David Barker
Dr. David Barker received his Ph.D. in Behavioral Neuroscience (Psychology) from Rutgers University in 2014. Dr. Barker is a systems neuroscientist whose work investigates circuits and pathways that participate in learning, motivation, and drug addiction. In particular, Dr. Barker is interested in the neural mechanisms of emotion, and how the processing of both positive and negative emotional responses to environmental stimuli drive drug-seeking behavior and perpetuate drug addiction.
Supervisors: Dr. Marisela Morales
Address: David Barker
Department of Psychology
152 Frelinghuysen Rd.
Piscataway, NJ 08854
Supervisors: Dr. Marisela Morales
Address: David Barker
Department of Psychology
152 Frelinghuysen Rd.
Piscataway, NJ 08854
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Papers by David Barker
states in the rat and have been incorporated in research paradigms
modeling important human conditions. While the majority of studies
report the quantity or rate of observed ultrasonic vocalizations, growing
evidence suggests that critical data may be contained in the acoustic
features of individual vocalizations. Thus, the goal of the present study
was to develop and validate a method for measuring acoustic parameters
of ultrasonic vocalizations that were collected using automatic
template detection. Acoustic parameters derived using this method
were found to be comparable to those collected using commercially
available software.
in studies of substance abuse. Accordingly, studies are reviewed which demonstrate roles for affective
processing in response to the presentation of drug-related cues, experimenter- and self-administered
drug, drug withdrawal, and during tests of relapse/reinstatement. The review focuses on data collected
from studies using cocaine and amphetamine, where a large body of evidence has been collected. Data
suggest that USVs capture animals’ initial positive reactions to psychostimulant administration and are capable of
identifying individual differences in affective responding. Moreover, USVs have been used to demonstrate that positive
affect becomes sensitized to psychostimulants over acute exposure before eventually exhibiting signs of tolerance. In the
drug-dependent animal, a mixture of USVs suggesting positive and negative affect is observed, illustrating mixed
responses to psychostimulants. This mixture is predominantly characterized by an initial bout of positive affect followed
by an opponent negative emotional state, mirroring affective responses observed in human addicts. During drug
withdrawal, USVs demonstrate the presence of negative affective withdrawal symptoms. Finally, it has been shown that
drug-paired cues produce a learned, positive anticipatory response during training, and that presentation of drug-paired
cues following abstinence produces both positive affect and reinstatement behavior. Thus, USVs are a useful tool for
obtaining an objective measurement of affective states in animal models of substance abuse and can increase the
information extracted from drug administration studies. USVs enable detection of subtle differences in a behavioral
response that might otherwise be missed using traditional measures.
neurobiological changes from acute to chronic drug use. However, little is known about the exact progression of changes in functional
striatal processing as drug intake persists. We sampled single-unit activity in the NAc and DLS throughout 24 daily sessions
of chronic long-access cocaine self-administration, and longitudinally tracked firing rates (FR) specifically during the operant
response, an upward vertical head movement. A total of 103 neurons were held longitudinally and immunohistochemically localised
to either NAc Medial Shell (n = 29), NAc Core (n = 30), or DLS (n = 54). We modeled changes representative of each category
as a whole. Results demonstrated that FRs of DLS Head Movement neurons were significantly increased relative to
baseline during all sessions, while FRs of DLS Uncategorised neurons were significantly reduced relative to baseline during all
sessions. NAc Shell neurons’ FRs were also significantly decreased relative to baseline during all sessions while FRs of NAc
Core neurons were reduced relative to baseline only during training days 1–18 but were not significantly reduced on the remaining
sessions (19–24). The data suggest that all striatal subregions show changes in FR during the operant response relative to baseline,
but longitudinal changes in response firing patterns were observed only in the NAc Core, suggesting that this region is particularly
susceptible to plastic changes induced by abused drugs.
been studied extensively and is relatively well understood. On the contrary, the functionality
and physiology of the dorsolateral striatum (DLS), the immediate downstream region
of M1 and S1 and a critical link in the motor circuit, still requires intensive investigation.
In the current study, spike trains of individual DLS neurons were reconstructed using a
Linear-Nonlinear-Poisson model with features from two modalities: (1) the head position
modality, which contains information regarding head movement and proprioception of the
animal’s head; (2) the spike history modality, which contains information regarding the
intrinsic physiological properties of the neuron. For the majority of the neurons examined,
viable reconstruction accuracy was achieved when the neural activity was modeled with
either feature modality or the two feature modalities combined. Subpopulations of neurons
were also identified that had better reconstruction accuracy when modeled with features
from single modalities. This study demonstrates the feasibility of spike train reconstruction
in DLS neurons and provides insights into the physiology of DLS neurons.
Ultrasonic vocalizations (USVs) have been utilized to infer animals' affective states in multiple research paradigms including animal models of drug abuse, depression, fear or anxiety disorders, Parkinson's disease, and in studying neural substrates of reward processing. Currently, the analysis of USV data is performed manually, and thus time consuming.
NEW METHOD:
The goal of the present study was to develop a method for automated USV recognition using a 'template detection' procedure for vocalizations in the 50-kHz range (35-80kHz). The detector is designed to run within XBAT, a MATLAB graphical user interface and extensible bioacoustics tool developed at Cornell University.
RESULTS:
Results show that this method is capable of detecting >90% of emitted USVs and that time spent collecting data by experimenters is greatly reduced.
COMPARISON WITH EXISTING METHODS:
Currently, no viable and publicly available methods exist for the automated detection of USVs. The present method, in combination with the XBAT environment is ideal for the USV community as it allows others to 1) detect USVs within a user-friendly environment, 2) make improvements to the detector and disseminate and 3) develop new tools for analysis within the MATLAB environment.
