Notes introductory psychology and brain and cognition
A brief history of cognitive neuroscience: important historical debates:
- Is there more to the mind than the brain alone?
o Monism: the brain produces behavior, thoughts and the mind (e.g., Thales,
Willis, La Mettrie, Gall). It’s your brain, nothing more. Materialism.
o Dualism: the mind appears from elsewhere; it is something immaterial (e.g.,
Descartes, “res cogitans” and “res extensa”)
Although cognitive neuroscience follows the monistic view, the debate continues:
if the mind is only material, can we build a conscious machine? Most cognitive
neuroscientists are monists.
Imagine only brain stuff that produces this thought. If you would have this
(knowledge of all biology parts) you can simulate it on the computer. But in this
case, people are doubting about monism.
- Does the brain work as one big organ or is it made up of different modules?
o Functional specialization (localization): different areas in the brain have
different functions (e.g., Willis, Gall’s phrenology) we do not have to refute it
but it is not true that we have bigger brain parts for certain skills.
o Aggregate Field Theory: the brain works as a whole (e.g., Flourens)
Much research is dedicated to finding “the neural correlate of cognitive
functions”, but no area works alone and research tries to unravel the networks
involved in cognition.
Study the brain to study behavior.
- Insights from neurophysiology and -anatomy:
o Electrical stimulation of brain areas produce characteristic movements in
dogs, it must therefore be specialized.
o Brodmann (1909): identification of 52 distinct brain areas with different
cellular architectures (cytoarchitectonics)
o Visualization of individual neurons by Golgi and Ramon y Cajal:
▪ Golgi: the cells in the brain form a continuous mass of tissue
(syncytium)
▪ Ramon y Cajal: the neural doctrine; neurons are discrete entities!
- The study of behavior/cognition:
o From empiricism and associationism to behaviorism. Empiricism: only have
knowledge from experience. No cognition without experience. All nurture.
o The cognitive revolution: Not all behavior is learned. Noam Chomsky:
behaviorism cannot explain everything: language: children come up with
sentences that they have never heard of.
,- The instruments of neuroscience: how to study cognition:
o Angelo Mosso (1891). Pulsation of the blood in the brain is
directly related to mental activity. Open up a scull and put the
device onto the brain. This device can measure blood flow. Let
them either rest or do a cognitive task. The pulsation goes up
when doing a mental activity.
- Structure and function of the nervous system
- The nervous system:
o Central Nervous system (CNS)
▪ Brain (cerebrum, cerebellum, brainstem)
▪ Spinal cord
o Peripheral nervous system (PNS)
▪ Nervous system that is not the Brain + Spinal Cord. All nerves coming
out of your spinal cord. Less interesting for cognitive neuroscientists.
- The cells of the nervous system:
o Two broad categories of cells in the nervous system:
▪ Neurons: to transmit information
▪ Glial cells: function depends on type. support neuro cells.
• Astrocytes – surround neurons and are in contact
with blood vessels. They create the blood-brain
barrier! Can also modulate neuronal activity.
• Oligodendrocytes – form myelin sheet around
neuron’s axons (electrical insulation). Speed
increases through insulation.
• Microglial cells – remove damaged cells
• Schwann cells – forms myelin sheet around
neuron’s axons (electrical insulation) in the PNS
- Neurons:
o Neuron is a typical eukaryotic cell with a cell
membrane that encases a cell body.
o The cell body (soma) is filled with cytoplasm, a
salty intracellular fluid, that suspends the
metabolic machinery (e.g., nucleus, ribosomes,
Golgi apparatus) that maintains the neuron.
o In addition to a cell body, a neuron also has
dendrites and an axon.
▪ Dendrites receive input from other neurons
, (at the dendritic spines).
▪ The axon outputs a signal to other neurons (at the axon terminals).
o A signal flows from the dendrites to the cell body to the axon. Electrical signal!
o 90 billion neurons
o They all have electrical signals this allows to study because of this signal
(magnetic field waves).
