4THE NEURAL BASIS OF ANIMAL COGNITION
INTRODUCTION – Elie El Rassi
Course Overview
• 6 Lectures: Spatial representations, Replay, Memory development, Semantic memory,
Stress and memory -> Closed book exam with short essay questions - 4 April (50%, must
pass)
• Reading material = primary research articles (discusses in individual lectures)
• Journal Club -> Presentations 15% and active participation during presentation 5% (have to
read the other papers presented -> you either get full or no points)
• Present a recent paper in the field that you think is
interesting
• Treat it like any other presentation – i.e. it needs an
introduction, a methods section, results, etc.
• Comment on rigor of methods, results and
interpretation
• Group with two others -> Let me know (at the latest)
one week before the scheduled JC what article you
have chosen
• On the weeks where you are not presenting you still
have to read *one* of the papers assigned that week
• If you are not presenting, you still need to participate in the presentation discussion
• Review paper 2 june (30%)
• Short (~1500 words) review article on a recent paper
• Journal of Neuroscience Journal Club
• Review should cover the following:
▪ Why the authors carried out their study?
▪ What do we already know about the topic?
▪ What question did the study answer?
▪ What are the results?
▪ How do the results relate to other results in the field?
▪ What are the implications for research and society?
• Example journal clubs: https://www.jneurosci.org/content/by/section/Journal+Club
• More information about requirements and format:
https://www.jneurosci.org/content/jneurosci-journal-club
Learning outcomes
• Describe the different forms of memory and compare and contrast their function and
neural substrates.
• Explain the function of different spatial cell types in the hippocampal formation.
• Describe the phenomenon of hippocampal replay and explain its hypothetical function in
memory retrieval and maintenance processes.
• Describe the principal milestones of memory development and explain how studying
memory may give insight into the operations of the memory system in adulthood.
• List key molecular/genetic candidates implicated in memory function and describe
dominant theories about the molecular mechanisms supporting memory formation.
• Describe evidence showing how stress affects memory and explain influential theories of
anxiety disorders (such as post-traumatic stress disorder, PTSD).
,• Critically evaluate research articles in the field of (animal) memory research and give a clear
and coherent presentation of it to peers.
• Constructively participate in discussions about the methods and findings of a research
article (e.g. by asking relevant questions at appropriate times, engaging in discussions with
others about the article, etc.)
• Write a short (~1500 words) review article based on recently published findings.
Neural basis of cognition: overview
Neural systems of memory
• Two broad memory categories: implicit
(nondeclarative) and explicit (declarative) memory
• Two memory ‘systems’ subserved by distinct brain
regions
• Simply, implicit memory relates to knowledge we
acquire un-sub-consciously while explicit memory
relates to knowledge we acquire consciously
o Remember how to ride your bike is an example of
implicit memory whereas knowing what you had
for breakfast this morning is a type of explicit
memory
o Implicit memory is memorizing skills, habits,
conditioning and reflexes, while explicit memory
is episodic and semantic
o Episodic memory involves the ability to learn, store, and retrieve information about
unique personal experiences that occur in daily life. It is hard to know to be sure you are
studying episodic memory in non-verbal animals. We much often study spatial memory.
o Sematic memory involves memory of facts. You can’t recall the event, but you just
know, so impossible to study in animals
Neural systems of memory: Implicit memory
• Patients suffering from hippocampal amnesia can recall recently
learned words if they are primed with the first 3 letters of the word,
otherwise not
o This type of memory doesn’t rely on hippocampus but on cortex
• Hippocampal patients can also acquire a new skill – learning to
trace a star while viewing hand through mirror
o Skill motor learning not dependent on the hippocampus, but on
for example basal ganglia and cerebellum
-> The hippocampus is essential for explicit/declarative memory (such as conscious recall), but
not for implicit forms of memory such as priming and procedural learning.
Neural systems of memory: Explicit memory
• Explicit memory involves four operations:
o Encoding (memory formation)
o Consolidation (strengthening of a new memory)
o Storage
o Retrieval
• Explicit memory involves an interaction between the hippocampus and cortical regions
• Episodic (memory of events) and semantic (knowledge of facts) memories are two types
explicit memory
,• While implicit learning takes time (but then you know it without thinking), explicit learning is
quite fast, but always requires conscious
Neural systems of memory: Explicit memory – Patient H.M.
