Flip the classroom: Shedding light on consciousness, emotions and understanding others

Question 1

What are advantages and disadvantages of EEG and fMRI?

Answer 1

• EEG only measures signals on the surface of the brain, but has good temporal resolution.
• fMRI measures signals from deep brain structures, but does not have good temporal resolution.

Question 2

What are disadvantages of using invasive techniques in animals?

Answer 2

That you cannot study human cognition

Question 3

So what became possible in humans (or: what technological breakthrough was there for researching the brain in humans)?

Answer 3

Intracranial recordings became possible

Question 4

Herbert Jasper invented the Montreal procedure for patients with severe epilepsy. He operated these patients by destroying nerve cells in the brain where the seizure originated. What did he do before operating (i.e. the Montreal procedure)?

Answer 4

Before operating, he stimulated the brain with electrical probes while the patients were conscious on the operating table, and observed their responses. In this way he could more accurately target the areas of the brain responsible, reducing the side-effects of the surgery.

Question 5

Just look at the cortical representation of the body.

Answer 5

Ok

Question 6

What three types of electrodes are used today and where are they placed in the brain during surgery?

Answer 6

1. Subdural array: direct on the surface of the cortex
2. Utah array: intracortical electrodes (usual too small for surgery)
3. Depth electrodes: deep structures in the brain

Question 7

Describe the brain process in an epileptic patient.

Answer 7

Epilepsy is where the balance of inhibition and excitation is disturbed, which results in giant synchronous discharges almost everywhere in the brain or in part of the brain.

Question 8

Why are deep brain electrodes used for characterisation of where seizures arise from in the brain?

Answer 8

Because with the use of deep electrodes, you can measure almost all the activity in the brain. EEG or fMRI are not precise enough for this.

Question 9

What is used for planning where the electrodes will be placed in the brain?

Answer 9

MRI, so that the surgeon knows where critical areas are (with blood vessels and structures that can’t be damaged).

Question 10

Deep brain electrodes are used for clinical purposes. But deep brain electrodes can be combined with something else to also use it for research. What can be used for this?

Answer 10

Fried-Behnke electrodes can be added to the deep brain electrodes. These are micro wires that are able to record the signals as small as single action potentials of individual cells.

Question 11

A patient that gets treated for epilepsy needs to be monitored for 2 week in the hospital. What is monitored?

Answer 11

Brain activity and video surveillance to closely watch seizures when they arise. Also tiny experiments can be performed.

Question 12

• What is measured with the clinical deep brain electrodes?
• What is measured using the Fried-Behnke electrodes (micro-wires)?

Answer 12

• Local field potentials can be measured with the clinical electrodes.
• Single cell recordings are made with the micro wires to measure single action potentials.

Question 13

Just know that these electrodes can also stimulate certain parts of the brain, where you can measure what reaction the patients gives to this stimulation. This can be done for (I think) scientific purposes.

Answer 13

Ok

Question 14

What are advantages of intracranial recordings?

Answer 14

• High spatial resolution
• High temporal resolution
• High signal-to-noise ratio
• Broad spatial distribution (electrodes simultaneously in multiple brain regions)
• Cognition can be tested in humans

Question 15

What are limitations of intracranial recordings?

Answer 15

• Subject population can only be patients with pathologies of the brain
• Individual variation between subjects
• Researcher can not choose subjects, timing or brain area.

Question 16

What is the Jennifer Aniston cell?

Answer 16

The concept that a specific single neuron can be activated by a single concept, like Jennifer Aniston.

Question 17

What happens if you present a stimuli (e.g. picture of Jan Smit) for very short intervals of time?

Answer 17

The subject only recognizes a small proportion of the images.

Question 18

By progressively shortening the duration of stimulus presentation, the researchers show two striking properties of these neurons. What?

Answer 18

1. Their responses are not statistically different for the first 33-, 66- and 132-ms stimulus durations, but only for the 264-ms presentations there’s a significantly higher firing.
2. These responses follow conscious perception. Remarkably, when recognized, a single snapshot as brief as 33 ms was sufficient to trigger strong single-unit responsess far outlasting stimulus presentation.

Question 19

What brain region are responsible for detecting consciously perceived stimuli?

Answer 19

Neurons in medial temporal lobe (MTL)

Question 20

(Experiment not discussed in the lecture) Another research was performed where the researchers were interested in the emotional perception of recognized and unrecognized words in amygdala. They asked the question if the amygdala is activated by non-consciously perceived threatening stimuli. What did they do in their research and what was the conclusion?

Answer 20

They presented threatening words (“danger”) or neutral words (“cousin”) in masked trials (where the stimulus is presented too short to be recognized ) or in unmasked trials (where the stimuli are visible to be recognized). The conclusion was that in masked and unmasked trials, the cells in the amygdala still could recognize the emotional meaning.

Question 21

What is the old view of perceiving the action of others?

