Journal of Neurophysiology

JNP Micro Podcasts: Visual Strategy and Force-Steadiness in Older Adults

In this podcast Brittany Heintz Walters of Seattle University discusses the recently published research titled "Visual feedback and declines in attention are associated with altered visual strategy during a force-steadiness task in older adults." 

 

NEW & NOTEWORTHY This study contributes novel findings of age-related changes in visual strategy and associations with attentional deficits during hand motor tasks. Older adults used fewer saccades than young adults and with higher versus lower gain visual feedback during a force-steadiness task. A subset of older adults used an altered visual strategy when allocating attention across multiple tasks. Given that this subset demonstrated attentional deficits, the altered visual strategy could serve to indicate motor and/or cognitive impairments.

 

Article Citation:

Visual feedback and declines in attention are associated with altered visual strategy during a force-steadiness task in older adults

Brittany Heintz Walters, Wendy E. Huddleston, Kristian O’Connor, Jinsung Wang, Marie Hoeger Bement, and Kevin G. Keenan

Journal of Neurophysiology 2023 130:5, 1309-1320

JNP Micro Podcasts: Aging and Subcortical Gray Matter Volume

In this podcast Dr. Peka Christova of The Neuroimaging Research Group, Brain Sciences Center discusses the recently published Short Report titled "Changes of gray matter volumes of subcortical regions across the lifespan: a Human Connectome Project study."

NEW & NOTEWORTHY Christova et al. report mixed effects of age on subcortical grey matter volume (GMV) during lifespan (n = 2458, 5-90 yr old, 1113 male, 1345 female). Striatal and cerebellar GMVs decreased linearly with age, more steeply in males. In contrast, GMVs of the amygdala, pallidum, thalamus, ventral diencephalon, and brainstem changed in a quadratic fashion, increasing first and decreasing afterward, with males peaking earlier than females in all regions but the brainstem where they peaked at nearly the same time.

Article Citation:

Changes of gray matter volumes of subcortical regions across the lifespan: a Human Connectome Project study

Peka Christova and Apostolos P. Georgopoulos

Journal of Neurophysiology 2023 130:5, 1303-1308

JNP Micro Podcasts: Modulation of corticospinal excitability during vibration

In this episode,  Lydiane Lauzier of Université du Québec à Chicoutimi discusses the recently published article “Variation of corticospinal excitability during kinesthetic illusion induced by musculotendinous vibration.”

 

New and Noteworthy:

The modulation of corticospinal excitability when perceiving a vibration (VIB)-induced kinesthetic illusion evolves dynamically over time. This modulation might be linked to the delayed occurrence and progressive increase in strength of the illusory perception in the first seconds after VIB start. Different spinal/cortical mechanisms could be at play during VIB, depending on the tested muscle, presence/absence of an illusion, and the specific timing at which corticospinal drive is tested pre/post VIB.

 

Article Citation:

Variation of corticospinal excitability during kinesthetic illusion induced by musculotendinous vibration

Lydiane Lauzier, Marie-Pier Perron, Laurence Munger, Émilie Bouchard, Jacques Abboud, François Nougarou, and Louis-David Beaulieu

Journal of Neurophysiology 2023 130:5, 1118-1125

JNP Micro Podcasts ”Four Questions”: Robust Aggregate Code of Competing Sounds in Auditory Cortex

In this podcast, author Jian Carlo Nocon (Boston University) discusses the recently published research titled "A robust and compact population code for competing sounds in auditory cortex." 

 

NEW & NOTEWORTHY 

Little is known about how populations of neurons within cortical circuits encode sensory stimuli in the presence of competing stimuli at other spatial locations. Here, the authors investigate this problem in auditory cortex using a recently proposed information-theoretic approach. They found a small subset of neurons nearly maximizes information about target sounds in the presence of competing maskers, approaching information levels for isolated stimuli, and provides a noise-robust code for sounds in a complex auditory scene.

 

Article Citation:

A robust and compact population code for competing sounds in auditory cortex

Jian Carlo Nocon, Jake Witter, Howard Gritton, Xue Han, Conor Houghton, and Kamal Sen

Journal of Neurophysiology 2023 130:3, 775-787

JNP Micro Podcasts ”Four Questions”: Essential Tremor accentuates upper limb coherence patterns

In this podcast coauthor Daniel Free of Brigham Young University talks about the recently published article titled “Essential tremor accentuates the pattern of tremor-band coherence between upper limb muscles.”

 

NEW & NOTEWORTHY This research characterized the relationships in tremor-band activity between the 15 major superficial upper limb muscles of persons with essential tremor by quantifying the proportion of shared activity (coherence) in the tremor band and by characterizing phase differences between these muscles during various tasks. From the authors observations, they conclude that tremor enhances the coherence between muscle pairs throughout the upper limb in a pattern that reflects functional relationship between them.

 

Article Citation:

Essential tremor accentuates the pattern of tremor-band coherence between upper limb muscles

Daniel B. Free, Ian Syndergaard, Adam C. Pigg, Silvia Muceli, Johanna Thompson-Westra, Karin Mente, Carine W. Maurer, Dietrich Haubenberger, Mark Hallett, Dario Farina, and Steven K. Charles

Journal of Neurophysiology 2023 129:3, 524-540

JNP Micro Podcasts ”Four Questions”: Task-dependent negotiations of bimanual coordination

In this podcast Nick Kitchen and Jisung Yuk of Pennsylvania State University discuss the recently published manuscript “Bilateral arm movements are coordinated via task-dependent negotiations between independent and codependent control, but not by a “coupling” control policy.”

