Using action understanding to understand the left inferior parietal cortex in the human brain

Published in final edited form as: Brain Res. 2014 September 25; 1582: 64–76. doi:10.1016/j.brainres.2014.07.035.Humans have a sophisticated knowledge of the actions that can be performed with objects. In an fMRI study we tried to establish whether this depends on areas that are homologous with the inferior parietal cortex (area PFG) in macaque monkeys. Cells have been described in area PFG that discharge differentially depending upon whether the observer sees an object being brought to the mouth or put in a container. In our study the observers saw videos in which the use of different objects was demonstrated in pantomime; and after viewing the videos, the subject had to pick the object that was appropriate to the pantomime. We found a cluster of activated voxels in parietal areas PFop and PFt and this cluster was greater in the left hemisphere than in the right. We suggest a mechanism that could account for this asymmetry, relate our results to handedness and suggest that they shed light on the human syndrome of apraxia. Finally, we suggest that during the evolution of the hominids, this same pantomime mechanism could have been used to ‘name’ or request objects.We thank Steve Wise for very detailed comments on a draft of this paper. We thank Rogier Mars for help with identifying the areas that were activated in parietal cortex and for comments on a draft of this paper. Finally, we thank Michael Nahhas for help with the imaging figures. This work was supported in part by the NIH grant RO1NS064100 to LMV. (RO1NS064100 - NIH)Accepted manuscrip

Reorganization of retinotopic maps after occipital lobe infarction

Published in final edited form as: J Cogn Neurosci. 2014 June ; 26(6): 1266–1282. doi:10.1162/jocn_a_00538.We studied patient JS, who had a right occipital infarct that encroached on visual areas V1, V2v, and VP. When tested psychophysically, he was very impaired at detecting the direction of motion in random dot displays where a variable proportion of dots moving in one direction (signal) were embedded in masking motion noise (noise dots). The impairment on this motion coherence task was especially marked when the display was presented to the upper left (affected) visual quadrant, contralateral to his lesion. However, with extensive training, by 11 months his threshold fell to the level of healthy participants. Training on the motion coherence task generalized to another motion task, the motion discontinuity task, on which he had to detect the presence of an edge that was defined by the difference in the direction of the coherently moving dots (signal) within the display. He was much better at this task at 8 than 3 months, and this improvement was associated with an increase in the activation of the human MT complex (hMT^+) and in the kinetic occipital region as shown by repeated fMRI scans. We also used fMRI to perform retinotopic mapping at 3, 8, and 11 months after the infarct. We quantified the retinotopy and areal shifts by measuring the distances between the center of mass of functionally defined areas, computed in spherical surface-based coordinates. The functionally defined retinotopic areas V1, V2v, V2d, and VP were initially smaller in the lesioned right hemisphere, but they increased in size between 3 and 11 months. This change was not found in the normal, left hemisphere of the patient or in either hemispheres of the healthy control participants. We were interested in whether practice on the motion coherence task promoted the changes in the retinotopic maps. We compared the results for patient JS with those from another patient (PF) who had a comparable lesion but had not been given such practice. We found similar changes in the maps in the lesioned hemisphere of PF. However, PF was only scanned at 3 and 7 months, and the biggest shifts in patient JS were found between 8 and 11 months. Thus, it is important to carry out a prospective study with a trained and untrained group so as to determine whether the patterns of reorganization that we have observed can be further promoted by training.This work was supported by NIH grant R01NS064100 to L. M. V. Lucia M. Vaina dedicates this article to Charlie Gross, who has been a long-time collaborator and friend. I met him at the INS meeting in Beaune (France), and since then we often discussed the relationship between several aspects of high-level visual processing described in his work in monkeys physiology and my work in neuropsychology. In particular, his pioneering study of biological motion in monkeys' superior temporal lobe has influenced my own work on biological motion and has led us to coauthor a paper on this topic. Working with Charlie was a uniquely enjoyable experience. Alan Cowey and I often spoke fondly about Charlie, a dear friend and close colleague to us both, whose work, exquisite sense of humor, and unbound zest of living we both deeply admired and loved. (R01NS064100 - NIH)Accepted manuscrip

