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| Home > Publications database > Behaviorally Relevant Spatio-Temporal Spike Patterns in Parallel Spike Trains |
| Poster (After Call) | FZJ-2021-03096 |
; ; ;
2021
Please use a persistent id in citations: http://hdl.handle.net/2128/28440
Abstract: The Hebbian hypothesis [1] states that neurons organize in assemblies of co-active neuronsacting as information processing units. We hypothesize that assembly activity is expressedby the occurrence of precise spatio-temporal patterns (STPs) of spikes - with precisetemporal delays between the spikes - emitted by neurons that presumably are members ofan assembly.We developed a method, called SPADE [2,3,4], that detects significant STPs in massivelyparallel spike trains. SPADE involves three steps: it first identifies repeatingSTPs using Frequent Itemset Mining [5]; second, it evaluates the detected patterns forsignificance through surrogates (trial-shifting); third, it removes the false positive patternsthat are a by-product of true patterns and the background activity.Here, we aim to evaluate if cell assemblies are active in relation to motor behavior [2].Therefore, we analyzed N=20 experimental sessions consisting of about 100 parallel spiketrains recorded by a 100-electrode Utah array in the pre-/motor cortex of two macaquemonkeys performing a reach-to-grasp task [6,7]. In this task, the monkey, after an instructedpreparatory period, had to pull and hold an object by using either a side or a precision grip,and using either high or low force (four behavioral conditions). We segmented trials into 500ms periods and concatenated them to analyze separately for the occurrence of STPs. Eachsignificant STP is identified by its neuron composition, its number and times of occurrencesand the delays between spikes of the pattern. The temporal resolution of the detectedpatterns is fixed to 5ms.We find that STPs occur in all phases of the behavior. In particular, we find about 6 patternsper session, where only 3 to 13 individual neurons are involved in STPs. Pattern can repeatfrom 280 to 10 times, depending on the size, which varies from 2 to 6 neurons. Within asession, patterns strongly depend on the behavioral context, and we do not find identicalpatterns in the different epochs. Thus, patterns are specific to a behavioral condition,suggesting that different assemblies are activated for each specific behavioral context.Patterns that occur in a single session typically overlap in the participating neurons, and afew individual neurons appear as hubs, i.e. are involved in several patterns. We also findthat pattern neurons are not located within a small region, but distributed across the entirecortical surface covered by the Utah array.Our results are consistent with the model of the synfire chain (SFC) [8]. A theoretical studyshowed [9] that patterns emerging from SFC activity can be found in parallel spike train datarecorded with a 100-electrode Utah array, i.e. despite the strong subsampling.References[1] Hebb, D. O. (1949). John Wiley & Sons.[2] Torre et al (2016) J Neurosci. DOI: 10.1523/JNEUROSCI.4375-15.2016.[3] Quaglio et al. (2017). Front Comp Neurosci,. DOI: 10.3389/fncom.2017.00041.[4] Stella et al. (2019). Biosystems. DOI:10.1016/j.biosystems.2019.104022.[5] Pormann et al. (2021). Submitted.[6] Brochier et al. (2018). Scientific data. DOI: 10.1038/sdata.2018.55.[7] Riehle et al. (2013). Front. Neural Circuits. DOI: 10.3389/fncir.2013.00048.[8] Abeles (1991) Cambridge University Press.[9] Berling, David (2020). Master thesis in physics, RWTH Aachen Univ., Germany.
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