Information flow of spontaneous and auditory-evoked neural activity in the rat thalamo-cortical system

2021 ◽  
Author(s):  
Kotaro Ishizu ◽  
Tomoyo I. Shiramatsu ◽  
Rie Hitsuyu ◽  
Masafumi Oizumi ◽  
Naotsugu Tsuchiya ◽  
...  
Keyword(s):  
Information Flow ◽  
Neural Activity ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Stimulus Presentation ◽  
Dynamic Information ◽  
Information Theoretic ◽  
Medial Geniculate ◽  
Cortical System ◽  
Source Of Information

Abstract The interaction between the thalamus and sensory cortex plays critical roles in sensory processing. Previous studies have revealed pathway-specific synaptic properties of thalamo-cortical connections. However, few studies to date have investigated how each pathway routes moment-to-moment information. Here, we simultaneously recorded neural activity in the auditory thalamus (or ventral division of the medial geniculate body; MGv) and primary auditory cortex (A1) with a laminar resolution in anesthetized rats. Transfer entropy (TE) was used as an information theoretic measure to operationalize “information flow”. Our analyses confirmed that communication between the thalamus and cortex was strengthened during presentation of auditory stimuli. In the resting state, thalamo-cortical communications almost disappeared, whereas cortico-cortical communications were strengthened. The predominant source of information was the MGv at the onset of stimulus presentation and layer 5 during spontaneous activity. In turn, MGv was the major recipient of information from layer 6. TE suggested that a small but significant population of MGv-to-A1 pairs was “information-bearing,” whereas A1-to-MGv pairs typically exhibiting small effects played modulatory roles. These results highlight the capability of TE analyses to unlock novel avenues for bridging the gap between well-established anatomical knowledge of canonical microcircuits and physiological correlates via the concept of dynamic information flow.

scholarly journals Information flow in the rat thalamo-cortical system: spontaneous vs. stimulus-evoked activities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kotaro Ishizu ◽  
Tomoyo I. Shiramatsu ◽  
Rie Hitsuyu ◽  
Masafumi Oizumi ◽  
Naotsugu Tsuchiya ◽  
...  
Keyword(s):  
Information Flow ◽  
Sensory Processing ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Stimulus Presentation ◽  
Dynamic Information ◽  
Information Theoretic ◽  
Medial Geniculate ◽  
Cortical System ◽  
Source Of Information

AbstractThe interaction between the thalamus and sensory cortex plays critical roles in sensory processing. Previous studies have revealed pathway-specific synaptic properties of thalamo-cortical connections. However, few studies to date have investigated how each pathway routes moment-to-moment information. Here, we simultaneously recorded neural activity in the auditory thalamus (or ventral division of the medial geniculate body; MGv) and primary auditory cortex (A1) with a laminar resolution in anesthetized rats. Transfer entropy (TE) was used as an information theoretic measure to operationalize “information flow”. Our analyses confirmed that communication between the thalamus and cortex was strengthened during presentation of auditory stimuli. In the resting state, thalamo-cortical communications almost disappeared, whereas intracortical communications were strengthened. The predominant source of information was the MGv at the onset of stimulus presentation and layer 5 during spontaneous activity. In turn, MGv was the major recipient of information from layer 6. TE suggested that a small but significant population of MGv-to-A1 pairs was “information-bearing,” whereas A1-to-MGv pairs typically exhibiting small effects played modulatory roles. These results highlight the capability of TE analyses to unlock novel avenues for bridging the gap between well-established anatomical knowledge of canonical microcircuits and physiological correlates via the concept of dynamic information flow.

scholarly journals Selective Corticofugal Modulation on Sound Processing in Auditory Thalamus of Awake Marmosets

2021 ◽  
Author(s):  
Yuanqing Zhang ◽  
Xiaohui Wang ◽  
Lin Zhu ◽  
Siyi Bai ◽  
Rui Li ◽  
...  
Keyword(s):  
Sensory Processing ◽  
Frequency Tuning ◽  
Signal To Noise Ratio ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Medial Geniculate ◽  
Auditory Response ◽  
Corticofugal Feedback ◽  
Corticothalamic Feedback

