Trisynaptic Circuit

Hippocampal-Cortical Circuitry

                                                               

AMNESIA……

…………..NOT A SOAP OPERA

Table 2.   Anterograde memory test performance

E. P. Control means (n = 8)

Two-choice recognition   memory

  Words (50) 24 48.4

  Faces (50) 28 41.9

Complex design

  Copy (36) 27 30.3

  Recall (36) 0 20.6

Paired-associate learning

  Trial 1 (10) 0 6.0

  Trial 2 (10) 0 7.6

  Trial 3 (10) 0 8.9

Prose recall

  No delay (21) 3 7.6

  Delay (21) 0 6.4

The mean scores for control subjects for these tests are from Squire and Shimamura (1986). The two-choice recognition memory scores are based on a 24 hr recognition test of 50 words or 50 faces (modified from Warrington, 1984; maximum score, 50; chance, 25). The complex design test score is based on the copy and delayed (12 min) reproduction of the Rey-Osterrieth figure (Osterrieth, 1944; maximum score, 36; see also Figure 6). The paired-associates scores are the number of word pairs recalled on three successive trials (maximum score, 10/trial). The Prose recall scores are based on the number of segments recalled from a short prose passage that was read to the subjects. Recall was tested immediately and after 12 min. Note that the no-delay test requires recall of more information than can be retained in immediate memory, and amnesic patients often obtain impaired scores on this test.

Hypoxia; hippocampus: Another area of selective vulnerability is the hippocampus. In this slide the hippocampus is shrunken, cavitated and discolored, the result of a severe episode of hypoxia.

• Next Slide will show a damaged hippocampus…..

Korsakoff’s Syndrome –Degeneration of Mammillary Bodies

Recall of famous faces

QuickTime™ and aPhoto - JPEG decompressor

are needed to see this picture.

Basal Ganglia

Rat hippocampus

Hippocampal place field

‘Cognitive Map’ Dostrovsky & O’Keefe (1971)

Frontal Cortex

Prefrontal cortex neurons(Working memory)

Hippocampal & subicular recording

DNMS- neural recordings

Hampson & Deadwyler, 2003