bluuebunny/crossref_metadata_2025 huggingface dataset:
Response Patterns and Force Relations of Monkey Spinal Interneurons During Active Wrist Movement
Authors: Maier Marc A. , Perlmutter Steve I. , Fetz Eberhard E.
Published: December 2017

Maier, Marc A., Steve I. Perlmutter, and Eberhard E. Fetz. Response patterns and force relations of monkey spinal interneurons during active wrist movement. J. Neurophysiol. 80: 2495–2513, 1998. The activity of C6–T1 spinal cord neurons was recorded in three macaques while they generated isometric wrist flexion and extension torques in visually guided step-tracking tasks. Electromyographic activity (EMG) was recorded in ≤12 independent forearm muscles. Spike-triggered averages (STAs) of rectified and unrectified EMG were used to classify neurons into four groups. Motoneurons (MNs) had a clear postspike motor unit signature in the unrectified STA of one muscle. Premotor interneurons (PreM-INs) had postspike effects in at least one muscle, with onset latencies of ≥3.5 ms from the trigger. Synchrony interneurons (Sy-INs) were non-PreM-Ins that had spike-related features with latencies <3.5 ms in at least one muscle. Unidentified interneurons (U-INs) showed no features in any of the STAs. A total of 572 task-related spinal neurons were studied; 29 cells were MNs, 97 PreM-INs, 32 Sy-INs, and 414 U-INs. MNs were activated predominantly in a tonic fashion during the ramp-and-hold torques and were active in one direction only. The most common response pattern for interneurons, irrespective of their class, was phasic-tonic activity, followed by purely tonic and purely phasic activity. Most interneurons (77%) were bidirectionally active in both flexion and extension. For all classes of interneurons, units with phasic response components tended to be activated first, before torque onset, followed by tonic units. The onset times of PreM-INs relative to onsets of their target muscles were distributed broadly, with a mean of −25 ± 128 (SD) ms. For most neurons with tonic response components (all MNs, 71% of PreM-INs, 67% of Sy-INs, and 84% of U-INs), activity during the hold period was correlated significantly with the magnitude of static torque exerted by the monkey. The rate-torque regressions generally had positive slopes with higher mean slopes for extension than for flexion. The phasic response components were correlated significantly with rate of change of torque for a smaller percentage of tested PreM-Ins (50%), Sy-INs (83%), and U-INs (77%). In contrast to other premotor neurons [corticomotoneuronal (CM), rubromotoneuronal (RM), and dorsal root ganglion (DRG) afferents] previously characterized under similar conditions, a larger proportion of the spinal PreM-INs were activated after onset of their target muscles, probably reflecting a larger proportion of PreM-INs driven by peripheral input. The rate-torque slopes of PreM-INs tended to be less steep than those of CM and RM cells. Unlike the CM and DRG PreM afferents, which were activated unidirectionally, most spinal PreM-INs showed bidirectional activity, like RM cells.
Cortical Correlate of the Piper Rhythm in Humans
Authors: Brown Peter , Salenius Stephan , Rothwell John C. , Hari Riitta
Published: December 2017

Brown, Peter, Stephan Salenius, John C. Rothwell, and Riitta Hari. Cortical correlate of the Piper rhythm in humans. J. Neurophysiol. 80: 2911–2917, 1998. The electromyogram (EMG) of healthy humans demonstrates a tendency to rhythmic oscillations at around 40 Hz (the Piper rhythm) during strong voluntary contraction. Why motor units should discharge synchronously locked to such a high-frequency is unclear. We recorded whole scalp magnetoencephalographic (MEG) signals simultaneously with surface EMG from 10 healthy subjects. In eight subjects, coherence and time domain analyses demonstrated correspondence between the MEG signal, originating near or in the hand region of the motor cortex, and the 35- to 60-Hz EMG recorded during repeated maximal isometric contractions of the contralateral forearm extensor muscles. Three of these subjects also showed similar coherence during isometric contractions of moderate strength and slow extension movements of the wrist. In addition, coherence and time domain analyses demonstrated correspondence between the MEG signals originating near or in the foot area of the motor cortex and EMG recorded during repeated maximal isometric contractions of the contralateral tibialis anterior muscle in the 30- to 60-Hz range. Most important, the frequency at the peak of the coherence spectrum differed between forearm and leg by as much as 10 Hz in the same subject. In contrast, the peak of the coherence spectrum occurred during sustained weak contraction in the 20- to 30-Hz range similarly for both forearm and foot. The lag between EMG and MEG activity in the leg was ∼15 ms greater than that seen in the forearm, an interval appropriate for conduction in fast pyramidal pathways. It is concluded that the Piper rhythm in muscle may be driven by a comparable oscillatory activity in the contralateral motor cortex. This cortical rhythmicity can be picked up in several types of movement and seems distinct from the 20- to 30-Hz rhythmicity recorded during weak sustained contractions.
Recovery of fMRI Activation in Motion Area MT Following Storage of the Motion Aftereffect
Authors: Culham Jody C. , Dukelow Sean P. , Vilis Tutis , Hassard Frank A. , Gati Joseph S. , Menon Ravi S. , Goodale Melvyn A.
Published: December 2017

