scholarly journals It’s not you, it’s me: Corollary discharge in precerebellar nuclei of sleeping infant rats

2018 ◽  
Author(s):  
Didhiti Mukherjee ◽  
Greta Sokoloff ◽  
Mark S. Blumberg
Keyword(s):  
Neural Activity ◽  
Inferior Olive ◽  
Corollary Discharge ◽  
Reticular Nucleus ◽  
Infant Rats ◽  
Precerebellar Nuclei ◽  
Somatosensory Input ◽  
Slow Potassium ◽  
Old Rats ◽  
Developing Cerebellum

AbstractIn week-old rats, somatosensory input arises predominantly from stimuli in the external environment or from sensory feedback associated with myoclonic twitches during active (REM) sleep. A previous study of neural activity in cerebellar cortex raised the possibility that the brainstem motor structures that produce twitches also send copies of motor commands (or corollary discharge, CD) to the cerebellum. Here, by recording from two precerebellar nuclei—the inferior olive and lateral reticular nucleus—we demonstrate that CD does indeed accompany the production of twitches. Within both structures, the CD signal comprises a surprisingly sharp activity peak within 10 ms of twitch onset. In the inferior olive, this sharp peak is attributable to the opening of slow potassium channels. We conclude that a diversity of neural activity is conveyed to the developing cerebellum preferentially during sleep-related twitching, enabling cerebellar processing of convergent input from CD and reafferent signals.

scholarly journals Corollary discharge in precerebellar nuclei of sleeping infant rats

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Didhiti Mukherjee ◽  
Greta Sokoloff ◽  
Mark S Blumberg
Keyword(s):  
Corollary Discharge ◽  
Reticular Nucleus ◽  
Sk Channels ◽  
Precerebellar Nuclei ◽  
Somatosensory Input ◽  
Slow Potassium ◽  
Old Rats ◽  
Production Areas ◽  
External Stimuli ◽  
Developing Cerebellum

In week-old rats, somatosensory input arises predominantly from external stimuli or from sensory feedback (reafference) associated with myoclonic twitches during active sleep. A previous study suggested that the brainstem motor structures that produce twitches also send motor copies (or corollary discharge, CD) to the cerebellum. We tested this possibility by recording from two precerebellar nuclei—the inferior olive (IO) and lateral reticular nucleus (LRN). In most IO and LRN neurons, twitch-related activity peaked sharply around twitch onset, consistent with CD. Next, we identified twitch-production areas in the midbrain that project independently to the IO and LRN. Finally, we blocked calcium-activated slow potassium (SK) channels in the IO to explain how broadly tuned brainstem motor signals can be transformed into precise CD signals. We conclude that the precerebellar nuclei convey a diversity of sleep-related neural activity to the developing cerebellum to enable processing of convergent input from CD and reafferent signals.

scholarly journals Influence of l-type slow calcium channels blockers on cardiac, respiratory and motor activity at the intact and poisoned by physostigmine (eserine) of rats during the early ontogeny

2019 ◽  
Vol 17 (3) ◽  
pp. 39-49
Author(s):  
Sergey V. Kuznetsov ◽  
Nataliya N. Kuznetsova ◽  
Polina A. Gaydukova
Keyword(s):  
Calcium Channels ◽  
Motor Activity ◽  
Respiration Rate ◽  
Heart Rhythm ◽  
Early Ontogeny ◽  
Ache Inhibitor ◽  
Channel Blockers ◽  
Infant Rats ◽  
Old Rats ◽  
Calcium Channels Blockers

