Response Properties of Single Neurons in the Zebra Finch Auditory Midbrain: Response Patterns, Frequency Coding, Intensity Coding, and Spike Latencies

2004 ◽  
Vol 91 (1) ◽  
pp. 136-151 ◽  
Author(s):  
Sarah M. N. Woolley ◽  
John H. Casseday
Keyword(s):  
Zebra Finch ◽  
Auditory Processing ◽  
Sound Level ◽  
Auditory Information ◽  
Response Patterns ◽  
Auditory Midbrain ◽  
Complex Signals ◽  
Tuning Curves ◽  
Intensity Coding ◽  
Frequency Coding

The avian mesencephalicus lateralis, dorsalis (MLd) is the auditory midbrain nucleus in which multiple parallel inputs from lower brain stem converge and through which most auditory information passes to reach the forebrain. Auditory processing in the MLd has not been investigated in songbirds. We studied the tuning properties of single MLd neurons in adult male zebra finches. Pure tones were used to examine tonotopy, temporal response patterns, frequency coding, intensity coding, spike latencies, and duration tuning. Most neurons had no spontaneous activity. The tonotopy of MLd is like that of other birds and mammals; characteristic frequencies (CFs) increase in a dorsal to ventral direction. Four major response patterns were found: 1) onset (49% of cells); 2) primary-like (20%); 3) sustained (19%); and 4) primary-like with notch (12%). CFs ranged between 0.9 and 6.1 kHz, matching the zebra finch hearing range and the power spectrum of song. Tuning curves were generally V-shaped, but complex curves, with multiple peaks or noncontiguous excitatory regions, were observed in 22% of cells. Rate-level functions indicated that 51% of nononset cells showed monotonic relationships between spike rate and sound level. Other cells showed low saturation or nonmonotonic responses. Spike latencies ranged from 4 to 40 ms, measured at CF. Spike latencies generally decreased with increasing sound pressure level (SPL), although paradoxical latency shifts were observed in 16% of units. For onset cells, changes in SPL produced smaller latency changes than for cells showing other response types. Results suggest that auditory midbrain neurons may be particularly suited for processing temporally complex signals with a high degree of precision.

Processing of Modulated Sounds in the Zebra Finch Auditory Midbrain: Responses to Noise, Frequency Sweeps, and Sinusoidal Amplitude Modulations

2005 ◽  
Vol 94 (2) ◽  
pp. 1143-1157 ◽  
Author(s):  
Sarah M. N. Woolley ◽  
John H. Casseday
Keyword(s):  
Zebra Finch ◽  
Auditory Processing ◽  
Frequency Tuning ◽  
Spike Rate ◽  
Auditory Midbrain ◽  
Complex Sounds ◽  
Tuning Curves ◽  
Wide Range ◽  
Band Limited ◽  
Frequency Sweeps

The avian auditory midbrain nucleus, the mesencephalicus lateralis, dorsalis (MLd), is the first auditory processing stage in which multiple parallel inputs converge, and it provides the input to the auditory thalamus. We studied the responses of single MLd neurons to four types of modulated sounds: 1) white noise; 2) band-limited noise; 3) frequency modulated (FM) sweeps, and 4) sinusoidally amplitude-modulated tones (SAM) in adult male zebra finches. Responses were compared with the responses of the same neurons to pure tones in terms of temporal response patterns, thresholds, characteristic frequencies, frequency tuning bandwidths, tuning sharpness, and spike rate/intensity relationships. Most neurons responded well to noise. More than one-half of the neurons responded selectively to particular portions of the noise, suggesting that, unlike forebrain neurons, many MLd neurons can encode specific acoustic components of highly modulated sounds such as noise. Selectivity for FM sweep direction was found in only 13% of cells that responded to sweeps. Those cells also showed asymmetric tuning curves, suggesting that asymmetric inhibition plays a role in FM directional selectivity. Responses to SAM showed that MLd neurons code temporal modulation rates using both spike rate and synchronization. Nearly all cells showed low-pass or band-pass filtering properties for SAM. Best modulation frequencies matched the temporal modulations in zebra finch song. Results suggest that auditory midbrain neurons are well suited for encoding a wide range of complex sounds with a high degree of temporal accuracy rather than selectively responding to only some sounds.

scholarly journals Intercollicular commissural connections refine the representation of sound frequency and level in the auditory midbrain

