Summary
We have studied the effects of masking sounds on auditory evoked magnetic fields (AEFs) of healthy humans. The AEFs were elicited by 25-ms tones presented randomly to the left or to the right ear, and the responses were recorded over the right auditory cortex. Without masking, the 100-ms deflection (N100m) was of somewhat higher amplitude and of shorter latency for contrathan ipsilateral stimuli. Continuous speech, music, or intermittent noise, delivered to the left ear, dampened N100m to stimulation of both ears without correlated changes in sensation. Intermittent noise had a weaker effect on N100m than speech or music. Continuous noise fed to the left ear dampened both the sensation of and the responses to the left-ear stimuli, with no significant effect on the responses to the right-ear stimuli. The results suggest that the masking effects of continuous noise, seen at the auditory cortex, derive mainly from the periphery whereas the effects of sounds with intensity and frequency modulations take place at more central auditory pathways.
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References
Brugge J, Reale R (1985) Auditory cortex. In: Peters A, Jones E (eds) Cerebral cortex, Vol 4. Association and auditory cortices. Plenum Press, New York, pp 229–271
Elberling C, Bak C, Kofoed B, Lebech J, Saermark K (1980) Magnetic auditory responses from the human brain. A preliminary report. Scand Audiol 9: 185–190
Elberling C, Bak C, Kofoed B, Lebech J, Saermark K (1981) Auditory magnetic fields from the human cortex. Influence of stimulus intensity. Scand Audiol 10: 203–207
Elberling C, Bak C, Kofoed B, Lebech J, Saermark K (1982) Auditory magnetic fields from the human cerebral cortex: location and strength of an equivalent current dipole. Acta Neurol Scand 65: 553–569
Hari R, Ilmoniemi R (1986) Cerebral magnetic fields. CRC Crit Rev Biomed Engin 14: 93–126
Hari R, Mäkelä J (1987) Neuromagnetic studies of the human auditory cortex. In: Barber C, Blum T (eds) Evoked potentials III. Butterworths, Boston London, pp 130–135
Hari R, Aittoniemi K, Järvinen M-L, Katila T, Varpula T (1980) Auditory evoked transient and sustained magnetic fields of the human brain. Localization of neural generators. Exp Brain Res 40: 237–240
Hari R, Kaila K, Katila T, Tuomisto T, Varpula T (1982) Interstimulus-interval dependence of the auditory vertex response and its magnetic counterpart: implications for their neural generation. Electroenceph Clin Neurophysiol 54: 561–569
Hari R, Joutsiniemi SL, Sarvas J (1987a) Spatial resolution of neuromagnetic recordings: theoretical calculations in a spherical model. Electroenceph Clin Neurophysiol 26: 31–43
Hari R, Pelizzone M, Mäkelä JP, Hällström J, Leinonen L, Lounasmaa OV (1987b) Neuromagnetic responses of the human auditory cortex to on and offsets of noise bursts. Audiology 25: 31–43
Hawkins HL, Presson J (1986) Auditory information processing. In: Boff KR, Kaufman L, Thomas JP (eds) Handbook of perception and human performance. John Wiley and Sons, New York, Chap 26, pp 1–64
Knuutila J, Ahlfors S, Ahonen A, Hällström J, Kajola M, Lounasmaa OV (1987) A large-area low-noise seven-channel DC SQUID magnetometer for brain research. Rev Sci Instrum 58: 2145–2156
Mäkelä J, Hari R, Leinonen L (1987a) Magnetic responses of the human auditory cortex to noise/tone-transitions. Electroenceph Clin Neurophysiol (in press)
Mäkelä JP, Hari R, Linnankivi A (1987b) Different analysis of frequency and amplitude modulations of a continuous tone in the human auditory cortex: a neuromagnetic study. Hearing Res 27: 257–264
Näätänen R, Picton T (1987) The N1 wave of the human electric and magnetic response to sound: a review and analysis of the component structure. Psychophysiol 24: 375–425
Pantev C, Lütkenhöner B, Hoke M, Lehnertz K (1986) Comparison between simultaneously measured auditory-evoked magnetic fields and potentials elicited by ipsilateral, contralateral and binaural tone burst stimulation. Audiology 25: 54–61
Pelizzone M, Hari R, Mäkelä JP, Huttunen J, Ahlfors S, Hämälänen M (1987) Cortical origin of middle-latency auditory evoked responses in man. Neurosci Lett 82: 303–307
Phillips DP (1985) Temporal response features of cat auditory cortex neurons contributing to sensitivity to tones delivered in the presence of continuous tone. Hearing Res 19: 253–268
Phillips DP, Cynader MS (1985) Some neural mechanisms in the cat's auditory cortex underlying sensitivity to combined tone and wide-spectrum noise stimuli. Hearing Res 18: 87–102
Romani GL, Williamson SJ, Kaufman L (1982) Tonotopic organization of the human auditory cortex. Science 216: 1339–1340
Shamma SA, Symmes D (1985) Patterns of inhibition in auditory cortical cells in awake squirrel monkeys. Hearing Res 19:1–13
Woods DL, Hillyard SA, Hansen JC (1984) Event-related brain potentials reveal similar attentional mechanisms during selective listening and shadowing. J Exp Psychol 10: 761–777
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Hari, R., Mäkelä, J.P. Modification of neuromagnetic responses of the human auditory cortex by masking sounds. Exp Brain Res 71, 87–92 (1988). https://doi.org/10.1007/BF00247524
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DOI: https://doi.org/10.1007/BF00247524