In the rodent primary visual cortex, both pyramidal-to-interneuron connections and interneuron-to-pyramidal connections exist [39], [40], [46].
Current evidence suggests that pyramidal-pyramidal cell connections within CA1 are sparse as compared to neocortical areas or CA3 (Deuchars and Thomson 1996).
The ACC may realize this mobilization via pyramidal cell connections with the amygdala and the locus coeruleus [27], [28] as well as with the anterior and midline thalamic nuclei, which are known to participate in regulating cortical arousal [29].
We use a model of FD that is parameterized with experimental data from a hippocampal basket cell and pyramidal cell connection, for fixed frequency input spikes at frequencies in the range of theta (3 8 Hz) and gamma (20 100 Hz) oscillations.
In fact, FSIs probably do not contribute to coordinating cortical neuronal activity in the perinatal period since FSI-pyramidal cell connections are detected only from PN5 (Pangratz-Fuehrer and Hestrin, 2011).
Interestingly, none of the BS neurons we recorded were synaptically connected with L2/3 pyramidal neurons (20 connections tested); however, one BS-BS connection confirmed the GABAergic nature of this connection (Supplementary Fig. 8).
Surprisingly, none of the NGFCs tested received excitatory input from L2/3 pyramidal neurons (68 connections tested), whereas L2/3 pyramidal neurons had a high probability of connectivity with FS cells (0.35, 7/20 connections tested, significantly different from L2/3 Pyr-NGFC ratio, P < 0.001, Fisher's Exact test, and from L2/3 Pyr-c-AC and L2/3 Pyr-BS ratio, P < 0.05, chi-squared test).
Topography of pyramidal neuron intrinsic connections in macaque monkey prefrontal cortex (areas 9 and 46).
We suggest that this effect may be mediated by broad tufted RS L5 pyramidal neurons forming connections with the pontine nuclei.
We made 185 dual, 84 triple, and 2 quadruple Vm recordings from 630 neighboring (horizontal distance between soma centers, 41.01 ± 0.74 μm; n = 878 tested connections) pyramidal neurons in the primary somatosensory whisker cortex (S1) of urethane anesthetized mice (age, postnatal day 22 ± 0.2 days; n = 188 mice).
A pair of connected pyramidal cells has ∼5 synaptic connections, and induction of an action potential in one cell induces an excitatory postsynaptic potential of approximately 2 mV peak amplitude and 30 msec half-width, as measured in the soma of the other [23].
