Two-cluster spiking activity induced by a subthreshold periodic stimulus in homogenous neuronal ensembles

Neurons in the arm and orofacial regions of the sensorimotor cortex in behaving monkeys display directional tuning of their activity during arm reaching and tongue protrusion, respectively. While studies on population activity abound for the arm motor cortex, how populations of neurons from the orofacial sensorimotor cortex represent direction has never been described. We therefore examined and compared the directional information contained in the spiking activity of populations of single neurons recorded simultaneously from chronically implanted microelectrode arrays in the orofacial primary motor (MIo, N = 345) and somatosensory (SIo, N = 336) cortices of monkeys ( Macaca mulatta) as they protruded their tongue in different directions. Differential modulation to the direction of tongue protrusion was found in >60% of task-modulated neurons in MIo and SIo and was stronger in SIo ( P < 0.05). Moreover, mutual information between direction and spiking was significantly higher in SIo compared with MIo at force onset and force offset ( P < 0.01). Finally, the direction of tongue protrusion was accurately predicted on a trial-by-trial basis from the spiking activity of populations of MIo or SIo neurons by using a discrete decoder ( P < 0.01). The highly reliable decoding was comparable between MIo and SIo neurons. However, the temporal evolution of the decoding performance differed between these two areas: MIo showed late-onset, fast-rising, and phasic performance, whereas SIo exhibited early-onset, slow-rising, and sustained performance. Overall, the results suggest that both MIo and SIo are highly involved in representing the direction of tongue protrusion but they differ in the amplitude and temporal processing of the directional information distributed across populations of neurons.

Download Full-text

Faculty Opinions recommendation of Independent codes for spatial and episodic memory in hippocampal neuronal ensembles.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1027043.327513 ◽

2005 ◽

Author(s):

Peter Rapp

Keyword(s):

Episodic Memory ◽

Neuronal Ensembles

Download Full-text

Faculty Opinions recommendation of Functionally Distinct Neuronal Ensembles within the Memory Engram.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.737561350.793577202 ◽

2020 ◽

Author(s):

Lu Chen

Keyword(s):

Neuronal Ensembles ◽

Memory Engram

Download Full-text

Information diversity in individual auditory cortical neurons is associated with functionally distinct coordinated neuronal ensembles

Scientific Reports ◽

10.1038/s41598-021-83565-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jermyn Z. See ◽

Natsumi Y. Homma ◽

Craig A. Atencio ◽

Vikaas S. Sohal ◽

Christoph E. Schreiner

Keyword(s):

Cortical Neurons ◽

Single Neuron ◽

Receptive Fields ◽

Acoustic Feature ◽

Neuronal Ensembles ◽

Neuron Spike ◽

Information Diversity ◽

Feature Selectivity ◽

Stimulus Features ◽

Time Specific

AbstractNeuronal activity in auditory cortex is often highly synchronous between neighboring neurons. Such coordinated activity is thought to be crucial for information processing. We determined the functional properties of coordinated neuronal ensembles (cNEs) within primary auditory cortical (AI) columns relative to the contributing neurons. Nearly half of AI cNEs showed robust spectro-temporal receptive fields whereas the remaining cNEs showed little or no acoustic feature selectivity. cNEs can therefore capture either specific, time-locked information of spectro-temporal stimulus features or reflect stimulus-unspecific, less-time specific processing aspects. By contrast, we show that individual neurons can represent both of those aspects through membership in multiple cNEs with either high or absent feature selectivity. These associations produce functionally heterogeneous spikes identifiable by instantaneous association with different cNEs. This demonstrates that single neuron spike trains can sequentially convey multiple aspects that contribute to cortical processing, including stimulus-specific and unspecific information.

Download Full-text

Sensory feedback-dependent coding of arm position in local field potentials of the posterior parietal cortex

Scientific Reports ◽

10.1038/s41598-021-88278-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Paul VanGilder ◽

Ying Shi ◽

Gregory Apker ◽

Christopher A. Buneo

Keyword(s):

Local Field ◽

Sensory Feedback ◽

Posterior Parietal Cortex ◽

Spectral Power ◽

Field Potential ◽

Beta Activity ◽

Beta Band ◽

Arm Position ◽

Multisensory Interactions ◽

Spiking Activity

AbstractAlthough multisensory integration is crucial for sensorimotor function, it is unclear how visual and proprioceptive sensory cues are combined in the brain during motor behaviors. Here we characterized the effects of multisensory interactions on local field potential (LFP) activity obtained from the superior parietal lobule (SPL) as non-human primates performed a reaching task with either unimodal (proprioceptive) or bimodal (visual-proprioceptive) sensory feedback. Based on previous analyses of spiking activity, we hypothesized that evoked LFP responses would be tuned to arm location but would be suppressed on bimodal trials, relative to unimodal trials. We also expected to see a substantial number of recording sites with enhanced beta band spectral power for only one set of feedback conditions (e.g. unimodal or bimodal), as was previously observed for spiking activity. We found that evoked activity and beta band power were tuned to arm location at many individual sites, though this tuning often differed between unimodal and bimodal trials. Across the population, both evoked and beta activity were consistent with feedback-dependent tuning to arm location, while beta band activity also showed evidence of response suppression on bimodal trials. The results suggest that multisensory interactions can alter the tuning and gain of arm position-related LFP activity in the SPL.

Download Full-text

Superimposed gratings induce diverse response patterns of gamma oscillations in primary visual cortex

Scientific Reports ◽

10.1038/s41598-021-83923-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Bin Wang ◽

Chuanliang Han ◽

Tian Wang ◽

Weifeng Dai ◽

Yang Li ◽

...

Keyword(s):

Visual Cortex ◽

Primary Visual Cortex ◽

Field Potential ◽

Gamma Oscillations ◽

Neural Mechanisms ◽

Model Parameters ◽

Response Patterns ◽

Region Difference ◽

High Gamma ◽

Spiking Activity

AbstractStimulus-dependence of gamma oscillations (GAMMA, 30–90 Hz) has not been fully understood, but it is important for revealing neural mechanisms and functions of GAMMA. Here, we recorded spiking activity (MUA) and the local field potential (LFP), driven by a variety of plaids (generated by two superimposed gratings orthogonal to each other and with different contrast combinations), in the primary visual cortex of anesthetized cats. We found two distinct narrow-band GAMMAs in the LFPs and a variety of response patterns to plaids. Similar to MUA, most response patterns showed that the second grating suppressed GAMMAs driven by the first one. However, there is only a weak site-by-site correlation between cross-orientation interactions in GAMMAs and those in MUAs. We developed a normalization model that could unify the response patterns of both GAMMAs and MUAs. Interestingly, compared with MUAs, the GAMMAs demonstrated a wider range of model parameters and more diverse response patterns to plaids. Further analysis revealed that normalization parameters for high GAMMA, but not those for low GAMMA, were significantly correlated with the discrepancy of spatial frequency between stimulus and sites’ preferences. Consistent with these findings, normalization parameters and diversity of high GAMMA exhibited a clear transition trend and region difference between area 17 to 18. Our results show that GAMMAs are also regulated in the form of normalization, but that the neural mechanisms for these normalizations might differ from those of spiking activity. Normalizations in different brain signals could be due to interactions of excitation and inhibitions at multiple stages in the visual system.

Download Full-text