• Patient H.M suffered severe temporal lobe epilepsy
• His hippocampi were bilaterally removed to try to alleviate his epileptic systems
• Following his surgery H.M suffered anterograde amnesia (could not form new memories)
and temporally graded retrograde amnesia (could not recall his recent past)
• But he could still remember old memories!
-> Hippocampus plays a role in consolidation of memories but not in storage or retrieval ->
Memory is stored somewhere else, probably the cortex
Neural systems of memory: explicit memory – Evidence in rodents
• Rats were trained on a contextual fear-conditioning paradigm – they
received a foot shock in a particular environment
• The hippocampus was lesioned at varying intervals following training
• Animals who’s hippocampus was earlier lesioned after training
showed less freezing (so accurate recall) then animals where the
hippocampus was later lesioned
• The hippocampus is required for memory encoding and
consolidation, but not for storage
Neural systems of memory: explicit memory – Semantic memories
• Semantic memory, on the other hand, is thought to rely on cortical circuits.
• However, semantic memory formation is thought to require the
hippocampus – patient H.M. could not acquire new knowledge (semantic
explicit memory).
• Once semantic memories are ‘made’ they can be recalled without the
involvement of the hippocampus.
Semantic memories to semantic categories
• Semantic memories are structured into semantic categories, which are context-
dependent and flexible -> Boundaries are not fixed
• For example, a cat belongs to the category "cat," but categories can have different
dimensions such as size. A cat may be considered big compared to a smaller cat
but small compared to a lion. This shows how categorization depends on context.
• Semantic categories are flexible and can change as we learn new information. When
encountering a new animal, we might adjust our existing categories or create a new one
-> This demonstrates that category boundaries shift dynamically based on experience and
learning.
Semantic categories: face or vase?
• The ventral visual pathway or ventral stream
(visual cortex through temporal lobe) is
involved in visual object categorization in
humans and monkeys -> ‘What’ pathway
o Increased connectivity of ventral stream
• Increased connectivity of FFA when people saw face
instead of
vase
, Neural-circuit and molecular mechanisms of memory
• At the circuit level memory is thought to be underpinned by
changes in synaptic connectivity - long-term potentiation
(LTP)
• If pre-synaptic cell fires reliably before post-synaptic cell, and
it does so at a high enough rate than the synapse will undergo
strengthening such that a future action potential from the pre-
synaptic cell is more likely to evoke a response in the post-
synaptic cell than before LTP induction
• LTP has been investigated most extensively at hippocampal
synapses (Schaffer collaterals).
Spike-timing-dependent-plasticity (STDP)
• Synaptic plasticity may be mediated by precise spike-time
synchronization of pre- and post-synaptic cells
• If pre-synaptic cell fires just (<20ms) before post-synaptic cell, long-
term potentiation (LTP) occurs
• If post-synaptic cell fires just before pre-synaptic cell, long-term
depression (LTD) occurs
• If more than 100ms separate activity from two cells, no plasticity
occurs
Animal models in cognitive neuroscience
Animal models: rodents
• Rodents are used in behavioral tests because they have well-
characterized neural circuits, share cognitive and genetic
similarities with humans, and allow controlled, reproducible
experiments on learning and memory.
• Radial Arm Maze: A behavioral task in which rodents
navigate a maze with multiple arms to find food rewards,
testing spatial memory and hippocampal function.
• Morris Water Maze: A spatial learning task where rodents must locate a hidden platform in
a water-filled pool using distal environmental cues, relying on hippocampal-dependent
navigation.
• Contextual Fear Conditioning: A learning paradigm where rodents associate a specific
environment with an aversive stimulus (e.g., a foot shock), assessing hippocampus-
dependent memory formation.
Use rodents to study place and grid cells
• Place cells: type of neuron in the hippocampus that
fires when an animal is in a specific location within its
environment, effectively forming a spatial map in the
brain. These cells play a crucial role in spatial
navigation and memory formation.
• Grid cells: found in the entorhinal cortex. Grid cells
fire in a hexagonal pattern as the animal moves, providing a coordinate system that helps
with spatial navigation and path integration
• Together, place cells and grid cells form the foundation of the brain’s internal GPS system.
