This is some numbers I collected long time ago.
| What | How Much | Where |
| Constants and Equations | (a list) | go to |
| Brain Facts | (a list) | go to |
| Metabolic Energy | (a list) | go to |
| Number of neurons and synapses | ||
| neurons | 1011 | |
| synapses | 1014 | |
| pyramidal neurons | >80% | Attwell and Laughlin 2001 |
| glutamate synapses | >90% | Attwell and Laughlin 2001 |
| ganglion cells in human regina | 1.5 million | de Gelder, et al, Out of Mind, chapter 1 |
| ganglion cells in human regina projected to LGN | 90% of 1.5M | de Gelder, et al, Out of Mind, chapter 1 |
| ganglion cells in human regina projected to superior colliculus | 105 | de Gelder, et al, Out of Mind, chapter 1 |
| Energy | ||
| Energy of one ATP molecule | 25kT | ref |
| Energy of 1 mol ATP molecules (at normal cellular condition, ATP = 10mM, ADP = 0.1mM, Pi = 10mM) |
53327 J 20kT |
homework in integrative neuroscience I, by Paul Pfaffinger |
| Energy taken up by male adult per day | 10^7 J | ref original ref |
| % Oxygen consumption of brain to total | 20% | go to |
| % energy consumed to pumps Na and K, to total brain energy usage |
50% | ref |
| ATP concentration at normal cellular conditions |
10 mM | homework in integrative neuroscience I, by Paul Pfaffinger |
| ADP | 0.1 mM | |
| Pi | 10 mM | |
| Phosphate bond energy at Standard Condition |
7.3kcal/mol 30.5kJ/mol 5.1*10^(-20)J/bond 11.8 kT |
go to |
| Number | ||
| # of calcium ions flow into cell during an AP | 200-13000/active zone/spike | Borst and Sakmann, 1996 |
| # of neurotransmitter in a vesicle | 4000 | Kandel |
| # of vesicles in presynaptic bouton | 1-10 CNS | |
| diameter of a vesicle | 50nm and 70-200nm | |
| PH w/i a vesicle | 5.5 | |
| PH cytoplasm | 7 | |
| # of vesicle released per synaptic transmission |
1 | Levy and Baxter 2002 |
| # of ions transported by a single acetylcholine-activated channel in one second |
10^7 | |
| # of ions transported by Na/K pump per second |
10^3 | |
| Information | ||
| information rate of fully light-adapted photo-receptor cell under random stimuli |
1000 bit/s | ref |
| information rate of LMC | 1600 bit/s | ref |
| synapse between photo-receptor and LMC | 55 bit/s | ref |
| energy per bit of photo-receptor | 7*10^6 ATP/bit | ref |
| energy per bit of LMC | 0.9-3*10^6 ATP/bit | ref |
| energy per bit of chemical synapse | 2-6*10^4 ATP/bit | ref |
| Other | ||
| Biological Membrane Capacitance | 1uF/cm2 | go to |
| Number of Neurons in brain | 10^11 | |
| Number of Synapses in cerebral cortex | 60-240trillion | Brain facts |
| probability to release a vesicle if action potential arrives presynaptically |
0.1-0.5 | go to Laughlin and Sejnowski, 2003 |



The “go to” links on hnl website does not work.
@Mingbo Cai
Will fix it.