the basal forebrain
DESCRIPTION
The effect of intrabasalis orexin A infusion on reversal learning performance in rats with 192 IgG-saporin lesions of the nucleus basalis magnocellularis Patrick Piantadosi Mentor: Aileen Bailey, Ph. D. St. Mary’s College of Maryland. The Basal Forebrain. - PowerPoint PPT PresentationTRANSCRIPT
The effect of intrabasalis orexin A infusion on reversal learning performance in rats with 192 IgG-saporin lesions of the nucleus basalis magnocellularis
Patrick Piantadosi
Mentor: Aileen Bailey, Ph. D.
St. Mary’s College of Maryland
The Basal Forebrain
Provides acetylcholine (ACh) to the cortex, amygdala, hippocampus, and olfactory bulb (Mesulam et al., 1983)
Basal forebrain cholinergic system (BFCS)
nBM/SI
BFCS and Alzheimer’s Disease
Alzheimer’s (AD) hallmarks Neuronal death (Ezrin-Waters & Resch, 1989)
nBM/SI degeneration > 75% cholinergic cell death (Whitehouse et al., 1982)
Pre-symptomatic (Hall, Moore, Lopez, Kuller, & Becker, 2008)
Degree of cholinergic damage = correlated with dementia severity ↑ Cell death = ↑ Dementia symptoms (Perry, et
al.,1978)
nBM/SI Functional Importance
Animal “models” of AD Damage to the nBM impairs:
Learning set acquisition (Bailey, Rudisill, Hoof, & Loving, 2003)
Attention (Lehmann, Grottick, Cassel, & Higgins, 2003)
Feature Binding (Botly & De Rosa, 2009)
Reversal learning (Cabrera, Cortez, Corley, Kitto, & Butt, 2006)
nBM is critical for behavioral flexibility
Reversal learning
Acquisition Reversal
Correct choice! Correct choice!
Cues can be from any sensory modality
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Acquisition
No difference between nBM lesioned rats and controls (Cabrera et al., 2006)
Fig. 1, Cabrera et al., 2006
Reversal - Deficit
Animals with nBM lesions perform significantly worse (more errors) than control animals during the first reversal. (Cabrera et al., 2006)
Fig. 3, Cabrera et al., 2006
The Orexins
Two distinct hypothalamic neuropeptides Orexin A (OxA) and Orexin B (OxB)
Orexin projections synapse on cholinergic neurons
Brown = Cholinergic neuron
Black = OxA fibers
Sakurai et al., 2005
OxA to the basal forebrain…
Increased ACh efflux to the cortex
Orexin antagonism impairs feeding latency
Fig. 4, Frederick-Duus, Guyton & Fadel, 2007Fig. 2, Fadel & Frederick-Duus, 2008
Orexins and the Basal Forebrain
nBM lesions = ↓ ACh to the cortex = Impaired reversal learning
Intrabasalis OxA = ↑ ACh efflux in cortex Decrease cholinergic neurons in the nBM
Infuse OxA = What effect on cortical / cholinergic dependent behavior?
Hypothesis
Group # 1 2 3 4
Treatment Sham-Operated + aCSF
Sham-Operated + OxA
nBM Lesion + aCSF
nBM Lesion + OxA
Acqusition Hypothesis No impairment No impairment No impairment No impairment
Reversal Hypothesis No impairment No impairment
Impaired compared to Group 1,2,4
Similar to 1 & 2
Methods
Subjects 24 adult male Sprague
Dawley rats Stereotaxic Surgery
12 animals = 192 IgG-saporin lesions of the nBM (0.2 µl at 0.375 µg/µl)
12 animals = sham surgery Bilateral nBM guide
cannula
Olfactory Discrimination Reversal Learning
Pretraining – 7-8 days Acquisition – 1-2 days
50 trials / day Two olfactory cues
Onion Powder + Sand Garlic Powder + Sand
One scent was rewarded Criterion: 8 correct responses in a row
Without a correction trial Reversal – 1-2 days
50 trials / day Same olfactory cues Reward contingency = reversed Criterion: 8 correct responses in a row
Without a correction trial
Correct choice!Correct choice!
