Neurons in the Thalamic CM-Pf Complex Supply Striatal Neurons With Information About Behaviorally Significant Sensory Events

2001 ◽  
Vol 85 (2) ◽  
pp. 960-976 ◽  
Author(s):  
Naoyuki Matsumoto ◽  
Takafumi Minamimoto ◽  
Ann M. Graybiel ◽  
Minoru Kimura

The projection from the thalamic centre médian–parafascicular (CM-Pf) complex to the caudate nucleus and putamen forms a massive striatal input system in primates. We examined the activity of 118 neurons in the CM and 62 neurons in the Pf nuclei of the thalamus and 310 tonically active neurons (TANs) in the striatum in awake behaving macaque monkeys and analyzed the effects of pharmacologic inactivation of the CM-Pf on the sensory responsiveness of the striatal TANs. A large proportion of CM and Pf neurons responded to visual (53%) and/or auditory beep (61%) or click (91%) stimuli presented in behavioral tasks, and many responded to unexpected auditory, visual, or somatosensory stimuli presented outside the task context. The neurons fell into two classes: those having short-latency facilitatory responses (SLF neurons, predominantly in the Pf) and those having long-latency facilitatory responses (LLF neurons, predominantly in the CM). Responses of both types of neuron appeared regardless of whether or not the sensory stimuli were associated with reward. These response characteristics of CM-Pf neurons sharply contrasted with those of TANs in the striatum, which under the same conditions responded preferentially to stimuli associated with reward. Many CM-Pf neurons responded to alerting stimuli such as unexpected handclaps and noises only for the first few times that they occurred; after that, the identical stimuli gradually became ineffective in evoking responses. Habituation of sensory responses was particularly common for the LLF neurons. Inactivation of neuronal activity in the CM and Pf by local infusion of the GABAA receptor agonist, muscimol, almost completely abolished the pause and rebound facilitatory responses of TANs in the striatum. Such injections also diminished behavioral responses to stimuli associated with reward. We suggest that neurons in the CM and Pf supply striatal neurons with information about behaviorally significant sensory events that can activate conditional responses of striatal neurons in combination with dopamine-mediated nigrostriatal inputs having motivational value.

2009 ◽  
Vol 102 (1) ◽  
pp. 437-450 ◽  
Author(s):  
Akio Hirata ◽  
Juan Aguilar ◽  
Manuel A. Castro-Alamancos

Influence of subcortical inhibition on barrel cortex receptive fields. By the time neural responses driven by vibrissa stimuli reach the barrel cortex, they have undergone significant spatial and temporal transformations within subcortical relays. A major regulator of these transformations is thought to be subcortical GABA-mediated inhibition, but the actual degree of this influence is unknown. We used disinhibition produced by GABA receptor antagonists to unmask the excitatory sensory responses that are normally suppressed by inhibition in the main subcortical sensory relays to barrel cortex; principal trigeminal (Pr5) and primary thalamic (VPM) nuclei. We found that, within subcortical relays, inhibition only slightly suppresses short-latency receptive field responses, but robustly suppresses long-latency center and surround receptive field responses. However, the long-latency subcortical effects of inhibition are mostly not reflected in the barrel cortex. The most robust effect of subcortical inhibition on barrel cortex responses is to transiently suppress the receptive field responses of high-frequency sensory stimuli. This transient adaptation caused by subcortical inhibition recovers within a few stimuli and gives way to a steady-state adaptation that is independent of subcortical inhibition.


2015 ◽  
Vol 113 (1) ◽  
pp. 58-70 ◽  
Author(s):  
Nico A. Jansen ◽  
Glenn J. Giesler

We tested the possibility that the trigeminoparabrachial tract (VcPbT), a projection thought to be importantly involved in nociception, might also contribute to sensation of itch. In anesthetized rats, 47 antidromically identified VcPbT neurons with receptive fields involving the cheek were characterized for their responses to graded mechanical and thermal stimuli and intradermal injections of pruritogens (serotonin, chloroquine, and β-alanine), partial pruritogens (histamine and capsaicin), and an algogen (mustard oil). All pruriceptive VcPbT neurons were responsive to mechanical stimuli, and more than half were additionally responsive to thermal stimuli. The majority of VcPbT neurons were activated by injections of serotonin, histamine, capsaicin, and/or mustard oil. A subset of neurons were inhibited by injection of chloroquine. The large majority of VcPbT neurons projected to the ipsilateral and/or contralateral external lateral parabrachial and Kölliker-Fuse nuclei, as evidenced by antidromic mapping techniques. Analyses of mean responses and spike-timing dynamics of VcPbT neurons suggested clear differences in firing rates between responses to noxious and pruritic stimuli. Comparisons between the present data and those previously obtained from trigeminothalamic tract (VcTT) neurons demonstrated several differences in responses to some pruritogens. For example, responses of VcPbT neurons to injection of serotonin often endured for nearly an hour and showed a delayed peak in discharge rate. In contrast, responses of VcTT neurons endured for roughly 20 min and no delayed peak of firing was noted. Thus the longer duration responses to 5-HT and the delay in peak firing of VcPbT neurons better matched behavioral responses to stimulation in awake rats than did those of VcTT neurons. The results indicate that VcPbT neurons may have important roles in the signaling of itch as well as pain.


