section 11.7 Flashcards
Lesions to particular structures tend to produce either
no retrograde amnesia at all or retrograde amnesia for only the experiences that occurred in the days or weeks just before the surgery. Lead to two major conclusions:
- Memories are stored diffusely in the brain and thus can survive destruction of any single structure.
- Memories become more resistant to disruption over time.
Four neural structure that appear to play some role in the storage of memories
the (1) hippocampus and (2) the medial temporal cortex have roles in episodic memory; and (3) the mediodorsal nucleus and (4) the basal forebrain have been implicated in memory by Korsakoff’s and Alzheimer’s disease, respectively.
Areas of the brain that are active during the retention of an experience tend
to be the same ones active during the original experience.
inferotemporal cortex
cortex on the inferior temporal cortex, which has complex visual functions.
Bussey and Saksida
argued that the inferior temporal cortex, in concert with adjacent perirhinal cortex, plays an important role in storing memories of visual input.
Naya, Yoshida, and Miyashita
recorded the responses of neurons in the inferotemporal cortex and perirhinal cortex while monkeys learned the relation between the two items in pairs of visual images. When a pair was presented, responses were first recorded in the inferoteporal neurons and then in perirhinal neurons; however, when the monkeys were required to recall that pair, activity was recorded in perirhinal neurons before inferotemporal neurons. Condluded that this reversed pattern of activity reflected the retrieval of visual memories from inferotemporal cortex.
amygdala
plays a special role in memory for the emotional significance of experiences. Little evidence for storing memories; it appears to be involved in strengthening emotionally significant memories stored in other structures.
prefrontal cortex
the area of frontal cortex anterior to motor cortex. Large structure that is composed of many anatomically distinct areas that have different connections, and presumably, different functions.
Patients with damage to the prefrontal cortex are not
grossly amnesic; they often display no deficits at all on conventional tests of memory.
Stuss and Alexander
argued that different parts of the prefrontal cortex play different roles in memory.
Patients with large prefrontal lesions often display both
anterograde and retrograde deficits in memory for the temporal order of events, even they can remember the events themselves. Also display deficits in working memory. As a result, patients with prefrontal cortex damage often have difficulty performing tasks that involve a series of responses.
Some regions of the prefrontal cortex perform fundamental
cognitive processes (e.g., attention and task management) during working memory tasks, and other regions seem to participate in other memory processes.
Explicit memories are presumed to be stored in the
circuits of the brain that mediated their original perception.
Implicit memories of sensorimotor learning are presumed to be stored
sensorimotor circuits.
cerebellum
thought to participate in the storage of memories of learned sensorimotor skills through its various neuroplastic mechanisms.