- Neural signaling:
o When a neuron is not sending a signal, it is
at rest. If you stick an electrode in the
neuron (with the extracellular space as a
reference), you will measure an electrical
voltage of -70mV. This is called the resting
membrane potential.
o The intra- (inside membrane), and
extracellular (outside membrane) fluid is
made up of a combination of ions (ions are atoms or molecules that have
either a positive or negative charge)
o Predominantly ions of:
▪ Potassium (K+)
▪ Sodium (Na+)
▪ Calcium (Ca2+)
▪ Chloride (Cl-)
▪ Arganic anions (A-)
o The intracellular fluid has more K + , the
extracellular space has more Na+
o The function of cell membranes is that there is a difference
between intra- and extracellular.
o Distribution is unequal.
o The cell membrane has transmembrane proteins that allow the
passing of ions:
▪ Ion channels: selectively permit one type of ion to pass. More
potassium (K+ ) channels in cell membrane.
▪ Ion pumps: active transport proteins. Sodium-potassium pump pumps
3 sodium ions (Na+ ) out of the cell and 2 potassium ions into the cell.
Requires energy!! Glucose and oxygen.
o The inside of a cell (the intracellular fluid) is separated from the outside (the
extracellular fluid) via a cell membrane.
o Intracellular fluid consists mostly of positively charged potassium
ions (K + ) and negatively charged organic anions (A- )
o Extracellular fluid consists mostly of positively charged sodium
ions (Na+ ) and negatively charged chloride ions (Cl- )
o The difference in the concentration (concentration gradient) of K+
, and Na+ inside and outside the cell is caused by the Na+ /K+ pump. This is an
enzyme that actively ‘pumps’ Na+ out of the cell and pumps K + inside the
cell. (There is a difference in concentration caused by the pump. It is an
enzyme that pumps).
o The cell membrane is mostly permeable to K+ (via potassium
channels). Because of the concentration gradient, K+ will move
from intra- to extracellular space. What will be the result:
potassium (K+) flows out going toward negative: less positive
inside and more negative outside.
o Because the other ions can’t move, an electrical imbalance arises
(more positively charged outside the cell)! Now there is an electrical gradient!
o At some point, the two opposing forces (the concentration gradient and the
electrical gradient) reach an electrochemical equilibrium state.
o In the equilibrium state, the difference in electrical charge is -70 mV (= resting
membrane potential)
- The action potential:
o When a neuron is active (i.e., when it is passing information) the resting
potential changes into an action potential. An action potential is the rapid
depolarization and repolarization on the neuron’s output.
o In the context of an action potential, depolarization and repolarization refer
to changes in the neuron's membrane potential (the difference in electrical
charge across its membrane) as it transmits a signal.
▪ Depolarization: At rest, a neuron has a negative membrane potential
(usually around -70mV), meaning the inside of the cell is more
negative than the outside. When a neuron receives a stimulus strong
enough to reach a threshold, voltage-gated sodium (Na⁺) channels
open, allowing Na⁺ ions to rush into the neuron. This inflow of positive
ions makes the inside of the cell more positive, rapidly increasing the
membrane potential (e.g., from -70mV up toward +30mV). This change
is called depolarization, as it reduces the polarity (difference in charge)
between the inside and outside of the neuron.
▪ Repolarization: After the peak of depolarization, sodium channels
close, and voltage-gated potassium (K⁺) channels open. K⁺ ions move
out of the neuron, restoring the inside of the cell to a more negative
charge. This return toward the resting membrane potential is called
repolarization. Repolarization helps reset the neuron so it can
potentially fire another action potential if stimulated again.
o A neuron receives a signal at the dendrites, more specifically on dendritic
spines.
o Dendritic spines contain channels that open when a neurotransmitter binds to
the channel receptor. If it fits with specific receptor, it will open up, only then
it will open up.
