Simulation and mirror neurons. Evidence in humans and monkeys


Term Paper (Advanced seminar), 2011

13 Pages, Grade: 1,7


Excerpt

Table of Contents

Abstract

1. Introduction

2. Simulation Theory

3. Mirror neurons as the neural correlate of mind-reading
3.1. Mirror neurons in monkeys and humans
3.2. Mirror neurons and mind-reading

4. Conclusions

5. References

Abstract

In the last years there has been evidence for a special class of neurons. These so-called mirror neurons are located in the premotor cortex of monkeys and equally show activity during the performance and the observation of particular actions. Some authors interpret this function as the neural correlate of mind-reading, the ability to attribute mental states to others. Furthermore this interpretation is valued as support to a particular theory of mind theory; simulation theory, which claims that we understand the intentions, beliefs and emotions of others by simulating their mental processes on the basis of our own. In this paper I will review evidence for mirror neurons being the neural correlate of mind-reading. To accomplish this I will also review evidence for mirror neurons in monkeys and humans and give a short outline of simulation theory.

1. Introduction

How do we understand others? By which means do we get knowledge of their emotions, intentions, beliefs and desires? There are several different approaches trying to explain how this so-called mind-reading is achieved. Mind-reading compromises the evaluation of mental states of others like beliefs, desires or intentions and the attribution of mental states to another person.[1] One predominant example is the simulation theory (ST). ST is an approach which tries to explain our ability to make sense of other people´s behavior. In short this theory claims that we simulate the mental states of others by using our own mental processes as a manipulable model.[2] Furthermore the neural correlate of mind-reading is being investigated.[3]

Recently a new class of neurons in the brains of monkeys has been discovered. These so-called mirror neurons (MNs) are active both when the monkeys perform a certain action and when they observe another monkey performing the same action.[4] Several other studies claim that a similar mirroring system in the human brain exists. Whether the evidence for such a mirroring system in humans is convincing is still a matter of debate.[5] Some researchers have suggested that those mirroring systems are the neural correlate of mind-reading in humans and monkeys.[6] Furthermore this correlation is interpreted as a support for ST.[7] [8] In this paper I want to review evidence in favor of and against those ideas.

First of all I will give a brief account of ST in order to provide some philosophical context for the following part, which considers empirical studies on MN. After this I will present and criticize some evidence for the existence of MNs in monkeys and humans. Then I will present some evidence which is interpreted as support for the thesis that MNs are the neural correlate of mind-reading in humans and monkeys. Finally I will try and criticize this interpretation of the given evidence in order to see whether it is justified.

2. Simulation Theory

The ST is one of the predominant accounts of our ability to mind-read others. ST claims that we use our own mind as a basis for understanding others. The approach assumes that we use our own mind as a model to simulate the mental states of others.[9] As Goldman puts it:

“… the fundamental idea of mental simulation is that mind readers go about their task by putting themselves, imaginatively, in a target´s mental ´shoes`.”[10] ST is understood to be ´process-driven´. This means the output of the simulation is generated with little or no influence from general information about minds.[11]

According to Goldman the simulation routine involves three consequent steps.[12] When trying to understand what another person feels or intends we first create pretend mental states like beliefs or desires in ourselves that are supposed to match the mental states of this person. For example when playing a game one could create the pretend desire that the opponent wants to win the game and the pretend belief that a certain strategy would be helpful for this. Secondly we feed these pretend states into our own mental processing, for example the decision-making or emotion-generating mechanism. But as those mechanisms are in this case only used for simulation, the output of this processing is taken ´off-line´, as it is only used to predict or explain the targets behavior. This means the output isn´t fed into our own action control system, but into our behavior-predicting and –explaining system. Finally we assign the output state of our own mental processing to the other person. To be successful the pretend beliefs and desires have of course to be sufficiently similar to those of the target.[13] The following figure illustrates the described simulation routine:

Abbildung in dieser Leseprobe nicht enthalten[14]

Goldman and Gallese believe that MNs form the neural basis for this simulation routine or are at least a precursor of mind-reading.[15] In what follows I will review and criticize evidence and arguments supporting this interpretation.

