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Fig. 1 | Bioelectronic Medicine

Fig. 1

From: The impact of closed-loop intracortical stimulation on neural activity in brain-injured, anesthetized animals

Fig. 1

Experimental protocol. A) Areas of interest were stereotaxically located under anesthetized conditions. Two multisite MEAs (see B for details) were placed in the left hemisphere, i.e. in the Rostral Forelimb Area – RFA for recording, and in the Primary Somatosensory area - S1 for recording and stimulation. B) Schematic representation of the setup (created with BioRender.com). Two 4 shank, 16 contact site MEAs were inserted into the cortex. Top: raw signals of spontaneous activity during the PreStim phase (see C for details) in the recording sites (i.e. RFA and S1). C) Experimental timeline of the two experimental groups, i.e. CTR (Control – lesioned, not stimulated) and ADS (lesioned and stimulated). Both CTR and ADS were characterized by one phase of lesion induction, where no recording was performed (dotted line). Control experiments (top sketch) were characterized by five phases of recording spontaneous activity (i.e., PreLesion - grey, PreStim - light blue and PostStim - green of 20 min each, PostLesion and Stim of 60 min each). For the Stim phase, the stimulation current was set to 0A for the entire recording time of 60 min. During data analysis PostLesion was split into three 20 min subphases (i.e., PoL1, PoL2, and PoL3 - cherry red). The ADS experiments (bottom sketch) were characterized by three phases, the middle one consisting of 60 min of stimulation (Stim) where current was delivered in the form of biphasic squared pulses at 60 μA, while the other two were characterized by 20 min of spontaneous activity recording, during which no stimulation was applied (i.e., PreStim and PostStim). D) Block diagram of data analysis. Briefly, raw data was filtered with a bandpass filter (300–3000 Hz); a custom offline spike detection was used to perform spike discrimination; a superparamagnetic clustering sorted the detected spikes and finally a supervised visual assessment of sorted clusters was used to validate the spike profiles. Spike profiles were then utilized for Mean Firing Rate, Bootstrapping and Local Variation compensate for Refractoriness (LvR) analyses (see text)

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