Hippocampus

Question 1

Episodic memory

Answer 1

Episodes have a spatiotemporal context.

Question 2

Neurons in rat HC

Answer 2

Place cells. A cognitive map (encodes where the rat in within the environment).

Question 3

Morris et al. (1982) watermaze task rats with HC lesions

Answer 3

Rats with HC lesions took longer to find the platform when it was hidden under opaque water (place navigation) but not when platform was visible (cue navigation). Specifically spatial navigation impaired by HC lesions.

Question 4

Olton and Papas (1979) 8-arm radial maze spatial reference memory vs. spatial working memory rats with fornix transections

Answer 4

Rats with fornix transections made more working memory errors but not reference memory errors. HC not for learning fixed things in space, but for learning about changes in spatial relationships.

Question 5

Wood et al. (1999) delayed non-match odour dig task rats HC neuron recording

Answer 5

Dig if the current odour does not match the previous odour. HC neurons encoded both spatial and non-spatial information (‘a global record of memory’ - eg. also temporal information).

Question 6

Fortin et al. (2002) rats learning odour sequences task recognition vs. sequential order trials

Answer 6

HC lesions impaired sequential order task (bad at selecting which was presented first) but not impaired at recognition task.

HC needed for non-spatial sequential memory.

Question 7

Neurons in NHP HC

Answer 7

Spatial-view cells. Encode where animal is looking, not where it currently is.

Question 8

NHP neurotoxic lesions object-object associative memory and scene learning

Answer 8

Associative learning about objects not impaired. Scene learning impaired.

Question 9

2 tasks impaired by macaque fornix transection

Answer 9

1. Object-in-scene learning. Contextual learning: correct object depends on scene. (Gaffan, 1994).
2. Recency memory (but not simple recognition; Charles et al., 2004).

Question 10

Neurons in human HC

Answer 10

Could be either place cell or spatial-view cell (being in a specific place would have a certain view).

Question 11

Taylor et al. (2007) recognition memory test for faces and scenes in humans with MTL damage

Answer 11

Patients with broad damage to MTL structures (includes HC + PRh) impaired on both face and scene memory. Patients with damage limited to HC showed deficits only in scene memory.

Question 12

Lehn et al. (2009) temporal sequence task in humans either retrieve (no logical order) or infer (no need for sequence memory)

Answer 12

Greater HC activity for retrieve trials than infer trials. Degree of HC signal change correlates with accuracy of sequence memory recall.

Question 13

Parts of MTL damage in HM

Answer 13

1. Hippocampus.
2. Amygdala.
3. Anterior temporal stem.

Three indirect routes from temporal lobe cortex to frontal lobe cortex via basal forebrain compromised. Explanation for HM’s dense amnesia?

Question 14

Spiers et al. (2001) patient Jon hippocampal damage VR town memory impairments

Answer 14

Impaired topographical memory (drawing maps and navigation) and episodic memory (could not recall where/when/from whom objects were obtained).

Not impaired on object/scene recognition.

Question 15

Rempel-Clower et al. (1996) patient GD ischemic hippocampal CA1 damage

Answer 15

Reletively selective, but still had other damage (eg. left fornix and right thalamus).

Question 16

Lee et al. (2006) SD and AD in face/scenes oddity task

Answer 16

Functional double dissociation. AD: higher percentage error in scene different. SD: higher percentage error in face different.

1. MTL is not functionally homogenous (SD and AD have different damage in MTL).
2. MTL structures also needed for perceptual discrimination.

Question 17

Representational hierarchy theory HC

Answer 17

PRh -> ERh -> HC. HC may be for objects within places. Combine inputs.

Question 18

Lee et al. (2005) HC damage face/scene oddity task

Answer 18

HC patients had a high error rate for ‘scene different’ but not ‘face different’ condition. Scene perceptual discrimination impaired.

Question 19

Maguire et al. (1998) HC in virtual town navigation

Answer 19

PET scan. HC needed for active navigation (magnitude of right HC activity correlated with accuracy). Controls had arrows to follow.

Question 20

Eichenbaum et al. (1999) cognitive mapping/relational memory hypothesis of hippocampal function

Answer 20

Both mapping and memory are formed through a relational network. HC builds up sequential representations of environment (spatial) or episodes (temporal).

Question 21

Tulving (2002) definition of episodic memory

Answer 21

Autonoetic awareness of one’s experiences in the continuity of subjectively apprehended time that extends both backwards into the past (in the form of ‘remembering’) and forward into the future (in the form of ‘thinking about’ or imagining or ‘planning for’ the future).

Question 22

Magiure and Mummery (1999) HC activity for personal relevance and temporal specificity of memories

Answer 22

Left HC activated specifically for autobiographical events (personally relevant and temporally specific memories).

Question 23

Aggleton and Brown (2006) doors and peoples test for HC/fornix lesions

Answer 23

Spared recognition/familiarity, impaired recall.

Question 24

Montaldi et al. (2006) HC in remember/know paradigm for familiarity/recollection

Answer 24

Greater response in left and right HC to recollected vs. strongly familiar scenes.

Question 25

Wheeler and Stuss (2003) remember/know task in frontal lobe injuries

Answer 25

Frontopolar lesions. Impaired episodic remembering (recollection) but not knowing.

