By: Alireza Hejazi

 

The amazing story of future processing in human brain has been of great attention among many neuroscientists, psychologists and even social researchers. Each of them has regarded the issue from a distinctive point of view. Their researches are proceeding in new ways and methods and we should wait for more interesting results in the coming time. The interesting contents of a number of articles that I have received yet made me to make a review by compiling their abstracts in the following. I hope these cues may enable those who are interested in studying more about this important issue. Perhaps in the near future we may have to make a serious review concerning our past understandings on the way that our brain thinks about the future.

     

Neural substrates of envisioning the future

The ability to envision specific future episodes is a ubiquitous mental phenomenon that has seldom been discussed in the neuroscience literature. In a  study done at department of Psychology, Washington University, subjects underwent functional MRI while using event cues (e.g., Birthday) as a guide to vividly envision a personal future event, remember a personal memory, or imagine an event involving a familiar individual. Two basic patterns of data emerged. One set of regions (e.g., within left lateral premotor cortex; left precuneus; right posterior cerebellum) was more active while envisioning the future than while recollecting the past (and more active in both of these conditions than in the task involving imagining another person). These regions appear similar to those emerging from the literature on imagined (simulated) bodily movements. A second set of regions (e.g., bilateral posterior cingulate; bilateral parahippocampal gyrus; left occipital cortex) demonstrated indistinguishable activity during the future and past tasks (but greater activity in both tasks than the imagery control task); similar regions have been shown to be important for remembering previously encountered visual-spatial contexts.

Hence, differences between the future and past tasks are attributed to differences in the demands placed on regions that underlie motor imagery of bodily movements, and similarities in activity for these two tasks are attributed to the reactivation of previously experienced visual?spatial contexts. That is, subjects appear to place their future scenarios in well known visual?spatial contexts. These results offer insight into the fundamental and little-studied capacity of vivid mental projection of oneself in the future. For more information view: http://www.pnas.org_cgi_doi_10.1073_pnas.0610082104

 

Imagining the future

People can consciously re-experience past events and pre-experience possible future events. A recent fMRI study examined the neural regions mediating the construction and elaboration of past and future events. Participants were cued with a noun for 20 s and instructed to construct a past or future event within a specified time period (week, year, 5?20 years). Once participants had the event in mind, they made a button press and for the remainder of the 20 s elaborated on the event. Importantly, all events generated were episodic and did not differ on a number of phenomenological qualities (detail, emotionality, personal significance, field/observer perspective). Conjunction analyses indicated the left hippocampus was commonly engaged by past and future event construction, along with posterior visuospatial regions, but considerable neural differentiation was also observed during the construction phase.

Future events recruited regions involved in prospective thinking and generation processes, specifically right frontopolar cortex and left ventrolateral prefrontal cortex, respectively. Furthermore, future event construction uniquely engaged the right hippocampus, possibly as a response to the novelty of these events. In contrast to the construction phase, elaboration was characterized by remarkable overlap in regions comprising the autobiographical memory retrieval network, attributable to the common processes engaged during elaboration, including self-referential processing, contextual and episodic imagery. This striking neural overlap is consistent with findings that amnesic patients exhibit deficits in both past and future thinking, and confirms that the episodic system contributes importantly to imagining the future.

The bibliographic information of this research article is available at: http://dx.doi.org/10.1016/j.neuropsychologia.2006.10.016

 

Neural mechanisms mediating future oriented optimism

Humans expect positive events in the future even when there is no evidence to support such expectations. For example, people expect to live longer and be healthier than average, they underestimate their likelihood of getting a divorce1, and overestimate their prospects for success on the job market. A group of researchers examined how the brain generates this pervasive optimism bias. Here we report that this tendency was related specifically to enhanced activation in the

amygdala and in the rostral anterior cingulate cortex when imagining positive future events relative to negative ones, suggesting a key role for areas involved in monitoring emotional salience in mediating the optimism bias. These are the same regions that show irregularities in depression, which has been related to pessimism.

