This article reports findings from a study investigating undergraduate biological sciences students' use of technology and computer devices for learning and the effect of providing students with a tablet device. A controlled study was conducted to collect quantitative and qualitative data on the impact of a tablet device on students' use of devices and technology for learning. Overall, we found that students made extensive use of the tablet device for learning, using it in preference to laptop computers to retrieve information, record lectures, and access learning resources. In line with other studies, we found that undergraduate students only use familiar Web 2.0 technologies and that the tablet device did not alter this behavior for the majority of tools. We conclude that undergraduate science students can make extensive use of a tablet device to enhance their learning opportunities without institutions changing their teaching methods or computer systems,but that institutional intervention may be needed to drive changes in student behavior toward the use of novel Web 2.0 technologies.
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Voltage-gated potassium (Kv) channels are essential components of neuronal excitability. The Kv3.4 channel protein is widely distributed throughout the central nervous system (CNS), where it can form heteromeric or homomeric Kv3 channels. Electrophysiological studies reported here highlight a functional role for this channel protein within neurons of the dorsal vagal nucleus (DVN). Current clamp experiments revealed that blood depressing substance (BDS) and intracellular dialysis of an anti-Kv3.4 antibody prolonged the action potential duration. In addition, a BDS sensitive, voltage-dependent, slowly inactivating outward current was observed in voltage clamp recordings from DVN neurons. Electrical stimulation of the solitary tract evoked EPSPs and IPSPs in DVN neurons and BDS increased the average amplitude and decreased the paired pulse ratio, consistent with a presynaptic site of action. This presynaptic modulation was action potential dependent as revealed by ongoing synaptic activity. Given the role of the Kv3 proteins in shaping neuronal excitability, these data highlight a role for homomeric Kv3.4 channels in spike timing and neurotransmitter release in low frequency firing neurons of the DVN.
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The voltage-gated potassium channel subunit Kv3.1 confers fast firing characteristics to neurones. Kv3.1b subunit immunoreactivity (Kv3.1b-IR) was widespread throughout the medulla oblongata, with labelled neurones in the gracile, cuneate and spinal trigeminal nuclei. In the nucleus of the solitary tract (NTS), Kv3.1b-IR neurones were predominantly located close to the tractus solitarius (TS) and could be GABAergic or glutamatergic. Ultrastructurally, Kv3.1b-IR was detected in NTS terminals, some of which were vagal afferents. Whole-cell current-clamp recordings from neurones near the TS revealed electrophysiological characteristics consistent with the presence of Kv3.1b subunits: short duration action potentials (4.2 +/- 1.4 ms) and high firing frequencies (68.9 +/- 5.3 Hz), both sensitive to application of TEA (0.5 m(M))and 4-aminopyridine (4-AP; 30 mum). Intracellular dialysis of an anti-Kv3.1b antibody mimicked and occluded the effects of TEA and 4-AP in NTS and dorsal column nuclei neurones, but not in dorsal vagal nucleus or cerebellar Purkinje cells (which express other Kv3 subunits, but not Kv3.1b). Voltage-clamp recordings from outside-out patches from NTS neurones revealed an outward K+ current with the basic characteristics of that carried by Kv3 channels. In NTS neurones, electrical stimulation of the TS evoked EPSPs and IPSPs, and TEA and 4-AP increased the average amplitude and decreased the paired pulse ratio, consistent with a presynaptic site of action. Synaptic inputs evoked by stimulation of a region lacking Kv3.1b-IR neurones were not affected, correlating the presence of Kv3.1b in the TS with the pharmacological effects.
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Voltage-gated potassium (Kv) channels are critical to regulation of neurotransmitter release throughout the nervous system but the roles and identity of the subtypes involved remain unclear. Here we show that Kv3 channels regulate transmitter release at the mouse neuromuscular junction (NMJ). Light- and electron-microscopic immunohistochemistry revealed Kv3.3 and Kv3.4 subunits within all motor nerve terminals of muscles examined [transversus abdominus, lumbrical and flexor digitorum brevis (FDB)]. To determine the roles of these Kv3 subunits, intracellular recordings were made of end-plate potentials (EPPs) in FDB muscle fibres evoked by electrical stimulation of tibial nerve. Tetraethylammonium (TEA) applied at low concentrations (0.05-0.5 mM), which blocks only a few known potassium channels including Kv3 channels, did not affect muscle fibre resting potential but significantly increased the amplitude of all EPPs tested. Significantly, this effect of TEA was still observed in the presence of the large-conductance calcium-activated potassium channel blockers iberiotoxin (25-150 nM) and Penitrem A (100 nM), suggesting a selective action on Kv3 subunits. Consistent with this, 15-microM 4-aminopyridine, which blocks Kv3 but not large-conductance calcium-activated potassium channels, enhanced evoked EPP amplitude. Unexpectedly, blood-depressing substance-I, a toxin selective for Kv3.4 subunits, had no effect at 0.05-1 microM. The combined presynaptic localization of Kv3 subunits and pharmacological enhancement of EPP amplitude indicate that Kv3 channels regulate neurotransmitter release from presynaptic terminals at the NMJ.