Culham, Jody C., Sean P. Dukelow, Tutis Vilis, Frank A. Hassard, Joseph S. Gati, Ravi S. Menon, and Melvyn A. Goodale. Recovery of fMRI activation in motion area MT following storage of the motion aftereffect. J. Neurophysiol. 81: 388–393, 1999. We used functional magnetic resonance imaging (fMRI) during storage of the motion aftereffect (MAE) to examine the relationship between motion perception and neural activity in the human cortical motion complex MT+ (including area MT and adjacent motion-selective cortex). MT+ responds not only to physical motion but also to illusory motion, as in the MAE when subjects who have adapted to continuous motion report that a subsequent stationary test stimulus appears to move in the opposite direction. In the phenomenon of storage, the total decay time of the MAE is extended by inserting a dark period between adaptation and test phases. That is, when the static test pattern is presented after a storage period equal in duration to the normal MAE, the illusory motion reappears for almost as long as the original effect despite the delay. We examined fMRI activation in MT+ during and after storage. Seven subjects viewed continuous motion, followed either by an undelayed stationary test (immediate MAE) or by a completely dark storage interval preceding the test (stored MAE). Like the perceptual effect, activity in MT+ dropped during the storage interval then rebounded to reach a level much higher than after the same delay without storage. Although MT+ activity was slightly enhanced during the storage period following adaptation to continuous motion (compared with a control sequence in which the adaptation grating oscillated and no MAE was perceived), this enhancement was much less than that observed during the perceptual phenomenon. These results indicate that following adaptation, activity in MT+ is pronounced only with the presentation of an appropriate visual stimulus, during which the MAE is perceived.
Nitric Oxide Mediates the Central Sensitization of Primate Spinothalamic Tract Neurons
Authors: Lin Qing , Palec̆ek Jiri , Palec̆ková Veronika , Peng Yuan Bo , Wu Jing , Cui Minglei , Willis William D.
Published: December 2017

Nitric oxide mediates the central sensitization of primate spinothalamic tract neurons. Nitric oxide (NO) has been proposed to contribute to the development of hyperalgesia by activating the NO/guanosine 3′,5′-cyclic monophosphate (cGMP) signal transduction pathway in the spinal cord. We have examined the effects of NO on the responses of primate spinothalamic tract (STT) neurons to peripheral cutaneous stimuli and on the sensitization of STT cells following intradermal injection of capsaicin. The NO level within the spinal dorsal horn was increased by microdialysis of a NO donor, 3-morpholinosydnonimine (SIN-1). SIN-1 enhanced the responses of STT cells to both weak and strong mechanical stimulation of the skin. This effect was preferentially on deep wide dynamic range STT neurons. The responses of none of the neurons tested to noxious heat stimuli were significantly changed when SIN-1 was administered. Intradermal injection of capsaicin increased dramatically the content of NO metabolites, [Formula: see text] within the dorsal horn. This effect was attenuated by pretreatment of the spinal cord with a nitric oxide synthase (NOS) inhibitor, NG-nitro-l-arginine methyl ester (l-NAME). Sensitization of STT cells induced by intradermal injection of capsaicin was also prevented by pretreatment of the dorsal horn with the NOS inhibitors, l-NAME or 7-nitroindazole. Blockade of NOS did not significantly affect the responses of STT cells to peripheral stimulation in the absence of capsaicin injection. The data suggest that NO contributes to the development and maintenance of central sensitization of STT cells and the resultant mechanical hyperalgesia and allodynia after peripheral tissue damage or inflammation. NO seems to play little role in signaling peripheral stimuli under physiological conditions.
Active Signaling of Leg Loading and Unloading in the Cockroach
Authors: Ridgel Angela L. , Frazier S. Faith , Dicaprio Ralph A. , Zill Sasha N.
Published: December 2017

Active signaling of leg loading and unloading in the cockroach. The ability to detect changes in load is important for effective use of a leg in posture and locomotion. While a number of limb receptors have been shown to encode increases in load, few afferents have been demonstrated to signal leg unloading, which occurs cyclically during walking and is indicative of slipping or perturbations. We applied mechanical forces to the cockroach leg at controlled rates and recorded activities of the tibial group of campaniform sensilla, mechanoreceptors that encode forces through the strains they produce in the exoskeleton. Discrete responses were elicited from the group to decreasing as well as increasing levels of leg loading. Discharges of individual afferents depended on the direction of force application, and unit responses were correlated morphologically with the orientation of the receptor’s cuticular cap. No units responded bidirectionally. Although discharges to decreasing levels of load were phasic, we found that these bursts could effectively encode the rate of force decreases. These discharges may be important in indicating leg unloading in the step cycle during walking and could rapidly signal force decreases during perturbations or loss of ground support.
Functional Expression of Exogenous Proteins in Mammalian Sensory Hair Cells Infected With Adenoviral Vectors
Authors: Holt Jeffrey R. , Johns David C. , Wang Sam , Chen Zheng-Yi , Dunn Robert J. , Marban Eduardo , Corey David P.
Published: December 2017

