The very same thing: Extending the object token concept to incorporate causal constraints on individual identity

The contributions of feature recognition, object categorization, and recollection of episodic memories to the re-identification of a perceived object as the very same thing encountered in a previous perceptual episode are well understood in terms of both cognitive-behavioral phenomenology and neurofunctional implementation. Human beings do not, however, rely solely on features and context to re-identify individuals; in the presence of featural change and similarly-featured distractors, people routinely employ causal constraints to establish object identities. Based on available cognitive and neurofunctional data, the standard object-token based model of individual re-identification is extended to incorporate the construction of unobserved and hence fictive causal histories (FCHs) of observed objects by the pre-motor action planning system. Cognitive-behavioral and implementation-level predictions of this extended model and methods for testing them are outlined. It is suggested that functional deficits in the construction of FCHs are associated with clinical outcomes in both Autism Spectrum Disorders and later-stage stage Alzheimer's disease.\u

Early Category-Specific Cortical Activation Revealed by Visual Stimulus Inversion

Visual categorization may already start within the first 100-ms after stimulus onset, in contrast with the long-held view that during this early stage all complex stimuli are processed equally and that category-specific cortical activation occurs only at later stages. The neural basis of this proposed early stage of high-level analysis is however poorly understood. To address this question we used magnetoencephalography and anatomically-constrained distributed source modeling to monitor brain activity with millisecond-resolution while subjects performed an orientation task on the upright and upside-down presented images of three different stimulus categories: faces, houses and bodies. Significant inversion effects were found for all three stimulus categories between 70–100-ms after picture onset with a highly category-specific cortical distribution. Differential responses between upright and inverted faces were found in well-established face-selective areas of the inferior occipital cortex and right fusiform gyrus. In addition, early category-specific inversion effects were found well beyond visual areas. Our results provide the first direct evidence that category-specific processing in high-level category-sensitive cortical areas already takes place within the first 100-ms of visual processing, significantly earlier than previously thought, and suggests the existence of fast category-specific neocortical routes in the human brain

Neuropsychological Generation of Source Amnesia: An Episodic Memory Disorder of the Frontal Brain

Source amnesia is an explicit memory (declarative) disorder, particularly episodic, where source or contextual information concerning facts is severely distorted and/or unable to be recalled. This paper reviews the literature on source amnesia, including memory distrust syndrome, and its accepted correlation with the medial diencephalic system and the temporal lobes, and the suggested linkage between the frontal lobes, including special interest with the prefrontal cortex. Posthypnotic induction was the first presentation of source amnesia identified in the literature. The Wisconsin Cart Sorting Test (WCST), Positron Emission Topography (PET), Phonemic Verbal Fluency Test, Stroop Color Word Interference Test, and explicit and implicit memory tests are defined and linked to empirical research on amnesiacs

Early Category-Specific Cortical Activation Revealed by Visual Stimulus Inversion

Visual categorization may already start within the first 100-ms after stimulus onset, in contrast with the long-held view that during this early stage all complex stimuli are processed equally and that category-specific cortical activation occurs only at later stages. The neural basis of this proposed early stage of high-level analysis is however poorly understood. To address this question we used magnetoencephalography and anatomically-constrained distributed source modeling to monitor brain activity with millisecond-resolution while subjects performed an orientation task on the upright and upside-down presented images of three different stimulus categories: faces, houses and bodies. Significant inversion effects were found for all three stimulus categories between 70–100-ms after picture onset with a highly category-specific cortical distribution. Differential responses between upright and inverted faces were found in well-established face-selective areas of the inferior occipital cortex and right fusiform gyrus. In addition, early category-specific inversion effects were found well beyond visual areas. Our results provide the first direct evidence that category-specific processing in high-level category-sensitive cortical areas already takes place within the first 100-ms of visual processing, significantly earlier than previously thought, and suggests the existence of fast category-specific neocortical routes in the human brain

Neural Processes Supporting Young and Older Adults' Emotional Memories

Young and older adults are more likely to remember emotional information than neutral information. The present functional magnetic resonance imaging study examined the neural processes supporting young (ages 18-35) and older (ages 62-79) adults' successful encoding of positive, negative, and neutral objects (e.g., a sundae, a grenade, a canoe). The results revealed general preservation of the emotional memory network across the age groups. Both groups recruited the amygdala and the orbito-frontal cortex during the successful encoding of positive and negative information. Both ages also showed valence-specific recruitment: right fusiform activity was greatest during the successful encoding of negative information, whereas left prefrontal and temporal activity was greatest during the successful encoding of positive information. These valence-specific processes are consistent with behavioral evidence that negative information is processed with perceptual detail, whereas positive information is processed at a conceptual or schematic level. The only age differences in emotional memory emerged during the successful encoding of positive items: Older adults showed more activity in the medial prefrontal cortex and along the cingulate gyrus than young adults. Because these regions often are associated with self-referential processing, these results suggest that older adults' mnemonic boost for positive information may stem from an increased tendency to process this information in relation to themselves.Psycholog

Reduced Specificity of Hippocampal and Posterior Ventrolateral Prefrontal Activity during Relational Retrieval in Normal Aging