Question 26

Habib et al. (2003) HERA PFC

Answer 26

Hemispheric encoding/retrieval asymmetry model. Left PFC more involved in EM encoding, right PFC more EM retrieval.

Question 27

Ecphory definition

Answer 27

Recovery of stored information.

Question 28

REMO definition

Answer 28

A remembering state of mind, irrespective of whether retrieval is successful.

Question 29

Lepage et al. (2000) REMO regions

Answer 29

Right PFC more active when trying to retrieve episodic info (irrespective of successful ecphory). Includes frontopolar cortex.

Question 30

Volle et al. (2010) prospective memory paradigm voxel-by-voxel lesion mapping method

Answer 30

Voxels with FPC lesions correlated the most with time-based prospective memory deficits (future intention). Ongoing task and prospective memory task.

Question 31

Components of delay-brion circuit

Answer 31

1. HC. 2. Fornix. 3. Mammillary bodies. 4. Mammillo-thalamic tract. 5. Anterior thalamus. 6. Cingulate gyrus. 7. Retrosplenial cortex. 8. ERh. And then back to HC.

Question 32

Aggleton et al. (2000) human fornix transections

Answer 32

Not impaired on object recognition (matching-to-sample task). Impaired scene learning (object-in-place scene learning task).

Question 33

Gaffan (1994) impact of fornix transection in object-in-scene discrimination learning task

Answer 33

Impairs object-in-scene discrimination learning but no dense amnesia (performance is still better than chance).

Question 34

What does the diencephalon contain? Where is it?

Answer 34

Forebrain. Contains thalamus and hyypothalamus.

Question 35

What are the mammillary bodies?

Answer 35

Hypothalamic nuclei. Located at ends of anterior arches of fornix.

Question 36

Dusoir et al. (1990) patient BJ snooker cue damage

Answer 36

Mammillary body damage. Marked anterograde amnesia, no retrograde amnesia. Intact recognition. Mammillary bodies for new learning?

Question 37

Tsivilis et al. (2008) colloidal cyst patients reduced mammilary body volume recall vs. recognition

Answer 37

Extent of mammillary body atrophy more strongly correlated with performance in recall than recognition. HC volume did not correlate with either performance measure in this study.

Question 38

Aggleton and Brown (1999) episodic recollection system

Answer 38

Extended hippocampal-diencephalic system (including delay-brion).

Question 39

Aggleton and Brown (1999) familiarity-based item recognition system

Answer 39

PRh and medio-dorsal thalamic nucleus system.

Question 40

Parker and Gaffan (1997) macaque anterior thalamic lesions object-in-scene learning

Answer 40

Impaired.

Question 41

Parker and Gaffan (1997) cingulate cortex lesions object-in-scene learning

Answer 41

Not impaired. Lack of impairment may be because there are other routes back to MTL other than cingulate cortex (eg. via PFC). Most regions of anterior thalamus degenerate after cingulate lesions but not anterior medial nucleus (with PFC projections).

Question 42

Rodent retrosplenial cortex lesions task impairment

Answer 42

1. Watermaze and object-in-place impaired. 2. Object recognition memory not impaired. Spatial tasks impaired.

Question 43

Macaque retrosplenial cortex lesions task impairment

Answer 43

Object-in-scene memory not impaired.

Question 44

Rodent object-in-place vs. macaque object-in-scene

Answer 44

Rodent version requires animal to physically move around within place. Macaque version animal keeps still but moves eye-gaze across scene. Maybe retrosplenial cortex for egocentric not allocentric memory?

Question 45

Vann et al. (2009) function of retrosplenial cortex

Answer 45

Translation between egocentric and allocentric representations.

Question 46

Uncinate fascicle

Answer 46

Fibre pathway between frontal and temporal lobe. Cutting this pathway leads to memory impairments.

Question 47

3 connections between basal forebrain and temporal lobe cortex (indirect routes)

Answer 47

Amygdala, anterior temporal stem, fornix.

Question 48

Gaffan et al. (2001) triple lesion object-in-scene discrimination learning

Answer 48

Dense amnesia after amygdala, anterior temporal stem section, and fornix transection (MTL still intact!).

Question 49

Crossed unilateral asymmetrical lesions PFC and MTL

Answer 49

Impairs interaction between 2 brain areas. Interaction required for representations of a linked series of events that are sufficiently temporally complex.

Question 50

Rival explanation to delay-brion circuit

Answer 50

Mediodorsal thalamic nuclei (strong reciprocal interactions with PFC and only light projections from MTL). Lesions also impair object-in-scene learning task.

Question 51

1TPORT impairments mediodorsal thalamic nucleus and fornix transection

Answer 51

Both result in anterograde but not retrograde amnesia. Selective subcortical damage appears to result in greater anterograde than retrograde memory loss.

Question 52

Which lesions result in more severe retrograde amnesia than anterograde amnesia?

Answer 52

Selective cortical lesions (eg. retrosplenial cortex and PRh). Impair retention of problems learnt pre-operatively more than learning of new problems post-operatively.

Question 53

Explanations for HM's amnesia

Answer 53

1. Damage to MTL cortex. 2. Direct damage to subcortical structures or damage to connections with cortex.