Across individuals, activity in the rostral anterior cingulated cortex was correlated with trait optimism. The current study highlights how the brain may generate the tendency to engage in the projection of positive future events, suggesting that the effective integration and regulation of emotional and autobiographical information supports the projection of positive future events in healthy individuals, and is related to optimism.

The results of this study can be reviewed at: http://www.nature.com/doifinder/10.1038/nature06280

 

 

Neuroanatomical Substrates of Foresight in Schizophrenia

The ability to think of the long-term consequences of one's behavior and use this information to guide present and future actions, commonly referred to as foresight, is a key higher-order cognitive ability that may be deficient among persons with schizophrenia and substantially limit the degree to which such individuals experience a functional recovery from the disease. A remarkable research done at University of Pittsburgh School of Medicine investigated the neuroanatomical basis of foresight in schizophrenia, in order to identify potential brain regions that may underly impaired foresightfulness among this population. Participants in the early course of schizophrenia or schizoaffective disorder (N = 50) were assessed using structural magnetic resonance imaging and clinician-rated measures of foresight and psychopathology. Voxel-based morphometry was used to examine the relationship between foresight and regional gray matter volume in the ventromedial prefrontal, orbitofrontal and cingulate cortices. Significant positive associations were observed between foresight and gray matter volume density in the right orbitofrontal, ventromedial prefrontal, and posterior cingulate cortices, as well as the left ventromedial prefrontal and anterior cingulate cortices, after correcting for multiple comparisons.

These relationships persisted after adjusting for age, gender, illness duration, and psychopathology. Better foresight was most strongly associated with increased gray matter in the right orbitofrontal/ventromedial prefrontal cortex, suggesting that reductions in gray matter volume in this region may be associated with impaired foresight in schizophrenia. Implications and directions for future research are discussed.

The result of this research published in final edited form as: Schizophr Res. 2008 August ; 103(1-3): 62?70. doi:10.1016/j.schres.2008.05.012.

 

Psychological travel through time

Although we can't technically travel through time, when we think of the past or the future we engage in a sort of mental time travel. This uniquely human ability to psychologically travel through time arguably sets us apart from other species. Researchers have recently looked at how mental time travel is represented in the sensorimotor systems that regulate human movement. It turns out our perceptions of space and time are tightly coupled.

University of Aberdeen psychological scientists Lynden Miles, Louise Nind and Neil Macrae conducted a study to measure this in the lab. They fitted participants with a motion sensor while they imagined either future or past events. The researchers found that thinking about past or future events can literally move us: Engaging in mental time travel (a.k.a. chronesthesia) resulted in physical movements corresponding to the metaphorical direction of time. Those who thought of the past swayed backward while those who thought of the future moved forward.

These findings reported online in Psychological Science, a journal of the Association for Psychological Science, suggest that chronesthesia may be grounded in processes that link spatial and temporal metaphors (e.g., future= forward, past= backward) to our systems of perception and action. "The embodiment of time and space yields an overt behavioral marker of an otherwise invisible mental operation," explains Miles and colleagues. The original news is available at: http://www.physorg.com/news183297421.html

 

 

The problem of duration

Perceived duration is conventionally assumed to correspond with objective duration, but a growing literature suggests a more complex picture. For example, repeated stimuli appear briefer in duration than a novel stimulus of equal physical duration. Scientists suggest that such duration illusions appear to parallel the neural phenomenon of repetition suppression, and they marshal evidence for a new hypothesis: the experience of duration is a signature of the amount of energy expended in representing a stimulus, i.e. the coding efficiency. This novel hypothesis offers a unified explanation for almost a dozen illusions in the literature in which subjective duration is modulated by properties of the stimulus such as size, brightness, motion and rate of flicker. For more information you can study a useful article written by David M. Eagleman and Vani Pariyadath titles: "Is subjective duration a signature of coding efficiency?" The article can be downloaded from: http://rstb.royalsocietypublishing.org/