Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience

1. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press Chapter 5 The Brain “The brain is contained within the cranium, and constitutes the upper, greatly expanded part of the central nervous system.” Henry Gray, Anatomy of the Human Body, 1918

2. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press Chapter Outline 1.0 Introduction 2.0 Growing the brain from the bottom up 3.0 From ‘where’ to ‘what’: the functional roles of brain regions 4.0 Summary

3. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The nervous system … The two main parts of the nervous system are the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which includes the autonomic and peripheral sensory and motor system. Together, the CNS and PNS provide a dynamic and massive communication system throughout all parts of the body, with a hub at the brain that is accessed through the spinal cord.

4. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The CNS … The brain sits atop the CNS, a dynamic and highly interconnected hub of activity. Here is a side -- or lateral -- view of the brain inside the head. The slice is taken at the mid-sagittal position, in the center of the brain between the two hemispheres.

5. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The geography of the brain The four major lobes of the brain are visible from a lateral view. A lateral view of the left hemisphere, with the frontal lobe (purple) at the anterior of the brain, the parietal lobe (orange) posterior to the frontal lobe at the superior aspect of the brain, the temporal lobe (blue) posterior to the frontal lobe and inferior to the parietal lobe, and the occipital lobe (yellow) which is posterior to both the parietal and temporal lobes.

6. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The geography of the brain Some important landmarks of the brain in the left hemisphere from a lateral perspective (left panel) and a mid-sagittal perspective (right panel).

7. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The geography of the brain The Brodmann classification (based on microscopic cell differences) of regions in the left hemisphere, shown in a lateral view. Areas 41 & 52 are indicated by lines. Some areas, like the insula and auditory region, are tucked away behind the temporal lobe.

8. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The geography of the brain The Brodmann classification of regions in the left hemisphere in mid-sagittal view.

9. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 1.0 Introduction The geography of the brain A schematic drawing of the six layers in the gray matter of the cortex. Some cortical neurons send their axons to the thalamus, while others receive input from thalamic neurons.

10. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 2.0 Growing a brain from the bottom up Evolution and personal history are expressed in the brain The brain has grown and evolved from the inside out, much like a seed grows into a tree. Lower regions like the brainstem are generally more ancient than higher regions, such as the frontal cortex. Basic survival functions like breathing are controlled by neural centers in the lower brainstem, while the large prefrontal cortex in humans is a late addition to the basic mammalian brain plan.

11. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 2.0 Growing a brain from the bottom up Building a brain from bottom to top The brain builds on the brainstem, with the thalami on top as a major input hub. The hippocampi and amygdalas are actually nestled inside each of the temporal lobes. The light blue ventricles have no neurons, but provide the brain’s own circulatory system. The basal ganglia can be thought of as the output hub of the system. A great deal of traffic flows back to the cortex as well.

12. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 2.0 Growing a brain from the bottom up Building a brain from bottom to top The cerebral hemispheres are shown mounted above the brainstem and the other subcortical bodies.

13. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The cerebral hemispheres: the left-right division The two hemispheres are completely separate, divided by the longitudinal fissure that runs between the two hemispheres from the anterior to the posterior part of the brain. A schematic view of the two hemispheres, showing some major functions of the left and right hemispheres.

14. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The cerebral hemispheres: the left-right division How do the hemispheres ‘talk’ to each other? The link between the hemispheres is provided by the corpus callosum, a large arch of white matter, shown in this cut-away of a 3-dimensional MRI.

15. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions Output and input: the front-back division The frontal lobe typically is involved in executive and motor (output) functions. The posterior half of the brain is involved in sensory processing. A view of functional areas in sensory regions of the cortex: the central sulcus separates the frontal lobe from the parietal. Immediately anterior to the central sulcus are motor areas, and just posterior to the central sulcus is the primary somatosensory area.

16. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions Output and input: the front-back division A homonculus (‘little man’) shows the body map for motor representation of different areas of the body. Note that some body areas, such as the fingers, have disproportionately larger representation than other body areas, such as the trunk.

17. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions Output and input: the front-back division A homonculus (‘little man’) shows the body map for somatosensory representation of different areas on the body. Note that some body areas, such as the face, have disproportionately larger representation than other body areas, such as the trunk.

18. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions Output and input: the front-back division The close physical connection between motor cortex, located just anterior to the central sulcus, and the somatosensory cortex, located just posterior to it, allows for a tight coupling between the senses of touch, pressure, and pain and the action or motor system.

19. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The major lobes: visible and hidden The frontal lobe is the site for motor planning and motor output, but in humans the frontal lobe -- especially the prefrontal cortex -- performs many other functions: Initiating activities Planning Holding critical information ready to use Changing mental set from one line of thinking to another Monitoring the effectiveness of ones actions Inhibiting plans and actions that are ineffective or self defeating

20. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The major lobes: visible and hidden central sulcus How to locate the prefrontal cortex: The frontal lobe lies anterior to the central sulcus. The two purple gyri (hills) immediately in front of the central sulcus are call the motor and premotor cortex. The reddish purple patch in front of that is called the supplementary motor cortex. The three shades of yellow in the frontal third of the whole cortex is the prefrontal cortex, often considered the most ‘cognitive’ part of the brain.

21. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The parietal lobe is posterior to the frontal lobe. The anterior portion of the parietal lobe contains somatosensory cortex. One important function of the parietal lobe that it contains multiple maps of body space. Other important functions are multisensory integration.

22. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The temporal lobe is posterior to the frontal lobe and inferior to the parietal lobe. The temporal lobe contains auditory cortex where sound is processed, as well as language reception and comprehension regions. The middle regions of the temporal lobe are important to memory and the inferior posterior regions are involved in visual object representation.

23. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The occipital lobe, located at the posterior of the brain, is home to visual cortex. The visual system occupies a large region of the occipital lobe that extends upwards to the parietal lobe and anterior to the temporal lobe.

24. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The massive interconnnectivity of the cortex and thalamus The cortex and thalamus are a massively interconnected system: color coding shows the mapping of connections between cortical and thalamic regions.

25. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 3.0 From ‘where’ to ‘what’: the functional roles of brain regions The massive interconnnectivity of the cortex Top: schematic drawing of the connectivity of the brain, showing major fiber patterns. Bottom: diffusion tensor image of white bundles of myelinated axons which run in all directions through the cortical domes.

26. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press 4.0 Summary Important concepts: The brain has developed and changed through time and so some areas of the brain are ‘older’ than others. The cortex represents recent brain developments in the human, and frontal and parietal lobes have expanded their neural territory as compared to non-human primates. While there are separate regions and parts of the brain, such as the two hemispheres and the four lobes, the brain is highly interconnected with an extensive fiber pathway system that connects the hemispheres, the lobes, and provides circuits to subcortical regions.