scholarly journals Local field potentials are local events in the mouse auditory cortex

2015 ◽  
Vol 42 (6) ◽  
pp. 2289-2297 ◽  
Author(s):  
Xiuping Liu ◽  
Linran Zhou ◽  
Fangchao Ding ◽  
Yehan Wang ◽  
Jun Yan
Keyword(s):  
Auditory Cortex ◽  
Local Field ◽  
Local Field Potentials ◽  
Field Potentials

Differential thresholds of local field potentials and unit discharges in rat auditory cortex

2002 ◽  
Vol 167 (1-2) ◽  
pp. 57-60 ◽  
Author(s):  
Veronica V Galván ◽  
Jemmy Chen ◽  
Norman M Weinberger
Keyword(s):  
Auditory Cortex ◽  
Local Field ◽  
Local Field Potentials ◽  
Field Potentials

Synchrony between single-unit activity and local field potentials in relation to periodicity coding in primary auditory cortex

1995 ◽  
Vol 73 (1) ◽  
pp. 227-245 ◽  
Author(s):  
J. J. Eggermont ◽  
G. M. Smith
Keyword(s):  
Auditory Cortex ◽  
Local Field ◽  
Single Unit ◽  
Transfer Functions ◽  
Local Field Potentials ◽  
Primary Auditory Cortex ◽  
Single Units ◽  
Field Potentials ◽  
Level Crossings ◽  
Low Pass

1. We recorded responses from 136 single units and the corresponding local field potentials (LFPs) from the same electrode at 44 positions in the primary auditory cortex of 25 juvenile, ketamine-anesthetized cats in response to periodic click trains with click repetition rates between 1 and 32 Hz; to Poisson-distributed click trains with an average click rate of 4 Hz; and under spontaneous conditions. The aim of the study is to evaluate the synchrony between LFPs and single-unit responses, to compare their coding of periodic stimuli, and to elucidate mechanisms that limit this periodicity coding in primary auditory cortex. 2. We obtained averaged LFPs either as click-triggered averages, the classical evoked potentials, or as spike-triggered averages. We quantified LFPs by initial negative peak-to-positive peak amplitude. In addition, we obtained trigger events from negativegoing level crossings (at approximately 2 SD below the mean) of the 100-Hz low-pass electrode signal. We analyzed these LFP triggers similarly to single-unit spikes. 3. The average ratio of the LFP amplitude in response to the second click in a train and the LFP amplitude to the first click as a function of click rate was low-pass with a slight resonance at approximately 10 Hz, and, above that frequency, decreasing with a slope of approximately 24 dB/octave. We found the 50% point at approximately 16 Hz. In contrast, the LFP amplitude averaged over entire click trains was low-pass with a similar resonance but a high-frequency slope of 12 dB/octave and a 50% point at approximately 12 Hz. 4. The LFP amplitude for click repetition rates between 5 and 11 Hz often showed augmentation, i.e., the amplitude increased in response to the first few clicks in the train and thereafter decreased. This augmentation was paralleled by an increase in the probability of firing in single units simultaneously recorded on the same electrode. 5. We calculated temporal modulation transfer functions (tMTFs) for single-unit spikes and for LFP triggers. They were typically bandpass with a best modulating frequency of 10 Hz and similar shape for both single-unit spikes and LFP triggers. The tMTF per click, obtained by dividing the tMTF by the number of clicks in the train, was low-pass with a 50% cutoff frequency at approximately Hz, similar to that for the average LFP amplitude. 6. the close similarity of the tMTFs for single-unit spikes and LFP triggers suggests that single-unit tMTFs can be predicted from LFP level crossings.(ABSTRACT TRUNCATED AT 400 WORDS)

Local Field Potentials and Spiking Activity in the Primary Auditory Cortex in Response to Social Calls

2004 ◽  
Vol 92 (1) ◽  
pp. 52-65 ◽  
Author(s):  
Andrei V. Medvedev ◽  
Jagmeet S. Kanwal
Keyword(s):  
Auditory Cortex ◽  
Fundamental Frequency ◽  
Local Field ◽  
Dimensional Space ◽  
Temporal Structure ◽  
Local Field Potentials ◽  
Primary Auditory Cortex ◽  
Spectral Structure ◽  
Field Potentials ◽  
Spiking Activity

The mustached bat, Pteronotus parnellii, uses complex communication sounds (“calls”) for social interactions. We recorded both event-related local field potentials (LFPs) and single/few-unit (SU) spike activity from the same electrode in the posterior region of the primary auditory cortex (AIp) during presentation of simple syllabic calls to awake bats. Temporal properties of the LFPs, which reflect activity within local neuronal clusters, and spike discharges from SUs were studied at 138 recording sites in six bats using seven variants each of 14 simple syllables presented at intensity levels of 40–90 dB SPL. There was no clear spatial selectivity to different call types within the AIp area. Rather, as shown previously, single units responded to multiple call types with similar values of the peak response rate in the peri-stimulus time histogram (PSTH). The LFPs and SUs, however, showed a rich temporal structure that was unique for each call type. Multidimensional scaling (MDS) of the averaged waveforms of call-evoked LFPs and PSTHs revealed that calls were better segregated in the two-dimensional space based on the LFP compared with the PSTH data. A representation within the “LFP-space” revealed that one of the dimensions correlated with the predominant and fundamental frequency of a call. The other dimension showed a high correlation with “harmonic complexity” (“fine” spectral structure of a call). We suggest that the temporal pattern of LFP and spiking activity reflects call-specific dynamics at any locus within the AIp area. This dynamic contributes to a distributed (population-based) representation of calls. Alternatively stated, the fundamental frequency and harmonic structure of calls, and not the recording location within the AIp, determines the temporal structure of the call-evoked LFP.

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