Cognitive and affective Theory of Mind double dissociation after parietal and temporal lobe tumors

Extensive neuroimaging literature suggests that understanding others' thoughts and emotions engages a wide network encompassing parietal, temporal and medial frontal brain areas. However, the causal role played by these regions in social inferential abilities is still unclear. Moreover very little is known about ToM deficits in brain tumours and whether potential anatomical substrates are comparable to those identified in fMRI literature. This study evaluated the performance of 105 tumour patients, before and immediately after brain surgery, on a cartoon-based non-verbal task evaluating Cognitive (Intention Attribution) and Affective (Emotion Attribution) ToM, as well as a non-social control condition (Causal Inference). Across multiple analyses, we found converging evidence of a double dissociation between patients with right superior parietal damage, selectively impaired in Intention Attribution, and those with right antero-medial temporal lesion, exhibiting deficits only in Emotion attribution. Instead, patients with damage to the frontal cortex were impaired in all kinds of inferential processes, including those from the non-social control conditions. Overall, our data provides novel reliable causal evidence of segregation between different aspects of the ToM network from both the cognitive and also the anatomical point of view.

Circuit mechanisms for the chemical modulation of cortex-wide network interactions and behavioral variability

Influential theories postulate distinct roles of catecholamines and acetylcholine in cognition and behavior. However, previous physiological work reported similar effects of these neuromodulators on the response properties (specifically, the gain) of individual cortical neurons. Here, we show a double dissociation between the effects of catecholamines and acetylcholine at the level of large-scale interactions between cortical areas in humans. A pharmacological boost of catecholamine levels increased cortex-wide interactions during a visual task, but not rest. An acetylcholine boost decreased interactions during rest, but not task. Cortical circuit modeling explained this dissociation by differential changes in two circuit properties: the local excitation-inhibition balance (more strongly increased by catecholamines) and intracortical transmission (more strongly reduced by acetylcholine). The inferred catecholaminergic mechanism also predicted noisier decision-making, which we confirmed for both perceptual and value-based choice behavior. Our work highlights specific circuit mechanisms for shaping cortical network interactions and behavioral variability by key neuromodulatory systems.

The contribution of episodic Long-term Memory to Working Memory for Bindings.

The Binding Hypothesis of working memory (WM) is that WM capacity is limited by interference between bindings but not items. It implies the prediction that with increasing set size, memory for bindings should decline, whereas memory for items should be (largely) unimpaired. Here we test the binding hypothesis for bindings between words and pictures. The first experiment supported the binding hypothesis, yet also revealed a strong hint that episodic LTM contributed substantially to binding memory, especially at larger set sizes. Therefore, our second goal was to investigate this contribution, and to isolate it from the contribution of WM to binding memory. Across three additional experiments we showed a double dissociation of contributions of WM and episodic LTM to binding memory: Performance at set sizes larger than 3 were specifically affected by proactive interference – but were immune to influences from a distractor filled delay. In contrast, performance at set size 2 was unaffected by proactive interference but harmed by a distractor filled delay.

Distinct Origins of Two-order Hierarchical Cognitive Abilities in Human Adults

Human cognitive abilities are considerably diverse from basic perceptions to complex social behaviors. All human cognitive functions are principally categorized into a two-order hierarchy. Almost all of the first-order cognitive abilities investigated in behavioral genetics have been found to be dominantly heritable. However, the origins of the human second-order cognitive abilities in metacognition and mentalizing so far remain unclear. We here systematically compared the origins of the first-order and second-order cognitive abilities involved in the metacognition and mentalizing tasks using the classical twin paradigm on human adults. Our results demonstrated a double dissociation of the genetic and environmental contributions to the first-order and second-order cognitive abilities. All the first-order cognitive abilities involved in the metacognition and mentalizing tasks were dominantly heritable. In contrast, the shared environmental effects, rather than the genetic effects, had dominant contributions to the second-order cognitive abilities of metacognition and mentalizing in human adults. Hence, our findings suggest that human adults' monitoring sensitivities in metacognition and mentalizing are profoundly sculpted by their social or cultural experiences, but less preconditioned by their biological nature.

How Associative Thinking Influences Scene Perception

Perception of our external environment is not isolated from the influence of our internal thoughts. Here, we investigate the nature of their interaction. We argue that a common associative mechanism underlies both the perception of scenes and our internal thoughts, and in three experiments hypothesize that there is a functional advantage to an associative thought pattern in the perception of scenes. Experiments 1 and 2 showed that associative thinking indeed facilitates scene perception, an effect that evolved over the course of the experiments. Experiment 3 showed that associative thinking hinders the perception of individual, isolated objects, in which associative information is minimized, but that object perception is facilitated when associative thinking is reduced. This double dissociation reveals that a match between the orientation of internal and external processing is key for perception, suggesting that an associative mind is more receptive of externally perceived associative information.

Disentangling Perceptual Awareness from Non-conscious Processing in Rhesus Monkeys (Macaca mulatta)

Scholars have long debated whether animals, which display impressive intelligent behaviors, are consciously aware or not. Yet, because many complex human behaviors and high-level functions can be performed without conscious awareness, it was long considered impossible to untangle whether animals are aware, or just conditionally or non-consciously behaving. Here, we developed a novel empirical approach to address this question. We harnessed a well-established crossover double dissociation between non-conscious and conscious processing, in which people perform in completely opposite ways when they are aware of stimuli versus when they are not. To date, no one has explored if similar performance dissociations exist in a non-human species. In a series of seven experiments, we first established these signatures in humans using both known and newly developed non-verbal double dissociation tasks, and then identified similar signatures in rhesus monkeys (Macaca mulatta). These results provide robust evidence for two distinct modes of processing in non-human primates. This empirical approach makes it feasible to disentangle conscious visual awareness from non-conscious processing in non-human species; hence, it can be used to strip away ambiguity when exploring the processes governing intelligent behavior across the animal kingdom. Taken together, these results strongly support the existence of both non-conscious processing as well as functional human-like visual awareness in non-human animals.

Disentangling perceptual awareness from nonconscious processing in rhesus monkeys (Macaca mulatta)

Scholars have long debated whether animals, which display impressive intelligent behaviors, are consciously aware or not. Yet, because many complex human behaviors and high-level functions can be performed without conscious awareness, it was long considered impossible to untangle whether animals are aware or just conditionally or nonconsciously behaving. Here, we developed an empirical approach to address this question. We harnessed a well-established cross-over double dissociation between nonconscious and conscious processing, in which people perform in completely opposite ways when they are aware of stimuli versus when they are not. To date, no one has explored if similar performance dissociations exist in a nonhuman species. In a series of seven experiments, we first established these signatures in humans using both known and newly developed nonverbal double-dissociation tasks and then identified similar signatures in rhesus monkeys (Macaca mulatta). These results provide robust evidence for two distinct modes of processing in nonhuman primates. This empirical approach makes it feasible to disentangle conscious visual awareness from nonconscious processing in nonhuman species; hence, it can be used to strip away ambiguity when exploring the processes governing intelligent behavior across the animal kingdom. Taken together, these results strongly support the existence of both nonconscious processing as well as functional human-like visual awareness in nonhuman animals.