Neuroimaging studies of episodic memory in young adults demonstrate greater functional neural activity in ventrolateral pFC and hippocampus during retrieval of relational information as compared with item information. We tested the hypothesis that healthy older adults—individuals who exhibit behavioral declines in relational memory—would show reduced specificity of ventrolateral prefrontal and hippocampal regions during relational retrieval. At study, participants viewed two nouns and were instructed to covertly generate a sentence that related the words. At retrieval, fMRIs were acquired during item and relational memory tasks. In the relational task, participants indicated whether the two words were previously seen together. In the item task, participants indicated whether both items of a pair were previously seen. In young adults, left posterior ventrolateral pFC and bilateral hippocampal activity was modulated by the extent to which the retrieval task elicited relational processing. In older adults, activity in these regions was equivalent for item and relational memory conditions, suggesting a reduction in ventrolateral pFC and hippocampal specificity with normal aging.Psycholog

The hippocampus and cerebellum in adaptively timed learning, recognition, and movement

The concepts of declarative memory and procedural memory have been used to distinguish two basic types of learning. A neural network model suggests how such memory processes work together as recognition learning, reinforcement learning, and sensory-motor learning take place during adaptive behaviors. To coordinate these processes, the hippocampal formation and cerebellum each contain circuits that learn to adaptively time their outputs. Within the model, hippocampal timing helps to maintain attention on motivationally salient goal objects during variable task-related delays, and cerebellar timing controls the release of conditioned responses. This property is part of the model's description of how cognitive-emotional interactions focus attention on motivationally valued cues, and how this process breaks down due to hippocampal ablation. The model suggests that the hippocampal mechanisms that help to rapidly draw attention to salient cues could prematurely release motor commands were not the release of these commands adaptively timed by the cerebellum. The model hippocampal system modulates cortical recognition learning without actually encoding the representational information that the cortex encodes. These properties avoid the difficulties faced by several models that propose a direct hippocampal role in recognition learning. Learning within the model hippocampal system controls adaptive timing and spatial orientation. Model properties hereby clarify how hippocampal ablations cause amnesic symptoms and difficulties with tasks which combine task delays, novelty detection, and attention towards goal objects amid distractions. When these model recognition, reinforcement, sensory-motor, and timing processes work together, they suggest how the brain can accomplish conditioning of multiple sensory events to delayed rewards, as during serial compound conditioning.Air Force Office of Scientific Research (F49620-92-J-0225, F49620-86-C-0037, 90-0128); Advanced Research Projects Agency (ONR N00014-92-J-4015); Office of Naval Research (N00014-91-J-4100, N00014-92-J-1309, N00014-92-J-1904); National Institute of Mental Health (MH-42900

Brain networks involved in decision making: an electroencephalography and magnetic resonance imaging study

Executive function describes high-level cognitive-abilities including planning, decision-making, set switching and response inhibition. Impairments of the executive functions in disease states may be subtle but can greatly reduce the quality of life and independence. The overarching theme of this project was to investigate the network of brain regions that are needed to support executive function. This was undertaken using a two-fold approach: one, to apply network analysis to resting state functional Magnetic Resonance Imaging (rs-fMRI) and Diffusion Tensor Imaging (DTI) data in order to describe how differences in morphometry and connectivity correlate to executive function differences of individuals with Mild Cognitive Impairment (MCI), and two, to describe the brain networks involved in one form of executive function, decision-making under uncertain conditions, in young, healthy individuals. Impaired decision-making can dramatically impact day-to-day functioning and understanding the underlying network of regions that support this task can provide a target for future intervention studies. Data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) were used in the studies of MCI. Individuals were grouped by their executive abilities. A regions-of-interest approach was used to parcel and label various brain regions and a network of connections was constructed out of these regions. Differences between the networks were then compared between the MCI subjects with good and poor executive functions. Those with high executive abilities showed decreased functional network connectivity and increased structural network connectivity. The second arm of these studies was based an original decision-making paradigm that was used to compare of networks involved in decision-making at times of uncertainty in healthy young individuals using both electroencephalography (EEG) and task-based functional magnetic resonance imaging (fMRI). Overall we found greater network connectivity in the uncertain condition of the task than in the certain condition. This suggests that with increased uncertainty comes increased organized connectivity. Taken together, the results of this study re-iterate the notion that cognition depends upon the efficient communication between a network of brain regions rather than on isolated regions. They also highlight the importance of having a well-defined network of nodes and connections for optimal executive functioning

The guilty brain: the utility of neuroimaging and neurostimulation studies in forensic field

Several studies have aimed to address the natural inability of humankind to detect deception and accurately discriminate lying from truth in the legal context. To date, it has been well established that telling a lie is a complex mental activity. During deception, many functions of higher cognition are involved: the decision to lie, withholding the truth, fabricating the lie, monitoring whether the receiver believes the lie, and, if necessary, adjusting the fabricated story and maintaining a consistent lie. In the previous 15 years, increasing interest in the neuroscience of deception has resulted in new possibilities to investigate and interfere with the ability to lie directly from the brain. Cognitive psychology, as well as neuroimaging and neurostimulation studies, are increasing the possibility that neuroscience will be useful for lie detection. This paper discusses the scientific validity of the literature on neuroimaging and neurostimulation regarding lie detection to understand whether scientific findings in this field have a role in the forensic setting. We considered how lie detection technology may contribute to addressing the detection of deception in the courtroom and discussed the conditions and limits in which these techniques reliably distinguish whether an individual is lying