Ch 11, 12, 13 Flashcards
what are four variables that complicate research on laterality?
- laterality is relative, not absolute
- cerebral site is at least as important in understanding brain function as cerebral side
- environmental and genetic factors affect laterality
- a range of animals exhibit laterality
laterality
the idea that the two cerebral hemispheres have separate functions
planum temporale
Wernicke’s area
primary auditory cortex
Heschl’s gyrus
Sylvian fissure
lateral fissure
double dissociation
two neocortical areas are functionally dissociated by two behavioural tests, performance on each test is affected by a lesion in one zone but not in the other
commissurotomy
the surgical procedure of disconnecting the two hemispheres (by cutting the fibers of the corpus callosum)
split brains
separated cortexes
what are the 4 general effects of applying electrical current to the cortex of a conscious patient?
- the brain has symmetrical as well as asymmetrical functions
- the right hemisphere has perceptual functions not shared by the left hemisphere
- stimulating the left frontal or temporal region may accelerate speech production
- stimulation blocks function
dichotic-listening tasks
two different sounds are presented simultaneously to each ear, usually the contralateral pathway is preferred
dichaptic test
participants feel objects, then look at an array of objects and select those that they previously touched
apraxia
severe deficits in making or copying voluntary movement sequences
what are 3 versions of the interaction models (both hemispheres have the capacity to perform all functions but do not):
- the two hemispheres function simultaneously but work on different aspects of processing
- although the two hemispheres have the capacity to perform a given function, they inhibit or suppress each other’s activity
- either the two hemispheres receive info preferentially and thus perform different analyses simultaneously or some mechanism enables each hemisphere to pay attention to specific types of info, thus leading to different hemispheric analyses
preferred cognitive mode
refers to the use of one type of thought process in preference to another
what are two types of lesion-related differences between male and female brains?
- degree of asymmetry in the lesion effects
2. intrahemispheric organization
superior temporal sulcus (STS)
a multimodal cortex, target of one of the visual streams
dorsal visual stream
parietal pathway; participates in the visual guidance of movement
ventral visual stream
includes both the inferior temporal pathway and the STS pathway, concerned with object perception (including colour and faces) and perceiving certain types of movements
dynamic form
the shape of objects in motion
egocentric space
the location of objects relative to an individual
allocentric space
the location of objects relative to one another
the argument that the dorsal stream is for online visual control of action based on 3 lines of evidence:
- visual neurons in posterior parietal regions are unique in that they are active only when the brain acts on visual information
- visual posterior parietal neurons therefore act as an interface between analysis of the visual world and motor action taken on it
- most visual impairments associated with lesions to the parietal cortex can be characterized as visuomotor or visuospatial
polysensory neurons
neurons responsive to both visual and auditory or both visual and somatosensory input
bitemporal hemianopia
loss of vision of both temporal fields