Answer 21

That perceiving the action of others comes from a process somewhere inbetween visual processing and motor programs.

Question 22

What was discovered that established a new view of perceiving the action of others?

Answer 22

The discovery of mirror neurons in the premotor cortex, important for observation and reaction.

Question 23

How were mirror neurons discovered?

Answer 23

An experiment where apes got electrode implantations to measure single unit recordings. The researchers were interested in goal-directed behaviour, specifically how activity develops when an ape decides and grabs food of a plate.

Question 24

What was found during this experiment?

Answer 24

They found that when the monkey is considering grabbing the food, there’s already one single/specific neuron that fires. And when the monkey actually picks up the food, this same neuron spikes again.

Question 25

So what are mirror neurons?

Answer 25

Neurons that are activated by observation and execution of the same motion or emotion.

Question 26

Fill in: They found that …% of all motor neurons are mirror neurons.

Answer 26

They found that 10% of all motor neurons are mirror neurons.

Question 27

What are space-sensitive mirror neurons?

Answer 27

Mirror neurons specific for encoding actions in prepersonal or extrapersonal space.

Question 28

What are value-senstivie mirror neurons?

Answer 28

Mirror neurons that are influenced by the type of observed grasped object (food vs. no value), 70% of all mirror neurons are value-sensitive.

Question 29

Where can mirror neurons be found in monkeys? Is it the same for humans?

Answer 29

In monkeys, mirror neurons are found in the intraparietal sulcus (IPS) and areas of the inferior parietal lobule (PF/PFG). In humans there are mirror neurons found during fMRI studies, in the same kind of brain areas as of the monkeys.

Question 30

What kind of rhythm is displayed during rest (of the motor cortex), so if you don’t perform any action, in EEG?

Answer 30

Mu rhythm (it’s the same as alpha oscillations arise when closing your eyes when in resting state), these oscillations break up when you start performing an action.

Question 31

So what happens to the mu rhythm:

• when doing nothing?
• when performing an action?
• when observing others performing that same action?

Answer 31

• when doing nothing –> there’s mu activity
• when performing an action, the mu rhythm is suppressed.
• when observing others performing that same action, the mu rhythm will also be suppressed, although not as strongly as when performing the task yourself.

Question 32

The EEG and fMRI results provide the idea that humans have mirror neurons, but the results are not enough to establish this. What experiment can be performed?

Answer 32

Performing an experiment where subjects are asked to look at pictures of people frowning or smiling (observation) and after this are asked to frown or smile themselves. This experiment can also be done with hand/finger movement (observing someone else grabbing something vs grabbing something yourself).

Question 33

What was the conclusion of this experiment where we wanted to know whether mirror neurons exist in humans?

Answer 33

That mirror neurons exist.

Picture A shows a single neuron located in the supplementary motor area that fires itself when either observing or performing a hand/finger movement, but isn’t responsive to facial expressions.

Picture B shows a single neuron located in the entorhinal cortex that fires during observation and execution of facial expressions, but not during hand/finger movement.

Question 34

Just know that these mirror neurons can also react as mirror neurons by inhibiting their activity. Like a single neuron in the sensory-motor cortex that decreases its firing rate during smile execution and observation.

Answer 34

Ok

Question 35

How many mirror neurons (%) are there in the human brain?

Answer 35

8%, but it depends on the brain area.

Question 36

So what function do mirror neurons probably have?

Answer 36

Because of mirror neurons, we have empathy and can understand the emotion of others.

Question 37

Which areas are important for emotional processing?

Answer 37

Cortical areas (like the insular cortex that is important for noticing how your body feels), thalamus, subcortical structures.

Question 38

How can you measure the activity of the insular cortex?

Answer 38

By showing videos of people drinking something which is either very nice to drink (pleasure), ok to drink (neutral) or very disgusting to drink.

Question 39

What is seen when you measure the activity of the insular cortex?

Answer 39

That when perceiving other peoples’ disgust or content, the insular cortex is activated. And even, when someone scored high on empathy, their insular activity was higher compared to others that didn’t have so much empathy.

Question 40

What clinical implications of mirror systems is there?

Answer 40

Autism and psychopaths.

Question 41

What is shown in the mirror systems of autistic patients?

Answer 41

In this picture, the mu supression was measured by letting controls and autistic patients observe an action (ball, hand) and then performing that action. What they saw was that the mu suppression went up in both groups when performing the action. But that there’s almost no mu supression in autistic patients when observing the action.

Question 42

An experiment was performed where the brain activity of control and psychopaths was measured during observation of certain hand movement/touches and the amount of empathy they felt was also measured. What did they saw?

Answer 42

That during observation, psychopaths show lower activation in certain areas in comparison with controls. And psychopaths show higher activation of certain brain areas in comparison with control when looked at empathy. So the conclusion is that psychopaths can feel empathy when they want to, but when observing something empathy is not something that just gets activated.