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Llwyd David Orton ◽  
Adrian Rees
Keyword(s):  
Auditory Processing ◽  
Sound Level ◽  
The Other ◽  
Auditory Midbrain ◽  
Auditory Pathways ◽  
Auditory Space ◽  
Signal Changes ◽  
Almost All ◽  
Inferior Colliculi ◽  
Commissural Connections

Connections unifying hemispheric sensory representations of vision and touch occur in cortex, but for hearing, commissural connections earlier in the pathway may be important. The brainstem auditory pathways course bilaterally to the inferior colliculi (ICs). Each IC represents one side of auditory space but they are interconnected by a commissure. By deactivating one IC in guinea pig with cooling or microdialysis of procaine, and recording neural activity to sound in the other, we found that commissural input influences fundamental aspects of auditory processing. The areas of nonV frequency response areas (FRAs) were modulated, but the areas of almost all V-shaped FRAs were not. The supra-threshold sensitivity of rate level functions decreased during deactivation and the ability to signal changes in sound level was decremented. This commissural enhancement suggests the ICs should be viewed as a single entity in which the representation of sound in each is governed by the other.

scholarly journals Auditory processing in the zebra finch midbrain: single unit responses and effect of rearing experience

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9363
Author(s):  
Priscilla Logerot ◽  
Paul F. Smith ◽  
Martin Wild ◽  
M. Fabiana Kubke
Keyword(s):  
Auditory System ◽  
Zebra Finch ◽  
Auditory Processing ◽  
A Priori ◽  
Auditory Brainstem ◽  
Zebra Finches ◽  
Auditory Midbrain ◽  
Virtual Absence ◽  
The Difference ◽  
Cross Fostering

In birds the auditory system plays a key role in providing the sensory input used to discriminate between conspecific and heterospecific vocal signals. In those species that are known to learn their vocalizations, for example, songbirds, it is generally considered that this ability arises and is manifest in the forebrain, although there is no a priori reason why brainstem components of the auditory system could not also play an important part. To test this assumption, we used groups of normal reared and cross-fostered zebra finches that had previously been shown in behavioural experiments to reduce their preference for conspecific songs subsequent to cross fostering experience with Bengalese finches, a related species with a distinctly different song. The question we asked, therefore, is whether this experiential change also changes the bias in favour of conspecific song displayed by auditory midbrain units of normally raised zebra finches. By recording the responses of single units in MLd to a variety of zebra finch and Bengalese finch songs in both normally reared and cross-fostered zebra finches, we provide a positive answer to this question. That is, the difference in response to conspecific and heterospecific songs seen in normal reared zebra finches is reduced following cross-fostering. In birds the virtual absence of mammalian-like cortical projections upon auditory brainstem nuclei argues against the interpretation that MLd units change, as observed in the present experiments, as a result of top-down influences on sensory processing. Instead, it appears that MLd units can be influenced significantly by sensory inputs arising directly from a change in auditory experience during development.

scholarly journals Mapping the contents of consciousness during musical imagery

2020 ◽  
Author(s):  
Mor Regev ◽  
Andrea R. Halpern ◽  
Adrian M. Owen ◽  
Aniruddh D Patel ◽  
Robert J Zatorre
Keyword(s):  
Auditory Processing ◽  
Conscious Experience ◽  
Auditory Information ◽  
Response Patterns ◽  
Dynamic Activity ◽  
Complex Sounds ◽  
Musical Imagery ◽  
Passive Listening ◽  
Neural Representations ◽  
Auditory Cortices

AbstractHumans can internally represent auditory information without an external stimulus. When imagining music, how similar are unfolding neural representations to those during the original perceived experience? Participants memorized six one-minute-long musical pieces with high accuracy. Functional MRI data were collected during: 1) silent imagery of melodies to the beat of a visual metronome; 2) same but while tapping to the beat; and 3) passive listening. During imagery, inter-subject comparison showed that melody-specific temporal response patterns were reinstated in right associative auditory cortices. When tapping accompanied imagery, the melody-specific neural patterns were extended to associative cortices bilaterally. These results indicate that the specific contents of conscious experience are encoded similarly during imagery and perception in the dynamic activity of auditory cortices. Furthermore, rhythmic motion can enhance the reinstatement of neural patterns associated with the experience of complex sounds, in keeping with models of motor to sensory influences in auditory processing.

