Behavioural Neurosciences
LECTURE 1 CHAPTER 1&7 P. 180-193 ~ VAN DER ZEE
Some misconceptions about the brain:
1. We only use a part of our brain. Nonsense, we use all our neurons actively to some extent;
long-term inactive neurons die due to a lack of neurotrophic factors.
2. Starting at the age of 25 neurons die progressively; at high age large numbers of neurons
are gone. Incorrect, recently developed methods for cell counting have shown that in case
of healthy, non-demented elderly only limited loss of neurons occurs (max. 5%).
3. After birth and the first years of brain development no new neurons are being born in the
brain. Incorrect; in at least three brain regions production of new neurons (neurogenesis)
still takes place at all ages, although the production is rather low at high age.
Nervous system: Brain, spinal cord and nerves of the body. In the past people were boring holes in
each other’s skulls – trepanation (to cure).
Hippocrates, the father of Western medicine, believed that the brain was not only involves in
sensation but was also the seat of intelligence. Aristotle believes it was the hart, and thought that
the heart was a radiator for cooling blood.
Cerebrum (front): soft, must received sensations, perceptions and memories, largest part. Consist of
cerebral hemispheres, separated by the deep sagittal fissure, the right receives sensations from, and
controls movements of the left side of the body. Figure 7.4B
Cerebellum (back): hard, must command the muscles, left side controls movement of the left.
~ thoughts from Galen, Bell.
Andreas Vesalius added more detail to the structure of the brain.
Descartes: thought the brain is not only responsible for human behavior, it controlled only human
behavior that is like that of the beasts. Figure 1.8
Nerves as Wires: In 1751, nerves conduct electrical signals
to and from the brain by the movement of fluid.
Before the nerves attach to the spinal cord, the fibers
divide into two branches, or roots. The dorsal root enters
toward the back of the spinal cord, and the ventral root
enters toward the front. Figure 1.9.
Transmission is strictly in one way!
Experimental ablation method: parts of the brain are systematically destroyed to determine their
functions, Flourens did this too animals.
Phrenology: new science of correlating the structure of the head with personality traits, Gall.
Paul Broca: tilting the scales of scientific opinion firmly toward localization of functions in the
cerebrum. He saw a men that could understand language but couldn’t speak it, this was
because his lesion in the left frontal lobe, (responsible for the production of speech).
Cognitive neuroscience: neural mechanisms responsible for the higher levels of human
mental activity like imagination and language.
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,Motor aphasia; if you cannot speak properly, like what Broca saw, they
understand languages.
Sensory aphasia; if you do not understand language (dyslexia), Spoken
language of Wernicke patients usually sounds fluently, but lacks meaning
(it doesn’t make sense).
the direction toward the rat’s tail is posterior or caudal, through the head is called rostral. The
direction pointing up is known as dorsal, direction pointing down is ventral.
So the rad spinal cord goes rostral to caudal, or anterior to posterior.
Bilateral symmetry: the right side of the brain and spinal cord is the mirror image of the left side.
Ipsilateral: two structures that are on the same side are this.
Contralateral: structures on the opposite side are this. Figure 7.3!
The brain stem: best observed in a midsagittal view of the brain. It is a complex nexus of fibers and
cells that in part serves to relay information from the cerebrum to the spinal cord and cerebellum.
And It is a side where vital functions like breathing are regulated.
The spinal cord: attached to the brain stem, it is the major conduit of information from the skin,
joints and muscles of the body to the brain and vice versa. It communicates with the body via the
spinal nerves, it exit the spinal cord through notches between each vertebra (inkeping) of the
vertebral column. Each spinal nerve attaches to the spinal cord by means of two branches, the dorsal
root contain axons (information into) and the ventral root contain axons (information away), F.7.5.
Peripheral nervous system: all the parts of the nervous system other than the brain and spinal cord.
• Somatic PNS: under voluntary control, the somatic motor axons derive from motor neurons
in the ventral spinal cord. The cell bodies often in CNS, but their axons are mostly in the PNS.
The somatic sensory axons, enter the spinal cord via the dorsal roots. The cell bodies lie
outside the spinal cord in clusters called dorsal root ganglia
• Visceral PNS: involuntary or autonomic nervous system, regulate the internal organs, blood
vessels and glands. Visceral sensory axons bring information about visceral function to the
CNS, such as oxygen content. Visceral motor fibers command the contraction and relaxation
of muscles that form the walls of the intestines and blood vessels.
Afferent: carry to (sensory axons)/Efferent: carry from (to innervate the muscles).
There are 12 pairs of cranial nerves that arise from the brain stem and innervate mostly the head.
The dura mater (outer), the arachnoid membrane (middle, spiderweb) and the pia mater (close to
brain), also called the meninges are membranes that protect the CNS. Between the arachnoid and
pia is a subarachnoid space with salty clear liquid called cerebrospinal fluid CSF.
The fluid-filled caverns and canals inside the brain constitute the ventricular system. This fluid is CSF
it is produced by choroid plexus in the ventricles of cerebral hemispheres. It flows from the paired
ventricles of the cerebrum to a series of connected central cavities at the core of the brain stem.