Preliminary investigation of flexibility in learning color-reward associations in gibbons (<i>Hylobatidae</i>)

Previous studies in learning set formation have shown that most animal species can learn to learn with subsequent novel presentations being solved in fewer presentations than when they first encounter a task. Gibbons (Hylobatidae) have generally struggled with these tasks and do not show the learning to learn pattern found in other species. This is surprising given their phylogenetic position and level of cortical development. However, there have been conflicting results with some studies demonstrating higher level learning abilities in these small apes. This study attempts to clarify whether gibbons can in fact use knowledge gained during one learning task to facilitate performance on a similar, but novel problem that would be a precursor to development of a learning set. We tested 16 captive gibbons' ability to associate color cues with provisioned food items in two experiments where they experienced a period of learning followed by experimental trials during which they could potentially use knowledge gained in their first learning experience to facilitate solution I subsequent novel tasks. Our results are similar to most previous studies in that there was no evidence of gibbons being able to use previously acquired knowledge to solve a novel task. However, once the learning association was made, the gibbons performed well above chance. We found no differences across color associations, indicating learning was not affected by the particular color / reward association. However, there were variations in learning performance with regard to genera. The hoolock (Hoolock leuconedys) and siamang (Symphalangus syndactylus) learned the fastest and the lar group (Hylobates sp.) learned the slowest. We caution these results could be due to the small sample size and because of the captive environment in which these gibbons were raised. However, it is likely that environmental variability in the native habitats of the subjects tested could facilitate the evolution of flexible learning in some genera. Further comparative study is necessary in order to incorporate realistic cognitive variables into foraging models

The simulation of action disorganisation in complex activities of daily living

Action selection in everyday goal-directed tasks of moderate complexity is known to be subject to breakdown following extensive frontal brain injury. A model of action selection in such tasks is presented and used to explore three hypotheses concerning the origins of action disorganisation: that it is a consequence of reduced top-down excitation within a hierarchical action schema network coupled with increased bottom-up triggering of schemas from environmental sources, that it is a more general disturbance of schema activation modelled by excessive noise in the schema network, and that it results from a general disturbance of the triggering of schemas by object representations. Results suggest that the action disorganisation syndrome is best accounted for by a general disturbance to schema activation, while altering the balance between top-down and bottom-up activation provides an account of a related disorder - utilisation behaviour. It is further suggested that ideational apraxia (which may result from lesions to left temporoparietal areas and which has similar behavioural consequences to action disorganisation syndrome on tasks of moderate complexity) is a consequence of a generalised disturbance of the triggering of schemas by object representations. Several predictions regarding differences between action disorganisation syndrome and ideational apraxia that follow from this interpretation are detailed

The truth-telling motor cortex: Response competition in M1 discloses deceptive behaviour

Neural circuits associated with response conflict are active during deception. Here we use transcranial magnetic stimulation to examine for the first time whether competing responses in primary motor cortex can be used to detect lies. Participants used their little finger or thumb to respond either truthfully or deceitfully regarding facial familiarity. Motor-evoked-potentials (MEPs) from muscles associated with both digits tracked the development of each motor plan. When preparing to deceive, the MEP of the non-responding digit (i.e. the plan corresponding to the truth) exceeds the MEP of the responding digit (i.e. the lie), whereas a mirror-reversed pattern occurs when telling the truth. This give away response conflict interacts with the time of stimulation during a speeded reaction period. Lies can even activate digit-specific cortical representations when only verbal responses are made. Our findings support neurobiological models which blend cognitive decision-making with motor programming, and suggest a novel index for discriminating between honest and intentionally false facial recognition