Neuromodulatory Feedback to the Inferior Colliculus

2018 ◽  
pp. 576-610 ◽  
Author(s):  
Laura Hurley
Keyword(s):  
Inferior Colliculus ◽  
Auditory System ◽  
Auditory Processing ◽  
Internal State ◽  
Brain Regions ◽  
Auditory Information ◽  
Situational Variables ◽  
Acoustic Stimuli ◽  
Functionally Diverse ◽  
Behavioral Information

The inferior colliculus (IC) receives prominent projections from centralized neuromodulatory systems. These systems include extra-auditory clusters of cholinergic, dopaminergic, noradrenergic, and serotonergic neurons. Although these modulatory sites are not explicitly part of the auditory system, they receive projections from primary auditory regions and are responsive to acoustic stimuli. This bidirectional influence suggests the existence of auditory-modulatory feedback loops. A characteristic of neuromodulatory centers is that they integrate inputs from anatomically widespread and functionally diverse sets of brain regions. This connectivity gives neuromodulatory systems the potential to import information into the auditory system on situational variables that accompany acoustic stimuli, such as context, internal state, or experience. Once released, neuromodulators functionally reconfigure auditory circuitry through a variety of receptors expressed by auditory neurons. In addition to shaping ascending auditory information, neuromodulation within the IC influences behaviors that arise subcortically, such as prepulse inhibition of the startle response. Neuromodulatory systems therefore provide a route for integrative behavioral information to access auditory processing from its earliest levels.

Previously reward-associated sounds interfere with goal-directed auditory processing

2021 ◽  
pp. 174702182199003
Author(s):  
Andy J Kim ◽  
David S Lee ◽  
Brian A Anderson
Keyword(s):  
Visual Processing ◽  
Auditory Processing ◽  
Dichotic Listening ◽  
Auditory Information ◽  
Correct Identification ◽  
Subsequent Test ◽  
Dichotic Listening Task ◽  
Listening Task ◽  
Task Irrelevant ◽  
Visual Domain

Previously reward-associated stimuli have consistently been shown to involuntarily capture attention in the visual domain. Although previously reward-associated but currently task-irrelevant sounds have also been shown to interfere with visual processing, it remains unclear whether such stimuli can interfere with the processing of task-relevant auditory information. To address this question, we modified a dichotic listening task to measure interference from task-irrelevant but previously reward-associated sounds. In a training phase, participants were simultaneously presented with a spoken letter and number in different auditory streams and learned to associate the correct identification of each of three letters with high, low, and no monetary reward, respectively. In a subsequent test phase, participants were again presented with the same auditory stimuli but were instead instructed to report the number while ignoring spoken letters. In both the training and test phases, response time measures demonstrated that attention was biased in favour of the auditory stimulus associated with high value. Our findings demonstrate that attention can be biased towards learned reward cues in the auditory domain, interfering with goal-directed auditory processing.

scholarly journals Event related potentials in cases of amblyaudia

2020 ◽  
Vol 6 (4) ◽  
pp. 747
Author(s):  
Wessam Mostafa Essawy
Keyword(s):  
Auditory Processing ◽  
Event Related Potentials ◽  
Speech Development ◽  
Screening Tests ◽  
Control Group ◽  
Auditory Information ◽  
Central Auditory Processing ◽  
Auditory Processing Disorders ◽  
Central Auditory Processing Disorders ◽  
Related Potentials

<p class="abstract"><strong>Background:</strong> Amblyaudia is a weakness in the listener’s binaural processing of auditory information. Subjects with amblyaudia also demonstrate binaural integration deficits and may display similar patterns in their evoked responses in terms of latency and amplitude of these responses. The purpose of this study was to identify the presence of amblyaudia in a population of young children subjects and to measure mismatch negativity (MMN), P300 and cortical auditory evoked potentials (CAEPs) for those individuals.</p><p class="abstract"><strong>Methods:</strong> Subjects included in this study were divided into 2 groups control group that consisted of 20 normal hearing subjects with normal developmental milestones and normal speech development. The study group (GII) consisted of 50 subjects with central auditory processing disorders (CAPDs) diagnosed by central auditory screening tests. </p><p class="abstract"><strong>Results:</strong> With using dichotic tests including dichotic digits test (DDT) and competing sentence test (CST), we could classify these cases into normal, dichotic dysaudia, amblyaudia, and amblyaudia plus with percentages (40%, 14%, 38%, 8% respectively). Using event related potentials, we found that P300 and MMN are more specific in detecting neurocognitive dysfunction related to allocation of attentional resources and immediate memory in these cases.</p><p class="abstract"><strong>Conclusions:</strong> The presence of amblyaudia in cases of central auditory processing disorders (CAPDs) and event related potentials is an objective tool for diagnosis, prognosis and follow up after rehabilitation.</p>

