1. Learning & Memory in the Head Direction Cell Circuit Jeffrey Taube Psychological & Brain Sciences Dartmouth College Hanover, NH

2. Circuitry issues – How the Head Direction signal is generated? Involvement of vestibular & motor cues How visual landmark information is processed How HD signals guide behavior How head direction cells respond in 3-D, as well as under micro-gravity conditions? What our Lab studies:

3. Circuitry issues – How the HD signal is generated? Involvement of vestibular & motor cues How visual landmark information is processed How HD signals guide behavior How head direction cells respond in 3-D, as well as under micro-gravity conditions? Grid cell generation Review a number of HD cell studies that we have conducted that involve learning and memory and inform us about some of the underlying neural processes involved in navigation. What our Lab studies:

4. Contributors Stephane Valerio Brett Gibson Ed GolobJeremy Goodridge Gary MuirJeffrey Calton Ben Clark Others: Josh Bassett Joel Brown Paul Dudchenko Russ Frohardt Jennifer Rilling Mike Shinder Bob Stackman Sarah Wang Shawn Winter Ryan Yoder

5. Two Components of Spatial Orientation Location - Place cells - 1971 - John O’Keefe Directional heading But place cells do not provide information about directional heading. A second category of spatial cells encodes for directional heading : Head Direction cells - Postsubiculum (dorsal presubiculum) - found in many limbic system structures 1984 - James Ranck

6. Head Direction Cell Video

7. Head Direction Cell Properties Direction of head, not body position. Head direction in the horizontal plane. Fires whether animal is moving or still. Firing is independent of location and behavior. Each cell exhibits one preferred firing direction. Preferred firing directions distributed equally around 360º. 0° 90° 180° 270° Peak firing rate Preferred firing direction Background firing rate Directional firing range Head Direction (°) Firing Rate (spikes/s)

8. Where is the Postsubiculum? M Witter (1989) In Hippocampus: New Vistas Postsubiculum - Deep layers Dorsal portion of Presubiculum = Postsubiculum Subicular Complex Subiculum (S) Presubiculum (PRE) Parasubiculum (PAR)

9. 3 Typical HD cells from different brain areas Taube, Muller, Ranck (1990) J Neurosci; Taube (1995) J Neurosci; Stackman & Taube (1998) J Neurosci Head Direction (°)

10. Figure 2 # of Samples: 1267 Mean ISI: 12.14 Std. Dev.: 5.07  : 0.418 Info. Content: 2.021 Vector Length: 0.913 ATI: 23.7 Gamma function r: 0.977 Firing Rate (spikes/s) Head Direction (°) Time (msec) Numb er 0 50 100 150 0-500-10005001000 C Interspike Interval (msec) 0102030405060 Frequency (%) 8 6 4 2 0 10 12 Firing Rate (spikes/s) # of Samples: 815 Mean ISI: 14.57 Std. Dev.: 10.08  : 0.692 Info. Content: 1.853 Vector Length: 0.838 ATI: 39.8 Gamma function r: 0.933 Numb er 0-500-10005001000 0 25 50 75 8 6 4 2 0 0 10 20304050 60 70 Frequency (%) B # of Samples: 635 Mean ISI: 25.01 Std. Dev.: 20.67  : 0.826 Info. Content: 1.481 Vector Length: 0.872 ATI: 75.4 Gamma function r: 0.898 Firing Rate (spikes/s) Numb er 0-500-10005001000 0 10 20 30 5 4 3 2 1 0 Frequency (%) 0120204060100 80 A No evidence for theta-modulation

11. Inhibitory Excitatory Place Cells Angular Head Velocity Cells Grid Cells HD Cells Head Direction Cell Circuitry Interpeduncular Nucleus ? Prepositus Medial Vestibular Nucleus Supragenual Nucleus Retrosplenial Cortex Hippocampus Postrhinal Cortex Parietal Cortex Entorhinal Cortex Anterior Dorsal Thalamic Nuc. Lateral Mammillary Nucleus Dorsal Tegmental Nucleus Postsubiculum Taube (2007) Ann Rev Neurosci

12. White cue card acts as the sole intentional orienting cue.

13. Taube et al. (1990) J Neurosci 180° Cue Card Rotation The cue card exerts stimulus control over head-direction cell firing