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Neurons in the medial septal/diagonal band complex (MS/DB) in vivo exhibit rhythmic burst-firing activity that is phase-locked with the hippocampal theta rhythm. The aim was to assess the morphology of local axon collaterals of electrophysiologically identified MS/DB neurons using intracellular recording and biocytin injection in vitro. Cells were classified according to previous criteria into slow-firing, fast-spiking, regular-spiking, and burst-firing neurons; previous work has suggested that the slow-firing neurons are cholinergic and that the other types are GABAergic. A novel finding was the existence of two types of burst-firing neuron. Type I burst-firing neurons had significantly longer duration after hyperpolarisation potentials when held at -60 mV, and at -75 mV, type I neurons exhibited a low-threshold spike with more rapid activation and inactivation kinetics than those of type II neurons. We have, also for the first time, described the main features of the local axon collaterals of the five neuron types. All filled neurons possessed a main axon that gave forth 1-12 local primary axon collaterals. All electrophysiological types, except for the type I burst-firing neuron, had a main axon that coursed toward the fornix, Myelination of the main axon was a prominent feature of all but the slow-firing neurons. Branching of the primary axon collaterals of the fast-spiking and type I burst-firing neurons was more extensive than that of the other cell types, with those of the slow-tiring neurons exhibiting the least branching. All cell types possessed axon collaterals of the en passant type, and some in addition had twiglike or basketlike axon terminals. All cell types made synapses on distal dendrites; a proportion of the fast-spiking and burst-firing cells in addition had basketlike terminals that made synaptic contacts on proximal dendrites and on somata. Two morphological types of somata were postsynaptic to the basket cells: large (20-30-mum) oval cells with dark cytoplasm, and large oval cells with paler cytoplasm, often with an apical dendrite. The presence of lamellar bodies in the large dark neurons suggests that they may be cholinergic neurons, because previous work has localised these structures in some neurons that stain for choline acetyltransferase. Our work suggests therefore that there may be GABAergic neurons in the MS/DB that form basket synaptic contacts on at least two types of target cell, possibly cholinergic and GABAergic neurons, which means that the basket cells could play a key role in the generation of rhythmic activity in the MS/DB. J. Comp. Neurol. 430:410-432, 2001. (C) 2001 Wiley-Liss, Inc.
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1. Using patch-clamp techniques, a hyperpolarization-activated current (I-h) was recorded from synaptic terminals of mouse cerebellar basket cells. 2. I-h was blocked quickly and reversibly by 2 mM Cs+, and subtraction revealed a rapidly activating and deactivating I-h current. Similar gating and block of presynaptic I-h were also seen with the more selective inhibitor ZD 7288(10 mu M). 3. The time constant of activation (tau(a)) of presynaptic I-h current became faster with membrane hgperpolarization, being similar to 74 ms at -130 mV, changing e-fold for a 33 mV change in membrane potential. 4. Whole-cell recordings from basket cell somata also revealed an I-h current, which was similarly sensitive to block by ZD 7288. 5. Inhibition of I-h by 10 mu M ZD 7288 reduced the frequency (similar to 34 %) and amplitude (similar to 26 %) of spontaneous IPSCs (sIPSCs) recorded in Purkinje cells, one of the principal synaptic targets of basket neurones. 6. This is the first report of an I-h current in mammalian inhibitory presynaptic terminals, which may be an important target for neuromodulation in the cerebellum. Comparing the biophysical properties and distribution of cloned hyperpolarization-activated cation channels, we also suggest a molecular candidate underlying I-h at these synapses.
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Blended learning, or technology enhanced learning, is increasingly becoming an expectation for higher education students. Blended learning allows for the enhancement of face-to-face interaction between tutors and students, using internet or computer based tools. In this paper, a range of case studies are described which illustrate methods to engage students with technology enhanced learning and improve academic performance and student satisfaction. In the first case study, first year undergraduate students were provided with short video lectures and formative assessment opportunities in addition to face-to-face lectures, and the impact on examination performance was analysed. Results showed that students in multiple cohorts performed significantly better on multiple choice questions that were supported by online blended learning resources. Student usage of the resources was also analysed, and revealed that the majority of students engaged with the online resources after the live teaching event. In the second case study, students were provided with podcasts of lectures with mobile assessments (completed via SMS on mobile telephones) to assess the effect on examination performance and the results showed a significant improvement in academic performance. In the final case study, students have been issued with personal response system handsets to increase interactivity and feedback in teaching sessions. The results of these case studies provide evidence for the use of blended learning approaches to improve students’ academic performance in higher education courses, as well as enhancing student satisfaction.
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