A brief history of cognitive neuroscience: important historical debates:
- Is there more to the mind than the brain alone?
o Monism: the brain produces behavior, thoughts and the mind (e.g., Thales,
Willis, La Mettrie, Gall). It’s your brain, nothing more. Materialism.
o Dualism: the mind appears from elsewhere; it is something immaterial (e.g.,
Descartes, “res cogitans” and “res extensa”)
Although cognitive neuroscience follows the monistic view, the debate continues:
if the mind is only material, can we build a conscious machine? Most cognitive
neuroscientists are monists.
Imagine only brain stuff that produces this thought. If you would have this
(knowledge of all biology parts) you can simulate it on the computer. But in this
case, people are doubting about monism.
- Does the brain work as one big organ or is it made up of different modules?
o Functional specialization (localization): different areas in the brain have
different functions (e.g., Willis, Gall’s phrenology) we do not have to refute it
but it is not true that we have bigger brain parts for certain skills.
o Aggregate Field Theory: the brain works as a whole (e.g., Flourens)
Much research is dedicated to finding “the neural correlate of cognitive
functions”, but no area works alone and research tries to unravel the networks
involved in cognition.
Study the brain to study behavior.
- Insights from neurophysiology and -anatomy:
o Electrical stimulation of brain areas produce characteristic movements in
dogs, it must therefore be specialized.
o Brodmann (1909): identification of 52 distinct brain areas with different
cellular architectures (cytoarchitectonics)
o Visualization of individual neurons by Golgi and Ramon y Cajal:
▪ Golgi: the cells in the brain form a continuous mass of tissue
(syncytium)
▪ Ramon y Cajal: the neural doctrine; neurons are discrete entities!
- The study of behavior/cognition:
o From empiricism and associationism to behaviorism. Empiricism: only have
knowledge from experience. No cognition without experience. All nurture.
o The cognitive revolution: Not all behavior is learned. Noam Chomsky:
behaviorism cannot explain everything: language: children come up with
sentences that they have never heard of.
,- The instruments of neuroscience: how to study cognition:
o Angelo Mosso (1891). Pulsation of the blood in the brain is
directly related to mental activity. Open up a scull and put the
device onto the brain. This device can measure blood flow. Let
them either rest or do a cognitive task. The pulsation goes up
when doing a mental activity.
- Structure and function of the nervous system
- The nervous system:
o Central Nervous system (CNS)
▪ Brain (cerebrum, cerebellum, brainstem)
▪ Spinal cord
o Peripheral nervous system (PNS)
▪ Nervous system that is not the Brain + Spinal Cord. All nerves coming
out of your spinal cord. Less interesting for cognitive neuroscientists.
- The cells of the nervous system:
o Two broad categories of cells in the nervous system:
▪ Neurons: to transmit information
▪ Glial cells: function depends on type. support neuro cells.
• Astrocytes – surround neurons and are in contact
with blood vessels. They create the blood-brain
barrier! Can also modulate neuronal activity.
• Oligodendrocytes – form myelin sheet around
neuron’s axons (electrical insulation). Speed
increases through insulation.
• Microglial cells – remove damaged cells
• Schwann cells – forms myelin sheet around
neuron’s axons (electrical insulation) in the PNS
- Neurons:
o Neuron is a typical eukaryotic cell with a cell
membrane that encases a cell body.
o The cell body (soma) is filled with cytoplasm, a
salty intracellular fluid, that suspends the
metabolic machinery (e.g., nucleus, ribosomes,
Golgi apparatus) that maintains the neuron.
o In addition to a cell body, a neuron also has
dendrites and an axon.
▪ Dendrites receive input from other neurons
, (at the dendritic spines).
▪ The axon outputs a signal to other neurons (at the axon terminals).
o A signal flows from the dendrites to the cell body to the axon. Electrical signal!
o 90 billion neurons
o They all have electrical signals this allows to study because of this signal
(magnetic field waves).
