognitive processes and emotional regulation. Damage to
the frontal lobes can lead to personality changes, memory deficits, and
impairments in executive functioning.
Functional Systems
Higher cognitive functions are not localized to specific areas but instead
involve networks of interconnected brain regions. A functional system is
composed of various brain areas that work together to produce a behavior.
Damage to one part of the system can lead to a range of behavioral
deficits. For instance, damage to the right parietal lobe can disrupt spatial
abilities, affecting tasks like solving puzzles or performing spatial
calculations.
Recovery from damage may involve the brain reorganizing itself, with
undamaged neurons compensating for lost functions. This could involve
rerouting connections or learning new ways to perform tasks.
Disconnection Syndrome
Disconnection syndromes arise when damage disrupts the connections
between brain areas. An example is ideomotor apraxia, where a patient
cannot perform skilled movements on command but can do so
spontaneously. This can occur due to damage to the arcuate fasciculus,
which connects the language comprehension area with motor areas.
Disconnection can also happen between hemispheres, such as in split-
brain patients who have undergone corpus callosotomy. These patients
may have difficulty naming objects seen by the right hemisphere, which
controls the left visual field. However, they can still respond to those
objects nonverbally using the left hand, showing that the right hemisphere
can comprehend language but cannot express it verbally.
Neuropsychological Terminology:
Deficit, Dysfunction, Symptom, Impairment, Disorder: These
terms are often used interchangeably to describe any abnormality in
motor, sensory, perceptual, behavioral, psychological, emotional, or
cognitive functioning.
Syndrome: A group of symptoms that typically occur together after
brain damage.
Aphasia, Graphia, Lexia, Apraxia, Gnosia: Terms referring to
disorders in speech (aphasia), writing (graphia), reading (lexia),
purposeful actions (praxis), and knowing (gnosis). Prefixes like "a-"
Chapter 1
A Definition of Clinical Neuropsychology and Its Aims
Clinical neuropsychology studies the relationship between human
behavior, emotions, and cognitive functions in relation to brain damage or
disorders. It serves both applied and academic purposes.
- The applied aspect focuses on diagnosing, treating, rehabilitating, and
preventing neurological disorders.
- Academically, it seeks to understand normal brain function by studying
cognitive impairments in brain-damaged individuals through controlled
experiments.
Relationship of Clinical Neuropsychology to Other Disciplines
Clinical neuropsychology overlaps with multiple disciplines:
- Neurology: Focuses on the medical aspects of central nervous system
disorders, including pathology and treatment.
- Cognitive Psychology: Aims to understand workings of human brain
by analyzing higher cognitive functions. Studies the functioning of the
mind through controlled cognitive experiments using unimpaired
participants.
- Cognitive Neuropsychology: A hybrid field that applies cognitive
psychology techniques to brain-damaged patients, primarily to
understand normal cognitive processes.
Clinical neuropsychology is positioned between neurology and cognitive
neuropsychology, integrating medical aspects of brain disorders with
higher cognitive function analysis.
- Some practitioners combine roles, such as behavioral neurologists or
neuropsychologists conducting cognitive research. Other contributing
fields include animal psychology, neuroscience, neuropharmacology,
and human neurophysiology.
Neuroimaging technologies such as CT, MRI, PET, and functional MRI have
revolutionized neuropsychology by providing insights into brain activity
and pathology. These imaging methods validate hypotheses about brain
function, aiding in diagnosis and treatment planning. A competent clinical
neuropsychologist should also be skilled in general psychology, enabling
effective patient interactions, assessments, and discussions of sensitive
medical information.
Functional Neuroanatomy
The human brain is highly complex, with structures relevant to
neuropsychology. Below is an overview of its key components:
Gross Structure of the Brain: Three major regions:
- Cerebral Hemispheres: Responsible for higher cognitive functions
and covered by the cerebral cortex (grey matter). White matter
beneath the cortex consists of axons connecting different brain regions.
Gyri (hills) & sulci (valleys)
, Cerebellar hemispheres: paired structures at base of hemispheres,
concerned with motor functions, muscle tone and balance
White matter: layer of axons that connect the nerve cells to rest of
the brain
- Brain Stem: Includes the medulla oblongata, pons, midbrain, and
diencephalon.- It controls vital functions like respiration and heart rate
but is not directly involved in higher cognition.
- Cerebellum: Essential for motor coordination, muscle tone, and
balance.
Other structures:
- Basal Ganglia: Deep grey matter structures involved in movement
regulation
- Longitudinal fissure: separates the 2 hemispheres
Other main fissures are: (central ( or Rolandic) fissure or sulcus:
seperates the frontal from the parietal lobe) & Corpus Callosum: A
fiber tract connecting the two hemispheres, enabling
interhemispheric communication.
Neural Pathways and Systems
- Reticular Formation (RF): Regulates cortical arousal levels and
alertness. Diffuse system of multisynaptic neuron chains traveling up
through brain stem
All major sensory pathways send impulses to RF, which relays them
to a group of nuclei in the:
- Thalamus: A relay center for sensory and motor pathways.
- Limbic System: Includes structures like the hippocampus and
amygdala, which are essential for memory, emotion, and motivation.
- Meninges: Three protective layers surrounding the brain (infection:
meningitis):
Dura Mater: The tough outermost layer.
Arachnoid Mater: The middle layer with a web-like structure.
Pia Mater: The delicate inner layer.