Auditory-vocal cholinergic pathway in the songbird brain

2000 ◽  
Vol 78 (12) ◽  
pp. 1072-1076 ◽  
Author(s):  
Rui Li ◽  
Ikuo Taniguchi ◽  
Hironobu Sakaguchi
Keyword(s):  
Zebra Finch ◽  
Basal Forebrain ◽  
Cholinergic Neurons ◽  
Auditory Pathway ◽  
Song Learning ◽  
Cholinergic Innervation ◽  
Auditory Information ◽  
Cholinergic Pathway ◽  
Song Control Nuclei ◽  
Song Control

Male zebra finches learn to imitate a tutor's song through auditory and motor learning. The two main song control nuclei in the zebra finch forebrain, the higher vocal center (HVC) and the robust nucleus of the archistriatum (RA), receive cholinergic innervation from the ventral paleostriatum (VP) of the basal forebrain which may play a key role in song learning. By injecting neuroanatomical tracers, we found a topographically segregated pathway from nucleus ovoidalis (Ov) to VP that in turn projects in a topographic fashion to HVC and RA. Ov is a major relay in the main ascending auditory pathway. The results suggest that the cholinergic neurons in the VP responsible for song learning are regulated by auditory information from the Ov.Key words: auditory pathway, cholinergic pathway, song control nucleus, zebra finch.

scholarly journals Specific loss of neural sensitivity to interaural time difference of unmodulated noise stimuli following noise-induced hearing loss

2020 ◽  
Vol 124 (4) ◽  
pp. 1165-1182
Author(s):  
Hariprakash Haragopal ◽  
Ryan Dorkoski ◽  
Austin R. Pollard ◽  
Gareth A. Whaley ◽  
Timothy R. Wohl ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Interaural Time Difference ◽  
Acoustic Trauma ◽  
Sound Level ◽  
Broadband Noise ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Midbrain Neurons ◽  
Perceptual Abilities ◽  
Encode Time

Sensorineural hearing loss compromises perceptual abilities that arise from hearing with two ears, yet its effects on binaural aspects of neural responses are largely unknown. We found that, following severe hearing loss because of acoustic trauma, auditory midbrain neurons specifically lost the ability to encode time differences between the arrival of a broadband noise stimulus to the two ears, whereas the encoding of sound level differences between the two ears remained uncompromised.

scholarly journals Different Serotonin Receptor Agonists Have Distinct Effects on Sound-Evoked Responses in Inferior Colliculus

2006 ◽  
Vol 96 (5) ◽  
pp. 2177-2188 ◽  
Author(s):  
Laura M. Hurley
Keyword(s):  
Inferior Colliculus ◽  
Auditory Processing ◽  
Serotonin Receptors ◽  
Serotonin Receptor ◽  
Frequency Tuning ◽  
Receptor Subtypes ◽  
Tuning Curves ◽  
Wide Range ◽  
Selective Agonists ◽  
Auditory Nucleus

The neuromodulator serotonin has a complex set of effects on the auditory responses of neurons within the inferior colliculus (IC), a midbrain auditory nucleus that integrates a wide range of inputs from auditory and nonauditory sources. To determine whether activation of different types of serotonin receptors is a source of the variability in serotonergic effects, four selective agonists of serotonin receptors in the serotonin (5-HT) 1 and 5-HT2 families were iontophoretically applied to IC neurons, which were monitored for changes in their responses to auditory stimuli. Different agonists had different effects on neural responses. The 5-HT1A agonist had mixed facilitatory and depressive effects, whereas 5-HT1B and 5-HT2C agonists were both largely facilitatory. Different agonists changed threshold and frequency tuning in ways that reflected their effects on spike count. When pairs of agonists were applied sequentially to the same neurons, selective agonists sometimes affected neurons in ways that were similar to serotonin, but not to other selective agonists tested. Different agonists also differentially affected groups of neurons classified by the shapes of their frequency-tuning curves, with serotonin and the 5-HT1 receptors affecting proportionally more non-V-type neurons relative to the other agonists tested. In all, evidence suggests that the diversity of serotonin receptor subtypes in the IC is likely to account for at least some of the variability of the effects of serotonin and that receptor subtypes fulfill specialized roles in auditory processing.

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