INTRODUCTION – Elie El Rassi
Course Overview
• 6 Lectures: Spatial representations, Replay, Memory development, Semantic memory,
Stress and memory -> Closed book exam with short essay questions - 4 April (50%, must
pass)
• Reading material = primary research articles (discusses in individual lectures)
• Journal Club -> Presentations 15% and active participation during presentation 5% (have to
read the other papers presented -> you either get full or no points)
• Present a recent paper in the field that you think is
interesting
• Treat it like any other presentation – i.e. it needs an
introduction, a methods section, results, etc.
• Comment on rigor of methods, results and
interpretation
• Group with two others -> Let me know (at the latest)
one week before the scheduled JC what article you
have chosen
• On the weeks where you are not presenting you still
have to read *one* of the papers assigned that week
• If you are not presenting, you still need to participate in the presentation discussion
• Review paper 2 june (30%)
• Short (~1500 words) review article on a recent paper
• Journal of Neuroscience Journal Club
• Review should cover the following:
▪ Why the authors carried out their study?
▪ What do we already know about the topic?
▪ What question did the study answer?
▪ What are the results?
▪ How do the results relate to other results in the field?
▪ What are the implications for research and society?
• Example journal clubs: https://www.jneurosci.org/content/by/section/Journal+Club
• More information about requirements and format:
https://www.jneurosci.org/content/jneurosci-journal-club
Learning outcomes
• Describe the different forms of memory and compare and contrast their function and
neural substrates.
• Explain the function of different spatial cell types in the hippocampal formation.
• Describe the phenomenon of hippocampal replay and explain its hypothetical function in
memory retrieval and maintenance processes.
• Describe the principal milestones of memory development and explain how studying
memory may give insight into the operations of the memory system in adulthood.
• List key molecular/genetic candidates implicated in memory function and describe
dominant theories about the molecular mechanisms supporting memory formation.
• Describe evidence showing how stress affects memory and explain influential theories of
anxiety disorders (such as post-traumatic stress disorder, PTSD).
,• Critically evaluate research articles in the field of (animal) memory research and give a clear
and coherent presentation of it to peers.
• Constructively participate in discussions about the methods and findings of a research
article (e.g. by asking relevant questions at appropriate times, engaging in discussions with
others about the article, etc.)
• Write a short (~1500 words) review article based on recently published findings.
Neural basis of cognition: overview
Neural systems of memory
• Two broad memory categories: implicit
(nondeclarative) and explicit (declarative) memory
• Two memory ‘systems’ subserved by distinct brain
regions
• Simply, implicit memory relates to knowledge we
acquire un-sub-consciously while explicit memory
relates to knowledge we acquire consciously
o Remember how to ride your bike is an example of
implicit memory whereas knowing what you had
for breakfast this morning is a type of explicit
memory
o Implicit memory is memorizing skills, habits,
conditioning and reflexes, while explicit memory
is episodic and semantic
o Episodic memory involves the ability to learn, store, and retrieve information about
unique personal experiences that occur in daily life. It is hard to know to be sure you are
studying episodic memory in non-verbal animals. We much often study spatial memory.
o Sematic memory involves memory of facts. You can’t recall the event, but you just
know, so impossible to study in animals
Neural systems of memory: Implicit memory
• Patients suffering from hippocampal amnesia can recall recently
learned words if they are primed with the first 3 letters of the word,
otherwise not
o This type of memory doesn’t rely on hippocampus but on cortex
• Hippocampal patients can also acquire a new skill – learning to
trace a star while viewing hand through mirror
o Skill motor learning not dependent on the hippocampus, but on
for example basal ganglia and cerebellum
-> The hippocampus is essential for explicit/declarative memory (such as conscious recall), but
not for implicit forms of memory such as priming and procedural learning.
Neural systems of memory: Explicit memory
• Explicit memory involves four operations:
o Encoding (memory formation)
o Consolidation (strengthening of a new memory)
o Storage
o Retrieval
• Explicit memory involves an interaction between the hippocampus and cortical regions
• Episodic (memory of events) and semantic (knowledge of facts) memories are two types
explicit memory
,• While implicit learning takes time (but then you know it without thinking), explicit learning is
quite fast, but always requires conscious
Neural systems of memory: Explicit memory – Patient H.M.
