Frontal lobes and hippocampus

Question 1

Lesions at DLPFC

Answer 1

Perseveration, environmental dependency (can’t focus attention –> require environmental cues to accomplish tasks)

Question 2

Lesions at VMPFC

Answer 2

Characteristic Iowa Gambling Task performance (continue to draw from “bad” decks). Fail to show stress responses from bad decks.

disinhibition of aggression, sexual behavior, anxiety, appetitive functions

Question 3

Lesions at the anterior cingulate cortex

Answer 3

abulia (lack of will) = patients able to follow conversations, but feel no will to respond to questions.

deficits of focused mental effort

Question 4

executive function of DLPFC

Answer 4

intention and attention

Question 5

executive function of VMPFC

Answer 5

positive and negative valence of stimuli, computing potential gains and losses of potential actions (with amygdala, ventral striatum and nucleus accumbens input)

Question 6

executive function of anterior cingulate cortex

Answer 6

detection of conflicts between current attention or behavior and desired results –> motivation

Question 7

hippocampus function

Answer 7

formation of long-term memory, memory “search engine”

nearly all hippocampal functions are performed in collaboration with several of its partners and strongly influenced by subcortical neuromodulators

Question 8

Bilateral hippocampal dysfunction

Answer 8

Patient HM. deficits in declarative memory, spatial memory, episodic memory

Question 9

Place cells

Answer 9

cells in hippocampus that fire when you are in a certain “place” in space

Question 10

grid cells

Answer 10

cells in entorhinal cortex that encode a cognitive representation of Euclidian space –> dynamic computation of self-position

Question 11

3 regions of hippocampal formation

Answer 11

dentate gyrus, hippocampus (aka Ammon’s horn), subiculum (zone between hippocampus and entorhinal cortex)

Question 12

hippocampus location

Answer 12

body extends caudally along the inferior horn of the lateral ventricle

Question 13

major cell types of dentate gyrus

Answer 13

granule cells, inhibitory interneurons

Question 14

major cell types of the hippocampus

Answer 14

pyramidal cells, inhibitory interneurons

Question 15

CA 3

Answer 15

adjacent to dentate, extending through the opening of the dentate

Question 16

CA 1

Answer 16

merges with the subiculum

Question 17

Two major inputs to the hippocampal formation

Answer 17

entorhinal cortex and septal nuclei

Question 18

“trisynaptic circuit” through the hippocampal formation

Answer 18

entorhinal cortex –> dentate gyrus –> granule cells –> CA 3 of hippocampus –> pyramidal cells –> CA 1 and fornix.

CA1 –> subiculum –> entorhinal cortex –> cortical association areas

Question 19

Perforant path

Answer 19

major projection from entorhinal cortex to dentate gyrus and hippocampus

Question 20

Mossy fibers

Answer 20

axons of granule cells –> CA 3

Question 21

Schaeffer collaterals

Answer 21

axons from CA 3 to CA 1

Question 22

Autoassociative memory

Answer 22

neural network that enables you to retrieve entire memories from only a tiny sample of itself

“A day that will live in ____”

Question 23

Memory consolidation

Answer 23

interaction between hippocampus and neocortex during sleep

representations of recent experiences are transferred from hippocampus to neocortex –> long-term memories

Question 24

Standard model of memory consolidation

Answer 24

novel info is originally recorded and registered –> memory retention in both hippocampal and cortical regions –> hippocampus’ representations become active in recall during wake or sleep

Question 25

Assumptions of Standard model of memory consolidation

Answer 25

hippocampus rapidly and automatically acquires information, is a limited capacity storage system (rapid forgetting), transfers info to be permanently stored in cortex, plays a critical role in the genesis of cortical memories

Question 26

How long is memory retained in the hippocampus?

Answer 26

one week after initial learning

Question 27

How does a memory become hippocampus independent

Answer 27

information is recalled –> strengthening of cortico-cotical connection –> slow transferring of info to neocortex –> permanent storage