Biopsychology (yr13) Flashcards
What are the 4 lobes in the brain and their function
• Frontal lobe –consciousness, speech production, movement
• Parietal lobe –perception
• Occipital lobe –vision
• Temporal lobe– speech recognition, hearing
Localisation of function
Specific functions of the brain have specific locations in the brain
specific areas of the cerebral cortex are associated with particular physical and psychological functions
Phineas gage – First patient from whom we learned something about the relation between personality and the function of the front parts of the brain
– Phineas Gage was the foreman of a railway construction gang. On September 13, 1848, an accidental explosion of a charge he had set blew his tamping iron through his head.
– The tamping iron was 3 feet 7 inches long and weighed 13 1/2 pounds. The tamping iron went in point first under his left cheek bone and completely out through the top of his head, landing about 25 to 30 yards behind him.
Motor cortex
Responsible for generation of voluntary motor movements
. Located in frontal lobe along the bumpy region (!) the precentral gyrus
. On both hemispheres – motor cortex on right hemisphere controlling muscles on left side of body and vice versa
. Damage to this area may result in loss of control over fine movements
. Different parts of the motor cortex control different parts of the body
. These are arranged logically – the region that controls the foot is next to the region that controls the leg
Somatosensory cortex
Detects sensory events from different regions of the body
. In parietal lobe, separated from the motor area by the ’valley’ called central sulcus
. Dedicated to the processing of sensory info related to touch; different areas of the body have more receptors than others making them more sensitive such as the skin.
. Uses sensory info from skin to produce sensations such as touch pressure, pain, temperature which it then localises to specific body regions
. The amount of somatosensory area devoted to a particular body part denotes its sensitivity. For example receptors in our face and hands occupy over half of the somatosensory area.
. Both hemispheres have a somatosensory cortex
. The cortex on one side of the brain receives sensory info from the opposite side of the body
Visual centre
Located in the visual cortex in the occipital lobe
. Visual processing begins in retina (light enters and strikes the photoreceptors (rods and cones))
. Nerve impulses from the retina travel to areas of the brain via the optic nerve
. Some travel to areas of the brain involved in coordination of circadian rhythms
. Most terminate in the thalamus, this acts as a relay station passing info to visual cortex
. Each eye sends information from the right visual field to the left visual cortex and from the left visual field to the right visual cortex. This means damage to the left hemisphere can produce blindness in the right visual field of both eyes.
. Visual cortex contains different areas that process different types of visual info such as colour, shape and movement.
Auditory centre
In temporal lobes on both sides of brain
2. Begins in cochlea in inner ear, sound waves are converted to nerve impulses
3. These travel via the auditory nerve to the auditory cortex
4. Pit stop at the brain stem where basic decoding happens .Then on to thalamus which acts as a relay station and carries out further processing of auditory stimulus
5. Last stop is at the auditory cortex
6. Sound has already been largely decoded by this point, in the auditory cortex it is recognised and may result in an appropriate response.
7. Damage may produce partial hearing loss; the more extensive the damage, the more extensive the hearing loss
Karl lashley
• Higher cognitive functions such as processes involved in learning, are not localised but distributed in a more holistic way in the brain.
• No matter what part of the cortex was removed, rats kept at least partial memory of the maze.
• Lashley concluded that memory did not lie in specific parts of the brain, or resides in a number of locations within the cortex, or maybe outside of the cortex completely.
• No area was proven to be more important than any other.
• Suggest learning is more complex to be localised and that learning requires all the
areas of the cortex.
• Lashley claimed “The apparent capacity of any intact part of a functional brain to carry out… the [memory] functions which are lost by the destruction of [other parts]” … Equipotentiality is subject to the other term Lashley coined, the law of mass action.
Broca’s area
an area of the frontal lobe of the brain in the left hemisphere (in most people) responsible for speech production.
Wernicke’s area
an area of the temporal lobe (encircling the auditory cortex) in the left hemisphere (in most people) responsible for language comprehension
Tan
Dronkers et al. (2007) conducted an MRI scan on Tan’s brain, to try to confirm Broca’s findings. Although there was a lesion found in Broca’s area, they also found evidence to suggest other areas may have contributed to the failure in speech production.
• These results suggest that the Broca’s area may not be the only region responsible for speech production and the deficits found in patients with Broca’s aphasia could be the result of damage to other neighbouring regions.