14. What brain areas are important for visual landmark control of Head Direction & Place Cell activity? Place cell Place cell place fields also shift following rotation of the salient visual cue

15. What brain areas are important for visual landmark control of Head Direction & Place Cell activity? General view for processing visual information: Dorsal stream important for processing spatial information - Parietal cortex

16. What brain areas are important for visual landmark control of Head Direction & Place Cell activity? General view for processing visual information: Dorsal stream important for processing spatial information - Parietal cortex Ventral stream important for processing object recognition - Inferior temporal cortex

17. What brain areas are important for visual landmark control of Head Direction & Place Cell activity? General view for processing visual information: Dorsal stream important for processing spatial information – Parietal Cortex Ventral stream important for processing object recognition – Inferior Temporal Cortex Visual Tectal Pathway - Attention To test this, we conducted 90° landmark rotation experiments on HD cells in animals with lesions of various brain areas.

18. Head Direction cell responses to 90° cue card rotations Amount of Shift Frequency Distribution for Shift Amounts Control 90 270 0 180 Arrow represents the mean vector

19. Generative Circuit PoS Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas: Dorsal Tegmental Nuc. & Supragenual Nuc. Head Direction Signal Generative Circuit PoS: Postsubiculum ADN: Anterodorsal Thalamus LMN: Lateral Mammillary Nuc.

20. PoS: Postsubiculum ADN: Anterodorsal Thalamus LMN: Lateral Mammillary Nuc. Generative Circuit PoS Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Head Direction Signal Generative Circuit

21. Control Hippocampus lesion Limbic Pathway None

22. Visual Cortex Parietal Dorsal Stream Retspl PoS Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Dorsal Stream

23. Visual Cortex Parietal Dorsal Stream Retspl PoS Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Dorsal Stream ADN

24. 90 270 0 180 Parietal Cortex lesion Dorsal Stream Pathway Retrosplenial Cortex lesion 90 270 0 180 Control Hippocampus lesion Limbic Pathway Mild- Moderate None

25. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Ventral Stream

26. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Ventral Stream ADN

27. Entorhinal Cortex lesion 90 270 0 180 Parietal Cortex lesion Dorsal Stream PathwayVentral Stream Pathway Retrosplenial Cortex lesion 90 270 0 180 Control Hippocampus lesion Limbic Pathway None

28. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream PoS LDN Tectal Stream Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Tectal Stream via LDN: Lateral Dorsal Thalamus Superior Colliculus Pulvinar Superior Colliculus

29. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream PoS LDN Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Tectal Stream via LDN: Lateral Dorsal Thalamus Superior Colliculus Pulvinar Tectal Stream Superior Colliculus

30. Entorhinal Cortex lesion 90 270 0 180 Parietal Cortex lesion Lateral Dorsal Thalamus lesion Dorsal Stream PathwayVentral Stream Pathway Tectal Pathway Retrosplenial Cortex lesion 90 270 0 180 Control Hippocampus lesion Limbic Pathway None

31. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream PoS LDN Tectal Stream Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Direct Projection: Visual Cortex  PoS Postsubiculum

32. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream PoS LDN Tectal Stream Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: ADN LMN Direct Projection: Visual Cortex  PoS Postsubiculum Place cells HD cells

33. Entorhinal Cortex lesion 90 270 0 180 Parietal Cortex lesion LMN Recording 90 270 0 180 Dorsal Stream PathwayVentral Stream Pathway Retrosplenial Cortex lesion 90 270 0 180 Control Hippocampus lesion Limbic Pathway Lateral Dorsal Thalamus lesion Tectal Pathway ADN Recording Postsubiculum Lesions Hippocampal Place Cell Recording Place field absent Severe

34. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream PoS LDN Tectal Stream Entorhinal Cortex Hippocampus Visual Streams for Processing Landmark Information: Direct Projection: Visual Cortex  PoS Postsubiculum ADN LMN Place cells

35. Entorhinal Cortex lesion 90 270 0 180 Parietal Cortex lesion Hippocampal Place Cell Recording LMN Recording 90 270 0 180 Place field absent Dorsal Stream PathwayVentral Stream Pathway Retrosplenial Cortex lesion 90 270 0 180 Anterior Dorsal Thalamus lesion Place cell recording ADN Recording Postsubiculum Lesions Control Hippocampus lesion Limbic Pathway Lateral Dorsal Thalamus lesion Tectal Pathway None

36. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS LDN Tectal Stream Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Generative Circuit So, what can we conclude ? Superior Colliculus

37. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS LDN Tectal Stream Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Generative Circuit So, what can we conclude ? Superior Colliculus

38. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS LDN Tectal Stream Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Generative Circuit Some Role So, what can we conclude ? Superior Colliculus

39. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS LDN Tectal Stream Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Generative Circuit Some Role So, what can we conclude ? Superior Colliculus

40. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS LDN Tectal Stream Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Generative Circuit Some Role So, what can we conclude ? Superior Colliculus

41. Visual Cortex Inferior Temporal Parietal Ventral Stream Dorsal Stream Retspl PoS LDN Tectal Stream Entorhinal Cortex Hippocampus ADN LMN Subcortical Areas Generative Circuit Landmark control in ADN and LMN occurs because of the feedback loop from PoS  LMN and ADN. Some Role Conclusion: For processing visual landmark information: the direct pathway from Visual Areas 17, 18 --> PoS is critical. Superior Colliculus Major Role

42. How fast can Head Direction cells learn about the visual landmarks ?

43. Rats can learn landmark information very fast Here they learned about the visual cue card in a matter of minutes. 8 min Exposure 1 min Exposure 8 min Exposure 1 min Exposure 5 out of 8 rotated well Goodridge et al. (1998) Beh Neurosci

44. Is the hippocampus important for HD cells to learn about novel visual landmarks? Hippocampal lesion We can take advantage of the fact that HD cells have different preferred directions in geometrically different environments. Thus, a change in the shape of the environment will usually lead to a shift in the cell’s preferred firing direction Cylinder vs. Rectangle & Square Cylinder 1 Rectangle Cylinder 2 Square Cylinder 3

45. Suggests that learning the spatial information about landmarks is more like perceptual learning, where visual information can drive the system directly – it is not like episodic learning, which involves the hippocampus. HD Cell preferred directions remain stable in a novel environment across days, despite the absence of hippocampus Cylinder – Familiar Novel Enclosures Triangle Pentagon Golob & Taube (1997) PNAS Novel Enclosures across days

46. What is the evidence that HD cells can guide behavior ? Linkage between HD cell firing and behavior What you would like to see is that when a cell’s preferred firing direction shifts a certain amount, that the animal’s spatial behavior (choice) also shifts the same amount. Review a few studies with HD cells where we looked for this linkage. What happens with HD cells following a behavioral error? Does the HD also show a shift in its PFD?

47. Training Trials Test Trial Example 1: HD Cell information is not always used for solving Spatial Tasks : Tolman Sunburst Maze Muir & Taube (2004) Beh Brain Res

48. HD Cell Plots on Error Trials for 2 Different Cells Training TrialsTest Trials in which rat made an error ……. thus, directional heading information was present, but the animal did not use it to guide behavior. This could explain why they had poor performance – no learning took place.

49. StandardCue RotationNovel Environment Example 2: Animal solves a spatial task, but is not using HD cell information to guide its behavior Water Reward Rat trained in square to go to a corner with water reward relative to landmark. Receives 40-60 trials in standard session and performing ~ 77% correct. Rotation of landmark leads to an equal shift in the animal’s behavior and the HD cell’s preferred firing direction. Rat generalizes well in the rectangle – and goes to the correct corner – 78% correct. But HD cells shifted their preferred directions > 72° in 12 / 13 sessions (but their behavior did not shift the same amount)  little evidence that HD cell firing was guiding the animal’s behavior.  Behavior was not in register with the shift in the cell’s preferred direction. Landmark Cue

50. Square Session Rectangle Session Square Session Rectangle Session HD cell preferred direction remains the same HD cell preferred direction shifts Golob et al (2001) Beh Neurosci Recordings from same cell on two consecutive trials in the rectangle. In both cases, rat generalized well from training in the square and selected the correct corner in the rectangle. Cell’s preferred direction was different on both trials – but behavior was similar. Suggests that this cell’s firing was not strongly linked to the animal’s behavior.