Brain Organisation and Cognition for Behavioural Scientists
Week 1 - Neuroanatomy
Lecture Video 1 – Introduction to Human Brain Anatomy
Studies of human behavior are often combined with studies of human brain function. To
understand and interpret the resulting data, it is important to know the underlying basics of
human neuroanatomy.
The main biological specimens used to understand human brain structure and function
relationships are rodents. substantial differences in the gross anatomy of the brain between
the two thus it’s unlikely that studies in rodents can be translated directly to the human
situation and thus studies in rodents require the replication of the results in humans.
An increasing number of neuroimaging techniques is available for studying human brain
function. So what is the anatomical backbone that gives rise to the signals we detect with
fMRI, EEG, PET etc...?
1. The human brain
The human brain is convoluted (verwickelt, zusammengerollt) with bulges (called gyri) and
spaces (called sulci). Prominent sulci are the Sylvian Fissure and the Central sulcus.
This model represents an ideal situation. Although the general features of human anatomy are
very consistent there are a lot of variations in its appearance and the main features are often
hard to recognize.
, 2. Components of the brain
The signal measured in studies on the human brain is often interpreted as a measure for
neuronal function, but there are also other components of the brain which can give rise to the
measured signal or interfere with the signal interpreted by the researchers.
Thus, in addition to neurons, of which we have several types in the brain and which form
complex networks, we also have several types of Glia cells in the brain.
General outline of the majority of neurons in the human brain.
Input is received via the dendrite and output signals are sent via the synaptic output terminal.
In the brain, the neurons are surrounded by glia cells. They are smaller than neurons and
closely connect. There are several distinct types of glia cells: Microglia, Astrocytes,
Oligodendrocytes, Ependymal cells, Schwann cells (peripheral nerve system).
,Microglia
Microglia are phagocytotic cells, which means that they clean up. One feature of the
microglial cells is that they are not static in shape.
On the left: Microglial cell in a healthy situation (at rest)
On the right: cell that has retracted its processes and has acquired a rounded shape (activated
microglial cell).
Activated microglia are hypothesized to give rise to MRI differences as observed in the
substantia nigra of Parkinson’s patients. changes that we can observe in brain function
studies can potentially result from other sources (not neurons).
Astrocytes
Originally it was thought that these cells exist solely to provide structural and functional
support to neurons. Now we know that they are also involved in the processing of
information in the brain. They control the microenvironment around the neurons, provide
structural integrity and are important in maintaining the blood brain barrier. They also
actively convert and activate or inactivate hormones for instance.
Oligodendrocytes
Oligodendrocytes are large glial cells, which are also found in the central nervous system.
They produce the myelin sheath which insulates the neuronal axons (see image above). The
Myelin producing cells form from 4 months of gestation until the 2nd decade of life and one
oligodendrocyte myelinates many axons.
Schwann cells serve a similar function as oligodendrocytes, but in the peripheral nervous
system.
Some oligodendrocytes are not involved in the myelination of neurons. Those are called
satellite oligodendrocytes.
Given that behavioral studies in literature often use data from young students, it is important
to realize that the anatomy of those young students may not be fully representative of the
adult situation yet.
, So when measuring behavior in patient groups and comparing those to healthy individuals,
does everyone have a comparable brain structure? And what type of variation is present
within the groups of the tested samples? One extreme example:
Multiple sclerosis – the demyelinating disease
This disease causes lesions inside the brain (in their white matter). This disease can exist for a
long time.
On the image: white spots represent those lesions. These lesions are not in the same place for
every patient with MS, which means that their brains will all be affected in different ways.
This is likely to be reflected in differences in behavior as well, which complicates the
comparison of patient groups with healthy individuals.
Ependymocytes
Ependymocytes are specialized glial cells which line the ventricular cavities and the central
canal of the spinal cord.
Important: There are many subtypes of brain cells, which allow an even more detailed
description of human brain anatomy. All of these subtypes may influence the signal
differently as compared to other subtypes when performing brain studies with common
techniques such as fMRI and EEG, and usually it’s not clear which brain components
together give rise to the signal.
