***OLFACTION
Archives of Geron
Volume 37, Issue 2 ,
September-October 2003, Pages 119-130
Olfactory identification in elderly Greek people in
relation to memory and attention measures
Alexandra Economou
The
University of Pennsylvania Smell Identification Test
(UPSIT) and the Cross-Cultural Smell Identification Test (CC-SIT) were
administered to nondemented Greek participants ranging in age from 49 to 88
years together with tests of verbal memory from the Wechsler Memory Scale-3rd
Edition (WMS-III). The test scores of the sample administered the CC-SIT were
compared with the test scores of the 12 analogous UPSIT items of the sample
administered the UPSIT. The percent of individuals correctly identifying each
of the odorants of the UPSIT and CC-SIT is reported, together with means and
standard deviations (S.D.) of the total smell scores. UPSIT performance in both
the full test and the 12 analogous items was associated with WMS-III Logical
Memory I performance after accounting for the effects of age, education and
gender. CC-SIT performance was associated with gender, score on the Beck
Depression Inventory-II and Logical Memory I performance. The study shows
that olfactory identification is associated with verbal memory in nondemented
individuals after accounting for demographic variables.
Neurobiology of Aging
Volume 24, Issue 5 , September
2003, Pages 663-673
3-Nitrotyrosine immunoreactivity in olfactory receptor
neurons of patients with Alzheimer's disease: implications
for impaired odor sensitivity
M. L. Getchell, D. S. Shaha, S. K. Buch, D. G. Davis and
T. V. Getchell
Olfactory
sensory function is impaired in patients with the diagnosis of probable
Alzheimer's disease (AD) compared to elderly controls, and the olfactory epithelium
(OE) of AD patients exhibits several pathological changes characteristic of the
AD brain. To confirm that the populations from whom our postmortem tissues are
obtained exhibit similar decrements in sensory function, threshold testing was
performed; probable AD patients had significantly higher olfactory thresholds
than controls. To determine if oxidative stress contributes to decreased
olfactory function in AD, we localized 3-nitrotyrosine (3-NT) immunoreactivity
in OE obtained postmortem from patients with neuropathologically confirmed AD
and age-matched controls with brains free of significant neurodegenerative
pathology. In AD patients, immunoreactivity was localized in olfactory receptor
neurons (ORNs), including dendritic knobs where ion channels that participate
in sensory transduction are located, suggesting a direct mechanism for
olfactory impairment. In controls, immunoreactivity occurred in blood vessel
endothelium, suggesting age-related vascular dysfunction. Immunohistochemistry
for CD68, a macrophage scavenger receptor, demonstrated activated macrophages,
a source of free radicals contributing to 3-NT formation, in the OE of AD
patients but not controls. These results demonstrate increased oxidative
stress and modification of ORN proteins that may contribute directly to
olfactory impairment in AD patients.
NeuroImage
Article in Press, Corrected Proof - Note to users
The cerebellum and olfaction in the aging brain: a
functional magnetic resonance imaging study
Sally Ferdona and Claire Murphy, ,
a, b
The
present study investigated activation of distinct cerebellar regions as a
result of olfactory stimulation in healthy young and elderly adults using
functional magnetic resonance imaging (fMRI). Ten young and 10 elderly adults
were imaged using a 1.5-TMR scanner. The odorant amyl acetate was delivered in
12-s on, 40-s off cycles. Throughout the scan participants responded with a
button press at first detection of each stimulus interval followed by a second
button press upon odorant extinction. Images were processed with AFNI software.
Elderly participants showed significantly decreased cerebellar activation in
both the superior semilunar lobule (Crus I) and the inferior semilunar lobule
(Crus II), two of three previously identified regions of interest for odor
processing, compared to young adults. Interestingly, both groups showed similar
levels of activation in the third region of interest, the posterior
quadrangular lobule (VI), although the elderly showed more variability than the
young did. Previous research identifying this area to be involved in
attention may reflect the possibility that elderly adults engaged in olfactory
tasks may show more variability than young participants in the degree of
attentional demands needed for these tasks as a result of decreased olfactory
abilities.
NeuroImage
Article in Press, Corrected Proof - Note to users
Functional brain imaging of olfactory processing in
monkeys
J. M. Boyett-Andersona, D. M. Lyonsa, A. L. Reissa, b, c,
A. F. Schatzberga, c and V. Menon, , a, b, c
As a step
toward bridging the gap between human and animal studies of olfactory brain
systems, we report results from an fMRI study of olfaction in squirrel monkeys.
High-resolution fMRI images at 3 T with 1.25 × 1.25 × 1.2 mm3 voxels were
obtained covering the whole brain using an 8-cm-diameter birdcage coil and a
gradient–echo spiral pulse sequence. Data were acquired from six sedated adult
males using a standard block design. All fMRI data were spatially normalized to
a common template and analyzed at the individual and group levels with
statistical parametric and nonparametric methods.
Neuropsychopharmacology (2002) 26 27-39.
Tracking the Cognitive Pharmacodynamics of Psychoactive
Substances with Combinations of Behavioral and Neurophysiological Measures
Alan Gevins DSc, Michael E Smith
Ph.D and Linda K McEvoy Ph.D; alan@eeg.com
Many
common pharmacological treatments have effects on cognitive ability.