CONCLUSIONS:
The present detector provides an open-source, accurate method for the detection of 50-kHz USVs. Ongoing research will extend the current method for use in the 22-kHz frequency range of ultrasonic vocalizations. Moreover, collaborative efforts among USV researchers might enhance the capabilities of the current detector via changes to the templates and the development of new programs for analysis.
states in the rat and have been incorporated in research paradigms
modeling important human conditions. While the majority of studies
report the quantity or rate of observed ultrasonic vocalizations, growing
evidence suggests that critical data may be contained in the acoustic
features of individual vocalizations. Thus, the goal of the present study
was to develop and validate a method for measuring acoustic parameters
of ultrasonic vocalizations that were collected using automatic
template detection. Acoustic parameters derived using this method
were found to be comparable to those collected using commercially
available software.
in studies of substance abuse. Accordingly, studies are reviewed which demonstrate roles for affective
processing in response to the presentation of drug-related cues, experimenter- and self-administered
drug, drug withdrawal, and during tests of relapse/reinstatement. The review focuses on data collected
from studies using cocaine and amphetamine, where a large body of evidence has been collected. Data
suggest that USVs capture animals’ initial positive reactions to psychostimulant administration and are capable of
identifying individual differences in affective responding. Moreover, USVs have been used to demonstrate that positive
affect becomes sensitized to psychostimulants over acute exposure before eventually exhibiting signs of tolerance. In the
drug-dependent animal, a mixture of USVs suggesting positive and negative affect is observed, illustrating mixed
responses to psychostimulants. This mixture is predominantly characterized by an initial bout of positive affect followed
by an opponent negative emotional state, mirroring affective responses observed in human addicts. During drug
withdrawal, USVs demonstrate the presence of negative affective withdrawal symptoms. Finally, it has been shown that
drug-paired cues produce a learned, positive anticipatory response during training, and that presentation of drug-paired
cues following abstinence produces both positive affect and reinstatement behavior. Thus, USVs are a useful tool for
obtaining an objective measurement of affective states in animal models of substance abuse and can increase the
information extracted from drug administration studies. USVs enable detection of subtle differences in a behavioral
response that might otherwise be missed using traditional measures.
neurobiological changes from acute to chronic drug use. However, little is known about the exact progression of changes in functional
striatal processing as drug intake persists. We sampled single-unit activity in the NAc and DLS throughout 24 daily sessions
of chronic long-access cocaine self-administration, and longitudinally tracked firing rates (FR) specifically during the operant
response, an upward vertical head movement. A total of 103 neurons were held longitudinally and immunohistochemically localised
to either NAc Medial Shell (n = 29), NAc Core (n = 30), or DLS (n = 54). We modeled changes representative of each category
as a whole. Results demonstrated that FRs of DLS Head Movement neurons were significantly increased relative to
baseline during all sessions, while FRs of DLS Uncategorised neurons were significantly reduced relative to baseline during all
sessions. NAc Shell neurons’ FRs were also significantly decreased relative to baseline during all sessions while FRs of NAc
Core neurons were reduced relative to baseline only during training days 1–18 but were not significantly reduced on the remaining
sessions (19–24). The data suggest that all striatal subregions show changes in FR during the operant response relative to baseline,
but longitudinal changes in response firing patterns were observed only in the NAc Core, suggesting that this region is particularly
susceptible to plastic changes induced by abused drugs.
been studied extensively and is relatively well understood. On the contrary, the functionality
and physiology of the dorsolateral striatum (DLS), the immediate downstream region
of M1 and S1 and a critical link in the motor circuit, still requires intensive investigation.
In the current study, spike trains of individual DLS neurons were reconstructed using a
Linear-Nonlinear-Poisson model with features from two modalities: (1) the head position
modality, which contains information regarding head movement and proprioception of the
animal’s head; (2) the spike history modality, which contains information regarding the
intrinsic physiological properties of the neuron. For the majority of the neurons examined,
viable reconstruction accuracy was achieved when the neural activity was modeled with
either feature modality or the two feature modalities combined. Subpopulations of neurons
were also identified that had better reconstruction accuracy when modeled with features
from single modalities. This study demonstrates the feasibility of spike train reconstruction
in DLS neurons and provides insights into the physiology of DLS neurons.
Ultrasonic vocalizations (USVs) have been utilized to infer animals' affective states in multiple research paradigms including animal models of drug abuse, depression, fear or anxiety disorders, Parkinson's disease, and in studying neural substrates of reward processing. Currently, the analysis of USV data is performed manually, and thus time consuming.
NEW METHOD:
The goal of the present study was to develop a method for automated USV recognition using a 'template detection' procedure for vocalizations in the 50-kHz range (35-80kHz). The detector is designed to run within XBAT, a MATLAB graphical user interface and extensible bioacoustics tool developed at Cornell University.
RESULTS:
Results show that this method is capable of detecting >90% of emitted USVs and that time spent collecting data by experimenters is greatly reduced.
COMPARISON WITH EXISTING METHODS:
Currently, no viable and publicly available methods exist for the automated detection of USVs. The present method, in combination with the XBAT environment is ideal for the USV community as it allows others to 1) detect USVs within a user-friendly environment, 2) make improvements to the detector and disseminate and 3) develop new tools for analysis within the MATLAB environment.
CONCLUSIONS:
The present detector provides an open-source, accurate method for the detection of 50-kHz USVs. Ongoing research will extend the current method for use in the 22-kHz frequency range of ultrasonic vocalizations. Moreover, collaborative efforts among USV researchers might enhance the capabilities of the current detector via changes to the templates and the development of new programs for analysis.