2004 ◽  
Vol 92 (1) ◽  
pp. 361-371 ◽  
Author(s):  
Janusz Rajkowski ◽  
Henryk Majczynski ◽  
Edwin Clayton ◽  
Gary Aston-Jones

We previously reported that noradrenergic neurons in the monkey locus coeruleus (LC) are activated selectively by target stimuli in a target detection task. Here, we varied the discrimination difficulty in this task and recorded impulse activity of LC neurons to analyze LC responses on error trials and in relation to behavioral response times (RTs). In easy and difficult discrimination conditions, LC neurons responded preferentially to target stimuli with phasic activation. These responses consistently preceded behavioral responses regardless of task difficulty. Latencies for LC and behavioral responses increased similarly for difficult compared with easy discrimination trials. LC response latencies were also shorter for fast RT trials compared with slow RT trials regardless of difficulty, indicating a close temporal relationship between LC and behavioral responses. This relationship was confirmed with response-locked histograms of LC activity, which yielded more temporally synchronized LC responses than stimulus-locked histograms. Population histograms of LC activity revealed that nontarget stimuli resulting in false alarm responses produced phasic LC activation (although smaller than for target-hit trials), and nontarget stimuli resulting in correct rejection responses yielded a small inhibition in LC activity. Population analyses also revealed that LC responses included an early, small excitatory component that was not previously detected. This early response was nondiscriminative because it was similar for target and nontarget stimulus trials. These results indicate that LC neurons exhibit early small magnitude responses that are closely linked to sensory stimuli. In addition, these cells show a later, larger magnitude response that is temporally linked to behavioral responses. These and other results lead us to hypothesize that LC responses are driven by decision processes and help facilitate subsequent behavioral responses.


2007 ◽  
Vol 97 (4) ◽  
pp. 2992-3003 ◽  
Author(s):  
Aren J. Borgdorff ◽  
James F. A. Poulet ◽  
Carl C. H. Petersen

The sensory responses in the barrel cortex of mice aged postnatal day (P)7–P12 evoked by a single whisker deflection are smaller in amplitude and spread over a smaller area than those measured in P13–P21 mice. However, repetitive 10-Hz stimulation or paired pulse whisker stimulation in P7–P12 mice evoked facilitating sensory responses, contrasting with the depressing sensory responses observed in P13–P21 mice. This facilitation occurred during an interval ranging 300–1,000 ms after the first stimulus and was measured using whole cell recordings, voltage-sensitive dye imaging, and calcium-sensitive dye imaging. The facilitated responses were not only larger in amplitude but also propagated over a larger cortical area. The facilitation could be blocked by local application of pharmacological agents reducing cortical excitability. Local cortical microstimulation could substitute for the first whisker stimulus to produce a facilitated sensory response. The enhanced sensory responses evoked by repetitive sensory stimuli in P7–P12 mice may contribute to the activity-dependent specification of the developing cortical circuits. In addition, the facilitating sensory responses allow long integration times for sensory processing compatible with the slow behavior of mice during early postnatal development.


2019 ◽  
Author(s):  
Mark Aizenberg ◽  
Solymar Rolon Martinez ◽  
Tuan Pham ◽  
Winnie Rao ◽  
Julie Haas ◽  
...  

AbstractMany forms of behavior require selective amplification of neuronal representations of relevant environmental signals. Following emotional learning, sensory stimuli drive enhanced responses in the sensory cortex. However, the brain circuits that underlie emotionally driven control of the sensory representations remain poorly understood. Here we identify a novel pathway between the basolateral amygdala (BLA), an emotional learning center in the mouse brain, and the inhibitory nucleus of the thalamus (TRN). We demonstrate that activation of this pathway amplifies sound-evoked activity in the central auditory pathway. Optogenetic activation of BLA suppressed spontaneous, but not tone-evoked activity in the auditory cortex (AC), effectively amplifying tone-evoked responses in AC. Anterograde and retrograde viral tracing identified robust BLA projections terminating at TRN. Optogenetic activation of amygdala-TRN pathway mimicked the effect of direct BLA activation, amplifying tone-evoked responses in the auditory thalamus and cortex. The results are explained by a computational model of the thalamocortical circuitry. In our model, activation of TRN by BLA suppresses spontaneous activity in thalamocortical cells, and as a result, thalamocortical neurons are primed to relay relevant sensory input. These results demonstrate a novel circuit mechanism for shining a neural spotlight on behaviorally relevant signals and provide a potential target for treatment of neuropsychological disorders, in which emotional control of sensory processing is disrupted.


