International Society for Behavioural Neuroscience
17th Annual Meeting, May 27-31, 2009
Hilton Oceanfront Resort, Hilton Head, South Carolina, USA
Kelly Giovanello, Meeting Organizer
Schedule At A Glance
Wed May 27 – 5 pm Welcome Reception: The Courtyard
Thur May 28 8-9 am Continental breakfast
9 am-12:15 pm Traditional Session (coffee break @ 10:30)
12:15-4:30 pm Lunch and free time
4:30-6 pm Group Social Activity followed by Dinner
Friday May 29
8-9 am Continental breakfast
9 am-12:30 pm Symposium: Advances in Understanding Cognitive Aging (Gutchess and Kensinger) with coffee break @ 10:30
12:30-1:30 pm Lunch
1:30 pm Presidential Speaker: Professor Lynn Nadel
“Hippocampus: Context and Memory”
3:00-4:30 pm Business Meeting (current members only)
6:30 pm Banquet Dinner (at hotel)
Saturday May 30
8-9 am Continental breakfast
9 am-12:30 pm Symposium: Advances in Understanding Neural
Contributions to Associative Memory (Addis and Giovanello)
(coffee break @ 10:30)
12:30 pm Group Excursion
Sunday May 3
9-10 am Traditional Session (coffee break @10:00)
10:15-11:15 am Works in Progress
11:30 am Farewell Lunch at Resort
All scientific sessions are in Promenade 4.
Abstracts
Traditional Paper Session (Thursday May 28)
Florin Dolcos1, Rajendra Morey2, Roberto Cabeza3, Gregory McCarthy4
1Department of Psychiatry, University of Alberta, Edmonton, AB, Canada, 2Department of Psychiatry, Duke University, Durham, NC, USA, 3Center for Cognitive Neuroscience, Duke University, Durham, NC, USA, 4Department of Psychology, Yale University, New Haven, CT, USA
“Neural signatures of the response to emotional challenge: brain imaging evidence from healthy and clinical groups”
Although increased susceptibility to emotional distraction is a debilitating feature of affective disorders, little is known about the neural circuitry sensitive to individual differences in the response to emotional challenge. We investigated this issue in both healthy and clinical groups, using brain imaging and behavioral tools. Functional MRI data were acquired while subjects performed working memory (WM) tasks with emotional distraction. Behavioral data indexing patterns of response in affective and cognitive domains were recorded using tools that assessed both general (e.g., attentional) and specific (e.g., emotional) aspects of processing. Behavioral data showed that healthy subjects with increased susceptibility to task-irrelevant emotional distraction also had enhanced attentional impulsivity and emotional arousability scores. Brain imaging data linked these behavioral differences to opposing patterns of activity in the amygdala (enhanced) and dorsolateral prefrontal cortex (decreased), consistent with the role of these regions in emotion detection and cognitive control, respectively. Similar investigation in participants with posttraumatic stress disorder showed overall exacerbated response to emotional distraction, consistent with increased emotional distractibility and impaired cognitive control in these patients. Collectively, these findings identify specific neural signatures of the response to emotional challenge, which may be used as neurobiological markers to enhance diagnostic accuracy and treatment efficacy.
Audrey Duarte
School of Psychology, Georgia Institute of Technology
“Domain general and domain specific recollection: MTL and beyond”
Numerous neuroimaging studies have implicated the medial temporal lobe (MTL), in particular the hippocampus and parahippocampus, in the recollection of contextual associations, across various types of materials and associations. Although the MTL may contribute to recollection in a domain-general fashion, some neuroimaging and lesion evidence suggests that the MTL may process information in a material-specific fashion. It is yet unkown whether recollection effects within the MTL, and beyond, are material specific. In this fMRI study, activity predictive of subsequent recollection for an encoded context was compared for objects, scenes and words. Although anterior and posterior MTL exhibited material specific effects for objects and scenes, respectively, scene-specific recollection effects were identified in the posterior MTL only. Regions outside of the MTL (e.g. inferior frontal gyrus, lateral occipital cortex) exhibited recollection effects that were material specific. The hippocampus contributed to recollection equally for all materials. These data provide support for the hypothesis that while the hippocampus contributes to recollection in a domain general fashion, posterior MTL is more sensitive to nature of the central stimulus and/or contextual associations. Although anterior and posterior MTL may differentially contribute to perceptual processing of stimuli, this dissociation does not necessarily extend to recollection.
