scholarly journals Long-Lasting Context Dependence Constrains Neural Encoding Models in Rodent Auditory Cortex

2009 ◽  
Vol 102 (5) ◽  
pp. 2638-2656 ◽  
Author(s):  
Hiroki Asari ◽  
Anthony M. Zador
Keyword(s):  
Auditory Cortex ◽  
Auditory Processing ◽  
Cortical Neurons ◽  
Stream Segregation ◽  
Context Dependence ◽  
Neural Encoding ◽  
Response Component ◽  
Presynaptic Mechanisms ◽  
Acoustic Processing

Acoustic processing requires integration over time. We have used in vivo intracellular recording to measure neuronal integration times in anesthetized rats. Using natural sounds and other stimuli, we found that synaptic inputs to auditory cortical neurons showed a rather long context dependence, up to ≥4 s (τ ∼ 1 s), even though sound-evoked excitatory and inhibitory conductances per se rarely lasted ≳100 ms. Thalamic neurons showed only a much faster form of adaptation with a decay constant τ <100 ms, indicating that the long-lasting form originated from presynaptic mechanisms in the cortex, such as synaptic depression. Restricting knowledge of the stimulus history to only a few hundred milliseconds reduced the predictable response component to about half that of the optimal infinite-history model. Our results demonstrate the importance of long-range temporal effects in auditory cortex and suggest a potential neural substrate for auditory processing that requires integration over timescales of seconds or longer, such as stream segregation.

scholarly journals Modulation of auditory responses by visual inputs in the mouse auditory cortex

2021 ◽  
Author(s):  
Sudha Sharma ◽  
Hemant Kumar Srivastava ◽  
Sharba Bandyopadhyay
Keyword(s):  
Auditory Cortex ◽  
Auditory Processing ◽  
Cortical Neurons ◽  
Visual Information ◽  
Visual Stimulation ◽  
Inhibitory Neurons ◽  
Visual Responses ◽  
Full Field ◽  
Auditory Responses ◽  
Layer 2

AbstractSo far, our understanding on the role of the auditory cortex (ACX) in processing visual information has been limited to infragranular layers of the ACX, which have been shown to respond to visual stimulation. Here, we investigate the neurons in supragranular layers of the mouse ACX using 2-photon calcium imaging. Contrary to previous reports, here we show that more than 20% of responding neurons in layer2/3 of the ACX respond to full-field visual stimulation. These responses occur by both excitation and hyperpolarization. The primary ACX (A1) has a greater proportion of visual responses by hyperpolarization compared to excitation likely driven by inhibitory neurons of the infragranular layers of the ACX rather than local layer 2/3 inhibitory neurons. Further, we found that more than 60% of neurons in the layer 2/3 of A1 are multisensory in nature. We also show the presence of multisensory neurons in close proximity to exclusive auditory neurons and that there is a reduction in the noise correlations of the recorded neurons during multisensory presentation. This is evidence in favour of deep and intricate visual influence over auditory processing. The results have strong implications for decoding visual influences over the early auditory cortical regions.Significance statementTo understand, what features of our visual world are processed in the auditory cortex (ACX), understanding response properties of auditory cortical neurons to visual stimuli is important. Here, we show the presence of visual and multisensory responses in the supragranular layers of the ACX. Hyperpolarization to visual stimulation is more commonly observed in the primary ACX. Multisensory stimulation results in suppression of responses compared to unisensory stimulation and an overall decrease in noise correlation in the primary ACX. The close-knit architecture of these neurons with auditory specific neurons suggests the influence of non-auditory stimuli on the auditory processing.

scholarly journals Emergence and function of cortical offset responses in sound termination detection

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Magdalena Solyga ◽  
Tania Rinaldi Barkat
Keyword(s):  
Auditory Cortex ◽  
Auditory System ◽  
Auditory Processing ◽  
De Novo ◽  
Central Auditory System ◽  
In Vivo Electrophysiology ◽  
Termination Detection ◽  
Peripheral Auditory System ◽  
And Function

Offset responses in auditory processing appear after a sound terminates. They arise in neuronal circuits within the peripheral auditory system, but their role in the central auditory system remains unknown. Here, we ask what the behavioral relevance of cortical offset responses is and what circuit mechanisms drive them. At the perceptual level, our results reveal that experimentally minimizing auditory cortical offset responses decreases the mouse performance to detect sound termination, assigning a behavioral role to offset responses. By combining in vivo electrophysiology in the auditory cortex and thalamus of awake mice, we also demonstrate that cortical offset responses are not only inherited from the periphery but also amplified and generated de novo. Finally, we show that offset responses code more than silence, including relevant changes in sound trajectories. Together, our results reveal the importance of cortical offset responses in encoding sound termination and detecting changes within temporally discontinuous sounds crucial for speech and vocalization.