- Neural signaling:
o When a neuron is not sending a signal, it is
at rest. If you stick an electrode in the
neuron (with the extracellular space as a
reference), you will measure an electrical
voltage of -70mV. This is called the resting
membrane potential.
o The intra- (inside membrane), and
extracellular (outside membrane) fluid is
made up of a combination of ions (ions are atoms or molecules that have
either a positive or negative charge)
o Predominantly ions of:
▪ Potassium (K+)
▪ Sodium (Na+)
▪ Calcium (Ca2+)
▪ Chloride (Cl-)
▪ Arganic anions (A-)
o The intracellular fluid has more K + , the
extracellular space has more Na+
o The function of cell membranes is that there is a difference
between intra- and extracellular.
o Distribution is unequal.
o The cell membrane has transmembrane proteins that allow the
passing of ions:
▪ Ion channels: selectively permit one type of ion to pass. More
potassium (K+ ) channels in cell membrane.
▪ Ion pumps: active transport proteins. Sodium-potassium pump pumps
3 sodium ions (Na+ ) out of the cell and 2 potassium ions into the cell.
Requires energy!! Glucose and oxygen.
o The inside of a cell (the intracellular fluid) is separated from the outside (the
extracellular fluid) via a cell membrane.
o Intracellular fluid consists mostly of positively charged potassium
ions (K + ) and negatively charged organic anions (A- )
o Extracellular fluid consists mostly of positively charged sodium
ions (Na+ ) and negatively charged chloride ions (Cl- )
o The difference in the concentration (concentration gradient) of K+
, and Na+ inside and outside the cell is caused by the Na+ /K+ pump. This is an
enzyme that actively ‘pumps’ Na+ out of the cell and pumps K + inside the
cell. (There is a difference in concentration caused by the pump. It is an
enzyme that pumps).
o The cell membrane is mostly permeable to K+ (via potassium
channels). Because of the concentration gradient, K+ will move
from intra- to extracellular space. What will be the result:
potassium (K+) flows out going toward negative: less positive
inside and more negative outside.
o Because the other ions can’t move, an electrical imbalance arises
(more positively charged outside the cell)! Now there is an electrical gradient!
o At some point, the two opposing forces (the concentration gradient and the
electrical gradient) reach an electrochemical equilibrium state.
o In the equilibrium state, the difference in electrical charge is -70 mV (= resting
membrane potential)
- The action potential:
o When a neuron is active (i.e., when it is passing information) the resting
potential changes into an action potential. An action potential is the rapid
depolarization and repolarization on the neuron’s output.
o In the context of an action potential, depolarization and repolarization refer
to changes in the neuron's membrane potential (the difference in electrical
charge across its membrane) as it transmits a signal.
▪ Depolarization: At rest, a neuron has a negative membrane potential
(usually around -70mV), meaning the inside of the cell is more
negative than the outside. When a neuron receives a stimulus strong
enough to reach a threshold, voltage-gated sodium (Na⁺) channels
open, allowing Na⁺ ions to rush into the neuron. This inflow of positive
ions makes the inside of the cell more positive, rapidly increasing the
membrane potential (e.g., from -70mV up toward +30mV). This change
is called depolarization, as it reduces the polarity (difference in charge)
between the inside and outside of the neuron.
▪ Repolarization: After the peak of depolarization, sodium channels
close, and voltage-gated potassium (K⁺) channels open. K⁺ ions move
out of the neuron, restoring the inside of the cell to a more negative
charge. This return toward the resting membrane potential is called
repolarization. Repolarization helps reset the neuron so it can
potentially fire another action potential if stimulated again.
o A neuron receives a signal at the dendrites, more specifically on dendritic
spines.
o Dendritic spines contain channels that open when a neurotransmitter binds to
the channel receptor. If it fits with specific receptor, it will open up, only then
it will open up.