Morgan Barense
Department of Psychology, University of Toronto
“The gray area between memory and perception in the ventral visual stream: Insights from neuroimaging and neuropsychology”
Amnesia resulting from medial temporal lobe lesions is traditionally considered to be a selective deficit in long-term declarative memory. Here, I challenge this view with data from studies that indicate that high-level perceptual processing – or very short-term visual working memory – may also be compromised in the disorder. These results, combined with convergent evidence from fMRI, suggest that neural circuits in the medial temporal lobe are involved in both memory and perception, contrary to theories that posit functional and neuroanatomical segregation of these processes.
Charlie Wilson
Department of Experimental Psychology, Oxford University
“Prefrontal-inferotemporal interaction is not always necessary for reversal learning; the benefit of understanding the role of cortical interactions”
Crossed unilateral ablations, which disconnect cortical areas, enable us to study the critical role of the interaction between those areas independent of the specific functions of the areas when isolated. Given the increasing focus within neuroscience upon widespread network interactions, this is a powerful and relevant technique. Disconnection of prefrontal cortex (PFC) and inferotemporal cortex (IT) produces strikingly different effects on different visual learning tasks in the macaque monkey (Gaffan et al 2002; Browning et al 2007). We sought to understand the role of this interaction more clearly using two visual object reversal learning paradigms which might be expected to rely on object processing in IT, and inhibition of representations in a “top-down” manner by PFC. We therefore tested whether PFC directly inhibits visual object representations in IT during reversal learning. We found that the PFC x IT disconnection severely impairs serial reversal learning, but leaves concurrent reversal learning completely intact. Thus, PFC cannot be said to always have direct inhibitory control over visual object representations in reversal learning. Furthermore, our results cannot be explained by generalized theories of PFC function such as executive function and behavioural inhibition, because those theories do not make predictions that differentiate different forms of reversal learning. We are now extending the disconnection technique to investigate the role of the interaction between PFC and posterior parietal cortex, in order to understand whether the findings relating to PFC-IT interaction can be generalized to all PFC function.
Mark Baxter
Department of Experimental Psychology, Oxford University
“Functional recovery following structural damage to brain circuits for memory requires cortical cholinergic input”
Memory depends on a network of interconnected brain structures. Damage to either the fornix or mammillary bodies causes amnesia in both humans and nonhuman primates. We have found that the severity of amnesia after damage to either of these structures is modulated by prior loss of cholinergic projections to the inferotemporal cortex, the cortical region through which visual information reaches structures important for memory. Macaque monkeys with cholinergic depletion of inferotemporal cortex were unimpaired at learning new object-in-place scene problems. However, these monkeys were substantially more impaired following lesions of the fornix or mammillary bodies than were monkeys with intact temporal cortical cholinergic input. Reversing the order of the lesions did not produce severe amnesia, indicating that the presence of cholinergic projections to temporal cortex at the time of fornix or mammillary body damage enables recovery. Humans with loss of cholinergic function may be less able to adapt to the impairments caused by neuronal loss within cortical and subcortical structures important for memory.
Paula Croxson
Department of Experimental Psychology, Oxford University
“The effect of multiple neuromodulator depletion on episodic memory in monkeys”
Recent work from our laboratory and others has suggested that acetylcholine may play an important role in some aspects of cognitive function, and in particular in episodic memory. However, the role of other neuromodulatory (NM) substances, such as noradrenaline, dopamine, and serotonin, in episodic memory is less well-defined. We tested monkeys on object-in-place scene learning, a model of episodic memory in monkeys and carried out specific depletions of different neuromodulators within inferotemporal cortex (IT). Five male rhesus monkeys were trained on an object-in-place scene learning task that, because learning occurs rapidly (mostly in a single trial) and depends on the presentation of discrimination problems in unique background scenes, models key features of human episodic memory. After preoperative testing three monkeys were given injections into IT of the immunotoxin ME20.4-saporin interleaved with injections of 6-hydroxydopamine and 5,7-dihydroxytryptamine. This resulted in depletion of acetylcholine, dopamine, noradrenaline and serotonin throughout IT (group NM+ACh). Two monkeys received the same treatment but omitting the ME20.4 saporin, thus depleting dopamine, noradrenaline and serotonin, but sparing acetylcholine (group NM). Neither group of monkeys (NM+ACh or NM) were impaired in postoperative scene learning. We found previously that addition of fornix transection to depletion of ACh from IT severely impaired scene learning relative to fornix transection alone (Browning et al. 2009, Cerebral Cortex). Therefore we gave each monkey in groups NM and NM+ACh a bilateral fornix transection and performed a further postoperative performance test. As expected, monkeys in group NM+ACh were severely impaired in scene learning following fornix transection. However, monkeys in group NM were also severely impaired in scene learning following fornix transection, despite having no visible damage to cholinergic innervation. Depletion of cholinergic, dopaminergic, adrenergic and serotoninergic innervation of inferotemporal cortex, therefore, is not sufficient to impair monkeys’ performance on an episodic memory task. Furthermore, there is a synergistic interaction between the NM depletion and fornix transection in this task, like that between ACh depletion and fornix transection. This may be due to a general reduction in cortical function after NM depletion, albeit not sufficient to cause episodic memory impairment on its own, which exacerbates the effect of fornix transection. It may point to one or more of these neuromodulators having a role in post-lesion plasticity, a role that is also played by ACh. Importantly, these data suggest that intact cholinergic innervation is not sufficient for post-lesion plasticity.
