Source Paper
Giant neurons in the rat reticular formation: a sensorimotor interface in the elementary acoustic startle circuit?
K Lingenhohl, E Friauf
Journal of Neuroscience • 1994
Source Paper
K Lingenhohl, E Friauf
Journal of Neuroscience • 1994
The mammalian acoustic startle response (ASR) is a relatively simple motor response that can be elicited by sudden and loud acoustic stimuli. The ASR shows several forms of plasticity, such as habituation, sensitization, and prepulse inhibition, thereby making it an interesting model for studying the underlying neuronal mechanisms. Among the neurons that compose the elementary startle circuit are giant neurons in the caudal pontine reticular nucleus (PnC), which may be good candidates for analyzing the neuronal basis of mammalian behavior. In a first step of this study, we employed retrograde and anterograde tracing techniques to identify the possible sources of input and the efferent targets of these neurons. In a second step, we performed intracellular recordings in vivo, followed by subsequent injections of HRP for morphological identification, thereby investigating whether characteristic features of the ASR are reflected by physiological properties of giant PnC neurons. Our observations demonstrate convergent, bilateral input from several auditory brainstem nuclei to the PnC, predominantly originating from neurons in the cochlear nuclear complex and the superior olivary complex. Almost no input neurons were found in the nuclei of the lateral lemniscus. As the relatively long neuronal response latencies in several of these auditory nuclei appear to be incompatible with the primary ASR, we conclude that neurons in the cochlear root nuclei most likely provide the auditory input to PnC neurons that is required to elicit the ASR. The giant PnC neurons have a remarkable number of physiological features supporting the hypothesis that they may be a neural correlate of the ASR: (1) they receive short- latency auditory input, (2) they have high firing thresholds and broad frequency tuning, (3) they are sensitive to changes in stimulus rise time and to paired-pulse stimulation, (4) repetitive acoustic stimulation results in habituation of their response, and (5) amygdaloid activity enhances their response to acoustic stimuli. Anterograde tracing showed that most giant PnC neurons are reticulospinal cells. Axon collaterals and terminal arbors were found in the reticular formation as well as in cranial and spinal motoneuron pools. The results of this study indicate that giant PnC neurons form a sensorimotor interface between the cochlear nuclear complex and cranial and spinal motoneurons. This neuronal pathway implies that the elementary acoustic startle circuit is composed of only three central relay stations and thus appears to be organized more simply than assumed in the past.
Objective: Characterize physiological properties of giant PnC neurons in response to acoustic stimuli including response latencies, thresholds, frequency tuning, and habituation to understand the neuronal basis of the acoustic startle response
This is a Acoustic Startle Response Characterization protocol using rat as the model organism. The procedure involves 10 procedural steps, 2 equipment items, 1 materials. Extracted from a 1994 paper published in Journal of Neuroscience.
Model and subjects
rat • not specified • unknown • not specified • not specified
Study window
Estimated timing pending
Core workflow
Retrograde and anterograde tracing • Intracellular recording in vivo • Measure response latencies
Primary readouts
Key equipment and reagents
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Employ retrograde and anterograde tracing techniques to identify possible sources of input and efferent targets of giant PnC neurons
Note: First step of the study to map connectivity
“In a first step of this study, we employed retrograde and anterograde tracing techniques to identify the possible sources of input and the efferent targets of these neurons”
Perform intracellular recordings from giant PnC neurons in vivo to investigate physiological properties in response to acoustic stimuli
Note: Recordings followed by HRP injection for morphological identification
“In a second step of this study, we performed intracellular recordings in vivo, followed by subsequent injections of HRP for morphological identification”
Measure the latency of neuronal responses to acoustic stimuli in giant PnC neurons
Note: Response latencies are a key characteristic feature of the ASR
“they receive short-latency auditory input”
Determine the firing thresholds of giant PnC neurons in response to acoustic stimuli
Note: Giant PnC neurons have high firing thresholds
“they have high firing thresholds and broad frequency tuning”
Analyze the frequency tuning properties of giant PnC neurons across different acoustic frequencies
Note: Neurons show broad frequency tuning
“they have high firing thresholds and broad frequency tuning”
Assess sensitivity of giant PnC neurons to changes in stimulus rise time of acoustic stimuli
Note: Neurons are sensitive to stimulus rise time variations
“they are sensitive to changes in stimulus rise time and to paired-pulse stimulation”
Apply paired acoustic pulses to assess neuronal sensitivity to paired-pulse stimulation
Note: Neurons respond to paired-pulse stimulation patterns
“they are sensitive to changes in stimulus rise time and to paired-pulse stimulation”
Apply repetitive acoustic stimulation and measure habituation of neuronal responses over time
Note: Repetitive acoustic stimulation results in habituation of response
“repetitive acoustic stimulation results in habituation of their response”
Assess whether amygdaloid activity enhances the response of giant PnC neurons to acoustic stimuli
Note: Amygdaloid activity enhances neuronal response to acoustic stimuli
“amygdaloid activity enhances their response to acoustic stimuli”
Identify morphological characteristics of recorded neurons and determine if they are reticulospinal cells
Note: Most giant PnC neurons are reticulospinal cells with axon collaterals in reticular formation and motoneuron pools
“Anterograde tracing showed that most giant PnC neurons are reticulospinal cells. Axon collaterals and terminal arbors were found in the reticular formation as well as in cranial and spinal motoneuron pools”
This section explains what the experiment is doing, which readouts matter, what the data artifacts usually look like, and how the analysis should flow from raw capture to reported result.
Characterize physiological properties of giant PnC neurons in response to acoustic stimuli including response latencies, thresholds, frequency tuning, and habituation to understand the neuronal basis of the acoustic startle response
Objective
Characterize physiological properties of giant PnC neurons in response to acoustic stimuli including response latencies, thresholds, frequency tuning, and habituation to understand the neuronal basis of the acoustic startle response
Subjects
From paperrat • not specified • unknown • not specified • not specified
Cohort notes
From paperGiant neurons in the caudal pontine reticular nucleus (PnC) were the focus of study
Retrograde and anterograde tracing (not specified)
Intracellular recording in vivo (not specified)
Measure response latencies (not specified)
Determine firing thresholds (not specified)
Response latencies to acoustic stimuli
From papernot specified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Firing thresholds of giant PnC neurons
From papernot specified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Frequency tuning characteristics
From papernot specified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Sensitivity to stimulus rise time changes
From papernot specified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Response latencies to acoustic stimuli
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Firing thresholds of giant PnC neurons
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Frequency tuning characteristics
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Sensitivity to stimulus rise time changes
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Acquisition
Collect raw experimental outputs with enough metadata to preserve sample identity, condition, and timing.
Preprocessing / cleaning
not specified
Scoring or quantification
Quantify the primary readouts for this experiment: Response latencies to acoustic stimuli; Firing thresholds of giant PnC neurons; Frequency tuning characteristics; Sensitivity to stimulus rise time changes.
Statistical comparison
Statistical method not yet structured for this page.
Reporting output
Report representative outputs alongside summary comparisons for Response latencies to acoustic stimuli, Firing thresholds of giant PnC neurons, Frequency tuning characteristics, Sensitivity to stimulus rise time changes.
Source links and direct wording from the methods section for validation and deeper review.
Citation
K Lingenhohl et al. (1994). Giant neurons in the rat reticular formation: a sensorimotor interface in the elementary acoustic startle circuit?. Journal of Neuroscience
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Evidence Quotes
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