Mismatch negativity
Encyclopedia
The mismatch negativity (MMN) or mismatch field (MMF) is a component of the event-related potential
(ERP) to an odd stimulus in a sequence of stimuli. It arises from electrical activity in the brain
and is studied within the field of cognitive neuroscience
and psychology
. It can occur in any sensory system, but has most frequently been studied for audition
and for vision
. In the case of auditory stimuli, the MMN occurs after an infrequent change in a repetitive sequence of sounds (sometimes the entire sequence is called an oddball sequence.) For example, a rare deviant (d) sound can be interspersed among a series of frequent standard (s) sounds (e.g., s s s s s s s s s d s s s s s s d s s s d s s s s...). The deviant sound can differ from the standards in one or more perceptual features such as pitch
, duration, or loudness
. The MMN can be elicited regardless of whether the subject is paying attention to the sequence. During auditory sequences, a person can be reading or watching a silent subtitled movie, yet still show a clear MMN. In the case of visual stimuli, the MMN occurs after an infrequent change in a repetitive sequence of images.
MMN refers to the mismatch response in electroencephalography
(EEG); MMF or MMNM refer to the mismatch response in magnetoencephalography
(MEG).
, A. W. K. Gaillard, and S. Mäntysalo at the Institute for Perception, TNO
in The Netherlands.
The first report of a visual MMN was in 1990 by Rainer Cammer. For a history of the development of the visual MMN, see Pazo-Alvarez et al. (2003).
The auditory MMN can occur in response to deviance in pitch, intensity, or duration. The auditory MMN is a fronto-central negative potential with sources in the primary and non-primary auditory cortex and a typical latency of 150-250 ms after the onset of the deviant stimulus. Sources could also include one from the right opercular part of the inferior frontal gyrus
. The amplitude and latency of the MMN is related to how different the deviant stimulus is from the standard. Large deviances elicit MMN at earlier latencies. For very large deviances, the MMN can even overlap the N100 (e.g., Campbell et al., 2007).
The visual MMN can occur in response to deviance in such aspects as color, size, or duration. The visual MMN is an occipital negative potential with sources in the primary visual cortex
and a typical latency of 150-250 ms after the onset of the deviant stimulus.
perception, to test whether or not these participants neurologically distinguish between certain kinds of sounds. In addition to these kinds of studies focusing on phonological
processing, some research has implicated the MMN in syntactic
processing. Some of these studies have attempted to directly test the automaticity of the MMN, providing converging evidence for the understanding of the MMN as a task-independent and automatic response.
Presently, the accumulated body of evidence suggests that while the MMN offers unique opportunities to basic research of the information processing of a healthy brain, it might be useful in tapping neurodegenerative changes as well.
MMN, which is elicited irrespective of attention, provides an objective means for evaluating possible auditory discrimination and sensory-memory anomalies in such clinical groups as dyslexics and patients with aphasia, who have a multitude of symptoms including attentional problems. Recent results suggest that a major problem underlying the reading deficit in dyslexia might be an inability of the dyslexics' auditory cortex to adequately model complex sound patterns with fast temporal variation. According to the results of an ongoing study, MMN might also be used in the evaluation of auditory perception deficits in aphasia.
AD patients demonstrate decreased amplitude of MMN, especially with long inter-stimulus intervals; this is thought to reflect reduced span of auditory sensory memory. Parkinsonian patients do demonstrate a similar deficit pattern, whereas alcoholism would appear to enhance the MMN response. This latter, seemingly contradictory, finding could be explained by hyperexcitability of CNS neurones resulting from neuroadaptive changes taking place during a heavy drinking bout.
While the results obtained thus far seem encouraging, several steps need to be taken before the MMN can be used as a clinical tool in patient treatment. A focus of research in the late 1990s aimed to tackle some of the key signal-analysis problems encountered in development of clinical use of MMN and challenges still remain. Nevertheless, as it stands, clinical research employing the MMN has already produced significant knowledge on the CNS functional changes related to cognitive decline in the aforementioned clinical disorders.