Psychometric task batteries used to characterize such effects do not provide
direct information about treatment-related changes in brain function. Since
overt task performance reflects motivation and effort as well as ability,
behavioral measures alone may overestimate or underestimate the impact of a
pharmacological intervention on brain function. Here we present a method that
combines behavioral and neurophysiological measures in an attempt to detect the
psychoactive effects of pharmacological treatments with greater sensitivity
than that provided by behavioral measures alone. Initial application of the
method is made to the data from a double blind, placebo-controlled, crossover
study in which caffeine, diphenhydramine, and alcohol were used to alter the
mental state of 16 healthy subjects at rest and while they performed low load
and high load versions of a working memory task. For each intervention, more
sensitive detection of drug or alcohol effects over a four hour period was
obtained when EEG variables were included in multivariate analyses than when
only behavioral variables were used. These initial results suggest that it
can be useful to incorporate neurophysiological measures of brain activity into
inferences concerning the acute impact of drugs on mental function, and
demonstrate the feasibility of using multivariate combinations of behavioral
and neurophysiological measures to sensitively characterize the
pharmacodynamics of drug-induced changes in cognition.
Neuron, Vol 39, 991-1004,
Intensity versus Identity Coding in an Olfactory System
Mark Stopfer, Vivek Jayaraman, and Gilles Laurent * laurentg@caltech.edu
We examined the encoding and decoding of odor identity and
intensity by neurons in the antennal lobe and the mushroom body, first and
second relays, respectively, of the locust olfactory system. Increased odor
concentration led to changes in the firing patterns of individual antennal lobe
projection neurons (PNs), similar to those caused by changes in odor identity,
thus potentially confounding representations for identity and concentration. However,
when these time-varying responses were examined across many PNs,
concentration-specific patterns clustered by identity, resolving the apparent
confound. This is because PN ensemble representations changed relatively
continuously over a range of concentrations of each odorant. The PNs' targets
in the mushroom body—Kenyon cells (KCs)—had sparse identity-specific responses
with diverse degrees of concentration invariance. The tuning of KCs to identity
and concentration and the patterning of their responses are consistent with
piecewise decoding of their PN inputs over oscillation-cycle length epochs.
Psychiatry Research
Volume 120, Issue 2 ,
A brief smell identification test discriminates between
deficit and non-deficit schizophrenia
Nora Goudsmit, , a, Eliza Colemanb, Regine Anna
Seckingera, Rachel Wolitzkya, Arielle D. Stanforda, Cheryl Corcorana, Raymond
R. Goetza and Dolores Malaspinaa
Evidence
is accumulating that smell identification deficits (SID) and social dysfunction
in schizophrenia may share a common pathophysiology. While most schizophrenia
studies utilize the lengthy 40-item University of Pennsylvania Smell
Identification Test (UPSIT) to assess smell identification ability, a brief
12-item smell identification test (B-SIT) has recently been constructed as a
culturally neutral substitute for the UPSIT. By selecting the 12 items of the
UPSIT from which the B-SIT was originally derived, we constructed a proxy for
the B-SIT and compared the performance of 83 patients with schizophrenia to 69
normal subjects. We examined select properties of the B-SIT proxy in relation
to the UPSIT to determine its efficacy for use in psychiatric populations. We
considered the sensitivity of the B-SIT proxy and evaluated a cutoff score for
identifying deficit syndrome schizophrenia (DS). The UPSIT and B-SIT proxy were
significantly related in the patients (n=83, r=0.85, P=0.01) and in comparison
subjects (n=69, r=0.83, P=0.01), and both measures similarly distinguished DS
from non-deficit syndrome (non-DS) patients. The results of this study
support the utility of the B-SIT for schizophrenia research and highlight the
robustness of the relationship between SID and social dysfunction in
schizophrenia.
Decrements in Volume of Anterior Ventromedial Temporal
Lobe and Olfactory Dysfunction in Schizophrenia
Bruce I. Turetsky, MD; Paul J. Moberg, PhD; David R.
Roalf, BA; Steven E. Arnold, MD; Raquel E. Gur, MD, PhD
Arch Gen Psychiatry. 2003;60:1193-1200.
Context Patients with
schizophrenia exhibit olfactory deficits, but it is unclear whether these
represent a specific abnormality. The link between olfactory impairments and
regional brain abnormalities has yet to be established. Objectives
To determine whether patients with schizophrenia exhibit volumetric
deficits in the anterior ventromedial temporal lobe, the target for neuronal
inputs from the olfactory bulb, and whether these are related to olfactory
performance deficits. Design A cohort study of patients and healthy
control subjects who underwent both 1-mm spoiled-gradient echo magnetic
resonance imaging and behavioral tests of olfaction and memory.
Clinical Neuroscience Research
Volume 3, Issues 4-5 , December
2003, Pages 253-262
A review of the relevance and validity of olfactory
bulbectomy as a model of depression
Andrew Harkin, , John P. Kelly
and Brian E. Leonard
Development of valid animal models for human affective disorder.
Attempts have involved numerous approaches such as the exploitation of
vulnerability factors for depression including maternal deprivation, exposure
to psychophysiological stress or by pharmacological depletion of monoamines. However,
no approach is perhaps so radical as the removal of a
part of the brain as occurs in the olfactory bulbectomy (