Brain Study

Dec 18, 2008 by

Brain studyPerhaps most interesting in the contemporary field of brain study are the multiple angles from which science is approaching the infinitely mysterious human brain. Today, the discipline of brain study is enveloped in the larger field of cognitive science, a multidisciplinary branch of science that seeks to understand cognition and cognitive processes in all their manifestations.

The fundamental concept in cognitive science is that “thinking can best be understood in terms of representational structures in the mind, and computational procedures that operate on those structures” (Paul Thagard, “Cognitive Science”, Stanford Dictionary of Philosophy). Cognitive science deals less with internal states of experience (known in philosophy as “qualia’, or “how it feels” to do something), and more with the observable processes of cognition.

Cognitive science draws on a variety of disciplines, including psychology, philosophy, neuroscience, linguistics, anthropology, computer science, biology, and physics. The scope of cognitive science includes subjects like artificial intelligence, attention, language processing, learning and development, memory, and perception and action. These kinds of brain studies focus mostly on the process of understanding, learning, decision-making, and the steps involved in executing an action (or in the case of computing systems, a programmed algorithm).

However sprawling and ambitious it has now become, brain study has its humble and perhaps unexpected beginnings in philosophy—long before the brain and its cognitive functions were well understood. Greek philosophers like Aristotle and Plato were very interested in how the mind perceives and interacts with reality (if indeed it does interact). In the absence of much hard evidence about how the mind worked, or even what it was, the early philosophers mostly used thought experiments to explore questions like “Do humans have free will?” and “What influences do we draw on when making everyday decisions?” Today, scientists are using behavioral experiments and brain imaging to try to answer these same questions.

One of the main tenets of modern brain study is that you cannot understand how the brain operates if you only examine a single level of its operation. For instance, we can study a subject’s behavior in reaction to an assigned task, or use a brain scan to look at the firing patterns of neuron’s in the subject’s brain— but in isolation, these two experiments will not generate a holistic picture of how the brain arrives at a decision and executes an action.Thus, brain study research is also often interdisciplinary, combining inquiry methods drawn from psychology, neuroscience, computer science, and systems theory.

From psychology, researchers studying the brain rely on behavioral experiments. By measuring behavioral responses to different stimuli, one can understand something about how those stimuli are processed, and thus, something about the way the brain functions. Psychologists may study behavioral traces (the evidence of past behavior), directly observe behavior in animal or human subjects, or present subjects with a choice between two distinct behaviors (i.e. pressing one of two levers, each of which produces a distinct result: one might dispense food while the other might deliver a shock, for instance). In each case, psychologists observe and record one or more parameters of behavior and attempt to infer the cognitive, or thinking, processes which underlie them.

These behavioral observations might include reaction time, eye tracking, and psychophysical responses that require a subject to judge sameness or thresholds of things like an auditory tone or a color. Differences in reaction time (slow versus fast) can suggest something about the underlying process of cognition and the items being considered before a person, animal or machine completes a task or makes a decision. Psychophysical response testing is predicated on the concept that two subjects may differ in their perception of a value that can be objectively measured. For instance, two people may be asked to subjectively judge the loudness of a sound that is played at a preset decibel level. The differences in judgment can reveal sensory biases or sensitivities in the subjects. Finally, eye movements are extremely useful in observing cognitive processes, especially in language processing and attention. The eyes focus on whatever a subject is paying mental attention to at the moment, making eye movements a useful empirical tool for studying decision-making on timescales of just a few seconds.

With advances in brain imaging technology, scientists can now directly observe activity within the brain while their subjects are performing various cognitive tasks, such as learning a new activity or making a decision in a lab setting. This allows researchers to link behavior to particular brain functions, thereby helping them understand how information is processed and acted upon. Different imaging techniques measure the amount of oxygenated blood flowing to the brain, either by using radioactive isotopes (as in single photon emission computed tomography (SPECT) and positron emission tomography (PET), or by measuring the electrical or magnetic fields generated by cortical activity, as in electroencephalography, or EEG, and magnetoencephalography respectively.

Next, along with computational modeling utilizing mathematics and formal logic, others who study the brain take research methods directly from neuroscience and neuropsychology. These methods, like single-cell recording, direct brain stimulation, animal models, and postmortem studies, help researchers further understand the mystery of human intelligence.

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