Symposium: Advances in Understanding Cognitive Aging (Friday, May 29)
Scott Huettel
Department of Psychology and Neuroscience, Brain Imaging and Analysis Center, and Center for Cognitive Neuroscience, Duke University
“Decision making and cognitive aging: Why (bother with) neuroeconomics?”
Decision-making processes change over the lifespan. Across a wide variety of contexts, older adults tend to exhibit a number of decision biases: impaired use of feedback information, misestimation of probabilities, and imperfect valuation of outcomes, among others. These decision biases lead to demonstrably inefficient decisions in real-world settings (e.g., interest rates, investment fees, portfolio balancing), with attendant consequences for society. Yet, despite substantial interest in these biases within both the economics and cognitive psychology communities, there has been little integration of behavioral data – and even less research on the underlying neural mechanisms. My talk will consider both practical and theoretical issues related to the development of a neuroeconomics of aging. One theme will introduce the concepts that underlie current neuroeconomic research, few of which have been extended to older adult populations. Data will include recent studies from our laboratory that demonstrate that key decision biases of older adults, in both laboratory and real-world measures, can be attributed to specific aspects of age-related cognitive decline. A second theme will consider the relevance of a “neuroeconomics of aging” – and whether and how these disparate and complex fields should be combined.
Kelly Giovanello, Wei-chun Wang, William E. Moore, and Ilana T. Z. Dew
Department of Psychology and Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill
“Neural Correlates of Implicit Relational Memory in Young and Older Adults”
Whereas item memory provides the basis for remembering that a stimulus or event has occurred, relational memory represents the relationships between items or informational elements. Both item and relational memory can be tested explicitly in which participants are intentionally instructed to recognize stimuli from a previous encoding phase (e.g., recognition), or can be tested implicitly in which no reference is made to a prior encoding episode (e.g., priming). Previous findings from our laboratory indicate that the hippocampal formation – a structure within the medial temporal lobe – makes a greater contribution to relational memory than to item memory under explicit retrieval conditions, and such hippocampal specificity for relational memory is reduced in healthy aging. In the current study we tested two hypothesis: (1) that the hippocampus makes a greater contribution to relational memory than to item memory under implicit retrieval conditions in young adults and (2) that older adults demonstrate reduced hippocampal specificity even under implicit testing conditions. Twenty-two individuals (12 young) participated in the study. Each individual was scanned in four consecutive event-related functional MRI runs. The first two runs comprised the perceptual priming tasks and the second two runs consisted of the recognition tasks. Behavioral results showed significant perceptual priming and reliable recognition performance in both age groups. Analysis of the neuroimaging data revealed greater bilateral hippocampal activity during implicit relational priming than during implicit item priming, and that older adults recruited extrahippocampal cortices (i.e., parahippocampal gyrus) during implicit relational retrieval. These results are consistent with cognitive neuroscientific theories positing a critical role for the hippocampus in mnemonic processing of relational information, as well as previously documented neural changes in aging.
