Stimulus frequency and meaningfulness varied independently in the learning of word-number pairs.

1971 ◽  
Vol 87 (2) ◽  
pp. 289-291 ◽  
Author(s):  
Marian Schwartz
Keyword(s):  
Stimulus Frequency ◽  
Word Number

Stimulus frequency in continuous short-term recognition memory

1964 ◽  
Author(s):  
Arthur W. Melton ◽  
Harley Bernbach ◽  
Gerald M. Reicher
Keyword(s):  
Recognition Memory ◽  
Stimulus Frequency ◽  
Short Term

Preceding Stimulus Frequency-Dependent Potentiation of the Postrest Shortening of the Action Potential Duration in Rabbits.

2000 ◽  
Vol 41 (4) ◽  
pp. 481-492
Author(s):  
Naohiko Takahashi ◽  
Morio Ito ◽  
Shuji Ishida ◽  
Takao Fujino ◽  
Mikiko Nakagawa ◽  
...  
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Stimulus Frequency ◽  
Frequency Dependent ◽  
Preceding Stimulus

Induction of long-term potentiation without participation of N-methyl-D-aspartate receptors in kitten visual cortex

1991 ◽  
Vol 65 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Y. Komatsu ◽  
S. Nakajima ◽  
K. Toyama
Keyword(s):  
Nmda Receptors ◽  
Stimulus Frequency ◽  
Low Frequency ◽  
Nmda Antagonist ◽  
Long Term Potentiation ◽  
Conditioning Stimulation ◽  
Postsynaptic Potential ◽  
Term Potentiation ◽  
Stimulation Of

1. Intracellular recording was made from layer II-III cells in slice preparations of kitten (30-40 days old) visual cortex. Low-frequency (0.1 Hz) stimulation of white matter (WM) usually evoked an excitatory postsynaptic potential (EPSP) followed by an inhibitory postsynaptic potential (IPSP). The postsynaptic potentials (PSPs) showed strong dependence on stimulus frequency. Early component of EPSP and IPSP evoked by weak stimulation both decreased monotonically at frequencies greater than 0.5-1 Hz. Strong stimulation similarly depressed the early EPSP at higher frequencies (greater than 2 Hz) and replaced the IPSP with a late EPSP, which had a maximum amplitude in the stimulus frequency range of 2-5 Hz. 2. Very weak WM stimulation sometimes evoked EPSPs in isolation from IPSPs. The falling phase of the EPSP revealed voltage dependence characteristic to the responses mediated by N-methyl-D-aspartate (NMDA) receptors and was depressed by application of an NMDA antagonist DL-2-amino-5-phosphonovalerate (APV), whereas the rising phase of the EPSP was insensitive to APV. 3. The early EPSPs followed by IPSPs were insensitive to APV but were replaced with a slow depolarizing potential by application of a non-NMDA antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX), indicating that the early EPSP is mediated by non-NMDA receptors. The slow depolarization was mediated by NMDA receptors because it was depressed by membrane hyperpolarization or addition of APV. 4. The late EPSP evoked by higher-frequency stimulation was abolished by APV, indicating that it is mediated by NMDA receptors, which are located either on the recorded cell or on presynaptic cells to the recorded cells. 5. Long-term potentiation (LTP) of EPSPs was examined in cells perfused with solutions containing 1 microM bicuculline methiodide (BIM), a gamma-aminobutyric acid (GABA) antagonist. WM was stimulated at 2 Hz for 15 min as a conditioning stimulus to induce LTP, and the resultant changes were tested by low-frequency (0.1 Hz) stimulation of WM. 6. LTP of early EPSPs occurred in more than one-half of the cells (8/13) after strong conditioning stimulation. The rising slope of the EPSP was increased 1.6 times on average. 7. To test involvement of NMDA receptors in the induction of LTP in the early EPSP, the effect of conditioning stimulation was studied in a solution containing 100 microM APV, which was sufficient to block completely synaptic transmission mediated by NMDA receptors. LTP occurred in the same frequency and magnitude as in control solution.

