. 2008 Mar 28;4(3):e1000036. doi: 10.1371/journal.pcbi.1000036

Table 1. Expected Traveling Time of Different Means of Signaling. (Calculated for 40 µm synapse-to-nucleus distance, which correspond to ∼30^* µm synapse-to-soma distance).

Means	Speed	Time	References
Transport vesicles	11–21 µm/hr	2–4 hr	[14]
Transport granules^**	122 µm/hr	20 min	[15]
Diffusion of CaM	D = 2.5×10⁻⁹ cm²/s	48 min	[8]
Diffusion of kinase-bound CaM	D = 5×10⁻⁸ cm²/s	2.7 min	[8]
Regenerative Calcium waves^***	∼0.1 µm/ms	0.4 sec	[16]
Electrotonic signal	81 µm/ms	0.5 ms	^****

*: The distance from the soma to the most proximal spine was reported to be 39.7±12.1 µm [9].

**: Average maximal speed of granules traveling along a dendrite is 0.034±0.025 µm/s [15].

***: Regenerative Calcium waves were ruled out as means for synapse-to-CREB signaling [1].

****: Electrotonic speed (θ) was calculated according to the parameters in Table 2 using the conventional definition Inline graphic given by the classic cable theory.

Table 1. Expected Traveling Time of Different Means of Signaling. (Calculated for 40 µm synapse-to-nucleus distance, which correspond to ∼30* µm synapse-to-soma distance).

Table 1. Expected Traveling Time of Different Means of Signaling. (Calculated for 40 µm synapse-to-nucleus distance, which correspond to ∼30^* µm synapse-to-soma distance).