Reversal
Prior to reversal animals were infused with: OxA (n = 12)
250 nl at 0.25 nmol / 2 min
or aCSF (n = 12)
250 nl / 2 min
ODRL Testing
Dependent Measures
Trials to criterion # of trials to reach criterion
Correction trials # of correction trials to reach criterion
Error type Reversal only
Perseverative < 2/10 correct responses
Non-perseverative
Acquisition - Trials to Criterion
No effect of surgical procedure, infusion type, or interaction on trials to criterion during acquisition, all p-values > .05
Lesion Sham0
5
10
15
20
25
30
35
40aCSF
OxA
Surgical Procedure
Acq
uisi
tion
Tria
ls to
Crit
erio
n
Acquisition - Correction Trials
No effect of surgical procedure, infusion type, or interaction on the number of correction trials during acquisition, all p-values > .05
Lesion Sham0
5
10
15
20
25
30 aCSF
OxA
Surgical Procedure
Acq
uisi
tion
Cor
rect
ion
Tria
ls
Reversal – Trials to Criterion
Effect of surgical procedure: F(1,20) = 2.798, p = .11, η2 = .12
No effect of infusion type or interaction, all p-values > .05
Lesion Sham0
10
20
30
40
50
60
aCSFOxA
Surgical Procedure
Rev
ersa
l Tria
ls to
Crit
erio
n
Reversal – Trials to Criterion
Lesion + aCSF animals required more trials to reach criterion during reversal than sham + aCSF animals t(10) = -2.06, p = .07, η2 = 0.30
Lesion Sham0
10
20
30
40
50
60
aCSF
OxA
Surgical Procedure
Rev
ersa
l Tria
ls to
Crit
erio
n
*
Reversal – Correction Trials
Effect of lesion: F(1,19) = 2.876, p = .11 , η2 = .13
No effect of infusion type or interaction, all p-values > .05
Lesion Sham0
20
40
60
80
100
120
aCSFOxA
Surgical Procedure
Rev
ersa
l Cor
rect
ion
Tria
ls
Results - Summary
Group # 1 2 3 4
Treatment Sham-Operated + aCSF
Sham-Operated + OxA
nBM Lesion + aCSF
nBM Lesion + OxA
Acquisition Results No impairment No impairment No impairment No impairment
Reversal Results No impairment No impairment
↑ Trials to criterion
compared to Group 1
No difference compared to Group 1,2,3
Discussion – Surgical Procedure
No robust effect of lesion Why?
High effect size of surgical procedure on: Reversal trials to criterion Reversal correction trials
Nearly significant effect of lesion in aCSF group Reversal trials to criterion
Histology could not be analyzed 192 IgG-SAP lesions do not impair reversal learning?
No difference between nBM lesioned rats and sham-operated controls (Tait & Brown, 2008)
Ibotenic acid infusion to the nBM produced reversal learning deficits (Tait & Brown, 2008)
Discussion – Orexin A
No effect of orexin infusion Why?
Cholinergic neurons may be necessary for orexin-mitigated ACh efflux
OxA + few cholinergic neurons = no behavioral effect Too little OxA infused? Guide cannula too ventral?
Implications
Future research should: Evaluate the impact of OxA on cortical dependent
behavior AD symptom – weight loss
Highly correlated with death (White, Piper, & Schmander, 1998)
Orexins = located in LHA Stimulate feeding behavior (Frederick-Duus, Guyton, & Fadel, 2007)
No cholinergic neurons = no effect of orexin = abnormal feeding behavior?
nBM function Clarify the role of the nBM in reversal learning
Acknowledgements
Special thanks to: Jenn St. Germain Dr. Aileen Bailey Dr. Anne Marie Brady Various neuroscience students!
References Bailey, A.M., Rudisill, M.L., Hoof, E.J., & Loving, M.L. (2003). 192 IgG-saporin lesions to the nucleus basalis magnocellularis (nBM)
disrupt acquisition of learning set formation. Brain Research, 969, 147-159. Botly, L.C.P. & De Rosa, E. (2009). Cholinergic deafferentation of the neocortex using 192 IgG-saporin impairs feature binding in rats.