Rectification is required to extract oscillatory envelope modulation from surface electromyographic signals

2014 ◽  
Vol 112 (7) ◽  
pp. 1685-1691 ◽  
Author(s):  
Christopher J. Dakin ◽  
Brian H. Dalton ◽  
Billy L. Luu ◽  
Jean-Sébastien Blouin
Keyword(s):  
Motor Unit ◽  
Stimulus Frequency ◽  
Motor Units ◽  
Surface Emg ◽  
Medial Gastrocnemius ◽  
Single Motor Unit ◽  
Single Motor ◽  
Single Motor Units ◽  
Emg Signal ◽  
Envelope Modulation

Rectification of surface electromyographic (EMG) recordings prior to their correlation with other signals is a widely used form of preprocessing. Recently this practice has come into question, elevating the subject of EMG rectification to a topic of much debate. Proponents for rectifying suggest it accentuates the EMG spike timing information, whereas opponents indicate it is unnecessary and its nonlinear distortion of data is potentially destructive. Here we examine the necessity of rectification on the extraction of muscle responses, but for the first time using a known oscillatory input to the muscle in the form of electrical vestibular stimulation. Participants were exposed to sinusoidal vestibular stimuli while surface and intramuscular EMG were recorded from the left medial gastrocnemius. We compared the unrectified and rectified surface EMG to single motor units to determine which method best identified stimulus-EMG coherence and phase at the single-motor unit level. Surface EMG modulation at the stimulus frequency was obvious in the unrectified surface EMG. However, this modulation was not identified by the fast Fourier transform, and therefore stimulus coherence with the unrectified EMG signal failed to capture this covariance. Both the rectified surface EMG and single motor units displayed significant coherence over the entire stimulus bandwidth (1–20 Hz). Furthermore, the stimulus-phase relationship for the rectified EMG and motor units shared a moderate correlation ( r = 0.56). These data indicate that rectification of surface EMG is a necessary step to extract EMG envelope modulation due to motor unit entrainment to a known stimulus.

EEG Synchronized TMS for Individualized Therapy in Major Depressive Disorder

2011 ◽  
Vol 26 (S2) ◽  
pp. 1144-1144
Author(s):  
Y. Jin ◽  
J. Phillips ◽  
Yueqin Huang ◽  
Steven Heurta
Keyword(s):  
Major Depressive Disorder ◽  
Side Effects ◽  
Depressive Disorder ◽  
Active Treatment ◽  
Rating Scale ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Stimulus Frequency ◽  
List Type ◽  
Major Depressive ◽  
Double Blind

IntroductionEfficacy of conventional repetitive transcranial magnetic stimulation (rTMS) in major depressive disorder (MDD) is limited. The authors report here on an alternative treatment using low energy synchronized TMS (sTMS) at the intrinsic frequency of subjects’ alpha electroencephalogram (EEG).ObjectivesEstablish efficacy and safety profile of sTMS in MDD.Aim(1)Examine the clinical effectiveness of sTMS.(2)Identify adverse effects associated with sTMS.MethodsFifty-two MDD subjects with 17-item Hamilton Depression Rating Scale (HAMD17) scores >17 were enrolled into a randomized, sham controlled, double-blind trial. Current medication remained unchanged during the trial. Depressive symptoms were evaluated by HAMD17 administered weekly.EEGs were recorded at baseline to determine the stimulus frequency and at week 4 to evaluate the physiological effect. sTMS was delivered through three 6000-G cylindrical neodymium magnets synchronously rotating at a rate equal to the subject's intrinsic alpha frequency.ResultsForty-five subjects completed at least 1 week of treatment and were evaluable. Those who received active treatment had superior clinical response to sham (t = 2.54, P = 0.01), where 55.2% in the active treatment group were clinical responders versus 12.5% in sham (X2 = 7.82, P = 0.005). No significant side effects were reported. The clinical improvement was correlated with the degree of EEG improvement (r = .46, P = 0.009).ConclusionsA therapeutic effect in MDD subjects can be achieved through administration of sTMS at the subject's alpha EEG frequency. Because of minimal side effects, this appears to be a safe and effective treatment option.

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