Study Brain 77

On left, the hippocampus has reconstructed as orderly detours. This slide shows the alveus making a medial detour around the cut. Right side shows intact brain.

This interesting brain was done early in the experiments (1972). The projecting arms of the lowered U-device, which had been hand-held in capsule forceps firmly but lightly, lowered to the ventral skull and gently released, were then cut with stitch scissors. Evidence that it was moved then is the additional scar ventrally. Yes, the device slipped medially but I can see now that the MFB profusely healed across the cut, and the Cx new pattern is in register with the SM and HC abnormalities. There are many goodies!

45 degree anterolateral cut made by lowering a device through the in HT which then slipped caudomedially, giving an extra lateral incision that is now occupied by newly grown MFB. The cut was with a U device. Its arm spacing is 45 div (Olympus) wide most ventrally and also at the SMD levet where the arms are located at 12A0L and 40A, 37L. In the Cx it is 30 div wide, with arms between 36 and 30L.

The midbrain makes a detour, and so does the Fornix (furtively); the cut medial forebrain next to the Fornix is now re-grown, with signs of neoformation and thick fasciculi. Forel’s field makes a lateral detour of black axons into tvm; an opposite detour on the other side of the cut seems to re-connect central medial nucleus. The thalamus is reorganized and there is some crossing but a lot of bypassing. The anterior thalamus has become a cavity, but in places it is crossed by thick wavy axons maybe from the cortex (or to the cortex?) The stria medullaris gives evidence of an additional cut where some of its axons have re-connected across the lesion. There is an apparent scar in the HC in register with the SM neoformation evidence (314). Maybe more granule cells in lesioned dentate gyrus – maybe many more. The cortex in register with these change has a new pattern.

Detail of the same detour. Note undulating neurons.

In the stria medullaris, HC and cortex there is evidence of lesion extending to near the midline and new growth;: the stria medullaris shows signs of axon fusion, the HC shows the bordering-axon-population bulge into the scar that I now believe represents their process of interacting with the scar cells and abolishing the scar creatively, and the cortex has a somewhat orderly new pattern. Moreover axons of the Fornix, cut beyond its lateral border, turn at 90 degrees lateral to grow around the cut. Dorsal to that the MFB, black-axonned, has dense bundles which now can be seen to vigorously pass through the scar cell population! Even more dorsally the H1 with black axons terminates in ventromedial thalamus, as it should. In the thalamus there are crossing and oppositely detouring populations. Every cut tract healed except the MTT.