A 2010 study found that MMN durations were reduced in a group of schizophrenia patients who later went on to have psychotic episodes, suggesting that MMN durations may predict future psychosis.
Integral to this memory trace view is that there are:
i) a population of sensory afferent neuronal elements that respond to sound, and;
ii) a separate population of memory neuronal elements that build a neural model of standard stimulation and respond more vigorously when the incoming stimulation violates that neural model, eliciting an MMN.
An alternative "fresh afferent" interpretation (Näätänen, 1992; Jääskeläinen et al., 2004) is that there are no memory neuronal elements, but the sensory afferent neuronal elements that are tuned to properties of the standard stimulation respond less vigorously upon repeated stimulation. Thus when a deviant activates a distinct new population of neuronal elements that is tuned to the different properties of the deviant rather than the standard, these fresh afferents respond more vigorously, eliciting an MMN.
A third view is that the sensory afferents are the memory neurons (Ulanovsky, 2004; Jääskeläinen et al., 2007).
Event-related potential
An event-related potential is any measured brain response that is directly the result of a thought or perception. More formally, it is any stereotyped electrophysiological response to an internal or external stimulus....
(ERP) to an odd stimulus in a sequence of stimuli. It arises from electrical activity in the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
and is studied within the field of cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...
and psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
. It can occur in any sensory system, but has most frequently been studied for audition
Audition
An audition is a sample performance by an actor, singer, musician, dancer or other performing artist.Audition may also refer to:* The sense of hearing* Adobe Audition, audio editing software...
and for vision
Visual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
. In the case of auditory stimuli, the MMN occurs after an infrequent change in a repetitive sequence of sounds (sometimes the entire sequence is called an oddball sequence.) For example, a rare deviant (d) sound can be interspersed among a series of frequent standard (s) sounds (e.g., s s s s s s s s s d s s s s s s d s s s d s s s s...). The deviant sound can differ from the standards in one or more perceptual features such as pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...
, duration, or loudness
Loudness
Loudness is the quality of a sound that is primarily a psychological correlate of physical strength . More formally, it is defined as "that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud."Loudness, a subjective measure, is often...
. The MMN can be elicited regardless of whether the subject is paying attention to the sequence. During auditory sequences, a person can be reading or watching a silent subtitled movie, yet still show a clear MMN. In the case of visual stimuli, the MMN occurs after an infrequent change in a repetitive sequence of images.
MMN refers to the mismatch response in electroencephalography
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...
(EEG); MMF or MMNM refer to the mismatch response in magnetoencephalography
Magnetoencephalography
Magnetoencephalography is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using arrays of SQUIDs...
(MEG).
History
The auditory MMN was discovered in 1978 by Risto NäätänenRisto Näätänen
Risto Kalervo Näätänen, born 1939, is a modern Finnish psychologist and neuroscientist, member of the Finnish Academy of Science, Professor in University of Helsinki 1975-1999, one of the few Finnish scientists who have been appointed permanent Academy Professors of the Academy of Finland...
, A. W. K. Gaillard, and S. Mäntysalo at the Institute for Perception, TNO
Netherlands Organisation for Applied Scientific Research
Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek or TNO is a not-for-profit organization in the Netherlands that focuses on applied science. The main office of TNO is located in Delft...
in The Netherlands.
The first report of a visual MMN was in 1990 by Rainer Cammer. For a history of the development of the visual MMN, see Pazo-Alvarez et al. (2003).