Cortical feedback has long been considered crucial for modulation of sensory processing. In the mammalian auditory system, studies have suggested that corticofugal feedback can have excitatory, inhibitory, or both effects on the response of subcortical neurons, leading to controversies regarding the role of corticothalamic influence. This has been further complicated by studies conducted under different brain states. In the current study, we used cryo-inactivation in the primary auditory cortex (A1) to examine the role of corticothalamic feedback on medial geniculate body (MGB) neurons in awake marmosets. The primary effects of A1 inactivation were a frequency-specific decrease in the auditory response of MGB neurons coupled with an increased spontaneous firing rate, which together resulted in a decrease in the signal-to-noise ratio. In addition, we report for the first-time that A1 robustly modulated the long-lasting sustained response of MGB neurons which changed the frequency tuning after A1 inactivation, e.g., neurons with sharp tuning increased tuning bandwidth whereas those with broad tuning decreased tuning bandwidth. Taken together, our results demonstrate that corticothalamic modulation in awake marmosets serves to enhance sensory processing in a way similar to center-surround models proposed in visual and somatosensory systems, a finding which supports common principles of corticothalamic processing across sensory systems.

scholarly journals Auditory Edge Detection: A Neural Model for Physiological and Psychoacoustical Responses to Amplitude Transients

2001 ◽  
Vol 85 (6) ◽  
pp. 2303-2323 ◽  
Author(s):  
Alon Fishbach ◽  
Israel Nelken ◽  
Yehezkel Yeshurun
Keyword(s):  
Edge Detection ◽  
Auditory System ◽  
Physiological Responses ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Neural Model ◽  
Perceptual Task ◽  
Edge Detector ◽  
Medial Geniculate ◽  
First Time

Primary segmentation of visual scenes is based on spatiotemporal edges that are presumably detected by neurons throughout the visual system. In contrast, the way in which the auditory system decomposes complex auditory scenes is substantially less clear. There is diverse physiological and psychophysical evidence for the sensitivity of the auditory system to amplitude transients, which can be considered as a partial analogue to visual spatiotemporal edges. However, there is currently no theoretical framework in which these phenomena can be associated or related to the perceptual task of auditory source segregation. We propose a neural model for an auditory temporal edge detector, whose underlying principles are similar to classical visual edge detector models. Our main result is that this model reproduces published physiological responses to amplitude transients collected at multiple levels of the auditory pathways using a variety of experimental procedures. Moreover, the model successfully predicts physiological responses to a new set of amplitude transients, collected in cat primary auditory cortex and medial geniculate body. Additionally, the model reproduces several published psychoacoustical responses to amplitude transients as well as the psychoacoustical data for amplitude edge detection reported here for the first time. These results support the hypothesis that the response of auditory neurons to amplitude transients is the correlate of psychoacoustical edge detection.

scholarly journals Antidromic Activation Reveals Tonotopically Organized Projections From Primary Auditory Cortex to the Central Nucleus of the Inferior Colliculus in Guinea Pig

2007 ◽  
Vol 97 (2) ◽  
pp. 1413-1427 ◽  
Author(s):  
Hubert H. Lim ◽  
David J. Anderson
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Spatial Organization ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Central Nucleus ◽  
Antidromic Activation ◽  
Antidromic Stimulation ◽  
Medial Geniculate ◽  
Layer V

The inferior colliculus (IC) is highly modulated by descending projections from higher auditory and nonauditory centers. Traditionally, corticofugal fibers were believed to project mainly to the extralemniscal IC regions. However, there is some anatomical evidence suggesting that a substantial number of fibers from the primary auditory cortex (A1) project into the IC central nucleus (ICC) and appear to be tonotopically organized. In this study, we used antidromic stimulation combined with other electrophysiological techniques to further investigate the spatial organization of descending fibers from A1 to the ICC in ketamine-anesthetized guinea pigs. Based on our findings, corticofugal fibers originate predominantly from layer V of A1, are amply scattered throughout the ICC and only project to ICC neurons with a similar best frequency (BF). This strict tonotopic pattern suggests that these corticofugal projections are involved with modulating spectral features of sound. Along the isofrequency dimension of the ICC, there appears to be some differences in projection patterns that depend on BF region and possibly isofrequency location within A1 and may be indicative of different descending coding strategies. Furthermore, the success of the antidromic stimulation method in our study demonstrates that it can be used to investigate some of the functional properties associated with corticofugal projections to the ICC as well as to other regions (e.g., medial geniculate body, cochlear nucleus). Such a method can address some of the limitations with current anatomical techniques for studying the auditory corticofugal system.