The Journal of Neuroscience, 29, 4120-4130. Cabrera, S.M., Chavez, C.M., Corley, S.R., Kitto, M.R., Butt, A.E. (2006). Selective lesions of the nucleus basalis magnocellularis impair
cognitive flexibility. Behavioral Neuroscience, 120, 298-306. Ezrin-Waters, C. & Resch, L. (1989). The nucleus basalis of Meynert. The Canadian Journal of Neurological Sciences, 13, 8-14. Fadel, J. & Frederick-Duus, D. (2008). Orexin/hypocretin modulation of the basal forebrain cholinergic system: Insights from in vivo
microdialysis studies. Pharmacology, Biochemistry, and Behavior, 90, 156-162. Frederick-Duus, D., Guyton, M.F., & Fadel, J. (2007). Food elicited increase in cortical acetylcholine release require orexin transmission.
Neuroscience, 149, 499-507. Hall, A.M., Moore, R.Y., Lopez, O.L., Kuller, L., & Becker, J.T. (2008). Basal forebrain atrophy is a presymptomatic marker for Alzheimer’s
disease. Alzheimer’s and Dementia, 4, 271-279. Lehmann, O., Grottick, A.J., Cassell, C., & Higgins, G.A. (2003). A double dissociation between serial reaction time and radial maze
performance in rats subjected to 192 IgG-saporin lesions of the nucleus basalis and/or the septal region. European Journal of Neuroscience, 18, 651-666.
Mesulam, M.M., Mufson, E.J., Wainer, B.H., & Levey, A.I. (1983). Central cholinergic pathways in the rat: An overview based on alternative nomenclature (Ch1-Ch6). Neuroscience, 10, 1185-1201
Perry, E.K., Tomlinson, B.E., Blessed, G., Bergman, K., Gibson, P.H., & Perry, R.H. (1978). Correlation of cholinergic abnormalities with senile plaques and mental test scores in senile dementia. British Medical Journal, 25, 1457-1459.
Sakurai, T., Nagata, R., Yamanaka, A., Kawamura, H., Tsujino, N., Muraki, Y., Kageyama, H., Kunita, S., Takahashi, S., Goto, K., Koyama, Y., Shioda, S., & Yanagisawa, M. (2005). Input of orexin/hypocretin neurons revealed by a genetically encoded tracer in mice. Neuron, 46, 297-308.
Tait, D.S. & Brown, V.J. (2007). Lesions of the basal forebrain impair reversal learning but not shifting of attentional set in rats. Behavioral Brain Research, 187, 100-108
Testing Phase
No effect of surgical procedure, infusion type, or interaction on trials to criterion during acquisition, all p-values > .05
Acquisition Reversal0
10
20
30
40
50
60
Sham+aCSF
Sham + OxA
Lesion + aCSF
Lesion + OxA
Test Phase
Tria
ls to
Crit
erio
n
Reversal – Error Type
No significant effect of lesion type on perseverative errors (p = .17), or non-perseverative errors (p = .77) Error bars = ±SEM
Perseverative Errors Non-perseverative Errors0
5
10
15
20
25
30
ShamLesion
Types of Error
Num
ber o
f Err
ors
Dur
ing
Rev
ersa
l
Histology - AChE
Sham-operated nBM Lesion
Cortical analysis
nBM analysis
Histology – Nissl Staining
Thakkar et al., 2001
Blanco-Centurion et al., 2006
Conclusion
No robust effect of lesion nBM cholinergic neurons not necessary for
reversal learning? Some lesions may not have been effective
No effect of OxA was observed OxA may not impact behavior without cholinergic
neurons Guide cannula too ventral? Amount of OxA too small
192 IgG-saporin Lesion
IgG = monoclonal antibody
Saporin = ribosome inactivation protein
Only binds to cells containing the p75 neurotrophin receptor Cholinergic cell
death
192 IgG-saporin
Cells containing p75 receptors
Dashed lines = cholinergic neurons
Results
No significant surgical procedure x infusion type interactions
All figures display error bars representing ± one SD, unless otherwise specified
2 (surgical procedure) x 2 (infusion type) ANOVA Multiple independent samples t-tests
Acquisition - Correction Trials
Lesion + aCSF animals trended towards requiring greater amount of correction trials, p = .06, η2 = 0.33 (independent samples t-test) No other significant differences, all p-values > .05
Lesion Sham0
5
10
15
20
25
30 aCSF
OxA
Surgical Procedure
Acq
uisi
tion
Cor
rect
ion
Tria
ls
*
Acquisition Summary
No effect of Surgical procedure Infusion type Interaction
Expected nBM lesioned animals = no simple discrimination
deficit No difference between animals to receive
different infusion types