Interests in Psychology

Laterality            Sleep and Circadian Rhythms

Studies concerning the way humans process information confirm that both sides of the brain are involved in almost every human activity, however it has also been long-established that each cerebral hemisphere is differentially involved in various mental processes. Generally, the left hemisphere is associated with verbal language tasks, while the right hemisphere is associated with nonverbal visuospatial tasks. Currently I am working on a study that assess laterality using dual-task procedures. In a dual-task procedure, participants are asked to perform a hemisphere-specific motor activity concurrently with a hemisphere-specific cognitive task. In this model, asymmetrical performance in the motor task is associated with engagement of the contralateral hemisphere. Thus, participants show more right than left manual interference when engaging in a concurrent left-hemispheric task, such as reciting nursery rhymes, reading or solving anagrams. Similarly participants show more left than right manual interference when engaging in a concurrent right-hemispheric task, such as picture identification, matching line drawings or completing block designs. finger tapping Finger tapping is perhaps the most common motor activity utilized in dual-task procedures. With finger tapping, participants are asked to tap a switch as quickly and consistently as possible. The amount of interference associated with a concurrent task is typically assessed by comparing finger tapping performance of each hand, with and without the concurrent task. Lateralized reductions in finger tapping rates have been attributed to competition for hemispheric-specific pools of resources. According to this theory, each hemisphere represents a limited, finite pool of resources. By performing in two concurrent tasks that use the same resources, performance on both tasks is diminished. The functional cerebral distance theory has also been used to explain lateralized changes in finger tapping rates. Based on the understanding of the brain as a collection of specialized neural networks, this theory holds that common interconnections make it difficult to perform two activities that are processed in the same local neural networks. Back to Top

boy sleepingSleep and Circadian Rhythms
Sleep is a brain process that is both universal and essential to survival (Pressman and 
Orr, 1997). However, due to inadequate technology and some preconceived notions, sleep was not really studied 
until the last 60 years.  So far, it looks like sleep is important for development of the brain early in life, the 
maintenance of instinctual processes and for memory.  What sleep actually does for the brain at a molecular and 
cellular level is still a mystery. This makes sleep an exciting area of study for researchers.
Closely linked to the study of sleep, is the study of circadian rhythms.  Circadian rhythms refer to the daily 
fluctuations in our biological rhythms.  For example, we sleep and wake in a regular cycle and our body temperature 
varies slightly depending on the time of day it is.
	Studies in time-of-day research have shown that performance on verbal tasks, such as word and prose recall, 
peaks in the morning and declines over the course of the day.  However, performance on spatial tasks, such as 
identifying objects or faces, is low in the morning and increases during the course of the day.  Recently it has 
been suggested that perhaps these differences in performance patterns may reflect a shift from more left hemispheric 
involvement in the morning to more right hemispheric involvement in the afternoon. In my thesis, I hope to examine 
this hypothesis using techniques commonly used in laterality research.

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