Duration Selective Neurons in the Inferior Colliculus of the Rat: Topographic Distribution and Relation of Duration Sensitivity to Other Response Properties.
From: Auditory Neurophysiology Unit, Laboratory for the Neurobiology of Hearing, The Institute of Neuroscience of Castilla y León and Faculty of Medicine, University of Salamanca, Salamanca, Spain.
Journal of neurophysiology
- Publish Date: Feb 2006
- ISSN: 0022-3077
- Volume: 95
- Issue: 2
- Pages: 823-36
- Medium: Print
- Language: English
- Citation (JAMA): Pérez-González D, Malmierca M S, Moore J M, et al. Duration Selective Neurons in the Inferior Colliculus of the Rat: Topographic Distribution and Relation of Duration Sensitivity to Other Response Properties.. J. Neurophysiol. Feb 2006;95:823-36
Abstract
Many animals use duration to help them identify the source and meaning of a sound. Duration-sensitive neurons have been found in the auditory midbrain of mammals and amphibians, where their selectivity seems to correspond to the lengths of species-specific vocalizations. In this study, single neurons in the rat inferior colliculus (IC) were tested for sensitivity to sound duration. About one-half (54%) of the units sampled showed some form of duration selectivity. The majority of these (76%) were long-pass neurons that responded to sounds exceeding some duration threshold (range: 5-60 ms). Band-pass neurons, which only responded to a restricted range of durations, made up 13% of duration-sensitive neurons (best durations: 15-120 ms). Other units displayed short-pass (2%) or mixed (9%) response patterns. The majority of duration-sensitive neurons were localized outside the central nucleus of the IC, especially in the dorsal cortex, where more than one-half of the neurons sampled had long-pass selectivity for duration. Band-pass duration tuned neurons were only found outside the central nucleus. Characteristics of duration-sensitive neurons in the rat support the idea that this filtering arises through an interaction of excitatory and inhibitory inputs that converge in the IC. Band-pass neurons typically responded at sound offset, suggesting that their tuning is created through the same mechanisms that have been described in echolocating bats. The finding that the first-spike latencies of all long-pass neurons were longer than the shortest duration to which they responded supports the idea that they receive transient inhibition before, or simultaneously with, a sustained excitatory input. The ranges of selectivity in rat IC neurons are within the range of durations of rat vocalizations. These data suggest that a population of neurons in the rat IC have evolved to transmit information about behaviorally relevant sound durations using mechanisms that are common to all mammals, with an emphasis on long-pass tuning characteristics.
Mesh Headings (Keywords): Acoustic Stimulation, Action Potentials, Animals, Auditory Pathways, Auditory Perception, Auditory Threshold, Differential Threshold, Inferior Colliculi, Male, Neurons, Rats, Rats, Long-Evans, Rats, Wistar, Reaction Time, Sensitivity and Specificity, Sound Localization, Time Factors
Check for Full Text / PubMed Unique Identifier (PMID): 16192332
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