The type of inhibition provided by thalamic interneurons alters the input selectivity of thalamocortical neurons.

A fundamental problem in neuroscience is how neurons select for their many inputs. A common assumption is that a neuron's selectivity is largely explained by differences in excitatory synaptic input weightings. Here we describe another solution to this important problem. We show that within the first order visual thalamus, the type of inhibition provided by thalamic interneurons has the potential to alter the input selectivity of thalamocortical neurons. To do this, we developed conductance injection protocols to compare how different types of synchronous and asynchronous GABA release influence thalamocortical excitability in response to realistic patterns of retinal ganglion cell input. We show that the asynchronous GABA release associated with tonic inhibition is particularly efficient at maintaining information content, ensuring that thalamocortical neurons can distinguish between their inputs. We propose a model where alterations in GABA release properties results in rapid changes in input selectivity without requiring structural changes in the network.

A Role for Thalamic Projection GABAergic Neurons in Circadian Responses to Light.

The thalamus is an important hub for sensory information and participates in sensory perception, regulation of attention, arousal and sleep. These functions are executed primarily by glutamatergic thalamocortical neurons that extend axons to the cortex and initiate cortico-thalamocortical connectional loops. However, the thalamus also contains projection GABAergic neurons that do not extend axons toward the cortex. Here, we have harnessed recent insight into the development of the intergeniculate leaflet (IGL) and the ventral lateral geniculate nucleus (LGv) to specifically target and manipulate thalamic projection GABAergic neurons in female and male mice. Our results show that thalamic GABAergic neurons of the IGL and LGv receive retinal input from diverse classes of retinal ganglion cells (RGCs) but not from the M1 intrinsically photosensitive retinal ganglion cell (ipRGC) type. We describe the synergistic role of the photoreceptor melanopsin and the thalamic neurons of the IGL/LGv in circadian entrainment to dim light. We identify a requirement for the thalamic IGL/LGv neurons in the rapid changes in vigilance states associated with circadian light transitions.SIGNIFICANCE STATEMENT The intergeniculate leaflet (IGL) and ventral lateral geniculate nucleus (LGv) are part of the extended circadian system and mediate some nonimage-forming visual functions. Here, we show that each of these structures has a thalamic (dorsal) as well as prethalamic (ventral) developmental origin. We map the retinal input to thalamus-derived cells in the IGL/LGv complex and discover that while RGC input is dominant, this is not likely to originate from M1ipRGCs. We implicate thalamic cells in the IGL/LGv in vigilance state transitions at circadian light changes and in overt behavioral entrainment to dim light, the latter exacerbated by concomitant loss of melanopsin expression.

A King's College London Global Health Society Event discussing Global Mental Health to increase interest in Psychiatry as a Career: A Pilot Study.

INTRODUCTION: Despite the launching of multiple initiatives to increase recruitment into psychiatry, the profession continues to remain undersubscribed. Studies have shown that teaching on global mental health can improve attitudes toward psychiatry in medical students. To the best of our knowledge, no studies have been published hitherto that evaluate if a brief teaching session (i.e. 60 minutes in duration) on global mental health improves perceptions of psychiatry and increases interest in this specialty as a career. SUBJECTS AND METHODS: We conducted a single-arm, pre- post- comparison study on participants who attended a King's College London Global Health Society event on Global Mental Health. Participants completed a survey before and after exposure to the event. Our aims were to detect and measure if there were any changes in perceptions of psychiatry and if a brief teaching session on global mental health would increase interest in pursuing psychiatry as a career. RESULTS: 71 out of 90 participants responded (77.8% response rate). Following exposure to the event, there were statistically significant improvements in the scores for, "Psychiatry is interesting" (pre-event score 4.41, post-event score 4.66 p value <0.001), "I would talk positively about psychiatry to other people" (pre-event score 4.02, post-event score 4.48 p value <0.00001), and, "I would consider psychiatry as a career" (pre-event score 3.24, post-event score 3.72 p value <0.001). CONCLUSION: The results of our pilot study suggest that a brief lecture on global mental health may improve perceptions of psychiatry and increase interest in this specialty as a career. We recommend that global mental health be introduced into the medical school curriculum since this may help to increase recruitment into psychiatry.