Application of neurosonography to experimental physiology

Glimcher, Paul W.; Ciaramitaro, Vivian; Platt, Michael L.; Bayer, H; Brown, Michael A.; Handel, Ari

doi:10.1016/s0165-0270(01)00365-x

Cited by 26 publications

(15 citation statements)

References 12 publications

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“…This method has been used to confirm the positioning of CGp in several earlier studies (e.g., McCoy et al, 2003; McCoy and Platt, 2005; Hayden et al, 2008). For details on this method, see (Glimcher et al, 2001). We found no relationship between recording position and functional properties of neurons within CGp or LIP.…”

Section: Methodsmentioning

confidence: 99%

Cognitive Control Signals in Posterior Cingulate Cortex

Hayden¹,

Smith²,

Platt³

2010

Front. Hum. Neurosci.

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Efficiently shifting between tasks is a central function of cognitive control. The role of the default network – a constellation of areas with high baseline activity that declines during task performance – in cognitive control remains poorly understood. We hypothesized that task switching demands cognitive control to shift the balance of processing toward the external world, and therefore predicted that switching between the two tasks would require suppression of activity of neurons within the posterior cingulate cortex (CGp). To test this idea, we recorded the activity of single neurons in CGp, a central node in the default network, in monkeys performing two interleaved tasks. As predicted, we found that basal levels of neuronal activity were reduced following a switch from one task to another and gradually returned to pre-switch baseline on subsequent trials. We failed to observe these effects in lateral intraparietal cortex, part of the dorsal fronto-parietal cortical attention network directly connected to CGp. These findings indicate that suppression of neuronal activity in CGp facilitates cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain.

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Section: Methodsmentioning

confidence: 99%

Cognitive Control Signals in Posterior Cingulate Cortex

Hayden¹,

Smith²,

Platt³

2010

Front. Hum. Neurosci.

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“…A 23 gauge sharpened guide tube, housing a tungsten steel electrode (2-4 M⍀ measured at 1 kHz, 0.25 mm diameter shaft; FHC, Bowdoin, ME), was used to puncture the dura. The guide tube was lowered until its tip was above or just lateral to the cingulate sulcus as predetermined using magnetic resonance imaging (3T; Siemens, Ehrlangen, Germany) in monkey B and B-mode ultrasound imaging (GE Healthcare, Little Chalfont, UK) (Glimcher et al, 2001) in monkey H. Electrophysiological signals were amplified, bandpass filtered (500 -10,000 Hz), and displayed on an oscilloscope. Individual neurons were isolated using a time-amplitude window discriminator with an adjustable Schmitt trigger (Bak Electronics, Germantown, MD), which produced transistor-transistor logic pulses corresponding to the times of single action potentials.…”

Section: Methodsmentioning

confidence: 99%

Action and Outcome Encoding in the Primate Caudate Nucleus

Lau¹,

Glimcher²

2007

J. Neurosci.

159

138

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The basal ganglia appear to have a central role in reinforcement learning. Previous experiments, focusing on activity preceding movement execution, support the idea that dorsal striatal neurons bias action selection according to the expected values of actions. However, many phasically active striatal neurons respond at a time too late to initiate or select movements. Given the data suggesting a role for the basal ganglia in reinforcement learning, postmovement activity may therefore reflect evaluative processing important for learning the values of actions. To better understand these postmovement neurons, we determined whether individual striatal neurons encode information about saccade direction, whether a reward had been received, or both. We recorded from phasically active neurons in the caudate nucleus while monkeys performed a probabilistically rewarded delayed saccade task. Many neurons exhibited peak responses after saccade execution (77 of 149) that were often tuned for the direction of the preceding saccade (61 of 77). Of those neurons responding during the reward epoch, one subset showed direction tuning for the immediately preceding saccade (43 of 60), whereas another subset responded differentially on rewarded versus unrewarded trials (35 of 60). We found that there was relatively little overlap of these properties in individual neurons. The encoding of action and outcome was performed by largely separate populations of caudate neurons that were active after movement execution. Thus, striatal neurons active primarily after a movement appear to be segregated into two distinct groups that provide complimentary information about the outcomes of actions.

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“…Glimcher [9] investigated the observability of a thin electrode inside a primate cortex in 2-D ultrasound images. From the experiments, he concludes that the ultrasound modality permits visualization of the anatomical structure together with a thin needle of diameter comparable to the ultrasound ax-ial resolution.…”

Section: B Problem Descriptionmentioning

confidence: 99%

Parallel integral projection transform for straight electrode localization in 3-D ultrasound images

Barva

Uhercik

Mari

et al. 2008

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract-In surgical practice, small metallic instruments are frequently used to perform various tasks inside the human body. We address the problem of their accurate localization in the tissue. Recent experiments using medical ultrasound have shown that this modality is suitable for real-time visualization of anatomical structures as well as the position of surgical instruments. We propose an imageprocessing algorithm that permits automatic estimation of the position of a line-segment-shaped object. This method was applied to the localization of a thin metallic electrode in biological tissue. We show that the electrode axis can be found through maximizing the Parallel Integral Projection transform that is a form of the Radon transform. To accelerate this step, hierarchical mesh-grid algorithm is implemented. Once the axis position is known, localization of the electrode tip is performed. The method was tested on simulated images, on ultrasound images of a tissue mimicking phantom containing a metallic electrode, and on real ultrasound images from breast biopsy. The results indicate that the algorithm is robust with respect to variations in electrode position and speckle noise. Localization accuracy is of the order of hundreds of micrometers and is comparable to the ultrasound system axial resolution.

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Application of neurosonography to experimental physiology

Cited by 26 publications

References 12 publications

Cognitive Control Signals in Posterior Cingulate Cortex

Cognitive Control Signals in Posterior Cingulate Cortex

Action and Outcome Encoding in the Primate Caudate Nucleus

Parallel integral projection transform for straight electrode localization in 3-D ultrasound images

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