Bilateral damage to the mammillothalamic tract impairs recollection but
not familiarity in the recognition
process: A single case investigation
G.A. Carlesimo, L. Serra, L. Fadda,
A. Cherubini, M. Bozzali, C.
Caltagirone
Neuropsychologia 45 (2007) 2467-2479
Presentation by Adam Bregman
Who is this person?
G.P. is a 38 year old right handed
man.
He was a lawyer with a prominent
company in Italy
What went wrong?
While walking, fell unconscious in
February 2001.
Was taken to the hospital where
he regained consciousness a few
hours later with anterograde and
retrograde amnesia.
A few days later he had enduring
problems with anterograde LTM
Neuroanatomy Background Info
MTL injuries- poor episodic
memory with either recall or
recognition. Show normal scores
on STM, semantic, procedural
memory.
Caused by thalamic lesions which is
from disconnection between MTL
structures and anterior thalamus
Background continued
Mammillo-thalamic tract: connects
hippocampus of MTL to mamillary
bodies and the medial and lateral nuclei
of mamillary bodies to anterior thalamic
nuclei, which project to limbic cortical
areas such as cingulate cortex.
VAF pathway: intrathalamic portion of
pathway from amygdala and perirhinal
cortex to MD thalamus.
Diagram of mammillo-thalamic tract
Clinical Connections
 Claim that some structures in MTL involved
in only recall of recent episodic memory,
others in recognition
 Recognition: evidence that perirhinal cortex
in parahippocampal gyrus impt. Receives
input from all sensory areas of brain and is
important in recgonition of episodic memory
 Recall: Hippocampus receives cortical inputs
from parahippocampal gyrus and then
projects to cortical and subcortical regions.
 Aggleton and Brown (1999): damage to MTT
and anterior thalamus cause severe and
selective damage to recall
 Damage to MD to thalamus or VAF, problems
to recognition
What’s the Nature of the
damage
Bilateral thalamic damage.
MRI showed two ischemic lesions in
anterior medial thalamus.
Lesion volumes were 316 and 217mL on
right, and 57 and 22mL on left for two
different scans.
Right thalamic lesion involved MTT
Left thalamic lesion involved MTT and
ventral anterior thalamic nucleus.
MD nucleus spared
MRI of Ischemic Lesions
Aspects of memory impaired
 Battery of neuropsychological tests all normal
with exception of recognition tests compared to
age matched controls
 Problems with block design and object assembly
and object decision subtest.
 Normal STM, immediate memory intact but
delayed episodic is poor
 WAIS IQ=110
 WAIS verbal subtest=133
 Overall: impaired declarative episodic memory
for verbal and visuo-spatial material. Normal
recognition on two choice tests, but poor on
yes/no and multiple choice tests. Preserved
recognition.
Discussion and Implications
Visuo-spatial problems could be due to
larger damage to right hemisphere.
MD nucleus spared, which is important
in recognition
Only damage to MTT, so only problems
with recall.
Hippocampus only: problems with recall
Hippocampus and parahippocampal
gyrus: recall and recognition problems