Abstract
The networks of neocortical neurons are coordinated by spontaneous activity, the level of which exhibits high heterogeneity among neurons, ranging from low activity levels to very high activity levels, even in the same network. Highly active neurons represent a small proportion in the cerebral cortex and are mingled in a web of the vast majority of neurons with low firing rates. However, little is known about the spatial arrangement of these highly active cells within the cerebral cortex. Here, we visualized their spatial distribution by labeling them with c-Fos, a neuronal activity marker, in the mouse primary visual cortex. By introducing energy-like and entropy-like parameters that did not require arbitrary thresholds for c-Fos positivity, we found that strongly c-Fos-expressing neurons were clustered in the vicinity. The cluster size measured approximately 100 μm in diameter and was smaller in layer 2/3 than in layers 5 and 6. Layer 1 neurons did not exhibit a clustered pattern of c-Fos-expressing neurons. Our novel statistical approaches are not subject to human bias and are thus widely applicable to evaluate the spatial bias of any particles.
Similar content being viewed by others
References
Barth AL, Poulet JF (2012) Experimental evidence for sparse firing in the neocortex. Trends Neurosci 35:345–355
Beloozerova IN, Sirota MG, Swadlow HA (2003) Activity of different classes of neurons of the motor cortex during locomotion. J Neurosci 23:1087–1097
Benedetti BL, Takashima Y, Wen JA, Urban-Ciecko J, Barth AL (2013) Differential wiring of layer 2/3 neurons drives sparse and reliable firing during neocortical development. Cereb Cortex 23:2690–2699
Brown SP, Hestrin S (2009) Intracortical circuits of pyramidal neurons reflect their long-range axonal targets. Nature 457:1133–1136
Buzsaki G, Mizuseki K (2014) The log-dynamic brain: how skewed distributions affect network operations. Nat Rev Neurosci 15:264–278
Connors BW, Gutnick MJ (1990) Intrinsic firing patterns of diverse neocortical neurons. Trends Neurosci 13:99–104
de Kock CP, Sakmann B (2009) Spiking in primary somatosensory cortex during natural whisking in awake head-restrained rats is cell-type specific. Proc Natl Acad Sci USA 106:16446–16450
de Kock CP, Bruno RM, Spors H, Sakmann B (2007) Layer- and cell-type-specific suprathreshold stimulus representation in rat primary somatosensory cortex. J Physiol 581:139–154
Dickey AS, Suminski A, Amit Y, Hatsopoulos NG (2009) Single-unit stability using chronically implanted multielectrode arrays. J Neurophysiol 102:1331–1339
Dragunow M, Faull R (1989) The use of c-fos as a metabolic marker in neuronal pathway tracing. J Neurosci Methods 29:261–265
Fraser GW, Schwartz AB (2012) Recording from the same neurons chronically in motor cortex. J Neurophysiol 107:1970–1978
Gall CM, Hess US, Lynch G (1998) Mapping brain networks engaged by, and changed by, learning. Neurobiol Learn Mem 70:14–36
Hira R, Ohkubo F, Ozawa K et al (2013) Spatiotemporal dynamics of functional clusters of neurons in the mouse motor cortex during a voluntary movement. J Neurosci 33:1377–1390
Hromadka T, Deweese MR, Zador AM (2008) Sparse representation of sounds in the unanesthetized auditory cortex. PLoS Biol 6:e16
Jackson A, Fetz EE (2007) Compact movable microwire array for long-term chronic unit recording in cerebral cortex of primates. J Neurophysiol 98:3109–3118
Jouhanneau JS, Ferrarese L, Estebanez L et al (2014) Cortical fosGFP expression reveals broad receptive field excitatory neurons targeted by POm. Neuron 84:1065–1078
Kanda T, Sullivan KF, Wahl GM (1998) Histone-GFP fusion protein enables sensitive analysis of chromosome dynamics in living mammalian cells. Curr Biol 8:377–385
Kenet T, Bibitchkov D, Tsodyks M, Grinvald A, Arieli A (2003) Spontaneously emerging cortical representations of visual attributes. Nature 425:954–956