Characteristics
The MMN is a response to a deviant within a sequence of otherwise regular stimuli; thus, in an experimental setting, it is produced when stimuli are presented in a many-to-one ratio; for example, in a sequence of sounds s s s s s s s d s s s s d s s s..., the d is the deviant or oddball stimulus, and will elicit an MMN response. The mismatch negativity occurs even if the subject is not consciously paying attention to the stimuli. Processing of sensory stimulus features is essential for humans in determining their responses and actions. If behaviourally relevant aspects of the environment are not correctly represented in the brain, then the organism's behaviour cannot be appropriate. Without these representations our ability to understand spoken language, for example, would be seriously impaired. Cognitive neuroscience has consequently emphasised the importance of understanding brain mechanisms of sensory information processing, that is, the sensory prerequisites of cognition. Most of the data obtained, unfortunately, do not allow the objective measurement of the accuracy of these stimulus representations (see Näätänen, 1992). In audition, recent cognitive neuroscience seems to have succeeded in extracting such a measure, however. This is the mismatch negativity (MMN), a component of the event-related potential (ERP), first reported by Näätänen, Gaillard, and Mäntysalo (1978). An in-depth review of MMN research can be found in Näätänen (1992) while other recent reviews also provide information on the generator mechanisms of MMN (Alho 1995), its magnetic counterpart, MMNm (Näätänen, Ilmoniemi & Alho, 1994), and its clinical applicability (Näätänen & Alho, 1995).The auditory MMN can occur in response to deviance in pitch, intensity, or duration. The auditory MMN is a fronto-central negative potential with sources in the primary and non-primary auditory cortex and a typical latency of 150-250 ms after the onset of the deviant stimulus. Sources could also include one from the right opercular part of the inferior frontal gyrus
Inferior frontal gyrus
The inferior frontal gyrus is a gyrus of the frontal lobe . It is labelled gyrus frontalis inferior, its Latin name...
. The amplitude and latency of the MMN is related to how different the deviant stimulus is from the standard. Large deviances elicit MMN at earlier latencies. For very large deviances, the MMN can even overlap the N100 (e.g., Campbell et al., 2007).
The visual MMN can occur in response to deviance in such aspects as color, size, or duration. The visual MMN is an occipital negative potential with sources in the primary visual cortex
Visual cortex
The visual cortex of the brain is the part of the cerebral cortex responsible for processing visual information. It is located in the occipital lobe, in the back of the brain....
and a typical latency of 150-250 ms after the onset of the deviant stimulus.
Neurolinguistics of MMN
As kindred phenomena have been elicited with speech stimuli, under passive conditions that require very little active attention to the sound, a version of MMN has been frequently used in studies of neurolinguisticNeurolinguistics
Neurolinguistics is the study of the neural mechanisms in the human brain that control the comprehension, production, and acquisition of language. As an interdisciplinary field, neurolinguistics draws methodology and theory from fields such as neuroscience, linguistics, cognitive science,...
perception, to test whether or not these participants neurologically distinguish between certain kinds of sounds. In addition to these kinds of studies focusing on phonological
Phonology
Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
processing, some research has implicated the MMN in syntactic
Syntax
In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....
processing. Some of these studies have attempted to directly test the automaticity of the MMN, providing converging evidence for the understanding of the MMN as a task-independent and automatic response.
The MMN for Basic Stimulus Features
MMN is evoked by an infrequently presented stimulus ("deviant"), differing from the frequently-occurring stimuli ("standards") in one or several physical parameters like duration, intensity, or frequency (Näätänen, 1992). In addition, it is generated by a change in spectrally complex stimuli like phonemes, in synthesised instrumental tones, or in the spectral component of tone timbre. Also the temporal order reversals elicit an MMN when successive sound elements differ either in frequency, intensity, or duration. The MMN is not elicited by stimuli with deviant stimulus parameters when they are presented without the intervening standards. Thus, the MMN has been suggested to reflect change detection when a memory trace representing the constant standard stimulus and the neural code of the stimulus with deviant parameter(s) are discrepant.MMN vs Auditory Sensory Memory
The MMN data can be understood as providing evidence that stimulus features are separately analysed and stored in the vicinity of auditory cortex (for a discussion, please see the theory section below). The close resemblance of the behaviour of the MMN to that of the previously behaviourally observed "echoic" memory system strongly suggests that the MMN provides a non-invasive, objective, task-independently measurable physiological correlate of stimulus-feature representations in auditory sensory memory.Relationship to Attentional Processes
The experimental evidence suggests that the auditory sensory memory index MMN provides sensory data for attentional processes, and, in essence, governs certain aspects of attentive information processing. This is evident in the finding that the latency of the MMN determines the timing of behavioural responses to changes in the auditory environment. Furthermore, even individual differences in discrimination ability can be probed with the MMN. The MMN is also a likely component of the chain of brain events causing attention switches to changes in the environment. In the light of these observations, it seems that at present the MMN provides the best available physiological measure of automatic central auditory processing.MMN in clinical research
The MMN has been documented in a number of studies to disclose neuropathological changes.Presently, the accumulated body of evidence suggests that while the MMN offers unique opportunities to basic research of the information processing of a healthy brain, it might be useful in tapping neurodegenerative changes as well.