scholarly journals Corticothalamic gating of population auditory thalamocortical transmission in mouse

2019 ◽  
Author(s):  
Baher A. Ibrahim ◽  
Caitlin Murphy ◽  
Guido Muscioni ◽  
Aynaz Taheri ◽  
Georgiy Yudintsev ◽  
...  
Keyword(s):  
Receptive Field ◽  
Auditory Cortex ◽  
Cortical Neurons ◽  
Feedback Inhibition ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Linear Filter ◽  
Sensory Stimuli

AbstractSince the discovery of the receptive field, scientists have tracked receptive field structure to gain insights about mechanisms of sensory processing. At the level of the thalamus and cortex, this linear filter approach has been challenged by findings that populations of cortical neurons respond in a stereotyped fashion to sensory stimuli. Here, we elucidate a possible mechanism by which gating of cortical representations occurs. All-or-none population responses (here called “ON” and “OFF” responses) were observed in vivo and in vitro in the mouse auditory cortex at near-threshold acoustic or electrical stimulation. ON-responses were associated with previously-described UP states in the auditory cortex. OFF-responses in the cortex were only eliminated by blocking GABAergic inhibition in the thalamus. Opto- and chemogenetic silencing of NTSR-positive corticothalamic layer 6 (CTL6) neurons as well as the pharmacological blocking of the thalamic reticular nucleus (TRN) retrieved the missing cortical responses, suggesting that the corticothalamic feedback inhibition via TRN controls the gating of thalamocortical activity. Moreover, the oscillation of the pre-stimulus activity of corticothalamic cells predicted the cortical ON vs. OFF responses, suggesting that underlying cortical oscillation controls thalamocortical gating. These data suggest that the thalamus may recruit cortical ensembles rather than linearly encoding ascending stimuli and that corticothalamic projections play a key role in selecting cortical ensembles for activation.

Cerebral Specialization for Speech and Non-Speech Stimuli in Infants

2000 ◽  
Vol 12 (3) ◽  
pp. 449-460 ◽  
Author(s):  
G. Dehaene-Lambertz
Keyword(s):  
Neural Networks ◽  
Auditory Cortex ◽  
Evoked Potentials ◽  
Left Hemisphere ◽  
Auditory Stimulus ◽  
Auditory Processing ◽  
Significant Interaction ◽  
Speech Stimuli ◽  
Acoustic Processing ◽  
The Right

Early cerebral specialization and lateralization for auditory processing in 4-month-old infants was studied by recording high-density evoked potentials to acoustical and phonetic changes in a series of repeated stimuli (either tones or syllables). Mismatch responses to these stimuli exhibit a distinct topography suggesting that different neural networks within the temporal lobe are involved in the perception and representation of the different features of an auditory stimulus. These data confirm that specialized modules are present within the auditory cortex very early in development. However, both for syllables and continuous tones, higher voltages were recorded over the left hemisphere than over the right with no significant interaction of hemisphere by type of stimuli. This suggests that there is no greater left hemisphere involvement in phonetic processing than in acoustic processing during the first months of life.

scholarly journals Emergence and function of cortical offset responses in sound termination detection

2021 ◽  
Author(s):  
Magdalena Sołyga ◽  
Tania Rinaldi Barkat
Keyword(s):  
Auditory Cortex ◽  
Auditory System ◽  
Auditory Processing ◽  
De Novo ◽  
Central Auditory System ◽  
Neuronal Circuits ◽  
Termination Detection ◽  
Peripheral Auditory System ◽  
And Function

Offset responses in auditory processing appear after a sound terminates. They arise in neuronal circuits within the peripheral auditory system, but their role in the central auditory system remains unknown. Here we ask what the behavioural relevance of cortical offset responses is and what circuit mechanisms drive them. At the perceptual level, our results reveal that experimentally minimizing auditory cortical offset responses decreases the mouse performance to detect sound termination, assigning a behavioural role to offset responses. By combining in vivo electrophysiology in the auditory cortex and thalamus of awake mice, we also demonstrate that cortical offset responses are not only inherited from the periphery but also amplified and generated de novo. Finally, we show that offset responses code more than silence, including relevant changes in sound trajectories. Together, our results reveal the importance of cortical offset responses in encoding sound termination and detecting changes within temporally discontinuous sounds crucial for speech and vocalization.

scholarly journals Effects of Acoustic Stimuli on Neuronal Activity in the Auditory Cortex of the Rat