Kristen Kennedy
Center for BrainHealth, School of Behavioral and Brain Science, The University of Texas at Dallas
“How age-related changes to brain structure impact cognitive aging”
The aging brain undergoes numerous changes to its structure, and many of these changes can be examined using Magnetic Resonance Imaging (MRI) methods. This talk will summarize age-associated changes to regional brain volumes, white matter hyperintensity (WMH) burden, and microstructural integrity of the white matter (using Diffusion Tensor Imaging; DTI). How these methods to gauge changes in the aging brain have been used to understand aging of different aspects of cognition will be discussed.  Â
Elizabeth Kensinger
Department of Psychology, Boston College
“Aging, emotion, and memory”
We tend to remember emotional experiences long after we have forgotten more mundane ones.  In this talk, I will describe how aging affects the ability to remember emotional experiences. More specifically, I will discuss how emotion’s ability to influence how we encode, consolidate, and retrieve information may change as we age. I will put particular emphasis on examining the role of the amygdala in emotional memory, describing how the amygdala exerts its effects via interactions with other sensory and mnemonic regions, and I will discuss the extent to which these amygdala interactions are preserved with aging.
Symposium: Advances in Understanding Neural Contributions to Associative Memory (Saturday, May 30)
Donna Addis1 and Kelly Giovanello2
1Department of Psychology, The University of Auckland; 2Department of Psychology and Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill
“Age-Related Changes in Associative Memory”
The ability to encode associative information declines with advancing age. However, it remains unclear whether this deficit reflects changes in the functioning of prefrontal cortex and/or medial temporal lobes. We investigated this question using a subsequent memory paradigm for word triads. Critically, we varied the number of words within the triads that were semantically related. This enabled us to tease apart the contribution of inferior frontal gyrus (IFG) to the generation of semantic associations to link the three words (generative load), and the hippocampus to the binding of semantic associations that are already provided (associative load). Young adults exhibit increasing IFG activation in response to increasing generative load, and increasing hippocampal activation in response to associative load. In older adults, we found the IFG did not modulate significantly in response to increasing generative load. However, the hippocampus did respond to associative load, suggesting that when provided with associations to bind, hippocampal activity in older adults is comparable to young.
Scott Hayes
Center for Cognitive Neuroscience, Joseph and Kathleen Bryan Alzheimer’s Disease Research Center, Duke University and Duke University Medical Center
“Neural Mechanisms of Context Effects on Face Recognition: Automatic Binding and Context Shift Decrements”
Although people do not normally try to remember associations between faces and physical contexts, these associations are established automatically, as indicated by the difficulty of recognizing familiar faces in different contexts (“butcher-on-the-bus” phenomenon). The present functional MRI (fMRI) study investigated the automatic binding of faces and scenes. In the Face-Face (F-F) condition, faces were presented alone during both encoding and retrieval, whereas in the Face/Scene-Face (FS-F) condition, they were presented overlaid on scenes during encoding but alone during retrieval (context change). Although participants were instructed to focus only on the faces during both encoding and retrieval, recognition performance was worse in the FS-F than the F-F condition (“context shift decrement”-CSD), confirming automatic face-scene binding during encoding. This binding was mediated by the hippocampus as indicated by greater subsequent memory effects (remembered > forgotten) in this region for the FS-F than the F-F condition. Scene memory was mediated by the right parahippocampal cortex, which was reactivated during successful retrieval when the faces were associated with a scene during encoding (FS-F condition). Analyses using the CSD as a regressor yielded a clear hemispheric asymmetry in medial temporal lobe activity during encoding: left hippocampal/parahippocampal activity was associated with a smaller CSD, indicating more flexible memory representations immune to context changes, whereas right hippocampal/parahippocampal activity was associated with a larger CSD, indicating less flexible representations sensitive to context change. Taken together, the results clarify the neural mechanisms of context effects on face recognition.
Alison Preston
Center for Learning and Memory and Department of Psychology, The University of Texas at Austin
“Medial Temporal Lobe Contributions to Rapid Acquisition and Flexible Transfer of Associative Information”
Flexibility is needed when elements of individual experiences must be combined in new ways to deal with novel situations. This flexibility is a powerful characteristic of declarative memory because it allows for the generative use of the rapidly acquired experiences to address new questions posed by the environment. Fundamental questions remain regarding the cognitive and neural mechanisms that support successful generalization. Such generalization may stem from inferential processing at the time of generalization or result from integrative encoding process during the time of initial learning. The associative inference paradigm provides a means to investigate the neural basis for generalization in declarative memory by requiring participants to learn overlapping associations in a single trial. Generalization is subsequently probed with novel stimulus combinations that require flexible transfer of learned associations. Utilizing both standard and high-resolution fMRI, we demonstrate activation in hippocampal subregions during encoding that predicts later generalization performance both within and across participants. During flexible transfer, we further identified hippocampal regions distinct from those at encoding whose activation differed based on correct generalization performance. These findings suggest that flexible generalization of rapidly acquired experience depends on integrative encoding and inferential processes during retrieval that are supported by hippocampal processing.
