2. When an axon of cell A is near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased D. Hebb

3. Mediazione rapporti neurone-capillari Regolazione metabolica

4. Regolazione flusso ematico (1)

5. Regolazione flusso ematico (2)

6. Sequestro (regolazione) del mediatore dallo spazio sinaptico

7. Sifonaggio del K +

16. m

21. Diagram illustrating the kinetics of slow axonal transport, as revealed by radioisotopic pulse labelling. A)Radioactive amino acids injected into the vicinity of the neuronal cell body produce a transient pulse of newly synthesized radioactive proteins, which b,c )move together along the axon by axonal transport. After a time interval ranging from hours to months, the animal is killed, the nerve is excised and sliced into segments, and each segment is analysed biochemically to identify the radioactive proteins. The pulse-labelled proteins form an asymmetrical wave (red) that spreads as it moves along the axon.