2011 ◽  
pp. 687-693 ◽  
Author(s):  
Y. ZHANG ◽  
L. HAN ◽  
X. XIAO ◽  
B. HU ◽  
H. RUAN ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Auditory Cortex ◽  
Neuronal Activity ◽  
Cortical Neurons ◽  
Slow Wave Sleep ◽  
Sound Stimulus ◽  
Sound Stimulation ◽  
Acoustic Stimuli ◽  
Spontaneous Neuronal Activity

Spontaneous activity of cortical neurons exhibits alternative fluctuations of membrane potential consisting of phased depolarization called "up-state" and persistent hyperpolarization called "down-state" during slow wave sleep and anesthesia. Here, we examined the effects of sound stimuli (noise bursts) on neuronal activity by intracellular recording in vivo from the rat auditory cortex (AC). Noise bursts increased the average time in the up-state by 0.81±0.65 s (range, 0.27-1.74 s) related to a 10 s recording duration. The rise times of the spontaneous up-events averaged 69.41±18.04 ms (range, 40.10-119.21 ms), while those of the sound-evoked up-events were significantly shorter (p<0.001) averaging only 22.54±8.81 ms (range, 9.31-45.74 ms). Sound stimulation did not influence ongoing spontaneous up-events. Our data suggest that a sound stimulus does not interfere with ongoing spontaneous neuronal activity in auditory cortex but can evoke new depolarizations in addition to the spontaneous ones.

Variability and information content in auditory cortex spike trains during an interval-discrimination task

2013 ◽  
Vol 110 (9) ◽  
pp. 2163-2174 ◽  
Author(s):  
Juan M. Abolafia ◽  
M. Martinez-Garcia ◽  
G. Deco ◽  
M. V. Sanchez-Vives
Keyword(s):  
Auditory Cortex ◽  
Information Content ◽  
Auditory Processing ◽  
Cortical Neurons ◽  
Discrimination Task ◽  
Fano Factor ◽  
Information Encoding ◽  
Auditory Responses ◽  
The Right ◽  
Spike Firing

Processing of temporal information is key in auditory processing. In this study, we recorded single-unit activity from rat auditory cortex while they performed an interval-discrimination task. The animals had to decide whether two auditory stimuli were separated by either 150 or 300 ms and nose-poke to the left or to the right accordingly. The spike firing of single neurons in the auditory cortex was then compared in engaged vs. idle brain states. We found that spike firing variability measured with the Fano factor was markedly reduced, not only during stimulation, but also in between stimuli in engaged trials. We next explored if this decrease in variability was associated with an increased information encoding. Our information theory analysis revealed increased information content in auditory responses during engagement compared with idle states, in particular in the responses to task-relevant stimuli. Altogether, we demonstrate that task-engagement significantly modulates coding properties of auditory cortical neurons during an interval-discrimination task.

scholarly journals A versatile and modular tetrode-based device for single-unit recordings in rodent ex vivo and in vivo acute preparations

2020 ◽  
Author(s):  
Francisca Machado ◽  
Nuno Sousa ◽  
Patricia Monteiro ◽  
Luis Jacinto
Keyword(s):  
Auditory Cortex ◽  
Cortical Neurons ◽  
Ex Vivo ◽  
Financial Burden ◽  
Brain Slices ◽  
Single Units ◽  
Single Neurons ◽  
Extracellular Recordings ◽  
Direct Laser

AbstractThe demand for affordable tools for recording extracellular activity and successfully isolating single units from different brain preparations has pushed researchers and companies to invest in developing and fabricating new recording devices. However, depending on the brain region of interest, experimental question or type of preparations, different devices are required thus adding substantial financial burden to laboratories. We have developed a simple and affordable tetrode-based device that allows interchangeable extracellular recordings of neural activity between in vivo and ex vivo preparations and can be easily implemented in all wet-bench laboratories. Spontaneous activity from several putative single neurons could be easily recorded and isolated by lowering the device into ex vivo cerebellum brain slices. The same device was also used in vivo, lowered into primary auditory cortex of adult anesthetized transgenic mice expressing channelrhodopsin in cortical neurons. Acoustic stimulation of the contralateral ear or direct laser optogenetic stimulation successfully evoked cortical activity at the recording site. Several isolated putative single neurons presented time-locked activity response to the different stimuli. In summary, we developed an affordable, versatile and modular device to facilitate tetrode extracellular recordings interchangeably between in vivo anaesthetized animals and ex vivo brain slice recordings.HighlightsDeveloped a versatile and modular device to facilitate tetrode acute brain recordings interchangeably between in vivo and ex vivo preparations.Conducted ex vivo extracellular recordings in acute cerebellar slices.Conducted in vivo extracellular recordings in auditory cortex of anaesthetized mice.Recorded and isolated multiple single units in both acute slices and anaesthetized mice recordings using the same device.Device can be easily extended to accommodate optic fiber and cannula.

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