Melanie Cohn1,2, Mary Pat McAndrews1,2, Morris Moscovitch2, 3
1Krembil Neuroscience Centre, University Health Network; 2Department of Psychology, University of Toronto; 3Rotman Research Institute and Department of Psychology, Baycrest Centre for Geriatric Care
“Associative reinstatement and the medial temporal lobes”
Associative memory requires relational binding operations subserved by the medial temporal lobes (MTL). However, several associative memory tasks also require the instantiation of executive post-retrieval operations thought to depend on frontal regions. I will argue that associative reinstatement, which represents the gain in item memory when the studied associative information is reinstated at retrieval, does not and represents a ‘purer’ index of MTL function. To support this, I will present behavioural evidence with healthy young adults under various experimental conditions, older participants and patients with MTL lesions. I will also present results from an fMRI study, which shows that reinstating associative information often engages the hippocampus, and such involvement translates into a contextually-rich, recollective experience.
Traditional Paper Session (Sunday, May 31)
John Desmond1, Matthew P. Kirschen2,3, S.H. Annabel Chen4,5
1Department of Neurology, Johns Hopkins University; 2Department of Radiology and 3Neurosciences Program, Stanford University School of Medicine; 4Department and Graduate Institute of Psychology, National Taiwan University; 5Division of Psychology, Nanyang Technological University, Singapore
“Left inferior cerebellar involvement in verbal working memory as revealed by patient and neuroimaging investigations”
Previous investigations of cerebro-cerebellar circuits underlying verbal working memory have suggested that right superior cerebellar regions contribute to articulatory control processes whereas right inferior cerebellar regions are associated with phonological storage. These findings were largely based on experiments using visually presented letters. Here we report a convergence of patient and neuroimaging data suggesting the importance of left inferior cerebellar regions in the processing of aurally-presented stimuli.  Verbal working memory tasks were administered to children following surgical resection of cerebellar pilocytic astrocytomas, and anatomical MRI scans were used to quantify the extent of cerebellar lobular damage from each patient’s resection. Patients exhibited significantly reduced digit span for auditory but not visual stimuli, relative to controls, and damage to left hemispheral lobule VIII was significantly correlated with this deficit.  These findings are consistent with our recent functional MRI results showing modality-dependent differences in verbal working memory activation. These studies have revealed that left inferior cerebellar activation is considerably more prominent for aurally-presented stimuli than for visually-presented stimuli. In addition, a lateral to medial progression of activation was observed for visual vs. auditory presentation. Similar lateral-to-medial progressions have been observed for motor-related cerebellar activations, and the possible parallels with our results will be discussed.
Eric H. Schumacher1, Keith L. Main1, Julie Jacko2, Susan Primo3, Kevin Moloney1, Erin Kinzel1, Temi Adelore1
1Georgia Institute of Technology; 2University of Minnesota; 3Emory University Medical School
“Cortical and Cognitive Plasticity in Patients with Macular Degeneration”
Research with non-human primates suggests that deafferentation of visual pathways can result in reorganization of the primary visual cortex. Under some circumstances, neurons in the disconnected cortex may begin to respond to stimulation outside their original receptive field. It is controversial whether this kind of reorganization occurs in humans with naturally occurring retinal lesions. We investigated this question using patients with macular degeneration, an eye disease that leads to the progressive loss of foveal and macular vision. We found that cortical reorganization in primary visual cortex is related to the patients’ use of a preferred retinal location (i.e., a spared peripheral retinal area used to fixate after the macular damage). In addition to changes in striate cortex, reorganization may extend to extrastriate visual processing areas as well. Connections between striate and extrastriate cortices may allow changes in the organization of striate cortex to subsequently affect extrastriate areas that mediate attention. We investigated this in two behavioral and fMRI visual attention experiments. Results show that both early visual and higher-order visual attention processes reorganize and adapt in the presence of retinal disease.