Combination-sensitive neurons in the inferior colliculus.
Acoustic Stimulation; Animals; Auditory Cortex/metabolism; Chiroptera; Doppler; Inferior Colliculi/*cytology/metabolism; Neurons/cytology/*physiology; Sound Localization; Transcranial; Ultrasonography
We examined whether neurons in the inferior colliculus of the mustached bat (Pteronotus parnellii) are combination sensitive, responding to both low- and high-frequency components of the bat's sonar signal. These neurons, previously reported in the thalamus and cortex, analyze sonar target features including distance. Of 82 single units and 36 multiple units from the 58-112 kHz representations of the inferior colliculus, most (86%) displayed sensitivity to low-frequency sounds that was tuned in the range of the fundamental biosonar component (24-31 kHz). All histologically localized units were in the central nucleus of the inferior colliculus (ICC). There were two major types of combination-sensitive influences. Many neurons were facilitated by low-frequency sounds and selective for particular delays between the low- and high-frequency components. In other neurons, the low-frequency signal was inhibitory if presented simultaneously or a few milliseconds prior to the high-frequency signal. The results indicate that mechanisms creating specialized frequency comparisons and delay sensitivity in combination-sensitive neurons operate at the ICC or below. Since combination sensitivity or multipeaked tuning curves occur in the auditory systems of many species, ICC neurons in these animals may also respond to species-specific frequency combinations.
Mittmann D H; Wenstrup J J
Hearing research
1995
1995-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0378-5955(95)00164-x" target="_blank" rel="noreferrer noopener">10.1016/0378-5955(95)00164-x</a>
Early development of intrinsic and synaptic properties of chicken nucleus laminaris neurons.
Action Potentials/physiology; Aging/physiology; Animals; Auditory Pathways/cytology/*embryology/physiology; Auditory Perception/physiology; Body Patterning/physiology; Brain Stem/cytology/*embryology/physiology; Cell Differentiation/*physiology; Chick Embryo; Chickens; Cochlear Nucleus/cytology/*embryology/physiology; Excitatory Postsynaptic Potentials/physiology; Neurons/cytology/*physiology; Patch-Clamp Techniques; Potassium Channels; Sound Localization/physiology; Synapses/*physiology/ultrastructure; Time Factors; Voltage-Gated/physiology
Onset of auditory brainstem responses in chickens takes place at about embryonic day 11/12 (E11/12). We investigated early development of neuronal properties of chicken nucleus laminaris neurons, the third-order auditory neurons critically involved in sound localization. Whole-cell patch recordings were performed in brainstem slices obtained at E10, E11, E12, E14, E16, and E18. At E18 neurons acquired an adult-like firing pattern in response to prolonged depolarizing current injections, with a single spike at the onset of the current injection followed by a plateau of membrane potential. At earlier ages, however, multiple spikes and/or subthreshold membrane potential oscillations were generated. We observed a \textgreaterthreefold reduction in input resistance from E10 to E18, and progressive changes in excitability properties, such as elevated threshold currents for spike generation, increased spike rising and falling rates, accompanied by reduced spike width and enhanced ability to follow high frequency inputs. Consistent with development of firing properties, the amplitude of voltage-gated potassium channel (Kv) currents increased by approximately threefold from E10 to E18, with a dramatic increase ( approximately ninefold) in the low threshold component. Excitatory postsynaptic potentials (EPSPs) were first recorded at E10, prior to and independent of the cochlear afferent inputs from the auditory nerve to the cochlear nucleus. EPSPs became markedly briefer in duration during the period studied. We conclude that the basic features of the key neuronal properties of NL neurons are well constructed during early development from E10 to E18.
Gao H; Lu Y
Neuroscience
2008
2008-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neuroscience.2008.01.059" target="_blank" rel="noreferrer noopener">10.1016/j.neuroscience.2008.01.059</a>