Functional expression of exogenous proteins in mammalian sensory hair cells infected with adenoviral vectors. To understand the function of specific proteins in sensory hair cells, it is necessary to add or inactivate those proteins in a system where their physiological effects can be studied. Unfortunately, the usefulness of heterologous expression systems for the study of many hair cell proteins is limited by the inherent difficulty of reconstituting the hair cell’s exquisite cytoarchitecture. Expression of exogenous proteins within hair cells themselves may provide an alternative approach. Because recombinant viruses were efficient vectors for gene delivery in other systems, we screened three viral vectors for their ability to express exogenous genes in hair cells of organotypic cultures from mouse auditory and vestibular organs. We observed no expression of the genes for β-galactosidase or green fluorescent protein (GFP) with either herpes simplex virus or adeno-associated virus. On the other hand, we found robust expression of GFP in hair cells exposed to a recombinant, replication-deficient adenovirus that carried the gene for GFP driven by a cytomegalovirus promoter. Titers of 4 × 107pfu/ml were sufficient for expression in 50% of the ∼1,000 hair cells in the utricular epithelium; < 1% of the nonhair cells in the epithelium were GFP positive. Expression of GFP was evident as early as 12 h postinfection, was maximal at 4 days, and continued for at least 10 days. Over the first 36 h there was no evidence of toxicity. We recorded normal voltage-dependent and transduction currents from infected cells identified by GFP fluorescence. At longer times hair bundle integrity was compromised despite a cell body that appeared healthy. To assess the ability of adenovirus-mediated gene transfer to alter hair cell function we introduced the gene for the ion channel Kir2.1. We used an adenovirus vector encoding Kir2.1 fused to GFP under the control of an ecdysone promoter. Unlike the diffuse distribution within the cell body we observed with GFP, the ion channel–GFP fusion showed a pattern of fluorescence that was restricted to the cell membrane and a few extranuclear punctate regions. Patch-clamp recordings confirmed the expression of an inward rectifier with a conductance of 43 nS, over an order of magnitude larger than the endogenous inward rectifier. The zero-current potential in infected cells was shifted by −17 mV. These results demonstrate an efficient method for gene transfer into both vestibular and auditory hair cells in culture, which can be used to study the effects of gene products on hair cell function.
Isodirectional Tuning of Adjacent Interneurons and Pyramidal Cells During Working Memory: Evidence for Microcolumnar Organization in PFC
Authors: Rao Srinivas G. , Williams Graham V. , Goldman-Rakic Patricia S.
Published: December 2017

Isodirectional tuning of adjacent interneurons and pyramidal cells during working memory: evidence for microcolumnar organization in PFC. Studies on the cellular mechanisms of working memory demonstrated that neurons in dorsolateral prefrontal cortex (dPFC) exhibit directionally tuned activity during an oculomotor delayed response. To determine the particular contributions of pyramidal cells and interneurons to spatial tuning in dPFC, we examined both individually and in pairs the tuning properties of regular-spiking (RS) and fast-spiking (FS) units that represent putative pyramidal cells and interneurons, respectively. Our main finding is that FS units possess spatially tuned sensory, motor, and delay activity (i.e., “memory fields”) similar to those found in RS units. Furthermore, when recorded simultaneously at the same site, the majority of neighboring neurons, whether FS or RS, displayed isodirectional tuning, i.e., they shared very similar tuning angles for the sensory and delay phases of the task. As the trial entered the response phase of the task, many FS units shifted their direction of tuning and became cross-directional to adjacent RS units by the end of the trial. These results establish that a large part of inhibition in prefrontal cortex is spatially oriented rather than being untuned and simply regulating the threshold response of pyramidal cell output. Moreover, the isodirectional tuning between adjacent neurons supports a functional microcolumnar organization in dPFC for spatial memory fields similar to that found in other areas of cortex for sensory receptive fields.
Electrophysiological Recordings and Calcium Measurements in Striatal Large Aspiny Interneurons in Response to Combined O2/Glucose Deprivation
Authors: Pisani Antonio , Calabresi Paolo , Centonze Diego , Marfia Girolama A. , Bernardi Giorgio
Published: December 2017

Electrophysiological recordings and calcium measurements in striatal large aspiny interneurons in response to combined O2/glucose deprivation. The effects of combined O2/glucose deprivation were investigated on large aspiny (LA) interneurons recorded from a striatal slice preparation by means of simultaneous electrophysiological and optical recordings. LA interneurons were visually identified and impaled with sharp microelectrodes loaded with the calcium (Ca2+)-sensitive dye bis-fura-2. These cells showed the morphological, electrophysiological, and pharmacological features of large striatal cholinergic interneurons. O2/glucose deprivation induced a membrane hyperpolarization coupled to a concomitant increase in intracellular Ca2+concentration ([Ca2+]i). Interestingly, this [Ca2+]ielevation was more pronounced in dendritic branches rather than in the somatic region. The O2/glucose-deprivation-induced membrane hyperpolarization reversed its polarity at the potassium (K+) equilibrium potential. Both membrane hyperpolarization and [Ca2+]irise were unaffected by TTX or by a combination of ionotropic glutamate receptors antagonists,d-2-amino-5-phosphonovaleric acid and 6cyano-7-nitroquinoxaline-2,3-dione. Sulfonylurea glibenclamide, a blocker of ATP-sensitive K+channels, markedly reduced the O2/glucose-deprivation-induced membrane hyperpolarization but failed to prevent the rise in [Ca2+]i. Likewise, charybdotoxin, a large K+-channel (BK) inhibitor, abolished the membrane hyperpolarization but did not produce detectable changes of [Ca2+]ielevation. A combination of high-voltage-activated Ca2+channel blockers significantly reduced both the membrane hyperpolarization and the rise in [Ca2+]i. In a set of experiments performed without dye in the recording electrode, either intracellular bis-( o-aminophenoxy)- N,N,N′,N′-tetraacetic acid or external barium abolished the membrane hyperpolarization induced by O2/glucose deprivation. The hyperpolarizing effect on membrane potential was mimicked by oxotremorine, an M2-like muscarinic receptor agonist, and by baclofen, a GABABreceptor agonist. However, this membrane hyperpolarization was not coupled to an increase but rather to a decrease of the basal [Ca2+]i. Furthermore glibenclamide did not reduce the oxotremorine- and baclofen-induced membrane hyperpolarization. In conclusion, the present results suggest that in striatal LA cells, O2/glucose deprivation activates a membrane hyperpolarization that does not involve ligand-gated K+conductances but is sensitive to barium, glibenclamide, and charybdotoxin. The increase in [Ca2+]iis partially due to influx through voltage-gated high-voltage–activated Ca2+channels.
Sweet Taste Responses of Mouse Chorda Tympani Neurons: Existence of Gurmarin-Sensitive and -Insensitive Receptor Components
Authors: Ninomiya Yuzo , Imoto Toshiaki , Sugimura Tadataka
Published: December 2017