2021 ◽  
Author(s):  
Deepa L Ramamurthy ◽  
Andrew Chen ◽  
Patrick C Huang ◽  
Priyanka Bharghavan ◽  
Gayathri Krishna ◽  
...  

Vasoactive intestinal peptide-expressing (VIP) interneurons, which constitute 10-15% of the cortical inhibitory neuron population, have emerged as an important cell type for regulating excitatory cell activity based on behavioral state. VIP cells in sensory cortex are potently engaged by neuromodulatory and motor inputs during active exploratory behaviors like locomotion and whisking, which in turn promote pyramidal cell firing via disinhibition. Such state-dependent modulation of activity by VIP cells in sensory cortex has been studied widely in recent years. However, the function of VIP cells during goal-directed behavior is less well understood. It is not clear how task-related events like sensory stimuli, motor actions, or reward activate VIP cells in sensory cortex since there is often temporal overlap in the occurrence of these events. We developed a Go/NoGo whisker touch detection task which incorporates a post-stimulus delay period to separate sensory-driven activity from action- or reward-related activity during behavior. We used 2-photon calcium imaging to measure task-related signals of L2/3 VIP neurons in S1 of behaving mice. We report for the first time that VIP cells in mouse whisker S1 are activated by both whisker stimuli and goal-directed licking. Whisker- and lick-related signals were spatially organized in relation to anatomical columns in S1. Sensory responses of VIP cells were tuned to specific whiskers, whether or not they also displayed lick-related activity.


Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 35-35 ◽  
Author(s):  
M T Wallace

Multisensory integration in the superior colliculus (SC) of the cat requires a protracted postnatal developmental time course. Kittens 3 – 135 days postnatal (dpn) were examined and the first neuron capable of responding to two different sensory inputs (auditory and somatosensory) was not seen until 12 dpn. Visually responsive multisensory neurons were not encountered until 20 dpn. These early multisensory neurons responded weakly to sensory stimuli, had long response latencies, large receptive fields, and poorly developed response selectivities. Most striking, however, was their inability to integrate cross-modality cues in order to produce the significant response enhancement or depression characteristic of these neurons in adults. The incidence of multisensory neurons increased gradually over the next 10 – 12 weeks. During this period, sensory responses became more robust, latencies shortened, receptive fields decreased in size, and unimodal selectivities matured. The first neurons capable of cross-modality integration were seen at 28 dpn. For the following two months, the incidence of such integrative neurons rose gradually until adult-like values were achieved. Surprisingly, however, as soon as a multisensory neuron exhibited this capacity, most of its integrative features were indistinguishable from those in adults. Given what is known about the requirements for multisensory integration in adult animals, this observation suggests that the appearance of multisensory integration reflects the onset of functional corticotectal inputs.


1995 ◽  
Vol 104 (12) ◽  
pp. 928-935 ◽  
Author(s):  
Christy L. Ludlow ◽  
Toshiyuki Yamashita ◽  
Geralyn M. Schulz ◽  
Frederic W.-B. Deleyiannis

Sensorimotor responses to repeated electrical stimulation of the superior laryngeal nerve were compared in 8 patients with adductor spasmodic dysphonia (ADSD) and 11 normal controls to determine if adductor response disinhibition occurred in ADSD. Pairs of electrical pulses were presented at interstimulus intervals varying from 100 to 5,000 milliseconds (ms). Three responses were measured in thyroarytenoid muscles: ipsilateral R1 responses at 17 ms and ipsilateral and contralateral R2 responses between 60 and 75 ms. Conditioned response characteristics, the percent occurrence and percentage amplitude of initial responses, were measures of response inhibition. As a group, the patients had reduced response inhibition: their conditioned ipsilateral R1 response amplitudes were increased, as was the frequency of their conditioned contralateral muscle responses (p ⩽ .002) compared to normal. However, the patients' initial responses were normal in latency and frequency characteristics, demonstrating that the brain stem mechanisms for these responses were intact. These results suggest a central disinhibition of laryngeal responses to sensory input in ADSD.


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