• Patient H.M suffered severe temporal lobe epilepsy
• His hippocampi were bilaterally removed to try to alleviate his epileptic systems
• Following his surgery H.M suffered anterograde amnesia (could not form new memories)
and temporally graded retrograde amnesia (could not recall his recent past)
• But he could still remember old memories!
-> Hippocampus plays a role in consolidation of memories but not in storage or retrieval ->
Memory is stored somewhere else, probably the cortex
Neural systems of memory: explicit memory – Evidence in rodents
• Rats were trained on a contextual fear-conditioning paradigm – they
received a foot shock in a particular environment
• The hippocampus was lesioned at varying intervals following training
• Animals who’s hippocampus was earlier lesioned after training
showed less freezing (so accurate recall) then animals where the
hippocampus was later lesioned
• The hippocampus is required for memory encoding and
consolidation, but not for storage
Neural systems of memory: explicit memory – Semantic memories
• Semantic memory, on the other hand, is thought to rely on cortical circuits.
• However, semantic memory formation is thought to require the
hippocampus – patient H.M. could not acquire new knowledge (semantic
explicit memory).
• Once semantic memories are ‘made’ they can be recalled without the
involvement of the hippocampus.
Semantic memories to semantic categories
• Semantic memories are structured into semantic categories, which are context-
dependent and flexible -> Boundaries are not fixed
• For example, a cat belongs to the category "cat," but categories can have different
dimensions such as size. A cat may be considered big compared to a smaller cat
but small compared to a lion. This shows how categorization depends on context.
• Semantic categories are flexible and can change as we learn new information. When
encountering a new animal, we might adjust our existing categories or create a new one
-> This demonstrates that category boundaries shift dynamically based on experience and
learning.
Semantic categories: face or vase?
• The ventral visual pathway or ventral stream
(visual cortex through temporal lobe) is
involved in visual object categorization in
humans and monkeys -> ‘What’ pathway
o Increased connectivity of ventral stream
• Increased connectivity of FFA when people saw face
instead of
vase
, Neural-circuit and molecular mechanisms of memory
• At the circuit level memory is thought to be underpinned by
changes in synaptic connectivity - long-term potentiation
(LTP)
• If pre-synaptic cell fires reliably before post-synaptic cell, and
it does so at a high enough rate than the synapse will undergo
strengthening such that a future action potential from the pre-
synaptic cell is more likely to evoke a response in the post-
synaptic cell than before LTP induction
• LTP has been investigated most extensively at hippocampal
synapses (Schaffer collaterals).
Spike-timing-dependent-plasticity (STDP)
• Synaptic plasticity may be mediated by precise spike-time
synchronization of pre- and post-synaptic cells
• If pre-synaptic cell fires just (<20ms) before post-synaptic cell, long-
term potentiation (LTP) occurs
• If post-synaptic cell fires just before pre-synaptic cell, long-term
depression (LTD) occurs
• If more than 100ms separate activity from two cells, no plasticity
occurs
Animal models in cognitive neuroscience
Animal models: rodents
• Rodents are used in behavioral tests because they have well-
characterized neural circuits, share cognitive and genetic
similarities with humans, and allow controlled, reproducible
experiments on learning and memory.
• Radial Arm Maze: A behavioral task in which rodents
navigate a maze with multiple arms to find food rewards,
testing spatial memory and hippocampal function.
• Morris Water Maze: A spatial learning task where rodents must locate a hidden platform in
a water-filled pool using distal environmental cues, relying on hippocampal-dependent
navigation.
• Contextual Fear Conditioning: A learning paradigm where rodents associate a specific
environment with an aversive stimulus (e.g., a foot shock), assessing hippocampus-
dependent memory formation.
Use rodents to study place and grid cells
• Place cells: type of neuron in the hippocampus that
fires when an animal is in a specific location within its
environment, effectively forming a spatial map in the
brain. These cells play a crucial role in spatial
navigation and memory formation.
• Grid cells: found in the entorhinal cortex. Grid cells
fire in a hexagonal pattern as the animal moves, providing a coordinate system that helps
with spatial navigation and path integration
• Together, place cells and grid cells form the foundation of the brain’s internal GPS system.