Sweet taste responses of mouse chorda tympani neurons: existence of gurmarin-sensitive and -insensitive receptor components. Inhibitory effects of gurmarin (gur) on responses to sucrose and other sweeteners of single fibers of the chorda tympani nerve in C57BL mice were examined. Of 30 single fibers that strongly responded to 0.5 M sucrose but were not or to lesser extent responsive to 0.1 M NaCl, 0.01 M HCl, and 0.02 M quinine HCl (sucrose-best fibers), 16 fibers showed large suppression of responses to sucrose and other sweeteners by lingual treatment with 4.8 μM (∼20 μg/ml) gur (suppressed to 4–52% of control: gur-sensitive fibers), whereas the remaining 14 fibers showed no such gur inhibition (77–106% of control: gur-insensitive fibers). In gur-sensitive fibers, responses to sucrose inhibited by gur recovered to ∼70% of control responses after rinsing the tongue with 15 mM β-cyclodextrin and were almost abolished by further treatment with 2% pronase. In gur-insensitive fibers, sucrose responses were not inhibited by gur, but were largely suppressed by pronase. These results suggest existence of two different receptor components for sweeteners with different susceptibilities to gur in mouse taste cells, one gur sensitive and the other gur insensitive. Taste cells possessing each component may be specifically innervated by a particular type of chorda tympani neurons.
Neurosteroid Modulation of Synaptic and GABA-Evoked Currents in Neurons From the Rat Medial Preoptic Nucleus
Authors: Haage David , Johansson Staffan
Published: December 2017

The effects of the neurosteroid 3α-hydroxy-5α-pregnane-20-one (allopregnanolone) on synaptic and GABA-evoked currents in acutely dissociated neurons from the medial preoptic nucleus of rat were investigated by perforated-patch recordings under voltage-clamp conditions. The effect of 2.0 μM allopregnanolone on GABA-evoked currents depended strongly on the GABA concentration: the currents evoked by 100 μM GABA were markedly depressed and the desensitization was faster, but the decay after GABA application was prolonged. In contrast, the currents evoked by 1.0 μM GABA were markedly potentiated, the activation was faster, a prominent desensitization was induced, and the decay after GABA application was prolonged. In the absence of externally applied GABA, 2.0 μM allopregnanolone induced a slow current that could be attributed to Cl−. Allopregnanolone did not significantly affect the amplitude of spontaneous tetrodotoxin-insensitive (miniature) synaptic currents (mIPSCs) originating from synaptic terminals releasing GABA onto the dissociated neurons. However, the mIPSC decay phase was dramatically prolonged, with half-maximal effect at ∼50 nM allopregnanolone. A qualitatively similar effect of allopregnanolone was seen when KCl was used to evoke synchronous GABA release. The frequency of mIPSCs was also affected, on average increased 3.5-fold, by 2.0 μM allopregnanolone, suggesting a presynaptic steroid action.
GABAB Receptor Activation Promotes Seizure Activity in the Juvenile Rat Hippocampus
Authors: Motalli Rita , Louvel Jacques , Tancredi Virginia , Kurcewicz Irène , Wan-Chow-Wah Doreen , Pumain René , Avoli Massimo
Published: December 2017

We analyzed how the GABAB receptor agonist baclofen (10–50 μM) influences the activity induced by 4-aminopyridine (4-AP, 50 μM) in the CA3 area of hippocampal slices obtained from 12- to 25-day-old rats. Interictal and ictal discharges along with synchronous GABA-mediated potentials occurred spontaneously in the presence of 4-AP. Baclofen abolished interictal activity ( n = 29 slices) and either disclosed ( n = 21/29) or prolonged ictal discharges ( n = 8/29), whereas GABA-mediated potentials occurred at a decreased rate. The N-methyl-d-aspartate (NMDA) receptor antagonist 3,3-(2-carboxypiperazine-4-yl)-propyl-1-phosphate (CPP, 10 μM, n = 8) did not modify the GABA-mediated potentials or the ictal events recorded in 4-AP + baclofen. In contrast ictal, activity, but not GABA-mediated potentials, was blocked by the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 μM, n = 5). Most baclofen effects were reversed by the GABAB receptor antagonist CGP 35348 (1 mM; n = 4). Baseline and transient increases in [K+]o associated with the 4-AP–induced synchronous activity were unaffected by baclofen. Baclofen hyperpolarized CA3 pyramids ( n = 8) recorded with K-acetate–filled electrodes by 4.8 ± 1.3 mV and made spontaneous, asynchronous hyperpolarizing and depolarizing potentials disappear along with interictal depolarizations. GABA-mediated synchronous long-lasting depolarizations (LLDs) and asynchronous depolarizations were also studied with KCl-filled electrodes in 4-AP + CPP + CNQX ( n = 6); under these conditions baclofen did not reduce LLD amplitude but abolished the asynchronous events. Dentate hilus stimulation at 0.2–0.8 Hz suppressed the ictal activity recorded in 4-AP + baclofen ( n = 8). Our data indicate that GABAB receptor activation by baclofen decreases transmitter release leading to disappearance of interictal activity along with asynchronous excitatory and inhibitory potentials. By contrast, GABA-mediated LLDs and ictal events, which reflect intense action potential firing invading presynaptic inhibitory and excitatory terminals respectively, are not abolished. We propose that the proconvulsant action of baclofen results from 1) block of asynchronous GABA-mediated potentials causing disinhibition and 2) activity-dependent changes in hippocampal network excitability.
Electrophysiological and Morphological Properties of Neurons in the Rat Superior Colliculus. I. Neurons in the Intermediate Layer
Authors: Saito Yasuhiko , Isa Tadashi
Published: December 2017