Effects of ecstasy/polydrug use on memory for associative information

Rationale Associative learning underpins behaviours that are fundamental to the everyday functioning of the individual. Evidence pointing to learning deficits in recreational drug users merits further examination. Objectives A word pair learning task was administered to examine associative learning processes in ecstasy/polydrug users. Methods After assignment to either single or divided attention conditions, 44 ecstasy/polydrug users and 48 non-users were presented with 80 word pairs at encoding. Following this, four types of stimuli were presented at the recognition phase: the words as originally paired (old pairs), previously presented words in different pairings (conjunction pairs), old words paired with new words, and pairs of new words (not presented previously). The task was to identify which of the stimuli were intact old pairs. Results Ecstasy/ploydrug users produced significantly more false-positive responses overall compared to non-users. Increased long-term frequency of ecstasy use was positively associated with the propensity to produce false-positive responses. It was also associated with a more liberal signal detection theory decision criterion value. Measures of long term and recent cannabis use were also associated with these same word pair learning outcome measures. Conjunction word pairs, irrespective of drug use, generated the highest level of false-positive responses and significantly more false-positive responses were made in the divided attention condition compared to the single attention condition. Conclusions Overall, the results suggest that long-term ecstasy exposure may induce a deficit in associative learning and this may be in part a consequence of users adopting a more liberal decision criterion value

The Relationship between Pass Completion Percentage and Perceived Player Workload in NCAA Division I Women\u27s Soccer

In an attempt to demonstrate the interconnecting nature of the pillars of sport (Hacker, 2000) this thesis explores the relationship between physical, psychological and technical variables. Five National Collegiate Athletic Association (NCAA) Division I Women’s Soccer players were analyzed in four conference matches. The athlete\u27s rate of perceived exertion (RPE) values were correlated to pass completion percentages (PC%) to investigate the potential effect that psychological satisfaction or dissatisfaction of technical performance has on perceived exertion ratings. PlayerLoadTM (PL) values, gathered through the utilization of a Catapult Minimax S4 GPS device (miniMax-10 Hz, Catapult Innovations, Melbourne, Australia), were used as a measure of actual workload in order to determine the accuracy of perceived exertion ratings. Results exhibited a trivial correlation (r = 0.028) and large variability (R2 = 0.00077) between RPE and PC% in comparison to PL and PC% (r = 0.50; R2 = 0.2502). The results indicate that an athlete\u27s PC% does not correspond to how physically demanding they perceived a match to be. However, it is possible that performance variables may influence the RPE ratings a player provides

The statistical neuroanatomy of frontal networks in the macaque

We were interested in gaining insight into the functional properties of frontal networks based upon their anatomical inputs. We took a neuroinformatics approach, carrying out maximum likelihood hierarchical cluster analysis on 25 frontal cortical areas based upon their anatomical connections, with 68 input areas representing exterosensory, chemosensory, motor, limbic, and other frontal inputs. The analysis revealed a set of statistically robust clusters. We used these clusters to divide the frontal areas into 5 groups, including ventral-lateral, ventral-medial, dorsal-medial, dorsal-lateral, and caudal-orbital groups. Each of these groups was defined by a unique set of inputs. This organization provides insight into the differential roles of each group of areas and suggests a gradient by which orbital and ventral-medial areas may be responsible for decision-making processes based on emotion and primary reinforcers, and lateral frontal areas are more involved in integrating affective and rational information into a common framework

Connectivity fingerprints: From areal descriptions to abstract spaces

Fifteen years ago, Passingham and colleagues proposed that brain areas can be described in terms of their unique pattern of input and output connections with the rest of the brain, and that these connections are a crucial determinant of their function. We explore how the advent of neuroimaging of connectivity has allowed us to test and extend this proposal. We show that describing the brain in terms of an abstract connectivity space, as opposed to physical locations of areas, provides a natural and powerful framework for thinking about brain function and its variation across the brains of individuals, populations, and species