 

NEW & NOTEWORTHY Minimization of performance and control costs and efferent coupling between bilaterally homologous muscle groups have been separately hypothesized to describe patterns of bimanual coordination. Here, we address whether the mechanisms mediating independent and codependent control between limbs can be weighted for successful task performance. Using bilaterally asymmetric visuomotor gain perturbations, we show bimanual coordination can be characterized as a negotiation along a spectrum between extremes of independent and codependent control, but not efferent control coupling.

 

Article Citation:

Bilateral arm movements are coordinated via task-dependent negotiations between independent and codependent control, but not by a “coupling” control policy

Nick M. Kitchen, Jisung Yuk, Andrzej Przybyla, Robert A. Scheidt, and Robert L. Sainburg

Journal of Neurophysiology

 2023 130:3, 497-515

JNP Micro Podcasts ”Four Questions”: Otolith-ocular reflex after ototoxicity & vestibular implant

Margaret Chow and Celia Fernandez Brillet of Johns Hopkins School of Medicine discuss the recently published manuscript titled "Binocular 3-D otolith-ocular reflexes: responses of chinchillas to natural and prosthetic stimulation after ototoxic injury and vestibular implantation."

 

NEW & NOTEWORTHY Previous studies to expand the scope of prosthetic stimulation of the otolith end organs showed that selective stimulation of the utricle and saccule is possible. This article further defines those possibilities by characterizing a diseased animal model and subsequently studying its responses to electrical stimulation alone and in combination with mechanical motion. We show that we can partially restore responses to tilt and translation in animals with unilateral gentamicin ototoxic injury and contralateral surgical disruption.

 

Article Citation:

Binocular 3-D otolith-ocular reflexes: responses of chinchillas to natural and prosthetic stimulation after ototoxic injury and vestibular implantation

Margaret R. Chow, Celia Fernandez Brillet, Kristin N. Hageman, Dale C. Roberts, Andrianna I. Ayiotis, Razi M. Haque, and Charles C. Della Santina

Journal of Neurophysiology 2023 129:5, 1157-1176

JNP Micro Podcasts: Acetylcholine receptor and persistent current

In this paper first author Kelly H. Lee, and Alex Prosserman, an expert in the field discuss the recently published article titled “Cholinergic depolarization recruits a persistent Ca²⁺ current in Aplysia bag cell neurons.”

 

NEW & NOTEWORTHY Ionotropic acetylcholine receptors mediate brief synaptic communication, including in bag cell neurons of the sea snail Aplysia. However, this study demonstrates that cholinergic depolarization can open a voltage-gated persistent Ca²⁺ current, which extends the bag cell neuron response to acetylcholine. Bursting in these neuroendocrine cells results in hormone release and egg laying. Thus, this emphasizes the role of ionotropic signaling in reaching a depolarized level to engage Ca²⁺ influx and perpetuating the activity necessary for behavior.

 

Article Citation:

Cholinergic depolarization recruits a persistent Ca²⁺ current in Aplysia bag cell neurons

Kelly H. Lee, David E. Wassef, Eammon K. MacNeil, and Neil S. Magoski

Journal of Neurophysiology 2023 129:5, 1045-1060

JNP Micro Podcasts ”Four Questions”: Elijah Haynes, Jennifer Jakobi, and Jayne Kalmar

In this podcast Dr. Elijah Haynes and Dr. Jennifer Jakobi of the University of British Columbia Okanagan, and Dr. Jayne Kalmar of the Wilfrid Laurier University discuss the recently published Systematic Review titled “A systematic review of how cannabinoids affect motoneuron output.” This scoping review involved the synthesis of evidence from literature published before August 2022 about the effects of cannabinoids on quantifiable measures of motoneuron output. It contributes to understanding the effects of endocannabinoids on synaptic integration at the motoneuron and modulation of motor output.

 

Article Citation:

A systematic review of how cannabinoids affect motoneuron output

Elijah M. K. Haynes, Jayne M. Kalmar, Mathew Vis-Dunbar, Kathryn M. Crosby, Angitha Mriduraj, and Jennifer M. Jakobi

Journal of Neurophysiology

 2023 130:2, 247-263

JNP Micro Podcasts ”Four Questions”: Alexander M. Zero

In this podcast co lead author Alexander M. Zero of The University of Western Ontario discusses the recently published research titled "Motor unit firing rates in young and very old adult males during an isokinetic fatiguing task and short-term recovery in the anconeus muscle."

 

NEW & NOTEWORTHY Maximal motor unit firing rates were recorded during an isokinetic fatiguing protocol and short-term recovery in young and very old adult males. Prior studies were limited to isometric fatiguing tasks. Despite the old being ∼37% weaker and less fatigable, anconeus rates during elbow extension declined with fatigue and recovered similarly to young males. Therefore, it is unlikely that greater fatigue resistance of very old males during isokinetic contractions is related to differences in motor unit rates.

 

Article Citation:

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Motor unit firing rates in young and very old adult males during an isokinetic fatiguing task and short-term recovery in the anconeus muscle

Alexander M. Zero, Eric A. Kirk, Kevin J. Gilmore, and Charles L. Rice

Journal of Neurophysiology 2023 130:1, 179-188