How do these components combined form the brain?
Week 1 - Neuroanatomy
Lecture Video 1 – Introduction to Human Brain Anatomy
Studies of human behavior are often combined with studies of human brain function. To
understand and interpret the resulting data, it is important to know the underlying basics of
human neuroanatomy.
The main biological specimens used to understand human brain structure and function
relationships are rodents. substantial differences in the gross anatomy of the brain between
the two thus it’s unlikely that studies in rodents can be translated directly to the human
situation and thus studies in rodents require the replication of the results in humans.
An increasing number of neuroimaging techniques is available for studying human brain
function. So what is the anatomical backbone that gives rise to the signals we detect with
fMRI, EEG, PET etc...?
1. The human brain
The human brain is convoluted (verwickelt, zusammengerollt) with bulges (called gyri) and
spaces (called sulci). Prominent sulci are the Sylvian Fissure and the Central sulcus.
This model represents an ideal situation. Although the general features of human anatomy are
very consistent there are a lot of variations in its appearance and the main features are often
hard to recognize.
, 2. Components of the brain
The signal measured in studies on the human brain is often interpreted as a measure for
neuronal function, but there are also other components of the brain which can give rise to the
measured signal or interfere with the signal interpreted by the researchers.
Thus, in addition to neurons, of which we have several types in the brain and which form
complex networks, we also have several types of Glia cells in the brain.
General outline of the majority of neurons in the human brain.
Input is received via the dendrite and output signals are sent via the synaptic output terminal.
In the brain, the neurons are surrounded by glia cells. They are smaller than neurons and
closely connect. There are several distinct types of glia cells: Microglia, Astrocytes,
Oligodendrocytes, Ependymal cells, Schwann cells (peripheral nerve system).
,Microglia
Microglia are phagocytotic cells, which means that they clean up. One feature of the
microglial cells is that they are not static in shape.
On the left: Microglial cell in a healthy situation (at rest)
On the right: cell that has retracted its processes and has acquired a rounded shape (activated
microglial cell).
Activated microglia are hypothesized to give rise to MRI differences as observed in the
substantia nigra of Parkinson’s patients. changes that we can observe in brain function
studies can potentially result from other sources (not neurons).
Astrocytes
Originally it was thought that these cells exist solely to provide structural and functional
support to neurons. Now we know that they are also involved in the processing of
information in the brain. They control the microenvironment around the neurons, provide
structural integrity and are important in maintaining the blood brain barrier. They also
actively convert and activate or inactivate hormones for instance.
Oligodendrocytes
Oligodendrocytes are large glial cells, which are also found in the central nervous system.
They produce the myelin sheath which insulates the neuronal axons (see image above). The
Myelin producing cells form from 4 months of gestation until the 2nd decade of life and one
oligodendrocyte myelinates many axons.
Schwann cells serve a similar function as oligodendrocytes, but in the peripheral nervous
system.
Some oligodendrocytes are not involved in the myelination of neurons. Those are called
satellite oligodendrocytes.
Given that behavioral studies in literature often use data from young students, it is important
to realize that the anatomy of those young students may not be fully representative of the
adult situation yet.
, So when measuring behavior in patient groups and comparing those to healthy individuals,
does everyone have a comparable brain structure? And what type of variation is present
within the groups of the tested samples? One extreme example:
Multiple sclerosis – the demyelinating disease
This disease causes lesions inside the brain (in their white matter). This disease can exist for a
long time.
On the image: white spots represent those lesions. These lesions are not in the same place for
every patient with MS, which means that their brains will all be affected in different ways.
This is likely to be reflected in differences in behavior as well, which complicates the
comparison of patient groups with healthy individuals.
Ependymocytes
Ependymocytes are specialized glial cells which line the ventricular cavities and the central
canal of the spinal cord.
Important: There are many subtypes of brain cells, which allow an even more detailed
description of human brain anatomy. All of these subtypes may influence the signal
differently as compared to other subtypes when performing brain studies with common
techniques such as fMRI and EEG, and usually it’s not clear which brain components
together give rise to the signal.
How do these components combined form the brain?
