Neuroanatomy (Part 3)
Nevertheless, the cerebral hemispheres possess similarities. Both hemispheres also possess similarities. Both hemispheres are made up of six lobes. They are the frontal, parietal, occipital, temporal, insular, and limbic lobes (O’ Sullivan and Siegleman, 2006).
The frontal lobe controls and activates the voluntary muscles of the body (precentral gyrus). It also controls an individual’s emotions and judgments (prefrontal cortex). Furthermore, there is also a portion of the frontal lobe that controls the motor aspects of speech (Broca’s area). The frontal lobe also stores long term memory, together with the temporal lobe, hippocampus, amygdala, and the diencephalon.
The parietal lobe contains the primary sensory cortex for integration of sensation (postcentral gyrus). The said part of the cortex receives fibers conveying touch, proprioceptive, pain, and temperature sensations from opposite side of the body.
The occipital lobe receives and interprets visual stimuli via the primary and association visual cortex.
The temporal lobe interprets auditory stimuli. It is also responsible for storing short term memory.
The area between the temporal and parietal lobe known as the Wernicke’s area acts as the sensory area for speech and comprehension (Figure 17).
Figure 17. Where are the Broca’s area and the Wernicke’s area?
The insular lobe is seated deeply within the lateral sulcus and is associated with the visceral functions.
The limbic system is a system comprising of the cingulated, parahippocampal, and subcallosal gyri, the hippocampal formation, amygdaloid nucleus, hypothalamus, and anterior nuclei of thalamus. Collective functions of these structures are concerned with instincts, feeding, aggression, emotions, and endocrine aspects of sexual response.
If we can observe none of the lobes interpret olfactory stimuli. The reason is that there is a separate cortex that does such function (olfactory cortex) which is in close coordination with the uncus.
The Cortical Homunculus
The cortical homunculus is used to describe the distorted human figure (Figure18) that depicts the space our body parts occupy on the somatosensory and motor cortex. Normally the lips, hands, feet, and sex organs have more sensory and motor neurons. This is the reason why the above body parts are more sensitive and provide finer motor control than any other parts of the body. And so the homunculus has correspondingly distortedly large lips, hands, feet, and genitals.
Figure 18. Homunculus
Another way of illustrating the body parts’ territory on the brain is through the figure below (Figure 19):
Figure 19. The motor (red) and sensory (blue) homunculus.
The frontal lobe controls and activates the voluntary muscles of the body (precentral gyrus). It also controls an individual’s emotions and judgments (prefrontal cortex). Furthermore, there is also a portion of the frontal lobe that controls the motor aspects of speech (Broca’s area). The frontal lobe also stores long term memory, together with the temporal lobe, hippocampus, amygdala, and the diencephalon.
The parietal lobe contains the primary sensory cortex for integration of sensation (postcentral gyrus). The said part of the cortex receives fibers conveying touch, proprioceptive, pain, and temperature sensations from opposite side of the body.
The occipital lobe receives and interprets visual stimuli via the primary and association visual cortex.
The temporal lobe interprets auditory stimuli. It is also responsible for storing short term memory.
The area between the temporal and parietal lobe known as the Wernicke’s area acts as the sensory area for speech and comprehension (Figure 17).
Figure 17. Where are the Broca’s area and the Wernicke’s area?
The insular lobe is seated deeply within the lateral sulcus and is associated with the visceral functions.
The limbic system is a system comprising of the cingulated, parahippocampal, and subcallosal gyri, the hippocampal formation, amygdaloid nucleus, hypothalamus, and anterior nuclei of thalamus. Collective functions of these structures are concerned with instincts, feeding, aggression, emotions, and endocrine aspects of sexual response.
If we can observe none of the lobes interpret olfactory stimuli. The reason is that there is a separate cortex that does such function (olfactory cortex) which is in close coordination with the uncus.
The Cortical Homunculus
The cortical homunculus is used to describe the distorted human figure (Figure18) that depicts the space our body parts occupy on the somatosensory and motor cortex. Normally the lips, hands, feet, and sex organs have more sensory and motor neurons. This is the reason why the above body parts are more sensitive and provide finer motor control than any other parts of the body. And so the homunculus has correspondingly distortedly large lips, hands, feet, and genitals.
Figure 18. Homunculus
Another way of illustrating the body parts’ territory on the brain is through the figure below (Figure 19):
Figure 19. The motor (red) and sensory (blue) homunculus.
