Comment on Journal Club: Closing the Loop from Brain Cells to Behavior

[Timothy Busbice]

I can add volumes to the research going on here, but one thing that stuck out is at around 1:49, Stephen's comments were right on. From my own connectome modeling, I found this to be true:

The connectome is always on. I did a test and after initial stimulation, the connectome continued to run for 24 hours and if I hadn’t stopped it, probably would have gone on forever.

The connectome is highly recurrent and further analysis shows that the connectome is exponentially recurrent.

Each neuron connects to a set of other neurons and as they are stimulated, a subset will connect back to the originating neuron. This connection back to the originating neuron grows exponentially the deeper the stimulation.

Doing some simple analysis that anyone can perform, this chart shows how recursive the connectome circuit is:

Neuron	Type	Layer 1	Layer 2	Layer 3	Layer 4	Layer 5
AVAL	Interneuron	83	573	10109	133806	2106961
AVAR	Interneuron	76	579	9438	126040	2008160
AVBL	Interneuron	34	248	3947	63622	1076829
AVBR	Interneuron	38	264	3911	60843	1022206
AVDL	Interneuron	10	97	1505	25148	429624
AVDR	Interneuron	10	87	1438	24853	433548
AVEL	Interneuron	7	65	1144	20138	356197
AVER	Interneuron	7	56	1047	18432	330160
AVFL	Interneuron	16	85	592	5194	58868
AVFR	Interneuron	14	82	576	5385	64701
AVG	Interneuron	4	13	126	1559	22023
AVHL	Interneuron	15	73	702	9037	137806
AVHR	Interneuron	13	57	437	4300	57851
AVJL	Interneuron	17	137	1886	29663	505108
AVJR	Interneuron	6	48	654	10448	175900
AVKL	Interneuron	21	105	1166	15662	246684
AVKR	Interneuron	13	55	576	7120	101256
BDUL	Interneuron	3	3	62	683	10629
BDUR	Interneuron	4	11	108	1262	19303
DVA	Interneuron	16	96	1653	25453	442670
DVC	Interneuron	13	54	770	11402	189026

In this chart, AVAL connects to a set of neurons and out of that set, there are 83 connections back to AVAL. That set of neurons connects to another set, and out of that, 573 neurons connect back to AVAL, etc, etc until you get to 5 layers deep and you can see that 2 million connections come back to AVAL. As can be predicted, the Interneurons have a much higher recurrency than do motor or sensory neurons.

--

Timothy Busbice

CTO - Connectomix

Connectomes as a Service