MMN, which is elicited irrespective of attention, provides an objective means for evaluating possible auditory discrimination and sensory-memory anomalies in such clinical groups as dyslexics and patients with aphasia, who have a multitude of symptoms including attentional problems. Recent results suggest that a major problem underlying the reading deficit in dyslexia might be an inability of the dyslexics' auditory cortex to adequately model complex sound patterns with fast temporal variation. According to the results of an ongoing study, MMN might also be used in the evaluation of auditory perception deficits in aphasia.
AD patients demonstrate decreased amplitude of MMN, especially with long inter-stimulus intervals; this is thought to reflect reduced span of auditory sensory memory. Parkinsonian patients do demonstrate a similar deficit pattern, whereas alcoholism would appear to enhance the MMN response. This latter, seemingly contradictory, finding could be explained by hyperexcitability of CNS neurones resulting from neuroadaptive changes taking place during a heavy drinking bout.
While the results obtained thus far seem encouraging, several steps need to be taken before the MMN can be used as a clinical tool in patient treatment. A focus of research in the late 1990s aimed to tackle some of the key signal-analysis problems encountered in development of clinical use of MMN and challenges still remain. Nevertheless, as it stands, clinical research employing the MMN has already produced significant knowledge on the CNS functional changes related to cognitive decline in the aforementioned clinical disorders.
A 2010 study found that MMN durations were reduced in a group of schizophrenia patients who later went on to have psychotic episodes, suggesting that MMN durations may predict future psychosis.
Theory
The mainstream "memory trace" interpretation of MMN is that it is elicited in response to violations of simple rules governing the properties of information. It is thought to arise from violation of an automatically formed, short-term neural model or memory trace of physical or abstract environmental regularities (Näätänen & Winkler, 1999; Näätänen, Paavilainen, Rinne, & Alho 2007). However, other than MMN, there is no other neurophysiological evidence for the formation of the memory representation of those regularities.Integral to this memory trace view is that there are:
i) a population of sensory afferent neuronal elements that respond to sound, and;
ii) a separate population of memory neuronal elements that build a neural model of standard stimulation and respond more vigorously when the incoming stimulation violates that neural model, eliciting an MMN.
An alternative "fresh afferent" interpretation (Näätänen, 1992; Jääskeläinen et al., 2004) is that there are no memory neuronal elements, but the sensory afferent neuronal elements that are tuned to properties of the standard stimulation respond less vigorously upon repeated stimulation. Thus when a deviant activates a distinct new population of neuronal elements that is tuned to the different properties of the deviant rather than the standard, these fresh afferents respond more vigorously, eliciting an MMN.
A third view is that the sensory afferents are the memory neurons (Ulanovsky, 2004; Jääskeläinen et al., 2007).
See also
- Somatosensory evoked potentialSomatosensory Evoked PotentialSomatosensory Evoked Potentials are a useful, noninvasive means of assessing somatosensory system functioning. By combining SEP recordings at different levels of the somatosensory pathways, it is possible to assess the transmission of the afferent volley from the periphery up to the cortex...