3. Mirror neurons as the neural correlate of mind-reading

3.1. Mirror neurons in monkeys and humans

Several studies have recently proved the existence of a particular type of visuomotor neurons in the brains of monkeys.[16] These so-called mirror neurons are located in a particular area of the monkey´s brain, the premotor cortex. What is special about these neurons is that they are not only active while the monkey performs a certain action, but also whilst it observes another monkey or even human performing the same action. The highest activity of MNs can be found for motor actions, like grasping, and the observation of such movements.[17] Due to single cell recording during action execution and observation proof of the existence of MNs in monkeys is quite substantial.[18]

Whether there is a comparable mirroring system in humans is still a matter of debate. The problem with all evidence concerning such a system in humans is the lack of direct measurement due to the lack of single cell recordings. As far as humans are concerned this deficiency of course results out of ethical reasoning. In an extensive review of several studies Turella and colleagues[19] try to answer the question whether there is satisfying evidence for a mirror system in humans, which sufficiently resembles the one found in monkeys. They come to the conclusion that there is no compelling evidence of such a mirror system to this date. This lack of evidence is according to them at least partly caused by the fact that there are currently no studies that duplicate the exact conditions under which the studies with monkeys were performed.[20] Gallese and Goldman on the other hand claim that there is at least evidence strongly suggesting the existence of a mirror system in humans, which is similar to the one found in monkeys.[21] First they refer to one study using Transcranic Magnetic Stimulation (TMS) by Fadiga and colleagues[22]. In this study the motor cortex of normal subjects was stimulated under four conditions. The subjects observed an experimenter grasping 3D-objects, looked at the same 3D-objects, observed an experimenter tracing geometrical figures in the air with his arm, and detected the dimming of a light. Fadiga and colleagues found that Motor Evoked Potentials (MEPs) significantly increased while the subjects observed the experimenters movements and came to the conclusion that there is a system matching action observation and execution in humans.[23] Secondly Gallese and Goldman refer to two studies with a similar experimental design using Positron Emission Tomography (PET) that were run by Rizzolati[24] and Grafton[25]. In both studies PET was used to demonstrate which brain areas are active while subjects perform certain tasks. In the first study normal subjects observed an experimenter grasping objects, grasped the same objects themselves and observed objects as a control task. The findings showed that action observation activates certain brain areas, which in the opinion of the authors show functional homologies to the brain areas that play a role in MN activity in monkeys.[26] In the second study subjects observed an experimenter grasping objects under the first condition, imagined to grasp these objects themselves without actually doing it and again observed objects as a comparable control task. The findings showed that grasp observation and imagined grasping activate different brain areas.[27]

[...]


[1] Newen 2009, p. 216.

[2] Cruz/Gordon 2003, p. 10.

[3] Gallese/ Goldman 1998, p. 495.

[4] Gallese/Goldman 1998, p. 493.

[5] Turella et al. 2009.

[6] Gallese/ Goldman 1998, p. 495.

[7] Gallese/Goldman 1998.

[8] Gallese 2007.

[9] Gordon 1986, p. 165.

[10] Goldman 2005, p. 86.

[11] Cruz/Gordon 2003, p. 10.

[12] Goldman 2005, p. 80-81.

[13] Gallese/Goldman 1998, p. 496-497.

[14] Gallese/Goldman 1998, p. 497.

[15] Gallese/Goldman 1998; Goldman 2005.

[16] Gallese/Goldman 1998.

[17] Gallese/Goldman 1998.

[18] Rizzolatti 2004.

[19] Turella et al. 2009.

[20] Turella et al. 2009, p. 18.

[21] Gallese/Goldman 1998, p. 495.

[22] Fadiga et al. 1995.

[23] Fadiga et al. 1995, p. 2608.

[24] Rizzolatti et al. 1996.

[25] Grafton et al. 1996.

[26] Rizzolatti et al. 1996, p. 246.

[27] Grafton et al. 1996, p. 103.

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Details

Title
Simulation and mirror neurons. Evidence in humans and monkeys
College
University of Dusseldorf "Heinrich Heine"  (Institut für Philosophie)
Course
Philosophy of Neuroscience
Grade
1,7
Author
Year
2011
Pages
13
Catalog Number
V180662
ISBN (eBook)
9783656035435
ISBN (Book)
9783656035176
File size
593 KB
Language
English
Tags
Spiegelneuronen, mirror neurons, Neurowissenschaften, neuro science, Fremdpsychisches, other mind, Simulationstheorie, simulation theory, theory of mind, mindreading, Philosophie des Geistes, philosophy of mind, Simulation, social cognition, Soziale Kognition
Quote paper
B.A. Nicolas Lindner (Author), 2011, Simulation and mirror neurons. Evidence in humans and monkeys, Munich, GRIN Verlag, https://www.grin.com/document/180662

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