A cumulative sum test for a peri-stimulus time histogram using the Monte Carlo method

Ushiba, Junichi; Tsutsumi, Yutaka; Masakado, Yoshihisa; Komune, Y.

doi:10.1016/s0165-0270(02)00145-0

Cited by 16 publications

(3 citation statements)

References 41 publications

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“…This computation allowed identification of periods of reduction or increase in firing probability, which should correspond to an inhibitory or an excitatory effect on the motoneuron (see Gustafsson & McCrea, 1984). To identify the onset of an effect, the cumulative sum technique (see Ellaway, 1978), coupled to the Monte Carlo method (see Ushiba et al ., 2002), was used. In fact, with this procedure the operator can set the limit of the windows in which a statistical analysis will be performed.…”

Section: Methodssupporting

confidence: 79%

Mechanical and focal electrical stimuli applied to the skin of the index fingertip induce both inhibition and excitation in low‐threshold flexor carpi radialismotor units

Lourenço

Caronni²,

Cavallari³

2007

Eur J of Neuroscience

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It has been observed that mechanical stimulation of the skin of the index fingertip causes a weak short-latency inhibition followed by a strong long-lasting facilitation of the flexor carpi radialis (FCR) H-reflex. Based on threshold and latency, these cutaneous reflexes are thought to be routed to motoneurons by parallel pathways. As recent studies have shown predominant inhibitory potentials in slow motoneurons and predominant excitatory potentials in faster ones, the question arises as to whether or not the two cutaneous pathways converge onto the same motoneuron. The poststimulus time histogram technique was used to investigate the changes in firing frequency of low-threshold FCR motor units (MUs), induced by passive mechanical or focal electrical stimuli to the index skin. After gently tapping the finger pulp a small sharp inhibition appeared in 20 MUs. On average, inhibition started 10.2 ± 1.6 ms from the homonymous Ia monosynaptic effect, and its central delay was estimated to be 1.2 ± 1.6 ms. The subsequent facilitation, more consistent, had a mean latency of 13.5 ± 1.7 ms. Inhibition and excitation were statistically significant (P < 0.05). A similar biphasic effect was observed in seven other FCR-MUs, also after focal electrical stimulation of the same skin area. Comparison with the time course of the H-reflex, representing the whole population of MUs, showed striking similarities in time course and latency to the present MU effect. It is thus suggested that cutaneous spinal pathways may have a homogeneous distribution within the FCR motoneuron pool, and that the skewed distribution of cutaneous afferents onto motoneurons should be not taken as a rule.

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Section: Methodssupporting

confidence: 79%

Mechanical and focal electrical stimuli applied to the skin of the index fingertip induce both inhibition and excitation in low‐threshold flexor carpi radialismotor units

Lourenço

Caronni²,

Cavallari³

2007

Eur J of Neuroscience

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“…The response window was defined as the 500 msec period beginning at the onset of the 200 msec stimulus pulse. A unit was considered to be responsive if its control-subtracted PSTH was above (excitatory) or below (inhibitory) the 95% confidence limits derived from a cumulative sum (CUMSUM) test based on the Monte Carlo method (Ushiba et al, 2002). Inspection of the entire 118 unit data set revealed that a 500 msec window was sufficient to capture all of the 1000ϩ stimulus-evoked responses recorded.…”

Section: Methodsmentioning

confidence: 99%

Spatial and Temporal Organization of Ensemble Representations for Different Odor Classes in the Moth Antennal Lobe

2004

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In the insect antennal lobe, odor discrimination depends on the ability of the brain to read neural activity patterns across arrays of uniquely identifiable olfactory glomeruli. Less is understood about the complex temporal dynamics and interglomerular interactions that underlie these spatial patterns. Using neural-ensemble recording, we show that the evoked firing patterns within and between groups of glomeruli are odor dependent and organized in both space and time. Simultaneous recordings from up to 15 units per ensemble were obtained from four zones of glomerular neuropil in response to four classes of odorants: pheromones, monoterpenoids, aromatics, and aliphatics. Each odor class evoked a different pattern of excitation and inhibition across recording zones. The excitatory response field for each class was spatially defined, but inhibitory activity was spread across the antennal lobe, reflecting a center-surround organization. Some chemically related odorants were not easily distinguished by their spatial patterns, but each odorant evoked transient synchronous firing across a uniquely different subset of ensemble units. Examination of 535 cell pairs revealed a strong relationship between their recording positions, temporal correlations, and similarity of odor response profiles. These findings provide the first definitive support for a nested architecture in the insect olfactory system that uses both spatial and temporal coordination of firing to encode chemosensory signals. The spatial extent of the representation is defined by a stereotyped focus of glomerular activity for each odorant class, whereas the transient temporal correlations embedded within the ensemble provide a second coding dimension that can facilitate discrimination between chemically similar volatiles.

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“…5b). The confidence interval was calculated in accordance with the technique previously reported (USHIBA et al, 2002a;2003b). As a result of the CUSUM test, a significant increase was detected at 49 ms.…”

mentioning

confidence: 96%

Integration-plot test for peri-stimulus time histograms in human motor units

Ushiba

Honda

Onishi

et al. 2004

Med. Biol. Eng. Comput.

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A statistical test is proposed for peri-stimulus time histograms in human motor units for the case where a test stimulus is delivered at a constant interval after a previous discharge. This mathematically described test included the notion of the multiple comparison and thus achieved higher sensitivity than the previously proposed method. With regard to data acquisition, the interval from a sham stimulus to the next discharge was acquired as a control, and the total number of samples was set to be four times as large as that in the test situation to reduce the statistical scattering noise. A newly defined statistical object, the integration plot (timewise accumulation of the test histogram without control subtraction) was used for this statistical test. The integration plot had less noise than the cumulative sum (CUSUM) plot (1/square root(2) in theory) and thus represented the neural effect. To compare this integration-plot test with that of the CUSUM, a simulation experiment that compared two sample histograms (one of which had a faint structural change from 20 ms) was conducted. As a result, the present test succeeded in detecting the onset of the change point earlier (23 ms on average) than the CUSUM test (27 ms on average), and the detection probability was also higher (9 out of 10) than the CUSUM (6 out of 10). It was therefore confirmed experimentally that the present statistical test had higher sensitivity than that of the CUSUM proposed previously.

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A cumulative sum test for a peri-stimulus time histogram using the Monte Carlo method

Cited by 16 publications

References 41 publications

Mechanical and focal electrical stimuli applied to the skin of the index fingertip induce both inhibition and excitation in low‐threshold flexor carpi radialismotor units

Mechanical and focal electrical stimuli applied to the skin of the index fingertip induce both inhibition and excitation in low‐threshold flexor carpi radialismotor units

Spatial and Temporal Organization of Ensemble Representations for Different Odor Classes in the Moth Antennal Lobe

Integration-plot test for peri-stimulus time histograms in human motor units

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