Response properties of single units in areas of rat auditory thalamus that project to the amygdala

1994 ◽  
Vol 98 (2) ◽  
pp. 275-286 ◽  
Author(s):  
Fabio Bordi ◽  
Joseph E. LeDoux
2020 ◽  
Author(s):  
Hemant K Srivastava ◽  
Sharba Bandyopadhyay

AbstractThe orbitofrontal cortex (OFC), controls flexible behavior through stimulus value updating based on stimulus outcome associations, allowing seamless navigation in dynamic sensory environments with changing contingencies. Sensory cue driven responses, primarily studied through behavior, exist in the OFC. However, OFC neurons’ sensory response properties, particularly auditory, are unknown, in the mouse, a genetically tractable animal. We show that mouse OFC single neurons have unique auditory response properties showing pure deviance detection and long timescales of adaptation resulting in stimulus-history dependence. Further, we show that OFC auditory responses are shaped by two parallel sources in the auditory thalamus, lemniscal and non-lemniscal. The latter underlies a large component of the observed deviance detection and additionally controls persistent activity in the OFC through the amygdala. The deviant selectivity can serve as a signal for important changes in the auditory environment. Such signals if coupled with persistent activity, obtained by disinhibitory control from the non-lemniscal auditory thalamus or the amygdala, will allow for associations with a delayed outcome related signal, like reward prediction error, and potentially forms the basis of updating stimulus outcome associations in the OFC. Thus the baseline sensory responses allow the behavioral requirement based response modification through relevant inputs from other structures related to reward, punishment, or memory. Thus, alterations in these responses in neurological disorders can lead to behavioral deficits.


2011 ◽  
Vol 105 (6) ◽  
pp. 2647-2667 ◽  
Author(s):  
Edward L. Bartlett ◽  
Xiaoqin Wang

As the information bottleneck of nearly all auditory input that reaches the cortex, the auditory thalamus serves as the basis for establishing auditory cortical processing streams. The functional organization of the primary and nonprimary subdivisions of the auditory thalamus is not well characterized, particularly in awake primates. We have recorded from neurons in the auditory thalamus of awake marmoset monkeys and tested their responses to tones, band-pass noise, and temporally modulated stimuli. We analyzed the spectral and temporal response properties of recorded neurons and correlated those properties with their locations in the auditory thalamus, thereby forming the basis for parallel output channels. Three medial geniculate body (MGB) subdivisions were identified and studied physiologically and anatomically, although other medial subdivisions were also identified anatomically. Neurons in the ventral subdivision (MGV) were sharply tuned for frequency, preferred narrowband stimuli, and were able to synchronize to rapid temporal modulations. Anterodorsal subdivision (MGAD) neurons appeared well suited for temporal processing, responding similarly to tone or noise stimuli but able to synchronize to the highest modulation frequencies and with the highest temporal precision among MGB subdivisions. Posterodorsal subdivision (MGPD) neurons differed substantially from the other two subdivisions, with many neurons preferring broadband stimuli and signaling changes in modulation frequency with nonsynchronized changes in firing rate. Most neurons in all subdivisions responded to increases in tone sound level with nonmonotonic changes in firing rate. MGV and MGAD neurons exhibited responses consistent with provision of thalamocortical input to core regions, whereas MGPD neurons were consistent with provision of input to belt regions.


1976 ◽  
Vol 16 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Kathleen S. Mayers ◽  
Richard T. Robertson ◽  
Timothy J. Teyler ◽  
Richard F. Thompson

1993 ◽  
Vol 69 (3) ◽  
pp. 842-859 ◽  
Author(s):  
E. Covey

1. Connectional evidence suggests that the dorsal nucleus of the lateral lemniscus (DNLL) and the paralemniscal zone (PL) function as centers for binaural analysis interposed between the superior olivary complex and the midbrain. In addition, the DNLL is known to be a major source of inhibitory input to the midbrain. The aim of this study was to characterize the response properties of neurons in DNLL and PL of the echolocating bat Eptesicus fuscus, a species that utilizes high-frequency hearing and that might be expected to have a large proportion of neurons responsive to interaural differences in sound level. 2. Auditory stimuli were presented monaurally or binaurally to awake animals, and responses of single units were recorded extra-cellularly with the use of glass micropipettes. 3. Below the ventrolateral border of the inferior colliculus is a region that contains large gamma-aminobutyric acid-positive neurons. On the basis of its immunohistochemical reactivity, this entire region could be considered as DNLL. However, within the area, there was an uneven distribution of binaural responses. Caudally, binaural neurons made up 84% (41/49) of those tested, but rostrally only 29% (6/21). For this reason the rostral area is considered as a separate functional subdivision and referred to as the dorsal paralemniscal zone (DPL). PL is located ventral to DPL and medial to the intermediate and ventral nuclei of the lateral lemniscus; in PL 88% (14/16) of neurons were binaural. 4. Most neurons responded only to a contralateral stimulus when sounds were presented monaurally. Out of 49 neurons in DNLL, 42 responded only to a contralateral sound, 1 responded only to an ipsilateral sound, and 6 responded to sound at either ear. In the DPL, all of the 21 neurons tested responded to a contralateral sound and none to an ipsilateral sound. Out of 16 neurons in the PL, 11 responded only to a contralateral sound, 1 responded only to an ipsilateral sound, and 4 responded to sound at either ear. 5. When sounds were presented at both ears simultaneously, several different patterns of binaural interaction occurred. The most common pattern was suppression of the response to sound at one ear by sound at the other ear. In DNLL, 57% (28/49) of neurons showed this type of binaural interaction. Another 10% (5/49) showed facilitation at some interaural level differences and suppression at others, and another 10% (5/49) showed facilitation at some interaural level differences but no suppression.(ABSTRACT TRUNCATED AT 400 WORDS)


1997 ◽  
Vol 77 (4) ◽  
pp. 2083-2097 ◽  
Author(s):  
S. Ghoshal ◽  
D. O. Kim

Ghoshal, S. and D. O. Kim. Marginal shell of the anteroventral cochlear nucleus: single-unit response properties in the unanesthetized decerebrate cat. J. Neurophysiol. 77: 2083–2097, 1997. The marginal shell of the anteroventral cochlear nucleus (AVCN) is anatomically different from its central core. We investigated 38 single units in the shells of 10 cats and contrasted them with 62 single units in the cores of 15 cats. The sites of all shell units were localized with the use of reconstructed electrode tracks. The shell units were divided into acoustically well-driven (68%) and weakly/not-driven (32%) subgroups. The shell units mostly exhibited low spontaneous rates (SRs). Among the well-driven shell units, a large majority (68%) exhibited wide dynamic ranges (≥50 dB) to tones, noise, or both, with some ranges as wide as 89 dB. In contrast, a large majority (80%) of the core units exhibited narrow dynamic ranges (<50 dB) to tones and noise. The poststimulus time histograms (PSTHs) of the well-driven shell units included pause-build (29%), onset (24%), and unusual (33%) types, whereas those of the core units included mainly primary-like (47%) and chopper (29%) types. The excitatory-inhibitory areas (EIAs) of the well-driven shell units included types I/III (47%), III (22%), IV (13%), and II (9%), whereas those of the core units included mainly types III (52%) and I/III (32%). On the basis of Fisher's exact tests, we conclude that the shell and core neural groups of the AVCN are significantly different regarding all of the following physiological characteristics: SR, maximum driven rate, threshold and dynamic range to tones and noise, frequency response area, PSTH type, latency, and EIA type. Wide dynamic ranges of the well-driven shell units suggest that they may play a role in encoding absolute intensity of acoustic stimulus.


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