To begin characterizing the neural elements underlying the dynamic properties of local circuits in the mammalian superior colliculus (SC), electrophysiological and morphological properties of individual neurons in the intermediate layer [stratum griseum intermediale (SGI)] were investigated using whole cell patch-clamp recording and intracellular staining with biocytin in slice preparations from young (17–22 days old) and adult rats (7–8 wk old). Voltage responses to depolarizing current pulses of 223 neurons recorded in young rats were classified into six subclasses: regular-spiking neurons ( n = 113), interspike intervals during depolarizing current pulses were constant; late-spiking neurons ( n = 48), initiation of repetitive firing was delayed markedly from the onset of depolarizing pulses because of a transient hyperpolarization caused by A-like currents; burst-spiking neurons ( n = 29), transient burst firing due to low-threshold Ca2+ channels were observed at the firing threshold level; fast-spiking neurons ( n = 19), constant repetitive firings at frequencies >100 Hz were observed for the duration of the depolarizing pulse; neurons with marked spike frequency adaptation ( n = 11), interspike intervals more than doubled due to spike frequency adaptation during depolarizing pulses; and neurons with rapid spike inactivation ( n = 3), spike amplitude rapidly reduced, width increased during depolarizing pulses, and spiking was terminated after generating a few spikes. In response to hyperpolarizing current pulses, two different types of inward rectification were observed; time-dependent inward rectification by hyperpolarization-activated current ( I h; n = 29) and time-independent inward rectification ( n = 111). Morphological analysis showed that neurons expressing time-dependent inward rectification by I h had large somata, extended divergent dendrites dorsally into the superficial layers, and projected axons ventrally and sometimes dorsally, all characteristic features of wide-field vertical cells. Other neurons exhibited heterogeneous morphological properties, such as multipolar, fusiform, horizontal, or pyramidal-shaped cells. In adult rats, a total of 44 neurons showed similar electrophysiological properties except for the last type. These results indicate that the local circuits of the SC include neurons with at least five different firing properties and two different rectification properties; each with distinct electrophysiological and morphological characteristics that may be correlated with the functional output of the SC.
Neural Mechanisms for Processing Binocular Information II. Complex Cells
Authors: Anzai Akiyuki , Ohzawa Izumi , Freeman Ralph D.
Published: December 2017

Complex cells in the striate cortex exhibit extensive spatiotemporal nonlinearities, presumably due to a convergence of various subunits. Because these subunits essentially determine many aspects of a complex cell receptive field (RF), such as tuning for orientation, spatial frequency, and binocular disparity, examination of the RF properties of subunits is important for understanding functional roles of complex cells. Although monocular aspects of these subunits have been studied, little is known about their binocular properties. Using a sophisticated RF mapping technique that employs binary m-sequences, we have examined binocular interactions exhibited by complex cells in the cat’s striate cortex and the binocular RF properties of their underlying functional subunits. We find that binocular interaction RFs of complex cells exhibit subregions that are elongated along the frontoparallel axis at different binocular disparities. Therefore responses of complex cells are largely independent of monocular stimulus position or phase as long as the binocular disparity of the stimulus is kept constant. The binocular interaction RF is well described by a sum of binocular interaction RFs of underlying functional subunits, which exhibit simple cell-like RFs and a preference for different monocular phases but the same binocular disparity. For more than half of the complex cells examined, subunits of each cell are consistent with the characteristics specified by an energy model, with respect to the number of subunits as well as relationships between the subunit properties. Subunits exhibit RF binocular disparities that are largely consistent with a phase mechanism for encoding binocular disparity. These results indicate that binocular interactions of complex cells are derived from simple cell-like subunits, which exhibit multiplicative binocular interactions. Therefore binocular interactions of complex cells are also multiplicative. This suggests that complex cells compute something analogous to an interocular cross-correlation of images for a local region of visual space. The result of this computation can be used for solving the stereo correspondence problem.
Electrophysiological Assessment of the Cutaneous Arborization of Aδ-Fiber Nociceptors
Authors: Peng Yuan B. , Ringkamp Matthias , Campbell James N. , Meyer Richard A.
Published: December 2017