Ko H, Cossell L, Baragli C et al (2013) The emergence of functional microcircuits in visual cortex. Nature 496:96–100
Krook-Magnuson E, Varga C, Lee SH, Soltesz I (2012) New dimensions of interneuronal specialization unmasked by principal cell heterogeneity. Trends Neurosci 35:175–184
Lerea LS, Butler LS, McNamara JO (1992) NMDA and non-NMDA receptor-mediated increase of c-fos mRNA in dentate gyrus neurons involves calcium influx via different routes. J Neurosci 12:2973–2981
Mank M, Santos AF, Direnberger S et al (2008) A genetically encoded calcium indicator for chronic in vivo two-photon imaging. Nat Methods 5:805–811
Maruoka H, Kubota K, Kurokawa R, Tsuruno S, Hosoya T (2011) Periodic organization of a major subtype of pyramidal neurons in neocortical layer V. J Neurosci 31:18522–18542
McCormick DA, Connors BW, Lighthall JW, Prince DA (1985) Comparative electrophysiology of pyramidal and sparsely spiny stellate neurons of the neocortex. J Neurophysiol 54:782–806
Meyer HS, Wimmer VC, Oberlaender M, de Kock CP, Sakmann B, Helmstaedter M (2010) Number and laminar distribution of neurons in a thalamocortical projection column of rat vibrissal cortex. Cereb Cortex 20:2277–2286
Minamisawa G, Funayama K, Matsuki N, Ikegaya Y (2011) Intact internal dynamics of the neocortex in acutely paralyzed mice. J Physiol Sci 61:343–348
Mizuseki K, Buzsaki G (2013) Preconfigured, skewed distribution of firing rates in the hippocampus and entorhinal cortex. Cell Rep 4:1010–1021
Molnar Z, Cheung AF (2006) Towards the classification of subpopulations of layer V pyramidal projection neurons. Neurosci Res 55:105–115
Morgan JI, Curran T (1991) Stimulus-transcription coupling in the nervous system: involvement of the inducible proto-oncogenes fos and jun. Annu Rev Neurosci 14:421–451
Morishima M, Kawaguchi Y (2006) Recurrent connection patterns of corticostriatal pyramidal cells in frontal cortex. J Neurosci 26:4394–4405
Morishima M, Morita K, Kubota Y, Kawaguchi Y (2011) Highly differentiated projection-specific cortical subnetworks. J Neurosci 31:10380–10391
O’Connor DH, Peron SP, Huber D, Svoboda K (2010) Neural activity in barrel cortex underlying vibrissa-based object localization in mice. Neuron 67:1048–1061
Poulet JF, Petersen CC (2008) Internal brain state regulates membrane potential synchrony in barrel cortex of behaving mice. Nature 454:881–885
Sagar SM, Sharp FR, Curran T (1988) Expression of c-fos protein in brain: metabolic mapping at the cellular level. Science 240:1328–1331
Sakata S, Harris KD (2009) Laminar structure of spontaneous and sensory-evoked population activity in auditory cortex. Neuron 64:404–418
Slomianka L, Amrein I, Knuesel I, Sorensen JC, Wolfer DP (2011) Hippocampal pyramidal cells: the reemergence of cortical lamination. Brain Struct Funct 216:301–317
Yassin L, Benedetti BL, Jouhanneau JS, Wen JA, Poulet JF, Barth AL (2010) An embedded subnetwork of highly active neurons in the neocortex. Neuron 68:1043–1050
Yoshimura Y, Dantzker JL, Callaway EM (2005) Excitatory cortical neurons form fine-scale functional networks. Nature 433:868–873
Acknowledgments
We are grateful to Dr. Hiroyuki Hioki (Kyoto University) for providing us with anti-vGluT2 antibody. This work was supported by Grants-in-Aid for Science Research on Innovative Areas (22115003; 25119004).
Conflict of interest
We declare no conflict of interest.
Author information
Authors and Affiliations
Corresponding author
Additional information
K. Makino and K. Funayama contributed equally to this work.
Rights and permissions
About this article
Cite this article
Makino, K., Funayama, K. & Ikegaya, Y. Spatial clusters of constitutively active neurons in mouse visual cortex. Anat Sci Int 91, 188–195 (2016). https://doi.org/10.1007/s12565-015-0284-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12565-015-0284-z