Ventricular and Cerebrovascular Systems
- Ventricles: lakes of cerebrospinal fluid (CSF)-filled cavities. CSF
circulates through the brain, cushioning it and removing waste.
Blockages can cause hydrocephalus, treatable with surgical valve or
shunts.
- Cerebrovascular system: Supplied by two main arterial systems:
Internal Carotid Arteries: Supply the anterior brain regions, 2
arteries enter skull and ascend on either side of optic chiasm: ACA &
MCA
Vertebral Arteries: Supply the posterior brain regions, merging into
the basilar artery.
Circle of Willis: A critical vascular network that compensates for
blockages. Weaknesses in its arteries can lead to aneurysms and
hemorrhages.
Stroke and Ischemia: Blocked arteries can deprive brain regions of
oxygen, causing strokes
, Venous System: Drains deoxygenated blood through cerebral veins
into the internal jugular vein.
Cerebral Cortex: Cortical Zones
The cerebral cortex can be divided into primary, secondary, and tertiary
zones, which help neuropsychologists understand the relationship between
anatomy and function. The cortex of each hemisphere is divided into these
zones for clarity.
1. Primary Zones: These areas process specific sensory information,
such as touch, sound, and vision, with each sensory modality
mapped to specific neurons. For example, a touch on the right index
finger is represented in the left hemisphere's primary sensory
cortex. Damage to these areas leads to specific sensory deficits,
such as loss of sensation or vision.
2. Secondary Zones: Also called the association cortex, these zones
are located adjacent to primary zones and are responsible for
integrating sensory information. Unlike primary zones, they do not
have a direct topographic relationship with sensory information.
Instead, they focus on perception and meaning, helping us
understand what we see, hear, or touch. Damage to these areas can
impair the ability to perceive or comprehend sensory information.
3. Tertiary Zones: Located at the borders of the parietal, temporal,
and occipital lobes, these areas are responsible for integrating
information across sensory modalities. Damage to tertiary zones can
result in complex cognitive disorders and may involve the limbic
system, which links emotion and memory to sensory experiences.
Frontal Lobes
The frontal lobes, located anterior to the central sulcus, are crucial for
action and executive functions. They can be divided into three zones:
1. Primary Motor Zone: Located on the precentral gyrus, it controls
voluntary movements with a topographical map of the body.
2. Secondary Zone: Known as the premotor cortex, this area
organizes motor patterns for activities like riding a bike.
3. Tertiary Zone (Prefrontal Cortex): This region is responsible for
executive functions such as planning, abstract thinking, and
emotional regulation. It interacts with the limbic system and
influences motivation and emotion.
Cortical Lobes
The brain is divided into four cortical lobes: frontal, parietal, temporal, and
occipital. These divisions are useful in understanding brain-behavior
relationships.
- Parietal Lobe: Involved in tactile sensation, spatial relations, and
calculations. The left hemisphere focuses on logical spatial abilities,
while the right hemisphere is more concerned with holistic spatial
awareness.
- Temporal Lobe: Primarily responsible for auditory and olfactory
functions, it also integrates sensory information and mediates memory.
, The left temporal lobe is involved in language comprehension and
verbal memory, while the right temporal lobe processes nonverbal
information, such as emotional cues in voices and music.
- Occipital Lobe: Responsible for visual perception, it processes sight
and visual knowledge. Damage to the primary visual cortex can result
in cortical blindness, while lesions in the association cortex can cause
conditions like visual agnosia, where a person cannot recognize what
they are seeing.
- Frontal Lobe: Concerned with motor functions and executive functions
such as planning and abstract thinking. The left frontal lobe includes
the speech area, Broca’s area, while the prefrontal cortex mediates
higher-level cognitive processes and emotional regulation. Damage to
the frontal lobes can lead to personality changes, memory deficits, and
impairments in executive functioning.
Functional Systems
Higher cognitive functions are not localized to specific areas but instead
involve networks of interconnected brain regions. A functional system is
composed of various brain areas that work together to produce a behavior.
Damage to one part of the system can lead to a range of behavioral
deficits. For instance, damage to the right parietal lobe can disrupt spatial
abilities, affecting tasks like solving puzzles or performing spatial
calculations.
Recovery from damage may involve the brain reorganizing itself, with
undamaged neurons compensating for lost functions. This could involve
rerouting connections or learning new ways to perform tasks.
Disconnection Syndrome
Disconnection syndromes arise when damage disrupts the connections
between brain areas. An example is ideomotor apraxia, where a patient
cannot perform skilled movements on command but can do so
spontaneously. This can occur due to damage to the arcuate fasciculus,
which connects the language comprehension area with motor areas.
Disconnection can also happen between hemispheres, such as in split-
brain patients who have undergone corpus callosotomy. These patients
may have difficulty naming objects seen by the right hemisphere, which
controls the left visual field. However, they can still respond to those
objects nonverbally using the left hand, showing that the right hemisphere
can comprehend language but cannot express it verbally.
Neuropsychological Terminology:
Deficit, Dysfunction, Symptom, Impairment, Disorder: These
terms are often used interchangeably to describe any abnormality in
motor, sensory, perceptual, behavioral, psychological, emotional, or
cognitive functioning.
Syndrome: A group of symptoms that typically occur together after
brain damage.
Aphasia, Graphia, Lexia, Apraxia, Gnosia: Terms referring to
disorders in speech (aphasia), writing (graphia), reading (lexia),
purposeful actions (praxis), and knowing (gnosis). Prefixes like "a-"