Little is known about the relationship between the branching structure and function of physiologically identified cutaneous nociceptor terminals. The axonal arborization itself, however, has an impact on the afferent signal that is conveyed along the parent axon to the CNS. We therefore developed electrophysiological techniques to investigate the branching structure of cutaneous nociceptors. Single-fiber recordings were obtained from physiologically identified nociceptors that innervated the hairy skin of the monkey. Electrodes for transcutaneous stimulation were fixed at two separate locations inside the receptive field. For 32 Aδ-fiber nociceptors, distinct steps in latency of the recorded action potential were observed as the intensity of the transcutaneous electrical stimulus increased, indicating discrete sites for action potential initiation. The number of discrete latencies at each stimulation location ranged from 1 to 9 (3.7 ± 0.2; mean ± SE) and the mean size of the latency step was 9.9 ± 1.0 ms (range: 0.4–89.1 ms). For seven Aδ fibers, collision techniques were used to locate the position of the branch point where the daughter fibers that innervated the two locations within the receptive field join the parent axon. To correct for changes in electrical excitability at the peripheral terminals, collision experiments between the two skin locations and between each skin location and a nerve trunk electrode were necessary. Nine branch points were studied in the seven Aδ fibers; the mean propagation time from the action potential initiation site to the branch point was 31 ± 5 ms corresponding to a distance of 54 ± 10 mm. Almost half of the daughter branches were unmyelinated. These results demonstrate that collision techniques can be used to study the functional anatomy of physiologically identified nociceptive afferent terminals. Furthermore these results indicate that some nociceptive afferents branch quite proximal to their peripheral receptive field. Occlusion of action potential activity can occur in these long branches such that the shorter branches dominate in the response to natural stimuli.
Delay-Tuned Neurons in the Inferior Colliculus of the Mustached Bat: Implications for Analyses of Target Distance
Authors: Portfors Christine V. , Wenstrup Jeffrey J.
Published: December 2017

We examined response properties of delay-tuned neurons in the central nucleus of the inferior colliculus (ICC) of the mustached bat. In the mustached bat, delay-tuned neurons respond best to the combination of the first-harmonic, frequency-modulated (FM1) sweep in the emitted pulse and a higher harmonic frequency-modulated (FM2, FM3 or FM4) component in returning echoes and are referred to as FM-FM neurons. We also examined H1-CF2 neurons. H1-CF2 neurons responded to simultaneous presentation of the first harmonic (H1) in the emitted pulse and the second constant frequency (CF2) component in returning echoes. These neurons served as a comparison as they are thought to encode different features of sonar targets than FM-FM neurons. Only 7% of our neurons (14/198) displayed a single excitatory tuning curve. The rest of the neurons (184) displayed complex responses to sounds in two separate frequency bands. The majority (51%, 101) of neurons were facilitated by the combination of specific components in the mustached bat’s vocalizations. Twenty-five percent showed purely inhibitory interactions. The remaining neurons responded to two separate frequencies, without any facilitation or inhibition. FM-FM neurons (69) were facilitated by the FM1 component in the simulated pulse and a higher harmonic FM component in simulated echoes, provided the high-frequency signal was delayed the appropriate amount. The delay producing maximal facilitation (“best delay”) among FM-FM neurons ranged between 0 and 20 ms, corresponding to target distances ≤3.4 m. Sharpness of delay tuning varied among FM-FM neurons with 50% delay widths between 2 and 13 ms. On average, the facilitated responses of FM-FM neurons were 104% greater than the sum of the responses to the two signals alone. In comparing response properties of delay-tuned, FM-FM neurons in the ICC with those in the medial geniculate body (MGB) from other studies, we find that the range of best delays, sharpness of delay tuning and strength of facilitation are similar in the ICC and MGB. This suggests that by the level of the IC, the basic response properties of FM-FM neurons are established, and they do not undergo extensive transformations with ascending auditory processing.
Human Eye-Head Gaze Shifts in a Distractor Task. I. Truncated Gaze Shifts
Authors: Corneil Brian D. , Hing Christine A. , Bautista Dorothy V. , Munoz Douglas P.
Published: December 2017

This study examines two current ideas regarding the control of eye-head gaze shifts. The first idea stems from recent studies involving electrical stimulation in the primate superior colliculus that suggest that a residual feedback of gaze displacement persists for ∼100 ms after completion of a gaze shift. In light of this hypothesis, we examined the accuracy of gaze shifts generated very soon after the end of a preceding gaze shift. Human subjects were presented with a visual or auditory target along with an accompanying stimulus of the other modality. The accompanying stimulus appeared either at the same place as the target or at the diametrically opposite position, in which case it was termed a distractor. Subjects often made an incorrect gaze shift (IGS) in the direction of the distractor, followed by a recorrect gaze shift (RGS) in the direction of the target. We found that RGSs were accurately driven to the target, even when they followed IGSs by <5 ms, regardless of the size of the IGS. The second idea is that a gaze shift cannot be cancelled in midflight. The end point of IGSs frequently fell short of the distractor. The dynamics of these movements, and of the head movement components during the IGSs in particular, suggests that these hypometric IGSs were planned for a much larger excursion but were truncated and superceded by the reversing RGSs. These results emphasize that the gaze shifting system can change the desired goal of a gaze shift in midflight and that the superceding movement is accurate regardless of the metrics or timing of the preceding movement.
Injection of Nicotine Into the Superior Colliculus Facilitates Occurrence of Express Saccades in Monkeys
Authors: Aizawa Hiroshi , Kobayashi Yasushi , Yamamoto Masaru , Isa Tadashi
Published: December 2017