- C1 and P1C1 & P1 (Neuroscience)The C1 and P1 are two human scalp-recorded event-related brain potential components, collected by means of a technique called electroencephalography . The C1 is named so because it was the first component in a series of components found to respond to visual stimuli when it was first discovered...
- Visual N1Visual N1The Visual N1 is a visual evoked potential, a type of event-related electrical potential , that is produced in the brain and recorded on the scalp. The N1 is so named to reflect the polarity and typical timing of the component. The "N" indicates that the polarity of the component is negative with...
- N100
- N200N200 (neuroscience)The N200, or N2, is an event-related potential component. An ERP can be monitored using a non-invasive electroencephalography cap that is fitted over the scalp on human subjects...
- N2pcN2pcN2pc refers to an ERP component linked to selective attention. The N2pc appears over visual cortex contralateral to the location in space to which subjects are attending; if subjects pay attention to the left side of the visual field, the N2pc appears in the right hemisphere of the brain, and...
- N170N170The N170 is a component of the event-related potential that reflects the neural processing of faces.When potentials evoked by images of faces are compared to those elicited by other visual stimuli, the former show increased negativity 130-200 ms after stimulus presentation...
- P200P200In neuroscience, the visual P200 or P2 is a waveform component or feature of the event-related potential measured at the human scalp. Like other potential changes measurable from the scalp, this effect is believed to reflect the post-synaptic activity of a specific neural process...
- N400
- P300 (neuroscience)P300 (neuroscience)The P300 wave is an event related potential elicited by infrequent, task-relevant stimuli. It is considered to be an endogenous potential as its occurrence links not to the physical attributes of a stimulus but to a person's reaction to the stimulus. More specifically, the P300 is thought to...
- P3aP3aThe P3a, or novelty P3, is a component of time-locked signals known as event-related potentials . The P3a is a positive-going scalp-recorded brain potential that has a maximum amplitude over frontal/central electrode sites with a peak latency falling in the range of 250-280 ms...
- P3bP3bThe P3b is a subcomponent of the P300, an event-related potential component that can be observed in human scalp recordings of brain electrical activity...
- Late Positive ComponentLate Positive ComponentThe LPC is a positive-going event-related brain potential component that has been important in studies of explicit recognition memory...
- Difference due to MemoryDifference due to MemoryDifference due to Memory indexes differences in neural activity during the study phase of an experiment for items that subsequently are remembered compared to items that are later forgotten...
- Contingent negative variationContingent negative variationThe contingent negative variation was one of the first event-related potential components to be described. The CNV component was first described by Dr. W. Grey Walter and colleagues in an article published in Nature in 1964...
- Error-related negativityError-related negativityError-related negativity , , is a component of an event-related potential . ERPs are electrical activity in the brain as measured through electroencephalography and time-locked to an external event...
- BereitschaftspotentialBereitschaftspotentialIn neurology, the Bereitschaftspotential or BP , also called the pre-motor potential or readiness potential , is a measure of activity in the motor cortex of the brain leading up to voluntary muscle movement. The BP is a manifestation of cortical contribution to the pre-motor planning of volitional...
- Lateralized readiness potentialLateralized readiness potentialIn neuroscience, the lateralized readiness potential is an event-related brain potential, or increase in electrical activity at the surface of the brain, that is thought to reflect the preparation of motor activity on a certain side of the body; in other words, it is a spike in the electrical...
- Early left anterior negativityEarly left anterior negativityThe early left anterior negativity is an event-related potential in electroencephalography , or component of brain activity that occurs in response to a certain kind of stimulus...
- P600P600The P600 is an event-related potential , or peak in electrical brain activity measured by electroencephalography . It is a language-relevant ERP and is thought to be elicited by hearing or reading grammatical errors and other syntactic anomalies...
- Oddball paradigmOddball paradigmThe oddball paradigm is a technique used in evoked potential research in which trains of stimuli that are usually auditory or visual are used to assess the neural reactions to unpredictable but recognizable events...
External links
- Mismatch Negativity (MMN) summary at the Cognitive Brain Research Unit at the University of Helsinki