7 Computational EEG Analysis for the Diagnosis of Psychiatric …
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two constructs can be assumed when considering the serotonin system as a mediator.
Therefore, more studies examining LDAEP as a candidate of clinical markers for
sensitivity and impulsivity demand greater clinical attention.
7.2.4 The 40-Hz Auditory Steady-State Response
The 40-Hz auditory steady-state response (ASSR) measures oscillatory responses
following auditory stimulation at gamma-band frequency [130]. Gamma-band oscillations play an important role in establishing temporal precisions in local cortical
networks [133], and are candidate mechanisms of perceptual integration, attentional
selection, and working memory [116, 133]. Because of its importance in a variety
of cognitive functions, abnormal gamma oscillations have been actively studied in
schizophrenia and bipolar disorder, which include a wide set of cognitive and perceptual anomalies as their primary symptoms [98, 100, 112].
Abnormal gamma oscillations are a critical element in current disease models of
schizophrenia, including N-methyl-d-aspartate (NMDA) receptor hypofunction and
altered excitation and inhibition balance models. Indeed, the generation of gamma
oscillations has been shown to depend on the integrity of neural circuits involving fast-spiking parvalbumin-expressing cells, and the hypofunction of the NMDA
receptor on these interneurons has been suspected to underlie psychosis [29, 55, 77].
Importantly, pharmacological and genetic animal studies imply that mechanisms
of gamma oscillation generation are relatively well-articulated and may converge
across species, rendering gamma oscillation, and consequently the 40-Hz ASSR a
potentially promising target of translational research [88].
7.2.5 Mismatch Negativity
Mismatch negativity (MMN) is an automatically generated ERP component when a
sequence of relatively uniform stimuli is interrupted by the infrequent presentation
of deviant stimuli. Initially discovered in an auditory experimental procedure, MMN
is thought to reflect an automated detection of perceptual change or a sensory prerequisite of cognition and has been closely examined in relation to attentional processes
[94]. In particular, the MMN latency defines the response time change in the sensory
stimulus [131].
Although MMN can occur in any sensory system, it has been most frequently
studied in the visual and the auditory systems. In the case of auditory stimuli, MMN
occurs after an infrequent change in a repetitive sequence of sounds. The deviant
sound can differ from the standards in one or more perceptual features such as pitch,
duration, or loudness. In addition, MMN is usually evoked either by a change in
frequency, intensity, duration, and by apparent spatial locus of origin. Deficiency
in MMN appears to be an index of cognitive decline, irrespective of the specific
153
two constructs can be assumed when considering the serotonin system as a mediator.
Therefore, more studies examining LDAEP as a candidate of clinical markers for
sensitivity and impulsivity demand greater clinical attention.
7.2.4 The 40-Hz Auditory Steady-State Response
The 40-Hz auditory steady-state response (ASSR) measures oscillatory responses
following auditory stimulation at gamma-band frequency [130]. Gamma-band oscillations play an important role in establishing temporal precisions in local cortical
networks [133], and are candidate mechanisms of perceptual integration, attentional
selection, and working memory [116, 133]. Because of its importance in a variety
of cognitive functions, abnormal gamma oscillations have been actively studied in
schizophrenia and bipolar disorder, which include a wide set of cognitive and perceptual anomalies as their primary symptoms [98, 100, 112].
Abnormal gamma oscillations are a critical element in current disease models of
schizophrenia, including N-methyl-d-aspartate (NMDA) receptor hypofunction and
altered excitation and inhibition balance models. Indeed, the generation of gamma
oscillations has been shown to depend on the integrity of neural circuits involving fast-spiking parvalbumin-expressing cells, and the hypofunction of the NMDA
receptor on these interneurons has been suspected to underlie psychosis [29, 55, 77].
Importantly, pharmacological and genetic animal studies imply that mechanisms
of gamma oscillation generation are relatively well-articulated and may converge
across species, rendering gamma oscillation, and consequently the 40-Hz ASSR a
potentially promising target of translational research [88].
7.2.5 Mismatch Negativity
Mismatch negativity (MMN) is an automatically generated ERP component when a
sequence of relatively uniform stimuli is interrupted by the infrequent presentation
of deviant stimuli. Initially discovered in an auditory experimental procedure, MMN
is thought to reflect an automated detection of perceptual change or a sensory prerequisite of cognition and has been closely examined in relation to attentional processes
[94]. In particular, the MMN latency defines the response time change in the sensory
stimulus [131].
Although MMN can occur in any sensory system, it has been most frequently
studied in the visual and the auditory systems. In the case of auditory stimuli, MMN
occurs after an infrequent change in a repetitive sequence of sounds. The deviant
sound can differ from the standards in one or more perceptual features such as pitch,
duration, or loudness. In addition, MMN is usually evoked either by a change in
frequency, intensity, duration, and by apparent spatial locus of origin. Deficiency
in MMN appears to be an index of cognitive decline, irrespective of the specific