The effects of calcium-channel blockers (CCBs) (verapamil, nifedipine) on heart rate, respiration rate and motor activity were studied in 3-30-day-old rats. The role of calcium channels in development of disturbances of a heart and respiratory rhythms after introduction to newborn rats of acetylcholinesterase (AChE) inhibitor of physostigmine was revealed. Parameters of functional activity of heart, respiratory and somatomotor systems in case of blockade of calcium channels were studied also under conditions of the activation of cholinoceptive structures caused by an injection to infant rats of AChE inhibitor after premedication by CCBs. It is shown that use of calcium channels blockers leads to development of bradycardia, and verapamil causes more expressed disturbance of a heart rhythm in rats of younger age, while blockade of dihydropyridinic receptors by nifedipine has no ontogenetic specifics. Similar ontogenetic dynamics concerns also reaction of respiratory system. Verapamil have a detrimental effect on respiration, up to a stop, in 3-7-day-old and to a lesser extent in 16-30-day-old infant rats. Nifedipine slightly reduces a respiration rate at younger infant rats, but raises it at the mature rats. The nifedipine injection more in comparison with verapamil changes the level and a pattern of motor activity. Preliminary blockade of calcium channels does not render significant change of reaction at the subsequent introduction of physostigmin.

scholarly journals tACS entrains neural activity while somatosensory input is blocked

2019 ◽  
Author(s):  
Pedro G. Vieira ◽  
Matthew R. Krause ◽  
Christopher C. Pack
Keyword(s):  
Electric Fields ◽  
Neural Activity ◽  
Alternative Hypothesis ◽  
Brain Regions ◽  
Nerve Fibers ◽  
Great Promise ◽  
Direct Stimulation ◽  
Topical Anesthetic ◽  
Somatosensory Stimulation ◽  
Somatosensory Input

AbstractTranscranial alternating current stimulation (tACS) modulates brain activity by passing electrical current through electrodes that are attached to the scalp. Because it is safe and non-invasive, it holds great promise as a tool for basic research and clinical treatment. However, little is known about how tACS ultimately influences neural activity. One hypothesis is that tACS affects neural responses directly, by producing electrical fields that interact with the brain’s endogenous electrical activity. Since the shape and location of these electric fields can be controlled, stimulation could be targeted at brain regions associated with particular behaviors or symptoms. However, an alternative hypothesis is that tACS affects neural activity indirectly, via peripheral sensory afferents. In particular, it has often been hypothesized that tACS acts on nerve fibers in the skin, which in turn provide rhythmic input to central neurons. In this case, there would be little possibility of targeted brain stimulation, as the regions modulated by tACS would depend entirely on the somatosensory pathways originating in the skin around the stimulating electrodes. Here, we directly test these competing hypotheses by recording single-unit activity in the hippocampus and visual cortex of monkeys receiving tACS. We find that tACS entrains neuronal activity in both regions, so that cells fire synchronously with the stimulation. Blocking somatosensory input with a topical anesthetic does not significantly alter these neural entrainment effects. These data are therefore consistent with the direct stimulation hypothesis and suggest that peripheral somatosensory stimulation is not required for tACS to entrain neurons.

Further evidence that BAT thermogenesis modulates cardiac rate in infant rats

1998 ◽  
Vol 274 (6) ◽  
pp. R1712-R1717 ◽  
Author(s):  
Greta Sokoloff ◽  
Robert F. Kirby ◽  
Mark S. Blumberg
Keyword(s):  
Adipose Tissue ◽  
Protective Role ◽  
Cardiac Rate ◽  
Warm Environment ◽  
Infant Rats ◽  
Brown Adipose ◽  
Warm Blood ◽  
Old Rats ◽  
Focal Cooling ◽  
Interscapular Region

Previous research in infant rats suggested that brown adipose tissue (BAT), by providing warm blood to the heart during moderate cold exposure, protects cardiac rate. This protective role for BAT thermogenesis was examined further in the present study. In experiment 1, 1-wk-old rats in a warm environment were pretreated with saline or chlorisondamine (a ganglionic blocker), and then BAT thermogenesis was stimulated by injection with the β3-agonist CL-316243. In experiment 2, pups were pretreated with chlorisondamine and injected with CL-316243, and after BAT thermogenesis was stimulated the interscapular region of the pups was cooled externally with a thermode. In both experiments, cardiac rate, oxygen consumption, and physiological temperatures were monitored. Activation of BAT thermogenesis substantially increased cardiac rate in saline- and chlorisondamine-treated pups, and focal cooling of the interscapular region was sufficient to lower cardiac rate. The results of these studies support the hypothesis that BAT thermogenesis contributes directly to the modulation of cardiac rate.