Differential Distribution of Burst and Single-Spike Responses in Auditory Thalamus

2002 ◽  
Vol 88 (4) ◽  
pp. 2152-2156 ◽  
Author(s):  
Jufang He ◽  
Bin Hu
Keyword(s):  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Noise Burst ◽  
Auditory Information ◽  
Differential Distribution ◽  
Firing Patterns ◽  
Auditory Thalamus ◽  
Single Spike ◽  
Medial Geniculate ◽  
Low Threshold

The medial geniculate body (MGB) of the auditory thalamus comprises lemniscal and nonlemniscal neurons that project to the primary auditory cortex and limbic structures, respectively. Here we show that in anesthetized guinea pigs, MGB responses to a noise-burst stimulus exhibit distinct and synaptic pathway-specific firing patterns. The majority of nonlemniscal MGB cells exhibited bursting responses, whereas lemniscal neurons discharged mainly single or spike doublets. The burst firing is delayed in nonlemniscal neurons and exhibited several features that are characteristics of those mediated by low-threshold Ca2+ spikes. Such a synaptic pathway-specific allocation of bursting and single-spike firing patterns is consistent with the notion of parallel processing of auditory information in thalamocortical system.

Comparison of noise and tone azimuth tuning of neurons in cat primary auditory cortex and medical geniculate body

1995 ◽  
Vol 74 (3) ◽  
pp. 961-980 ◽  
Author(s):  
J. C. Clarey ◽  
P. Barone ◽  
W. A. Irons ◽  
F. K. Samson ◽  
T. J. Imig
Keyword(s):  
Auditory Cortex ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Broadband Noise ◽  
Statistical Analyses ◽  
Data Set ◽  
Degree Elevation ◽  
Level Data ◽  
Medial Geniculate ◽  
Ventral Nucleus

1. A comparison of the azimuth tuning of single neurons to broadband noise and to best frequency (BF) tone bursts was made in primary auditory cortex (AI: n = 173) and the medial geniculate body (MGB: n = 52) of barbiturate-anesthetized cats. Observations were largely restricted to cells located within the tonotopically organized divisions of the MGB (i.e., the ventral nucleus and the lateral division of the posterior nuclear group) and the middle layers of AI. All cells studied had BFs > or = 4 kHz. 2. The responses of each cell to sounds presented from seven frontal azimuthal locations (-90 to +90 degrees in 30 degrees steps; 0 degree elevation) and at five sound pressure levels (SPLs: 0-80 dB or 5-85 dB in 20-dB steps) provided an azimuth-level data set. Responses were averaged over SPL to obtain an azimuth function, and a number of features of this function were used to describe azimuth tuning to noise and to tone stimulation. Azimuth function modulation was used to assess azimuth sensitivity, and cells were categorized as sensitive or insensitive depending on whether modulation was > or = 75% or < 75% of maximum, respectively. The majority (88%) of cells in the sample were azimuth sensitive to noise stimulation, and statistical analyses were restricted to these cells, which are presumably best suited to encode sound source azimuth. Azimuth selectivity was assessed by a preferred azimuth range (PAR) over which azimuth function values exceeded 75% (PAR75) or 50% of maximum response. Cells were categorized according to the location and extent of their noise PARs. Unbounded cells had laterally located PARs that extended to the lateral pole (+/- 90 degrees); bounded cells had PARs that were contained entirely within the frontal hemifield, and a subset of these had PARs centered on the midline (+/- 15 degrees). A final group of cells exhibited multipeaked azimuth functions to noise stimulation. 3. Azimuth functions to noise were generally more selective and/or more sensitive than those to tones. Statistical analyses showed that these differences were significant for cells in each azimuth function category, and for the thalamic and cortical samples. With the exception of multipeaked cells, responsiveness to noise was significantly lower than that to tones in all categories, and for the thalamic and cortical samples.(ABSTRACT TRUNCATED AT 400 WORDS)

Origins of medial geniculate body projections to physiologically defined zones of rat primary auditory cortex

1999 ◽  
Vol 130 (1-2) ◽  
pp. 42-61 ◽  
Author(s):  
Jeffery A Winer ◽  
Sharon L Sally ◽  
David T Larue ◽  
Jack B Kelly
Keyword(s):  
Auditory Cortex ◽  
Medial Geniculate Body ◽  
Primary Auditory Cortex ◽  
Medial Geniculate
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