To clarify the role of cholinergic inputs to the intermediate layer of the superior colliculus (SC), we examined the effect of microinjection of nicotine into the SC on visually guided saccades in macaque monkeys. After injection of 0.4–2 μl of 1–100 mM nicotine into the SC, frequency of extremely short latency saccades (express saccades; reaction time = 70–120 ms) dramatically increased, for the saccades the direction and amplitude of which were represented at the location of the injection site on the collicular map. However, no marked change was observed for the relationship between the peak velocities and the amplitudes of saccades. These results suggested that activation of nicotinic acetylcholine receptors in the SC can facilitate initiation but causes no major change in dynamics of visually guided saccades.
Nociceptin Augments K+ Currents in Hippocampal CA1 Neurons by Both ORL-1 and Opiate Receptor Mechanisms
Authors: Madamba Samuel G. , Schweitzer Paul , Siggins George Robert
Published: December 2017

We previously reported (see also the accompanying paper) that dynorphin A significantly enhanced the voltage-dependent K+ M-current ( I M) in CA3 and CA1 hippocampal pyramidal neurons (HPNs). Because the opioid-receptor-like-1 (ORL-1) receptor shares a high sequence homology with opioid receptors and is expressed in rat hippocampus, we examined the effects of orphanin FQ or nociceptin, the endogenous ligand for the ORL-1 receptor, using the rat hippocampal slice preparation and intracellular voltage-clamp recording. Current-voltage ( I-V) relationships from CA1 HPNs revealed that nociceptin superfusion induced an outward current reversing near the equilibrium potential for K+ ions. Ba2+ (2 mM) blocked this effect. The nociceptin-induced current was largest at depolarized membrane potentials, where I M is largely activated. Nociceptin concentrations of 0.5–1 μM (but not 0.1 μM) significantly increased I M relaxation amplitudes with recovery on washout. Interestingly, both the general opiate antagonist naloxone and the κ receptor antagonist nor-binaltorphimine (nBNI) inhibited the nociceptin-induced I Mincreases and outward currents in the depolarized range but not the inward current induced at hyperpolarized potentials. The putative ORL-1 receptor antagonist, [Phe1Ψ(CH2-NH)Gly2]NC(1–13)NH2(hereafter ORLAn), blocked most of the nociceptin current near rest but not the I M increase. However, ORLAn alone had direct effects similar to those of nociceptin, indicating that ORLAn might be a partial agonist. Our results suggest that nociceptin postsynaptically modulates the excitability of HPNs through ORL-1 and κ-like opiate receptors linked to different K+channels.
Dendritic Voltage-Gated Ion Channels Regulate the Action Potential Firing Mode of Hippocampal CA1 Pyramidal Neurons
Authors: Magee Jeffrey C. , Carruth Michael
Published: December 2017

The role of dendritic voltage-gated ion channels in the generation of action potential bursting was investigated using whole cell patch-clamp recordings from the soma and dendrites of CA1 pyramidal neurons located in hippocampal slices of adult rats. Under control conditions somatic current injections evoked single action potentials that were associated with an afterhyperpolarization (AHP). After localized application of 4-aminopyridine (4-AP) to the distal apical dendritic arborization, the same current injections resulted in the generation of an afterdepolarization (ADP) and multiple action potentials. This burst firing was not observed after localized application of 4-AP to the soma/proximal dendrites. The dendritic 4-AP application allowed large-amplitude Na+-dependent action potentials, which were prolonged in duration, to backpropagate into the distal apical dendrites. No change in action potential backpropagation was seen with proximal 4-AP application. Both the ADP and action potential bursting could be inhibited by the bath application of nonspecific concentrations of divalent Ca2+ channel blockers (NiCl and CdCl). Ca2+ channel blockade also reduced the dendritic action potential duration without significantly affecting spike amplitude. Low concentrations of TTX (10–50 nM) also reduced the ability of the CA1 neurons to fire in the busting mode. This effect was found to be the result of an inhibition of backpropagating dendritic action potentials and could be overcome through the coordinated injection of transient, large-amplitude depolarizing current into the dendrite. Dendritic current injections were able to restore the burst firing mode (represented as a large ADP) even in the presence of high concentrations of TTX (300–500 μM). These data suggest the role of dendritic Na+ channels in bursting is to allow somatic/axonal action potentials to backpropagate into the dendrites where they then activate dendritic Ca2+ channels. Although it appears that most Ca2+ channel subtypes are important in burst generation, blockade of T- and R-type Ca2+ channels by NiCl (75 μM) inhibited action potential bursting to a greater extent than L-channel (10 μM nimodipine) or N-, P/Q-type (1 μM ω-conotoxin MVIIC) Ca2+ channel blockade. This suggest that the Ni-sensitive voltage-gated Ca2+ channels have the most important role in action potential burst generation. In summary, these data suggest that the activation of dendritic voltage-gated Ca2+ channels, by large-amplitude backpropagating spikes, provides a prolonged inward current that is capable of generating an ADP and burst of multiple action potentials in the soma of CA1 pyramidal neurons. Dendritic voltage-gated ion channels profoundly regulate the processing and storage of incoming information in CA1 pyramidal neurons by modulating the action potential firing mode from single spiking to burst firing.
Evidence That Wakefulness and REM Sleep Are Controlled by a GABAergic Pontine Mechanism
Authors: Xi Ming-Chu , Morales Francisco R. , Chase Michael H.
Published: December 2017