scholarly journals Prefrontal gating of sensory input differentiates cognitively impaired and unimpaired aging adults with HIV

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Rachel K Spooner ◽  
Alex I Wiesman ◽  
Jennifer O’Neill ◽  
Mikki D Schantell ◽  
Howard S Fox ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Neural Activity ◽  
Cognitively Impaired ◽  
Neurocognitive Disorder ◽  
Spontaneous Neural Activity ◽  
Somatosensory Input ◽  
Hiv Associated Neurocognitive Disorder ◽  
Aging Adults ◽  
The Impact ◽  
Prefrontal Cortices

Abstract Despite effective therapies that have extended the life expectancy of persons living with HIV, 35–70% of these adults still develop some form of cognitive impairment, and with a growing population of aging adults with HIV, the prevalence of these cognitive deficits is likely to increase. The mechanisms underlying these HIV-associated neurocognitive disorders remain poorly understood but are often accelerated by the aging process and accompanied by disturbances in sensory processing, which may contribute to the observed cognitive decline. The goal of the current study was to identify the impact of aging on HIV-related alterations in inhibitory processing and determine whether such alterations are related to cognitive impairment in neuroHIV. We used magnetoencephalographic imaging, advanced time series analysis methods, and a paired-pulse stimulation paradigm to interrogate inhibitory processing in 87 HIV-infected aging adults and 92 demographically matched uninfected controls (22–72 years old). Whole-brain maps linking age and neural indices were computed for each group and compared via Fisher’s Z transformations. Peak voxel time-series data were also extracted from the resulting images to quantify the dynamics of spontaneous neural activity preceding stimulation onset in each group. Whole-brain analyses using the somatosensory gating index, a metric of inhibitory processing and age distinguished impaired adults with HIV from unimpaired HIV-infected adults and controls. Briefly, younger cognitively impaired adults with HIV strongly utilized the prefrontal cortices to gate somatosensory input, and the role of this region in gating was uniquely and significantly modulated by aging only in impaired adults with HIV. Spontaneous neural activity preceding stimulus onset was also significantly elevated in the prefrontal cortices of those with HIV-associated neurocognitive disorder, and this elevation was significantly related to the CD4 nadir across both HIV-infected groups. This is the first study to examine the impact of aging on inhibitory processing in HIV-infected adults with and without cognitive impairment. Our findings suggest that young adults with HIV-associated neurocognitive disorder utilize the prefrontal cortices to gate (i.e. suppress) redundant somatosensory input, and that this capacity uniquely diminishes with advancing age in impaired adults with HIV.

Age-related changes of growth hormone secretory mechanisms in the rat pituitary gland

1991 ◽  
Vol 131 (2) ◽  
pp. 251-257 ◽  
Author(s):  
M. Parenti ◽  
D. Cocchi ◽  
G. Ceresoli ◽  
C. Marcozzi ◽  
E. E. Müller
Keyword(s):  
Growth Hormone ◽  
Male Rats ◽  
Lower Percentage ◽  
Aged Rats ◽  
Adult Rats ◽  
Infant Rats ◽  
Age Related ◽  
Rat Pituitary ◽  
Old Rats ◽  
Stimulation Of