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,CSF is absorbed by the blood vessels at special structures called arachnoid villi.
CLARITY: visualization of deep structures without sectioning the
brain, but soak in a solution that replaces light-absorbing lipids
with a water-soluble gel that turns the brain transparent. And than
neurons with green fluorescent protein GFP figure 7.8
Water in the brain: if the flow of CSF from the choroid plexus
through the ventricular system to the subarachnoid space is impaired,
the fluid will back up and cause a swelling of the ventricles, this is called
hydrocephalus, mostly in babies. In adults it is more serious because the skull can’t expand.
Treatment: setting a tube into the swollen ventricle and draining off the excess fluid.
Electromagnetic radiation, like X-rays, are absorbed by various radiopaque tissues, this make 2D
images of the bones of the skull, not for the brain. But CT can do it, an X-ray source is rotated around
the head withing the plane of the desired cross section. On the other side of the head, in the
trajectory of the X-ray beam, are sensitive electronic sensors of X-irradiation.
Magnetic resonance imaging MRI: the advantages of MRI are that it yields a much more detailed
map of the brain, it has information about how hydrogen atoms in the brain respond to
perturbations (verstoringen) of a strong magnetic field. The key is to making protons jump from one
state to the other. The electromagnetic signals emitted by the atoms are detected by an array of
sensors around the head. A technique that can be used for determining the amount of certain atoms
at different locations in the body. PAGE 189!
Diffusion tensor imaging DTI, enables visualization of large bundles of axons in the brain, the water
diffusion can be measured. Water diffuses much more readily alongside axon membranes than
across them.
Positron emission tomography PET, it detect changes in regional blood flow and metabolism within
the brain. Neurons that are active demand more glucose and oxygen, the brain vasculature responds
to neural activity by blood flow, PET reveal the regions of brain that are most active under different
circumstances. This is also functional magnetic resonance imaging fMRI. PAGE 190!
In a study by Neuroscientist Dr. James Fallon, it was revealed that while a normal
brain shows patches of yellow and red when scanned, a psychopath’s brain has
dark patches, which suggest low activity in the orbital cortex, an area of the brain
responsible for moral decision-making. An inactive orbital cortex cannot control
the amygdala, which dictates aggression.
De grijze stof (buitenkant) is het deel van het centrale zenuwstelsel dat de
cellichamen van de zenuwcellen, de dendrieten en de korte axonen bevat. De
witte stof is het deel dat de lange, gemyeliniseerde axonen bevat.
Production CSF about 500 ml/dag
Volume ventricles about 150 ml
Replacement of CSF about 3 times/day
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, LECTURE 2 C HAPTER 2 ~ VAN DER ZEE
Neurophilosophy: the neuron as basic unit which can be studied by neuroanatomical techniques.
Microtome: make very thin slices of the brain, they can harden or fix tissues by immersing them in
formaldehyde.
Histology: is the microscopic study of the structure of tissues.
Analysis of brain material: Nissl staining (Franz Nissl), he showed that a class of basic dyes would
stain the nuclei of all cells as well as clumps (Nissl bodies) of material surrounding the nuclei of
neurons.
• Distinguishes between neurons and glia (connective tissue)
• Enables histologist to study the arrangement, or cytoarchitecture of neurons in different
parts of the brain.
Golgi staining (Camillo Golgi) Rival of Nissl; nevertheless a joint Noble price. He discovered that
soaking brain tissue in a silver chromate solution, called the Golgi stain, makes a small percentage of
neurons become darkly colored in their entirety. This shows that the neuron cell body a very small
part is of the neuron.
The swollen region has more names: cell body, soma and perikaryon. Thin tubes: neurites and are
two types: axons (long ~ 1m) and dendrites (short ~ 2mm).
Golgi: championed the view that the neurites of different cells are fused together to form a
continuous reticulum or network similar to the arteries and veins.
Cajal: argued forcefully that the neurites of different neurons are not continuous with each other and
communicate by contact, not continuity. This idea that cell theory also applies to neurons is named
neuron doctrine. Dendrites and axons belong to one soma/neuron.
Soma 20 mM : the roughly spherical central part of the neuron. There in is a salty potassium rich
solution called cytosol.
Nucleus 5-10 mM: it is contained within a double membrane called the nuclear envelope.
BLZ 30 afb kennen!
The axon begins with a region called the axon hillock. Two features distinguish the axon
from the soma:
• No rough ER extends into the axon, and there are few if any free ribosomes in
mature axons.
• The protein composition of the axon membrane is fundamentally different from
that of the soma membrane.
Axon collaterals: axon branches. Recurrent collaterals: an axon collateral returns to
communicate with the same cell that give rise to the axon.
The thicker the axon the faster the impulse travels.
The axon end with a region called the axon terminal or terminal bouton. This is the site where the
axon comes in contact with other neurons and passes formation on them. The point of contact is
called the synapse.
Terminal arbor: are branches at their ends and each branch forms a synapse on dendrites or cell
bodies in the same region.
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