Raymond P. Kesner, Bridget L. Bolland, Manoli Dakis

Group A7: Snir Seitelbach, Dave Dudar, Scott Good, Katie Herdman, Monika Walerjan

Memory for Spatial Locations, Motor Memory for Spatial Locations, Motor Responses, and Objects: Triple Responses, and Objects: Triple

Dissociation among the Hippocampus, Dissociation among the Hippocampus, Caudate Nucleus, and Extrastriate Caudate Nucleus, and Extrastriate

Visual CortexVisual Cortex

OUTLINEINTRODUCTION

Overall Motive of the Experiment Background

Inadequate Research Adequate Research

METHOD Pros Cons

RESULTS & DISCUSSION CRITIQUES Hippocampus Lesions Caudate Nucleus Lesions Extrastriate Visual Cortex Lesions

NEXT STEPSREFERENCES

INTRODUCTIONOverall Motive of the Experiment

To prove there are multiple memory systems

Attribute Database Memory Model

Working & Declarative Memory

Model

Different neural substrates that mediate different attributes

Hippocampus exclusively codes all information (spatial, temporal, response, sensory-perceptual, or affect)

Snir Seitelbach

BACKGROUND Inadequate Research

“Equivalent impairment of spatial and nonspatial memory following damage to the hippocampus”

- Cave and Squire

• Our study claimed Cave and Squire thought humans with demonstrated hippocampal damage show deficits in spatial memory tasks

• Conclusion of study above: Hippocampus is not especially involved in spatial memory

Snir Seitelbach

BACKGROUND Inadequate Research

“A note on spatial-motor deficits in patients with Huntington’s disease: a test of a hypothesis”

- Potegal

In Our Study: labeled as a deficit in memory.Health Canada defines Huntington’s disease

as a neuronal degeneration disorder that involves functional deficit.

Snir Seitelbach

BACKGROUND Adequate Research

“Limbic lesions and the problem of stimulus-reinforcement associations”

- Jones & Mishkin

Hippocampal lesions in monkeys produce severe deficits in spatial location memory tasks

Snir Seitelbach

BACKGROUND Adequate Research

“The contributions of positions, direction and velocity to single unit activity in the hippocampus of freely moving rats”

- McNaughton, Barnes, & O’Keefe

In both monkeys and rodents many hippocampi cells increase their firing rate when an animal is located a specific place within a specific environment or is attempting to locate a stimulus in a particular location

Snir Seitelbach

METHOD

EXPERIMENT 1 EXPERIMENT 2 EXPERIMENT 3

Spatial Location Memory Task

Motor Response Memory Task

Visual Object Memory Task

Katie Herdman

METHODPros

The radial arm maze in Experiment 1 is an adequate method for testing spatial location memory as established by previous studies.Modification of Experiment 3 to allow for

direct comparisons with the same analogous procedures used in monkeys.

Katie Herdman

METHODPros

Verification of lesions to show consistent damage across all three experiments.

Katie Herdman

METHODCons

Sample size was small for each lesioned groups in each experiment.

The sample size was not the same for all lesioned groups.

Katie Herdman

METHODCons

Lesion verification showed damage to primary striate visual cortex, affecting rat’s vision during Experiment 3.

Katie Herdman

The Primary Visual Cortex

V1 is uniquely positioned as the primary distributor of most visual information that reaches other cortical areas

In absence of V1, visual signals still reach many extrastriate areas, but seem incapable of generating normal conscious experiences

(Tong, 2003)

Katie Herdman

METHODCons

Acid lesioning may be more preferable instead of electrolytic lesioning because it is more accurate

Kainic Acid

Katie Herdman

A Different Method for Lesioning

“In situ injection of kainic acid: a new method for selectively lesioning neural cell bodies while sparing axons of passage”

- Coyle, Molliver & KuharThese morphologic studies provide direct

evidence that injection of kainic acid in brain causes a selective degeneration of neurons will cell bodies in the area of the injection but spares axons that pass through or terminate in the injected area.

(Coyle et al., 1978)

Katie Herdman

RESULTS & DISCUSSION Critiques

Hippocampal Lesions: Mice unable to perform well in spatial memory tasks, but performed well on the other tasks.

This supports the attribute model.

Scott Good

RESULTS & DISCUSSION Critiques

Hippocampal Lesions: A recent study made an observation on the hippocampus’ function: it is only responsible for spatial memory.

This is a large generalization.

Scott Good

RESULTS & DISCUSSION Critiques

Hippocampal Lesions: the hippocampus is responsible for processing memory.

The rats were retested seconds-to-minutes after the learning process.

A longer wait would have showed deficits in all the experimental procedures.

Scott Good

RESULTS & DISCUSSION Critiques

Caudate Nucleus Lesions: responding do a visual stimulus requires egocentric knowledge of the location of the stimulus.

Many cells responsible for this cognitive ‘roadmap’ are found in the posterior parietal cortex, but this was not addressed.

Scott Good

RESULTS & DISCUSSION Critiques

Caudate Nucleus Lesions: Cells in the caudate nucleus respond to other stimuli such as smell, sound and sight.

Lesions in the caudate nucleus would affect these senses, most importantly the rat’s ability to see to respond.

Scott Good

RESULTS & DISCUSSION Critiques

Extrastriate Visual Cortex Lesions: mice had difficulty in non-matching to sample tasks

Evidence supports the attribute model

Scott Good

RESULTS & DISCUSSION Critiques

Extrastriate Visual Cortex Lesions: object recognition test should have had controls

Comparison to apperceptive agnosia is confusing

Role of hippocampus may have been underestimated for long term memory formation (Squire & Zola-Morgan, 1991)

Scott Good

NEXT STEPS…Less bias toward one specific model (Kessner

is the author of the study and the creator of the attribute model…hmmmm?)

A much larger sample size: study did not have a lot of power

More accurate lesioningMore scientific method for object-

discrimination task.

Snir Seitelbach

REFERENCES Cave, C.B. & Squire, L.R. (1991). Equivalent impairment of spatial and nonspatial memory

following damage to the human hippocampus. Hippocampus 1: 329-340. Coyle, J.T., Molliver, M.E., & Kuhar, M.J. (1978). In situ injection of kainic acid: a new method

for selectively lesioning neural cell bodies while sparing axons of passage. J Comp Neurol. 180 (2): 301-323

Firth, C. D. (2000). Abnormalities in the Awareness and Control of Action. Biological Sciences. 355 (1404): 1771-1788.

Howell, D. (2008). Fundamental Statistics for the Behavioural Sciences. Belmont, CA : Thomson/Wadsworth, 6th ed.

Jones, B. & Mishkin, M. (1972). Limbic lesions and the problem of stimulus reinforcement associations. Exp Neurol 36: 362-377.

McNaughton, B.L., Barnes, C.A., O’Keefe, J. (1983). The contribution of position, direction and velocity to single unit activity in the hippocampus of freely moving rats. Exp Brain Res 52: 41-49.

Milner, A. D. et. al. (1999). A Paradoxical Improvement of Misreaching in Optic Ataxia: New Evidence for Two Separate Neural Visual Systems for Visual Localization. Biological Sciences. 266 (1434): 2225-2229.

Squire, L.R. & Zola-Morgan, S. (1991). The medial temporal lobe memory system. Science. 253: 1380-1386.

Tong, F. (2003). Primary Visual Cortex and Visual Awareness. Neuroscience. 4, 219-229.

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