Abstract
A basic feature of communication signals is a dynamic change in frequency. One stimulus that lends itself well to investigating the frequency changes contained in these signals is the frequency modulated (FM) sweep. While many studies have investigated FM sweep responses in the auditory midbrain and cortex, relatively few have examined them in the thalamus. To this end, we investigated the responses of single units in the ventral division of the medial geniculate nucleus (MGNv) of the rat to FM sweeps. Both upward- (changing from low to high frequency) and downward-directed (changing from high to low frequency) FM sweeps were presented at four rates of frequency modulation (i.e., speed). Results showed that the majority (76%) of the cells preferred fast or medium FM sweeps. For direction selectivity, just under half of the units (47%) exhibited a preference for the direction of FM sweep. The results suggest that there is a greater degree of direction but not speed selectivity at progressively higher levels in the auditory pathway.
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References
Aitkin L (1985) The auditory midbrain: structure and function in the central auditory pathway. Humana, Clifton, NJ
Aitkin LM, Webster WR (1972) Medial geniculate body of the cat: organization and responses to tonal stimuli of neurons in ventral division. J Neurophysiol 35:365–380
Creutzfeldt O, Hellweg F-C, Schreiner C (1980) Thalamocortical transformation of responses to complex auditory stimuli. Exp Brain Res 39:87–104
Felsheim C, Ostwald J (1996) Responses to exponential frequency modulations in the rat inferior colliculus. Hear Res 98:137–151
Gaese BH, Ostwald J (1995) Temporal coding of amplitude and frequency in the rat auditory cortex. Eur J Neurosci 7:438–450
Heil P, Rajan R, Irvine DRF (1992) Sensitivity of neurons in the cat primary auditory cortex to tones and frequency-modulated stimuli. I: Effects of variation of stimulus parameters. Hear Res 63:108–134
Imig TJ, Morel A (1985) Tonotopic organization in ventral nucleus of medial geniculate body in the cat .J Neurophysiol 53:309–340
Kaltwasser MT (1990) Acoustic signalling in the black rat (Rattus rattus). J Comp Psychol 104:227–232
Lee HJ, Wallani T, Mendelson JR (2002) Effects of aging on temporal processing speed in the inferior colliculus. Hear Res (in press)
Liano DA, Feng AS (1999) Response characteristics of neurons in the medial geniculate body of the little brown bat to simple and temporally-patterned sounds. J Comp Physiol [A] 184:371–385
Mendelson JR, Cynader MS (1985) Sensitivity of the cat primary auditory cortex (AI) neurons to the direction and rate of frequency modulations. Brain Res 327:331–335
Mendelson JR, Grasse KL (1992) A comparison of monaural and binaural responses to frequency modulation (FM) sweeps in the cat primary auditory cortex. Exp Brain Res 91:435–454
Mendelson JR, Ricketts C (2001) Age-related temporal processing speed deterioration in auditory cortex. Hear Res 158:84–94
Mendelson JR, Schreiner CE, Grasse KL, Sutter M (1993) Functional topography of cat primary auditory cortex: responses to frequency-modulated sweeps. Exp Brain Res 94:65–87
Miller LM, Escabai MA, Read HL, Schreiner CE (2002) Spectrotemporal receptive fields in the lemniscal auditory thalamus and cortex. J Neurophys 87:516–527
O'Neill WE, Brimijoin WO (2002) Directional selectivity for FM sweeps in the suprageniculate nucleus of the mustached bat medial geniculate body. J Neurophys 88:172–187
Nelkin I, Versnel H (2000) Responses to linear and logarithmic frequency-modulated sweeps in ferret primary auditory cortex. Eur J Neurosci 12:549–562
Paxinos G, Watson C (1986) The rat brain in stereotaxic coordinates, 2nd edn. Academic, Sydney
Pick GF (1979) A study of frequency transition in cat vocalization. J Acoust Soc Am 66:594–597
Poon PWF, Chen X, Hwang JC (1991) Basic determinants for FM responses in the inferior colliculus of rats. Exp Brain Res 83:598–606
Poon PWF, Chen X, Cheung YM (1992) Differences in FM response correlate with morphology of neurons in the rat inferior colliculus. Exp Brain Res 91:94–104
Rees A, Moller AR (1983) Responses of neurons in the inferior colliculus of the rat to AM and FM tones. Hear Res 10:301–330
Ricketts C, Mendelson JR, Anand B, English R (1998) Responses to time-varying stimuli in rat auditory cortex. Hear Res 123:27–30
Shamma SA, Fleshman JW, Wiser PW, Hersnel H (1993) Organization of response areas in the ferret primary auditory cortex. J Neurophysiol 69:367–383
Shore SE, Nuttall AL (1985) High-synchrony cochlear compound action potentials evoked by rising frequency-swept tone bursts. J Acoust Soc Am 78:1286–1295
Suga N (1965) Analysis of frequency modulated sounds by auditory neurons of echolocating bats. J Physiol 179:26–53
Tian B, Rauschecker JP (1994) Processing of frequency-modulated sounds in the cat's anterior auditory field. J Neurophysiol 71:1959–1975
Vartanian IA (1974) On mechanisms of specialized reactions of central auditory neurons to frequency modulated sounds. Acustica 31:305–310
Wenstrupp JJ (1999) Frequency organization and responses to complex sounds in the medial geniculate body of the mustached bat. J Neurophysiol 82:2528–2544
Winer JA (1985) The medial geniculate body of the cat. Adv Anat Embryol Cell Biol 86:1–98
Zhang Y, Suga N (2000) Modulation of responses and frequency tuning of thalamic and collicular neurons by cortical activation in mustached bats. J Neurophysiol 84:325–333
Acknowledgements
This research was supported by NSERC grant WFA0123096. We thank Ralph English for his help in this study.
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Lui, B., Mendelson, J.R. Frequency modulated sweep responses in the medial geniculate nucleus. Exp Brain Res 153, 550–553 (2003). https://doi.org/10.1007/s00221-003-1618-y
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DOI: https://doi.org/10.1007/s00221-003-1618-y