Summary Neuronal Networks and Behaviours
Lecture 1, Introduction lecture
What do we know about the world?
How can we know anything about the outside world?
- Our 5 senses
But do we see the world the way it really is?
• A shark:
– Hears its prey at >1 km or more
– Smells its prey at >100 m
– ‘Feels’ its prey up to 100 m away
– Perceives electrical activity of its prey 50 cm away
– Tastes its prey before ingesting it, using taste receptors on surface of the face
– Only ever sees a blurry image at near range
Every animal constructs a view of the world through its brain and senses (for their particular
way of life)
Can we trust our senses?
Do our senses show us anything?
,The brain is a prediction machine. It is playing movies in our head of what we think is out
there.
Are we our brain?
- It largely constructs the Image we have of the outside world
- Our brain gets only a limited view of reality outside us
- Our brain creates predictions, expectations and interpretations
Does that mean we are ‘just’ our brain?
Our nervous system is interconnected with our body (not separate)
... the brain is embedded in our body...
And... we have many more senses:
• Sight
• Taste
• Touch
• Smell
• Hearing
• Pressure
• Itch
• Thermoception
• Proprioception
• Tension sensors
• Nociception
• Equilibrioception
• Stretch Receptors
• Chemoreceptors
• Thirst
• Hunger
• Magnetoception
• Time
• ...
,Perception
Neural mechanisms of the sensory systems:
• Receptor neurons
• The anatomical pathways
• Representation in the brain
Movement
How does brain react to the world?
• Lower motor neurons initiating muscle contractions
• Upper motor neurons planning and initiating movement
• Filtering and modulating loops (basal ganglia and cerebellum)
Cognition and emotion
What happens in between sensing and reacting?
• Attention
• Cognition
• Memory
• Emotion
Levels of organization
, How does the brain work?
- The human brain is built of neurons (densely packed)
- The human cortex:
• >86 billion neurons (more than stars in the universe)
• 1000-10.000 synapses per neuron
• 10 14- 10 15 synapses
Communication between neurons: synaptic transmission
What happens is when an action potential arrives in the axon it polarizes the membrane. Due
to this depolarization voltage-gated calcium channels will be activated, once activated they
open and calcium comes into the cell. This calcium can trigger neurotransmitter release by
the fusion of the vesicle with the membrane. The neurotransmitter will bind to its receptor
on the postsynaptic neuron and activate different cascades of reactions depending on the
kind of receptor and neurotransmitter.
Pyramidal cells have this name because of their shape, they have a lot of dendrites with
many spines, which are specialized protrusions that are able to receive information from
axon boutons. Axon boutons come from different cells and release neurotransmitters onto
postsynaptic receptors. Moreover, this cell has elaborate axons.
In the cell body with patch clamp cell recording, we can measure depolarization and
hyperpolarization.
Lecture 1, Introduction lecture
What do we know about the world?
How can we know anything about the outside world?
- Our 5 senses
But do we see the world the way it really is?
• A shark:
– Hears its prey at >1 km or more
– Smells its prey at >100 m
– ‘Feels’ its prey up to 100 m away
– Perceives electrical activity of its prey 50 cm away
– Tastes its prey before ingesting it, using taste receptors on surface of the face
– Only ever sees a blurry image at near range
Every animal constructs a view of the world through its brain and senses (for their particular
way of life)
Can we trust our senses?
Do our senses show us anything?
,The brain is a prediction machine. It is playing movies in our head of what we think is out
there.
Are we our brain?
- It largely constructs the Image we have of the outside world
- Our brain gets only a limited view of reality outside us
- Our brain creates predictions, expectations and interpretations
Does that mean we are ‘just’ our brain?
Our nervous system is interconnected with our body (not separate)
... the brain is embedded in our body...
And... we have many more senses:
• Sight
• Taste
• Touch
• Smell
• Hearing
• Pressure
• Itch
• Thermoception
• Proprioception
• Tension sensors
• Nociception
• Equilibrioception
• Stretch Receptors
• Chemoreceptors
• Thirst
• Hunger
• Magnetoception
• Time
• ...
,Perception
Neural mechanisms of the sensory systems:
• Receptor neurons
• The anatomical pathways
• Representation in the brain
Movement
How does brain react to the world?
• Lower motor neurons initiating muscle contractions
• Upper motor neurons planning and initiating movement
• Filtering and modulating loops (basal ganglia and cerebellum)
Cognition and emotion
What happens in between sensing and reacting?
• Attention
• Cognition
• Memory
• Emotion
Levels of organization
, How does the brain work?
- The human brain is built of neurons (densely packed)
- The human cortex:
• >86 billion neurons (more than stars in the universe)
• 1000-10.000 synapses per neuron
• 10 14- 10 15 synapses
Communication between neurons: synaptic transmission
What happens is when an action potential arrives in the axon it polarizes the membrane. Due
to this depolarization voltage-gated calcium channels will be activated, once activated they
open and calcium comes into the cell. This calcium can trigger neurotransmitter release by
the fusion of the vesicle with the membrane. The neurotransmitter will bind to its receptor
on the postsynaptic neuron and activate different cascades of reactions depending on the
kind of receptor and neurotransmitter.
Pyramidal cells have this name because of their shape, they have a lot of dendrites with
many spines, which are specialized protrusions that are able to receive information from
axon boutons. Axon boutons come from different cells and release neurotransmitters onto
postsynaptic receptors. Moreover, this cell has elaborate axons.
In the cell body with patch clamp cell recording, we can measure depolarization and
hyperpolarization.