The pontine microinjection of the inhibitory neurotransmitter GABA and its agonist induced prolonged periods of wakefulness in unanesthetized, chronic cats. Conversely, the application of bicuculline, a GABAA antagonist, resulted in the occurrence of episodes of rapid eye movement (REM) sleep of long duration. Furthermore, administration of antisense oligonucleotides against glutamic acid decarboxylase (GAD) mRNA into the same area produced a significant decrease in wakefulness and an increase in REM sleep. Microinjections of glycine, another major inhibitory neurotransmitter in the CNS, and its antagonist, strychnine, did not have any effect on the behavioral states of sleep and wakefulness. These data argue forcibly that 1) GABAergic neurons play a pivotal role in determining the occurrence of both wakefulness and REM sleep and 2) the functional sequelea of inhibitory GABA actions within the pontine reticular formation are excitatory directives and/or behaviors.
Relationship between Insulin Levels and Nonpsychotic Dementia: A Systematic Review and Meta-Analysis
Authors: Pan Qiu-xia , Li Xiao-juan , Liu Yue-yun , Wang Fang-fang , Hou Ya-jing , Bian Qing-lai , Qiu Wen-qi , Yan Zhi-yi , Jiang You-ming , Chen Jia-xu
Published: December 2017

Objectives. To explore the relationship between insulin levels and nonpsychotic dementia. Methods. Six electronic databases (PubMed, Cochrane, SCI, CNKI, VIP, and Wanfang) were searched from January 1, 2007, to March 1, 2017. Experimental or observational studies that enrolled people with nonpsychotic dementia or abnormal insulin levels in which insulin levels or MMSE scores (events in nonpsychotic dementia) were the outcome measures. Random-effects models were chosen for this meta-analysis. Sample size, mean, s.d., and events were primarily used to generate effect sizes (with the PRIMA registration number CRD42017069860). Results. 50 articles met the final inclusion criteria. Insulin levels in cerebrospinal fluid were lower (Hedges’ g = 1.196, 95% CI = 0.238 to 2.514, and P=0.014), while the levels in peripheral blood were higher in nonpsychotic dementia patients (Hedges’ g = 0.853 and 95% CI = 0.579 to 1.127), and MMSE scores were significantly lower in the high insulin group than in the healthy control group (Hedges’ g = 0.334, 95% CI = 0.249 to 0.419, and P=0.000). Conclusions. Our comprehensive results indicate that blood insulin levels may increase in patients with nonpsychotic dementia.
The Load Capacity Model and Experimental Tests of a New Yielding Steel Prop
Authors: Chen Yanlong , Hao Yang , Wu Yu , Zhang Kai , Zhang Guimin
Published: December 2017

As the mining depth increases year by year, the deformation and failure of deep roadway become more and more serious, and new support equipment with high supporting force and yieldable character is quite necessary for mining safety. In this research, a new yielding steel prop with high stable load capacity was introduced, which features sustaining large deformation in the field. Based on principle stress method and elastic‐plastic theory, a mathematical model of load capacity was proposed for the new prop. The results show that the stable load capacity of the prop increases linearly with the increase of the effective number of the steel balls. Meanwhile, the stable load capacity of the prop increases initially and decreases afterwards with the increase of the radius of the steel ball. Under the fixed radius of the steel ball, the stable load capacity will increase with the decrease of the gap between the inner tube and the outer tube. The stable load capacity of the prop calculated using the theoretical model quantitatively agrees with that of the experimental tests, with only an error within 5%.
Distribution and Seasonal Activity of Phlebotominae Sand Flies in Yazd and Its Outskirts, Center of Iran
Authors: Mirhoseini Motahareh , Salehzadeh Aref , Ramazan Jamaat Sara , Zahirnia Amir Hosein , Rahmanzadeh Najmeh
Published: December 2017

Background. Phlebotominae sand flies are the main vectors of leishmaniasis and some other diseases. Materials and Methods. Using sticky traps, sand flies were collected fortnightly from outdoors and indoors areas of selected sites. Results. A total of 2032 specimens (498 in the city and 1534 in the outskirts of Yazd) belonging to 11 species were collected. The activity of sand flies started in early-April and ended in mid-November. There were two peaks of activity in the end of April and mid-September. Phlebotomus sergenti and P. papatasi were the most abundant species in the city and outskirts of Yazd city, respectively. Other species were P. salehi, P. ansarii, P. kazerouni, P. caucasicus, P. andrejevi, P. alexandri, P. mongolensis, Sergentomyia sintoni, and S. palestinensis. Conclusion. In comparison to some other parts of Iran, the extended period between two peaks suggests that the larvae to adult development of sand fly were delayed by the higher temperature of the summer months in Yazd province.
Treatments for Severe Cutaneous Adverse Reactions
Authors: Cho Yung-Tsu , Chu Chia-Yu
Published: December 2017

Severe cutaneous adverse reaction (SCAR) is life-threatening. It consists of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP), and generalized bullous fixed drug eruptions (GBFDE). In the past years, emerging studies have provided better understandings regarding the pathogenesis of these diseases. These diseases have unique presentations and distinct pathomechanisms. Therefore, theoretically, the options of treatments might be different among various SCARs. However, due to the rarity of these diseases, sufficient evidence is still lacking to support the best choice of treatment for patients with SCAR. Herein, we will provide a concise review with an emphasis on the characteristics and treatments of each SCAR. It may serve as a guidance based on the current best of knowledge and may shed light on the directions for further investigations.