Sensitivity of neurons in cat primary auditory cortex to tones and frequency-modulated stimuli. I: Effects of variation of stimulus parameters. Heil, P, Rajan, R, & Irvine, D. Hear Res, 63(1-2):108-34, 1992.
abstract   bibtex   
In the primary auditory cortex (AI) of barbiturate-anesthetized cats multi-unit responses to tones and to frequency-modulated (FM) tonal stimuli were analyzed. Characteristic frequency (CF), sharpness of tuning, minimum threshold, and dynamic range of spike count–intensity functions were determined. Minimum threshold and dynamic range were positively correlated. The response functions to unidirectional FM sweeps of varying linear rate of change of frequency (RCF) that traversed the excitatory frequency response areas (FRAs) displayed a variety of shapes. Preferences for fast RCFs (> 1000 kHz/s) were most common. Best RCF was not correlated with measures of sharpness of tuning. Directional preference and sensitivity were quantified by a DS index which varied with RCF. About two-thirds of the multi-unit responses showed a preference for downward sweeps. Directional sensitivity was independent of CF and independent of best RCF. Measurements of latencies of phasic responses to unidirectional FM sweeps of different RCF demonstrated that the discharges of a given multi-unit over its effective RCF range were initiated at the same instantaneous frequency (effective Fi), independent of RCF. Effective Fis fell within the excitatory FRA of a given multi-unit. The relationships of effective Fis to CF show that responses were evoked only when the frequency of the signal was modulated towards CF and not when modulated away from it, and that responses were initiated before the modulation reached CF. Changes in the range and depth of modulation had only minor, if any, effects on RCF response characteristics, FM directional sensitivity, and effective Fis, as long as the beginning and ending frequencies of FM sweeps fell outside a multi-unit's FRA. Stimulus intensity also had only moderate effects on RCF response characteristics and DS. However, effective Fis were influenced in systematic fashions; with increases in intensity, effective Fis to upward and downward sweeps decreased and increased, respectively. Thus, for higher intensities FM responses were initiated at instantaneous frequencies occurring earlier in the signal. The results are compared with previous data on tone and FM sensitivity of auditory neurons in cortical and subcortical structures, and mechanisms of FM rate and directional sensitivity are discussed. The topographic representations of these neuronal properties in AI are reported in the companion report.
@Article{Heil1992,
  author   = {P Heil and R Rajan and DR Irvine},
  journal  = {Hear Res},
  title    = {Sensitivity of neurons in cat primary auditory cortex to tones and frequency-modulated stimuli. {I}: {E}ffects of variation of stimulus parameters.},
  year     = {1992},
  number   = {1-2},
  pages    = {108-34},
  volume   = {63},
  abstract = {In the primary auditory cortex (AI) of barbiturate-anesthetized cats
	multi-unit responses to tones and to frequency-modulated (FM) tonal
	stimuli were analyzed. Characteristic frequency (CF), sharpness of
	tuning, minimum threshold, and dynamic range of spike count--intensity
	functions were determined. Minimum threshold and dynamic range were
	positively correlated. The response functions to unidirectional FM
	sweeps of varying linear rate of change of frequency (RCF) that traversed
	the excitatory frequency response areas (FRAs) displayed a variety
	of shapes. Preferences for fast RCFs (> 1000 kHz/s) were most common.
	Best RCF was not correlated with measures of sharpness of tuning.
	Directional preference and sensitivity were quantified by a DS index
	which varied with RCF. About two-thirds of the multi-unit responses
	showed a preference for downward sweeps. Directional sensitivity
	was independent of CF and independent of best RCF. Measurements of
	latencies of phasic responses to unidirectional FM sweeps of different
	RCF demonstrated that the discharges of a given multi-unit over its
	effective RCF range were initiated at the same instantaneous frequency
	(effective Fi), independent of RCF. Effective Fis fell within the
	excitatory FRA of a given multi-unit. The relationships of effective
	Fis to CF show that responses were evoked only when the frequency
	of the signal was modulated towards CF and not when modulated away
	from it, and that responses were initiated before the modulation
	reached CF. Changes in the range and depth of modulation had only
	minor, if any, effects on RCF response characteristics, FM directional
	sensitivity, and effective Fis, as long as the beginning and ending
	frequencies of FM sweeps fell outside a multi-unit's FRA. Stimulus
	intensity also had only moderate effects on RCF response characteristics
	and DS. However, effective Fis were influenced in systematic fashions;
	with increases in intensity, effective Fis to upward and downward
	sweeps decreased and increased, respectively. Thus, for higher intensities
	FM responses were initiated at instantaneous frequencies occurring
	earlier in the signal. The results are compared with previous data
	on tone and FM sensitivity of auditory neurons in cortical and subcortical
	structures, and mechanisms of FM rate and directional sensitivity
	are discussed. The topographic representations of these neuronal
	properties in AI are reported in the companion report.},
  keywords = {Computing Methodologies, Human, Language, Learning, Mental Processes, Models, Theoretical, Stochastic Processes, Support, U.S. Gov't, Non-P.H.S., Cognition, Linguistics, Neural Networks (Computer), Practice (Psychology), Non-U.S. Gov't, Memory, Psychological, Task Performance and Analysis, Time Factors, Visual Perception, Adult, Attention, Discrimination Learning, Female, Male, Short-Term, Mental Recall, Orientation, Pattern Recognition, Visual, Perceptual Masking, Reading, Concept Formation, Form Perception, Animals, Corpus Striatum, Shrews, P.H.S., Visual Cortex, Visual Pathways, Acoustic Stimulation, Auditory Cortex, Auditory Perception, Cochlea, Ear, Gerbillinae, Glycine, Hearing, Neurons, Space Perception, Strychnine, Adolescent, Decision Making, Reaction Time, Astrocytoma, Brain Mapping, Brain Neoplasms, Cerebral Cortex, Electric Stimulation, Electrophysiology, Epilepsy, Temporal Lobe, Evoked Potentials, Frontal Lobe, Noise, Parietal Lobe, Scalp, Child, Language Development, Psycholinguistics, Brain, Perception, Speech, Vocalization, Animal, Discrimination (Psychology), Hippocampus, Rats, Calcium, Chelating Agents, Excitatory Postsynaptic Potentials, Glutamic Acid, Guanosine Diphosphate, In Vitro, Neuronal Plasticity, Pyramidal Cells, Receptors, AMPA, Metabotropic Glutamate, N-Methyl-D-Aspartate, Somatosensory Cortex, Synapses, Synaptic Transmission, Thionucleotides, Action Potentials, Calcium Channels, L-Type, Electric Conductivity, Entorhinal Cortex, Neurological, Long-Evans, Infant, Mathematics, Statistics, Probability Learning, Problem Solving, Psychophysics, Association Learning, Child Psychology, Habituation (Psychophysiology), Probability Theory, Analysis of Variance, Semantics, Symbolism, Behavior, Eye Movements, Macaca mulatta, Prefrontal Cortex, Cats, Dogs, Haplorhini, Photic Stimulation, Electroencephalography, Nervous System Physiology, Darkness, Grasshoppers, Light, Membrane Potentials, Neural Inhibition, Afferent, Picrotoxin, Vision, Deoxyglucose, Injections, Microspheres, Neural Pathways, Rhodamines, Choice Behavior, Speech Perception, Verbal Learning, Dominance, Cerebral, Fixation, Ocular, Language Tests, Random Allocation, Comparative Study, Saguinus, Sound Spectrography, Species Specificity, Audiometry, Auditory Threshold, Calibration, Data Interpretation, Statistical, 1464565},
}

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