ABSTRACT The mechanisms underlying the age-related decrease and increase in somatotroph responsiveness to growth hormone-releasing factor (GHRF) and somatostatin respectively were studied in rat pituitary membranes in vitro. Basal adenylate cyclase (AC) activity was similar in pituitary membranes from rats of 8 days (either sex) and male rats of 3 months, but it was almost threefold higher in membranes from male rats of 21–23 months. GHRF induced a lower percentage stimulation of AC activity in membranes from infant and old than adult rats. Somatostatin inhibited stimulation of AC induced by forskolin more effectively in membranes from adult than infant and old rats. In parallel experiments, since the tissue we used is formed by a mixed population of pituitary cells, we evaluated, for comparison, the effect on AC of neurohormones, i.e. vasoactive intestinal polypeptide (VIP) and dopamine which act primarily on lactotrophs. VIP induced a lower fold-stimulation of AC activity in membranes from infant and old than adult rats. Dopamine inhibited forskolin-induced stimulation of AC in the following rank order of magnitude: old, adult and infant rats, and was also more effective in inhibiting basal AC activity in old than in adult rats. The stimulatory and inhibitory G proteins (Gs and Gi) coupled to AC were measured indirectly by evaluating stimulatory and inhibitory effects of different concentrations of GTP on AC. GTP, at stimulatory concentrations, increased AC activity in membranes from infant and adult rats similarly whereas its effect was significantly greater in membranes from old rats. Conversely, GTP, at inhibitory concentrations, decreased AC activity similarly in membranes from adult and infant rats, whereas in old rats inhibition was apparent at more than a tenfold lower concentration of GTP. These data suggest (1) that the greater somatotroph sensitivity to GHRF in terms of GH secretion of the early postnatal period is not due to supersensitive GHRF receptors but rather may be accounted for, at least partially, by the low function of somatostatinergic receptors; (2) that the inability of GHRF to stimulate GH release in aged rats probably results from an uncoupling between the GHRF receptor and the G protein; and (3) that in aged rats the decreased ability of somatostatin to inhibit AC activity, in spite of the high Gi activity, results from a reduced number of somatotroph cells and, hence, receptors. Journal of Endocrinology (1991) 131, 251–257

scholarly journals Twitch-related and rhythmic activation of the developing cerebellar cortex

2015 ◽  
Vol 114 (3) ◽  
pp. 1746-1756 ◽  
Author(s):  
Greta Sokoloff ◽  
Alan M. Plumeau ◽  
Didhiti Mukherjee ◽  
Mark S. Blumberg
Keyword(s):  
Mossy Fiber ◽  
Cell Activity ◽  
Emg Activity ◽  
Spontaneous Movements ◽  
Innervation Patterns ◽  
Old Rats ◽  
Developing Cerebellum ◽  
The Relationship ◽  
Activity Dependent ◽  
Complex And Simple Spikes

The cerebellum is a critical sensorimotor structure that exhibits protracted postnatal development in mammals. Many aspects of cerebellar circuit development are activity dependent, but little is known about the nature and sources of the activity. Based on previous findings in 6-day-old rats, we proposed that myoclonic twitches, the spontaneous movements that occur exclusively during active sleep (AS), provide generalized as well as topographically precise activity to the developing cerebellum. Taking advantage of known stages of cerebellar cortical development, we examined the relationship between Purkinje cell activity (including complex and simple spikes), nuchal and hindlimb EMG activity, and behavioral state in unanesthetized 4-, 8-, and 12-day-old rats. AS-dependent increases in complex and simple spike activity peaked at 8 days of age, with 60% of units exhibiting significantly more activity during AS than wakefulness. Also, at all three ages, approximately one-third of complex and simple spikes significantly increased their activity within 100 ms of twitches in one of the two muscles from which we recorded. Finally, we observed rhythmicity of complex and simple spikes that was especially prominent at 8 days of age and was greatly diminished by 12 days of age, likely due to developmental changes in climbing fiber and mossy fiber innervation patterns. All together, these results indicate that the neurophysiological activity of the developing cerebellum can be used to make inferences about changes in its microcircuitry. They also support the hypothesis that sleep-related twitches are a prominent source of discrete climbing and mossy fiber activity that could contribute to the activity-dependent development of this critical sensorimotor structure.

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