In "The Cognitive Neurosciences III", there are over 1000 pages devoted to explaining the relationship between mind and brain. At the most general level, human cognitive processing occurs in the cortex, the outer layer of the brain composed of folds (gyri) and crevices (sulci) of tissue. Specific regions of tissue are devoted to distinct cognitive processes. For example, there are regions for visual processing, decision making, language, and so one. As scientists continue to examine cognitive function using brain imaging techniques, the cortical map is becoming more and more detailed.
One of the most common presentations of the brain and the cognitive functions that occur within it is in terms of four primary regions: the occipital, temporal, parietal, and frontal lobes.
The Occipital Lobe
The occipital lobe is devoted to visual processing. It lies at the back of the head, furthest from the eyes. Information is sent from the retina to the primary visual cortex (V1), also referred to as the striate cortex. There is perfect correspondence between the retinal image and the cellular encoding in V1 (striate cortex), which is completed in terms of contrast and orientation. From there, information from the retinal image is sent forward to distinct regions of the occipital lobe for more complex encoding, called extra striate cortex, including V2 (discrimination, orientation, and color), V4 (shape), and V5 (motion).
The Temporal Lobe
The temporal lobe is located on the bottom, or ventral, portion of the brain. Visual information is sent to the temporal lobe when it must be processed in terms of "what" it is. This capacity draws on processes related to recognition, naming and associative memory. For example, some areas are dedicated to face and place processing. Wernicke's area, important for language comprehension, is located in the temporal lobe. In addition, the temporal lobe is the home of the auditory cortex for sound processing.
The Parietal Lobe
The parietal lobe is located on the top, or dorsal, portion of the brain. Visual information is sent to the parietal lobe when it must be processed in terms of "where" it is located. The parietal cortex is also home to the sensory cortex, and it provides a place for sensation and perception to be integrated. This lobe is most commonly associated with its capacity for spatial processing. It is here that external visual, or environment based, coordinates may be translated into internal, or body-based,coordinates and vice versa.
The Frontal Lobe
The frontal lobe is the seat of executive functioning. Decisions are made here, information is monitored, and pros and cons are considered. Moreover, it is related to memory, emotion, and personality. But it is also a place for motor processing. Immediately in front of, or anterior to, the central sulcus, resides the primary motor cortex (M1), followed by the supplementary area (SMA) and the premotor cortex (PMC). These three regions are responsible for the processing of internally and externally driven motor commands, the motor plans that accompany them, and the executive control needed to perform actions successfully. Finally, in the left hemisphere, Broca's area, dedicated to language production, can be found.
References
- "The Cognitive Neurosceinces III"; Michael S. Gazzaniga, Ph.D.; 2004
