Auditory evoked field
Encyclopedia
Auditory evoked field or AEF is an induced neural activity (by an auditory stimulus) that is recorded via magnetoencephalography (MEG), which is an equivalent of Auditory evoked potential (AEP) recorded by electroencephalography
. The advantage of AEF over AEP is the powerful spatial resolution provided by magnetic field
recording, which AEP lacks. Thus, researchers using AEF often deals with the global responses of the whole brain at the cortical
level while focusing on the role of the auditory pathway. The common applications of AEF are prenatal and neonatal hearing screening, cortical pitch
perception, language comprehension, and attention.
At 100 ms after stimulus onset occurs the most prominent response in the late latency range, the M100, which corresponds to the N1
peak of the auditory long latency response potential, or ALR. M100 is the most widely used magnetic field response clinically. In 2007, Lütkenhöner et al. demonstrated that M100 can be applied to estimate hearing threshold to a higher degree of accuracy.
Longer latency responses after 100 ms are referred as event-related field
or ERF that includes M150, M200, M300 (equivalent of P300
), and M400.
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
. The advantage of AEF over AEP is the powerful spatial resolution provided by magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
recording, which AEP lacks. Thus, researchers using AEF often deals with the global responses of the whole brain at the cortical
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
level while focusing on the role of the auditory pathway. The common applications of AEF are prenatal and neonatal hearing screening, cortical 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,...
perception, language comprehension, and attention.
Sources and types of responses
The main source of the auditory evoked field is the auditory cortex and the association cortices. The earliest cortical components of AEF is equivalent to the middle latency response or MLR of the EEG evoked potential, called the middle latency auditory evoked field or MLAEF, which occurs at 30 to 50 ms after the stimulus onset. M30 and M50, occurring at 30 and 50 ms after the stimulus onset, correspond to the Pa and Pb peaks of MLR. The M50 response was often used to study the correlation of aging and hearing loss. Research has shown that the amplitude of contralateral M50 enlarges with age.At 100 ms after stimulus onset occurs the most prominent response in the late latency range, the M100, which corresponds to the N1
N100
The N100 smartphone is the first mobile phone to have an integrated 10 megapixel CMOS sensor, TV tuner and a camcorder that shoots up to 30 frames per second DVD quality....
peak of the auditory long latency response potential, or ALR. M100 is the most widely used magnetic field response clinically. In 2007, Lütkenhöner et al. demonstrated that M100 can be applied to estimate hearing threshold to a higher degree of accuracy.
Longer latency responses after 100 ms are referred as event-related field
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....
or ERF that includes M150, M200, M300 (equivalent of P300
P300
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...
), and M400.
See also
- Evoked activityEvoked activityEvoked activity is brain activity that is the result of a task, sensory input or motor output. It is opposed to spontaneous brain activity during the absence of any explicit task....
- Evoked fieldEvoked fieldEvoked fields are part of the magnetoencephalogram. They are brain signals evoked by sensory stimulation, but usually buried by the ongoing brain activity...
- MagnetoencephalographyMagnetoencephalographyMagnetoencephalography is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using arrays of SQUIDs...
- Auditory evoked potential